Study: Bugs aren’t bi­sex­ual, just in­com­pe­tent

Weekend Herald - - World - Sarah Knap­ton Group Ltd

It is a find­ing likely to send shock waves through the ad­mit­tedly nichein­ter­est world of in­sect sex­ual pol­i­tics.

Sci­en­tists have con­cluded that male in­sects that mate with other males 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. In some it is more com­mon than het­ero­sex­ual mat­ing.

The prac­tice has long puz­zled re­searchers be­cause it takes time and en­ergy, risks dis­ease and in­jury and of­fers no ge­netic ben­e­fits. It was spec­u­lated that it may show so­cial dom­i­nance, a prac­tice be­hav­iour, or sim­ply a sex­ual pref­er­ence.

But now sci­en­tists at the School of Bi­o­log­i­cal Sciences at the Univer­sity of East Anglia have con­cluded that bee­tles 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. Re­searchers con­cluded that, where there was much less pres­sure to find the right mate, the bee­tles sim­ply made more mis­takes.

By con­trast, when the pop­u­la­tion was male heavy, and there was an in­tense pres­sure on males to find the right mate, same-sex mat­ings were less fre­quent.

“In the male-bi­ased lines we found the male bee­tles were much more com­pet­i­tive at find­ing fe­males and mat­ing them ef­fi­ciently,” said Kris Sales, the lead re­searcher. “In the fe­male-bi­ased lines, it’s highly likely that a male mat­ing ran­domly will mate with a fe­male and pro­duce off­spring. In these lines it looks as though males have lost their abil­i­ties to dis­crim­i­nate be­tween male and fe­male mates.”

The team kept pop­u­la­tions of red flour bee­tles at dif­fer­ing sex ra­tios of 90 per cent male or fe­male. To check mat­ing mo­ti­va­tion, a male bee­tle from each pop­u­la­tions was given the choice of mat­ing with ei­ther a fe­male or a male, and their be­hav­iour was mon­i­tored.

Al­though the amount of sex­ual ac­tiv­ity was sim­i­lar in both groups, the re­searchers found that, in the pop­u­la­tion that was pre­dom­i­nantly male, the male bee­tles were much more se­lec­tive in their choice of mate.

They were more likely to mount the fe­male first and spend a longer amount of time with her. In the pop­u­la­tion that had more fe­males, the males were just as likely to mount a male as a fe­male and seemed to ran­domly choose the part­ner.

While the re­search shed light on an in­ter­est­ing in­sect world para­dox, re­searchers said the work did not re­veal much about same-sex be­hav­iour in hu­mans and other more com­plex an­i­mals.Tele­graph

It ap­pears the makeup of the pop­u­la­tion, and not pref­er­ence, in­flu­ences the sex­ual be­hav­iour of bee­tles.

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