Archive For: Colombia

Spiderception: jumping spider-mimicking jumping spider (Parnaenus sp.)

After a long hiatus of nearly 5 months, I thought it is about time I shake the dust off this blog and return to posting. This month we are celebrating Arachtober, highlighting spiders and other arachnids to promote appreciation and understanding that these animals are crucial to the normal function of ecosystems, and that they have their rightful place on this planet. Today is also International Jumping Spider Day, so it is a great opportunity to discuss something interesting that some of these cuties share.

Last February I was fortunate to spend a week in Colombia for a photography assignment. In one of our day hikes I checked a cluster of hanging vine flowers to see if there are interesting insects hiding inside. I did not find any insects except for ants, but as I was peeking inside the inflorescence I saw a row of shiny eyes staring back at me. I thought to myself – Oh, cool. A jumping spider. And indeed it was a salticid spider, however what I thought were eyes was nothing but a deception. In fact the spider’s head was facing away from me, and it was busy munching on a small moth.

Male Parnaenus jumping spider playing peek-a-boo. These spiders become even more interesting when viewed from behind.

Male Parnaenus jumping spider playing peek-a-boo. These spiders become even more interesting when viewed from behind.

Lateral view of a female Parnaenus jumping spider from Colombia. The color pattern on the abdomen resembles jumping spider eyes.

Lateral view of a female Parnaenus jumping spider from Colombia. The color pattern on the abdomen resembles jumping spider eyes.

Female jumping spider (Parnaenus sp.). They are much cuter when looking straight at you!

Female jumping spider (Parnaenus sp.). They are much cuter when looking straight at you!

Even though there are almost no identification keys for jumping spiders from the neotropics, I am confident that the spider I found was a female Parnaenus. For the most part these are plain looking jumping spiders, but their abdomen is usually covered with blue and green iridescent scales. On both side of the abdomen they have a row of spots that look exactly like jumping spider eyes. In fact, due to the contrast with the colorful abdomen, those spots are even more noticeable than the spider’s actual eyes. And it’s not just the female Parnaenus that possess these spots; the smaller and more colorful males have them too.

Male Parnaenus jumping spider. Huge head with stunning iridescent colors.

Male Parnaenus jumping spider. Huge head with stunning iridescent colors.

Dorsal view of a male jumping spider (Parnaenus sp.). From this angle you can see how easy it is to mistake the spots on the abdomen for eyes.

Dorsal view of a male jumping spider (Parnaenus sp.). From this angle you can see how easy it is to mistake the spots on the abdomen for eyes.

Jumping spiders are visual creatures. They rely on visual cues and their good eyesight to detect prey, competitive conspecifics, and potential mates. This is why many species of jumping spiders developed complex color patterns to assist in communication with other individuals. Other arthropods also take advantage of this and deploy mimicry to fool these spiders and avoid predation. One of the most common jumping spider mimicry is the presence of eyespots arranged in a row, to resemble the spiders’ large frontal eyes. I have already written about such cases on this blog, usually demonstrated by moths, but other insects as well (see here and here for examples). We have also seen jumping spiders using mimicry to resemble insects. What we have not seen yet though, is jumping spiders mimicking jumping spiders. Is this even possible? Well, yes and no.
Yes, because there are definitely jumping spider species that display a clear salticid eyespot pattern away from their head where their actual eyes are – like the Parnaenus species presented in this post. And no, because we have no evidence that they are truly mimicking other jumping spiders.

Male Parnaenus jumping spider. So pretty.

Male Parnaenus jumping spider. So pretty.

A closer look at the abdomen of a male Parnaenus jumping spider. False eyes between green and blue scales.

A closer look at the abdomen of a male Parnaenus jumping spider. False eyes between green and blue scales.

This spiderception is quite confusing. At first it looks like the salticids deploy a “false head” anti-predator tactic in order to fool their predators and direct their attacks away from the animal’s real head. But in the case of these spiders the eyespots pattern is located on the abdomen, the most vulnerable part of the spider’s body. On the other hand, if they really use this pattern to communicate with other jumping spiders, we would expect to see a specific behavior associated with it, like waving the abdomen or displaying it in front of another individual. And to the best of my knowledge there are no such observations in existence.

Male Parnaenus jumping spider from Colombia

Male Parnaenus jumping spider from Colombia

Parnaenus is not the only jumping spider genus that has eyespots on its abdomen, by the way. Other dendryphantine jumping spiders possess this character, to varying degrees. Those include the beautiful Paraphiddipus and Metaphiddipus jumpers and the scorpion spiders of genus Lurio. The latter is a very unusual jumper – the forelegs are disproportionally robust and long compared to the others, both in males and females.

Female scorpion spider (Lurio sp.) guarding eggs. Taironaka, Colombia

Female scorpion spider (Lurio sp.) guarding eggs. Taironaka, Colombia

Scorpion spiders (Lurio sp.) have a color pattern on their abdomen that is very similar to that of Parnaenus spiders.

Scorpion spiders (Lurio sp.) have a color pattern on their abdomen that is very similar to that of Parnaenus spiders.

Female scorpion spider (Lurio sp.) guarding eggs. Even without the pretty colors these spiders are very unique, with their long thick forelegs.

Female scorpion spider (Lurio sp.) guarding eggs. Even without the pretty colors these spiders are very unique, with their long thick forelegs.

The salticid eyespot pattern is quite common in nature, and it seems that possessing it positively affects the bearer’s chances of survival. Even jumping spiders themselves have it on their body. But do they really use it for active communication? Or is it more a passive way for them to say ‘I am a jumping spider inside and out’? Those are questions that are still left unanswered, at least until someone follows and documents their behavior.

Lyssomanes – the spider from the upside down

Out of all the different microhabitats plants provide for organisms, the living leaf is arguably the most underrated one. On the surface it seems that it pales in comparison to the rich leaf litter of the forest understory, or to the complex bark of trees that provide hiding and hunting spots for many animals. However, although the green leaf may look innocent, it in fact holds many stories of deception and survival. The upper surface of the leaf offers exposure to sunlight and water, as well as additional nutrients coming from above. It can serve as a solid base for the growth of ferns, mosses, lichens, and fungi. It can also be folded and glued to create a nest or shelter for an animal or its eggs. Not to mention that in many plants the entire leaf comprises of edible material available for herbivores. But there is another plane of existence, a much darker reality. It is located in a parallel dimension – an inverted copy of the leaf upper surface. This is the upside down world of the leaf underside. Many organisms live here; some only take shelter during the day and resume activity on the upside world at night, others prefer to feed under the leaf to avoid predators. But one of the most fascinating examples is a group of predators that learned to utilize the leafy upside down for ambushing prey. I have already written about two of those, and today I would like to present another member of this guild: Lyssomanes, the green jumping spider.

Green jumping spider (Lyssomanes sp.). The spider's pale color helps it to blend in with the leaf it is sitting on.

Green jumping spider (Lyssomanes sp.). The spider’s pale color helps it to blend in with the leaf it is sitting on.

At first glance Lyssomanes doesn’t look like a typical jumping spider. It has very long and slender legs, and prefers to move by running and using short leaps as opposed to the jumps that characterize most members of the salticid spider family. In addition, the spider is almost completely hairless, sporting a pale body color, usually (but not always) green, and occasionally semi-translucent. Unlike other jumping spiders, the only scales covering the body are clustered as a crown on its head. Those can be white, yellow, orange, red, or any combination of these colors, depending on the species and developmental stage. Sometimes dark banding is present on the legs, usually in adult males.

Green jumping spiders (Lyssomanes sp.) often have a glossy, semi-translucent body, with a crown of colorful scales on their head.

Green jumping spiders (Lyssomanes sp.) often have a glossy, semi-translucent body, with a crown of colorful scales on their head.

The genus Lyssomanes contains around 90 species, all distributed in the Americas. Many species have similar external appearance. The type species from which the genus was described is named Lyssomanes viridis (from Latin – green jumping spider), but if I want to be completely honest, almost every species I encounter looks ‘viridis’ to me. They are just so green!

Not all Lyssomanes jumping spiders are green. Some are lemon yellow like this species from Belize.

Not all Lyssomanes jumping spiders are green. Some are lemon yellow like this species from Belize.

One of the most noticeable features of Lyssomanes jumping spiders is their enormous anterior median eyes. Because of the spider’s pale color, it is also very easy to observe the internal retinal movements as the spider angles and focuses its field of view. The eyes may appear black at times, or pale green, crossed, or alternating (here’s a fantastic video showing this, and watch what happens when an ant passes by!).

Green jumping spider (Lyssomanes sp.) staring straight back with its huge eyes. If you don't think it is cute you might want to check your pulse.

Green jumping spider (Lyssomanes sp.) staring straight back with its huge eyes. If you don’t think it is cute you might want to check your pulse.

Female Lyssomanes are very modest in their appearance. Males on the other hand, are impressive beasts with long pedipalps and elaborate chelicerae, often armed with thick setae and teeth. The latter are used in male fights for mates. Males also have extremely long legs, which they use for pushing an opponent and waving to females as a part of the courtship process.

Male Lyssomanes spiders have long legs and pedipalps for signalling conspecifics, and often sport impressive chelicerae for fighting other males.

Male Lyssomanes spiders have long legs and pedipalps for signalling conspecifics, and often sport impressive chelicerae for fighting other males.

Closeup on a male Lyssomanes spider. Notice the teeth on the long chelicera.

Closeup on a male Lyssomanes spider. Notice the teeth on the long chelicera.

Portrait of a male green jumping spider (Lyssomanes sp.) with his long chelicerae

Portrait of a male green jumping spider (Lyssomanes sp.) with his long chelicerae

Similarly to other predatory dwellers of the leafy upside down, Lyssomanes spiders deploy an ingenious hunting technique. The spider’s huge eyes are a good indication of its hunting method – it uses its excellent vision to locate prey. Lyssomanes jumping spiders are diurnal sit-and-wait predators of dipterans and other soft-bodied arthropods. They prefer to sit on leaves that are exposed to the sun, waiting in ambush for a visitor on the upper surface to cast a dark shadow. If the shadow is of the right size and shape the spider will shoot itself from the underside to the upper leaf surface and snatch the unsuspecting prey.

Male green jumping spider (Lyssomanes sp.) ambushing prey on the underside of a leaf backlit by the sun

Male green jumping spider (Lyssomanes sp.) ambushing prey on the underside of a leaf backlit by the sun

Occasionally, if sunlight is obstructed, the spider will explore the leaf and actively search for passing insects. It does not, however, stay loyal to one leaf. Once spotted, the spider usually does not take any chances and relocates to a nearby leaf.

Snap! When startled, the green jumping spider (Lyssomanes sp.) swiftly moves to the other side of the leaf.

Snap! When startled, the green jumping spider (Lyssomanes sp.) swiftly moves to the other side of the leaf.

Although jumping spiders rarely use silk for hunting, most of them build a small silky sleeping bag inside a crevice or a folded leaf for resting at night and molting. Lyssomanes is unique in that it does not construct such a shelter. Instead, it lines the underside of the leaf with a thin carpet of silk, and rests on it completely exposed.

Green jumping spider (Lyssomanes sp.) spinning silk on the underside of a leaf

Green jumping spider (Lyssomanes sp.) spinning silk on the underside of a leaf

Gravid females construct a similar web for their eggs. Passing insects often trample the sheet, which triggers a predation response from the spider.

Female green jumping spider (Lyssomanes sp.) protecting her eggs

Female green jumping spider (Lyssomanes sp.) protecting her eggs

Cannibalism is common in salticids. Here, a green jumping spider (Lyssomanes sp.) is preying on a smaller spider that happened to walk on its leaf.

Cannibalism is common in salticids. Here, a green jumping spider (Lyssomanes sp.) is preying on a smaller spider that happened to walk on its leaf.

Unfortunately, this habit of Lyssomanes to sit exposed also means that they are sitting ducks for other predators, usually other species of jumping spiders. Remember – it is a harsh world out there and it’s not easy being green!

The grass is not always greener on the other side of the fence - a green jumping spider (Lyssomanes sp.) has fallen prey to another jumping spider!

The grass is not always greener on the other side of the fence – a green jumping spider (Lyssomanes sp.) has fallen prey to another jumping spider!

 

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?