Interspecific encounters between male aeschnids do they have a function?


Male aeshnid dragonflies at a small pond (circumference ca 90 m) in Cambridgeshire U.K. generally pursued males of other aeshnid species as well as their own. As a result of these encounters the pursued insect frequently left the pond, particularly when it belonged to a smaller species. Libellulids, which differed greatly from the aeshnids in size and appearance, were also pursued. Male aeshnids attacking males of other species frequently pressed home their attacks even when they were close enough apparently to identify the pursued insect. Consequently interspecific pursuits appear to have a function over and above ensuring that no opportunity is lost to mate or to drive out a conspecific rival. It is suggested that a positive function of interspecific pursuit is practice in developlng fighting skills against conspecifics.

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