My bucket list got shorter

Venezuela is a beautiful country, with everything from deserts to rainforests, snowy mountains to seasonally flooded savannas. I’ve been fortunate to have traveled to many of the different environments along the northern coast, from the arid Paraguaná peninsula, where I saw the world’s largest grasshoppers, to the incredibly biodiverse Paria peninsula, where I swam at night in a bioluminescent beach and released sea turtle hatchlings. However, I hadn’t visited the central part of the country, the Llanos, a vast, flat savanna teeming with wildlife. This changed this past weekend when I was asked to accompany the Ecology I course to Hato Masaguaral, so I could show undergrad students insect collecting techniques and show them how field work was done and just how different it was from lab work (many of them were interested in cell/mol bio, and due to a series of unfortunate events this was their first ever field trip).

A few hours after leaving the temperate climate of the mountains around Caracas we arrived at Los Llanos biological Station, where we made a brief stop. A few minutes after walking around the station and seeing an american kestrel nesting inside a termite mound, the course’s TA called me over so I could take a pic. She was pointing up at a tree stump with a smile on her face, saying “Look, it’s so cool!”. I looked up and there it was, a common potoo!

Tree stumps with feathers are common

Tree stumps with feathers are common

After a short drive, we arrived at Hato Masaguaral, we got settled in the houses for researchers. They were teeming with tree frogs and other critters, like this gravid female mantis that was on our doorstep

Stagmatoptera sp.

Stagmatoptera sp.

After dinner we were getting ready to go to the field very early the next day, but as I was taking a shower I heard one of the students, out of breath, tell the teacher that there was a snake in the bathroom. I quickly dried off, got my camera and saw it, a little colubrid that feeds mainly on small frogs. It was in the bathroom’s water tank, so we carefully took it outside for a quick picture before it slithered off.

Leptodeira annulata

Leptodeira annulata

We were up quite early the next morning, setting up the mist nets to capture and measure birds. It was a great sight, seeing everyone chirping with excitement (although many were half asleep) under a starry sky. It was a perfect photo opportunity.

Field work starts early and covered by stars

Field work starts early and covered by stars

After setting up the mist nets, we walked for a few minutes while the sun rose. In the meantime, one of the TAs (an expert in tracking mammals) showed the students how to recognize paw prints in the mud.

A typical sunrise in los llanos

A typical sunrise in los llanos

Around 8 am we headed back to the mist nets to see if we had collected anything. Sure enough, there were two troupials (our national bird) and two lineated woodpeckers. Our troupials are colorful birds, and they have quite a temper!

Icterus icterus

Icterus icterus

After that, the actual field work began. Under the scorching sun we walked towards the field site where the students would collect soil samples. I was ecstatic; amazing birds left and right, meter long snakes, crocodiles and lizards. Despite it being extremely hot and dry, there was plenty of wildlife. A few minutes later, I heard hoarse hissing sounds, as if something was exhaling loudly, and I was overcome with excitement, for I had been waiting ten years for this. They were hoatzins, shaggy, prehistoric-looking birds that are basically punk dinosaurs. They have long feathers that project upwards and backwards, like crests (which gives them their generic name, Opisthocomus).

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Opisthocomus hoazin

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We continued our walk torwards the field site, which to the students seemed like ten Km due to the scorching heat (we’re talking 42-44 C, with barely any wind and no clouds). Savanna hawks flew above us, while smaller birds rushed for cover when they heard us approaching.

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Buteogallus meridionalis

After a grueling mid-day field work session (and a slight scare, due to a student almost passing out from the heat), we headed back to camp. As we scouted for a place to set up the camera trap, one of the students squealed with delight as she pointed towards the trees. It was a small group of capuchin monkeys (Cebus olivaceus)! The alpha male wasn’t too thrilled to see me close by with my camera, and he rattled the branches as he grunted and screamed at me.

This is not a happy face

This is not a happy face

When we finally got back to camp, we were treated to a tour of the crocodile nursery. There they breed the critically endangered Orinoco crocodiles and release them in specific areas once they reach a certain length.

Chillin' in the nursery

Crocodylus intermedius

The following day I had only one other item to cross off my bucket list: See a burrowing owl. So a fellow colleague and ornithologist asked me to go with her first to a nearby pond to check out the aquatic birds, and after that we would look for burrowing owls. We saw plenty of birds on our way:

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Aplomado falcon, Falco femoralis

I hadn’t seen a large group of aquatic birds before, and seeing all of them fly at once is something amazing. It’s a living cloud, basically. We quickly counted the two species of whistling ducks (Dendrocygna autumnalis and D. viduata) and the black-necked stilts (Himantopus mexicanus) before heading over to the dunes to look for the burrowing owls.

Los Llanos went a little overboard with the Clone tool

Los Llanos went a little overboard with the Clone tool

Then, to finish an amazing trip, I saw them. After almost two decades of only seeing them in calendars and books, I saw them in real life. These little owls have a perpetual stare, and they make their nests underground.

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Athene cunicularia

All in all, despite the excessive heat and extremely dry environment, it was a fantastic trip, and I can’t wait to go again. I crossed several items off my bucket list: hoatzins, burrowing owls, deer, crocs, several eagles/haws/kestrels/falcons, and the Llanos themselves. Next time I will collect insects so I can leave an insect box at the camp’s museum. More pics will come in the future!

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The thing in the pits

You leave your home in the morning, as you do every day. On your way to work, you walk past a deep, conical pit, dug in fine sand, with smooth edges that lead to a small cavity at the bottom. As you continue walking, you notice more of these pits; they vary in size, but they are all the same shape.

The pits

Soon, you get too close to the edge of one of the pits, and a flurry of rocks blast from the bottom of the pit and hit your legs; before you know it, you’re tumbling down the sides of the pit, and if you try to slow yourself down and scale the smooth surface back to the top, you’re hit with another wave of rocks thrown at you from the center of the pit. Finally, you reach the bottom, where you can only see them when it’s too late: Two massive jaws, each with several sharp, pointed teeth, grab your sides and a creature you can’t see starts eating you while you’re still alive.

While this may seem like the plot for a SyFy original movie, this is a common occurrence in the insect world. The unfortunate creature that met its demise at the bottom of the pit is an ant, and the undescribed monster with the massive jaws is an antlion larva.

The thing in the pits

Antlions belong to the family Myrmeleontidae in the order Neuroptera, and its closest relatives, the lacewings and owlflies (Chrysopidae and Ascalaphidae, respectively) also have predatory larvae. However, they are active hunters, unlike antlion larvae; these dig conical pits in fine sand and wait for ants or other small arthropods to walk close to the edge, and when one does, they fling grains of sand at them until they tumble down the pit and into their massive jaws.

Now, as you can see in the above pic, they are basically huge abdomens with massive scissor-jaws. So how can they possibly hide? Easy: they have fine hairs all over their body that trap dust and sand, and then they bury themselves deep until only part of the jaws are visible at the bottom of the pit. Once buried, they wait motionless for an unsuspecting prey to walk by.

Of course, they’re very easy to see once they’re on a white surface and (somewhat) clean:

But place them on soil, and they immediately cover themselves with it and are notoriously hard to spot unless they move:

I enjoy seeing these larvae because they are a) Visually awesome and b) They show spectacular behavior when they’re capturing prey. I definitely wouldn’t want to be a small arthropod near one of these pits, particularly when I know what’s at the bottom!

Limping around

The thought of us humans losing a limb is catastrophic, but some insects can shrug it off, or at least to some extent.

Stick insects (order Phasmatodea) are able to regenerate limbs without apparent tradeoffs [1], but insects such as mantids aren’t so lucky. Limb regeneration can ocurr if it is severed during early instars, but the limb will have four tarsi instead of five and will usually be shorter [2].

I was able to witness this during my latest field trip with a female Stagmatoptera. Notice that the left hind leg is shorter:

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The atrophied leg didn’t appear to hinder the insect’s movement, although I did notice it moving slower than males of the same species. This may be due to the males being thinner and not as heavy as the female, though.

1.- Maginnis, T. & Redmond, C., 2009. Leg Regeneration Trade-Offs in the Twostriped Walkingstick (Phasmatodea: Pseudophasmatidae). Annals of the Entomological Society of America: Vol. 102, Issue 6, pg(s) 1099-1104 doi: 10.1603/008.102.0618
2.- Ramsay, G.W. 1990. Mantodea (Insecta), with a review of aspects of morphology and biology. Fauna of New Zealand, No 19

Wasp-mimicking katydids

Imagine yourself in a tropical jungle. You see a medium sized insect, about 3.5 cm long, land on a light trap. Its body is elongated, metallic black with a bluish hue, bright orange wings and long orange and black antennae. It walks around moving its antennae really fast. What could it be?

– “Dan, It’s a tarantula hawk, a wasp in the family Pompilidae, duh!

Not so fast! In the insect world, things aren’t always what they seem, and this is a fine example:

Aganacris

This jaw-dropping katydid (Tettigoniidae; Phaneropterinae) belongs to the genus Aganacris, and it mimics a pompilid wasp (Pepsis are relatively common here and have very similar colors) with remarkable accuracy. Aposematic wasp mimics are common in the insect world; you can see many examples in flies (Syrphidae), moths (Sesiidae) and beetles (Cerambycidae), but seeing it in a katydid was a first. As it turns out, wasp mimicry in tettigonids is pretty rare; Nickle and Castner studied the strategies against diurnal predators used by this group in Perú, and most of the groups were leaf/bark/twig/lichen mimics; only two genera, Aganacris and Scaphura, were found to be wasp mimics. [1]

This is another first for me (I mentioned pentatomids making insect smoothies earlier), and I couldn’t be happier. Even though I’ve been to this particular biological station quite a few times, every time I go there I see something new and simply astonishing.

1.- David A. Nickle and James L. Castner, 1995. Strategies Utilized by Katydids (Orthoptera: Tettigoniidae) against Diurnal Predators in Rainforests of Northeastern Peru. Journal of Orthoptera Research, No. 4, pp. 75-88. http://www.jstor.org/stable/3503461

The impaler

There are always outsiders in entomology, groups that don’t follow the norm. We’re taught, for example, that stink bugs are herbivorous (and often pests), that some feed on nitrogen-rich reproductive parts of plants while others feed on somatic tissue. So when you see a pentatomid on a light trap, you might think “How cute, look at this little bug! I wonder if there’s a plant around here it might feed on“. Then along comes the nasty little critter and impales a moth like it’s a scene from 300:

The poor moth never stood a chance

The poor moth never stood a chance

One might think it’s a fluke and not a regular occurrence, but then the next night you see the same thing, only this time it’s a poor ant that gets eaten:

Ant on a stick

As it turns out, there’s an entire subfamily of stink bugs (Pentatomidae: Asopinae) that is predatory, and it has been used as a pest control agent [1]. While its entomophagous habits are pretty well documented, I had never actually seen one. Finding out that some stink bugs make insect smoothies was one of the highlights of my recent jungle trip; I’ll leave the other ones for future blog posts!

1.- Robert G. Foottit and Peter H. Adler, 2009. Insect Biodiversity: Science and Society. Blackwell Publishing Ltd. ISBN: 978-1-405-15142-9 Chapter 10: Biodiversity of Heteroptera – Thomas J. Henry

Pre-NMW 2013

We are currently in the middle of National Moth Week, and I am organizing a mothing event in a biological station (trying to, at least; I was supposed to leave yesterday but I had car trouble). I’ve been there several times and the moth diversity is astonishing: big/small, colorful/inconspicuous, with pointy or rounded wings, they’re all there.  I’d like to show you a few specimens that you can find there; I focused on macrolepidopterans when I took pictures, because they were less skittish than microleps.

A classic Automeris

A classic Automeris

Who said moths had dull colors?

Who said moths had dull colors?

Wasp mimics are a common sight at the light trap

Wasp mimics are a common sight at the light trap

Patterns and markings abound

Patterns and markings abound

Like I said, plenty of wasp mimics!

Like I said, plenty of wasp mimics!

And finally, one of my personal favorites, the Dog-faced moth:

Looks like a dachshund or a basset hound

Looks like a dachshund or a basset hound

This is barely a small fraction of the astonishing moth diversity you can find there (not to mention other arthropods), and I hope to be able to photograph and collect a lot more that I have in past visits. If everything goes well and I manage to go, I’ll write a post-NMW 2013 post sometime next week after processing data and images.

 

 

Peculiar hitchhikers

Phoresis has been well studied interaction in biology, and it has been reported in both vertebrates and invertebrates. An example of vertebrate phoresis is the remora (Perciformes: Echeneidae), whose first dorsal fin is modified into an oval sucker that allows it to attach itself to larger marine animals, and one example I’ve seen often in invertebrates is pseudoscorpions on beetles, particularly longhorns (Cerambycidae). But I recently learned that phoresis in invertebrates is a world about which I know nothing.

We collected some beetles in the Andes a few weeks ago. Nothing too eye-catching, just some scarabaeids that landed on the light trap. We collected a few and didn’t think much about them after that, so they stayed in a jar at the lab. I reviewed the contents of the jar earlier this week and saw something interesting: about 30-40 mites were floating around in the alcohol, and two beetles had this:

Beetle is roughly 3 cm long

Beetle is roughly 3 cm long

I didn’t recognize these structures, at least not on a beetle we captured alive. We had seen molds on dead beetles that had a similar overall shape, but there was one catch: molds don’t have legs!

Definitely not a mold!

Definitely not a mold!

I did what I usually do when I’m stumped and have no immediate access to my books/computer: I turned to Twitter for help. Sure enough, I soon received replies regarding these animals. Christopher Taylor (@CatOfOrgidentified them as phoretic Uropodina mite deutonymphs, and gave some insight as to what that stalk-like structure was. After that, Wayne Knee (@whknee) added that these mites use liquid glue, and form the pedicel by moving ahead, and that the mite later detaches, leaving the pedicel behind.

Sure enough, I found that different mites have different types of pedicels: they can be long, short, irregularly shaped, straight or helically coiled, and they can be homogenous or formed by packed bundles of fibers [1]. These are to assure successful phoresis on their hosts. I also found that host selection can be either very specific (one single species of centipede [2]) or non-specific (25 different species of beetles from several families [3]), but in both studies there appears to be a tendency for selecting specific body parts from which to attach the pedicel.

For the second time this week, I was stumped by arthropods (the first time was by some odd little things), which I really enjoy, for it means I’m always learning something new! And, again, it proves that Twitter can be an excellent tool for learning and sharing information.

1.- Bajerlein, D., et al., Morphological diversity of pedicels in phoretic deutonymphs of Uropodina mites (Acari: Mesostigmata), Arthropod Structure & Development (2013), http://dx.doi.org/10.1016/j.asd.2013.02.002

2.- Bloszyk, J., Klimczak, J. & Lesniewska, M., Phoretic relationships between Uropodina (Acari: Mesostigmata) and centipedes (Chilopoda) as an example of evolutionary adaptation of mites to temporary microhabitats, Eur. J. Entomol. 103: 699–707, 2006

3.- Bajerlein, D. & Bloszyk, J., Phoresy of Uropoda orbicularis (Acari: Mesostigmata) by beetles (Coleoptera) associated with cattle dung in Poland, Eur. J. Entomol. 101: 185-188, 2004