Stories
Mystery of the Yellow Bulbs: Discovery in the Amazon of a New Caterpillar-Ant-Parasitic Plant Relationship
“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…I didn’t know that what was in front of my eyes was an ant-caterpillar parasite relationship.
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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 onto 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 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 fieldwork 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 the tree with yellow bulbs
I assembled the photos from the trip and started 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 the 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 these criteria.
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
In January, my colleague Phil Torres visited this site and checked out the caterpillars. You can see the yellow bulb flowers are more developed at this point.
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 describe 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?
Perhaps the yellow wing marking helps the butterfly blend in with the yellow parasitic plant and reduces predation by birds. While this hypothesis needs further attention, the similar wing pattern and observed host plant could lend support to the idea of a long-term co-evolutionary relationship between the flowering endoparasitic herb and the Terenthina terentia butterfly. In any case, we’ll attempt to continue to pick apart this fascinating Amazon mystery which will undoubtedly result in even more questions!
By Aaron Pomerantz
Entomologist. 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, 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
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What our guest say
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- Valuation Excellent
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I am normally not a nature-oriented person but spending a few days in the rainforest was mind-blowing. Our guide, Juan Carlos, was knowledgeable, passionate about his work, and a fun person to go on a several hours long hike to boot. He made sure we were taking the activities at our own pace, answered all our questions and had a seemingly endless knowledge of the plants and animals. The lodge is located in a protected area of the rainforest and as a result, the biodiversity is amazing and the staff are very respectful and protective of the wildlife. For a note on the lodging, late september is the end of dry season and also the hottest time of year. If I were to come back, I would upgrade to a room with a fan as there is no AC in the facility. Lodging was clean and I personally enjoyed the chance to unplug and sleep so close to nature. Without hyperbole this was a once in a lifetime experience and I cannot recommend it enough. Read all
We had the experience of a lifetime at Posada Amazonas! For our first trip ever to Peru, we wanted to see as much of the country as possible, and started our journey here. Everything went seamlessly- from the pick up at the airport, check in at the office, to the delicious lunch on the boat during our transfer. The next 3 days were filled with wonderful experiences including the canopy hike, oxbow lake cruise, sunset cruise and more. Luis was our guide extraordinaire. His knowledge and ability to spot interesting flora and fauna were amazing. The rooms are clean and spacious and perfect to experience the jungle. You haven't lived until you are awakened by the calls of howler monkeys at 4:15am! Highly recommended! Read all
We had a truly amazing time at Tambopata Research Center and its sister lodge, Refugio. Days were filled with long walks in the jungle to see all the incredible wildlife and plant life, the evening talks with the researchers were thoroughly enjoyable and inspiring, and meals with like minded travelers were a pleasure. Our rooms were extremely comfortable and well laid out, the food was varied, healthy and tasty, and the staff really went out of their way to ensure we had everything we needed and that our stay was going well. Truly couldn't recommend this experience more. Read all
My husband and I recently had the opportunity to visit the Tambopata Research Center in the Amazon rainforest, and it was truly an unforgettable experience! We did the 5 day, 4 night experience, which was so worth it. I personally think this is the perfect amount of time as it gave us the flexibility to have more opportunities to see wildlife, but also moments of relaxing at the lodge. We booked the trip through Tambopata Travel, with Mike. He was extremely helpful, very organized, and answered all 5 million questions I had haha. He was a very effective communicator and I would recommend anyone and everyone use him to help plan your rainforest experience. Before I get to my review, my only recommendation to the center would be for them to incorporate more of a variety of activities. A majority of the available activities are equivalent to walking around the rainforest looking for animals and learning about the surroundings. Which was amazing to me, but could lead to boredom for some. Thankfully, we had out guide Timo who made every walk through the rainforest interesting. Reaching the lodge does take about 3.5 hours, but if you embrace this part of the journey it only makes everything better. Once we arrived, I found the lodge to be absolutely amazing given its remote location. There will be bugs and there will be loud animal sounds, I think it’s important to remember we are guest in these animals home. Having spent 11 days in Peru prior to this trip, I can confidently say that the food at the lodge was the best we had consistently enjoyed throughout our travels. We also had the opportunity to work with other guides in Peru, all of whom were booked through reputable companies, but none compared to our guide, Timo, in terms of his English proficiency and extensive knowledge. The bar manager was also a highlight; he was very knowledgeable about alcohol and offered great recommendations and was able to make a variety of drinks based on what we were wanting to experience. All of the staff at Tambopata were very friendly and always had a smile on their face, especially the busser, I unfortunately missed his name, but he was great and so friendly. From start to finish, the trip was filled with incredible moments, largely thanks to our amazing guide, Timo. Timo was hands down the most knowledgeable guide I have ever encountered. His expertise about the rainforest was impressive, and he had an uncanny ability to spot wildlife that we would have completely missed without him. It was raining one day and we were willing to go out in the rain and Timo was right there with us. We had the chance to see a wide variety of animals, far exceeding my expectations.Timo also provided us with extensive knowledge about the plants and trees, helping us to understand the ecosystem as a whole. I was seriously blown away by how much he knew about the rainforest. Timo’s insights made the experience not just about the wildlife we saw, but also about the profound interconnectedness of life in the rainforest. We also appreciated Timo’s insight about the nature of wildlife viewing in the rainforest; some days were bustling with activity while others were quieter. I think it’s important for anyone wanting to travel to the Amazon to remember, this is a vast ecosystem with thousands of acres of wilderness- not a zoo. Overall, my time at the Tambopata Research Center was filled with awe-inspiring moments, and I learned so much about the rainforest. I highly recommend this experience to anyone looking to connect deeply with nature. Just remember to go with the flow and appreciate the rainforest for what it is! Read all
Fantastic lodge and research station deep in the reserve and the Amazon forest far from all visible signs of humanity, dense rainforest teeming with birds, animals, insects - it balances the discomfort of the steamy forest heat and biting insects perfectly with a little luxury when you are not out on excursions in the jungle - exactly what one would want from an Amazon experience. Read all
This lodge is a bit of a splurge, but for me, totally worth it. The staff were, without exception, cheerful, friendly and helpful. Our guide, Dino, was a true professional: a calm presence and a genius at spotting wildlife, and having no more than seven people in our group at all times was a plus (the other Rainforest Expeditions lodges have up to ten). We opted for a Comfort Room, and it was lovely; spacious and attractive, with a hammock and a terrific shower. The biggest surprise for me was the food, which was consistently terrific. Finally, it is clear to me that Rainforest Expeditions is truly committed to environmental preservation and giving back to the local community. As for the rainforest itself, it was interesting and we saw lots of wildlife, but don't expect it to be like an African safari. You can walk for a long time without seeing much, and often the animals are far way or well hidden (this is one reason group size matters; we often took turns looking through our guide's high-powered telescopic lens). Also, your experience will depend a lot on the weather. Two of the days we were there were quite nice; the other two were oppressively, stultifyingly hot and humid. Read all
This lodge is a bit of a splurge, but for me, totally worth it. The staff were, without exception, cheerful, friendly and helpful. Our guide, Dino, was a true professional: a calm presence and a genius at spotting wildlife, and having no more than seven people in our group at all times was a plus (the other Rainforest Expeditions lodges have up to ten). We opted for a Comfort Room, and it was lovely; spacious and attractive, with a hammock and a terrific shower. The biggest surprise for me was the food, which was consistently terrific. Finally, it is clear to me that Rainforest Expeditions is truly committed to environmental preservation and giving back to the local community. As for the rainforest itself, it was interesting and we saw lots of wildlife, but don't expect it to be like an African safari. You can walk for a long time without seeing much, and often the animals are far way or well hidden (this is one reason group size matters; we often took turns looking through our guide's high-powered telescopic lens). Also, your experience will depend a lot on the weather. Two of the days we were there were quite nice; the other two were oppressively, stultifyingly hot and humid. Read all
We had an amazing time during our trip to the Tambopata Research Center. The staff make your stay as comfortable as possible, and the food is delicious. From the moment they collect you at the airport, you don’t have to worry about anything - you’ll be in good hands. Our guide, Boris, did an incredible job of planning our daily activities, and we were spoiled to see and learn about the incredible wildlife - parrots, macaws, monkeys, capybara, innumerable insects, and more! This is a fantastic trip is highly recommended if you are keen on science, nature, and not too fussed about some pretty big bugs! We did a 3-night, 2-day trip (with a travel day on both sides), and would recommend one more day if you can swing it! Read all
This is not a resort but rather a very nice and comfortable eco lodge to view wildlife with friendly and knowledgeable staff. Keep in mind that there is a lot of walking and stairs (almost 0.5 miles) to get to the lodge from the water transport river bank where you are dropped off. The clean spacious rooms are open air concept with mosquito nets for the beds and you can listen to rainforest creatures all night. The activities they offer are diverse (e.g., night hikes, water excursions to see caimans, otters and bird watching, visit to local farm and 40 meter observation tower). You are fed well with breakfast, lunch and dinner buffets. Many thanks to our tour guide Luis M. for his extensive knowledge of the rainforest and keen eyes/ears to find hidden creatures while keeping our group safe. Read all
Fint och trevligt ställe inne i regnskogen. Maten var enkel men god, serverat som buffé. Vatten från egen brunn fanns för påfyllning i medhavda vattenflaskor (fanns att köpa om man missat). Kaffe och te fanns alltid tillgängligt men var oftast kallt och svagt. Mycket häftiga rum som är helt öppna mot naturen på en sida. Var beredd på besök av smådjur och insekter. Gästerna fick komma överens om vilka aktiviteter vi ville genomföra med guiden på plats. Turerna var bra men med mycket tidiga starter. För oss som hade värmebölja med temperaturer uppåt 40 grader passade detta bra. Read all
Our 3-night stay at the Tambopata research was an experience we will never forget. Everything was well coordinated starting with our pickup at the airport. We then took a 10 min bus ride to the Rainforest Expeditions office where a busload of us all repacked our stuff into 30 lb duffel bags. The remainder of our items stayed at the office. Next, we got back on the bus for a 90-minute ride to the boat dock. Along the way, we had a box lunch and had an overview of the area and our upcoming days. Once on the boat, the guides slowed down for wildlife photo ops of capybaras and the many birds we saw. When we arrived at the lodge, Mary gave an overview of the facility while our bags were taken to our room which was a 10-minute walk from the main lodge/dining area on an elevated boardwalk in the rainforest. The room as advertised was open on one side to the rainforest and yes, we did have some nighttime visitors, but the mosquito netting kept them off us. The room was spacious and well-appointed with a fridge, ceiling fan, water, etc. At dinner we met our own personal rainforest guide – Timo. We made our plans for the next day which included a 5AM boat ride to the clay lick where we saw the most amazing macaws. Timo was very knowledgeable, fluent in English and well equipped with a telescope which provided some great pix even with using just an iPhone. Timo also took us on several hikes around the facility and up to the top of the canopy tower where we saw various species on monkeys and more birds. Each evening there were lectures presented by the researchers on various topics. Then there was the food! Each meal was freshly made and well prepared. Quite a variety for all tastes. The food is amazing and goes quickly so be sure to load up your plate. And the bar had a decent variety of beer, wine and liquor! We spent more at Tambopata than we normally would, but I can say it was definitely well worth it!! Read all
Had an amazing stay of 3 nights here. Guide (Lucia) was fantastic, even having a phone attachment to allow you to take photos through her telescope and get fantastic shots, and much of the trip was solo with her. The lodge had blazing fast wifi, mix of craft beers, and was very comfortable (as long as you don't mind the odd butterfly or frog wandering into your room). Friendly service and really well organized w/ lots of variety of things to do - I happened to stumble across a giant Harpy Eagle right outside the lodge, just incredible. Only thing that could be improved is more variety of food and condiments to spice it up, but it is in the middle of the rainforest after all Read all
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