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[00:00:00] Michael Hawk: Okay. Get this. Imagine a creature that’s born already pregnant. Not only that, it’s pregnant with its own grandchildren. No mating, no waiting. Just a continuous telescopic unfolding of life. It sounds like something out of a sci-fi novel, but it’s likely happening on the underside of a leaf in your own backyard.

[00:00:20] Today we’re looking past the pest label to discover the mind bending biology of the aphid. Our guest today is a aphidologist, Natalie Hernandez. If you’re on iNaturalist, you might recognize her as one of the most prolific identifiers of aphids. With Natalie’s help today, we learn about these incredible insects, including why ants tend to them like livestock, how telescopic reproduction works, and we investigate why aphids are incredibly important to ecosystems.

[00:00:47] While a few aphid species can be pests to agriculture, most are critical parts of the food web. I’ve grown to love finding new aphid species when I’m out exploring, and I hope today’s episode will inspire you to look under a few more leaves. Maybe look on some flower buds and find a few of these incredible insects this spring and summer.

[00:01:06] So without further delay, Natalie Hernandez, I.

[00:01:09] Natalie, thank you so much for joining me today.

[00:01:11] Natalie Hernandez: Thank you for having me.

[00:01:13] Michael Hawk: You know, I don’t know if this will resonate with people or not, but when I started this podcast like five years ago now, aphids were actually one of the topics that were on my shortlist I wanted to cover, and for some reason it’s taken me this long to actually get to it.

[00:01:27] I feel like I’m finally ticking that box on my initial list and getting aphids the limelight that they deserve.

[00:01:33] Natalie Hernandez: It’s not a super well-known group. They’re so difficult to Id, so very few people wanna work with them.

[00:01:40] Michael Hawk: You say that they’re not super easy to work with. So I kind of wanna figure out how you got into aphids and maybe we can go back a couple of steps. Were you always interested in insects or maybe more generally nature?

[00:01:53] Natalie Hernandez: Yes, I have been very into animals in general since I was a little kid, so my cousins all called me Dr. Doolittle, and we all thought I was gonna be a veterinarian. But then when I started college and I majored in animal sciences, I just wasn’t really enjoying the classes. You had to have a lot of chemistry and genetics and things, and that’s not my bag.

[00:02:14] So I decided to take an entomology class because you had to have a collection and it fulfilled, an elective requirement for my degree. So I was like, that sounds fun, I’ll do that. And then I was getting 100% on all the exams. I did really well on the collection. And I said to the professor, I was like, I think I should probably be an entomologist.

[00:02:36] And he was like, yes, yes, you should. So we sat down and had a conversation about how it would work, and I changed my major my fourth year in college. Luckily the animal science major was also in the College of Agriculture at the University of Wisconsin where I went. So it wasn’t too difficult to switch over, but took that class and immediate was like this is what I wanna do.

[00:02:56] Michael Hawk: What was it about the insects that really drew you in?

[00:03:00] Natalie Hernandez: Obviously insects are so diverse, there’s a million of them and there’s so much to learn and you could spend the rest of your life studying insects and never learn everything. You just barely touch the surface. So I really liked that idea. Even if you become an expert in a certain field in entomology, there’s still so much for you to study and it’s not really something you can get bored of.

[00:03:22] And then also, I have a

[00:03:23] photographic memory. So I can see illustrations on pages in a book, and people show me a larva and I’m like, oh, that’s an immature insect volume one. I know I saw it. Let’s go flip through the book, and then I can get an idea of where it was in the book and I can find that picture again.

[00:03:40] I’m like, yep. See that’s what it is. That’s what you have. And I think that just made it easy for me to recognize insects and be able to sight ID them. As soon as I see an insect, it’s just like, oh, I know I’ve seen that before, or I know I’ve never seen it before. And so because of that, I think that was really helpful for me to be able to get into identification because that’s not a thing in general that a lot of entomologists can do.

[00:04:05] Michael Hawk: That says a lot about, where we’re gonna go in the conversation because I first, discovered you and your work through iNaturalist because you were helping to identify aphids I would log into iNaturalist and the 10 observations I made in May of 2020 suddenly you had, identified all 10 of them one day. So it seems like, you have found lots of productive ways to put the skill to use.

[00:04:27] Natalie Hernandez: Yeah, and it was fun finding iNaturalist ’cause there’s tons of aphids on the website and unfortunately they’re very difficult to identify with pictures, so I can only do so much. But someone told me, Hey, there’s this new website, you should go check it out. And it was during the pandemic that I first started looking at it when I was working from home.

[00:04:47] And there was not enough work for me to do for a 40 hour work week, but I still had to be logged on. So I would spend some time going through iNaturalist like, oh, I can just get these aphids done and at least it’s helping me keep my identification skills.

[00:05:00] But then there’s just so many aphids on iNaturalist. I wish I could help people identify more of them, but then I was like, I’m gonna go through all the aphids. It’s only gonna take me 10 years.

[00:05:13] Michael Hawk: Well, as, the uptake of iNaturalist increases, you’re constantly having to catch up.

[00:05:17] Natalie Hernandez: The winter is a little easier, especially, ’cause I usually go through the North American aphids first. So now that it’s wintertime here there’s not just people constantly posting ’em. I feel like the end of the summer is the worst, especially with Oleander aphid on milkweed, there are just millions of pictures of Oleander Aphid on milkweed, and I some days I’ll just go through and check them all as reviewed, especially if they’ve already been identified by multiple people.

[00:05:42] And I can just go through dozens of pages like mark all is reviewed, mark all is reviewed, ’cause they’re all aphids.

[00:05:48] Michael Hawk: Yeah. And that’s one of the more showy ones, so it makes sense that would,

[00:05:52] notice

[00:05:52] Natalie Hernandez: It is easier to id and, yes, it’s bright yellow and a lot of people are trying to grow milkweed for monarchs, so then they’re like, what’s all over my milkweed? I want this for monarchs. And it’s like, well, now you’re gonna get Oleander aphids too.

[00:06:05] Michael Hawk: I know I’m jumping like several steps ahead, but since we’re talking Oleander aphids. Maybe I could ask a question or two about them since they are one of the better known aphids. So, milkweed is known for having this sort of like toxic latex.

[00:06:18] That’s one of the reasons why monarchs are successful with that plant, because they get this sort of natural intake of the toxin that make them repulsive to predators. I’m wondering, does the same hold true for aphids? Are they protected by the milkweed?

[00:06:35] Natalie Hernandez: So that’s part of the reason why aphids nerii is bright yellow, so that’s called aposematic coloration, and it’s basically warning colors, and that’s why monarchs are also colored the way they are. When you see insects that are brightly colored, reds, yellows, stripy with black and white, like wasps and hornets and things, that’s pretty much saying, stay away from me.

[00:06:55] Either I’m venomous or I’m poisonous. And you don’t wanna mess with me. And of course a lot of predators have adapted also. A lot of ladybugs will still eat oleander aphids despite the fact that they might not taste all that great. But I’m sure there’s varying levels of toxicity too, and especially with some of the milkweeds are not quite as toxic as the others . So they can vary a lot in color. I’ve seen some that are very pale and then I’ve seen some that are almost orange or red, not quite red. And then most of ’em are just that bright yellow that you see. And they also do colonize a lot of the oleanders, which are also very toxic plants.

[00:07:36] Michael Hawk: So I guess my takeaway here is like everything in biology, there’s no 100% always true. It sounds like it’s good protection, but not perfect a hundred percent immunity to predation.

[00:07:48] Natalie Hernandez: My professor that I learned from, he’d be like, there’s an exception to everything with insects. Like nothing is absolute.

[00:07:55] Michael Hawk: Yeah. And I wanted to go back to the iNaturalist thing too because, I discovered iNaturalist during the same period of time during COVID, and it’s just such an amazing platform. The idea of spending some devoted time identifying things, I found that it tickles my brain in many ways because I’m learning in the process, I’m contributing to community science, and it’s kind of meditative in a way. It’s like you get into a zone when you’re doing that, and, it just is so much fun. I urge people, if anyone out there is interested in aphids or otherwise, start looking at iNaturalist.

[00:08:27] Natalie Hernandez: Yeah, it’s very easy to just lose hours sitting at my laptop identifying aphids. Especially, I mean, there’s obviously millions of observations on iNaturalist, and sometimes I get off on tangents too, where I start identifying things other than aphids. Like I went through all of the fire colored beetles one day, ’cause I realized someone was misidentifying a lot of them as Cucujoidea versus Pyrochroidae and vice versa. So I’m like, now I’m gonna go through. All the Cucujoids and all the Pyrochroids and make sure these larvae are correct.

[00:08:59] Michael Hawk: And then you’re helping their algorithim too, ultimately, in the future, if there’s enough successfully verified identifications, then the machine learning algorithm can hopefully learn from that and help you.

[00:09:10] Natalie Hernandez: It’s funny when it’s, not just aphids, but there’s so many other insects where it’s like, these things look very similar. So if you, aren’t like a lot of people, I always try to include an explanation with my IDs and say, this is this species because if you look at this character, this character this character versus the species, you originally had it identified as where you would see this character, this character. So check out those and see if you can see that difference. I get a little annoyed when I’m looking at other people’s comments and stuff, and they’re just like, no, that’s not what it is. And I’m like, okay, I don’t know if that’s the best way to approach it with a lot of people, I feel like if you just give at least a little explanation they’re more likely to change their ID and understand where you’re coming from. I try not to sound super arrogant, but I’m like, no, aphids are my thing. I’m an aphid expert.

[00:09:56] Michael Hawk: I think there’s so much to learn, so much that we don’t know. I don’t have an entomology background. I’m more of a generalist naturalist I’ve taken a few classes here and there and spent a lot of time in nature. So I’m not an expert, but you get a false sense of, accuracy sometimes from the machine learning recommendations, and I know early on I misidentified a lot, a lot of, not just aphids, but other things because they do look so similar and it is challenging. So thank you for the approach that you take. It’s definitely helpful in my opinion.

[00:10:26] One of the reasons I wanted to talk to you is aphids, I sometimes call them and I later found that Doug Tallamy uses a similar analogy. I used to think I came up with it myself, but I probably heard it from him that aphids are kind of like the plankton of land, because they fulfill an important role of converting plant energy into energy that other animals can use in the food web. And I think we’ll get into that here if we talk about the life history. Just tell me like at the highest level, what is an aphid?

[00:10:54] Natalie Hernandez: So the aphids they’re also called plant lice because they have sucking piercing mouth parts. They’re gonna insert those sucking, piercing mouth parts. They actually have a little straw inside that they can weave between plant cells. If you ever see their whole stylet when it’s extended out, it’s really interesting. It’s just a little clear, very long tube that they will weave into the phloem of the plant. And so they are phloem feeders. There’s also a lot of related Hemipterans that are xylem feeders. But because they’re phloem feeders, they’ve developed this specific filtering chamber in their digestive system that allows them to soak up the phloem, which is the plants, pretty much like the plant’s blood, but it’s very sugar heavy.

[00:11:37] So what they’re after is nitrogen. And so they suck up all of this phloem and then they’re filtering out all those sugars in all the water, mostly trying to get nitrogen and then other minerals and chemicals that are in the phloem that’s gonna help them grow. So then they excrete pretty much sugar water as poop, and that’s what they’re doing sitting on these plants.

[00:11:57] They’re just soaking up all of the sugary substance, excreting sugar water poop, which is called honeydew. Someone decided to try and give it a cuter name, and then that’s why you see a lot of other insects that come and interact with them like ants. A lot of people are really interested in the ant aphid relationship. A lot of people are very surprised by it when they see pictures and they’re like, what are these ants doing? Are they eating the aphids? And then I explained to them, no, they actually tend aphids for that honeydew. And so there’s not a whole lot of insects that produce honeydew the way they do, since a lot of other insects are xylem feeders, which is more water heavy, not quite as much sugar, so it’s not as sweet.

[00:12:36] But ants will attend related insects too, in the same way just trying to get some of that sugar water. And so they’re kind of their own distinct group because they’re the only insects with cornicles or siphunculi the two little tailpipes on the back end. And not all aphids have Cornicles or Siphunculi, I call them Siphunculi. A lot of other people call them Cornicles, and if you see Cornicles or Siphunculi, it’s definitely an aphid, but not all aphids have them.

[00:13:05] Michael Hawk: What function do those parts serve? Is that where the honeydew is excreted?

[00:13:09] Natalie Hernandez: Nope. The honeydew is actually from between the tailpipes, the siphunculi. The Siphunculi excrete alarm pheromones and wax. So When you see a colony sitting on a plant, if they’re disturbed by a predator, the Cornicles are kinda like smoke stacks. So they release these alarm pheromones, alerting the rest of the colony that there’s a predator nearby.

[00:13:30] And then you might see little globules coming out of the tips of the Siphunculi, which is wax. So if a predator comes up and bites them, it’s gonna gum up their mouth parts and make it more difficult for them to eat the aphid.

[00:13:41] Michael Hawk: Wow. I’ve seen those little droplets before and I had no idea. I just assumed that was the honeydew, but so interesting.

[00:13:48] Natalie Hernandez: And then they have that little tail in between the  Siphunculi, it’s called the cauda, and that’s for flicking the honeydew away from their bodies. Some of them have very long caudas because they’ll be. Sitting on a plate where they need to flick away a lot of the honeydew. But then there’s others that have shorter caudas and they don’t flick away the honeydew quite as much.

[00:14:06] Michael Hawk: Interesting. I know I’ve had the experience of parking my car under a tree and coming back and finding lots of little droplets of, I just always called it sap, but one day I was looking at the tree and saw, I think it was a cottonwood and there were lots and lots of aphids on that cottonwood. So I jumped to the conclusion that maybe that was actually honeydew that was being excreted.

[00:14:26] Natalie Hernandez: Yeah, lots of people tell me that. They’re like, my car is covered in honeydew. And then they find out that’s actually aphid poop, and they’re like, oh, gross.

[00:14:36] Michael Hawk: And they’re super diverse, right? Can you paint a picture of the diversity?

[00:14:41] Natalie Hernandez: So there’s about 4,500 described species worldwide, and I’m sure there’s more that we haven’t even realized, especially as we’re getting into more molecular analysis with insects in general, we’re finding a lot of different relationships that we didn’t really understand before. So I’m sure there’s a lot more that we just either don’t realize they’re their own species, two things that might look very similar, or that we just haven’t seen because of their life habits. There’s a lot of aphids that feed on roots and so I don’t think those have been well studied. There’s about two dozen subfamilies now, I think. And identifying them to subfamily can be difficult even with just pictures because some of them are kind of similar, but some of them are very different.

[00:15:26] And the biggest one is going to be Aphididae aphis is the main genus of aphids and there’s over 600 species and that genus alone. I feel like just looking at the different ones that I’ve seen all over the globe on a iNaturalist is so interesting.

[00:15:42] They don’t follow the typical insect rule where they’re more diverse in the tropics and then less diverse further north or further south. They’re the opposite. So they’re more diverse in temperate climates and less diverse the closer you get to the equator. And they’re actually not very common in the southern hemisphere either.

[00:16:01] Most of their diversity is gonna be North America and Europe. And in Asia, there are some funky ones that people tag me in pictures of Asian aphids. I’m like, I have no idea what that is. So I think there’s a lot more diversity than we realize in Asia too.

[00:16:16] I think they just haven’t been studied as much, especially not in more northern climates where it’s more temperate and not tropical.

[00:16:23] Michael Hawk: Are there any hypotheses as to why there’s that sort of inversion in diversity in the tropics?

[00:16:29] Natalie Hernandez: I’m sure I’ve read stuff talking about it, but I can’t recall what the reasoning is. Doing all my research, my graduate research in Wisconsin, it was just amazing how diverse they were just in Wisconsin ’cause Wisconsin has so many different biomes throughout the state, and so many people were just like, oh, well there can’t be that many aphids in Wisconsin can there?

[00:16:49] And I’m like, well, just looking in potato fields for my grad research, I found over 200 species. I don’t think people really realize how diverse they are and especially in those less tropical areas. And I wonder, if it might be because of their size, since a lot of those tropical insects tend to be huge, but all aphids are just tiny. I don’t if that might have something to do with it. Like their ability to use resources and grow faster and more tropical climates might be less ’cause they just don’t get that big to begin with. Like the giant aphids at max are six millimeters.

[00:17:22] Michael Hawk: Are there more generalists in the tropics?

[00:17:24] Natalie Hernandez: Yeah, I wonder if that might be doing it too. Like aphids, since they’re host specific and some of them only feed on one species of plant that might be affecting their ability to colonize in the tropics too. And I don’t think they like warm weather in general. Lab studies have been done with pest species and they found that they like 65 to 75 degrees, and when you start getting much warmer than that, they don’t reproduce as well. So that might be another reason too, since the tropics are generally

[00:17:52] Michael Hawk: Yeah. Interesting. One of the things I think that people recognize, especially gardeners, and we’ll get into the whole, like which aphids are considered pests and why, and all of that later, but they’re known to reproduce very quickly. Like they have a very high reproductive potential. So can you tell me a little bit about their reproductive process?

[00:18:11] Natalie Hernandez: So since their parthenogenetic, they reproduce mostly via parthenogenesis, which is females give live birth to females which give live birth to females. And so it’s all females just reproducing asexually for most of the growing season. The only time we really see sexual reproduction is gonna be in the fall when they try to lay eggs on host plants to over winter, to survive a colder winter.

[00:18:36] So we rarely see males, I can’t identify males. Most of the time they look very different. They’re funky looking compared to the females. And so, their whole life cycle is just very complicated for insects, for animals in general because they can reproduce asexually and then they can switch into sexual reproduction.

[00:18:54] And a lot of the time that’s associated with host plants because some aphids host plant alternate, so they’ll have their non-sexual reproduction on a certain host plant. And then at the end of the growing season, they’ll move back to a different host plant to do their sexual reproduction. And then they over winter there, and then in the spring they move back to their other host plant.

[00:19:15] Michael Hawk: That’s crazy.

[00:19:16] Natalie Hernandez: It’s just amazing how quickly their colonies can build up because they have that type of reproduction and they’re actually born pregnant with the cells that will become their granddaughters. It’s called telescoping generations. And that fact just blew my mind when I learned it. I’m like, I can’t even imagine being born pregnant with your granddaughter.

[00:19:36] Michael Hawk: And that’s like a wonderful analogy too, telescoping, because you can kind of envision a telescope with multiple pieces that extend, or a telescoping antenna, the one piece is inside the next piece, which is inside the next piece.

[00:19:48] Natalie Hernandez: It’s really cool that they do that, and most of them are clones of each other, so most of their genetic makeup is just copying themselves over and over again. So those populations can build up super quickly, and especially when you get a species introduced into an area where it’s not native, it takes a while for the native predators to catch up to the fact that there’s something else for them to eat there. And so that’s when those populations can really go crazy.

[00:20:15] Michael Hawk: Now when we see aphids, a lot of times, you know, we will see how big the populations can actually get.

[00:20:20] Natalie Hernandez: I’ve seen thousands on one plant. Yeah.

[00:20:22] Michael Hawk: Are they just all sort of living independently or are there some social aphids that are, you know, fulfilling different roles or helping each other in some respect?

[00:20:33] Natalie Hernandez: So it’s mostly just aggregations. It’s safety in numbers, but when you get insects that start to aggregate, there’s always the potential for them to evolve into social casts. That’s what makes insects social versus solitary is if there’s overlapping generations and brood care. And then also caste differentiation.

[00:20:54] So when you think of social insects like bees, you have queens and workers and soldiers and things like that. And so the thing that makes them social is that the soldiers and the workers don’t reproduce. It’s just the queen that reproduces and those other females are all sterile. But then there is the potential for them to actually take care of the queen’s broods.

[00:21:17] And then they have different functions in the colony. So at this point aphids can all still reproduce and they don’t have caste differentiation. So they’re still considered solitary but then there are some that are starting mostly in South America or in Mexico I think.

[00:21:33] And in Asia there’s Pseudoregma is one genus I can think of that they actually have soldier aphids now. And so those are actually nymphs that do not ever mature to adults. And so they just protect the aphid colony. but at some point In the future I would not be surprised if they form true use social colonies.

[00:21:53] Michael Hawk: I found some tidbits when I was researching for this discussion mentioning soldier aphids, and that blew my mind ’cause I’d never heard of that before.

[00:22:00] Natalie Hernandez: I haven’t seen a ton of them but I’ve seen a lot of pictures on iNaturalist, but a lot of ’em are in Asia, the Subfamily where it’s most common is hormaphidinae. They’re a lot of gallformers and things like that, and we don’t have a ton of them here in North America, in the United States, so I haven’t seen any soldier aphids myself, like in person. But then looking on iNaturalist, I’ve seen lots of pictures of them and so they’re pretty common, especially in Asia. There’s some that feed on bamboo, so people post pictures of them on bamboo all the time, and those I can recognize pretty easily.

[00:22:37] Michael Hawk: So as we kind of meander through the metaphorical maze of, of aphids, you mentioned gallforming aphids, and I’ve seen a few gallforming aphids here in California. How common is that among aphids?

[00:22:51] Natalie Hernandez: Very common. I’m terrible with the galls themselves. That’s a whole other area of expertise. I get tagged in a lot of gall pictures and I’m like, I’m sorry, i’m terrible at identifying galls. But there’s a bunch of people on iNaturalist that are really great with gall identification, so I’ll tag them a lot. I can only remember their iNaturalist tags Adam Krantz.

[00:23:11] Michael Hawk: He’s a past podcast guest actually.

[00:23:13] Natalie Hernandez: He’s great. I tag him in so many gall pictures and I’m always like, let me know if you get sick of me tagging you. And Charlie Eisman is another person that also is on bug guide. So I’ve interacted with him on bug guide a lot with IDs of Aphid galls and things like that.

[00:23:29] Michael Hawk: And just to amplify the shout out to Charlie Eisman as well, he’s also a leaf mining insect expert. One of the reasons why I mentioned this is you mentioned there’s 6,000 plus species, so I don’t expect you to necessarily know this, but there’s a few different gallforming aphids that we get on Manzanitas out here, and what I was wondering about is I went down a rabbit hole trying to figure out the lifecycle of these, because it seems like for people that plant native Manzanitas in their yards, that maybe already have these aphids a lot of people have noticed among my bio blitzing friends that are into native plants. So it’s, it’s a pretty, selective sample, but it’s hard to maintain the aphid populations in yards.

[00:24:14] And it got me wondering if, like you mentioned that during the fall they may switch host plants for the sexual reproduction phase. I’m wondering if there’s a missing host plant that we need to help those aphids persist?

[00:24:27] Natalie Hernandez: Nope, they’re mono holic, so that means they complete their entire lifecycle on Manzanita. So they don’t host alternate. I’m sure there’s all kinds of chemical signals and things that alert them to healthy plants and versus unhealthy plants. And I, I studied potato virus y in grad school and we made like little pan traps in potato fields to see where aphids were landing in potato fields. And we found that they like to land at the field edge where there is a differentiation in color. Like you can see the difference between two different kinds of plants. So we had pan tramps, like right on the edge of the field, and then we’d go 10 feet in and then 25 feet in and then 50 feet in. And then we would go to have a trap, right in the center of the potato field. And we used yellow tiles because previous research has shown that aphids tend to be attracted to the color yellow.

[00:25:23] And they think it’s because viruses cause chlorosis in plants, which is the yellowing of leaves. So they think that attracts aphids, like the virus is attracting the aphid to the plant with that color differentiation, and that makes them transmit the virus more. So we used yellow tiles to see where they were landing in the potato fields. And so I I think there’s a lot of signals that aphids use to decide if they want to infect a plant. I imagine it’s easier for them to colonize a plant that’s already sick too, because the immune system of the plant is gonna be lowered and less likely to be trying to attack them as they’re feeding. Plants can even exude chemical signals to parasitoid wasps. So when aphids start feeding or anything starts feeding the plant is like, oh no, this insect is feeding on me. I’m gonna release these chemical signals that will attract parasitoids and other predators and come kill whatever’s feeding on me.

[00:26:21] And so I feel like it’s just so complicated to try and figure out why aphids might choose one plant. Like I’ve seen aphids choose one plant and they’re all over it, and then the plant next to them same plant is totally fine, they’re not on that plant. So, I think there’s just a lot that goes into their decision to colonize a plant and I’m highly anthropomorphizing here, obviously. They’re just like, “this plant has all these things that we need to be able to colonize it, but we’re gonna stay away from that one over

[00:26:49] Michael Hawk: so many insects seem to do that as well. The galls are another great example where you can have two identical plants next to each other and one’s covered and one is clean.

[00:26:58] One thing I was wanting to ask you too is about the size of aphids. You mentioned at the start that they’re pretty small and that’s partly why they’re overlooked. But I think even within the realm or definition of small there’s a bit of a variance there as well. Those manzanita aphids are tiny, almost microscopic.

[00:27:17] Natalie Hernandez: I believe the smallest record it was aphis gossypii. So they have a dwarf morph, dwarf morph, and they can get below a millimeter. And I think usually around one millimeter is the estimate. But I’ve definitely seen some that measured probably like 0.9 millimeters. And we generally measure their size based on the top of their head down to the base of the cota, so just the tip of their abdomen. When we talk about body length, that’s what we’re referring to is just that dorsal line that goes from the head to the end. And so I know  aphis gossypii can be less than a millimeter, but then you get some of the giant aphids in the Lachninae which the biggest ones can generally, I think the biggest I’ve heard of is about six millimeters.

[00:28:01] And so especially the giant bark aphid is a super common aphid I see all the time. And that one can get up to six millimeters. So a lot of the time people are like, oh, that’s an aphid? It’s huge. And it makes me laugh ’cause I’m like, six millimeters is not huge, but yes, for an aphid.

[00:28:15] Michael Hawk: Yeah, six times bigger. If I, if I saw a human that was six times bigger than me, I would be a little frightened.

[00:28:21] Natalie Hernandez: I don’t see things eating the giant bark aphids very often and they’re often some of those giant aphids are also ant attended, so I think that helps keep them safe too, is like not only are they huge and gonna be tougher for ladybugs to eat, but then they also have ants protecting

[00:28:36] Michael Hawk: So, yeah, the ant interaction that you mentioned earlier is one of the things I think a lot of people discover about aphids. They see this behavior and you just, alluded to the fact that the ants will actually protect the aphids. They aren’t just there to eat the honeydew, but I think it goes beyond that.

[00:28:51] Can you tell me a little bit more about the relationships that develop with ants?

[00:28:56] Natalie Hernandez: Yeah, so it’s not something I’ve studied extensively, but in my understanding they actually tend aphids. So they take care of them because they are a food source and it’s only certain kinds of ants. Ants tend to prefer different foods as well. So some of them prefer very sugary foods, some of them prefer more fatty foods, and some of them switch at different times of year.

[00:29:17] So at some part of the year, they’re like, “we’re gonna go for high sugar stuff right now.” And then later in the year they switch to fattier foods to help them over winter and things like that. But they will actually take care of aphids. They protect them from competitors. They actually milk them, so they’ll rub their antennae down them to be like, “release some honey dew.”

[00:29:35] And then the aphids will release the honey dew and they take it and they’ll actually move aphids around. So when it’s certain times of the season, it starts getting cold, they will take aphids down to the roots. So sometimes you can dig up a plant and you’ll see aphids in the roots with ants still taking care of them.

[00:29:53] So they’re often called ant cows because that’s another one of their common names. Since the ants will actually herd them and tend to them and take care of them. And I know there’s some that have specific relationships where they’re only attended by certain ants. There’s some that are attended by a few different species or genera of ants and things like that too. And then there’s some that aren’t ant attended at all. They’ve never been observed with

[00:30:17] Michael Hawk: hmm.

[00:30:17] Natalie Hernandez: taking care of them.

[00:30:18] Michael Hawk: Those oleander aphids that we find on milkweed. Do you ever see ants tending to them?

[00:30:24] Natalie Hernandez: I believe they can be, but it’s not as common. And I wonder again, because of the toxic plant that they’re eating…

[00:30:29] Michael Hawk: not a preferred source.

[00:30:30] Natalie Hernandez: Definitely. If you’re looking for sugar water, it’s probably not the best to come from Oleander aphids.

[00:30:36] Michael Hawk: So this whole ant interaction, it’s always amazing to witness and see and it makes me wonder like what sorts of surprising discoveries have you personally witnessed?

[00:30:48] Natalie Hernandez: It’s really interesting to see on iNaturalist, the aphids are not supposed to be here. A while ago I was contacted by someone from the California Department of Agriculture that was like, “Hey, people are seeing these aphids on liquid amber. And I thought they were the giant bark aphid I mentioned earlier is Longistigma caryae. And they’re like, I thought it was Longistigma caryae but I now I’m looking again. And I was like, no, pretty sure that’s, and I think I had identified some of them as Longistigma caryae and then we were talking about it. I’m like, I’m pretty sure those are Longistigma liquidambarus.

[00:31:22] They only colonized liquid amber and they’re supposed to be Asian. They weren’t supposed to be here in North America. But then this person sent me some links and they were like, I think that’s what this might be. And we realized that there’s quite a few observations. From California of the species on liquid amber and they’re not supposed to be there. So they were introduced at some point and they were trying to mitigate that, especially ’cause they had gotten some specimens sent to them from homeowners near where they worked in California and people were finding them on their trees. I think a lot of aphids do get introduced in nursery stock. People import trees and their eggs are very, very tiny and they hide their eggs in little nooks and crannies along the branches waiting for bud break in the spring. Japanese maples are a big import and I’ve been seeing pictures of a genus called Yamatocallis and they’re very common on maples in Asia again, but they’re not supposed to be here. And I’ve been seeing people posting a lot of observations in California again, where it’s definitely that genus. It’s a very distinct genus. They have kind of, they’re called smokey wing maple aphids cause they have just like a dark band along the wing that looks like smoke. And then there’s also other aphids that are really common on Maples, japan, a Siphon and Drepanaphis, they’re all in the same sub family as  Yamatocallis. So it’s not totally surprising to see them here in the United States.

[00:32:46] But at the same time, seeing those observations, I’m just like, oh, that’s new

[00:32:50] Michael Hawk: Yeah.

[00:32:51] Natalie Hernandez: the us.

[00:32:52] Michael Hawk: So you mentioned that, you know, they’re introduced and there’s some concern about them. Do you see many aphids transition from just introduced in sort of a novelty to maybe, having a more negative impact, like classified as an invasive species.

[00:33:08] Natalie Hernandez: Originally when Soybean Aphid was introduced, it caused a lot of problems. So Soybean Aphid was introduced in Wisconsin in 2001, and then we started seeing it spreading all over soybean aphids. I worked for the Wisconsin Department of Agriculture in the summer of 2007 as an intern, and we had to go around soybean fields in Wisconsin trying to scout for soybean aphid and see like how many plants were infested with them. And we had to like try to estimate numbers, which I would go through soybean fields and nearly all the plants within the first 10 feet of the field would just be covered in, I would estimate, tens of thousands of aphids on one soybean plant. And then you’d go to the next field and you wouldn’t see any.

[00:33:55] And then you’d go to the next field and it would just be tens of thousands of aphids all over every single soybean plant along the edge of the field. And that was causing a lot of issues, obviously, because it was reducing the yield of the plants. And it took a while for them to really get it under control. But then over time, we stopped seeing them. So it was like we were seeing tens of thousands and then in the years that followed we just weren’t really finding that many.

[00:34:21] And the professors I worked with at the University of Wisconsin would still be going out and scouting and trying to find soybean aphids, and they just weren’t at the level they were back in the early two thousands when they were first introduced. So they were classified as invasive at first because they had negative impacts.

[00:34:37] But then over time, I think that the parasitoids and things we do have here caught on that there was a new food source and ladybugs started eating them more. And of course we had the multicolored Asian lady beetle introduced to control aphids and now it’s everywhere. They’re not a pest like emerald ash borer, where emerald ash borer just went and killed all the ash trees like aphids even when they’re introduced and when they’re invasive, they just don’t cause that level of damage. And I can’t think of any aphids where they’ve totally decimated a certain type of plant in a non-native habitat.

[00:35:12] Michael Hawk: Interesting and it kind of gets into one of the topics I wanted to touch on and that’s how aphids a lot of times kind of have a bad rap, especially with gardeners.

[00:35:20] I, I know lots of gardeners, if they see an aphid, their first instinct is we gotta get rid of these things. So maybe could you talk a little bit about that? In your backyard garden is that a fair characterization?

[00:35:31] Natalie Hernandez: I feel like if you see a colony getting out of control on like vegetable gardens, they can cause problems with your vegetable plant being able to produce as much. But even in the end, your vegetable plant is still gonna produce probably more fruit than you really know what to do with.

[00:35:47] Our tomato plants always just still produce tons of tomatoes, even if we see aphids on them. I think a lot of people worry that they’re going to cause problems, but they’re really just a natural part of the ecosystem. They’ve always been here. They’re native to here. Most species are native to north America. obviously We have a lot of introduced and established species like the Oleander aphid. We think it’s native to the Mediterranean region, but even though it’s all over milkweed, it doesn’t really prevent milkweed from reproducing and it hasn’t caused a population loss in milkweed. So I think a lot of people obviously think invasive or think introduced. And think of other pests that are going to completely destroy certain plants. But that’s just not something that aphids have historically done. But, I really don’t think aphids are as big of a problem as a lot of people think they are, and so I feel bad when people are like, what should I do to control the aphids? And I’m like, nothing, just leave ’em alone. It’ll be fine. a lot of them are gonna move plants at certain times of the year.

[00:36:48] So one day you might look at your plant and it’s absolutely covered in aphids. And then the next day they’re gone because they’re starting to move host plants and a lot of the time, parasitoids and ladybugs will come in and lace wings will come in and start taking care of the population for you. So, you don’t really need to do anything.

[00:37:06] And a lot of the time, aphids will attract predators for more serious pests too ’cause they’re an easy food source. There’s so many of them on one plant. A lot of positive predatory bugs are gonna come in and start eating them, and then that’s gonna track them to your garden and it’s gonna help them eat other things in your garden.

[00:37:24] So I generally tell people to just leave aphids alone. If they’re really decimating a plant, if you have a plant that’s just absolutely covered in them, a good strong spray of water will knock a lot of them off the plant. And you can manually squish them and remove them from your plants. But most of the time I think they’re just unsightly and people don’t like the idea of having insects on their plants.

[00:37:49] Michael Hawk: Yeah. There’s this expectation of pristine leaves with no leaf holes or, you know, anything like that on, them.

[00:37:57] Natalie Hernandez: Which aphids get blamed for leaf holes A lot. I often explain to people, I’m like, aphids can’t cause holes in the plant. They don’t have chewing mouth parts. They have sucking, piercing mouth parts. So if you see something that’s chewing holes in a plant. It’s not the aphids that are on your plant, something else is coming to do that.

[00:38:15] Michael Hawk: Yeah. I like to tell people if they find aphids to check on them periodically because something interesting is probably going to happen. Like you mentioned, maybe some ants will come and start tending to them, or you’ll see a mass of lace wing eggs, which are these beautiful little bright green eggs on a little stalk and it’s so fun to see that or maybe lady beetles, you know, all that.

[00:38:36] Natalie Hernandez: The lace wings actually do that, so the larvae won’t eat each other as they’re hatching. Yeah. Since they’re predatory and they’re generalists soft-bodied insects are their preferred prey. But I guess sometimes they’ll just eat each other if they can get to each other. So that’s why they think that evolved, that little silk stock that the eggs are on.

[00:38:53] Michael Hawk: Wow. Yeah. I had not heard that. I had heard that it’s like a protective mechanism for predators that, you know,

[00:38:59] Natalie Hernandez: Mm.

[00:39:00] Michael Hawk: the little stalk might break.

[00:39:01] Natalie Hernandez: There’s probably multiple reasons why it evolved over time, but that’s what I was taught in my entomology classes.

[00:39:07] Michael Hawk: And You mentioned how like one day they may just all be gone and, and I suppose sometimes it’s a mystery as to where they went, but how do they disperse?

[00:39:15] Natalie Hernandez: So mostly it’s through the winged morphs. So aphids can be winged or wingless. Um, the wingless ones are the ones that most people see because that’s what colonizes a plant, that’s what’s all over the plant. And then those are the ones that are gonna fly to the new host plant. And then a lot of the aphids that were on the original host plant are gonna die off, and it’s just the end of their life cycle.

[00:39:36] And it’s really interesting seeing those different morphs. And then at the end of the season there’s egg laying morphs and then the males come out. And so those look very different than the morphs you see during the summertime. So it’s just, uh, just they’re very complicated life cycle of moving around from one plant to the other and doing sexual versus asexual reproduction.

[00:39:55] Michael Hawk: So as I said at the beginning I’ve became aware of your work through the identification that you do on iNaturalist, and I’ve learned a lot from you in particular that there are a lot of aphids that you just can’t identify from photos. So tell me a little bit about how you approach identification by photos?

[00:40:15] Natalie Hernandez: So with a lot of the publications that we use for identification use dichotomous keys. And so, you know, does it have this character or this character, And you pick one and you move on in the key. And a lot of those are based on slide mounted specimens.

[00:40:30] So those are aphids that have been collected and then they’ve been chemically cleared. We actually use a very caustic chemical, potassium hydroxide, and it pretty much clears out all the internal organs, everything inside the aphid and just leaves the exoskeleton. And then you take the exoskeleton and you put it through alcohol to just dehydrate it. And then you put it in some cold oil and then you put it a little drop of Canada basal. Thinned with citrus oil and then you put the aphid in that little droplet of resin from a tree pretty much and put a slide cover on top of it. That’s how I was trained to identify aphids.

[00:41:06] I really wish we could get like a global project going where people photographed aphids like they do on iNaturalist and then collected them and then we could confirm IDs with slide mounts. Because I feel like a lot of aphids could be identifiable, more identifiable, with pictures.

[00:41:24] But because most of our knowledge and how do ID aphids is based on slide mounted specimens, it’s difficult to translate that into pictures, a lot of the time. There’s just certain characters I can’t see in pictures. For example, one really common aphid is Aphis spiraecola, which is the spirae aphid. And it’s a polyphagous aphid, so it feeds on a number of unrelated plants.

[00:41:48] But then there’s also Aphis pomi, which mostly feeds on apples and related plants, and it looks a lot like Aphis spiraecola. But in order to differentiate the two, you have to look for what are called tubercles, which are this tiny little bumps along the side of the abdomen. And it’s like the presence or absence of tubercle can differentiate those two species. Otherwise they look pretty much the same. And so I’m just like, how am I supposed to see that in pictures on a insect that’s two millimeters?

[00:42:20] And so I’m like, sorry, it could be one of these two species. They’re very similar. This is how I would tell them apart. And obviously you probably can’t see that in most pictures. And so a lot of people are very understanding about that. Some people, I don’t know if they don’t believe me or if they’re just like, no, I wanna idea it as a species. So sometimes a little tough explaining some of those things to people because they just can’t really see what I’m talking about.

[00:42:42] And certain aphids are gonna be very distinct. Like long Sigma carry, the giant bark aphid, I feel is super easy to Id ’cause they’re so big and they have a very distinct pattern. And especially the winged morphs have very distinct wing venation. I can ID those from pictures pretty easily, even if it’s not that great of a picture. But then something like a bunch of the Aphis can be super similar. And so it’s really hard to identify those. And then of course, host plant association is often important.

[00:43:12] So all these keys that we use to identify aphids are based on host plant. So it goes by host plant genus. And then it’s like on this genus of host plants look at these characters to differentiate these species. So if you don’t know what their host plant is, especially in the wing morphs it can be very difficult to tell them apart. And there’s a lot, of Macrosiphini, they have very long cornicles or siphunculi. They’ve got long legs and they’ve got big, long bodies. And they all, like all the winged morphs, just look very similar a lot of the time. So, just certain characters are obviously gonna be really difficult to see in pictures. I think if we could get more pictures associated with slide mounted specimens, we would see that they do look different. I think there’s definitely certain ones where I’m like, I’m pretty sure that’s this species, but I can’t see if it has this character, this character.

[00:44:04] But from what I have identified myself and what I’ve, I’ve seen live on plants, like I think it’s this, but I’m not a hundred percent So a lot of the time, if I’m pretty sure I’ll still Id it as that species, but if I’m, if I can’t for sure say like, I don’t think there’s any other species that looks like this.

[00:44:22] I’m just like, well, it could be this, but I’m not positive.

[00:44:26] Michael Hawk: I think I have a lot of aphids on the iNaturalist that are, only genus or maybe family level at times. That happens and you touched on something, I think that’s, really important. You mentioned that the host plant association is super important, and then we’ve mentioned a few different species that have either the Latin name or the common name references, a potential host like Oleander Aphid or Rose Aphid or Potato A, like these different things.

[00:44:55] And, just because it’s in the name doesn’t mean that’s what you’re gonna find on that plant.

[00:45:00] Natalie Hernandez: Yeah, that’s usually the first main host. It’s found on, like Rose Aphid is very host specific and it’s a pretty distinct aphid. They have long black siphunculi and they’re on roses. They will also colonize Valerian, I think it is. And there’s another genus too that they’ll colonize. And I’m blanking on it right now, but I think they only occur on three genera and Rose is their preferred primary host.

[00:45:25] But then you get potato aphid, which is in the same genus. So rose aphid is Macrosiphum rosae, potato aphid is Macrosiphum euphorbiae, and it’s a polyphagus species. It’s one of the most polyphagus species of aphid, so it can be found on hundreds of unrelated plants. So even if you know host plant, sometimes it might not be helpful with those species. And so sometimes I have to say that too. Where I’m like, oh, I’m pretty sure this is potato aphid, and it’s known to that plant, but I’m, I’m not positive if anything similar looking can also be found on that plant. If there’s any other Macrosiphum that colonize it. But with Rose Aphid, usually I see that on a plant, and even if the pictures aren’t great, I’m like, yep, that’s Rose Aphid.

[00:46:06] It’s on a rose. It’s got those long black siphunculi, there’s nothing else it could be.

[00:46:10] Michael Hawk: And what resources would you recommend people look into to learn more about either aphids in general or more specifically identifying aphids, like are some of these dichotomous keys available online?

[00:46:21] Natalie Hernandez: Yep. the biggest one is going to be aphids on the world’s plants. It’s a website and it’s just all these dichotomous keys are arranged by plant genus, and that’s gonna be the best resource for anyone who really wants to get into aphid identification. And that’s made by two European entomologists. unfortunately, I think there are a lot of host plant interactions missing, especially from North America. Like I definitely see pictures where. It’s like, oh, this was on this plant, and then I go check that database and there’s only one species recorded on that plant, but it’s definitely not that species.

[00:46:56] So that does still happen. But that is a really great resource for just at least trying to get an idea of what you might be seeing on a certain plant. But if you don’t know the genus of plant, it could be difficult to figure out what the possibilities are. Like sometimes we can go by family. But that’s a little bit more difficult. And they’re all for the wingless morphs. So these are all wingless colonies that were associated with that host plant. So if you have a winged morph, winged morphs will actually sometimes probe non hosts plants. So I’ve seen winged morphs on some of the maple feeding ones I was mentioning, like Drepanaphis and Drepanosiphum.

[00:47:31] They’re very distinct aphids. So they’re very, like even the winged morphs are pretty easy to id. But then I’ve definitely seen them on things other than maples, other than the genus acer. And then I have to explain to people like, these colonized acer, but you’re seeing this on this plant and so it’s probably just probing, looking for a new host plant and it’s not actually gonna use this plant

[00:47:52] Michael Hawk: Interesting. So it’s like taking a taste and like, eh, I don’t like this one so much.

[00:47:56] Natalie Hernandez: yep. Yeah. They will actually insert their mouth parts and it can take, it can take a while for them to probe the plant, but they’ll insert their mouth parts, get into the phloem, tap into it and be like, Nope, no, this isn’t the plant I want.

[00:48:07] Michael Hawk: So interesting. I mean, that makes sense. I guess they have to have some variability in that way in order to evolve over geologic or ecological time. You know, as, as things change, they, they need to have that little randomization, I suppose.

[00:48:24] Natalie Hernandez: So a lot of the wing wharfs, we kind of associate with the wingless ones and say, oh yeah, that must be this species as well ’cause it’s with this colony. But if you just see one single one on a random plant, it’s like, it could be this, but I don’t know if it’s actually colonizing that plant or just stopping by to get a taste.

[00:48:41] Michael Hawk: yeah. yeah. You can’t draw a conclusion in that case. I’ve seen you mentioned parasitoid wasps. Sometimes when I’m looking at an aphid colony, I’ll see all sorts of interesting things.

[00:48:51] There’ll be the adult aphids. Sometimes maybe you’ll even see a live birth happening or something crazy like that. But then there are often lots of exoskeletons as they’ve gone through their different in stars. But occasionally there’ll be a big, kind, light tan, bloated looking aphid sometimes with a little hatch.

[00:49:12] Natalie Hernandez: Yeah.

[00:49:13] Michael Hawk: Tell me what’s going

[00:49:14] Natalie Hernandez: Yep. Those are parasitized. So those are called mummies. When we see an aphid that’s brown and bloated, and it’s kind of like that tan and the exoskeleton also looks a little bit more papery I don’t have a better word to describe that, but it kind of reminds me of like parchment paper.

[00:49:29] And so it’s like that is the parasitoid developing inside the aphid. So the parasitoid wasps comes and lays an egg in the aphid, and then the larvae is developing inside of it. So as it develops more and more, and the aphid gets more into its full size. The larvae eventually kills it, they always kill the aphid.

[00:49:49] And so you get that big brown bloated aphid when the parasitoid larvae pupate inside the aphid. And a lot of the time you can tell that their mummies, because the legs actually aren’t touching the plants anymore. The parasitoid pupa will actually make silk along the ventral side of the aphid along the sternum or along the stomach. And so it’ll actually attach itself to the plant with its own silk, and it’s just encased in the dead aphid, which is pretty much just an exoskeleton at that point. The aphids aphid is no more, and then the little, they’ll have a little hole in the back when emerges from the pupa and the adult wasp exits the aphid.

[00:50:28] So when you see those little brown casings with just a little hole, that means that the wasp has completed its lifecycle

[00:50:35] Michael Hawk: and there’s usually one one wasp inside an aphid?

[00:50:38] Natalie Hernandez: When you get to things like caterpillars, especially big caterpillars, you can have parasitoids that will lay one egg that multiplies into hundreds of larvae through parthenogenesis, and then it’ll, so you’ll just have one good example are the tomato hornworms.

[00:50:53] If you see ’em with little white things all over ’em, a lot of people think those are eggs. Those are actually parasitoid wasps pupae, and so they had all developed inside that tomato horn worm, and then they emerge and spin cocoons on the caterpillar. So parasitoid wasps are fascinating as well. I haven’t, researched them much, but I know a lot of people really researched that interaction between aphids and the different parasitoids and how we can use them to control aphid populations.

[00:51:19] Michael Hawk: I almost feel like I have to repeat it because I just always assumed that it was, lots of eggs got inserted into that tomato horn worm, but okay.

[00:51:26] Natalie Hernandez: Yeah. I don’t know if that particular species does it, but there are some that will lay multiple eggs. And there’s some that’ll just ’cause the idea of stinging the same caterpillar multiple times I imagine would be difficult ’cause those tomato hormones will thrash and just move around trying to get the parasitoid off.

[00:51:44] I’ve seen videos where they just completely knock parasitoid wasps over with their front end. So over time, parasitoids evolve to just lay one egg that

[00:51:53] Michael Hawk: Wow.

[00:51:54] Natalie Hernandez: multiple times because at least they only have to sting

[00:51:57] the caterpillar once.

[00:51:59] Michael Hawk: of energy.

[00:52:00] Natalie Hernandez: Mm-hmm. Yeah. Yeah. So it’s it’s insane

[00:52:02] Michael Hawk: Yeah. That’s, that’s just so amazing. I love this conversation. This has been so much fun. Before we wrap up, is there anything else, anything else in the world of aphids that you would want to talk about?

[00:52:14] Natalie Hernandez: I think we covered a lot of it. Obviously I can talk forever about aphids. We could have like a six hour podcast and I’d probably still be talking. They’re just, they’re such amazing creatures I feel like they do get overlooked and a lot of people don’t realize how complicated their life cycles are from the ones that will spend their whole life on one plant versus ones that live on one plant for a while, move to another.

[00:52:36] Their reproduction. Some of them we’ve never observed. A male in the wild. They are obligate parthenogenetic, just females, only females like the Oleander aphid, again, we’ve never observed a male except under specific lab conditions, I think. It’s just amazing to think how some of them evolve into these different roles where it’s like, Nope, we’re just going to totally do away with males, only reproduce with females giving live birth to females. And then the other ones that still utilize eggs to over winter in the much colder areas, like in Wisconsin where I studied aphids, we’d find eggs all over plants all the time. It’s just amazing that over time they evolve these different behaviors and now in the future, probably gonna have some species leaning more towards social casts and actually those colonies like cockroaches and termites and things like

[00:53:26] Michael Hawk: Yeah, let’s fast forward a couple million years and see what things look like then.

[00:53:30] So you mentioned that they’re so overlooked, so how can listeners help in that regard? Like I imagine posting pictures is helpful, having that amazing study that you said of comparing slide mounted aphids with the photos.

[00:53:43] Natalie Hernandez: Yeah, that would be great.

[00:53:44] Michael Hawk: How can people find aphids?

[00:53:46] Natalie Hernandez: You just look at any plant you see and there’s probably gonna be aphids on it at some point, so I’m just constantly checking plants as I’m walking around. It’s just keeping your eyes open and realizing that there can be these teeny tiny insects all over these plants, because I think a lot of people just aren’t

[00:54:01] Michael Hawk: Yeah, I mean at, at the risk of turning this into that six hour podcast, that you brought up another thing, some aphids are like fuzzy and woolly too. They aren’t always these smooth bodied.

[00:54:11] Natalie Hernandez: Wooly aphids

[00:54:12] Yeah, a lot of people think green, right? They think, oh, it’s a green aphid, but they can come in almost any color. The big red ones on Asteraceae are almost always Uroleucon. It’s, they’re called giant large daisy aphids or giant daisy aphids, ’cause they get to be like three or four millimeters.

[00:54:29] So if you see big red aphids on  Asteraceae , it’s probably Uroleucon. But it’s a very complicated genus. There’s a ton of species. And with molecular analysis, we realize we don’t know them as well as we thought we did. So I don’t identify those two species with pictures very often.

[00:54:46] And with molecular analysis, the, a methodologist who taught me how to ID aphids said that they analyzed some of them and some that they thought they, some looked very similar Morphologically, they did molecular analysis and they’re different species. And then there were others that were very different morphologically, they thought they were different species, so they did molecular analysis and turned out they were the same species. So he is like, I don’t, I, I gave up on  Uroleucon. I don’t ID them anymore. And I’m like, okay.

[00:55:13] Michael Hawk: So complicated and so many parallels too. I guess just, as we said, everything in biology, it seems like we run into these same dilemmas at times.

[00:55:22] Before we do wrap up, do you have any upcoming projects, publications, anything like that you would like to highlight for people?

[00:55:30] Natalie Hernandez: I am mostly just trying to work on Bug guide and iNaturalist. I went through, I think all the aphids on Bug guide up to a certain year, like I think it was back during the pandemic again, like 2020, 2022 in there. I’ve gone through most of the aphids on bug guide and done what I can, and I go back and check periodically and try to get those IDed for people.

[00:55:50] And then with iNaturalist, I’m just gonna continue chipping away at all the aphids on iNaturalist. And I’ve also been working on a set of diagnostic aids. I started them for my job when I was an identifier for the USDA.

[00:56:03] And so I just, I kept my focus on aphids ’cause I was like, I don’t wanna have to learn another difficult group. I’m good with this one. And started making these diagnostic aids where I actually describe all the characters that I’ve been talking about. And I just make pages for each species. And I started with the 25 most common ones we see, and then a bunch of people were like, you need to make more of these.

[00:56:22] These are great. So I’m just trying to chip away at those and I hope to get them online at some point. So that people that wanna identify aphids can have those as a tool.

[00:56:31] Michael Hawk: If you get those online or anything else, of interest, let me know because I’ll make sure to share it with listeners either through my newsletter or on the podcast or whatever. I would love to be able to share that. And if somebody is really stumped with an aphid on iNaturalist, can they tag you for help?

[00:56:47] Natalie Hernandez: Oh yeah. Anytime. Mm-hmm. Lots of people tag me in all of their aphid posts, such as n as in Natalie, M as in Marie, Hernandez, N M Hernandez. That’s my tag. And I’m, I’m happy to look at anything people tag me in and I know some people feel bad tagging me all the time and I’m like, Nope, I’ll look. I’ll take it.

[00:57:05] Michael Hawk: It’s a, a wonderful service, so thank you for that. And aside from your iNaturalist handle, is there anywhere else people could follow you if they’re interested in your work?

[00:57:16] Natalie Hernandez: the only other thing I have on Instagram, I have Nats crafts, G-N-A-T-S dot C-R-A-F-T-S. It’s my artwork, so I do entomology artwork and I have an Etsy shop where I paint and sell watercolor, paint, and paper samples. So if you like entomology art, I try to post my stuff on there.

[00:57:34] Michael Hawk: fun to take a look at.

[00:57:35] Natalie. As I said, this has been so much fun. It’s such an interesting space and overlooked like we talked about. So thank you so much for working this into your schedule and I, I hope you enjoyed it.

[00:57:47] Natalie Hernandez: Thank you so much for having me. Like I said, I can talk about aphids forever, so it’s always fun to try and get more knowledge out there and try to help people with aphid IDs.

[00:57:55] Michael Hawk: Wow. I hope you enjoyed that as much as I did. And before we go today, I just wanted to give a quick shout out to our volunteer Brooks Neely for his editing help in this episode I.