Flying insects take note of opponents' strengths and abilities before entering into a fight

March 25, 2015
Damselfly war games

Before a male damselfly hot-headedly enters into a duel of aerial sparring, it first works out its strategy. It gives its opponent's wings a once-over to assess its strength, knowing that more transparent wings and larger red spots generally show a stronger rival. Those who then decide to engage in long fights either try to wear their opponent down, or dazzle them with brilliant aerial moves that are too hard to follow. These damselfly war game strategies are set out in a study published in Springer's journal The Science of Nature - Naturwissenschaften. Two research groups united forces to arrive at these findings, one based in Brazil, led by Rhainer Guillermo-Ferreira, and the other in Germany, led by Stanislav Gorb.

Male Mnesarete pudica damselflies, like many other winged insects, engage in energy-consuming aerial stand-offs to secure the best mates and territory. To find out how these insects decide whether or not to take up a challenger, Guillermo-Ferreira and his colleagues conducted fieldwork at a stream in Sao Paulo State in Brazil. Among other things, they filmed territorial fights and experimentally manipulated the wing pigmentation of some males.

The researchers realized that strong male damselflies probably adopt various decision-making strategies and steps before and while they take on a challenger of different strengths. To assess whether an opponent is weak or not, they first take wing pigmentation into account. Males with more transparent wings and bigger red spots are usually stronger.

Strong males tend to solve conflicts against weaker opponents through less energy-taxing, but much more aggressive, tactics such as chasing, grabbing, and biting. Because weaker males have less energy to fight, they only engage in brief pursuits without making too much effort during aerial displays.

When two strong opponents take each other on they will limit their chances of injury by choosing to go head-to-head in non-contact aerial display fights that are longer and more intense. In such cases males generally use two strategies. Through the so-called war-of-attrition strategy they physically try to wear their opponents down through repeated attacks. Threat displays, which are typical of longer fights, are then used until one of the contestants reaches his physical limits and withdraws.

The video will load shortly.
Male damselflies (Mnesarete pudica) in an aerial contest. Credit: Stanislav Gorb

The strong males could also follow a sequential assessment model in which they regularly take a step back mid-fight to assess the situation to decide whether it's worth their while to continue or not. In such cases, aerial displays of increasing difficulty are performed until the first damselfly is not able to perform a routine and gives up.

"Even animals with simple nervous systems, such as damselflies and other insects, may exhibit complex assessment strategies," says Guillermo-Ferreira.

Explore further: Study on insect aggression and neurochemistry

More information: Guillermo-Ferreira, R.; Gorb, S.N; Appel, E.; Kovalev, A.; Bispo, P.C. (2015). Variable assessment of wing colouration in aerial contests of the red-winged damselfly Mnesarete pudica (Zygoptera, Calopterygidae), The Science of NatureNaturwissenschaften. DOI: 10.1007/s00114-015-1261-z

Related Stories

Study on insect aggression and neurochemistry

January 27, 2015

College of Liberal Arts and Sciences Professor and Chair of Biology John Swallow and his lab groups are applying information about neurotransmitters to illustrate the power of using insect models to study aggression. Swallow ...

Female cowbirds prefer less intense male courtship displays

May 3, 2012

In most species, females prefer the most intense courtship display males can muster, but a new study finds that female cowbirds actually prefer less intense displays. The full results are published May 2 in the open access ...

Female mice do not avoid mating with unhealthy males

March 13, 2015

Female mice are attracted more strongly to the odour of healthy males than unhealthy males. This had already been shown in an earlier study by researchers from the Konrad Lorenz Institute of Ethology at the Vetmeduni Vienna. ...

Recommended for you

These shrews have heads that shrink with the season

October 23, 2017

If any part of the body would seem ill equipped to shrink, it would probably be the head and skull. And, yet, researchers reporting in Current Biology on October 23 have found that the skulls of red-toothed shrews do shrink ...

Single-molecule dissection of developmental gene control

October 23, 2017

Scientists at EPFL and Max Plank have made significant discoveries on how developmental genes are controlled by the methyltransferase enzyme PRC2. The study is published in Nature Structural & Molecular Biology.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.