Male flies produce a chemical that makes females sleep in after mating

A “sex peptide” transferred from male to feminine fruit flies throughout mating interferes with the feminine’s organic clock, lowering her possibilities of mating once more

By Christa Lesté-Lasserre

During intercourse, male fruit flies switch a chemical that makes females sleep later, lacking the prospect to mate with different males.

This “sex peptide”, which will get handed together with sperm by the male’s intercourse organ into the feminine’s physique, is already identified to make females much less receptive to different males. But a brand new examine reveals that it additionally interferes with the organic clock mechanism that normally wakes up fruit flies earlier than dawn, which is when mating usually happens, says Lorena Franco on the National Scientific and Technical Research Council (CONICET) in Argentina.

“The loss of anticipation [of the dawn] could further reduce receptivity by putting females to sleep when males are most active,” she says.

Previous research have discovered that fruit flies (Drosophila melanogaster) usually get up an hour or two earlier than the solar rises or the lights in a laboratory are switched on. But Franco and her colleagues realised that these research had been targeted on male flies.

Because females are sometimes missed in fruit fly analysis generally, they determined to make use of webcams to observe the exercise of virgin and just-mated feminine fruit flies of their light-controlled laboratory for 4 days. They additionally studied a bunch of males for comparability.

To their shock, the researchers discovered that the one females that might nonetheless anticipate the morning had been the virgins, whereas the mated females continued to sleep till they awoke with a startle on the first mild of day. “In mated females, this [morning anticipation] feature is completely suppressed,” says Sebastian Risau Gusman, additionally at CONICET.

The researchers suspected that the intercourse peptide could be concerned, so that they silenced sure teams of neurons with intercourse peptide receptors in mated females’ reproductive tracts. Those females recovered the flexibility to get up earlier than daybreak, says Franco.

Fluorescent tracers had been then used to trace the consequences of the peptide on the females’ nervous techniques. This revealed that the intercourse peptide seems to set off a series of occasions from the reproductive system to the mind, affecting constructions that management the bugs’ inner clock.

Female flies can mate with many males and retailer their sperm inside their our bodies. Producing behaviour-altering chemical substances is a approach for males to enhance the possibilities of their sperm being profitable. “This is a ‘strategy’ of the male to keep other sperm from competing with his own inside the female,” says Risau Gusman.

Journal reference: PLOS Genetics, DOI: 10.1371/journal.pgen.1010258