Call it the insect version of foreplay. Like humans, tangle-web spiders (Anelosimus studiosus) engage in playful sexual behaviors that include courting and mock copulation, usually before the females are mature enough to mate. Researchers have found that the activity keeps females happy; they're more likely to mate and less likely to attack males when they're finally ready for sex. But foreplay may come with a cost for males. As the team reports online this month in Ethology, males that invest a lot of effort in fooling around with females may end up exhausted and thus less competitive when they need to fight rivals for a mate. So, at least for male spiders, foreplay doesn't always pay off.
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