Tag Archives: arthropod

North America’s Big Five Centipedes

When Halloween comes around, snakes and spiders tend to steal the show. Yet centipedes, in my experience, tend to evoke even stronger reactions from people — I have met many entomologists who would happily handle a tarantula but recoil in horror when faced with a giant centipede.

In the United States there are five species of giant centipedes in the family Scolopendridae. Today, in the spirit of Halloween, I give you the Big Five: where they are found, what they do, and why I love them.

Blue Tree Centipede (Hemiscolopendra marginata)

The blue tree centipede. Photo by Sharon Moorman.

The blue tree centipede. Photo by Sharon Moorman.

This is the smallest of the five, seldom exceeding 3 inches, but still the largest centipede throughout most of its range. It is found through much of the East, from Ohio and Pennsylvania south to Florida and west to eastern Texas. Tree centipedes are also found in Mexico south to the Yucatan Peninsula. As the name suggests, the tree centipede is often an attractive blue-green, with yellow legs and orange fangs. The brightness of the color depends on the location, however, and some are paler than others.

The blue tree centipede is a habitat specialist, living under the bark of rotting trees, often before they have toppled to the ground. I have had the best luck finding them under the bark of pine logs. Because they are such good climbers, they occasionally wind up in buildings where they can cause quite a scare.

Bites from tree centipedes are painful but not much worse than a bee sting. They use their venom, as all centipedes do, to kill prey. Because they prefer to live in rotten pine logs, they may specialize in hunting beetle grubs that eat rotting wood. Like most centipedes, however, data on their feeding habits is severely lacking.

Green-striped Centipede (Scolopendra viridis)

The green-striped centipede is larger, reaching 6 inches or so, and usually pale yellow with a thick green or black stripe running down the back. Other patterns exist, however, and in parts of their range this species can appear more like a tree centipede or a tiger centipede (#4). These are adaptable centipedes, found from Florida west to Arizona, but don’t seem to venture further north than South Carolina.

The green-striped centipede. Photo by Jeff Hollenbeck, licensed under CC BY-ND-NC 1.0.

The green-striped centipede. Photo by Jeff Hollenbeck, licensed under CC BY-ND-NC 1.0.

Green-striped centipedes can live in a variety of habitats but they seem to prefer sandy forests. In Florida they can be found in scrub habitat, but like all centipedes they are not well-adapted to drought, and must stay moist by hiding underground or in rotting logs during the day.

Caribbean Giant Centipede (Scolopendra alternans)

The Caribbean giant is the only one of the Five with the russet-brown, mono-chromatic appearance of a “typical” centipede. It is probably our largest species, with a length easily exceeding 8 inches. However, the Caribbean giant is, as you might have guessed, a tropical centipede, and in the U.S. it lives only in southern Florida. It requires humid habitats, and the best place to find them is in and around the Everglades, in Dade and Monroe Counties.

A certain foreign species, the Vietnamese giant (Scolopendra subspinipes), is easily confused with the Caribbean giant at first glance. That wouldn’t be a concern, except that the Vietnamese giant has already become invasive in Hawaii and — this is just my speculating — is likely to become established in the Everglades at some point in the future. Because it is so large, often exceeding 10 inches, the Vietnamese giant is sometimes sold in the pet trade. Bites from either species are not deadly, but extremely painful.

Tiger Centipede (Scolopendra polymorpha)

A tiger centipede from Arizona. Photo by Sue Carnahan, licensed under CC BY-ND-NC 1.0.

A tiger centipede from Arizona. Photo by Sue Carnahan, licensed under CC BY-ND-NC 1.0.

Like the green-striped centipede, the tiger is a 6-inch-long animal found in a variety of habitats. Unlike the green-striped, this is a strictly western species, found from Idaho south through California into Mexico, and east all the way to Missouri. Its name comes from its color pattern: each segment is orange or yellow with a narrow, dark band.

Giant centipedes often move faster by undulating in a snake-like fashion, taking advantage of their long and muscular bodies. When a tiger centipede does this, the bands appear to “flicker,” rather like the brightly-banded milk snake and coral snake. This can make the centipede more difficult to track visually, and hence more difficult for a bird or mouse to grab.

Tiger centipedes, like their namesake, are voracious predators. They have been seen taking down prey much larger than themselves, including geckos and praying mantises. In turn, tiger centipedes are prey for scorpions, spiders, snakes, and many other predators.

A tiger centipede, fallen prey to a scorpion. Photo by Jasper Nance, licensed under CC BY-NC-ND 2.0.

A tiger centipede, fallen prey to a scorpion. Photo by Jasper Nance, licensed under CC BY-NC-ND 2.0.

Centipedes are adapted to moving fast, and their exoskeletons are thin and flexible. The drawback is that they dehydrate very easily. Although tiger centipedes are found in deserts, they still have to remain underground most of the time to conserve moisture.

Giant Desert Centipede (Scolopendra heros)

If you’ve ever seen centipedes used in a horror movie, they were probably heros*. They are big, reaching 8 inches or more. They are also brightly colored in black and orange — perfect for Halloween!

The Arizona form of the giant desert centipede. Photo by Aaron Goodwin, licensed under CC BY-ND-NC 1.0.

The Arizona form of the giant desert centipede. Photo by Aaron Goodwin, licensed under CC BY-ND-NC 1.0.

Heros are found in the desert Southwest, and color patterns vary by location. In eastern Texas and Oklahoma, they are typically jet-black with a bright orange head and yellow legs. In Arizona (above) they are usually red, with the first and last segments black. In New Mexico and western Texas the pattern is orange with black bands, much like a tiger centipede.

A giant desert centipede. Photo from NMNH Insect Zoo, licensed under CC BY-NC 2.0.

A giant desert centipede. Photo from NMNH Insect Zoo, licensed under CC BY-NC 2.0.

Why have black on just the head and the last segment? This an example of automimicry, in which one part of an animal’s body mimics the other. In this case, the tail-end of the giant desert centipede mimics its head-end. When faced with a giant centipede, predators usually attack the head, hoping to avoid a painful bite. If a predator gets confused, however, and attacks the tail instead, an unpleasant surprise awaits when the true head whips around to greet its attacker.

Centipedes, giant and otherwise, are pretty scary, and I never begrudge people who are afraid of them. Still, centipedes are amazing animals and if you see one, I encourage you to take a closer look. It will teach you, if nothing else, that just because an animal is frightening does not mean it can’t be beautiful.

*There is a centipede in one of the Human Centipede movies. People often tell me this after I tell them I study centipedes, so let me clarify a few things: I don’t know what kind of centipede the bad guy has for a pet. Not because I couldn’t identify it, but because I have never watched those movies and never will. I also don’t want to hear you describe your favorite scene with as many details as possible. Thank you.

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Sea Spiders and the Rise of the Chelicerates

by Joseph DeSisto

Sea spiders are small, eight-legged marine arthropods with a vaguely spider-like appearance: members of the obscure class Pycnogonida. Most of the 1300 or so species are predatory, feeding on jellyfish, sponges, and other soft-bodied marine invertebrates. After eight-leggedness and predatory habits, the similarities with spiders end.

A yellow-kneed sea spider. Photo by Sylke Rohrlach, licensed under CC BY-SA 2.0.

A yellow-kneed sea spider. Photo by Sylke Rohrlach, licensed under CC BY-SA 2.0.

So what exactly are sea spiders? For a long time they were considered to be the most ancient members of an already-ancient group of animals: the Chelicerata, which includes the arachnids and the horseshoe crabs (Dunlop and Arango 2005). These animals are united by their possession of chelicerae, a kind of mouthpart.

Chelicerae are extremely versatile, and in the 450-odd million years they’ve been around, natural selection has resulted in a huge diversity of forms. A spider’s chelicerae, for example, are hollow and capable of injecting venom into prey. Scorpion chelicerae, on the other hand, are smaller and used for chewing up food. Some harvestmen (daddy-long-legs) have long chelicerae with pincers at the end, useful for grabbing prey.

Sea spiders have chelicerae too — sort of. Their mouthparts at least are similar to chelicerae, but because they’ve been subject to hundreds of millions of years of evolution, it isn’t easy to discern their “true” identity. Modern sea spiders have hollow, tube-like chelicerae, which they use to suck out the insides of their prey.

 licensed under CC BY-SA 4.0.

A sea spider using its chelicerae to prey on a hydroid. Photo by Bernard Picton, licensed under CC BY-SA 4.0.

Classification can get complicated. To understand where sea spiders fit into the tree of life, we must ask the question: are sea spider chelicerae “real” chelicerae? That might sound like a silly question — after all, “chelicerae” is just a term we made up. But what we really mean is, are sea spider chelicerae homologous with the chelicerae of arachnids and horseshoe crabs? If they are, then sea spiders and the other chelicerates inherited their mouthparts from the same common ancestor. If not, chelicerae evolved twice: once in sea spiders, and separately in the “true” Chelicerata.

In 2005, Amy Maxmen and colleagues carefully studied the chelicerae of sea spiders and found that they emerged from a different part of the body than in other arthropods. It seemed that in sea spiders, chelicerae emerged from the same segment that contained the eyes (but not mouthparts) in other chelicerates. This suggested that sea spiders were not true chelicerates, but instead formed their own group, which Maxmen et al. (2005) hypothesized to be the oldest living arthropod lineage.

A sea spider -- the red hanging structure contains the mouthparts. Photo by Scott C. France, licensed under CC BY-SA 2.0.

A sea spider — the red hanging structure contains the mouthparts. Photo by Scott C. France, licensed under CC BY-SA 2.0.

In arthropods and other segmented animals, Hox genes are responsible for making sure that all the right body parts develop on all the right segments. It was surprising, then, when a 2006 study found that the Hox genes place chelicerae on the same segments in sea spiders and in arachnids (Jager et al. 2006). Apparently, this segment was shifted backwards in sea spiders, creating confusion.

Over the years, scientists have tried comparing the DNA of many arthropods to try and understand how they are related to one another. One of the most comprehensive studies (Regier et al. 2010) placed sea spiders comfortably within the Chelicerata, as the group’s oldest (i.e., basal-most) lineage. Since then there has been little debate: sea spiders may be some of the oldest arthropods on earth, but they really are chelicerates, after all (Giribet and Edgecombe 2012). That is, until new evidence comes along to shake things up again.

Cited:

Dunlop J.A. and C.P. Arango. 2005. Pyncogonid affinities: a review. Journal of Zoological Systematics and Evolutionary Research 43(1): 8-21.

Giribet G. and G.D. Edgecombe. 2012. Reevaluating the arthropod tree of life. Annual Review of Entomology 57: 167-186.

Jager M., J. Murienne, C. Clabaut, J. Deutsch, H. Le Guyader, and M. Manuel. 2006. Homology of arthropod anterior appendages revealed by Hox gene expression in a sea spider. Nature 441: 506-508.

Maxmen A., W.E. Browne, M.Q. Martindale, and G. Giribet. Neuroanatomy of sea spiders implies an appendicular origin of the protocerebral segment. Nature 437: 1144-1148.

Regier J.C., J.W. Schultz, A. Zwick, A. Hussey, B. Ball, R. Wetzer, J.W. Martin, and C.W. Cunningham. 2010. Arthropod relationships revealed by phylogenomic analysis of nuclear protein-coding sequences. Nature 463: 1079-1083.

Basketballs, Shark Teeth, and Millipedes: Meet the Haplodesmids

by Joseph DeSisto

I feel like I’m on a roll with the whole common-name-inventing thing, so I’m going to have a go at another millipede family: the Haplodesmidae. These millipedes are poorly known, largely because they are often tiny and cave-dwelling. Beneath the microscope, however, they become utterly captivating. The haplodesmids have intricately shaped and textured exoskeletons, appearing almost as if they were crafted by an artist with very tiny instruments. For the purposes of this blog they will be called the “sculptured millipedes.”

For example:

The star-shaped haplodesmid Eutrichodesmus asteroides. Photo from Golovatch (2009b), licensed under CC BY 3.0.

The star-shaped haplodesmid Eutrichodesmus asteroides. Photo from Golovatch et al. (2009b), licensed under CC BY 3.0.

The millipede above has curled into a protective spiral, with its head at the center. The species name asteroides means “star-like” and refers to the shape formed when it spirals.

Here’s another, Eutrichodesmus incisus, newly described in Golovatch et al. (2009a) from remote Chinese caverns:

A preserved specimen of Eutrichodesmus incisus, shown under a scanning electron microscope. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

A preserved specimen of Eutrichodesmus incisus, shown under a scanning electron microscope. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

Notice the way the back plates, or tergites, have bumps and sutures like the surface of a basketball. They even look a little fuzzy, but it isn’t fuzz — each one of those tergites is covered in microscopic spines. Here’s a close look at the junction between a tergite and a prozonite (the part of a segment that goes before/under the tergite).

Tergite and pretergite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

Tergite and prozonite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

The tergite and prozonite have very different textures! Not only is the tergite bumpy, each bump is covered in tiny, finger-like projections or microvilli:

A single bump on a tergite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

A single bump on a tergite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

The prozonite, meanwhile, is covered in tiny spines. If we look even closer we can see that these spines even come in two different shapes, neatly arranged in rows like a shark’s teeth:

The surface of a pretergite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

The surface of a prozonite of E. incisus. Photo from Golovatch et al. (2009a), licensed under CC BY 3.0.

Pretty cool, right? At this point you’re probably wondering why sculptured millipedes look so weird, but I haven’t even shown you the weirdest one. The most bizarre-looking haplodesmid is star-shaped like E. asteroides, but even more so. Also like asteroides, it was only just described in 2009, from a series of Vietnamese caves (Gorovatch et al. 2009b).

The even-more star-shaped Eutrichodesmus aster. Photo from Golovatch et al. (2009b), licensed under CC BY 3.0.

The even-more star-shaped Eutrichodesmus aster. Photo from Golovatch et al. (2009b), licensed under CC BY 3.0.

Back to the obvious question: why are sculptured millipedes so sculptured? It’s an interesting question, but unfortunately not too much attention has been paid to the minute details of these already minute millipedes. In addition to being tiny, sculptured millipedes are also almost always found in caves, which are often remote and difficult to explore.

So, no one really knows why aster is star-shaped, or why incisus has tiny shark-teeth on its body. If I had to guess I would say that aster‘s projections make the millipedes more difficult to swallow, which is one of the reasons millipedes form spirals in the first place.

As for the teeth on the prozonites — I really haven’t got a clue.

The sculptured millipedes, like many invertebrate families, were barely known until a few intrepid taxonomists got to work on documenting the species. Now that this is starting to happen, perhaps we will find out what their strange projections/ridges/teeth/villi are for. I’m betting we will, and I certainly hope so — whatever reason there is, I’m sure it’s amazing.

Cited:

Golovatch S.I., J. Geoffroy, J. Mauries, and D. VandenSpiegel. 2009a. Review of the millipede family Haplodesmidae Cook, 1895, with descriptions of some new or poorly-known species (Diplopoda, Polydesmida). ZooKeys 7: 1-53

Golovatch S.I., J. Geoffroy, J. Mauries, and D. VandenSpiegel. 2009b. Review of the millipede genus Eutrichodesmus Silvestri, 1910 (Diplopoda, Polydesmida, Haplodesmidae) with descriptions of new species. ZooKeys 12: 1-46.

Mossy Millipedes: Meet the Platyrhacids

by Joseph DeSisto

I’ve been wanting to write an article about bryophytes — mosses and related plants — for some time now, ever since I was able to take a course on bryology here at UConn. Conveniently, bryophytes and invertebrates have formed some amazing relationships, giving me the perfect excuse to write about them! Today’s story comes from one such relationship, between several different bryophytes and an unusual millipede in the family Platyrhacidae.

A platyrhacid millipede, Nyssodesmus python, from Costa Rica. Photo by D. Gordon E. Robertson, licensed under CC BY-SA 3.0.

A platyrhacid millipede, Nyssodesmus python, from Costa Rica. Photo by D. Gordon E. Robertson, licensed under CC BY-SA 3.0.

The platyrhacids are just one of many “flat-backed” millipede families in the order Polydesmida, which itself accounts for roughly a third of the known millipede diversity. What makes the platyrhacids a bit odd-looking among other flat-backs is that their back plates (tergites) often have backwards-pointing triangular projections, like the enlarged scales on crocodile backs.

While other millipedes have such projections, and some platyrhacids do not, I’ll still take this opportunity to give platyrhacids a common name: the crocodile millipedes. The name works on a second level: just as crocodiles often have algae growing on their bodies, so does one crocodile millipede have mosses and liveworts growing on its tergites.

First, a primer on mosses and other bryophytes. Just as millipedes are one of the oldest terrestrial invertebrate lineages, so bryophytes are the oldest living land plants. Because of this, they are often regarded as primitive, but in fact bryophytes are both complex and incredibly diverse.

The resilience and diversity of mosses have allowed them to colonize an immense variety of habitats. Photo by Thomas Bresson, licensed under CC BY 3.0.

The resilience and diversity of mosses have allowed them to colonize an immense variety of habitats. Photo by Thomas Bresson, licensed under CC BY 3.0.

Mosses and liverworts grow all over the place, from streams and on the surfaces of tree leaves to bare rock and the sides of houses. Their ability to colonize new habitats is aided by their modes of reproduction: in addition to producing microscopic spores, bryophytes can develop from broken-off fragments. A study by Lewis et al. (2014) suggests that some moss populations owe their existence to tiny moss fragments spread by birds migrating from Alaska to sub-Antarctic Chile!

Now let’s get back to crocodile millipedes. The species in question is Psammodesmus bryophorus, which I’m going to call the mossy crocodile millipede. The mossy crocodile millipede was discovered in a mountain rainforest, high in the Andes of Colombia (Hoffman et al. 2011 — incidentally this was one of the last new millipedes described by Hoffman, one of the greatest millipede taxonomists of all time).

The mossy crocodile millipede, , complete with its bryophyte camouflage. Photo from Martinez-Torres et al. (2011), licensed under CC BY 4.0.

The mossy crocodile millipede, Psammodesmus bryophorus, complete with its bryophyte camouflage. Photo from Martínez-Torres et al. (2011), licensed under CC BY 4.0.

These millipedes are not common — only 22 specimens could be found in the site where they were discovered, the Río Nambi Natural Reserve. Of those, 15 specimens carried at least one, and typically many, moss or liverwort species on their backs (Martínez-Torres et al. 2011). Although moss spores are often spread by insects, for bryophytes to actually be growing on an animal is unusual. Among arthropods, only a few kinds of weevil and one harvestman have been reported carrying just a few moss species.

And yet, Martínez-Torres et al. (2011) report on their specimens “complex mosaics of bryophyte species.” Not only were the millipedes carrying bryophytes, they were carrying ten different species, in five different families! Many of these had never been reported as living on arthropod exoskeletons before, making this a big discovery both for diplopodologists (millipede scientists) and bryologists.

A liverwort growing on one of the tergites of the mossy crocodile millipede. Photo from Martinez-Torres et al. (2011), licensed under CC BY 4.0.

A liverwort growing on one of the tergites of the mossy crocodile millipede. Photo from Martínez-Torres et al. (2011), licensed under CC BY 4.0.

This may not be a totally symbiotic relationship — it’s entirely possible that the mosses and liverworts benefit only by having a growing site, while the millipedes get a nice suit of camouflage. All ten of the bryophytes here are also found either on soil or on the surfaces of other plants. Even so, it’s tempting to think there might be a more complex relationship.

Perhaps the millipedes help the bryophytes disperse their offspring. Or maybe the millipedes deter tiny animals that might eat the mosses, since millipedes are essentially walking cyanide bombs. We can only hope more mossy crocodile millipedes will be found — perhaps then we can get a better idea of what’s really going on in the mountain forests of Colombia.

I know I said only Tuesday and Thursday, but I’m on a bit of a writing binge right now. If you’re someone who gets an e-mail notification every time I post a new article … sorry about that (only a little). When I come down from whatever this is, things will normalize, I promise.

For an excellent blog devoted to bryophytes, be sure to check out Moss Plants and More by Jessica Budke.

Cited:

Hoffman R., D. Martínez, and A.E.F. Daza 2011. A new Colombian species in the millipede genus Psammodesmus, symbiotic host for bryophytes (Polydesmida: Platyrhacidae). Zootaxa 3015: 52-60.

Lewis L.R., E. Behling, H. Gousse, E. Qian, C.S. Elphick, J.F. Lamarre, J. Bêty, J. Liebezeit, R. Rozzi, and B. Goffinet. 2014. First evidence of bryophyte diaspores in the plumage of transequatorial migrant birds. PeerJ 2:e424 doi: 10.7717/peerj.424

Martínez-Torres S.D., A.E.F. Daza, and E.L. Linares-Castillo. 2011. Meeting between kingdoms: Discovery of a close association between Diplopoda and Bryophyta in a transitional Andean-Pacific forest in Colombia. International Journal of Myriapodology 6: 29-36.

Potato Wars: Meet the Gelechiids

by Joseph DeSisto

Today’s story comes from the tiny but remarkable twirler moths, the Gelechiidae. The moths themselves are small and typically brown, attracting little attention, while the caterpillars go by names like splitworm, bollworm, pinworm, tuberworm, and so on, usually referring to the plant tissues they consume.

Human interest in twirler moths, then, is largely focused on their relationships with the plants that both humans and twirlers relish — potatoes, tomatoes, grains, almonds, and many others.

The gelechiid caterpillar Chionodes pseudofondella, freshly coaxed from its silken shelter. Photo by M.J. Hatfield, licensed under CC BY-ND-NC 1.0.

The gelechiid caterpillar Chionodes pseudofondella, freshly coaxed from its silken shelter. Photo by M.J. Hatfield, licensed under CC BY-ND-NC 1.0.

Twirler caterpillars live sheltered lives — they typically either live inside twigs, fruit, leaves, or other plant tissues, or else use silk to roll leaves into shelters. This way the caterpillars can dine in relative peace, with fewer predators able to find and attack them.

The opening to a shelter in mountain mint, made by the caterpillar above.

The opening to a shelter in mountain mint, made by the caterpillar above. Photo by M.J. Hatfield, licensed under CC BY-ND-NC 1.0.

Shelters can be effective against spiders and wasps, but they haven’t stopped humans from using all kinds of strategies, from pesticides to natural predator, to keep twirler caterpillars out of their crops. With good reason — many of these caterpillars cost farmers a huge portion of their annual yield.

Today we are going to focus on one of these moths, the Guatemalan potato moth, Tecia solanivoria (GPM). GPM caterpillars feed underground by boring into a potato and hollowing out a set of tunnels, in which they live until ready to emerge as adult moths. By eating out the inside of the potato, the caterpillars not only damage the crop themselves, they also allow fungi to enter the potato and begin the decomposition process, resulting in a rotten vegetable.

The Guatemalan potato moth's caterpillar, in all its glory. Photo from Hayden et al. (2013).

The Guatemalan potato moth’s caterpillar, in all its glory. Photo from Hayden et al. (2013).

The caterpillars can feed on potatoes both before and long after harvest. As a result, they are easily spread when infested potatoes are shipped across long distances. Although GPM is native to Guatemala, it was first discovered in Costa Rica where it had been introduced in imported potatoes. Entomologists estimate that the introduction occurred in 1970, but the species was not formally described until three years later (Povolny 1973).

Why so long between introduction and description? Here I must editorialize — if Central America had had an active expert in gelechiid taxonomy, the species that was causing so much damage would surely have been discovered much earlier, perhaps even before the species ever left Guatemala! Instead the species was described by a Czech taxonomist, by which time Central American farmers were reporting 20-40% crop losses to the unnamed pest (Povolny 1973). The “outsourcing” of tropical biodiversity research to scientists in first-world countries can have dire consequences.

For reference, here's a map showing Central America and northwestern South America. GPM is native to Guatemala in the northwest, then quickly spread through Central America, Venezuela, Colombia, and Ecuador. Map data: Google, Landsat.

For reference, here’s a map showing Central America and northwestern South America. GPM originated in Guatemala (upper left) and has quickly spread southeast as far as Ecuador and Colombia. Click to enlarge. Map data: Google, Landsat.

Before 1970, the most significant potato-eating caterpillar in Latin America was the potato tuberworm (Phthorimaea operculella — try saying that out loud). Unlike GPM, the tuberworm is a leaf-miner, munching its way through the 2-dimensional world inside leaves. After its introduction to Costa Rica, however, GPM saw a meteoric rise, and quickly stole the show as the most economically injurious caterpillar for Latin American potato growers (Carrillo and Torrado-Leon 2013). In 1983 GPM was accidentally imported (via infested potatoes) into Venezuela from Costa Rica, and South America became the new front in the moth’s conquest. By 1996 the caterpillars had reached Ecuador, and in 1999 a population was even introduced to the Canary Islands off the coast of Northwest Africa.

Managing GPM is an economic necessity. Unfortunately, this can be difficult since once the caterpillar hatches and starts making its tunnels inside a potato, you’ve pretty much lost the potato. Pesticides are generally targeted toward the more vulnerable eggs and adult moths, but these stages are short-lived. Timing is crucial, and only pesticides applied at the right stage will reduce crop losses. Despite this, potato growers frequently err on the side of caution, applying pesticides intensively throughout the growing season (Carrillo and Torrado-Leon 2013). This is not only a waste of money, it can also lead to the moths becoming resistant to the pesticides, not to mention the environmental and human safety consequences of pesticide overuse.

A pinned specimen of the Guatemalan potato moth. Photo from Hayden et al. (2013).

A pinned specimen of the Guatemalan potato moth. Photo from Hayden et al. (2013).

The most effective methods of reducing GPM infestation are not chemical but cultural (Gallegos et al. 2002). Growers can help protect their plants by tilling the soil to break up clumps (havens for moths and eggs), planting their potatoes deeper in the soil, and removing “leftover” potatoes from the soil.

Here’s the twist: under certain conditions, it can actually benefit the farmer to let the caterpillars feed.

In 2010, Poveda and colleagues experimented with GPM abundance in potato fields in Colombia. Surprisingly, fields in which caterpillars were allowed to feed in moderation actually showed higher total yield than when caterpillars were completely excluded. It turns out that when caterpillars feed, the chemicals in their saliva are strewn about the potato, and the plant is able to recognize and react to these chemicals.

Flowers from a potato plant. Photo by Keith Weller, in public domain.

Flowers from a potato plant. Photo by Keith Weller, in public domain.

Each potato plant contains many tubers, the things we call potatoes. If less than 10% of these are infested with caterpillars, the plant compensates by diverting resources to the remaining tubers. The result: a greater number of extra-large potatoes, and an increase in overall yield. Plants with limited caterpillar infestations yielded 2.5 times as much useable potato mass as plants in which there were no caterpillars at all.

The lesson? Plant-insect relationships are complicated, and understanding the subtle details can matter. So can the taxonomy of small, “boring” moths. There are a lot of important things we wouldn’t know about GPM if it weren’t for the hard work and dedication of entomologists from Colombia to the Czech Republic. With invasive pests an increasing problem, we need to make sure to invest in both applied and basic research, and study even the insects that most people would rather ignore.

This post marks the start of a kind of experiment for me. Starting here, I will be posting a new article every Tuesday and Thursday. Here’s the catch: each post will focus on a different family of invertebrates, and I can’t cover the same family twice! The goal is to try and write about as many families as possible, starting with Gelechiidae.

Cited:

Carrillo D. and E. Torrado-Leon. 2013. Tecia solanivora Povolny (Lepidoptera: Gelechiidae), an Invasive Pest of Potatoes Solanum tuberosum L. in the Northern Andes. In: J.E. Pena (Ed.), Potential Invasive Pests of Agricultural Crops (126-136). Boston, Massachusetts: CABI.

Gallegos P., J. Suquillo, F. Chamorro, P. Oyarzun, H. Andrade, F. Lopez, C. Sevillano, et al. 2002. Determinar la eficiencia del control quimico para la polilla de la papa Tecia solanivora, en condiciones del campo. In: Memorias del II Taller Internacional de Pollila Guatemalteca Tecia solanivora, Avances en Investigacion y Manejo Integrado de la Plaga, 4-5 June 2002, Quito, Ecuador pp. 7.

Hayden, J.E., S. Lee, S.C. Passoa, J. Young, J.F. Landry, V. Nazari, R. Mally, L.A. Somma, and K.M. Ahlmark. 2013. Digital Identification of Microlepidoptera on Solanaceae. USDA-APHIS-PPQ Identification Technology Program (ITP). Fort Collins, CO. 7 July 2015 <http://idtools.org/id/leps/micro/&gt;

Povolny D. 1973. Scrobipalpopsis solanivora sp. n. — a new pest of potato (Solanum tuberosum) from Central America. Acta Universitatis Agriculturas, Facultas Agronomica 21(1): 133-146.

The Fork-tailed Dragons

by Joseph DeSisto

Meet Furcula borealis, the caterpillar of the white furcula moth:

Furcula cinerea, the caterpillar of a medium-sized, gray moth. Photo by Joseph DeSisto.

Furcula borealis, the white furcula caterpillar. Photo by Joseph DeSisto.

It’s a weird-looking caterpillar already, but even weirder when viewed head-on:

The fork-tailed dragon caterpillar, Furcula borealis. Photo by Joseph DeSisto.

The fork-tailed dragon caterpillar, Furcula borealis. Photo by Joseph DeSisto.

Like all insects, caterpillars have only six legs, and these are located near the front of the body, just behind the head. The sticky, climbing appendages along the rest of the trunk are not true legs but “prolegs,” which are lost during metamorphosis. In Furcula caterpillars (and the related Cerura, shown below), the last pair of prolegs are modified into long, rigid “tails.”

Cerura scitiscripta, showing six true legs near the head (upper left), four typical prolegs on the trunk, and the special modified pair of prolegs at the rear of the body -- the forked

Cerura scitiscripta, showing six true legs near the head (upper left), four typical prolegs on the trunk, and the special modified pair of prolegs at the rear of the body — the forked “tail.” Photo by Joseph DeSisto.

The furcula moths belong to the strange and beautiful family Notodontidae. These are sometimes called prominent moths, despite mostly being brown, gray, or some combination thereof. Recall, however, that in my last post about caterpillars I referred to notodontid caterpillars as the dragon caterpillars. Furcula, then, are unofficially dubbed the fork-tailed dragon caterpillars.

In case you’re wondering what F. borealis looks like as a moth, here’s an example specimen:

The white furcula moth, Furcula borealis. Photo by Tom Murray, used with permission.

The white furcula moth, Furcula borealis. Photo by Tom Murray, used with permission.

So what is the forked tail for? To find out, we simply tap our little dragon on the head. This is what happens:

Furcula borealis. Photo by Joseph DeSisto.

Furcula borealis, beginning its display. Photo by Joseph DeSisto.

Bright red tentacles begin to emerge from the  modified prolegs. In less than a second they are fully everted:

Don't mess with the fork-tailed dragon! Photo by Joseph DeSisto.

Furcula borealis, tentacles emerging from modified prolegs. Photo by Joseph DeSisto.

The fork-tailed dragon then waves these tentacles about, and even attempts to rub them onto the offending party (i.e., my finger). The “strike” reminds me of a scorpion trying to sting, if scorpions dressed up as clowns and went to birthday parties. After tapping me, the tentacles disappear as quickly as they emerged, while the caterpillar tucks its head and braces itself for another attack.

Furcula borealis. Photo by Joseph DeSisto.

Furcula borealis. Photo by Joseph DeSisto.

In a less dramatic fashion, many insects use eversible organs to rub toxins on their predators. Rove beetles are an example — this explains the way many of them run, with abdomens held high in the air like scorpions. If you grab one, it will use its flexible abdomen to rub a cocktail of nasty chemicals on you, some of which can cause blistering. But in Furcula and Cerura caterpillars, the tentacle-rubbing is actually a harmless show designed to scare off predators. I must admit, were I a foraging bird, I would think twice about attacking a caterpillar with such a bizarre and intimidating display.

And yet, in an ironic twist, these caterpillars are not harmless. If sufficiently disturbed, they can fire off a burst of formic acid — the stuff fire ants sting you with — from glands behind the head. In F. borealis, these are stored in spiky, poisonous-looking projections:

If you're mean enough, this caterpillar might just spray formic acid at you. Photo by Joseph DeSisto.

If you’re mean enough, this caterpillar might just spray formic acid at you. Photo by Joseph DeSisto.

Don’t mess with the fork-tailed dragons!

The Many Uses of Centipede Legs

by Joseph DeSisto

This post started out titled “My Favorite Centipede Genus,” but that could never last. I have too many favorites. Right now, Theatops is my 6th, but things can always shift around. Theatops has no official common name, but in the spirit of this blog, I’m going to make one up right now: the forcep centipedes. I’ll explain why.

Forcep centipedes are not especially diverse, with only six species known worldwide, four of which are strictly North American. They are, however, large and impressive, and reasonably common through much of their range. A week or so ago Derek Hennen sent me a speciment of Theatops posticus, one of two species found in the eastern U.S.:

A Theatops posticus from Ohio, sent to me by Derek Hennen. Photo by Joseph DeSisto.

A Theatops posticus from Ohio, sent to me by Derek Hennen. Photo by Joseph DeSisto.

Modified hind legs are common in centipedes, especially in the scolopendromorphs (centipedes with 21 or 23 pairs of legs). A paper published today in ZooKeys reviewed the uses for hind legs in the family Scolopendridae (Kronmüller and Lewis 2015), which includes some of the most impressive centipedes, i.e., the foot-long giants in the genus Scolopendra.

Their conclusions were that the hind legs of scolopendrids have a wide variety of uses, the least of which is walking. In Scolopendra, the legs are covered in short spines and are used to capture prey, guide courtship, and grapple with predators. After an intimidating display, a Scolopendra can grab onto you with its hind legs, then rear its whole body around to inject venom with its fangs — which are themselves modified legs.

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Figure 2 from the Kronmüller and Lewis paper, showing uses for the spiny modified legs of Scolopendra. The threat display (A and B) would be quite intimidating coming from a centipede that can reach 12 inches or more in length. From Kronmüller and Lewis (2015), licensed under CC BY 4.0.

Hind legs can also mimic antennae, so that predators like birds are tricked into attacking the less vulnerable rear end of the centipede. Attackers are then met with an unpleasant surprise when the real head makes its move! This strategy is most obvious in Scolopendra heros arizonensis, where the trunk is orange but the first and last few segments are jet black. But many non-scolopendrids also have rear legs that resemble antennae, especially the scutigeromorphs or “house centipedes,” whose legs readily detach if they are caught.

Scolopendra heros arizonensis, from the deserts of the southwestern U.S. and Mexico. The

Scolopendra heros arizonensis, from the deserts of the southwestern U.S. and Mexico. The “mimicry” between the front and rear segments might confuse predators into attacking the wrong end. Photo by Aaron Goodwin, licensed under CC BY-ND-NC 1.0.

Scolopendrids can also use their legs to climb, even on the ceilings of caves. Scolopendra gigantea, a South American giant that can reach 12 or more inches in length, has been observed hanging from its rear legs in Venezuelan caves and snatching bats out of the air (Molinari et al. 2005). This phenomenon was even featured in the first episode of David Attenborough’s Life in the Undergrowth television series.

Then there’s the flag-tailed Alipes, which uses its hind legs to make a hissing noise … really you should just read the paper. It’s a peer-reviewed journal article, but it is publicly accessible here and, for the most part, readable by a non-expert.

Miscellaneous scolopendrid rear legs, modified in different ways. The flag-tailed centipede (C) is probably the strangest, and its legs can be rubbed together to make a loud hissing noise. Photo from Kronmuller and Lewis (2015), licensed under CC BY-NA 4.0.

Miscellaneous scolopendrid rear legs, modified in different ways. The flag-tailed centipede Alipes (C) is probably the strangest, and its legs can be rubbed together to make a loud hissing noise. Photo from Kronmüller and Lewis (2015), licensed under CC BY 4.0.

All of this was a very long way of saying that Theatops isn’t really that special … probably. Actually, Theatops was not covered in this paper, since it belongs not to Scolopendridae but to the less-known family Plutoniumidae. And yes, that’s the real name.

In the East we have two species: T. posticus and T. spinicaudus. The main difference between the two is that spinicaudus has a pretty large spine on the last pair of legs, while posticus does not. So, I here propose we call posticus the smooth-tailed forcep centipede and spinicaudus the spiny-tailed forcep centipede.

Smooth-tails are found through most of the eastern U.S., from Connecticut south to Florida and west to eastern Texas (Shelley 2002). A separate population of smooth-tails is found in the West (along with two other Theatops species), in western Arizona and southern California and Nevada, but this may represent a separate species.

Spiny-tails, meanwhile, are abundant but geographically restricted: there are two populations, one in the southern Appalachians and one in the Ozarks (Shelley 2002). Apparently this species prefers mountain habitats, since spinicaudus is not found in the area between the two mountain ranges.*

The forcep-like hind legs of the smooth-tailed forcep centipede, Theatops posticus. Photo by Joseph DeSisto.

The forcep-like hind legs of the smooth-tailed forcep centipede, Theatops posticus. Photo by Joseph DeSisto.

*[Actually, this is why I’m looking for Theatops specimens in the first place — to obtain genetic data so I can figure out how/when they came to inhabit their bizarre geographic ranges.]

The modified hind legs immediately make me think of an earwig, and they appear to be useful for grabbing things — but what are these centipedes grabbing? To start, they certainly do grab the forceps I used to pick them up during my May trip to the southern Appalachians. If you try and pick up one of these centipedes, they will simultaneously grab you with their legs and inject venom with their fangs.

But then, why attack with non-venomous hind legs, when forcep centipedes can and do use their venom-injecting fangs? Perhaps the hind legs give the centipede leverage with which to inflict a longer-lasting, more painful bite. It’s possible, and scolopendrids certainly do it, but I think there may be more to this story.

The business end of Theatops posticus -- the fangs beneath the head pack a healthy dose of venom, used to dispatch prey. Photo by Joseph DeSisto.

The business end of Theatops posticus — the fangs beneath the head pack a healthy dose of venom, used to dispatch prey and make predators cry. Photo by Joseph DeSisto.

The whole last segment of a forcep centipede’s body, including the legs, is heavily protected with extra-thick cuticle. The exoskeleton on the rear legs and segment is about as thick as that around the fangs at the front of the body, which is usually the most heavily protected part of a centipede. I think that Theatops species might use their hind legs to attack dangerous prey — spiders, or maybe even other centipedes. In this way, a forcep centipede can inflict its deadly bite only after the prey has been subdued, so avoiding injury.

It’s only a hypothesis, and one that requires some testing. I have tried feeding smaller centipedes to Theatops, who attacked and fed with gusto, but never used involved their rear legs in the process. So for now, we really don’t know why forcep centipedes have such strange hind legs. All we know is that they are strange, oddly captivating, and will likely remain that way for a long time.

A couple of things. First, I want to thank Derek Hennen, a Masters student at the University of Arkansas, for sending me the specimen photographed here. Actually, this is just one of many centipedes he has sent me! He also has his own blog, Normal Biology, featuring insects, millipedes, and even the occasional centipede.

On July 19 I will be speaking about centipedes, millipedes, and why they’re amazing at the Schoodic Research and Education Center in Acadia National Park (Maine)! This is a public program, part of the bioblitz going on that same weekend in Acadia. If you’re in the area, stop by! More information is available here.

Cited:

Kronmüller, C. and J.G. Lewis. 2015. On the function of the ultimate legs of some Scolopendridae (Chilopoda, Scolopendromorpha). ZooKeys 510: 269-278.

Molinari, J., E.E. Gutiérrez, A.A. De Ascenção, J.M. Nassar, A. Arends, R.J. Marquez. 2005. Predation by giant centipedes, Scolopendra gigantea, on three species of bats in a Venezuelan cave. Caribbean Journal of Science 41(2): 340-6.

Shelley, R. 2002. A synopsis of the North American centipedes of the order Scolopendromorpha (Chilopoda). Memoir of the Virginia Museum of Natural History 5: 1-108.

The Black Corsair, Terror of the Leaves

by Joseph DeSisto

The word corsair originates from the old French word corsaire, used to refer to the Barbary pirates of North Africa from the 16th to 19th centuries. The term later referred to pirates or privateers in general. Today we seldom speak of corsairs — the word has fallen out of use except among entomologists, who use it to refer to a particular subfamily of assassin bugs, the Peiratinae.

These corsairs certainly live up to their name. Just as the Barbary pirates terrorized the Mediterranean, the corsairs are just about every insects nightmare. Like all assassins they are ambush predators, waiting for the perfect moment to strike out and inject acids and enzymes into their prey. The victim is liquefied alive, and then sucked dry until only the crumpled husk of an insect remains.

Below is my personal favorite, the black corsair (Melanolestes picipes). Note the general bad-assery:

The black corsair. Photo by Ilona L., licensed under CC BY-ND-NC 1.0.

The black corsair. Photo by Ilona L., licensed under CC BY-ND-NC 1.0.

Some fun facts about black corsairs:

1) Females hiss during mating. By hiss I really mean stridulate, since they rub their mouthparts together to make the raspy sound (Moore 1961). What message this conveys to the male about his performance — positive or negative — I won’t speculate.

2) They don’t all have wings. With few exceptions (i.e., mayflies) insects don’t develop wings until they become adults. In the case of the black corsair, though, many females reach adulthood without developing wings. Since assassins are ambush predators, they don’t need to do much flying except to find mates. The males get that job.

3) They come in red. Juveniles don’t have fully developed wings, and the exposed abdomen is often reddish until adulthood. In some cases the red is never lost, and the red adults used to be considered a separate species, Melanolestes abdominalis. We now know that the two forms belong to one highly variable species (McPherson et al. 1991).

A black corsair, with the reddish abdomen retained into adulthood. Photo by Mike Quinn, TexasEnto.net, licensed under CC BY-ND-NC 1.0.

A black corsair, with the reddish abdomen retained into adulthood. Photo by Mike Quinn, TexasEnto.net, licensed under CC BY-ND-NC 1.0.

Like all assassin bugs, the black corsair belongs to the insect order Hemiptera, which consists mostly of peaceful herbivores such as stink bugs and aphids. All hemipterans have tube-shaped mouthparts and must injest their food in liquid form. But while plant-feeders have straw-shaped mouths they use to harvest sap, assassins and other predatory forms have mouths shaped like scimitars — i.e., something a pirate might use. One look at a a corsair and you know you are looking at an insect that kills other insects:

The head and prey killing device of the black corsair, Melanolestes picipes. Photo by Brigette Zacharczenko, used with permission.

The head and prey killing device of the black corsair. Photo by Brigette Zacharczenko, used with permission.

Yeah. Not something you want to pick up.

I collected the specimen above in Sumter National Forest, in South Carolina, alongside a ton of other animals with the potential to ruin my day: ticks, scorpions, really big centipedes … enough for a series, really. We’ll see.

Some housekeeping notes. First, I want to thank Brigette Zacharczenko, a PhD student at UConn. She helped me use the Macropod, a very fancy camera by Macroscopic Solutions, to take the picture above. As it happens, she too has a website/blog which features insects and especially caterpillars. You can find that here.

Second, I recently had an article published in Entomology Today, the blog/news site of the Entomological Society of America. It’s about the Migratory Dragonfly Project and how citizen scientists can get involved. You can read that here.

Cited:

McPherson, J. E., S. L. Keffer, and S. J. Taylor. 1991. Taxonomic status of Melanolestes picipes and M. abdominalis (Heteroptera: Reduviidae). Florida Entomologist 74(3): 396-403.

Moore, T. E. 1961. Audiospectrographic analysis of sounds of Hemiptera and Homoptera. Annals of the Entomological Society of America 54(2): 273-291.

Easter Island’s Miniature Wonders of the World

by Joseph DeSisto

Easter Island, a tiny Pacific island more than 2,000 miles off the coast of Chile, is best known for its tremendous stone figures (moai). Hundreds of giant statues, erected by indigenous peoples before European settlers arrived, are scattered all over the island and serve as a major tourist attractions. However, Easter Island is unique not only for its enormous statues, but for its very tiny springtails: specifically, five newly described cave-dwelling species found nowhere else on earth (Bernard et al. 2015).

Fifteen maoi -- on average, each of these is 13 feet tall and weighs 14 tons, but many are much larger. Photo by Ian Sewell, licensed under CC BY 2.5.

Fifteen maoi — on average, each of these is 13 feet tall and weighs 14 tons, but many are much larger. Photo by Ian Sewell, licensed under CC BY 2.5.

Springtails (Collembola) are an ancient group of arthropods, distantly related to insects. They are all tiny, most no larger than a millimeter or so, but they are the most abundant organisms on the planet. This is especially so in soil, with estimates of more than 100,000 individuals per square meter (Ponge et al. 1997). Most springtails are detritivores, feeding on decaying plant matter, although with more than 3,600 described species there is plenty of room for diversity in lifestyle – a few species, for example, are predatory.

Prior to this study, the springtails of Easter Island had never been studied. In an attempt to target new, endemic, and possibly threatened species, Bernard and colleagues explored the caves of the island. They found eight cave-dwelling species of springtails in total. Of these, one was cosmopolitan, and another was known from Hawaii. The remaining six were all endemic to Easter Island, and five of those were new species.

A springtail, Orchesella cincta, from Belgium. Photo by Michel Vuijlsteke, licensed under CC BY-SA 3.0.

A springtail, Orchesella cincta, from Belgium. Photo by Michel Vuijlsteke, licensed under CC BY-SA 3.0.

The ecological history of Easter Island is a sad one. The island was never rich in natural resources to begin with, but when Polynesian settlers arrived and began cutting down forests, the result was ecological (and societal) collapse. When Europeans arrived in the 1800s, the indigenous population had gone through a major decline, and most of the forest was gone. For more than a century Europeans raised sheep on the island, whose grazing kept the forest from returning. Meanwhile, accidentally introduced rats took their toll on native biodiversity.

Today Easter Island is almost entirely grassland, and it is likely that many arthropods, once found nowhere else on earth, are now extinct due to habitat loss (Wynne et al. 2014). Caves are one of the last remaining strongholds for endemic biodiversity, but eventually they too may succumb to habitat destruction and invasive species. Bernard et al. publish descriptions of these five unique springtails not only to add to our understanding of springtail diversity, but also to call attention to the protection needed to preserve Easter Island’s smaller wonders.

Cited:

Bernard, E.C., Soto-Adames, F.N., and Wynne, J. 2015. Collembola of Rapa Nui (Easter Island) with descriptions of five endemic cave-restricted species. Zootaxa 3949(2): 239-267.

Ponge, J., Arpin, P., Sondag, F., and Delecour, F. 1997. Soil fauna and site assessment in beech stands of the Belgian Ardennes. Canadian Journal of Forestry Research 27(12): 2053-2064.

Wynne, J.J., Bernard, E.C., Howarth, F.G., Sommer, S., Soto-Adames, F.N., Taiti, S., Mockford, E.L., Horrocks, M., Pakarati, L. & Pakarati-Hotus, V. 2014. Disturbance relicts in a rapidly changing world: The Rapa Nui (Easter Island) factor. Bioscience 64: 711‒718.

Key-making: Illustrating the Stone Centipedes of New England

by Joseph DeSisto

Have you been waiting on the edge of your seat for an identification key to the New England stone centipedes? Do you often find yourself up late at night, eagerly searching for recent articles in taxonomic journals, only to have your chilopodological hopes dashed?

Well, your wait is (nearly) over! This week I started illustrating a key to the stone centipedes of New England. A total of 18 species are represented, the product of more than a year of relentlessly identifying hundreds upon hundreds of museum specimens, but the key is finally coming! It will be ready to send off to a journal by the end of the semester.

It will be ready. It will be ready. It will be ready.

Fangs! Photo by Joseph DeSisto.

Fangs! Because, fangs! Photo by Joseph DeSisto.

Anyway, I spent today working on line drawings, and I’ve included a few outlines here — note that the images below are not the images that will appear in the key itself. Rather, these are preliminary outlines I have made to provide a template for the final illustrations. They still need a lot of work, including shading.

The outline of the photo from earlier looks like this:

The prosternum (with fangs!) of Bothropolys multidentatus, one of New England's largest and commonest stone centipedes. Illustration by Joseph DeSisto.

The prosternum (with fangs!) of Bothropolys multidentatus, one of New England’s largest and commonest stone centipedes. Illustration by Joseph DeSisto.

Not bad for a first go, huh? Actually it was my fourth or fifth go, but moving on …

How does this work? First, I use a fancy microscope and an extra-fancy image-stacking computer program to make nice clear images of a centipede feature like the one above. Then I print out that photograph, and use a micron pen to outline, directly on the picture, the drawing I want to create. When the photograph is sufficiently defiled by lines, scribbles crossing out lines, and more lines, I put the paper on a light box and copy my outline onto tracing paper.

Then I copy that onto another piece of tracing paper. And another. And another, until finally I have one that’s good enough to look at without cringing.

The centipede from earlier is Bothropolys multidentatus, a common and large centipede in New England. Below I’ve illustrated the pores on the coxae (basal segments) of the 14th pair of legs:

The 14th coxae, viewed from below, of Bothropolys multidentatus. Illustration by Joseph DeSisto.

The 14th coxae, viewed from below, of Bothropolys multidentatus. Illustration by Joseph DeSisto.

The last two illustrations, you may have noticed, are roughly symmetrical. Real specimens are hardly ever that perfect — to make the illustrations look a bit nicer, and fit better on the page, I traced one half first and then traced its mirror image. In other words, the outlines are symmetrical because each side of the line drawing actually shows the same side of the original specimen.

Here’s a special one. This sexy leg belongs to a male Nadabius aristeus, a common but smaller New England centipede. There are two important features I’m trying to show here. First, there are two claws, rather than just one, at the end of the leg. Second, the hairy crest on the tibia is unique to males the genus Nadabius.

One of the terminal legs of a male Nadabius aristeus. Illustration by Joseph DeSisto.

One of the terminal legs of a male Nadabius aristeus. The tarsus/foot is at the bottom. Illustration by Joseph DeSisto.

Female centipedes be like, damn!