A bizarre form of inbreeding could spell the end of males in one insect species, according to researchers from Oxford University. The research focused on cottony cushion scales, a hermaphroditic bug species in which females appear to fertilize their own eggs.
"It turns out that females are not really fertilizing their eggs themselves, but instead are having this done by a parasitic tissue that infects them at birth," said Laura Ross, one of the study's authors. "It seems that this infectious tissue derives from leftover sperm from their fathers."
In effect, the tissue enables males to father offspring with both their mates and then their daughters. According to a mathematical model developed by Ross and her co-author Andy Gardner, this odd reproductive tactic could eliminate the need for males in the species. Once the parasitic fathers become widespread in a population, females will be inclined to reproduce with them instead of regular males. Regular males, as a result, become very rare because they have a hard time finding willing mates.
The research appears in the American Naturalist.
- Andy Gardner, Laura Ross. The Evolution of Hermaphroditism by an Infectious Male-Derived Cell Lineage: An Inclusive-Fitness Analysis. The American Naturalist, 2011; 178 (2): 191 DOI: 10.1086/660823
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