Wildlife Photographer of the Year Q&A: Bug filling station, Behaviour: Invertebrates highly commended

We are continuing our series of Q&A posts about my Wildlife Photographer of the Year winning images, and this time I will be reviewing Behaviour: Invertebrates highly commended: Bug filling station.

Bug filling station. Wildlife Photographer of the Year 2021, Invertebrate Behaviour category highly commended. Predatory stink bug nymph (Euthyrhynchus floridanus) feeding on a moth caterpillar. Mindo, Ecuador

You can watch the part when it appears in the awards ceremony here (timestamped)

Out of my winning images, “Bug filling station” received the least attention and was skipped by many of the reporting media outlets. I think it is a shame, because it tells an interesting story of opportunistic survival.

“It’s a gruesome scene but it’s a remarkable piece of behavior”

What is so special about this photo?
The photo shows a small bug nymph feeding on a much larger moth caterpillar that was in preparations for pupating on a tree trunk. However, there is more depth to this story. The caterpillar is most likely a species of a tiger moth, which are characterized by having thick barbed hairs or spikes for protection against predators and parasitoids. As you can see, it didn’t really help the caterpillar in this case, for two reasons. First, the caterpillar is resting inside a very thin and poorly constructed cocoon, these are the black silk threads that can be seen in the photo. This cocoon is spacious and open because the cloud forest is a very wet environment. A typical cocoon with high-density spun silk will absorb rainwater and drown the pupa inside, whereas an open cocoon drains water better. Even though it is a thin cocoon, the caterpillar is still trapped inside and cannot leave. Second, pupating caterpillars are helpless and cannot defend themselves, as they lose the ability to walk prior to pupation, along with most of their senses. Therefore, the caterpillar is essentially defenseless at this stage, and indeed many predators and parasitoid insects seize this opportunity to attack.
Now the small bug nymph enters the picture, and decides to take advantage of the immobilized caterpillar by piercing its body with its proboscis and sucking its juices while the caterpillar is still alive. It is a great opportunity for the bug, because it can stay next to the caterpillar and feed as long as it wants or needs, without worrying about the prey escaping or the food supply running out.

Can you elaborate more about the bug’s mouthparts? I can’t understand what I am looking at.
The hemipteran proboscis is actually a complex system of mouthparts for sucking. The liquid food travels inside the narrow tube seen at the top of the mouthparts complex. This tube consists of the “jaws”; the elongated mandibles and maxillae are layered and arranged as a feeding tube. The folded part seen at the bottom is called labium (lower lip), and functions as a sheath to keep the mouthparts packed tightly together. During feeding this sheath is pushed backwards to expose the tip of the feeding tube and allows the bug to “bite” and start drinking.

What is the size of the bug?
Body length was 8mm. Judging by the size of the wing buds I would say it is two stages (=instars) away from becoming an adult.

A slightly different view of the bug filling station. The Euthyrhynchus floridanus nymph is very small compared to the huge moth caterpillar!

Do you have any behind-the-scenes photos?
I usually travel alone, but surprisingly in this case I do! I spent a few days in the cloud forests of Mindo, Ecuador together with my friend Javier Aznar, taking photos of the beautiful arthropod fauna there. He was kind enough to take my photo.

Me photographing in Mindo, Ecuador (photo courtesy of Javier Aznar)

What else can you tell us about this bug?
The species is the Florida predatory stink bug (Euthyrhynchus floridanus). It is a monotypic species, in other words it is the only species in its genus. It has a wide distribution in southeastern United States and northern Latin America. In contrast to most members of its family Pentatomidae, this species is carnivorous and considered beneficial. It seems to enjoy feeding on many plant pests, as well as other small insects. Interestingly, this species is also gregarious, sometimes attacking prey in groups, although in my case no other nymphs were present in the area. The adult bugs display high color polymorphism, with variable red or orange patches on a metallic dark blue body.

We like the photo! Can we buy a print from you?
Of course. Contact me and I will do my best to assist you.

If you have any questions about my photo that do not appear in this post, feel free to leave them in the comments. I will do my best to answer them.

To read part 1 about “The spider room”, click here.
To read part 3 about “Beautiful bloodsucker”, click here.
To read part 4 about “Spinning the cradle”, click here.
To read part 5 about what to expect when entering a photo competition, click here.