AV­ER­AGE JOES BEAT CASANOVAS

BBC Wildlife Magazine - - Wild News - SOURCE Royal So­ci­ety Open Science LINK http://bit.ly/2vzROxi

Males that con­trib­ute noth­ing more to re­pro­duc­tion than sperm are usu­ally best off putting all their ef­forts into mat­ing with as many fe­males as they can, as of­ten as pos­si­ble. There is such a thing as be­ing too en­thu­si­as­tic, though.

Male mosquitofish vary widely in terms of sex drive. “Se­lec­tion ought to oust males that dis­play low or av­er­age lev­els of sex­ual ac­tiv­ity,” says Carolin Som­mer-Trembo of Goethe Univer­sity Frank­furt. “We wanted to know how this vari­a­tion in male be­havioural types is main­tained.”

It comes down to fe­male choice. Fe­males ac­tively avoid the most highly sexed males. That’s partly be­cause such in­de­fati­ga­ble suit­ors leave fe­males with lit­tle time to feed. But also, their per­sis­tent at­tempts to cop­u­late of­ten in­flict gen­i­tal in­juries. Lit­tle sur­prise then that fe­males pre­fer to con­sort with males of a more ret­i­cent bent.

Ar­dent males do have their mo­ments. They are par­tic­u­larly at­trac­tive to in­ex­pe­ri­enced fe­males, for ex­am­ple, and to groups, when the male’s costly at­ten­tions can be shared among the school.

Male mosquitofish reach sex­ual ma­tu­rity as young as 43 days.

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