Picky male spiders avoid unwelcome dinner date

It's not easy being a male spider. Would-be fathers from the widow spider genus have had to develop a tactic to survive a common fate of death after copulation.

Rather than mate with adult females, the male spiders pair instead with younger females that have not quite matured.

Both adult and younger females have developed sexual cannibalistic behavior. But when the younger females molt for the last time, the threat of their eating their male partners is lower.

A team of scientists, led by zoologist Maydianne Andrade from Canada's University of Toronto Scarbrough, have found that within two species males will often mate with females before they shed their skin for the final time.

The study is published on Wednesday in the journal "Biology Letters."

Make your move, spider!

It's just a small window of opportunity. But the strategy works to their evolutionary advantage as the females store the sperm and fertilize their eggs when they are fully grown.

And, the male spiders don't get eaten.

There are about 30 types of widow spider, including the formidably venomous black widow. However, the behavior found by Andrade's team was observed only in redback spiders (main picture) and brown widows.

A spider's wedding gift

The tactic is just one of many that male spiders adopt to escape becoming an early lunch, or at least to ensure reproductive success.

A male nursery web spider will present his female with a "nuptial gift" of food, which helps ensure his mating success and protects him from being eaten before he can deposit his sperm.

While the arachnid might appear chivalrous in spirit, he's also likely to hold on to the food with his leg - feigning death at the same time - to stop the female running away with it.

Soren Toft and Maria Albo, from Denmark's Aarhus University speculate that the nuptial gift "trait" has evolved partly to counter female aggression.

'Coy males, seductive females'

In most species, the female, rather than the male, tends to be the choosy one. She's left holding the baby - or at least investing more in her offspring - so it pays to be picky and seek out the best genes.

Tropical tent web spider males, though, get to be the more pernickety partner, as shown by a team from the Ben-Gurion University of the Negev in their study, playfully titled, "Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola."

Even if tropical tent webs can avoid being eaten, mating means they will stop building webs, stop eating, and die.

As a result, the male tends to place a great weight on his decision, favoring young and well-fed females that are likely to have more offspring.