Testing the prey attraction function of stabilimenta in orb-webs of Argiope luzona and Argiope aemula (Araneae: Araneidae).

Y-maze choice experiment were used to examine the prey-attraction hypothesis for the function of stabilimentum on the orb-webs of Argiope aemula and A. luzona. Fruit flies (Drosophila spp.), common prey species for spiders were used to determine whether webs with stabilimenta attract more flies in Y-maze choice experiment. The result showed that under well-lit condition (bright light), webs with stabilimenta significantly attracted more prey compared to those without stabilimenta in A. aemula and A. luzona. However, regarding the prey capture rate in bright light, only A. aemula showed an increased in the number of prey captured in decorated webs. Under dim condition, the results still showed a significant difference in the number of approaching prey, but not in the number of prey captured by the webs. In both species, the number of prey approached and intercepted in the decorated webs were higher in well-lit condition than in dim condition, suggesting that fruit flies are attracted to webs with stabilimenta in both species studied. Our data is congruent with the prey-attraction hypothesis as function of stabilimentum. [ABSTRACT FROM AUTHOR]