01918nas a2200145 4500008004100000245008200041210006900123300001200192490000700204520145100211100001401662700001501676700001901691856006201710 2016 eng d00aCrab spiders (Thomisidae) attract insect flower-visitors without UV signaling0 aCrab spiders Thomisidae attract insect flowervisitors without UV a611-6170 v413 a
1. Crab spiders (Thomisidae) indirectly affect insect flower-visitor and flowering plant interactions by consuming and altering the behaviour of insects. 2. Although one expects insect flower-visitors to avoid crab spiders actively, some crab spider species are known to attract flower-visitors. Crab spiders may use UV signalling to lure potential prey to the flowers they occupy. 3. In the present study, a field experiment was conducted to examine the effects of crab spiders occupying three prairie plant species for the insect flower-visitor community. Pollinating insects were significantly attracted to inflorescences with crab spiders compared to inflorescences without crab spiders for two plant species, and herbivorous insects were attracted to inflorescences with crab spiders for one of these plant species. The two flowering plant species with increased pollinator visitation showed increased seed weights for plants with crab spiders, indicating crab spider presence indirectly increased pollination. 4. To test the UV signalling hypothesis, inflorescences with crab spiders of one plant species were observed under both a UV-blocking plastic and a clear plastic control. Contrary to our prediction, flower-visitors were not more likely to land on inflorescences under the clear plastic; the UV signalling hypothesis was not supported. Other unknown explanations underlie prey attraction to inflorescences with crab spiders.
1 aWelti, E.1 aPutnam, S.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/een.12334