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Amphibians are tougher than we think

A few years ago I wrote a blog post about a dream of mine that came true – seeing the gorgeous tree frog Cruziohyla craspedopus in the wild. Even after numerous trips to Ecuador I still consider it one of the best moments I have experienced in the outdoors. Fast forward to this week, I am excited to present a new paper I published about these frogs in Herpetology Notes.

Juvenile fringe tree frog (Cruziohyla craspedopus)

Juvenile fringe tree frog (Cruziohyla craspedopus)

To summarize this already short paper – the fringe tree frog (C. craspedopus), an amphibian often used as an example for species requiring pristine habitats, made itself a habit to breed in human-made infrastructure containing polluted, sewage-like water. And not only that, but the frogs are also perfectly fine with this, recruiting healthy new individuals into the population and returning every year to the same spot for more breeding.

Fringe tree frog metamorph (Cruziohyla craspedopus), still with its tail, climbing out of a septic tank

Fringe tree frog metamorph (Cruziohyla craspedopus), still with its tail, climbing out of a septic tank

Amphibian metamorphs can sometimes look like weird animals... not very froggy

Amphibian metamorphs can sometimes look like weird animals… not very froggy

On the surface this is a simple natural history report that adds to the existing knowledge about the species. However, when you look at the bigger picture there is something else hidden between the lines.

Fringe tree frog metamorph (Cruziohyla craspedopus) in the process of absorbing its tail

Fringe tree frog metamorph (Cruziohyla craspedopus) in the process of absorbing its tail

Remember back in the day when I had to sacrifice amphibians in the name of science? One of the questions that I get asked often is ‘how was this research ever approved by an ethics committee?’ After all, amphibian populations suffer a global decline, caused by various different factors: habitat loss, climate change, diseases, invasive species, etc’. Surely killing hundreds of them for science would seem like defeating the purpose of their conservation. But what if… those amphibians were never meant to be alive in the first place… You see, for the Epomis research we selectively collected tadpoles from areas where they were destined to die. These included flooded vehicle tracks, deep water holes with no climbing surface, and shallow puddles in the process of drying out. We called them “ecological traps”: sites that seemed suitable for amphibian breeding but failed to provide the right conditions to support the growth of tadpoles, or did not hold water long enough to allow for their complete development.

A classic ecological trap for amphibians: a puddle in the process of drying out, containing hundreds of tadpoles. The next day they were all dead. Photographed in Israel

A classic ecological trap for amphibians: a puddle in the process of drying out, containing hundreds of tadpoles. The next day they were all dead. Photographed in Israel

But why do amphibians choose to breed in those dangerous sites in the first place? What can I say, amphibians are idiots. Or are they? Maybe it is just their way of ensuring the survival of their species, and we are interpreting it the wrong way?
The species that breed in ecological traps are usually ones with an explosive breeding strategy: migrating to the breeding sites only for a short period of time during a specific season, and offloading massive amounts of eggs in the water, sometimes up to ten-thousands of eggs per female. With so many eggs being produced by each female, they have nothing to lose. One breeding site may fail to provide the right environment for the developing tadpoles, but others will do fine. Or, some of the tadpoles might grow faster than others and complete their metamorphosis before it is too late.

Three fringe tree frog metamorphs (Cruziohyla craspedopus) at different stages of metamorphosis

Three fringe tree frog metamorphs (Cruziohyla craspedopus) at different stages of metamorphosis

Not too many people are aware that juvenile fringe tree frogs are often active during the early morning hours. Here is one climbing up to the canopy.

Not too many people are aware that juvenile fringe tree frogs are often active during the early morning hours. Here is one climbing up to the canopy.

Back to our fringe tree frogs in Ecuador: the species is an iconic frog, representing a true Amazonian amphibian, with its unique appearance and behavior. To the best of our knowledge it is not an explosive breeder. It is reported to breed in tree holes and in water reservoirs under fallen trees, while spending the rest of its time high up in the thick tree canopy. For many it is considered elusive and hard to find. But in reality these frogs could not care less about the condition of breeding sites or water quality. Just like the aforementioned explosive breeders, while on their search for suitable water reservoirs the frogs can stumble upon something that in their eyes has potential for breeding, and they will test it. This means that to us, it may look like they are choosing the “wrong” place to breed. But what if they are right and we are missing something? Before encountering the frogs described in the paper, I would have sworn that they have no chance at successful breeding in polluted water at an unnatural or disturbed habitat. Not to mention doing it over the course of several consecutive years. And what do you know! They sure proved me wrong and I learned something new. Don’t get me wrong, amphibians still need our constant attention. I am not saying that we should stop our efforts to conserve amphibian species and save them from extinction, but maybe we should cut them some slack. Because even though they are fragile creatures, sometimes they are tougher than we think.

When I think of Cruziohyla craspedopus this is what I imagine: an toy-like animal in a lush, pristine habitat. Well, reality just slapped me in the face.

When I think of Cruziohyla craspedopus this is what I imagine: an toy-like animal in a lush, pristine habitat. Well, reality just slapped me in the face.

Halloween special: My worst bug bite

Last week I gave a seminar in front of med students and doctors at Toronto’s University Health Network about medically significant arthropods. Because I am not a doctor I chose to focus more on the animals themselves, presenting their side of the story and what type of situations bring them to sting or bite humans. The talk went well, I was even able to share my first hand experience with botflies, which triggered some interesting questions from the students. After the talk, one of them approached and asked me – “So, what was your worst bug bite or sting?”
I replied that my body has a severe response to black flies and their bites, swelling like crazy that I can barely recognize myself in the mirror the day after. He seemed satisfied with my reply, however on my way back home it occurred to me that this was not the answer to his question. He did not ask me which bite or sting I disliked the most. He asked me of all the bites and stings that I’ve gotten so far, which one was the worst.
And that is a valid question. I have a history of getting injured while doing all sorts of stuff, and this includes an impressive list of arthropod bites and stings accumulated over the years. But there is one bite that holds the title “the worst”. One bite I will never forget.

Some background: Back in 2007 I took a trip to Ecuador with my colleague and mentor, Alex Shlagman. We worked together at Tel Aviv University’s Natural History Collections (now known as The Steinhardt Museum of Natural History), breeding local and exotic species of arthropods for research, teaching, and display purposes. As the manager of the live arthropods collection, Alex was, and still is, the best arthropods keeper in Israel. On the other hand, I had an extensive travel history under my belt, after crossing South and Central America a few years before. This experience gave me useful insights when tackling the husbandry needs of tropical insects we kept. Nevertheless, it bothered me that Alex, with his vast knowledge of those insects, has never experienced the rainforest and its staggering diversity in person. So I did something crazy and I decided to take him to Ecuador.

One of the places we visited was a biological station close to the Amazon region. Despite the heavy rainfall this area usually gets, it was extremely dry during our visit, which made it difficult to locate animals active during the day – it was just too hot. One afternoon we hung out close to the station’s access road, following leaf-cutter ants and other insects, and taking photos. While tracking leafhoppers I stumbled upon a bush covered with what seemed to be communal assassin bugs. They were quite unique in their appearance, with a shiny lime-green abdomen and black head and limbs. From a distance they looked like spiders.

Assassin bugs in ambush waiting for prey

Assassin bugs in ambush waiting for prey

I took a single photo and then I moved in to do something I knew I shouldn’t – I poked the bug with my finger to force it into a better “pose”.
And it got into a better pose alright, immediately grabbing my finger and punching a hole in it using its thick proboscis. The pain was so sharp that I remember falling backwards and landing hard on my buttocks, while the bug let go and escaped. I sat there, silent, holding my hand with a bitter expression on my face.

Maybe I should elaborate at this point. Assassin bugs are venomous animals. Their venom is rather complex and contains many compounds, some of which has neurotoxic properties that can lead to a systemic response (and so potentially may cause death). Some assassin bugs have venom so powerful that it is often compared to a cobra snake’s venom in its potency, easily causing paralysis in mammals much larger than the small bug. Holotrichius inessi, an assassin bug roaming the deserts of Africa and the Middle East is even known to hunt scorpions, which are feisty venomous animals themselves. That is an extreme example. The truth is, in most cases we do not know enough about assassin bugs and their venom potency. So when bitten, you just don’t know what to expect.

Black sand assassin bug (Holotrichius innesi) preying on a scorpion

Black sand assassin bug (Holotrichius innesi) preying on a scorpion

As I sat there trying to gather my thoughts about what has just happened, I felt numbed by the pain. You know how sometimes when something aches so badly you can feel it pulsating? I did not even feel that. I could not feel anything but pain. I thought to myself, this is it. This is how I go. Alex later told me it was the first time he ever saw me looking confused, like I was watching my life flashing before my eyes. To some extent it really felt this way. I could not speak and I did not want to move (from fear I would worsen my condition). I just wanted this to end. We were essentially in the middle of nowhere, with no one around, so we just waited it out. I cannot remember how long it took, as I really lost the sense of time, but I remember the pain eventually reducing to a dull itch. This is when we got up and left. The itch and stiffness stayed for a few additional days and then dissipated.

Just imagine this probe drilling into your finger. Not exactly fun, I can tell you.

Just imagine this probe drilling into your finger. Not exactly fun, I can tell you.

I always find it a bit funny that my worst bug bite actually is a bug bite. Ever since that trip I have been trying to find that species of assassin bug in my subsequent visits to Ecuador, but I always failed. It is slowly turning into my Moby Dick. The important lesson here is: kids, do not go around poking animals you do not know with bare hands. It has taken me a few more bites and stings until this lesson sank in. Nowadays I am much more careful in the field.
… and I still get bitten and stung.

Compsus: glitter weevils with structural coloration

The insect world is full of great examples for flamboyant insects. From mosquitoes sporting feathery legs and electric blue scales, through the splash of vibrant colors in rainbow katydids, to shiny golden-green orchid bees and their mimics. But none are as dazzling as the glitter weevils of genus Compsus (family Curculionidae, subfamily Entiminae).

Short-snout weevil (Compsus sp.) from Mindo, Ecuador. It is hard to take all these colors in.

Short-snout weevil (Compsus sp.) from Mindo, Ecuador. It is hard to take all these colors in.

Compsus is a large genus distributed mainly in Central and South America, with one species occurring in North America. It contains around 140 species, mostly small to medium sized beetles of 0.5-2.5cm in length. Several species are considered as pests of citrus trees. The adult weevils feed on plant tissue: leaves, flower petals, and pollen, but they will also go for rotting leaves and fermenting fruits. The females oviposit egg masses on the aerial parts of trees. The young legless larvae hatch, drop to the ground, and burrow into the soil where they feed on the roots of the tree. At the end of its developmental stage the larva builds a chamber in the ground and pupates, and it will stay in this state for two months until the adult’s eclosion. Compsus weevils complete their life cycle within 5-7 months.

Another species of Compsus from Mindo, this one has a bit more metallic sheen to it.

Another species of Compsus from Mindo, this one has a bit more metallic sheen to it.

Compsus weevil feeding on rotting plant tissue

Compsus weevil feeding on rotting plant tissue

Freshly-eclosed short-snout weevil (Compsus sp.) use impressive mandibles to break out of the pupal skin. These scissor-like attachments drop later.

Freshly-eclosed short-snout weevil (Compsus sp.) use impressive mandibles to break out of the pupal skin. These scissor-like attachments drop later.

But what makes Compsus weevils so special, as well as other members of subfamily Entiminae, is their eye-catching colors. I would do these beetles a disservice if I didn’t explain where the colors come from, so things are about to get technical. Animal coloration is derived from spectrally selective light reflections on the outer body parts. There are two types of coloration:
1) Pigmentary (or chemical) coloration – occurs when pigments absorb scattered light in a narrow wavelength range. This type of coloration is the most common in animals.
2) Structural (or physical) coloration – achieved by nanometer-sized structures with changing refractive indices, causing coherent light scattering. Structural coloration is less common in the animal kingdom but it is widely encountered as well, and often structural colors are modified by spectrally filtering pigments.

Scales containing photonic crystals on the head of a Compsus weevil

Scales containing photonic crystals on the head of a Compsus weevil

Scales containing photonic crystals on the body surface of a Compsus weevil

Scales containing photonic crystals on the body surface of a Compsus weevil

The structures causing the physical colors are referred to as photonic crystals if they have properties (periodicity) that align with wavelengths of visible light. One-dimensional photonic crystals consist of parallel thin film layers of alternating high and low refractive index materials. These structures create the metallic and polarized reflections of cephalopods skin, the elytra of jewel beetles and scarabs, and the breast feathers of birds of paradise. Two-dimensional photonic crystals are structures with periodicity in two dimensions. An example for two-dimensional photonic crystals in animals would be the coloration of peacock feathers. Three-dimensional photonic crystals have been found in the scales of weevils and other beetles, but also in butterflies like the blue morpho.

Scales containing photonic crystals on the body surface of an Entiminae weevil (Eupholus schoenherri) from Indonesia

Scales containing photonic crystals on the body surface of an Entiminae weevil (Eupholus schoenherri) from Indonesia

Scales containing photonic crystals on the body surface of an Entiminae weevil (Eupholus schoenherri) from Indonesia

Scales containing photonic crystals on the body surface of an Entiminae weevil (Eupholus schoenherri) from Indonesia

Scales containing photonic crystals on the body surface of a Compsus weevil

Scales containing photonic crystals on the body surface of a Compsus weevil

Blue scales on the leg tarsus of an Entiminae weevil (Eupholus linnei) from Indonesia

Blue scales on the leg tarsus of an Entiminae weevil (Eupholus linnei) from Indonesia

In the case of Entiminae weevils, the adult beetles have strikingly iridescent scales, sometimes immersed in pits on the weevils’ elytra and legs. This gives the weevils a festive glittery look, as if they were covered with confetti during a big party. The reason for the bright coloration in weevils is mostly misunderstood. In some ways it may serve as camouflage in green species, but blue-colored species are very conspicuous so it remains unclear whether they advertise something to potential predators. I cannot complain: for me it is always a joy to see the cute Compsus weevils in the wild, even though sometimes it makes you feel like you missed out on a celebration or something.

 

Little Transformers: Dysodius

When I first came up with the idea of Little Transformers, what I had in mind were insects that can masquerade as other objects by changing their appearance or behavior. I consider myself a “mild” Transformers fan: I like the concept of entities taking the form of other things, very much like how mimicry or camouflage work in nature. I have said before that I am not a fan of the current iteration of Transformers, those movies are so bad. However, I am going to take advantage of the upcoming release of the new Transformers movie (and I cannot believe I am using this as my reasoning) to post about yet another Little Transformer. This one does not really transform though, but it sure looks like one of the robots in those films. While I am not sure who is behind the designs for the robots, it was clear right from the start that there is some insectoid perspective to their appearance. I have always preferred the simple “blocky” design of the original cartoon show, but I can see how that would not look very realistic.

As mentioned above, our Little Transformer may not pass as the best example for a mode-changer, but it has an alien-like appearance. Meet Dysodius, a bark bug that belongs to the family of flatbugs, Aradidae.

Bark bug (Dysodius lunatus) crawling on a fallen log. Amazon Basin, Ecuador

Bark bug (Dysodius lunatus) crawling on a fallen log. Amazon Basin, Ecuador

Aradidae are cryptic insects, spending most of their time hidden on or under bark, and inside fallen logs. They feed on fungi: at nighttime both adults and nymphs can be seen aggregating near fruit bodies of mushrooms, sticking their proboscis into the soft flesh. It is a fungi cocktail party, and everyone is invited! Some species of Aradidae even display parental care and protect their offspring. Aradids are incredibly flat, a character that helps them to squeeze into tight crevices and take advantage of the complex habitat that is the bark’s surface, in order to remain hidden from the ever-searching eyes of predators.

Lateral view of a bark bug (Dysodius lunatus). So flat it could sit comfortably inside a paper envelope.

Lateral view of a bark bug (Dysodius lunatus). So flat it could sit comfortably inside a paper envelope.

Members of genus Dysodius are particularly interesting because of the their unique body structure, featuring curved lobes protruding from the pronotum and a crown of “fins” surrounding their abdominal segments. They also have tiny wings, so tiny that it makes me wonder if these wings are truly functional and can create enough force to lift the insect off the ground.

Bark bug (Dysodius lunatus), dorsal view

Bark bug (Dysodius lunatus), dorsal view

Dysodius are also very slow animals. They usually rely on their excellent camouflage rather than speed to avoid threats.

Bark bug (Dysodius lunatus) camouflaged on a fallen log

Bark bug (Dysodius lunatus) camouflaged on a fallen log

Their body surface is rough and often mottled with moss-like splotches. It is also wettable just like tree bark, in other words the colors get darker when getting wet by rain (unlike the water-repellent integument of other bugs), ensuring that the insect is still camouflaged even in rainy conditions.

Bark bugs (Dysodius spp.) from Belize (left) and Ecuador (right) demonstrating different coloration and textures of the body surface.

Bark bugs (Dysodius spp.) from Belize (left) and Ecuador (right) demonstrating different coloration and textures of the body surface.

This begs the question why am I including Dysodius in the Little Transformers series? After all, these insects are already “transformed” and do not change their appearance any further. They already look like a piece of bark. To understand why they are mentioned within these posts, you need to view them from the underside.

Bark bug (Dysodius lunatus), facial view. Am I the only one seeing a robot here?

Bark bug (Dysodius lunatus), facial view. Am I the only one seeing a robot here?

Aradidae, and Dysodius in particular, have one of the most robotic faces in the entire insect world, a face that could easily fit in the current Transformers movie franchise.
If you are not convinced yet, here is a closer look.

Portrait of a bark bug (Dysodius lunatus)

Portrait of a bark bug (Dysodius lunatus)

So if you think the Transformers movies are cool, insects do it better and have been doing it for far longer time. How does that quote from the trailer go?

“A thousand years we’ve kept it hidden. The secret history of Transformers…”

It was hidden all right. But not anymore. I am slowly unearthing this secret, exposing the existence of Transformers right here under our nose. You’re welcome.

Vestria – the katydid that wanted to be a spider

Last week my home country celebrated the holiday of Purim; a holiday of joy, in which people go out to the streets, pretend to be something else by wearing masks and costumes, and exchange gifts. It is kind of like a happy mishmash of Halloween and Saint Patrick’s Day. And what excellent time it is to highlight interesting cases in nature in which one organism pretends to be another. One such story involves a genus of beautiful katydids – Vestria.

Rainbow katydid (Vestria sp.). It is hard to describe how colorful these katydids are. This photo does not do justice to the insect's beauty.

Rainbow katydid (Vestria sp.). It is hard to describe how colorful these katydids are. This photo does not do justice to the insect’s beauty.

When searching for arthropods in the rainforest I made a habit of backlighting leaves with a flashlight to see if there are animals hiding on the side opposite to me. There is always something interesting to find: salamanders, caterpillars, insects infected with parasitic fungi, and even velvet worms. Very often spiders occupy the underside of a leaf by day, waiting for nighttime to resume hunting on the top of the leaf’s surface. Among the most frequently encountered ones are huntsman spiders (family Sparassidae) of the genus Anaptomecus. These are flat, thin-limbed spiders, usually pale green in color to blend in with the leaf they are sitting on, but with a brightly colored abdomen with red and yellow patches. They are extremely fast, and when disturbed they shoot and vanish on the underside of a neighboring leaf.

Huntsman spider (Anaptomecus sp.). Amazon Basin, Ecuador

Huntsman spider (Anaptomecus sp.). Amazon Basin, Ecuador

Huntsman spider (Anaptomecus sp.) hiding under a leaf

Huntsman spider (Anaptomecus sp.) hiding under a leaf

To my surprise, in some of these searches upon shining my light I thought I found a spider at first, but when I turned the leaf I saw a katydid nymph.

Katydid nymph hiding under a leaf. Like Anaptomecus spiders, they too seem to prefer sitting on palm leaves.

Katydid nymph hiding under a leaf. Like Anaptomecus spiders, they too seem to prefer sitting on palm leaves.

With the kind assistance of Piotr Naskrecki I learned that these are nymphs of Vestria katydids, known mostly due to their characteristics as adults (more on that later). Genus Vestria contains four species known from lowland forests of Central and South America, but do not let this low number fool you. There are many more species in need of a formal description, and others awaiting their discovery. In fact, to the best of my knowledge, all the species featured in this blog post are undescribed.

Rainbow katydid nymph (Vestria sp.) camouflaged on a leaf. Amazon Basin, Ecuador

Rainbow katydid nymph (Vestria sp.) camouflaged on a leaf. Amazon Basin, Ecuador

The young Vestria nymphs bear an uncanny resemblance to Anaptomecus spiders. They too are flat, green with similar leg patterns, and have a bright yellow-red abdomen. Their mimicry to the huntsman spiders does not end there: they also share the same behavior of pressing flat against the underside of a leaf when resting, and running to the next leaf when disturbed. And, as I learned the hard way, they can bite. Like most members of tribe Copiphorini, Vestria katydids are packed with powerful jaws, and they will not hesitate to use them when in danger. By the way, these katydids are omnivores, feeding on both animal and plant matter, but they show a strong preference towards live prey, kind of like… well, spiders.

Rainbow katydid (Vestria sp.) feeding on a beetle pupa. When given a chance they will always prefer a protetin-based diet.

Rainbow katydid (Vestria sp.) feeding on a beetle pupa. When given a chance they will always prefer a protetin-based diet.

As adults, the Vestria katydids take a different look completely. They are no longer flat and look like the huntsman spiders. In this stage they are known as rainbow katydids or crayola katydids because of their striking coloration, which is an advertisement of their chemical defense against predators.

A selection of rainbow katydids (Vestria spp.) from the Amazon Basin of Ecuador

A selection of rainbow katydids (Vestria spp.) from the Amazon Basin of Ecuador

When provoked, Vestria katydids curl their body and hunker down, revealing a brightly colored abdomen. They also expose a scent gland from their last abdominal tergum and release a foul odor that is easily detectable from a close distance. Different species of Vestria have different odors, and from my personal experience I can attest that some species smell as bitter as bad almonds while others smell like a ripe peaches. The compounds released are pyrazines, and there is evidence that this chemical defense is effective against mammalian predators such as monkeys. While many katydids have bright aposematic coloration, Vestria species are one of the only examples of katydids successfully deploying chemical defense against predators, making them distasteful. But don’t listen to me, I actually like peaches.

Rainbow katydid (Vestria sp.) displaying defense behavior.

Rainbow katydid (Vestria sp.) displaying defense behavior.

But let’s go back to the spider-mimicking katydid nymphs. As it is often the case in nature, mimicry is not always straightforward. Why would a katydid nymph adopt the look and behavior of a spider? Avoiding predators may be the answer that comes in mind, however it is not that simple to explain. Although the model spiders are venomous, they are easily preyed upon by the predators they share with the katydids – birds, frogs and lizards. So what other benefits come into play here? And is it really a case of mimicry? It is a difficult question to answer, as there are several possible explanations for mimicry in this is a case. To put it into context, on one hand it can be an example of Batesian mimicry, in which one harmless organism adopts the appearance of another that is widely-recognized by predators as toxic, vemonous, or unpalatable, to gain an advantage when confronted with a predator. In other words, the katydids use their mimicry to signal visual predators (such as spiders, mantids) to avoid confrontation with a spider (I discussed a similar case here). On the other hand, it might be a case of Müllerian mimicry, two unpalatable organisms evolve to look similar in appearance, to send the same message to predators and enemies. It is possible that both the Vestria nymph and the spider are signaling that they are fast-moving and can deliver an unpleasant bite when provoked. In addition, both have some sort of chemical defense: the spider is venomous, while the katydid is distasteful. There is also a third option – that this is all coincidental, and it is a case of convergent evolution: the two organisms simply try their best to hide from predators and came up with a similar adaptation to solve a similar problem, without mimicry. Piotr suggested that this is simply a crypsis (camouflage) adaptation for the two organisms. The yellow-red spots can represent leaf damage that is commonly seen on leaves in the rainforest. It just goes to show that in nature things are not always easy to explain, because sometimes they do not fall neatly into our boxes of labeled natural phenomena. What do you think?

Vestria nymphs have beautiful markings on their body, which can assist in breaking the outline of the insect to avoid detection by predators.

Vestria nymphs have beautiful markings on their body, which can assist in breaking the outline of the insect to avoid detection by predators.

In some species the dark markings remain also in the adult stage.

In some species the dark markings remain also in the adult stage.

Smile! You're on katydid camera!

Smile! You’re on katydid camera!

UPDATE (14 May, 2017): Paul Bertner photographed this amazing butterfly pupa in the Chocó rainforest of Ecuador. It bears an unbeatable resemblance to the Vestria katydid nymph!

Riodinid pupa (Brachyglenis sp.) mimicking the Vestria katydid nymph. Photo by Paul Bertner

Riodinid pupa (Brachyglenis sp.) mimicking the Vestria katydid nymph. Photo by Paul Bertner

 

From a blattodean to Nilio beetles

This is the story about how a small blattodean taught me something I did not know about beetles.

While photographing frogs in the Ecuadorian Amazon this past October, I noticed a tiny insect running across the surface of a fallen leaf resting on the forest floor. It had bright colors and looked interesting, so I collected it in hopes to photograph it later. When I finally got to do it, I was struck by its deception. You see, when I initially spotted it I thought it was a beetle. The dome-shaped body and the bright coloration resembled those of some leaf beetle species (family Chrysomelidae), and this insect even moved and walked like a beetle. Nevertheless, a close inspection revealed that its whole body was segmented. This was no beetle. It was a blattodean nymph.

Beetle-mimicking cockroach nymph

Beetle-mimicking cockroach nymph

Beetle-mimicking cockroach nymph. What could be the model species?

Beetle-mimicking cockroach nymph. What could be the model species?

Beetle-mimicking cockroach nymph

Beetle-mimicking cockroach nymph

Blattodeans exhibit some beautiful examples for mimicry, with some species resembling poisonous fireflies and venomous assassin bugs. It should come as no surprise that a blattodean might benefit from looking like a leaf beetle. While many leaf beetles are harmless, some species harbor chemical compounds that make them poisonous or distasteful to predators. Unfortunately, identifying a blattodean from its larval stage is very tricky and close to impossible. I was not able to locate anything that looked like the adult stage of this species. However, when I examined this cute blattodean I remembered that I have seen this color scheme on a leaf beetle before, and after digging in my old photo archive I was able to find the record.

Leaf beetle. Or is it?

Leaf beetle. Or is it?

I took this photo on one of my first visits to Ecuador, over a decade ago. I did not plan to do anything with the photo, but I thought it was a nice-looking leaf beetle and so I snapped a quick photo for my own records. Only I was completely off. This is not a leaf beetle.

Unlike most of its family members that are elongated and dull-colored, Nilio is a genus of darkling beetles (family Tenebrionidae) that bear a striking resemblance to leaf beetles and ladybugs. This resemblance can fool even experienced entomologists. Darkling beetles are well-known for their chemical defense, secreting odorous chemicals that will deter even the most enthusiastic field entomologist. This can explain the blattodean mimicry shown above.

This is not a leaf beetle but a darkling beetle (Nilio sp.)

This is not a leaf beetle but a darkling beetle (Nilio sp.)

After I realized these photos show a species of Nilio, I checked the rest of my photos from the very same trip, and started finding more photos of Nilio species.

Darkling beetle larvae (Nilio sp.) feeding on lichens

Darkling beetle larvae (Nilio sp.) feeding on lichens

Here is a group of larvae on a branch. Nilio larvae are gregarious (live in groups) and feed on epiphytic lichens. If you have ever seen the typical wire-worm larvae of darkling beetles you will understand why I labeled this photo as “chrysomelid larvae” in my archive.

Darkling beetles (Nilio sp.) aggregating next to pupation site

Darkling beetles (Nilio sp.) aggregating next to pupation site

In some species, not only the larvae, but also the adults, are gregarious. Here is a group of adults I found on a tree trunk close to their pupation spot. Like the larvae, these adults were feeding on lichens as well.

A closer look at the Nilio beetles aggregation

A closer look at the Nilio beetles aggregation

As you can see, not all Nilio species have bright coloration as the species shown above. However, even when they are closer to their “darkling roots” they still look more like to members of Chrysomelidae than Tenebrionidae. This all goes to show that even when you are confident about your knowledge of insect taxonomy or biodiversity, nature can still surprise you. I embrace these moments when I am caught unprepared; nothing like learning something new!

Photographing Richardia – a long way to victory

Inside a wooden cabin on the outskirts of the peaceful town Mindo, I am standing on my bed, arms spread sideways. My bright headlamp is on at full output, to overcome the cabin’s dim lights. In a few seconds Javier will step in through the door to pick me up for our night hike in the cloud forest. And he will probably want to know what the hell I am doing.
I am trying to find a 5mm-long fly.
Suddenly, I see it. That tiny spec of an insect. Hanging upside down from one of the ceiling boards. I am reaching out for my pocket to grab a vial. The sound of footsteps climbing up the stairs is getting louder and louder. “Gil, are you there?” Great timing. I must keep my focus or that fly will be gone the moment Javier walks in.
-“Don’t open the door!!!!”

Back in 2015 I contacted Paul Bertner regarding a fly that he photographed in Mindo. It was an antlered fly from the genus Richardia. Ever since I learned about these flies in the introduction course to entomology, I have always wanted to see them in the wild. Males have antler-like projections from their eyes, which are used for pushing an opponent during a combat over territory or a mate. The female Richardia lacks those projections, but is characterized by a telescopic ovipositor at the tip of her abdomen, used for injecting eggs into fruits and other plant tissue. Paul was very kind to share his observations with me, wishing me luck in finding them on my next trip to Ecuador.

This small-antlered fly (Richardia sp.) is feeding on amphibian feces. Many of these flies are attracted to animals' droppings, from which they obtain valuable nutrients.

This small-antlered fly (Richardia sp.) is feeding on amphibian feces. Many of these flies are attracted to animals’ droppings, from which they obtain valuable nutrients.

It took time and determination, but I did manage to find the flies eventually. In the brief window that they were active I took some shots, but I was completely unsatisfied with them. It seems that with Richardia, practice makes perfect. Or should I say, masochism makes perfect. You see, these flies are not only active during a very specific time of the day, on the underside of leaves of specific plants, but they are also extremely skittish. Highly territorial, the antlered males respond to any movement in their surroundings, and that includes a person carrying a big black camera. They take off and vanish almost instantly. And then, in hiding, they wait. What for I am not sure, but only a handful of times the males actually returned to their perch under the leaf. Unfortunately, I had to leave the site before I could take any decent photos. So, the following year I came back to the exact spot again. And there they were in all their splendor! I tried again to photograph the flies in their habitat on the leaves, but since they usually sit on the underside it was tricky. I spent hours with them, only to come up with lousy shots. No, I had to be creative with these Richardia.

Another male Richardia sp. with small antlers

Another male Richardia sp. with small antlers

Richardia flies spend their nights sleeping hidden in folded leaves like this rolled bromeliad leaf. Inside they are protected from many nocturnal predators, such as mantids, ants and spiders.

Richardia flies spend their nights sleeping hidden in folded leaves like this rolled bromeliad leaf. Inside they are protected from many nocturnal predators, such as mantids, ants and spiders.

And so after some thinking I came up with the idea of working at night. The flies are diurnal, in other words they will be less active when it is dark. Or at least that’s what I thought. It was still a very exhausting experience to photograph them (it reminded me of the time I was trying to photograph Sabethes mosquitoes). As I mentioned, Richardia are very responsive and will keep moving and exploring unless they stop to clean themselves up. Every time I had the fly framed and in focus, it would travel to the other side of the leaf. Several times it would escape and I would have to go look for it in the cabin. If you think locating a small flying insect in a messy wooden cabin is easy, think again. I found myself crawling on the furniture and slowly sliding my face against the walls and floors, and when I found the fly eventually I was shocked that I was able to see it at all. I nearly lost my mind trying to photograph it. Will I be defeated by a tiny fly?

Male antlered fly (Richardia sp.). Mindo, Ecuador

Male Richardia fly with impressive antlers

After most of the evening time was lost due to the insect’s aforementioned escapes, I decided to come up with another method to control it during the shoot. It required another pair of hands, so I asked my friend Javier Aznar, who I just met in person a couple of days before, to assist. In fact, without Javier’s help I would probably not get any usable shots. I thank him for putting up with me and for keeping my sanity during those difficult hours. “Nothing is impossible”, he told me. He probably thought I was crazy for spending so much time photographing a single fly. Well, it is somewhat true, if you consider the fact that I came back to Mindo just for that purpose. This time, I am very happy with the photos. There will probably be other chances to photograph Richardia flies, but I got precisely what I came for. And it felt like a small victory.

The antlers are thin projections coming out from below the fly's eyes.

The antlers are thin projections coming out from below the fly’s eyes.

The head of a male antlered fly (Richardia sp.) in all its glory. This is the shot I had in mind!

The head of a male antlered fly (Richardia sp.) in all its glory. This is the shot I had in mind!

Not all Richardia species have antlered males, by the way. Some species have no such ornamentation/weaponry at all, yet I still think they are stunning flies with their colorful eyes, decorated wings and shiny bodies.

Mating richardid flies. This species is antler-less, but nevertheless they are very beautiful.

Mating richardid flies. This species is antler-less, but nevertheless they are very beautiful.

Another group of species have had the head morphology evolving in a completely different direction. Instead of having antler-like projections coming from below their eyes, males evolved wide heads. These flies are sometimes called hammerheads, due to their striking resemblance to hammerhead sharks. They are also often mistaken for stalk-eyes flies, however the latter belong to a separate family of flies (Diopsidae, not Richardidae) distributed mainly in tropical regions of Asia and Africa. The hammerhead Richardia can sometimes be seen on the underside of broad leaves such as those of banana and heliconia plants. Males engage in head-pushing tournaments while a single female usually stands by watching and waiting for the winner to approach. He will then display a short dance, running in circles and waving his decorated wings, before mating with her.

Male hammerhead fly (Richardia sp.). This one was scouting out a female on a nearby leaf.

Male hammerhead fly (Richardia sp.). This one was scouting out a female on a nearby leaf.

Hammerhead fly (Richardia sp.). Mindo, Ecuador

Male hammerhead fly (Richardia sp.) with “demonic” eyes

The female hammerhead Richardia has a less pronounced head

The female hammerhead Richardia has a less pronounced head

If you remember my previous post, Richardia flies are not immune to infections, and they are occasionally found “glued” to the underside of leaves after being killed by an entomophagic parasitic fungus (Ophiocordyceps).

An unlucky Richardia fly infected with Ophiocordyceps parasitic fungus. Mindo, Ecuador

An unlucky Richardia fly infected with Ophiocordyceps parasitic fungus. Mindo, Ecuador

I should mention another fly species, an extreme case of a hammerhead fly. Unlike Richardia, this one belongs to another family, Ulidiidae. Plagiocephalus latifrons is probably the closest neotropical equivalent to the old-world stalk-eyed flies, with a head so wide and so disproportional to the rest of the body that it looks more like someone’s prank than a real living animal.

Male hammerhead fly (Plagiocephalus latifrons), dorsal view. One of the most amazing fly species out there in my opinion!

Male hammerhead fly (Plagiocephalus latifrons), dorsal view. One of the most amazing fly species out there in my opinion!

Male hammerhead fly (Plagiocephalus latifrons), frontal view. I cannot imagine this head being very aerodynamic, but you'd be surprised to hear that they are excellent fliers

Male hammerhead fly (Plagiocephalus latifrons), frontal view. I cannot imagine this head being very aerodynamic, but you’d be surprised to hear that they are excellent fliers

The eyes are so wide apart on the tips of the head, that it makes me wonder what these flies see. I am also curious as to how these flies look like at the exact moment when they emerge as adults from their puparium. Surely this whole elongated head cannot fit inside the compact oval puparium within the last larval skin, so it must get pumped up and expanded right after the fly’s eclosion (the BBC has a nice video showing this in a stalk-eyed fly). I would love to see this process in person one day – there is still so much to discover!

One unlucky earwig

(or why you should not get attached to whatever you encounter in the wild)

Isn’t being outdoors the greatest thing in the world? Surrounded by the soothing beauty of nature, while observing species living together in harmony? It is easy to lose sense of reality sometimes. But things are not always what they seem, and this serenity is often deceiving. We do not like to think about it, but nature is a harsh environment. There is a constant struggle for survival, many animal and plant species compete with each other over resources and breeding space. In fact, many of the animals we humans encounter in the wild are already on their way out of the game, either due to senescence, diseases, pathogens or parasites. I always try to remind myself that if I stumble upon an elusive animal active beyond its normal activity time, and it is not startled by my presence, then something fishy is going on here.

That being said, I admit that many times my sound judgment is clouded by the sheer excitement of finding something I have never seen before. Case in point: During one of my visits to Mindo cloud forest in Ecuador, I came across a beautiful specimen of earwig.

Giant earwig (Allostethus sp.). Mindo, Ecuador

Giant earwig (Allostethus sp.). Mindo, Ecuador

In general, earwigs suffer from a bad reputation, or lack thereof. While many people simply ignore them because they do not find them interesting, others find them terrifying due to their menacing-looking pincers. Nevertheless, these animals are both fascinating and harmless. First, they have interesting behaviors. Pairs often construct a breeding chamber together, and females display maternal care, tending the eggs and baby earwigs until they can fend for themselves.

Giant earwig (Allostethus sp.) guarding the entrance to its burrow. Breeding pairs of earwigs construct such chambers, where the female later cares for the brood. Amazon Basin, Ecuador

Giant earwig (Allostethus sp.) guarding the entrance to its burrow. Breeding pairs of earwigs construct such chambers, where the female later cares for the brood. Amazon Basin, Ecuador

Second, earwigs cannot cause any injury to us. They cannot bite, and they possess no stinger or venom. Some species have an unpleasant odor, but you should not go sniffing animals that sport a pair of pincers anyway… Earwigs are omnivorous, and although they mainly feed on plant matter, they often use their modified cerci (the pincers) to manipulate soft prey such as moths and insect larvae. Earwigs are usually seen crawling on the ground or on plants, clumsily dragging their elongated body. However, they are also good fliers – underneath those square leathery forewings are neatly folded flight wings. During flight they spread like a delicate fan.

Detail of earwig wing. Ontario, Canada

Detail of earwig wing. Ontario, Canada

The earwig I found in Mindo belonged to the genus Allostethus (family Labiduridae). It is a beautiful animal, with a length of up to 35mm, a shiny black body and orange legs, and each of its forewings is decorated with a bright orange patch. I found it active on a mossy tree trunk in broad daylight, something I should have regarded to as suspicious, as earwigs are nocturnal insects. In any case, I did not give it much thought and collected the specimen, hoping I could later get some behavioral shots of it preying.

Giant earwig (Allostethus sp.), what a magnificent beast!

Giant earwig (Allostethus sp.), what a magnificent beast!

However, I waited too long. In the evening the animal stopped moving and appeared dead. I was devastated. It still looked healthy, no signs of injury, starvation, or poisoning. I decided to keep it in the vial and moved on to other work. The next morning I had my first evidence of the culprit – the earwig started to grow some whitish “fur”.

Giant earwig (Allostethus sp.) covered with entomophagic fungus. What a magnificent beast?

Giant earwig (Allostethus sp.) covered with entomophagic fungus. What a magnificent beast?

This was not, of course, fur per se, but small filaments indicating an infection by a parasitic fungus specifically feeding on insects. Parasitic entomophagic fungi (such as Cordyceps and Ophiocordyceps) are extremely common in the tropics. Moreover, they are so diverse that many of their species are host-specific. In other words, a certain fungus species attacks only arthropods from a specific order or family. Typically, the growing fungus inside the still-living arthropod alters its normal behavior, causing it to roam in unusual locations, and often outside of its normal range of activity hours. In many cases the infected animal climbs on nearby tree trunks, branches, or positions itself on the underside of a leaf. This is done to allow better spread of spores from the fungus fruit bodies.

Detail of the fungus feeding on the earwig

Detail of the fungus feeding on the earwig

Seeing that stunning earwig giving in and dying was heartbreaking, but it is important to remember it happens every day in nature. When walking in a tropical forest, there are signs of death by entomophagic fungi all over the place. It is hard to avoid corpses of ants, grasshoppers, moths, and beetles, all with bright fungal horns and tubers sticking out of their bodies. However, it is extremely hard to predict if a living arthropod is already infected with the fungus or not. Many times I have seen insects that behaved like “zombies”, only to later find out that they were harboring a parasitoid wasp or a parasitic worm. Looking for early signs of a fungus infection is trickier, but at least now I am a little bit wiser. I will know what to do the next time I see an earwig climbing up a tree at daytime.

Diaethria – a festive caterpillar with antlers!

In my last trip to the Amazon basin of Ecuador I had the fortune of meeting Paul Bertner, an acclaimed photographer and adventurer. I have been following his image posts and trip reports since I cannot remember when (and you should too!), and was excited to spend some time in the field with him, in hopes of learning some new tricks. It was great fun to discover hidden gems in the rainforest together, while discussing arthropod biology, conservation and photography.

During one of our night hikes we came across a tiny green caterpillar that was resting on a silky retreat on top of a leaf. At first glance it did not look very special, but then I noticed that its head featured two enormous antler-like horns. The horns were almost half the caterpillar’s body length! They were not simple straight horns, but rather complex structures that included many branches and hairs. I recognized the caterpillar as a member of tribe Biblidinae in the butterfly family Nymphalidae, but only later learned that it belongs to genus Diaethria.

Eighty-eight caterpillar (Diaethria sp.) with complex antler-like horns. Amazon Basin, Ecuador

Eighty-eight caterpillar (Diaethria sp.) with complex antler-like horns. Amazon Basin, Ecuador

Despite their small size, Diaethria butterflies are quite well-known thanks to the characteristic pattern on the underside of their hindwings. Circular bands in black and white surrounding black dots, giving the impression of the letters BB, Bd or the the numbers 88, 89, 69 etc’. The common names “88 butterfly” and “89 butterfly” are typically used for species in this genus. They are often seen puddling – an interesting behavior in which butterflies take up minerals from mud, sweat and feces.

Eighty-eight caterpillar (Diaethria sp.) is sometimes seen waving its horns while walking.

Eighty-eight caterpillar (Diaethria sp.) is sometimes seen waving its horns while walking.

Upon seeing the caterpillar I knew exactly how I want to photograph it. I wanted a frontal, head-on photo of the caterpillar’s head with the antlers stretched up in their full glory. What photo is more suitable for the holiday season than a festive caterpillar? Unfortunately, I did not have my high magnification MP-E lens with me (as mentioned, the caterpillar was tiny), so I gently collected it to photograph later. Let me tell you, photographing it was not an easy task. It seems that the caterpillar’s default behavior is to rest face down on the leaf, preventing any view of its antlers other than a dorsal one. It literally took hours to get it to change position, and I had to come up with a creative solution to get something remotely similar to the photo I had in mind.

This deer-mimicking caterpillar wishes you happy holidays and a happy new year!

This deer-mimicking caterpillar wishes you happy holidays and a happy new year!

One question that comes to mind is how do these caterpillars molt with such long head protrusions? Do the horns come out already stretched from the old head capsule or are they compressed as horn “buds” that inflate later? And what are those horns good for? They are most likely an adaptation against predators, but it is hard to say exactly how they are used. They can be used as defense to push away ants from attacking the caterpillar, or maybe the caterpillar drives away parasitoid wasps by waving the antlers from side to side. Hopefully someone will be able to document their function in the future and shed light on these remarkable structures.

 

This leaf got me thinking

I sometimes like to drift away in my thoughts and reflect on my days before becoming a biologist. It is amazing to realize how much I have learned over the years. This is something I think many people take for granted nowadays. We are flooded with easily accessible information on a daily basis. Try to think how many new things you learned just in the last month.
A little over a decade ago, I embarked on my first big overseas trip. Back then I knew close to nothing about Latin America. I had one goal in mind: to see poison dart frogs in the wild. Not too long into the trip I already felt victorious, after spotting some of these frogs in Bolivia and Ecuador. My quest took me to Costa Rica, where I found more of these stunning hopping jewels. Although I was mainly interested in amphibians, I was overwhelmed by the richness and diversity of arthropods. And more interestingly, despite my knowledge and exposure to various insect species, I realized how much I do not know and need to learn.

One such moment occurred when I visited the pastoral town of Monteverde, more specifically the butterfly gardens there. The guided tour I took passed near a moth wall, which was basically a white painted wall with a powerful light source pointing at it during nighttime. This was the first time I have ever seen a light trap. It was packed with hundreds of moth species. I was fascinated. The other visitors – not so much. They were pressing me to leave these “boring brown bugs” so we can head over to the butterflies area. “Just a second” I replied, “there is one moth I have to photograph”.

Leaf-mimicking moth, Monteverde, Costa Rica

Leaf-mimicking moth, from Monteverde, Costa Rica. Amazing camouflage, down to the level of leaf (=wing) damage and asymmetry. Image scanned from an old film slide.

“That’s not a moth” argued one of the visitors, “it’s just a fallen leaf that was blown onto the screen door”.
The local tour guide smiled but kept his silence.
“Well, if it is just a leaf…” I said and stood up, “…why don’t you touch it then?”
Upon being touched, the “leaf” immediately came into life and took off in a slow flight, disappearing into the foliage.

Many insects try to look like leaves. It is one of the most common types of crypsis. Only some of these insects, however, take it to the next level, mimicking not only the shape and color of leaves, but also their texture, tissue damage and even asymmetry. This moth had all of these. For years I have been waiting for an opportunity to photograph such a moth again, and finally, last year, I stumbled upon a similarly impressive species in the Amazon basin of Ecuador.

Leaf-mimicking saturniid moth (Homoeopteryx sumacensis), Amazon Basin, Ecuador

Leaf-mimicking saturniid moth (Homoeopteryx sumacensis) from the Amazon Basin, Ecuador. It was resting on the bathroom floor – I do not think I would be able to see it if it was resting among fallen leaves.

This species does look (and behave) very much like a leaf. Instead of laying flat like most moths, it holds its wings up in a way that creates a three-dimensional appearance. The forewing tips and margins are delicate; they are usually the first part to suffer tears and damage, contributing to the asymmetrical look of the false leaf. I knew immediately that I want to keep this photo for something special, and I decided to share it on the last day of National Moth Week. After posting it, the internet went wild. The photo was shared hundreds of times on social media, sparking discussions about evolution and moth diversity. It encouraged people to post their own photos of cryptic moths; others messaged me that the photo helped them to see the beauty and uniqueness of moths. I could not be happier.

Leaf-mimicking saturniid moth (Homoeopteryx sumacensis), Amazon Basin, Ecuador

From this angle it is easier to see that it is a moth. Leaf-mimicking saturniid moth (Homoeopteryx sumacensis)

It is important to remember though, that this moth is just one small example from a vast world of moths. There are over 150,000 species of moths worldwide, many undescribed, and many more waiting to be discovered. Moths are everywhere. There is more to them than meets the eye. They take many forms, and can sometimes make you doubt yourself. Until that moment in Costa Rica I was not aware these leaf moths existed, and even today I am not certain of their exact species ID*. Even nowadays within the highway of free information, I still have a lot to learn.

The positive feedback this photo received, as well as my orchid bees photo, made me realize also how much I am grateful for all the people who find my content interesting or inspiring. I never mention this, but it gives me a lot of energy. When things get rough, I remind myself that there is at least someone out there who thinks what I do is cool. I want to take this opportunity to thank all my followers, commenters and visitors. I got to know some fascinating people since I started posting. Thank you, everyone.

*UPDATE: This moth has been identified by Vazrick Nazari from the Canadian National Collections as Homoeopteryx sumacensis, a saturniid moth.