Shocking details here. (“’Paranoia’ About Rivals Alters Insect Mating Behavior,” ScienceDaily, August 16, 2011):
Females in many species of animal have multiple mates and males have evolved particular reproductive characteristics to ensure their sperm are successful when in competition with the sperm of other males. Adaptations include physical traits that result in increased sperm count, as well as behavioural alterations such as mating with females for up to 21% longer than they normally would.
In types of fruitfly where the female only mates once, however, there is little need for competitive behaviour. The male is not expected to increase its reproductive efforts in response to competition, because it ‘knows’ that the female will be fertilised with its sperm only. Scientists at Liverpool, however, have found that once a male had been in contact with another male, it subsequently increased the length of time it mates with a female by 93%, even though the risk of the female being fertilised by another male was remote
The researchers then go to considerable trouble to come up with a pure Darwinist “selfish gene” explanation, which tends to make them sound ridiculous (which is too bad):
There doesn’t appear to be an immediate biological reason as to why they would do this, but it is perhaps to ensure that the female remains fertile with one male’s sperm for her lifespan, even though the chance of reproducing with another is remote
How about a lone male nearby reminds the fly that life is uncertain. Pleasures can just take flight. So he hangs on to what he’s got? Darwinism inserts artificial explanations, aimed only at demonstrating Darwinism, when actual explanations would be simpler.