Butterflies, Moths, and...?

Fall semester starts Tuesday, and hawkwatch starts Saturday, so it's about time I put something up. Here's a little selection of moths from this month:

This is a Primrose Moth (Schinia florida):

This one's a Bleeding Flower Moth (Schinia sanguinea):

And this one's a Polymorphic Pondweed Moth (Parapoynx maculalis):

These guys might well make one ask "Why are these moths and not butterflies?" Which might well lead to the question "What IS a moth, anyways?" and "What is a butterfly?" The first version of the answer is, they're all insects in the order Lepidoptera. Wonder of wonders, they're also all of the Lepidoptera; everything in this order is called either a butterfly or a moth. (Well, sort of... more on that in a moment.)

One of the older butterfly guides had an intro where the author tried to answer the question "What is a butterfly?" by saying, roughly, that a butterfly was brightly colored and flew in the daytime. But of course, some things we call moths fit this very nicely. He then pointed out that he's seen crepuscular butterflies in the tropics, so it's not an easy question at all. And if we're using color as a criterion, then what do we make of this guy?


This is a Hackberry Emperor (Asterocampa celtis).

And this is a Common Checkered Skipper (Pyrgis communis):

This last one is the sort of... And that gets us into the heart of the issue. The skippers have been considered a separate suborder, and currently are listed as a superfamily within the Rhopalocera, along with the butterflies (also a superfamily). Most sources do call them butterflies, in any case. The Rhopalocera, though, is listed as one suborder within the Macrolepidoptera, which includes 4 other superfamilies. Although the Macroleps include 60% of the species in the Lepidoptera, they actually include a minority of the superfamilies (and families, not coincidentally). All of those other superfamilies are called moths!

So, what's a butterfly? It's something in the Rhopalocera, possibly excluding the skippers. What's a moth? Any lepidopteran that isn't a butterfly! (Or a skipper....)

Things were often much simpler before we started doing proper phylogenetic analyses, but I'd rather deal with the complications if it means a better understanding of where things came from.

Growing Pains

Mid-semester is always a busy time. The bugs don't care, though, so here's a nice find from last week:

Coral Hairstreak (Satyrium titus), Illinois Beach SP, Lake Co, IL 7/9/2014

This is a Coral Hairstreak, (Satyrium titus). They're quite common around here, and always a welcome sight in July.

Here's what one looked like last month:

Coral Hairstreak (Satyrium titus), Illinois Beach SP, Lake Co, IL 6/14/2014

Everyone knows that caterpillars turn into butterflies, right? (Well, most of them turn into moths, but that's a story for another day.) But what about other insects?

Dragonfly Nymph (order Odonata), College of Lake County, IL, 7/16/2012

Many groups undergo metamorphoses similar to butterflies. This frightening critter is a young dragonfly. (Dragonfly nymphs are very hard to ID to species, I'm afraid.)

Racket-tailed Emerald (Dorocordulia libera), Gander Mt. Forest Preserve,
Lake Co, IL 5/23/2012

And here's an adult, in this case a Racket-tailed Emerald (Dorocordulia libera).

Seaside Grasshopper (Trimerotropis maritima), Illinois Beach SP,
Lake Co, IL 7/21/2013

Here's a Seaside Grasshopper (Trimerotropis maritima). Despite the name, they're quite common in the old sand dunes at Illinois Beach State Park. And here's a young one:

Seaside Grasshopper (Trimerotropis maritima), Illinois Beach SP,
Lake Co, IL 6/12/2014

You can tell it's young by the short, stiff wing pads, compared to the long, mobile wings of the adult. Clearly, though, grasshoppers (like the rest of the order Orthoptera) don't undergo a full metamorphosis. Neither do the true bugs in the order Hemiptera.

So there is variation in metamorphosis in insects. (We don't see it at all in Arachnids - young spiders or scorpions look like tiny versions of their parents.) Any time we see variation across a group, it provides a possible test of evolutionary mechanisms. In this case, Kukalova-Peck discussed the fossil record of insects back in 1978, concluding that metamorphosis had evolved separately in several different lineages. (1) Thirty years later, Belles agreed, arguing that we can trace the more complete, holometabolan lineages through hemimetabolan fossil stages, (2) while still concluding that the story is murky at best.

In 2001, Yang used insect metamorphosis to test the hypothesis that organisms with modular developmental strategies (like metamorphic insects) should show more diversification over time. They found that, indeed, holometabolan lineages showed more diversification than ametabolan or hemimetabolan ones. (3)

(1) Kukalova‐Peck, J. (1978). Origin and evolution of insect wings and their relation to metamorphosis, as documented by the fossil record. Journal of Morphology, 156(1), 53-125.

(2) Belles, X. (2011). Origin and evolution of insect metamorphosis. eLS.

 

(3) Yang, A. S. (2001). Modularity, evolvability, and adaptive radiations: a comparison of the hemi‐and holometabolous insects. Evolution & development, 3(2), 59-72.

Beetles with a Checkered Past (and Future)

It's been a good summer so far for these beauties:

Trichodes nuttali, Illinois Beach SP, Lake Co, IL, 6/29/2014

Enoclerus analis, Lyons Woods FP, Lake Co, IL 7/30/2013

Thanasimus dubius, Lyons Woods FP, Lake Co, IL 6/2/2014

These are all Checkered Beetles, in the family Cleridae. The family is a small one, only 3600 species worldwide, with only 300 or so in North America. (That's about 1% of the 350,000 species of beetle worldwide*, and about 0.1% of the 25,000 beetles recorded from North America.)

They're predators, eating other insects. The larvae often feed on wood-boring larvae, including those of Pine Bark Beetles responsible for quite a few large-scale losses of trees in the western and south-eastern US. Which explains why this little tiny family still warrants over 5,000 citations on Google Scholar.

Interestingly, they use the sex pheromones of their prey to find them. The technical term for this is a kairomone, which is a chemical produced by one species that ends up benefiting another species. Herms, et al. looked at this in the predator-prey pair Ips pini (a bark beetle) and Thanasimus dubius (the last Clerid shown above). (1)  Billings & Cameron showed that different predatory beetles respond to different genera of pine bark beetles, an interesting bit of specialization. (2) (They also showed that pine sawyer beetles, Monochamus titillator, responded to one of the bark beetles. Given their habit of laying eggs in freshly dead pine trees, this makes sense. They only responded to one species of beetle, though, which leads me to wonder if that beetle is more lethal to the pines, or if both the bark beetle and the sawyer beetle show preferences for certain species of pine.)

Beetles can be surprisingly attractive little critters, but it shouldn't surprise me by now just how intriguing their lives can be.

*All of these figures from Bugguide.net.

(1) Herms, D. A., Haack, R. A., & Ayres, B. D. (1991). Variation in semiochemical-mediated prey-predator interaction: Ips pini (Scolytidae) andThanasimus dubius (Cleridae). Journal of chemical ecology, 17(8), 1705-1714.

 

(2) Billings, R. F., & Cameron, R.S. (1984). Kairomonal responses of Coleoptera, Monochamus titillator (Cerambycidae), Thanasimus dubius (Cleridae), and Temnochila virescens (Trogositidae), to behavioral chemicals of southern pine bark beetles (Coleoptera: Scolytidae). Environmental Entomology, 13(6), 1542-1548.

 

Return of the Prairie?

Here's a nice find from this morning, first located by a friend of mine:

Prairie Warbler (Setophaga discolor), Grant Woods FP, Lake Co, IL  6/27/2014

This is a male Prairie Warbler (Setophaga discolor), and he's only the third one I've ever run across in the county. The first one, in fact, I never did manage to see. Thankfully, they have a very distinctive voice -- a slightly buzzy, very musical series of notes running up the scale. Their song always reminds me of Arethra Franklin trying to sing a Northern Parula ditty.

They breed in early-successional shrublands, which are in rather short supply in this area these days. Back in the 70's, though, they bred in Illinois Beach State Park. That habitat hasn't changed much over the years, and I don't know why they disappeared.

I mentioned that this was the third one I've found here? The first two were last year in May. Given that this guy's been singing away for at least two weeks, and he was joined by a second male, I have to wonder if this is a signal of a range expansion back into the county. In the case of this particular male, it's likely to be an unsuccessful one, since he's still singing his heart out at the end of June. (Typically, a male that's found a mate will spend a lot less time singing by now, since there's no longer any need to attract a female.) But that's the way that ranges grow -- the first few birds into a new area will probably not succeed. Once a couple of birds have found mates, and we have a few nestlings who have grown up here, then the next birds to wander into the area will see a reason to stay, and we have a new expected species.

Evolution can be seen as an exploration of the incredibly large universe of possible genetic programs, set against a wildly varying environment of constraints. An occasional individual wanders into new territory, and if it's really lucky, an entire population will someday follow it. But that's an abstract way to view things. Genetic programs only evolve when they're in a body that can actually do things, and in this case, we're seeing the abstract concept of exploration playing out in very concrete, and very musical, little warblers.

Wolves and Bears, Oh My!

Rain threatened all morning, then class in the evening, so here's a couple of zoo shots:

Red Wolf (Canis rufus), Henry Doorley Zoo, Springfield, IL 5/21/2013

This is a Red Wolf (Canis rufus).

Mexican Gray Wolf (C. lupus baileyi), Cheyenne Mountain Zoo, Colorado Springs, CO 12/27/2013

This is a Mexican Gray Wolf (C. lupus baileyi).

At various times, the Red Wolf has been considered a subspecies of the Gray Wolf (thus C. lupus rufus) (1) and a hybrid of Coyotes (C. latrans) and Eastern Gray Wolves (C. lupus lycaon) (2, 3). (It's been argued that Eastern Gray Wolves aren't properly placed in C. lupus, (4) as well.) This is all a rather obscure academic dispute, I suppose. Even most people who care that there are wolves in the US don't know the ins and outs of their relationships. Except for one thing -- Red Wolves are a critically endangered species, with a re-introduced population living on Alligator River NWR in northeastern North Carolina. If they were indeed to be considered a subspecies of the Gray Wolf, the reintroduction program might itself be endangered. Trying to do science well is hard enough. Trying to do it well with this sort of controversy lurking behind every abstract must be a bit of a nightmare.

Here's another couple of critters with similar histories:

Alaskan Brown Bear (Ursus arctos alascensis), Alaska Zoo, Anchorage, AK 8/12/2012

Grizzly Bear (U. arctos horribilis), Cheyenne Mountain Zoo, 12/27/2013

These are both Brown Bears (Ursus arctos), although currently considered different subspecies. There have been quite a few different subspecies described, from as few as 5 to as many as 90! In the 1920's and 1930's, though, the Grizzly (Ursus horribilis) was still considered a separate species. (5) Again, since Grizzlies are listed as endangered, while Brown Bears as a whole aren't, these decisions actually matter. And here's an interesting question for the near future, along these lines:

Polar Bear (U. maritimus), Cincinnati Zoo, Cincinnati, OH 3/29/2012

This, of course, is a Polar Bear (Ursus maritimus). If you're into bears, you've probably heard of the Grolar Bears that have recently been shot in the Arctic reaches of North America. Those would be Ursus maritimus X arctos hybrids. Hybrids between species indicate that those species are closely related, and indeed research suggests divergence times as old as 5 million years (6) and as recent as
150,000 years. (7) While there is evidence from DNA of hybridization, and a couple of older specimens, recent discoveries of wild grolar bears has raised the specter of climate change pushing the two species into more contact, with grizzlies moving north as the climate warms and polar bears spending more time on land as the ice melts. If they are capable of hybridizing, and the hybrids are born into a changing world that favors a melding of the two species, could we see the recently evolved Polar Bear merging back into the Brown Bear they evolved from? And if so, what would we call the resulting population, and how would we deal with it in terms of conservation?

Science is all about trying to refine our view of the world. Often that requires a focus which nearly shuts out all but the little piece we're working on. But the rules our world plays by don't always allow the Ivory Tower approach -- the things we do really do make differences in the world around us.


(1) Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press.
  
(2) VonHolt, BM; et al (12 May 2011). "A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids". Genome Res 21 (8): 1294–305. 

(3) Wayne, R. and S.Jenks. 1991. Mitochondrial DNA analysis supports extensive hybridization of the endangered red wolf (Canis rufus)" Nature 351:565-68.
 
(4) Chambers SM, Fain SR, Fazio B, Amaral M (2012). "An account of the taxonomy of North American wolves from morphological and genetic analyses". North American Fauna 77: 1–67. 

(5) Baggley, G. F. (1936). Status and distribution of the grizzly bear (Ursus horribilis) in the United States. In Transactions of the North American Wildlife Conference (Vol. 1, pp. 646-652).

 

(6) Miller W, Schuster SC, Welch AJ, et al. (July 2012). "Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change". Proc Natl Acad Sci U S A 109 (36): E2382–90.

 

(7) Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay et al. (2010). "Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear". Proceedings of the National Academy of Sciences 107 (11): 5053–5057.

Seeing the World through Other Eyes

I came across this little beauty this afternoon at Van Patten Woods:

Rainbow Bluet (Enallagma antennatum), Van Patten Woods FP, Lake Co, IL 6/21/2014

This is a female Rainbow Bluet, one of our prettiest damselflies. One of the neat thing about damselflies (and dragonflies) is their ability to navigate by polarized light. (1) Since polarization varies across the sky depending upon the sun's position, this is a very useful trick. Water reflects light in a polarized fashion as well, which is probably useful for a dragonfly as well. Other insects can do this as well:

Bibio albipennis, Lyons Woods FP, Lake Co, IL 6/2/2014

Golden Northern Bumblebee (Bombus fervidus), Gander Mt. FP, Lake Co, IL 8/3/2013

Many of them can also see ultraviolet light, which bees use to locate the appropriate flowers and the nectar within those flowers. (2) These guys have evolved strategies to take advantage of this ability:

Six-spotted Orbweaver (Araniella displicata), Ryerson FP, Lake Co, IL 5/31/2014

Orbweaver spiders place UV-reflective decorations within their webs to actually attract prey -- bait, if you will. (3)

When you're wondering what your favorite pet thinks about the world, it's worth remembering that he or she almost certainly doesn't perceive the world the way you do. So much of ecology would be completely hidden without the tools we have, based on theory hashed out by generations of physicists, built by engineers for those biologists with the imagination to conceive of a world that looks completely different than the one we see.

(1) Meyer, E. P., & Labhart, T. (1993). Morphological specializations of dorsal rim ommatidia in the compound eye of dragonflies and damselfies (Odonata). Cell and tissue research, 272(1), 17-22.

 

(2) Guldberg, L. D., & Atsatt, P. R. (1975). Frequency of reflection and absorption of ultraviolet light in flowering plants. American Midland Naturalist, 35-43.

 

(3) Craig, C. L., & Bernard, G. D. (1990). Insect attraction to ultraviolet-reflecting spider webs and web decorations. Ecology, 616-623.

 

 

Family Trees Revisited

Here's an interesting trio:

Edith's Checkerspot (Euphydryas editha), Flaming Gorge NRA, Daggett Co, UT 5/27/13

Steel-blue Cricket Hunter, (Chlorion aerarium), Illinois Beach SP, Lake Co, IL 8/2/2013

Red-bellied Snake (Storeria occipitomaculata), Lyons Woods FP, Lake Co, IL 3/5/2012

What's the link here? These are all illustrations of a common pattern in evolution. Not so many years ago, butterfly guides talked about 3 suborders of Lepidoptera -- moths, butterflies, and skippers. Similarly, Hymenopterans were split into three groups -- parasitic wasps, stinging wasps and bees, and sawflies. The squamate reptiles consisted of two -- the snakes, and the lizards. In each case, the assumption was that these groups had split apart early, and then each had diversified on its own.

Here's a rough cladogram, to give an idea:

Cladistic analysis, these days greatly enhanced by DNA analysis, has shown that this pattern doesn't often hold. Instead, what we see is early splits leading to "basal" groups that don't diversify much, (like several of the sawfly families and some "primitive" moths), a succession of further splits that don't do much, then one or two groups that split and apparently cross some sort of adaptive threshold, followed by an impressive radiation. So we find that the sawflies, for example, are actually not a natural group at all -- they're just those hymenopterans that didn't become wasps. Here's a more recent conception:

We find the same with Lepidopterans -- butterflies make up part of one suborder, along with most of our moths. Even within that suborder, most of the groups are moths, as are a large majority of the species. The old breakdown of moth, butterfly, skipper isn't tenable.

Even the snakes, clearly a natural group themselves, turn out to be nested within one of several suborders of lizards, long thought to be a separate group.

(A quick note on the use of scare quotes above -- these are two terms I cordially detest when used this way. A primitive species is one that died out a long time ago -- modern species have all been evolving since that early ur-ancestor. And a basal group, if you examine any cladogram that purports to show "the basal" species, is whichever lineage that emerged from that first split either without diversifying much, without becoming "interesting", or that has since lost most of its earlier diversity.)