Nuptial gifts of male spiders function as sensory traps.
While nuptial food gifts come in various forms in arthropods, their evolutionary origins are unclear. A previous study on insects has shown that such gifts may arise as a sensory trap that exploits a female's underlying motivation to feed. Here I present independent evidence of a sensory trap in spiders. In certain visually oriented spiders, I suggest that males initially exploit the maternal care instinct by producing a nuptial gift that closely resembles the female egg sac. Males of the spider Pisaura mirabilis cover their prey gift with a silk layer, transforming it into a white round object. In a laboratory experiment I tested whether the colour of the gift affected the rate that females accepted males displaying their gifts. I found that the brighter and the more alike the nuptial gift to a female's egg sac, the faster the female responded by grabbing the gift. My results support the hypothesis that the nuptial gift in P. mirabilis works as a sensory trap.
Stålhandske
Pia
P
Animal Ecology, Department of Zoology, Göteborg University, Box 463, SE-405 30 Göteborg, Sweden. pia.stalhandske@zool.gu.se
D000818:Animals; D005260:Female; D008297:Male; D012726:Sexual Behavior, Animal; D013112:Spiders