Insect Dogfights: How Aerial Combat Shapes the Patterns of Insect Flight

We might think insects use flight as simply a way to get form A to B. However, along the way they will fly through a congested airspace. In flight, insects battle for prey, territory, and mate, performing dramatic aerial dogfights. This presentation will discuss the patterns of insect aerial pursuit and combat, through the use of 3D reconstruction of high-speed aerial engagements.

Q&A with Dr Samuel T. Fabian

Dr Samuel T. Fabian is a research associate at Imperial College London. His work focusses on the ways in which insects are adapted to chase, fight, and capture each other in the air. The goal of his work is to understand the patterns of insect flight we see around us.

Why do the houseflies do territorial dances under lampshades?

It’s a great question that I don’t have an answer to. It’s something you see all over the world. The particular species that I spoke about, Fannia canicularis, probably started its evolutionary trajectory being in caves, specifically on bat guano or bird poo but why they are so interested in some visual fixture in the ceiling is a very good question. This behaviour, in some way, must increase their access to females. Its relatively common in nature for males to congregate and fight over areas where females are likely to occur. Hill-topping behaviour in butterflies is a good example. But why female houseflies would be likely to be interested in a lampshade is as yet, a mystery. It’s a really good question and it’s such a weird thing for males to do, to spend what days you have on earth, just travelling in circles under a lampshade.

How dangerous are flight interactions between insects of the same species?

I’ve talked about these chases as though they’re life and death situations, and for your predator/prey interactions, it is. But when we are talking about territorial conflicts, it varies. Sometimes, these insects really mess each other up. Demoiselles (Calopteryx sp.) are damselflies found in river habitats and will grab each other’s wings, bite each other and drive each other towards the water. However, in many flying insects it’s much less clear that they possess any way of damaging each other. For instance, with the dragonfly Trithemis aurora, they mostly just fly around each other. In the 500 or so recordings that I have of them dogfighting, not once do they touch. So, it’s a threat that doesn’t materialise into actual physical damage. You could think of it as being a ritualised conflict.

Do you see a lot of variation between different species of insects in how aggressive the flight interactions are?

Yes, there are a lot of differences. Another form of chasing is intraspecific conflict over territory. Some butterflies and dragonflies are aggressive not just towards members of their species but also towards any other members of their group. For instance, peacock and tortoiseshell butterflies chase and battle each other in the early spring, despite being different species. There are also very different behaviours when it comes to aggression. If you watch larger Emperor Dragonflies interacting, their behaviour is quite different to smaller dragonflies– they will actually smack into each other repeatedly. Some species of dragonflies will fly parallel to each other, holding themselves up in a vertical T-pose, defying gravity, and rising gently upwards until one loses and is chased away. There are likely many more interaction types waiting for formal recordings and descriptions, and there’s never been a better time to try and collect this data.

Literature References

Fabian et al (2024) Fabian, S.T., Sondhi, Y., Allen, P.E. et al. Why flying insects gather at artificial light: https://doi.org/10.1038/s41467-024-44785-3
Fabian et al (2022) Avoiding obstacles while intercepting a moving target: a miniature fly’s solution: https://doi.org/10.1242/jeb.243568
Fabian et al (2021) Gravity and active acceleration limit the ability of killer flies (Coenosia attenuata) to steer towards prey when attacking from above: https://royalsocietypublishing.org/doi/10.1098/rsif.2021.0058
Fabian et al (2018) Interception by two predatory fly species is explained by a proportional navigation feedback controller: https://royalsocietypublishing.org/doi/full/10.1098/rsif.2018.0466
Supple et al (2020) Binocular Encoding in the Damselfly Pre-motor Target Tracking System: https://doi.org/10.1016/j.cub.2019.12.031
Wardill & Fabian et al (2017) A Novel Interception Strategy in a Miniature Robber Fly with Extreme Visual Acuity: https://doi.org/10.1016/j.cub.2017.01.050
Gonzalez-Bellido et al (2016) Target detection in insects: optical, neural and behavioral optimizations: https://doi.org/10.1016/j.conb.2016.09.001

Further Info

Sam’s website: https://www.samueltfabian.com/
Damselflies of the UK entoLEARN course: https://courses.biologicalrecording.co.uk/courses/damselflies
Dragonflies of the UK entoLEARN course: https://courses.biologicalrecording.co.uk/courses/dragonflies

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