Harpactea sadistica spider sex is violent but effective
Spider sex has been found to be violent, but incredibly effective, according to a group of scientists who are studying them in Israel.
The Harpactea sadistica species male pierces the female's abdomen and therefore can fertilise their eggs directly in their ovaries. This traumatic event allows the first male that comes across the female a chance to inseminate the eggs as he can essentially shoot his sperm directly into where the ovaries are located.
This process has never been seen before in spiders, but a similar process has been spotted in mites and bedbugs.
Usually male spiders deposit their sperm into a small web that is then inserted into a receptacle between the ovipore and ovary using a pair of appendages and is then held there until an egg is released that can be fertilised.
The spermatheca spider uses the 'last in, first out' approach so that if any other males come along after the first one, the last one to have sex with the female is first in line to fertilise her eggs.
However, the Harpactea sadistica, bypasses this as the male's sperm can bypass all the other organs and go directly to the ovaries. The male has specalised sex organs, one part for gripping and the other like a hypodermic needle, used for injecting sperm.
Like many spider mating rituals, H. sadistica 's approach follows an elaborate pattern, with the male tapping the female, subduing her, and wrapping himself around her to properly position the sex organs.
He then alternates between the two, piercing and injecting the sperm on one side, then the other, forming two neat rows of holes in her abdomen.
As a result, the female of the spermathecae are shrinking into non-existence, as the more direct males approach is breeding out the other spiders.
"In insects there is a co-evolutionary development of female physiological responses to the male sperm that gives her at least some control of fertilisation," said William Eberhard, an expert in the mating habits of insects and spiders at the Smithsonian Tropical Research Institute.
"Something similar might occur here."
As this process develops, the female spider may evolve to have a secondary genitalia nearer to the ovaries, to avoid potental injury. This would be similar to some other spiders and butterflies.