ABSTRACT Flower‐dwelling spiders are often regarded as antagonists in pollination systems because they prey on pollinators. However, their ecological roles may vary across development, particularly if immatures preferentially target floral exploiters rather than effective pollinators. We examined ontogenetic variation in flower use and prey composition among flower‐dwelling spiders. Field surveys conducted in 2023 and 2024 recorded 792 individuals, with Diaea subdola and Xysticus spp. being most abundant. Developmental differences in flower use were evident: small immatures (< 2 mm body length) predominantly occupied flowers of Lespedeza bicolor and Hosta sieboldiana, whereas larger immatures (≥ 2 mm) and adults more frequently used Patrinia scabiosifolia and Libanotis coreana . Thrips (Thysanoptera), generally considered floral exploiters, were overwhelmingly abundant on L. bicolor and H. sieboldiana , and prey records (dominated by D. subdola ) showed that small immatures primarily consumed thrips, larger immatures fed mainly on flies, and adults preyed predominantly on bees and wasps. These results suggest that small immatures may function as selective predators of floral exploiters, potentially reducing nectar and pollen loss and indirectly benefiting plants, whereas adults may exert antagonistic effects through predation on pollinators. Our findings demonstrate that the ecological impacts of flower‐dwelling spiders are strongly stage dependent, highlighting the importance of incorporating predator ontogeny when evaluating their roles in pollination networks.
Ishii et al. (Fri,) studied this question.