Damselflies belong to the same order (Odonata) as dragonflies. After a pair of damselflies have successfully mated, the males (which are balancing on top of the females in the image) will often remain with the female to guard her while she lays eggs. When males exhibit this behavior it is either because they are protecting the female from predators (he went through a lot to get her interested and get her to mate) or because they practice ‘sperm competition.’ Sperm competition is literally competition between males to inseminate a female and for that female to use their sperm to fertilize her eggs. In many damselfly species the males are capable of removing sperm from inside the female’s reproductive tract – this means that one male can inseminate a female, but if he doesn’t remain with her while she is laying her eggs another male could come along and remove the sperm deposited by the first male – essentially undoing his insemination and thus any paternity to future offspring. With many damselfly species it is not uncommon to see large groups of these females with males balancing on top of them in the same area – occasionally they even perch on top of each other!
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