Chat up strategies in the insect and spider world

Compiled by Val N Tynsdie


"Come on baby light my fire"

Male fire flies of the family Lampyridae send out flashes of light in a species specific sequence. The receptive females answer with a matching pattern of usually brighter flashes. Once the male fire fly has found a potential partner, he touches her with his antennae to check that she has the correct scent.
 
 

"If music be the food of love"

Some species of spider have "stridulatory organs" which make a rasping sound when rubbed together. When the male wolf spider stridulates, he sends the vibrations through a leaf to the chosen female. As the female picks up the vibrations via sensory hairs in her legs she becomes sexually receptive. This musical turn on is essential if the male is to escape being eaten while he attempts to mate.

Crickets rub their wings together to play a romantic tune. Veins in the wings have tiny teeth which scrape across the opposite wing and so produce a characteristic song. The male's song informs the female that the male has produced a spermatophore (a small packet of sperm) and is ready to mate. The sounds are detected by special organs situated in the front legs.

Grasshoppers produce their serenades by rubbing the serrated edge of their hind legs against their folded wings.
 
 

A variation on the flower and chocolate theme and "I love you so much I could eat you"

Often male spiders are much smaller than the females and risk being eaten every time they make a romantic overture. The male hunting spider Pisaura listeri attempts to overcome this threat by offering his mate a gift of a dead fly decoratively wrapped in silk, spun by himself. If he is lucky the female accepts this gift and allows him to mate with her. The worse case scenario is that she accepts the gift and then eats him before he can get in on the act.

The male dancing fly threatened by the possibilty of being his chosen female's next meal offers a diversionary tidbit which the female can eat during mating. Less lucky are the males of the biting midge family (Ceratopogonidae), the female sucks out the contents of the male's body while he is in the process of mating.

The male burying beetle Nicrophorsis defodiens finds a suitable dead animal (such as a mouse) and release pheromones onto it to attract a female. Once they have mated, the two beetles bury the carcase and the female lays her eggs close to it.
 
 

And now for something completely different

The female bed bug Cimex lectulaius has no vagina, so, during the mating process the male drills his own through the female's body wall before delivering his spermatophore. This process goes by the descriptive term traumatic fecundation. Once inside the female's body, the sperm swim about in the female's blood and finally make their way to the ovaries and wait for the release of eggs.

The male wheel web spider expends so much energy in mating, that after fertilisation he drops off and drops dead. Not wishing to waste a good meal, the female then promptly eats him.

The females of many insect species can reproduce without any male intervention. This method of reproduction is called parthenogenesis. In the summer months, many generations of aphids are produced without males. While in honey bees, unfertilised eggs hatch into males and fertilised eggs into females.


Comments on the article to the author Anne Bruce.


 

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