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The Plot Thickens: This caterpillar ain’t big enough for the two of us

Some of my favorite insects to find while out in the field are hawkmoth caterpillars, or hornworms (named after the characteristic “tail”). They are big, squishy sausages that often show off dazzling colors, sometimes with interesting anti-predator adaptations like eyespots and mimicry. All these characters make the hawkmoth caterpillar look like a toy just waiting for you to play with. The sad truth is that being big and flashy in the natural world often comes with a price. There is danger lurking in every corner. Despite the bright colors and adaptations, birds and lizards do not hesitate to snatch the caterpillars from branches, pathogens and spores of entomophagous fungi scattered everywhere increase the chance for passive infections, and parasitoids are always on the lookout for chunky hosts for their offspring. And the reality is that many of the caterpillars we get to encounter outdoors are already infected with something. I learned this the hard way: as a kid I used to rear a lot of butterflies and moths collected as caterpillars in the field, and many times I was devastated to witness my cute pets being reduced into a sticky mess while wiggly worm-like creatures emerge from their bodies. Sometimes I wonder how lepidopterans manage to keep their populations stable with so many enemies around.

On one of my visits to the beautiful town of Mindo Ecuador, I came across a young hornworm. Despite finding it at daytime, the caterpillar remained calm (many hornworms do their best to disappear from plain sight during the day) so I decided to photograph it.

A cute hawkmoth caterpillar. See that black spot on the leaf? It is important to our story.

A cute hawkmoth caterpillar. See that black spot on the leaf? It is important to our story.

After taking a few shots I noticed a black splotch in the photo that I didn’t like, so I decided to change the angle of view. Little did I know this was a wasp that just arrived at the leaf to check out the caterpillar. A few photos later its identity became clear: It was a species of Brachymeria, a tiny wasp that belongs to the large parasitoid family Chalcididae.

The hawkmoth caterpillar being visited by a parasitoid chalcidid wasp (Brachymeria sp.)

The hawkmoth caterpillar being visited by a parasitoid chalcidid wasp (Brachymeria sp.)

Chalcidid wasps can be easily recognized by their modified hindlegs that resemble mantids’ raptorial forelegs. The function of these structures is largely unclear. The adult wasps feed on nectar and other liquid foods, and do not use the legs for catching prey. There is a paper describing an interesting behavior in which the females use their legs in fighting over a host’s egg mass. Even more interesting are the last three paragraphs of the paper, with additional examples and hypotheses. It seems like there is no single function for these modified hindlegs and it really depends on the species and its biology. One example really stands out: “The female of Lasiochalcida igiliensis literally jumps into the jaws of antlions and holds the mandibles agape with her hind legs while ovipositing.”

Going back to our little Brachymeria and the hawkmoth caterpillar, at first the wasp just strolled peacefully on the leaf next to the caterpillar, but within a few minutes it hopped, quite literally, on the caterpillar and started walking on it, exploring its body surface while frantically moving its antennae.

The wasp jumped on the caterpillar's proleg and started crawling on its body

The wasp jumped on the caterpillar’s proleg and started crawling on its body

In general, the caterpillar doesn’t enjoy this attention, and often swiftly moves its head backwards in an attempt to drive the parasitoid away. It usually does not work. Once a caterpillar has been spotted and marked by a parasitoid as a host, it will be attacked (here’s a fantastic video showing this behavior, notice that the fly sitting nearby is another parasitoid of hornworms – a tachinid fly!).

A closeup of the parasitoid chalcidid wasp (Brachymeria sp.) as it was walking on the hawkmoth caterpillar

A closeup of the parasitoid chalcidid wasp (Brachymeria sp.) as it was walking on the hawkmoth caterpillar

As I was taking photos of the tiny wasp antennating the caterpillar, from the corner of my eye I noticed a bright yellow object flashing in. A second wasp, a golden Conura species, swooshed into the scene and started harassing the busy Brachymeria wasp.

While the Brachymeria was busy exploring the caterpillar, another wasp (Conura sp.) rushed in to fight for it

While the Brachymeria was busy exploring the caterpillar, another wasp (Conura sp.) rushed in to fight for it

For a short while, the Conura striked from above repeatedly, yet the Brachymeria stood her ground. Eventually the Conura got fed up and attempted to grab onto the other wasp and pull her away from the host. After several tries she succeeded, and the two started swirling in the air, before the Brachymeria returned to her business on top of the caterpillar. The golden wasp did not give up and returned for a second attack and then a third.

The two chalcidid wasps (Brachymeria sp. and Conura sp.) fighting over the host. This was taken moments before the Conura grabbed the other wasp's head and dislodged it from the caterpillar.

The two chalcidid wasps (Brachymeria sp. and Conura sp.) fighting over the host. This was taken moments before the Conura grabbed the other wasp’s head and dislodged it from the caterpillar.

This was very exciting to watch, but to be honest I was waiting eagerly to see if the wasps would use their modified hindlegs during the fight. Unfortunately, I was not able to detect any special maneuvers that involved grabbing with those legs.

Why did this happen? There are several possible explanations. The simplest one is that there is a shortage of caterpillar hosts and the two wasps are competing for the same source of food for their larvae. However, an alternative explanation suggests that the caterpillar has already been infected with a parasitoid before the first wasp found it. Many chalcidid wasps are hyperparasitoids – they do not feed on the big hosts (the caterpillar) directly, but instead attack larvae of other parasitoids already feeding inside the host. In other words they are parasitoids of parasitoids.
Parasitoidception.
Watch this excellent video explaining the complex relationship between several wasp species living on a tobacco hornworm:

This can explain the intense antennation performed by the Brachymeria wasp on the caterpillar for a long period of time. Maybe the wasp was trying to determine if there are parasitoid larvae already present in there. One of the most common sights when it comes to infected hawkmoths is a caterpillar with a cluster of white silk cocoons dangling from its body. Those cocoons belong to braconid wasps, and there is a good chance that the Bracymeria wasp was after their larvae, as some species of in the genus are parasitoids of Braconidae. The golden Conura wasp could then compete for access to those parasitoid larvae or even go after the Brachymeria larvae. It can get pretty complicated with chalcidid wasps.

Hawkmoth caterpillar with cocoons of a braconid parasitoid wasp. The caterpillar is still alive, and can move its head to deter predators like ants and other parasitoids from approaching the developing wasps.

Hawkmoth caterpillar with cocoons of a braconid parasitoid wasp. The caterpillar is still alive, and can move its head to deter predators like ants and other parasitoids from approaching the developing wasps.

So who won in the end? The wasp that was more persistent. At the end of the fight the black Brachymeria wasp was nowhere to be seen, and the golden Conura wasp took over the caterpillar and started antennating it.

The winning chalcidid wasp (Conura sp.) with its hawkmoth caterpillar prize

The winning chalcidid wasp (Conura sp.) with its hawkmoth caterpillar prize

The interesting thing here is that members of genus Conura are usually associated with butterfly and moth’s pupae, yet the wasp here decided to chase off a competitor and take over a caterpillar.

Chalcidid wasp (Conura sp.) on a swallowtail butterfly pupa

Chalcidid wasp (Conura sp.) on a swallowtail butterfly pupa

Chalcidid wasp (Conura sp.) on a swallowtail butterfly pupa. This innocent face hides a dark secret.

Chalcidid wasp (Conura sp.) on a swallowtail butterfly pupa. This innocent face hides a dark secret.

Unfortunately, I had to leave the scene to catch a bus so I could not continue following this interaction. Without further observations, it is difficult to say with certainty what exactly was going on between the two wasps and the hawkmoth caterpillar. Parasitoids are so diverse, and many species have such complex biology. Even though several chalcidid wasp species are being studied closely as potential biological control agents, there are far more species out there about which we simply don’t know enough!

 

The Plot Thickens: Staring into the eyes of a dying Cephalotes

If you are an entomologist or an insect enthusiast, it is highly probable that you like ants. It is hard not to be impressed with their diversity, abundance, complex social structure and behaviors, as well as their interactions with other organisms. Ants are everywhere and do almost anything you can think of. To most people however, ants could not be any less exciting. They are often seen as a generic insect, with a relatively uniform appearance. They always show up when unwanted, find their way into our homes, take refuge in dark and hard to reach corners, and steal our food.
I like ants. I think they are fascinating creatures. But every now and then I find myself talking people into looking beyond “that boring-looking ant”, to try and catch a glimpse of their busy life. It is not always easy to communicate ants to the public (which is why I praise myrmecologists – people who study ants for a living), however I find that it is quite easy in the case of one ant genus in particular: Cephalotes.

Turtle ant (Cephalotes atratus) from the Ecuadorian Amazon

Turtle ant (Cephalotes atratus) from the Ecuadorian Amazon

Cephalotes is a large genus of arboreal ants found in the neotropics. There are over 130 species, all inhabit tree hollows or utilize cavities in other plant tissues. Looking like they were designed by someone with overflowing imagination, they easily come off as cute. Their flattened head and armored body, often decorated with long sharp spines for protection, their thick legs and perfectly round abdomen, along with their matte color finish, give them the appearance of a plastic toy. In addition, Cephalotes ants move relatively slowly and cannot bite or sting, making them user-friendly. Can you ask for a more perfect ant?

The queen turtle ant (Cephalotes atratus) is bigger and bulkier than her workers. She also lacks the defensive spines.

The queen turtle ant (Cephalotes atratus) is bigger and bulkier than her workers. She also lacks the defensive spines.

Turtle ant worker (Cephalotes atratus) foraging on a mossy tree trunk

Turtle ant worker (Cephalotes atratus) foraging on a mossy tree trunk

They are commonly known as turtle ants, but also got the name gliding ants, thanks to their incredible ability to parachute from high in the canopy and land back on the trunk of their home tree. Their unique body structure and flattened legs allow them to slow down and change their course while falling (some spiders can do the same, by the way). In some species the soldier cast evolved a large head to function as a living door, plugging the entrance to the nest.

Turtle ant soldier (Cephalotes sp.) from Colombia, showing a heavily armored body and a massive head

Turtle ant soldier (Cephalotes sp.) from Colombia, showing a heavily armored body and a massive head

The same turtle ant soldier (Cephalotes sp.) from the previous photo. These ants are built like tanks.

The same turtle ant soldier (Cephalotes sp.) from the previous photo. These ants are built like tanks.

In regards to interspecific interactions, Cephalotes ants are often seen tending sap-sucking hemipterans such as membracids and small fulgorids to gain access to sugary secretions from those insects. They also act as the model in a mimicry complex, where crab spiders masquerade as the ants in order to sneak up and prey on them.

Cute Cephalotes workers visiting a camouflaged fulgorid planthopper nymph

Cute Cephalotes workers visiting a camouflaged fulgorid planthopper nymph

Portrait of a turtle ant (Cephalotes atratus). How can you not fall in love with them?

Portrait of a turtle ant (Cephalotes atratus). How can you not fall in love with them?

Did I mention they are cute? I have written before that you should never become too attached to insects you encounter in the field. And as much as I love the adorable Cephalotes ants, it is important to remember that there are many dangers lurking for them in the forest. During my recent trip in Colombia, I stumbled upon a Cephalotes nest in a tree outside my room. The ants were very active and did not present good photographic opportunities.

Turtle ant (Cephalotes sp.) from Colombia. How adorable!

Turtle ant (Cephalotes sp.) from Colombia. How adorable!

One of them however, stood out among the rest. There was something different about its behavior. This worker moved franticly in what appeared to be an aimless run. It did not follow the other workers, and seemed more interested in reaching a higher spot on the tree. I collected the ant for a closer look, and once I inspected her carefully I believe I found the culprit for her unusual behavior. This ant had a reddish abdomen, as opposed to the black abdomen of her sisters. The red color, coupled with erratic behavior suggests this worker has been infected with a parasite, a nematode worm.

Turtle ant (Cephalotes sp.) infected with a parasitic nematode worm, showing a swollen red abdomen. Compare to the healthy worker in the previous photo.

Turtle ant (Cephalotes sp.) infected with a parasitic nematode worm, showing a swollen red abdomen. Compare to the healthy worker in the previous photo.

The parasitic worm lives and breeds inside the body of birds, which spread the worm’s eggs in their droppings. The ants collect nutrients from the bird droppings (along with the eggs) and feed them to their larvae, where the worm matures. In order to complete its life cycle the parasite needs to return into a bird’s body, so it changes the host ant’s appearance to look like a ripe red fruit, and causes it to climb higher on the tree to become more accessible to hungry birds. As much unique character this worker ant might have had, the sad truth is that it was destined to die prematurely. And there was nothing I could do about it. There is a great lesson here – sometimes, the raw essence of nature is difficult to take in. We would like to see it as a peaceful place where all the animals and plants live together in harmony. But the reality is that nature is harsh. It is full of conflict, violence, disease, and death. And we must accept it as an integral part of the world we live in.

Cephalotes ants offer a great opportunity to peek into the life of a small insect and learn about its survival (as well as failure) in various habitats. Before I end this post, there is one thing I would like clarified – going back to their name, why did Cephalotes get the name turtle ant, whereas some leaf beetles were named tortoise beetles? Is there any justification for the turtle designation when it comes to the ants? After all, both insects are terrestrial. If there is an etymologist in the audience, maybe you can help the entomologist?

 

Little Transformers: Forcipomyia, the midge that turns into a balloon

It is time to introduce another Little Transformer! I know what you are thinking. Am I ever going to run out material for these blog posts? Maybe. Probably not. As long as there are arthropods around, their life history and morphological diversity guarantees that I will always find examples for interesting deceptions and transformations. Up until now I mostly focused on animals that can change form quickly, assuming the appearance of something else as a defense response against predators and to avoid detection. The case presented in this post is a little different because it does not follow a quick change of form, but rather a slow one, over the course of a life stage. I should be cautious here, because under this definition every insect that goes through complete metamorphosis from larva to adult can be considered a Little Transformer (butterflies, beetles etc’). Even amphibians fall under this loose definition. And to some extent they ARE transformers, because the changes they go through during development are extreme. But this is not the topic for this series of posts. When I talk about a big change happening within a life stage, I mean that the animal starts as one thing, and by the end of the stage its appearance and function has changed into something else completely. And no example is better to show this than the parasitic midges of the genus Forcipomyia.

Biting midge (Forcipomyia sp.) feeding on the hemolymph of a moth caterpillar. Photographed in Belize

Biting midge (Forcipomyia sp.) feeding on the hemolymph of a moth caterpillar. Photographed in Belize

Here is the Forcipomyia midge with the whole caterpillar to give a better sense of scale

Here is the Forcipomyia midge with the whole caterpillar to give a better sense of scale

Forcipomyia is a large genus in the midge family Ceratopogonidae, with a worldwide distribution and diverse habitat preferences. There are now over 1,000 described species of Forcipomyia. The adults of some species are known as important pollinators of cacao and other plants of economic importance in tropical and subtropical areas. However, many species in the genus are blood-feeders, somewhat characteristic to ceratopogonids as the common name to the family suggests (biting midges). These parasites have interesting relationships with different insect hosts, and they can be found feeding on the hemolymph (insect blood) of grasshoppers, katydids, stick insects, butterflies, true bugs, and even skittish dragonflies. In fact, these interactions are so fascinating and overlooked, that only after spending some time in the field one can notice the midges have a preference for certain host species to feed from.

Sometimes the biting midges sneak into the photo without me noticing. I photographed these mating grasshoppers (Cloephoracris festae), but they have an accompanying Forcipomyia. Can you spot it?

Sometimes the biting midges sneak into the photo without me noticing. I photographed these mating grasshoppers (Cloephoracris festae), but they have an accompanying Forcipomyia. Can you spot it?

But let’s go back to the transformation they go through, because in one group of species, subgenus Microhelea, it is truly remarkable. The female Forcipomyia midge begins her adult stage with an active lifestyle. She flies about in the forest, feeding on nectar from small flowers. As days go by, she starts craving for blood and search for insects to bite. When she locates her preferred host, using her serrated mouthparts she proceeds to bite it in an area that has soft tissue: antennae, legs joints, wing veins, or between body segments. Once she found the right spot that will fulfill her dietary needs, the female midge attaches to it firmly, and… doesn’t let go, thanks to specialized claws on her feet. She sucks and gulps the insect’s blood, filtering the nutrients and secreting the excess fluids as clear droplets.

Tick fly (Forcipomyia sp.) feeding on the hemolymph of a walking stick

Tick fly (Forcipomyia sp.) feeding on the hemolymph of a walking stick

The midge stays attached like this for quite a while, and soon this sessile lifestyle starts taking its toll on the small parasite. She starts to put on weight. Then, she usually losses her wings – she will not need them anymore because the added mass from the developing eggs prevents her from taking off.

Female Forcipomyia swelling while feeding. She lost her wings but can still use her legs to hold firmly onto the host

Female Forcipomyia swelling while feeding. She lost her wings but can still use her legs to hold firmly onto the host

Forcipomyia getting fatter... but not quite there yet

Forcipomyia getting fatter… but not quite there yet

As she continues to swell like a grapefruit, the Forcipomyia midge also losses the ability to use her legs. She does not need to leave anyway, but she is so bloated that she cannot even hold onto the body of the host, and the only thing keeping the two connected are the midge’s mouthparts.

Female tick fly (Forcipomyia sp.) at the final stage of feeding. Her legs released their grip on the host and at this point the midge has fully transformed into a passive parasite that looks like a balloon.

Female tick fly (Forcipomyia sp.) at the final stage of feeding. Her legs released their grip on the host and at this point the midge has fully transformed into a passive parasite that looks like a balloon.

Stick insect (Pseudophasma bispinosum) carrying tick flies (Forcipomyia sp.) at different stages of feeding. Photographed in Ecuador

Stick insect (Pseudophasma bispinosum) carrying tick flies (Forcipomyia sp.) at different stages of feeding. Photographed in Ecuador

At this point, the engorged biting midge is no different than a tick, and indeed many refer to these parasitic Forcipomyia as tick-flies. Sometimes I like to imagine these fat dipterans disconnecting from their host and floating upwards like a balloon filled with helium, reaching above the forest canopy and flying into space. In reality, the exact opposite happens. The Forcipomyia female eventually leaves the host and drops to the ground, where she lays her eggs and finishes her role. And the male Forcipomyia? They are mostly unknown. Because males are never found feeding on insect hosts, it is safe to assume that they do not feed on blood, and prefer to keep a vegan diet of sweet nectar.

An engorged female tick fly (Forcipomyia sp.) after dropping from its host

An engorged female tick fly (Forcipomyia sp.) after dropping from its host

What about the larvae, are they parasites too? The majority of the research on biting midges has focused on the adults, due to their economic and medical significance, as well as their important role in aquatic ecosystems. Larvae of most ceratopogonids are unknown because finding them in their natural habitats can be challenging. They usually inhabit aquatic and semiaquatic habitats, but in the case of Forcipomyia the larvae are terrestrial and prefer to feed on moist detritus and organic matter under bark or in moss. In some species they feed on algae.

This stick insect is staring at me with tired eyes. I wonder if it is aware of the two hitchhikers it is carrying?

This stick insect is staring at me with tired eyes. I wonder if it is aware of the two hitchhikers it is carrying?

With so many aspects of their life history still unknown, and especially due to their ecological and economical importance, you would expect to see more active research on Forcipomyia. The bad news is that there is not enough research going on. A few years ago, I approached Dr. Stephen Marshall, a dipterologist from University of Guelph, and suggested doing a PhD study about Forcipomyia’s biology, phylogenetics, and their relationships with their hosts. I was politely refused, unfortunately. I still believe there is potential for a cool project involving Forcipomyia, maybe someone will pursue it in the future.

Little Transformers: Lamprosoma, the living Christmas ornament

Ah, the joy of transforming beetles. The first Little Transformer that opened this series of posts was a beetle – a Ceratocanthinae pill scarab that transforms into a perfect sphere and drops off to escape predators. It is an impressive evolutionary achievement that merges a successful body design and anti-predator behavior. I should mention though that many beetle species from other families use this strategy to avoid predation, some more successfully than others. One such example is a genus of small beetles from the leaf beetle family (Chrysomelidae): Lamprosoma.

Shiny leaf beetle (Lamprosoma sp.) from the Ecuadorian Amazon

Shiny leaf beetle (Lamprosoma sp.) from the Ecuadorian Amazon

When I first encountered a Lamprosoma beetle I thought it was a piece of plastic that someone discarded in the rainforest. There is something almost artificial about their appearance, shiny metallic colors combined with a compact shape. Not all species are colorful, by the way. The genus contains about 130 species, all with a neotropical distribution, some of which are completely black in color. With a body length of less than 1cm they are easy to miss in the dense vegetation of the tropical forest. Nevertheless, over the years I have encountered them more and more frequently. Unfortunately for me, identifying these beetles to the species level requires an expertise that I do not have, because there are many similar-looking species, and possibly also new species that have not been described yet.

Shiny leaf beetle (Lamprosoma sp.) from Honduras

Shiny leaf beetle (Lamprosoma sp.) from Honduras

The beetles are dome-shaped, and have very short legs. I think “cute” is the best way to describe them. As mentioned above, Lamprosoma can transform into a ball when threatened. In contrast to Ceratocanthinae beetles that have dedicated grooves to hold the legs and head in place, members of genus Lamprosoma have no such features. The beetle tucks in its head and holds its legs tightly close to its body, making it a neat impenetrable package.

Shiny leaf beetle (Lamprosoma sp.), a ventral view showing how neatly they press their legs against the body when forming the ball

Shiny leaf beetle (Lamprosoma sp.), a ventral view showing how neatly they press their legs against the body when forming the ball

Shiny leaf beetle (Lamprosoma sp.) in ball-mode. Mimicking a Christmas ornament.

Shiny leaf beetle (Lamprosoma sp.) in ball-mode. Mimicking a Christmas ornament.

In species with shiny metallic colors it is hard not to see the resemblance to the glass balls used as Christmas ornaments (maybe an idea for a future product?). Once the danger is out of sight, the beetle loosens its legs and walks away.

Shiny leaf beetle (Lamprosoma sp.) transformation sequence from ball-mode to beetle-mode. How can you not fall in love with those stubby feet?

Shiny leaf beetle (Lamprosoma sp.) transformation sequence from ball-mode to beetle-mode. How can you not fall in love with those stubby feet?

Lamprosoma are phytophagous beetles, meaning that they feed on plants. Both adults and larvae feed on leaves, and can be potential pests due to damage they can cause to foliage. The species shown here seem to be associated with cacao trees, and were found under leaves during the day. While the adults are very showy, the larvae are cryptic to avoid predators: they construct a case from frass and wood debris, and carry it around throughout their lifetime. The case is often shaped like a bent thorn, and blends perfectly with the branches the larvae live on. When threatened the larva retreat into the case and hold it firmly against the branch, preventing predators (such as ants and wasps) from accessing inside.

Another example of Lamprosoma sp. in ball-mode

Another example of Lamprosoma sp. in ball-mode

Shiny leaf beetle (Lamprosoma sp.). Full beetle-mode!

Shiny leaf beetle (Lamprosoma sp.). Full beetle-mode!

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!