Luo, Yun-Jia

Luo, Yun-Jia


Master student (Department of Life Sciences, National Chung-Hsing University, Taiwan)


Function of body color of Taiwanese crab spiders


Crab spiders are sit-and-wait predators which can change body colors depending on the color of flowers they sit on. Results of previous studies show that the body color of European crab spiders match that of the flowers, rendering them cryptic to pollinator prey. On the other hand, the body of white Australian crab spiders can reflect UV-light and behavioral studies demonstrate that spiders are attractive to bees. However, the potential functions of body color of Asian crab spiders are still not clear. In addition, recent researches reported that the bright body spots of some nocturnal orb web spiders were attractive to nocturnal prey. In this study, I investigate the functions of body color of Asian crab spiders, especially in the nocturnal context. Firstly I surveyed the temporal activity patterns of both Thomisus labefactus and Misumenops tricuspidatus crab spiders to realize the temporal hunting pattern of crab spiders. I found that both crab spiders mainly hunted at nigttime, and the number and biomass of their nocturnal prey were significantly higher than those of diurnal prey. Secondly, I measured reflectance spectra of white and yellow morph of the two spider species and white and yellow flowers they sitted, then calculated color contrasts to realize how these spider-flower combinations were viewed from potential diurnal and nocturnal prey. The results indicate that diurnal bee and nocturnal moth can discriminate spiders on flowers, no matter what color combination. Next, I will perform field experiments by placing white and yellow spider dummies on white or yellow flower petals, and use video cameras to monitor the response of prey to these dummies at day and night. Hopefully, results of this field experiment can determine whether body colors of Asian crab spiders function to conceal themselves or to attract prey under different light conditions.


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Updated: Nov-20-2020 02:10:19 (Taiwan, GMT+08:00).