From The National Geographic:
Disguises used by female damselflies to avoid unwanted sexual advances can cause males to seek out their own sex, a new study suggests. Belgian researchers investigated why male damselflies often try to mate with each other. The scientists say the reason could lie with females that adopt a range of appearances to throw potential mates off their scent. In an evolutionary battle of the sexes, males become attracted to a range of different looks, with some actually preferring a more masculine appearance.