Archive For: Honduras

Little Transformers: Deinopis, the ogre-faced spider

Today’s Little Transformer is a little unusual. First off, it is a spider. This spider is so unique in its appearance and behavior that I am surprised it has not inspired any exaggerated depictions in popular culture. It spends most of its time hidden, posing as a harmless twig among the forest vegetation. It is so good at what it does, that unless it moves it would be very easily overlooked. However, when night falls this seemingly harmless twig transforms into a sophisticated killing machine. Meet Deinopis, the ogre-faced spider (also known as net-casting spider).

Net-casting spider (Deinopis sp.) from the Ecuadorian Amazon

Net-casting spider (Deinopis sp.) from the Ecuadorian Amazon

Net-casting spider (Deinopis spinosa) frontal view. Their eye arrangement is one of the weirdest of all spiders. Notice the lateral eyes are pointing down!

Net-casting spider (Deinopis spinosa) frontal view. Their eye arrangement is one of the weirdest of all spiders. Notice the lateral eyes are pointing down!

Ogre-faced spiders are found on every continent except Europe and Antarctica, but they occur mostly in warm regions of the southern hemisphere. Found primarily in Latin America, Africa, Madagascar, and Australia, these spiders all share the same appearance: brown color, elongated body with long forelegs, and an unmistakeable face. The small family Deinopidae contains only two genera: Deinopis, holding most of the species, and Menneus.

Net-casting spider (Deinopis spinosa) camouflaged as a twig or a dried leaf

Net-casting spider (Deinopis spinosa) camouflaged as a twig or a dried leaf

Interesting texture and patterns on the dorsal side of a net-casting spider (Deinopis spinosa). The legs are held tightly to form a typical 'X' shape at rest, making it look like the spider has only four legs.

Interesting texture and patterns on the dorsal side of a net-casting spider (Deinopis spinosa). The legs are held tightly to form a typical ‘X’ shape at rest, making it look like the spider has only four legs.

Deinopis are very unique among spiders for having superb vision, thanks to their huge median eyes.

Net-casting spider (Deinopis spinosa). Those eyes... You can now understand why they are called ogre-faced spiders.

Net-casting spider (Deinopis spinosa). Those eyes… You can now understand why they are called ogre-faced spiders.

A closer look at the median eyes of a net-casting spider (Deinopis spinosa). Staring straight into your wretched soul.

A closer look at the median eyes of a net-casting spider (Deinopis spinosa). Staring straight into your wretched soul.

The big eyes are what gave these spiders their common name, and they are so big that it is easy to miss the other six eyes on the spider’s head. I did my best trying to capture the stone-cold expression on a Deinopis spinosa face, but also check out Michael Doe’s amazing work with the Australian species D. subrufa. These median eyes are extremely sensitive to light, despite lacking any reflective tissue behind the lenses. Instead, a light sensitive membrane is formed inside the eyes every night, and then gets broken down at dawn. This allow the spiders to track subtle movements in complete darkness during their activity hours, something that is essential for their unique hunting strategy. While somewhat close to other weavers, ogre-faced spiders do not construct a fixed web to trap their prey. Instead they make a rather small hand-net, a handkerchief if you wish, that they use to catch insects passing nearby. The silk constructing the net is not sticky but extremely fuzzy and flexible, thanks to a special comb-like structure on the spider’s legs that stretches and frizzle the silk as it is coming out of the spider’s spinnerets.

Net made by a net-casting spider for catching prey

Net made by a net-casting spider for catching prey

A closer look at the net reveals the wooly silk used to make it. If you look carefully you will notice that it is coiled like a spring, allowing the silk to be stretched and expanded to completely cover the prey.

A closer look at the net reveals the wooly silk used to make it. If you look carefully you will notice that it is coiled like a spring, allowing the silk to be stretched and expanded to completely cover the prey.

The spider usually shapes the net as a square, and holds it loose over a branch or a leaf where an insect is likely to walk.

Net-casting spider (Deinopis sp.) from Colombia

Net-casting spider (Deinopis sp.) from Colombia

Once it spots a suitable prey, the spider quickly stretches the net and snatches the passing insect by hand. The net can be stretched and expanded up to five times its original size without being torn, thanks to the special attributes of the silk. It entangles anything it touches. The spider is extremely fast in its response that sometimes it succeeds in capturing passing insects in mid-flight, again – completely by hand. You have to appreciate the speed and accuracy that goes into this hunting technique.

Net-casting spider (Deinopis sp.) ready for an insect to pass on a nearby branch. These spiders usually place themselves right above a possible walkway for arthropods. Photographed in Ecuador

Net-casting spider (Deinopis sp.) ready for an insect to pass on a nearby branch. These spiders usually place themselves right above a possible walkway for arthropods. Photographed in Ecuador

Net-casting spider (Deinopis sp.) from Honduras

Net-casting spider (Deinopis sp.) from Honduras

It is relatively difficult to witness this behaviour in the field, mainly because by observing at night we add another component to the equation – light. In fact, in all my trips to Latin America I have encountered these spiders many times, but only once I was able to see the spider hunting… and totally missing the prey insect. So you can imagine my excitement when I realized I was going to work with one of the species, Deinopis spinosa, while it is on display at the Royal Ontario Museum’s “Spiders: Fear & Fascination” exhibition. For several weeks I tried to get a glimpse of it feeding but without success. One day I decided to toss a cricket close to it before leaving the exhibit area and within a spilt second the spider responded and caught it! I was in awe. I had to find a way to record it on video for people to see. I enlisted Daniel Kwan, one of my colleagues at the museum who has more videography experience, and we set out to produce a short movie. It took us many attempts to get decent footage of the hunting behaviour. Many times the prey crickets tried to hide, and occasionally the spider would respond to them but miss. Even though feeding the spider in an artificial environment means we had more control, it was really difficult. It makes me wonder how long the spider must wait in the wild until it is able to catch a meal.

Also worth mentioning is genus Menneus from the same family. These spiders are much smaller than Deinopis and they lack the large median eyes, therefore they are not true ogre-faced spiders. However, they spin a catch net and use the same strategy for hunting prey. The genus contains only a handful of species, distributed mainly in Australia, but with some representation in Africa. Some of the species are quite beautifully patterned compared to the plain-looking Deinopis, and there are even green-colored species! You can find some photos of Menneus spiders at the bottom of this page.

Something I was thinking about while writing this post – why do I never encounter small deinopids in the field? It would be really cute if they had miniature nets for catching even smaller insects. Even when I look for information online and in the literature, it only concerns medium-sized juveniles and adults. Could it be that the small ogre-faced spiders actually have a different hunting strategy than that of larger individuals?

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!

Little Transformers: Pycnopalpa bicordata

It comes as no surprise that the first two “Little Transformers” presented on this blog were beetles. Many beetles are capable of folding, taking the shape of different structures, whether it is for camouflage or as a means of defense against predators. I will surely present more examples of transforming beetles in future posts. However, there are other insects out there that have the same transformation ability. I had the fortune of meeting one of those insects while staying at a jungle lodge in Honduras. My visit was in the middle of a dry spell and insects were surprisingly scarce. Many of the hikes I took in the rainforest were unfruitful. In my frustration I decided to check the screen windows outside a nearby facility because sometimes insects decide to rest on the mesh. I did spot a few nice finds, and then, I saw this.

"It's a bird! It's a plane!"

“It’s a bird! It’s a plane!”

My first thought was ‘that is one weird-looking moth’.
Let me explain.
My entomologist mind is on a constant search to find familiar patterns in objects that I see, because in the tropics deception is lurking everywhere. What I saw first was the animal’s shape and took it immediately for a winged insect. Then the coloration and the pose reminded me of some Erebidae moths (for example, genus Eutelia).
It took me a couple of short attempts to refocus my eyes on what is important before I could see that this is not a moth at all.

Now that the insect is off the net, we can take a better look. Dorsal view.

Now that the insect is off the net, we can take a better look. Dorsal view.

Another view of this amazing insect

Another view of this amazing insect

This is in fact a katydid nymph, Pycnopalpa bicordata, and it is so good at what it does that I was not able to locate it much later as it was sitting among fallen leaves in the vial I put it into. Whenever it is inactive it will assume this position, blending in with tree bark or leaf litter in the forest understory. Whether it resembles a moth or not is a matter of personal opinion at this point, because unless there is concrete evidence for an unpalatable moth model that this katydid is mimicking, the body posture this katydid takes can be within a different context altogether, such as a shredded fallen leaf or something similar.

Viewing from the side reveals that this is a leaf-mimicking katydid nymph (Pycnopalpa bicordata) at rest

Viewing from the side reveals that this is a leaf-mimicking katydid nymph (Pycnopalpa bicordata) at rest

The nymph (Pycnopalpa bicordata) in full katydid-mode

The nymph (Pycnopalpa bicordata) in full katydid-mode

Leaf-mimicking katydid nymph (Pycnopalpa bicordata). Clever girl!

Leaf-mimicking katydid nymph (Pycnopalpa bicordata). Clever girl!

As mentioned above, this is a nymph. A juvenile female to be more accurate, as can be seen by her sickle-shaped ovipositor. So what does the adult katydid look like? I was expecting some mind-blowing leaf appearance; maybe with flattened fins and spines on the legs, to mimic a dried leaf chewed up to its veins. You can safely say that I was exaggerating, and in the end when the nymph molted to its adult stage I was rather disappointed.

The adult Pycnopalpa bicordata is a delicate leaf-mimicking katydid. This one is a male.

The adult Pycnopalpa bicordata is a delicate leaf-mimicking katydid. This one is a male.

The adult Pycnopalpa bicordata is a very delicate insect with no major body modifications for mimicry or camouflage. Yes, it still looks very much like a leaf – having vivid green wings with transparent cells surrounded with brown margins, representing consumed parts or sunburn damage to leaf tissue. But the adult stage pales in comparison to the ingenious structural design of the nymph. Still, it is very nice to find Little Transformers outside the realm of Coleoptera. Moreover, among the orthopterans, I can think of at least one additional species of katydid and several grasshoppers that fall under my definition for Little Transformers. Hopefully we will get to learn about them in future posts.