February 27, 2015

Deception in the Jungle: the Ant-mimicking Spider Aphantochilus rogersi

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Things aren't always as they seem in the jungle. As the sun was setting and we were heading back to the Tambopata Research Center, Chris Johns made a very cool spot. At first it appeared as if two ants were stuck together on a branch...but upon closer inspection we realized that we were dealing with an ant-mimicking spider feasting on its ant prey.


The mimic in this case is a neotropical crab spider Aphantochilus rogersi (right). It is an incredible mimic of Cephalotes ants (its prey on the left).  Chris and I had to count the legs to be convinced it was really a spider. This type of ant-mimicry is known as myrmecomorphy, as these spiders have evolved morphological and behavioral characteristics to resemble ants.

Myself and the December team photographing some arthropods 'Meet Your Neighbors' style.

But why did this ant-mimicry trait evolve in the spider? Well let's break it down:

  • Ants are often equipped with chemical defenses and have lots of sisters to defend one another. This makes them risky prey items for a predator.
  • Spiders, on the other hand, are usually solo and make a juicy meal for a predator, like a bird.
  • So, if spiders become selected over evolutionary time to appear more like ants, it could trick visual predators into avoiding them. This is known as Batesian mimicry: when a harmless species has evolved to imitate the warning signals of a harmful species.


However, as pointed out in the comment thread in Alex Wild's post on these spiders, Cephalotes ants have pretty good vision. So if the spider was less convincing in its mimicry, the Cephalotes ants might be able to avoid the predator before it gets too close. It could be that this spider evolved to look like Cephalotes ants for both reasons: to trick the ants, and to trick visual predators.



So the next time you find yourself walking around nature, just remember: things aren't always as they seem.

-Aaron

Citation: Castanho LM, Oliveira PS (1997) Biology and behaviour of the neotropical ant-mimicking spider Aphantochilus rogersi (Araneae: Aphantochilidae): nesting, maternal care and ontogeny of ant-hunting techniques. Journal of Zoology 242: 643-650.


You can follow Aaron on Twitter @AaronPomerantz


February 23, 2015

Changing the World with a 50-Cent Paper Microscope

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Anyone who has spent time in a lab has likely hunched over a microscope at some point. They are standard instruments for visualizing and investigating small objects. The problem is that microscopes are relatively large and expensive, which can be a barrier to people with an interest in science or microscopy but who can't afford this bulky piece of equipment. This can also make work outside of the lab challenging, especially if you find yourself trying to explore something tiny out in the middle of a jungle or in an under-developed country.

This is where the "Foldscope" comes in, a device developed by the Prakash Lab at Stanford University. This origami-based optical microscope weighs in at a whopping 8.8 grams (less than two nickels), is small enough to fit in a pocket, and costs less than one dollar.

foldscope start

The Foldscope initially arrives as a sheet of paper with two primary fold-out parts. Just pop these out, follow the instructions (it comes with an instruction manual as well as online video step-by-step instructions) and the set up is complete in less than ten minutes.

folscope done 

The final product is a 70 x 20 x 2 mm³ microscope platform. The Foldscope kit also comes with a low-magnification lens, a high-magnification lens, magnetic strips (allows for connection to a cell phone), and a light module. Slides are inserted into the platform and samples are viewed through a micro-lens while you can pan and focus with your thumbs.

This device could provide important opportunities for examining specimens in the field as well as screening and diagnostics for disease-causing agents. For instance, the Foldscope can be used to detect:
  • Plasmodium falciparum (parasitic protozoan that causes malaria)
  • Leishmania donovani (parasitic protozoan that causes leishmaniasis)
  • Eschleria coli (bacterium that can cause painful abdominal cramping and severe, sometimes bloody, diarrhea)
  • Trypanosoma cruzi (parasitic protozoan that causes Chagas disease)
  • Human sickle cell
  • And much more
By removing cost barriers, the researchers hope that the Foldscope will provide new opportunities for a broad user base in both science education and field work for science and medicine.

size comparison banana 
 Size comparison of a stereo microscope (top) the Foldscope (bottom left) and banana for scale (bottom right)

foldscope images 4 
The Foldscope can also be connected to a standard smartphone for taking images or video. Here are a few images taken using the low-mag lens (140X magnification) on an Android phone: cells of a leaf (top left), sugar crystals (top right), a phytoseiid mite from my garden (bottom left), and celery stalk (bottom right). I think my preparation of the slides could be improved to produce better images, but all-in-all I'm still amazed that these were taken using a paper-based 50-cent microscope.

Another important point that the authors bring up is that many children have never used a microscope, even in developed countries like the United States. A universal program providing a "microscope for every child" could help to foster an interest in science at an early age. They hope to make microscopes approachable, accessible, and inspire children to examine biodiversity on our planet as amateur microscopists and to make discoveries of their own.

Overall, I'm pretty excited about this device. It's cheap, it's simple, and it works - but this invention required an amazing amount of research and engineering by the Stanford group. I'll be bringing the Foldscope with me on my next trip to the Peruvian Amazon and hope to investigate some interesting small organisms while there. Stay tuned!

-Aaron


Citation: Cybulski JS, Clements J, Prakash M (2014) Foldscope: Origami-Based Paper Microscope. PLoS ONE 9(6): e98781. doi:10.1371/journal.pone.0098781


You can follow Aaron for more updates on Twitter @AaronPomerantz and the Stanford Researchers @PrakashLab 

February 12, 2015

Gateway into the Amazon by Nicole Lizares

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Nicole Lizares works for conservation organizations in the Philippines and recently joined us for an expedition to the Tambopata Research Center. Below is an article published by Nicole in the February/March 2015 issue of 'Explore Philippines'. Enjoy!



Text version:

'Stumbled' is perhaps not the most impressive word to describe how I managed to find myself in the middle of the Amazon rainforest, given that I was a grad student who had supposedly done her research well and had prepared meticulously for this trip, but it is the most appropriate.

After more than 29 hours hopping on and off airplanes, riding in cabs, a bus, and finally, on a boat upstream for what felt like an eternity (it was really just around four hours), I found myself dusty, sweaty, and stumbling along a trail in the middle of the Tambopata National Reserve, one of the largest protected areas (covering more than 271,000 hectares of land) on the Peruvian side of the Amazon. Our final destination: The Tambopata Research Center, a.k.a TRC, an eco-lodge owned and operated by Rainforest Expeditions. I thanked the heavens that I was in their good hands.

Reputed to be one of the most remote eco-lodges in South America and the only one to be situated inside a national reserve, the TRC is in a very unique position. One of the world's largest clay licks (mounds of mud and salt deposits where thousands of birds flock every morning to get their dose of the mineral) is a mere 500 meters from the lodge. The TRC's remote location also means that the forest ecosystems around it remain pristine and largely untouched, offering researchers and scientists a rare opportunity to study wildlife in their most undisturbed state.

In fact, the lodge's name harkens back to a time when it was purely that: a research center, housing scientists who were studying the macaw population and working to protect the wild birds from illegal hunters.

"That was back in 1989," shares our local forest guide, Frank Pichardo. "Eduardo Nycander, he was a wildlife photographer who started The Macaw Project in this area to gather information about the macaws that could help in protecting them, and he founded what is today known as Rainforest Expeditions with two other partners."

TRC's first clients were heavy-duty photographers and bird watchers who slept on a platform with makeshift mats (called "lengua de gato" or cat's tongue because of their thinness" under mosquito nets. There was no latrine so the guests would take baths and do their business in the flowing river.
Today TRC boasts an 18-room lodge, eight shared bathrooms, and surrounding forest trails encompassing a combined web measuring about 20 kilometers and offering access to a range of wildlife habitats from bamboo forests to terra-firma forests, and riverine beds to palm swamps.

Frank, who has been with Rainforest Expeditions for almost six years, agrees that the company has come a long way from its humble beginnings, and that the most significant progress has been on the forefront of conservation and social enterprise.

"I am really proud to be able to say that Rainforest Expeditions started ecotourism in this area of Peru," he beams. "One of the reasons that I really like working here is that, besides being involved in research, the company also has several projects and a cooperation with the local community in this area."

Frank is referring to the indigenous Esa-Eja tribe in the nearby community of Infierno, two hours upriver from Puerto Maldonado, in Southeastern Peru, who also happens to be Rainforest Expeditions' business partner.

"Rainforest Expeditions also runs another lodge called Posada Amazonas, which is closer to Puerto Maldonado and is partly run by the community. They have an agreement with the company wherein 60% of the profits stay within the community, and the rest goes to Rainforest Expeditions for profit and maintenance of the facilities," Frank explains.

Besides TRC and Posada Amazonas, Rainforest Expeditions also runs Refugio Amazonas, the "luxury" lodge option to TRC's more adventurous and Spartan vibe, and the company is currently undergoing research to build a fourth lodge. Whatever the theme, though, the team behind Rainforest Expeditions seems to have their formula down pat.

In all of the lodges, the rooms and structures are built to blend in with the environment, using traditional materials. A unique aspect of all of the rooms is that they have left the fourth wall vacant, opting instead for a waist- high balcony that opens out into the rainforest. This design is a singular feature for all Rainforest Expeditions lodges and gives guests the distinct feeling of being in closer contact with the forest but with the comforts of a hotel room.

Needless to say, we never had to look very far for wildlife. We would barely be ten steps from the entrance to the lodge before a strange new insect, a well-camouflaged snake, or a majestic bird would hold up our group. Boat rides were punctuated by sightings of capybaras or tapirs. Our well-versed and knowledgeable guides seemed to know the jungle like the backs of their hands, and could expertly field our queries and feed us tidbits of useful trivia.

I woke up every morning to the majestic sounds of the orchestra that was the Amazon rainforest just behind my bedpost: birds screeching intermittently, giant crickets chirping in a rising and falling crescendo, and the strange gurgling sounds of howler monkeys screaming at each other from the treetops.

Some days I would wake to find a rogue macaw poking around in my clothesline, probably hunting for some of the nuts and dried mangoes I would stuff into my pockets and take on hikes. And even though we had been warned to keep food locked up or stored safely in plastic bins or run the risk of getting our rooms invaded, one particular day we awoke to a mighty ruckus coming from a neighboring room: a stubborn guest had found some curious possums snooping (successfully) in his backpack for some chocolate bars.

A few days before the end of our trip, the host and humid skies finally broke and poured cool, wet rain on the TRC grounds. It didn't last very long, but while it poured, I got the sense that the entire forest had gone quite still. I stood for a long time watching the rain from the shelter of TRC's entrance hall, admiring the way the sun caught on the lodge's thatch roofs and appreciating the cold, damp breeze the rain blew in, and not for the last time, I marveled at this little piece of paradise right smack in the middle of the Amazon jungle that Rainforest Expeditions had somehow nurtured, protected, and turned into a home. For information on Rainforest Expeditions and its various tours and projects, visit www.perunature.com
February 11, 2015

Rise of the Orb-Weaver Spiders

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Spiders! They’re creatures you’re almost certain to see in the Peruvian Amazon, whether you like it or not.
A spined Micrathena spider, belonging to family Araneidae

Spiders have been around for hundreds of millions of years and have adapted to almost every corner of the earth. As predators, they have developed a very unique strategy of producing webs made of silk to catch prey and one particular group, called the orb-weavers, create spiral round-shaped webs to ensnare their flying victims.

An orb-weaver in the genus Nephila, family Araneidae

The Deinopoidea (the cribellate orb weavers) and the Araneoidea (the viscid silk orb weavers) are two groups of spiders that make geometrically similar orb webs and for a long time scientists thought that orb weavers were one distinct lineage. However, a recent study out of Harvard proves that this is false: the orb weavers are in fact nonmonophyletic, meaning they do not share a single origin.

The net-casting spider, a cribellate orb-weaver in the family Deinopidae

The researchers utilized thousands of genes from various spider species and conducted a phylogenetic analysis, which looks at the evolutionary relationships among groups of organisms. Here’s how it works in a nutshell:

  • They used next-generation sequencing, a technology which allows scientists to rapidly sequence the genetic material of an organism.
  • For each spider specimen, the messenger RNA (mRNA) was extracted, complementary DNA (cDNA) libraries were constructed, and samples were run using an Illumina platform, thus sequencing and generating a huge amount of genetic data.
  • The data was then used to construct a phylogenetic tree, which represents the evolutionary relationships among spiders.
  • After all the hard work, the researchers produced the most comprehensive analysis to date for investigating spider evolution.

How could you not love that spidey-face?

The controversy over a single or a convergent origin of the orb web goes back to at least the 1880s. Research, primarily based on behavioral and morphological data, have supported a single origin of the orb web, but this new study clearly shows that Deinopoidea is not closely related to Araneoidea.

Orb-weaver (Araneidae) enjoying a freshly caught grasshopper

Thus, orb webs appear to have evolved convergently in Araneoidea and Deinopoidea. Either that, or the orb web is an ancestral phenomenon and has been lost in all lineages except Araneoidea and Deinopidea. This is very cool research, and only time will tell what new insights scientists come to gain on arachnid evolution.

Citation: Fernandez R, Hormiga G, Giribet G. 2014. Phylogenomic analysis of spiders reveals nonmonophyly of orb weavers. Current Biology 24:1772-1777


-Aaron

 
 
 
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