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Lungless and happy about it

It is rather amazing that a terrestrial animal as big as this Ringtail salamander (Bolitoglossa robusta) from Costa Rica can spend its entire life without taking a single breath and rely entirely on gas exchange through its skin.

It is rather amazing that a terrestrial animal as big as this Ringtail salamander (Bolitoglossa robusta) from Costa Rica can spend its entire life without taking a single breath and instead relies entirely on gas exchange through its skin.

Of all the organs in my body, the one that I would be most reluctant to part with (perhaps with the exception of my eyes) are the lungs. It seems that we need them more than anything else. True, we need all the other bits, but lungs seem particularly useful. Without them the brain stops working in a matter of minutes, the vascular system loses its main reason to exist, and the biochemical processes in pretty much every cell come to a grinding halt. Like the hideous inflatable Santa in front of my neighbor’s house, the complex edifice of the human body would immediately collapse if the air supply were to be shut off. It seems that if you are a land-dwelling vertebrate you better have lungs, or you are not going to last very long. And yet, defying common sense, there is a group of terrestrial animals that got rid of their lungs altogether, and in doing so have become widely successful, outcompeting their lunged relatives in both the number of species and their collective biomass. They are the lungless salamanders of the family Plethodontidae.

The Redback salamander (Plethodon cinereus), a small, unassuming animal common in the eastern United States, is a marvel of evolution, with physiology that makes our own appear laughably inefficient.

The Redback salamander (Plethodon cinereus), a small, unassuming animal, common in the eastern United States, is a marvel of evolution, with physiology that makes our own appears laughably inefficient.

I thought of them last month, when freakishly warm weather in Boston forced me to clean up the accumulation of dog poop from the front lawn, which in any other year the snow would have mercifully covered up until spring. The unseasonal warmth also woke up a multitude of creatures that should have been fast asleep, including a couple of Redback salamanders (Plethodon cinereus), which I found under a wooden plank in the garden. Despite the ice crystals glistening in the half-frozen soil, they were surprisingly agile. “Agile” is of course a relative term, especially when talking about an animal whose metabolism is entirely dependent on oxygen passively permeating the skin. Nearly 100% of the oxygen intake and excretion of the carbon dioxide takes place on the surface of the skin of these salamanders, with the throat (buccopahryngeal cavity) accounting for an additional, small proportion of the gas exchange (perhaps for this reason lungless salamanders still retain well-developed nostrils.) Clearly, animals that are incapable of taking active breaths, and thus accelerating or decelerating gas exchange at will, cannot be marathon runners, or runners of any kind. And somehow, by employing various degrees of toxicity and the ability to subsist on low-nutrition diet of springtails and mites, lungless salamanders have managed to become the dominant family of amphibians of the Western hemisphere. Nearly 400 species have already been described and new ones are being discovered every year in both the cool, temperate forests of North America, and in the rainforest canopy of the Neotropics. In some places their numbers are staggering. A recent analysis of the population of the Southern Redneck salamander (P. serratus) of the Ozark Highlands in Missouri put their numbers at 1.88 billion (!) individuals, with the biomass equivalent to that of most whitetail deer in that region – that’s 1,400,000 kg (3,086,471 lb) of amphibian flesh.

Among many adaptations to the arboreal lifestyle are the lungless salamanders' pad-like feet. Despite of the overall similarity, this foot shape has evolved independently in different species of the genus Bolitoglossa.

Among many adaptations to the arboreal lifestyle are the lungless salamanders’ pad-like feet. Despite the overall similarity, this foot shape has evolved independently in different species of the genus Bolitoglossa.

Although all members of the family Plethodontidae are entirely lungless, their ancestors were not. What prompted the loss is still a mystery, and two competing theories, neither particularly compelling, try to explain it. According to the older of the two, lungless salamanders originated from a lineage that inhabited cold, fast flowing and well-oxygenated streams of the Cretaceous Appalachia (lungless salamanders still dominate the amphibian fauna of that region). The loss of lungs made them less buoyant and thus more capable of maintaining their position at the bottom of the stream while hunting for prey. But some researchers pointed out the lack of geological evidence for cold, upland environments in the Mesozoic Appalachia. Instead, they argue, lungless salamanders come from oxygen-poor tropical waters, where highly humid terrestrial environment proved to be a better alternative. Once on land, dense vegetation exerted adaptive pressure to evolve small, narrow heads, which in turn prevented the animals from filling their lungs effectively, and leading to the reliance on respiration through the skin. If this sounds sketchy to you, you are not alone. Most herpetologists today lean towards the first explanation, with the added argument that the loss of lungs happened early on in the larval development of the aquatic ancestors of the plethodontids. But the truth is, nobody really knows.

The ability to use a prehensile tail, a rarity in the animal kingdom, is one of the most amazing characteristics of the large, arboreal Ringtail salamander (Bolitoglossa robusta) from Costa Rica.

The ability to use a prehensile tail, a rarity in the animal kingdom, is one of the most amazing characteristics of the large, arboreal Ringtail salamander (Bolitoglossa robusta) from Costa Rica.

What is not in question is the fact that lungless salamanders rule the forests of North, Central, and parts of South America. Larger species tend to be ground-dwelling, whereas smaller ones live high in the canopy. The arboreal salamanders have evolved a number of cool adaptations to such a lifestyle. The Central American genus Bolitoglossa is famous for its lack of distinct fingers. Instead, these salamanders have pad-like feet that help them move on smooth, wet surfaces of rainforest trees. And although feet in all species of Bolitoglossa look similar, they are the result of two very different evolutionary processes. In smaller species, such as the colorful (and toxic) B. mexicana, the digit-less foot is the result of paedomorphosis – a developmental mechanism during which juvenile characters are retained in adult, reproductive animals. In other words, they have baby feet, and they rely on simple surface adhesion to cling to leaves and branches.

Larger species, such as the Costa Rican B. robusta, also have pad-like feet, but underneath the webbing sit fully developed digits and a complex musculature. The central part of the foot can be lifted, thus creating suction, a mechanism similar to that used by marine cephalopods. But wait, there is more. In addition to having suction cups for feet, this salamander has a prehensile, chameleon-like tail, which it uses to save itself from falling off trees. When I first saw one of these animals a few years ago pull this trick high in the branches in Tapanti National Park, I thought I was hallucinating. And the similarity to chameleons does not end there – just like those reptiles, lungless salamanders sport a long, projectile tongue (in one species the tongue is 80% as long as the body, and salamanders are pretty long animals!) They can eject it with an amazing speed, a mere 117 ms, to catch fast moving prey. And this ballistic tongue projection is an order of magnitude more powerful than that of any muscle in any other living vertebrate species.

All this to say that the next time you find a small, curled up salamander under a rock, look at it with a little more respect. This ancient animal can pull off tricks that would put many Marvel Comics characters to shame. Without taking a breath. Ever.

Ringtail salamander (Bolitoglossa robusta) on a tree branch in Tapanti National Park, Costa Rica.

Ringtail salamander (Bolitoglossa robusta) on a tree branch in Tapanti National Park, Costa Rica.

A really cool sequence of a lungless salamander (Hydromantes) using its projectile tongue (BBC).

A new voice in the chorus

A pair of Jumping Bush Crickets (Orocharis saltator) from Massachusetts. Females have long, needle-like ovipositors, which they use to lay eggs deep into the stems of plants.

A pair of Jumping Bush Crickets (Orocharis saltator) from Massachusetts. Females have long, needle-like ovipositors, which they use to lay eggs deep into the stems of plants.

Yesterday evening, right before the weather turned nasty, as I stood on the deck over my garden I suddenly caught a sound wave, one that I immediately recognized but had never before heard around my house. I ran to grab my recorder and was able to capture a snippet of the call. Seeing me pointing my microphone towards his house, a neighbor approached me warily, inquiring if I am trying to find the property line. I explained what I was doing and he left, satisfied in his knowledge that I am just feeble minded, and not trying to sue him for his land.

The call was that of the Jumping Bush Cricket (Orocharis saltator), a species I first encountered a couple of years ago in Cambridge, MA. Since then I have been looking for other places where this pretty animal might live, but never expected to find it in my backyard. It is a species that belongs to the chiefly tropical subfamily Eneopterinae, and makes a fine addition to the chorus of crickets around my house, which now includes 12 species:

Jumping Bush Cricket (Orocharis saltator)
Handsome trig (Phyllopalpus pulchellus)
Say’s trig (Anaxipha exigua)
Carolina ground cricket (Eunemobius carolinus)
Allard’s ground cricket (Allonemobius allardi)
Striped ground cricket (Allonemobius fasciatus)
Two-spotted tree cricket (Neoxabea bipunctata)
Snowy tree cricket (Oecanthus fultoni)
Spring field cricket (Gryllus veletis)
Fall field cricket (Gryllus pennsylvanicus)
House cricket (Acheta domesticus) (introduced)
Eastern ant cricket (Myrmecophilus pergandei)

Sonogram of the Jumping Bush Cricket (Orocharis saltator); click here to listen to the recording.

Sonogram of the Jumping Bush Cricket (Orocharis saltator); click here to listen to the recording.

A male Jumping Bush Cricket (Orocharis saltator).

A male Jumping Bush Cricket (Orocharis saltator).

 

Tough as nails

Vernal pools are unique aquatic ecosystems, fleeting and unpredictable, but rich in animal life.

Vernal pools are unique aquatic ecosystems, fleeting and unpredictable, but rich in animal life.

Last night I finally managed to see the movie “Gravity”, which proves to me incontrovertibly that humans are not meant to stick their noses outside the protective layer of Earth’s atmosphere, despite having developed all kinds of high tech space gear (which, incidentally, seemed to have been designed primarily to kill Sandra Bullock’s character.) But this unexpectedly beautiful movie also made me think of a certain creature, whose amazing survival skills had lead NASA to use it to test the limits of life’s perseverance in outer space, long before somebody finally realized that people floating aimlessly in the cosmic void make for much better television.

To photograph fairy shrimp and other inhabitants of vernal pools directly in their habitat I used a complicated underwater setup with live video feed that allowed me to see what was in front of the lens. When I turned it on I was amazed how much life was there, it was almost as if I suddenly looked at a tiny coral reef.

To photograph fairy shrimp and other inhabitants of vernal pools directly in their habitat I used a complicated underwater setup with live video feed that allowed me to see what was in front of the lens. When I turned it on I was amazed how much life was there, it was almost as if I suddenly looked at a tiny coral reef.

As the first sunny days of March begin to melt away frozen remainders of winter in the northeaster United States, members of an ancient lineage of animals are getting ready to spring back to life. Throughout most of the year their habitat was as dry as a bone, but when the last patches of snow turned into water, leaf-packed depressions on the forest floor suddenly transformed into small, ephemeral ponds. Known as vernal pools, these fleeting bodies of water will be gone again by the time summer comes, but for now they create a unique aquatic ecosystem. Soon, the water is filled with thousands of tiny animals, at first not much larger than the point at the end of this sentence, but within a few weeks reaching the length of nearly a half of a pinky finger. They are the fairy shrimp (Eubranchipus vernalis), members of a group of crustaceans known as branchiopods, animals that were already present in the Cambrian seas half a billion years ago, before any plants even considered leaving water for terrestrial habitats.

Male fairy shrimp have massive, highly modified antennae, which they use to grasp and hold the female during mating.

Male fairy shrimp (Eubranchipus vernalis) have massive, highly modified antennae, which they use to grasp and hold the female during mating.

Looking at the delicate, soft body of a fairy shrimp it is hard to imagine how a lineage of organisms so seemingly fragile could have survived for so long. Take one out of the water, and it is dead within seconds. Let the oxygen level in the pond drop, and the entire population is wiped out. Given a chance, a single fish could probably do away with them all in a day, but luckily fish don’t do well in ponds that last for only a few months of a year. But fairy shrimps’ frailty is an illusion because where it counts they are as tough as nails.

In the northeastern United States several species of salamanders, such as this Spotted salamander (Ambystoma maculatum) from Westfield MA, share vernal pools with the fairy shrimp.

In the northeastern United States several species of salamanders, such as this Spotted salamander (Ambystoma maculatum) from Westfield MA, share vernal pools with the fairy shrimp.

If you live in a place as transient as a vernal pool, here now but gone in a few months, an environment of unpredictable duration and often uncertain arrival, you better have a solid survival strategy to build your life around. First, once the right environment appears, you must develop very quickly and reach reproductive maturity before the changing conditions kill you. Second, you need a method to keep your genetic line alive, even when the only habitat in which you can survive is gone. And third, plan for the unforeseeable cataclysms, such as sudden evaporation of the pool before you are ready to produce a new generation. Because, if you fail on any of these accounts, your species will not last past the first generation. Fairy shrimp, despite their unassuming physique, are master survivalists in the most hostile and unstable of habitats, and execute the three-step action plan flawlessly.

Male fairy shrimp (Eubanchipus vernalis).

Male fairy shrimp (Eubanchipus vernalis) from Estabrook Woods, MA.

As soon as the vernal pool forms, cysts containing fully formed shrimp embryos from the year before break open, and minute, swimming larvae emerge. They immediately start feeding on microscopic algae and bacteria already present in the water, and grow like crazy. During the first few days of their lives, baby fairy shrimp, known as nauplii, increase their length by a third and nearly double their weight every day. In about a month the animals are fully grown. One pair of the males’ antennae develops into giant, antler-like projections that help them catch and grasp their mating partners, while females grow big egg pouches on their abdomens. A few days later females start to lay at the bottom of the pool large clutches of cysts, eggs with embryos already developing inside, and die shortly after. Soon the water level in the pool begins to drop, and by June all traces of the once vibrant aquatic habitat are usually gone.

The body of a fairy shrimp is nearly translucent, which makes them invisible to a predator looking from above.

The body of a fairy shrimp is nearly translucent, which makes them invisible to a predator looking from above.

But inside the cysts hidden under a thin layer of soil the embryos are very much alive. They slowly continue their development, but can remain in the dormant state, out of the water, baking in the sun or being frozen in ice, for many years. Their outer shell is nearly waterproof, and quite sticky. This stickiness explains the sudden appearance of fairy shrimp in the most unexpected places, including old tires filled with water, after hitching a ride on the legs of birds and other animals. These cysts can live through being dipped in boiling water and liquid air (-194.35 °C, or -317.83°F), which is one of the reasons why these organisms are being used by NASA to test the survival of life outside of Earth’s atmosphere.
The following spring, if everything goes as planned, water of the melting snow awakens the dormant embryos, and within a few days they break the shell of their tiny survival capsules. But not all of them. Only a portion of the cysts responds to the first appearance of water, while others continue their slumber. If the pool dries prematurely, as it sometimes happens during a particularly warm spring, all early hatchlings die, and a second batch of larvae will emerge only if the pool fills up with water again. It has been shown that some cysts in a clutch will wait through eight cycles of wetting and drying before finally deciding to hatch. Fairy shrimp have evolved this ingenious strategy of hedging their reproductive bets in response to the erratic nature of their habitat, and it clearly serves them very well.

Fairy shrimp swim upside down, using 10 pairs of legs to propel themselves and collect bits of algae to feed on.

Fairy shrimp swim upside down, using 10 pairs of legs to propel themselves and collect bits of algae to feed on.

Hugewings

The enormous mandibles of a male dobsonfly (Corydalus)look like formidable weapons, but they are not. The males use them only in ritualized combat with other males and are too weak to use them to pinch or hurt anybody.

The enormous mandibles of a male dobsonfly (Corydalus) look like formidable weapons, but they are not. The males use them only in ritualized combat with other males, and are too weak to use them to pinch or hurt anybody (Barbilla N.P., Costa Rica).

As somebody who grew up in Europe I was really hoping that enrolling in a graduate school in the US would give me a chance to see many organisms that are rare or completely absent from the Old Continent. And, sure enough, as soon as I arrived in New England I almost got into a car accident after spotting my first Virginia possum, I giggled like a little girl at the sight of Black vultures feasting on a roadkill (probably a possum), and almost had a heart attack from the excitement of finding my first horseshoe crab on a beach in Connecticut. But nothing could prepare me for what one evening came to the light of the house that I shared with my then girlfriend. It was a creature so spectacular and unlike anything I had ever seen before that it took me a while to even put it in a broad taxonomic context. “It’s a megalopteran!”, I finally managed to exhale. “Oh yeah, a dobsonfly”, said Kristin, “They are pretty neat.”

Female dobsonfly in her natural habitat along a stream in Tapanti National Park in Costa Rica.

Female dobsonfly in her natural habitat along a stream in Tapanti National Park in Costa Rica.

That was my first introduction to the genus Corydalus, a massive creature that fully deserves to be a member of an insect order christened Megaloptera, or Hugewings (I just made this name up, but I think it’s fitting; as far as I know Megaloptera do not have a single-word common name despite being a well-recognized monophyletic lineage). They easily attain a wingspan of 140 mm (5.5″) and in flight are more akin to bats than insects. The dobsonfly that came to our light was a male and thus carried enormous, tusk-like mandibles that gave him a menacing look.

One of the few colorful members of the order Megaloptera, a Costa Rican dobsonfly Chloronia sp.

One of the few colorful members of the order Megaloptera, a Costa Rican dobsonfly Chloronia sp.

But, like so many seemingly dangerous invertebrates, a male dobsonfly could not hurt anybody even if he really tried. The gigantic mandibles are for show only, and the animal barely has enough muscle power to open and close them; actually biting is completely out of the question. Males use these ridiculous implements in largely ritualized combat with their rivals, a slower, weaker version of the jostling display seen in stag beetles. But be careful with dobsonfly females – while the males carry a pair of chopsticks, these have a pair of powerful wire cutters that can easily draw blood from careless fingers. Dobsonflies don’t live long as adults and, other than drinking water or an occasional visit to a flower to sip some nectar, don’t feed, and die within a few days.

A female dobsonfly taking off from a leaf at night in Tapanti National Park in Costa Rica.

A female dobsonfly taking off from a leaf at night in Tapanti National Park in Costa Rica.

The genus Corydalus is represented by 34 species, found mostly in the tropical regions of the Americas, and only the Eastern dobsonfly (C. cornutus) reaches as far North as Canada, while two additional species can be found in the southernmost parts of the US. The mandibles are enlarged in males of most species in this and in a closely related genus Acanthacorydalis from E Asia, although in Costa Rica I once caught a male of another dobsonfly with exaggerated sexual traits, Platyneuromus soror. His head carried two strange plates that reminded me of the facial lobes seen in an old male orangutan. Why they have them is unknown as they do not appear to use them in any way during courtship or mating.

The function of the large lobes on the head of Central American dobsonfly Platyneuromus soror is a complete mystery.

The function of the large lobes on the head of Central American dobsonfly Platyneuromus soror is a complete mystery.

The larvae of dobsonflies are aquatic and are well known to fishermen as hellgrammites (or helgies) – large, wiggly insects that make excellent bait for bass and trout. They are predators of other aquatic insects, such as caddis flies. Interestingly, while most species prefer large, well-oxygenated bodies of water (and thus make good indicator species of water quality), larvae of some hugewing species are capable of developing in such unusual habitats as water accumulated in tree holes or the digestive liquid at the bottom of pitcher plants. Those species that live in seasonal bodies of water are capable of aestivation, burying themselves is mud cocoons to await the return of water (very much like the lungfish). Interestingly, dried larvae of Megaloptera are used in Japanese traditional medicine to treat emotional problems in children, they are also consumed as a snack Zazamushi (not very tasty, according to my friend Kenji).

Hugewings give the impression of being ancient and primordial, and for good reason. They date back to the Permian, and are probably direct descendants of some of the earliest holometabolan insect (insects with the complete metamorphosis). They used to be lumped with the Neuroptera (netwings), but there is good evidence for their status as a monophyletic sister group to the Neuroptera.

Three species of hugewings common in New England.

Three species of hugewings common in New England.

Bog killers

Sphagnum ground cricket (Neonemobius palustris) from Ponakpoag Bog, MA.

Sphagnum ground cricket (Neonemobius palustris) from Ponakpoag Bog, MA.

The one thing about plants that we take for granted is that they cannot really hurt you. Sure, some are full of toxic compounds and can be deadly poisonous if ingested. Others are covered with nasty spines or irritating hairs, and a tree  can fall on your head during windy weather and crack your skull. But we feel pretty secure in the fact that no plant can hunt and eat you. Things would be very different, however, if we weren’t some of the largest animals on the planet.

The call of the Sphagnum ground cricket is a soft, high-pitched trill, which is easy to miss unless your are looking for it. Click here to hear the recording of the call at the natural speed, followed by a fragment slowed down 5 times.

The call of the Sphagnum ground cricket is a soft, high-pitched trill, which is easy to miss unless your are looking for it. Click here to hear the recording of the call at the natural speed, followed by a fragment slowed down 5 times.

I was having these thoughts last Sunday when I went looking for another singing insect, the minute Sphagnum ground cricket (Neonemobius palustris), one of a few species of New England acoustic orthopterans that I had never managed to get a recording of. I decided to try looking for it at Ponkapoag Bog in the Blue Hills Reservation, about 10 miles S of Boston. Almost immediately after stepping on the wooden planks that run through the soggy Sphagnum bog I started hearing the characteristic, high-pitched tinkling of those small crickets. But it took me a while to find one, and I only managed to do so after a considerable amount of crawling on all fours, waving a shotgun microphone to pinpoint the source of the sound. Eventually I located one individual in a sunny spot, deep in a clump of red and green moss. As I was recording his song, I also marveled at the idyllic setting of this species’ home. “What a great place to live for an insect”, I thought, “no predaceous ground beetles, no centipedes, water and food plentiful.” But then I heard behind me somebody say “Look honey, bladderworts! They catch and eat aquatic insects.” Right, I forgot about the killer plants.

Looking like a hungry snake, the gaping mouth of the pitcher plant (Sarracenia purpurea) invites unsuspecting insects to their death.

Looking like a hungry snake, the gaping mouth of the pitcher plant (Sarracenia purpurea) invites unsuspecting insects to their death.

Bogs are strange communities, not quite aquatic, not quite solid ground. The constant presence of low levels of water leaches nutrients from the soil, making the habitat extremely poor in minerals, particularly nitrogen. Some plants can fix atmospheric nitrogen thanks to a symbiotic relationship with cyanobacteria in their root system, but most need to find another way, and some do so by becoming carnivorous. I looked around and just a couple of feet from where my cricket was happily singing sat a gaping mouth of the pitcher plant (Sarracenia purpurea). The plant was half hidden in the moss, the lower lip of its pitcher conveniently at  ground level, its entrance inviting to any cricket looking for a hiding place or something to eat. The bottom of the pitcher was dark with half-digested bodies of insects, a few still floating on the surface. The lip’s surface was covered with backward-pointing spines, making it easy for an insect to walk in, but virtually impossible to leave. It was as if you walked into your local grocery store, only to realize that you are in the Little Shop of Horrors.

Unlucky insects and arachnids being digested in the pitcher.

Unlucky insects and arachnids being digested in the pitcher.

In addition to bladderworts and pitcher plants, Ponkapoag Bog is a great place to see honeydews (Drosera rotundifolia). Unlike pitcher plants, which lure and drown insects, sundews actively grab them with their sticky, glandular tentacles that cover their modified leaves. They mostly catch small midges and gnats, but I saw one plant successfully capture a pretty big damselfly using two of its leaves at once. Of course the insect must first touch the plant, but once it does, it is pretty much doomed as the leaves curl and immediately start digesting the prey. I often complain that our huge body size prevents humans from appreciating most of the richness and beauty of the natural world, but carnivorous plants are another reason to think that maybe it is not such a bad thing after all.

Purple pitcher plant (Sarracenia purpurea) from Ponkapoag Bog, MA. The color of the plant is an indirect indication of the availability of nitrogen – the greener the plant, the more nitrogen is present in its environment. A recent study demonstrated that pollution by synthetic fertilizer makes carnivorous plants less interested in insects and more reliant on nitrogen dissolved in the water.

Purple pitcher plant (Sarracenia purpurea) from Ponkapoag Bog, MA. The color of the plant is an indirect indication of the availability of nitrogen – the greener the plant, the more nitrogen is present in its environment. A recent study demonstrates that pollution by synthetic fertilizer makes carnivorous plants less interested in insects and more reliant on nitrogen dissolved in the water.

The pitchers of S. purpurea are its modified leaves, not flowers. Its true and remarkably beautiful flowers appear in the late spring and, unlike the pitchers, are insect-friendly.

The pitchers of S. purpurea are its modified leaves, not flowers. Its true and remarkably beautiful flowers appear in the late spring and, unlike the pitchers, are insect-friendly.

Sundew (Drosera rotundifolia) from Ponkapoag Bog, MA with two half-digested midges.

Sundew (Drosera rotundifolia) from Ponkapoag Bog, MA with two half-digested midges.

Even an insect as big as a damselfly can fall victim to a sundew.

Even an insect as big as a damselfly can fall victim to a sundew.

Say’s trig

A male and a female of the Say's trig (Anaxipha exigua) from Woburn, MA.

A male and a female of the Say’s trig (Anaxipha exigua) from Woburn, MA.

Yesterday my wife called me – “You need to come to Mahoney’s [our local garden center], there are tree crickets on every Holly bush.” I promptly grabbed a few containers and was there in a matter of minutes. And indeed, the place was resonating with soft, bell-like calls of dozens of crickets, but I did not recognize the species. I spent about 20 minutes looking for them, eliciting confused stares from the staff and customers, but could not locate any singing males. In desperation I shook a few bushes, and eventually a female tree cricket (Oecanthus) flew out of one. But I was not convinced that this was the genus that was singing there; the call was just not very tree cricket-like.

I returned the following evening, armed with a shotgun microphone and headphones, intent on locating the callers. The staff of the center was apparently on the verge of kicking me out after watching me waving the long microphone around the shrubs like some deranged Dumbledore wannabe, but Kristin managed to placate them and so they left me alone. But even with the ability to pinpoint each caller, finding the crickets was very tricky, and it took me almost an hour to finally catch a couple.

The call of the Say's trig (click here to hear it).

The call of the Say’s trig (click here to hear it)

The mystery insects turned out to be not tree crickets but much smaller, and orders of magnitude more agile, Say’s trigs (Anaxipha exigua), named after Thomas Say, the prolific 19th century entomologist and malacologist, and the discoverer of this species. I had never seen a Say’s trig before, and was happy to add both the recording and photos to my database of local orthopterans. Anaxipha is a large genus of the cricket subfamily Trigonidiinae, with 135 described and a bunch of yet undescribed species, found mostly in the tropical and subtropical parts of the globe. The Say’s trig, along with the Handsome trig (Phyllopalpus pulchellus), is one of the few species of the group reaching as far North as Massachusetts. The call of the Say’s trig is an almost pure tune trill, with the loud portion at exactly 7 kHz, and a softer harmonic at 14 kHz (click here to listen to the recording).