We Discovered & Published a New Butterfly Life History

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It was late 2014 when Phil Torres first showed me the photos from his recent trip to the Peruvian Amazon. Among them were amazing images of the tropical wildlife, from brilliant macaws to elusive pumas. But there were a few critters in that album that stood out to us in particular. Flipping through his camera, Phil said something to the effect of, "Check out this butterfly dude, it hangs out with ants on bamboo."

You can watch the video Phil and I put together on this discovery

After Phil showed me a few more photos, it was clear that this butterfly-ant interaction was not due to chance...something was going on here.

Multiple butterflies (both male and female) gathering on a bamboo stalk in the presence of ants.

Up-close shot of the butterflies and ants feeding from the sap secretions emitting from the bamboo shoot.

Phil and I both have backgrounds in entomology, and yet we had never seen anything like this before. I mean sure, we knew that some butterfly larvae have symbiotic relationships with ants, known as myrmecophily. This is well documented, as many of the caterpillars that associate with ants have special organs that secrete sugars and amino acids. The ants get a sugary nutritious meal from the caterpillars and, in return, the fragile caterpillars get personal ant bodyguards which defend against predators and parasites. But this is not the case for the adult butterflies, which usually have to evade ants, lest they become their next meal.

One more thing, Phil said, "Look at the three red spots on the butterfly wing. Kind of looks like the ants they're with on the bamboo. Maybe it's some sort of mimicry."

Alright, now I was really interested. The butterfly appears to be a known species, Adelotypa annulifera, but these pictures could be revealing an undocumented observation for this butterfly interacting with ants and a potentially new wing-mimicry pattern. Super cool, I thought, but there was just one problem: we know little about this butterfly beyond some dead pinned specimens. What is its life cycle? Where do the larvae develop? What do the larvae even look like? In other words, next to nothing was known about the life history of this butterfly. So to solve this mystery, Phil and I decided to collaborate. I was making a return trip to this exact field site in the coming months, so I set out to uncover the missing pieces of this puzzle.

Overlook of the Tambopata River at our field site in Southeastern Peru.

Overlook of the Tambopata River at our field site in Southeastern Peru.

The challenge with this type of fieldwork is that the Amazon rainforest is very big, and the critters we are looking for are very small. Since Phil observed the butterflies on bamboo, I ventured out to the same habitat, a trek from the Tambopata Research Center. I recall the jungle seemed particularly hot, humid, rainy, and muddy during that expedition, but I was determined to find our caterpillars and butterflies.

After hours of hiking through the Peruvian Amazon and getting continuously soaked by rain downpours, I found myself in the bamboo forest where we knew our butterflies liked to hang out. After checking dozens of bamboo plants, things seemed futile, as I wasn't finding any signs of our butterflies of interest. But persistence is the key to field work. I then saw a young bamboo shoot poking out of the mud, and noticed a leaf near the base of the bamboo, close to the ground.

Bamboo stalk with a leaf wrapped around the shoot near the base of the plant.

Bamboo stalk with a leaf wrapped around the shoot near the base of the plant.

I pulled the leaf back and to my utter shock, found myself staring directly at two caterpillars nestled against the bamboo, and an agitated ant hovering over the Lepidoptera larvae. My heart was pounding - did I really just find our caterpillars in this vast rainforest!? Clearly they were myrmecophilous, as the ant was trying to protect them.

First observation of the caterpillars with an ant bodyguard.

First observation of the caterpillars with an ant bodyguard.

Although excited from the find, I knew the job wasn't done. This could be any species of caterpillar, so I knew I had to watch them turn into pupae and finally into adults in order to truly confirm that these belonged to the same butterfly species. I continuously checked up on the caterpillars at this spot and took numerous photos and video. After a couple of days, I found our little critters in the same location, but this time they had transformed into pupae! At this point, I gently collected them and brought them to a small insect cage at the Tambopata Research Center to see if they would emerge as butterflies. I had my fingers crossed, hopefully they would survive to adulthood.

The caterpillars later turned into pupae.

The caterpillars later turned into pupae.

Fast forward, and one day I walked past the little insect cage when I noticed some activity. Wings fluttering. One of the pupae had successfully eclosed! So the moment of truth, what butterfly was it? My jaw dropped when I noticed it was, in fact, the same butterfly (Adelotypa annulifera) that Phil had taken pictures of previously. What this means is, we had just completed the entire life cycle of the butterfly, from egg to larvae to pupae, and finally adult. We now felt that we had enough material to write this up as an official scientific publication.

Figure 1 from the publication, the immature life stages of the butterfly and their association with ants. (A) Eggs with Megalomyrmex ant, (B) First instar larva with Ectatomma tuberculatum ant (C) Mid-instar larva with Pheidole ant (D) Mid-instar larvae with bullet ants (E) Final instar larva with E. tuberculatum ant (E) Pupae.

Figure 1 from the publication, the immature life stages of the butterfly and their association with ants. (A) Eggs with Megalomyrmex ant, (B) First instar larva with Ectatomma tuberculatum ant (C) Mid-instar larva with Pheidole ant (D) Mid-instar larvae with bullet ants (E) Final instar larva with E. tuberculatum ant (E) Pupae.

Figure 2. Dorsal (left) and lateral (right) views of early instar caterpillar.

 

 

 

 

 

Figure 3. Final instar larva (left) and pupa (right).

 

 

 

 

 

Figure 4. Adult Adelotypa annulifera interactions with ants on bamboo. (A) Ants touching the butterfly wings with antennae. (B) Ant crawling on butterfly wing. (C) Ants touching butterfly abdomen. (D-E) Butterflies and ants utilizing extrafloral nectary resources on bamboo. (F) Butterfly drinking bamboo fluid from the ant.

Figure 4. Adult Adelotypa annulifera interactions with ants on bamboo. (A) Ants touching the butterfly wings with antennae. (B) Ant crawling on butterfly wing. (C) Ants touching butterfly abdomen. (D-E) Butterflies and ants utilizing extrafloral nectary resources on bamboo. (F) Butterfly drinking bamboo fluid from the ant.

Figure 5. The butterflies and their putative wing pattern mimicry. (A) male butterfly (left) and female butterfly (right) perched on bamboo shoot in presence of red ants. Views of the wing pattern (B) ventral (C) dorsal and (D) lateral.

Overall, it was really exciting collaborating with Phil to discover and publish this life history, which is completely new for this genus of butterflies. In addition, we think the fact that butterflies steal a resource from the ants and let the ants crawl all over them indicates that some complex chemical signaling is going on. Perhaps the butterflies are utilizing a pheromone from their larval stage, potentially allowing the butterfly to take advantage of the ants, which would normally tear a fragile butterfly to shreds. The three red spots on the butterfly wing also look strikingly like the red ants (at least to us) and perhaps serve as a form of mimicry (if a butterfly looks like red ants that bite and sting, a bird may be less inclined to eat it). However, it should be noted that these are just our hypotheses at the moment and, like any hypothesis, should be rigorously tested before we can claim to back it up. We hope to do so, because there most certainly seems to be more to this incredible tropical butterfly than meets the eyes. Stay tuned...

Phil and I enjoying a boat ride along the river in the Amazon rainforest.

For more info, you can download the PDF here: Torres_Pomerantz_Adelotypa_Publication_2016

One more fun fact: it was actually during this trip that I accidentally discovered a totally new, yet unrelated, butterfly-ant relationship. The jungle is full of endless surprises -

[embed]https://www.youtube.com/watch?v=Z1a4zIjo3uU[/embed]

Mystery of the Yellow Bulbs, video and blog post http://blog.perunature.com/2015/11/mystery-of-yellow-bulbs-discovery-of.html 

-Aaron

My Instagram: @NextGenScientist & Twitter: @AaronPomerantz

Phil's Instagram: @phil_torres & Twitter: @phil_torres

In the Field: Macro Photography, Microscopy & How Butterflies Create Color

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Working in the Amazon rainforest has its challenges. To name an obvious one, it can be difficult to take equipment into remote field sites in order to conduct research. Fortunately, we live in an exciting time, as technology is rapidly becoming simultaneously cheaper and more portable. In this post, I want to share a couple tools that I use to document small organisms in the rainforest, including the wing structures of butterflies and moths, as well as discuss the fascinating ways that biology creates color.

Macro shot of a Heliconius butterfly wing. The different colors (oranges, yellows, blacks) are caused by pigment production in each individual scale. MP-E65mm, ƒ/11.0, 1/125, ISO 200.

Macro shot of a Heliconius butterfly wing. The different colors (oranges, yellows, blacks) are caused by pigment production in each individual scale. MP-E65mm, ƒ/11.0, 1/125, ISO 200.

For starters, digital SLR cameras and macro lenses are powerful handheld tools that I use to document the biological diversity of tiny creatures that inhabit South America. I'm currently using a Canon 70D camera body equipped with the shockingly powerful MP-E 65 Macro lens. This lens is truly a macro beast, magnifying up to 5 times (aka a magnification ratio of 5:1) and allows me to get sharp images of microscopic structures, such as butterfly wing scales. For shots of the whole organism, I typically use the Canon EF 100mm f/2.8L macro lens, which I really love for its versatility and sharpness. In combination, the 100mm and MP-E 65 are a fantastic combination for macro photography in the field, allowing me to document small organisms such as insects, as well as zoom-in even closer to resolve  specific regions.

Here's a video explaining how these butterflies create color & using the Foldscope to investigate scale structures.

At our remote outpost in Sumaco, Ecuador, tinkering with my camera to photograph insects and butterfly wing scales.

At our remote outpost in Sumaco, Ecuador, tinkering with my camera to photograph insects and butterfly wing scales.

s an entomologist in the Amazon, I've been able to study a broad range of fascinating creatures, from Glowing Worms to Tentacled Caterpillars. More recently, I've become enthralled by the wings of butterflies and moths, and more specifically am curious about how these organisms produce such an incredible array of colors.

Macro of a Morpho wing, note the blue scales which do not contain any blue pigment. They contain nanostructures that bounce light back at the blue wavelength, a form of 'structural color'.

Macro of a Morpho wing, note the blue scales which do not contain any blue pigment. They contain nanostructures that bounce light back at the blue wavelength, a form of 'structural color'.

Butterflies and moths belong to the order Lepidoptera and all members have scales covering their bodies and wings (in Latin, lepis means scale and ptera means wing). With over 180,000 described species, the Lepidoptera are not only diverse in their numbers but also in their colors. Their color arises due to the nature of the scales that they produce and can be due to pigmentation as well as structural color. Whatever the origin, color results from an interaction between light and matter.

Like beautiful painted tiles, the scales on this Phantom butterfly range from shades of pink to entirely transparent. MP-E65mm, ƒ/11.0, 1/125, ISO 200.

Like beautiful painted tiles, the scales on this Phantom butterfly range from shades of pink to entirely transparent. MP-E65mm, ƒ/11.0, 1/125, ISO 200.

Owl Butterflies mating. The large eye spot on the hindwing is thought to startle potential predators like birds, a form of Batesian mimicry in which a harmless organism acquires protection by resembling a threatening animal. 

Owl Butterflies mating. The large eye spot on the hindwing is thought to startle potential predators like birds, a form of Batesian mimicry in which a harmless organism acquires protection by resembling a threatening animal. 

But even with the best macro lenses, it's still tough to resolve the scale structures on the wings of these insects. To get really close, we need to get into microscopy. But any of us familiar with using a microscope know that they are big, cumbersome, expensive pieces of equipment - not exactly compatible with field work. However, last year I came across an ingenious invention by a lab at Stanford, the Foldscope (an origami foldable microscope that costs about one dollar).

Some of the tools in my "mobile lab" kit: a foldable microscope, a DSLR camera with macro lens, a handheld gene sequencer, and my mobile phone.

Some of the tools in my "mobile lab" kit: a foldable microscope, a DSLR camera with macro lens, a handheld gene sequencer, and my mobile phone.

In the past I've posted about using the Foldscope to investigate small critters in the Amazon, but I've recently started using it to look at butterfly and moth wing scales, and it actually does a fantastic job.

An Amber Phantom butterfly with transparent wings. Combining macro photography and the Foldscope, allowing us to see the different scale structures that make up the colored and transparent regions of the wing.

An Amber Phantom butterfly with transparent wings. Combining macro photography and the Foldscope, allowing us to see the different scale structures that make up the colored and transparent regions of the wing.

Here is a dirunal moth in the family Uraniidae, notice how the scales that appeared green shift to a violet/purple color under the Foldscope. I imagine that the colored scales have microstructures that produce green wavelengths under normal sunlight conditions and changing the incoming light in the microscope has shifted the wavelength output. This is the reason Morpho butterflies appear iridescent blue, due to the structure of their nanoscales (called mullions).

Compilation of butterfly wing scales through macro photography and Foldscope microscopy, all taken while in the field in the Amazon Rainforest.

Compilation of butterfly wing scales through macro photography and Foldscope microscopy, all taken while in the field in the Amazon Rainforest.

Hope you enjoyed, you can check out more updates via Twitter, Instagram, and YouTube!

-Aaron

Discovering a New Butterfly-Ant-Parasitic Plant Relationship

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“Huh, that’s weird”, I muttered as I trudged through the mud in the rainforest. Even though the sun was setting, it was still hot and steamy, and sweat was dripping into my eyes as I stared at a tree with bizarre yellow outgrowths...

Watch the video "Mystery of the Yellow Bulbs: Caterpillars, Ants & Parasitic Plants"

Some sort of fungus? That was my first thought. After all, I've seen tons of strange looking fungi in the Amazon by now. But something about these yellow bulby-looking things piqued my curiosity, so I walked up to take a closer look.

A tree covered with strange yellow bulbs in the jungle

Inspecting them closer only made things more confusing. They didn't really look like fungi, at least not like any I had ever seen before. Was it a fruit produced by the tree? Plant lenticels? I started to take some pictures.

A closer look at the mysterious yellow "bulbs"

That's when I noticed something really interesting. As I scanned the tree's alien protuberances, my eyes locked on to something I wasn't quite anticipating: caterpillars! I had definitely never seen, or heard of, anything like this before. They appeared to be munching away on the yellow bulbs.

An unknown caterpillar eating one of the yellow bulbs

I quickly noticed there were also ants surrounding these caterpillars. The ants were not attacking the delicate butterfly larvae, so this had to be some sort of symbiotic relationship between the caterpillars and ants. While I had little idea at the time what I was looking at, my background in entomology was telling me one thing: this was something cool.

An ant, Ectatomma tuberculatum, guarding a caterpillar

Always gotta show a finger for scale

By this point I had returned to the tree with my colleague, wildlife photographer Jeff Cremer. We took several shots of the caterpillars, ants, and yellow bulbs. This kind of mutualistic caterpillar-ant relationship is known as myrmecophily, and has interested scientists for a long time. Caterpillars belonging to the family lycaenidae have a special structure known as the dorsal nectary organ, which secretes sugars and amino acids. This sweet, nutritious reward is what keeps the ants around and in return, the ants protect the caterpillars by driving off hungry predators and parasitoids.

An attendant ant tapping the caterpillar and receiving a nectar droplet. Filmed thanks to the help of Chris Johns

As I was inspecting this bizarre caterpillar-ant interaction, I noticed something flutter just above my head. A butterfly! Not just any butterfly, I could immediately identify it as a lycaenid and it had a distinct yellow spot on its hind wing that looked remarkably like the yellow bulbs. Was this the adult of the caterpillars!?

A butterfly with a yellow wing spot lands on the tree

Ok, Homework Time

I wrapped up my field work and headed back to the states, but I was dying to figure out what was going on here. To recap, we observed:

  • Mysterious yellow bulbs growing on a tree
  • Caterpillars eating the yellow bulbs
  • Ants taking care of the caterpillars
  • Butterfly with yellow wing spot lands on tree with yellow bulbs

I assembled the photos from the trip and starting emailing the top butterfly experts as well as botanists. The responses I received were mostly along the lines of "I've never seen anything like this before" and "there's nothing published on the life history of the butterfly". Ok, so it seemed like we were on to something new here.

With the help of some experts, we were able to identify the butterfly as Terenthina terentia, which belongs to family Lycaenidae. While this family contains around 6,000 species, the Neotropical lycaenids are still only partially known and poorly studied (Pierce 2002). Many species of lycaenids are known to engage in relationships with ants (aka myrmecophily) so our caterpillars definitely fit this criteria.

Filming this strange caterpillar-ant-parasitic plant relationship

Filming this strange caterpillar-ant-parasitic plant relationship

Several botanists emailed my pictures around to their colleagues until we were finally able to ID the yellow bulbs as a "very unusual and rarely seen" parasitic plant belonging to the family Apodanthaceae. Ever heard of that? Yeah, me either.

Apodanthaceae is a small family of parasitic plants that live inside other plants and they only become visible once the flowers burst through the bark (Bellot 2014). The species we found is possibly Apodanthes caseariae and there is little known about their ecology, what pollinates them, or how they infect their host plants. Our observations appear to be the first record of an insect utilizing Apodanthes as a host plant. The strange yellow bulbs of this plant appear to emerge once a year around October through January and then fall off.

The yellow bulbs later identified as a rare flowering parasitic plant

What's the Take-Home?

Although this species of butterfly, Terenthina terentia, was described over one hundred years ago, we knew essentially nothing about how it lived its life until now. In other words, we helped to described its life history by documenting the larval stages, host plant, and ant-associated behavior. By observing and studying this complex relationship, we can gain more insight into the diverse array of biological interactions in the Amazon rainforest.

Compilation shots of a potential Terenthina terentia caterpillar showing its morphology

However, our work is far from over and many questions still remain. Is this the butterfly's only host plant? How does it know when the parasitic plant is emerging and how does it find the yellow bulbs? What purpose does the butterfly's yellow wing spot serve? We'll attempt to continue to pick apart this fascinating Amazon mystery which will undoubtedly result in even more questions!

-Aaron Pomerantz, Entomologist

[This post originally appeared on the PeruNature.com blog http://blog.perunature.com/2015/11/mystery-of-yellow-bulbs-discovery-of.html]

You can follow Aaron for updates & get in touch on Twitter @AaronPomerantz

Special thanks to colleagues in and out of the field who assisted with this project, especially Jeff Cremer, Frank Pichardo, Chris A. Johns, Phil Torres, Christie Wilcox, Jason Goldman, Nadia Drake, Trevor Caskey, and Alex Gardels. Thanks to Andrew Warren, Alex Wild, Naomi Pierce, Adrian Hoskins, Sidonie Bellot and Robert Robbins for help with insect/plant identifications and expert input.

References

Bellot S, Renner SS (2014) The systematics of the worldwide endoparasite family Apodanthaceae (Cucerbitales), with a key, a map, and color photos of most species. PhytoKeys 36: 41-57

Pierce NE, Braby MF, Heath A, Lohman DJ, Methew J, Rand DB, Travassos MA (2002) The ecology and evolution of ant association in the Lycaenidae (Lepidoptera). Annual Review of Entomology 47: 733-771