London, Jan 31 (ANI): A new study has found that female spiders are at the mercy of certain parasitic bugs that kills of their embryonic sons.
Wolbachia bacteria are transmitted through eggs, so their survival depends on how many females are born.
This evolution strategy allows the bacteria to maximise their chances of making it to the next generation.
The parasite can drive their hosts to virgin births, resulting in the spiders giving birth only to females, or males that turn into females. If neither works, they simply kill the males off.
Bram Vanthournout at Ghent University in Belgium and colleagues have found that infected female dwarf spiders produce more females than those without Wolbachia.
However, giving the spiders antibiotics restored a normal sex ratio.
"Some social spiders need very few males, so male competition is high," New Scientist quoted Vanthournout as saying.
Wolbachia might spare females the trouble of producing males who will never mate.
The study appears in BMC Evolutionary Biology. (ANI)