‘Paranoid’ insects double mating time with females

August 9th, 2011 - 6:07 pm ICT by IANS  

London, Aug 9 (IANS) Male insects which become ‘paranoid’ in a rival’s presence, double the mating time with a female even though her risk of being fertilised by another male is remote.

A competitor’s presence triggers the ‘fear’ that a male is not likely to obtain another female, and so it does everything to keep the one female fertile with its sperm for its entire lifespan.

Adaptations include increasing sperm counts, as well as mating with females longer than their normal durations, the journal Biology Letters reports.

Anne Lize, biologist at the University of Liverpool, who led the study, says: “We already knew, from previous studies, that male insects evolve physical and behavioural characteristics to make them a stronger reproductive competitor for females that mate with many males.”

In fruitfly where the female only mates once, the male can ignore competitive behaviour, because it ‘knows’ that the female will be fertilised with its sperm only, according to a Liverpool statement.

Researchers, 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 percent, or almost double the time.

Some butterflies, for example, have evolved disproportionately large testes so that males can deliver increased sperm numbers.

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