It is a finding likely to send shockwaves through the diminutive world of insect sexual politics. Scientists have concluded that male insects which mate with other male insects are not gay, or even bisexual. They are just hugely incompetent.

More than 100 species of insects engage in some kind of same-sex mating, and in some species it is more common than heterosexual mating.

But the practice has long puzzled researchers because it takes time and energy, risks disease and injury and offers no benefits in passing down genes to future generations.

For that reason it was speculated that it may a way of showing social dominance over male rivals, a practice behaviour, or even simply a sexual preference.

But now scientists at School of Biological Sciences the University of East Anglia have concluded that, in the case of beetles at least, the insects are simply inept.

In the study, published in the journal Animal Behaviour, results showed that within populations of mostly female beetles, the males were much more likely to copulate with other males.