Keywords :
Diet,
generalist,
orb web,
spider,
trophic niche
บทคัดย่อ :
Prey selection by generalist predators can be highly dynamic depending on the prey community
structure. However, the dynamics of prey selection at the stage of prey entrapping are rarely
investigated in trap-building predators, probably because their traps have been previously
considered to intercept mobile prey proportionally to its availability in environment. Here
we investigated the dynamics of prey selection by the orb-weaving spider Gasteracantha hasselti
(Araneidae) depending on the composition of the available prey in tropical lowland forests
located in north-eastern Thailand. We found that Gasteracantha captured a wide variety of
prey but selected, on average, mostly Coleoptera and Diptera. The selectivity of Gaster-
acantha s webs for Coleoptera was constant across the changes in overall prey availability
and prey composition. The web selectivity for Hemiptera decreased rapidly with increasing
relative densities of Hemiptera in the environment. The selectivity for Diptera and Hymen-
optera increased and decreased, respectively, with their absolute densities in the environment.
The relative selectivity of Gasteracantha s traps for a particular prey type was driven by the
presence and density of the highly selected prey rather than overall prey density. The results
show that the selectivity of Gasteracantha s traps for prey had both fixed and dynamic
components and the dynamic component was determined by the relative as well as absolute
densities of the particular prey types in the environment.
เอกสารอ้างอิง :
Michalko, R., Kosulic, O., Saksongmuang, V., Wongprom, P., Siripaiboon, P. and Trisurat, Y., 2020. The dynamics of prey selection by the trap-building predator Gasteracantha hasselti. Journal of Tropical Ecology, 36(3), pp.87-93.
