Researchers at University of Regensburg and IST Austria found that male Cardiocondyla obscurior ants constantly patrol the nests to ensure that they are able to bite or chemically tag a rival as soon as he is born. Chemically tagged ants are then quickly destroyed by workers.
When ants emerge from their pupae, or eclosion, they are vulnerable to attack because their exoskeleton has not yet hardened to protect them and their mandibles are also too weak to bite an attacker.
And a rival is easy to spot because male Cardiocondyla obscurior ants are diphenic, either winged or wingless. The dominant wingless male ant, therefore, keeps an eye out for newborn winged ants.
The researchers investigated the behaviour of male ergatoid C-obscurior ants in response to newly pupated males and females, as well as their interaction with developing pupae.
Lead study author Dr Sylvia Cremer from IST Austria said: "Older ergatoid male ants are able to distinguish pupae containing females by their chemical scent from those containing males.
"Pupae containing males are often bitten while those containing females, or winged males disguised as females, elicit a mating response.
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"However, the chances of mistakenly killing a female or worker possibly prevents older males from attempting to completely destroy all rival males before they emerge from their pupae."
It would be advantageous for newly emerged males to hide from attackers. However, while winged males use chemical female mimicry to avoid being detected, young wingless males are easily detected and attacked by older males, the researchers said.
If the fight occurs during the first day after eclosion the older male will always win, but once the younger male's exoskeleton hardens his chances of surviving rises to 14 per cent, they noted in a paper published in journal BMC Ecology. (More)