MYSTERY of the yellow Bulbs

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.

If you are looking for the chance to Make Science Happen

Join Wired Amazon

Watch the video ‘Mystery of the Yellow Bulbs: Caterpillars, Ants and 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.

 

 

Tree with Yellow Bulbs in the amazon

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” 

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.

Caterpillar_Eating_Bulb

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.

Ectatomma tuberculatum, guarding a caterpillar An ant, Ectatomma tuberculatum, guarding a caterpillar

Caterpillar_Ant_Finger scale

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.

Caterpilla with antAn 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!?

Butterfly_on_Tree

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.

 

Caterpillar_young_and_ant

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.

 

Tree_bulbs parasite

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 CremerFrank PichardoChris A. JohnsPhil TorresChristie WilcoxJason GoldmanTrevor Caskey, and Alex Gardels. Thanks to Andrew WarrenAlex 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 

Cool right? How you can take action…

Help us make science happen and visit Tambopata with Rainforest Expeditions. If not able to do that, then SHARE what we are doing in the field.

  • What our guest say

    • Valuation Excellent
    • 5/5

Mo Bashagha Feb 2024

nelehkoh9 Feb 2024

Jen101382 Feb 2024

Vigs Feb 2024

Shovan Bhattacharrya Feb 2024

shovan b Feb 2024

Michele Feb 2024

Rahul S Jan 2024

Amina Aziz Jan 2024

Voyage51682856837 Jan 2024

Sundar V Jan 2024

Tina A Jan 2024

A truly magical experience. It’s set in a completely unique location in the middle of the jungle with no other lodges around. The guide we had (Jarinson) was the best, so so knowledgeable, experienced and lovely to spend the time with. The lodge itself is beautiful and food was great too. Would highly recommend. Read all

Interesting bus and river boat rides bring you to Posada Amazonas on the Tambopata River. It’s managed by the Ese Eja indigenous community. Luis M., our guide, helped us observe birds and learn about plants and other animals. A canopy tower, clay lick and oxbow lake are highlights. All personnel are extremely kind and researchers give short lectures in the evening. The food is delicious! Excellent mosquito netting in rooms! Read all

Wow where do I even begin. This was one of the most unique and special experiences we've ever had. You are smack dab in the middle of nowhere, deep in the Amazon jungle. Surrounded by plants and animals of all kinds and some of the most breathtaking scenery you can imagine. And in the company of scientists doing conservation work all around you. The facility is gorgeous beyond belief. Everything is so thoughtfully prepared, from water servers everywhere to comfy couches to hammocks to raised walkways so you can pad around barefoot without feeling like you're going to step on a scorpion. The meals are positively gourmet. They have delicious fresh juice out for you when you come back from your hikes. We spend 2 days there and I genuinely feel like I saw the jungle. 2-3 excursions a day with a private guide to show you everything from plants to birds to animals to a very tall tower where you can watch the sunset over the canopy. We only had 3 people in our group but I believe there can be up to 7. You have the same guide your whole trip so you really get to know them. Johan was our guide and he was wonderful. And I do believe the number of excursions/type/length can be adjusted based on your groups physical ability. The rooms are beautiful and comfy and they help you prepare mosquito netting at night so you can be comfortable. There's a full bar, in the middle of the rainforest. At night there are short (30 min) lectures you can go to if you want where the scientists talk about their work. Fascinating. We loved that the center was very eco conscious and put a lot of effort into being low impact while also offering a truly luxurious experience. That being said. Do yourself a favor and read the web site. This experience will not be for everyone. Ppl posting negative comments here about the heat, bugs, open rooms, etc did not do their homework. You are far, far inside pristine Amazon jungle. It is hot, humid, rainy, and there are bugs. You can expect to use your lovely shower a few times a day to cool off. Fortunately you have lots of down time during the heat of the day to rest under the ceiling fan in your room. There were lots of grasshoppers, moths etc around our room but honestly we didn't have many issues with biting insects or mosquitos despite visiting during the rainy season (we did use bug spray). Your room has one open wall that faces nature. Yes, technically than means someone could see you walking around naked in your room, but you are 15 feet up in the air and facing directly into thick jungle, there is no one out there besides birds and monkeys to see you. They do cut the brush back so nothing except maybe some birds could get into your room. The sounds are magical at night and during the day. It's hot especially if you go during the rainy season as we did. If you hate bugs or can't handle life without air conditioning, this is not for you. Truthfully we had no issues sleeping. Ventilation is another big benefit of the one open wall. Think of this as the glampiest glamping you'll ever do and you will not be disappointed. Read the web site and reviews thoroughly and you won't be surprised. Being good hiking shoes, a lightweight waterproof jacket, refillable water bottle, a hat, binoculars (you can rent them too), bug spray, and sunscreen. Lightweight long sleeved shirts and long pants are essential bc you want to be covered so you won't get bitten or in case you brush up against a nasty plant. We saw monkeys, macaws, capybaras, owls, a caiman, and some cool jungle bugs. The guides even have a telescope you can use to both look at the animals and take great pictures with your phone. once in a lifetime experience in one of the most special and precious ecosystems in the world. Worth every penny and honestly we felt the price was cheap considering what you get. The highlight of our trip to Peru. Thank you so much. Read all

It was our first time in the rainforest and we wouldn't do it any other way. The boat rides on the Madre de Dios and the walks through the rainforests were both exciting and peaceful. Exciting when we spotted wildlife and peaceful as we settled in to hear the sounds and sights of the forest. The lodge was comfortable and the food was great. The research talks in the evenings were a great pre-dinner ritual for us. Do check them out. Saul was an amazing guide - friendly, fun, knowledgeable and very tuned to the rainforest. He could pick up on slight sounds and movements and helped us spot some great wildlife. Read all

TRC is up close with nature deep inside the Peruvian Amazon. If you are a fan of wildlife and love being in the nature this is the place for you. This is an eco lodge, so come with similar expectations. The sound of macaws flying over would make your day. TRC is doing some amazing work on Macaw conservation, the visits to the clay lick would be special. During your journey you would be able to spot a number of animals, birds. Do not miss the guided walks, you would really see a lot of monkeys. If you are a photographer, invest in a good zoom lens ( it will pay you back). The other thing is the amazing staff that take care of you. The food is among the very best I tasted in Peru and they really pamper you. So make sure you walk a lot to burn the additional calories :) Starting from the booking to the pickup in the airport everything is meticulously planned. From Mariella of the booking team, Juan Carlos the guide and Tania, our manager in the hotel everyone was fantastic. Ultimately spotting wild animals is a lot of luck, but this would be a great experience. Rooms: Rooms are large, spacious with wide open balconies, but no monkeys come in ( they strictly don't encourage wildlife feeding). Nearby activities: Lots of them, morning hikes, afternoon hikes, sunset cruise Walkability: You need to walk a bit, so you need to be mobile Food & drinks: Awesome Buffet, great food. Read all

TRC is up close with nature deep inside the Peruvian Amazon. If you are a fan of wildlife and love being in the nature this is the place for you. This is an eco lodge, so come with similar expectations. The sound of macaws flying over would make your day. TRC is doing some amazing work on Macaw conservation, the visits to the clay lick would be special. During your journey you would be able to spot a number of animals, birds. Do not miss the guided walks, you would really see a lot of monkeys. If you are a photographer, invest in a good zoom lens ( it will pay you back). The other thing is the amazing staff that take care of you. The food is among the very best I tasted in Peru and they really pamper you. So make sure you walk a lot to burn the additional calories :) Starting from the booking to the pickup in the airport everything is meticulously planned. From Mariella of the booking team, Juan Carlos the guide and Tania, our manager in the hotel everyone was fantastic. Ultimately spotting wild animals is a lot of luck, but this would be a great experience. Read all

The immersion experience was great. Be prepared though to feel hot and full of bug spray much of the time. Wear hiking pants. Not Lulu leggings (too hot). The guides are great and you can do as much or as little as you want. We saw a lot of animals. Read all

Posadas Amazonas is an eco-friendly lodge that makes a huge commitment to preserving the rainforest for generations to come. The food served (breakfast, lunch and dinner) is fresh and delicious! The staff is extremely knowledgeable and caring. A special shoutout to the lodge manager Cesar for ensuring that we had packed meals for the onward journey when we were delayed by a rain storm. The main attractions apart from the abundant wildlife are the canopy tower and nearby Oxbow lake. The canopy tower gives a great 360 degree view of the rainforest and we were fortunate to see monkeys and macaws from the vantage point. At the Oxbow lake we saw river otters and Caimans and we were able to catch a piranha fish as well. Overall, Posada Amazonas is a great lodge owned and operated by the native communities located in the amazing Amazon rainforest. Read all

I had an amazing time here. I was traveling solo and did 4 days/3 nights through Inca Expert Travel. It was an unforgettable experience! I opted for a group tour for the excursions and am glad I did. Our guide, Boris, was fantastic and made sure we saw as much wildlife as possible. I can't say enough good things about him. The rest of the staff were also very kind. I enjoyed the large variety of fresh food at each meal. I felt safe and well-taken care of the entire time. Read all

TRC was an amazing place to stay. Being in the Amazon rainforest was truly like no other trip I have or will ever take. From arrival we were greeted by staff with cool drinks, warm welcomes. Beautiful main area w bar, sofas, tables,games. Our guide Fernando was SO knowledgeable, interesting, enthusiastic,. We already miss his smile and laugh :) We did every excursion available over our 4 days there. The night hike turned out to be our favorite as we spotted the wandering spider then and many other intersting moths/insects. January is hot and humid, so yes expect to be wet,sweaty. Pack extra bag for wet stinky clothes ... Be ok w insects as no 4th wall in your rooms so at night mosquitio nets do a good job preventing bugs in your bed but when you wake up to use bathroom excpect moths, grasshopppers etc in room. All harmless!! TRC does provide nice rainboots for wet swampy treks.. Read all

A perfect experience in the Amazon. Harry, our guide, made the entire experience very memorable. The food is good, the bar is expensive but good and the support staff were excellent. Tanya, the manager, took care of all our needs and was very supportive the entire stay. Please remember that the rooms are open to the nature and therefore comes with its pros and cons. You wake up with the nature including the mosquitos :) The experiences offered by the Refugio is fantastic and provides a great exposure to the Amazon. Dont miss the Macaw trip. It is just magical. Read all

This is a once-in-a-lifetime experience! From the getgo, it was easy to coordinate our 4-day stay at Tambopata. The booking was all done via email with quick responses, there was clear communication leading up to our stay and even upon arrival the staff was extremely organized (incl. taking our bags and making sure they arrived to our rooms). During our stay the staff was all very friendly and accomodating, the lodge was always clean (actually impressively clean given it is located in the jungle), and the food was great and plentiful. By far the best part of our stay was our tour guide, Saul. Upon arrival, Saul helped us pick our activities based on what animals we wanted to see (using his 10 years of experience). He worked on timing to make sure we can see as much as possible, was extremely knowledgable on the rainforest, the plants, the insects and the animals and noticeably put in the extra effort to find animals. You can tell that he truly loves his job and was always equally as excited to see the animals as us, even though he has seen them thousands of times. He helped us find monkeys, birds, countless insects, lizards, capybaras ect. I am 100% confident our experience wouldn't be the same without him. He even helped us capture these cool photos with only our iphone!! If you are planning to stay are TRC, I would highly recommend asking for Saul as a tour guide, if possible. Read all

Join To Our Newsletter

Write your e-mail

Join
-->