Greifswald (Germany) – Scientists said on Tuesday that they have for the first time found evidence of nerve cells in the sex organ of male spiders.
Zoologists from the University of Greifswald in Germany, reported in the journal “Biology Letters’’, that the discovery has overturned the previous theories that the organ was effectively numb in all spider species.
Elisabeth Lipke, Leader of the team, said the recent discovery showed that the males apparently have some influence over their mating success, and not just the females as previously assumed.
She said the males receive information on the female during copulation and are apparently able to influence the flow of their ejaculate accordingly.
Lipke said they analysed the Tasmanian cave spider male organ, using transmission electron microscopy to magnifications of 15,000 to 20,000.
Tasmanian cave spider (Hickmania troglodytes), was an Australian species the size of the palm of a hand.
“The neurons at the tip of the copulatory organ control pressure and flow, and could help the male to adjust better to the female during mating.’’
Lipke said they the scientists also noted two glands in the sex organ that apparently play an important role in the transfer of sperm during copulation.
“Spider males are able via these glands to modify the composition of their seminal fluid and emit additional secretions to the female, thus influencing processes in the female.
“In this way the males can secure paternity through the addition of individual secretions,’’ she said.
Peter Michalik, co-author of the study and an expert on the evolutionary morphology of spiders, said the females frequently mate with several males, which strive to impress their chosen mate with presents.
He said it was assumed that when copulation lasts longer, more sperm was transferred and thus more offspring was produced.
“To date the male has been ascribed a merely passive role.
“Male Tasmanian cave spiders apparently have a direct influence on copulation,” he said.
While the Greifswald scientists have demonstrated the existence of the nerve tissue, their precise function has yet to be analysed in experimental studies.
According to the team, whether or not the males actually enjoy having sex remains an open question.
They said there would be future studies to determine whether there are similar nerve cells in the copulatory organs of other spider species. (dpa/NAN)