Prey–predator interactions and body size relationships between annual cicadas and spiders in Japan

Abstract

ABSTRACT Cicada (Hemiptera) emergence is a major resource pulse that produces diverse effects on terrestrial food webs. Most studies have focused on periodical cicadas; however, little is known regarding the prey–predator interactions and size relationships between annual cicadas and predators, with knowledge being exclusively limited to the cicada–bird systems. Here, we focused on the interactions between annual cicadas and spiders in Japan. Based on direct observations and posts on social networking services and blogs on the Internet, we aimed to (1) reveal the major spider taxa as the predators of annual cicadas, (2) identify the major cicada taxa as the prey of spiders, and (3) characterise the prey–predator body size relationships between annual cicadas and spiders. Large orb-web spiders of the family Araneidae were identified as the major predators of annual cicadas. Spiders preyed on diverse cicada species, and prey species composition varied among the predator species. Regarding body size ratio, spiders tended to prey on cicadas larger than themselves (prey–predator body size ratio >1). We suggest that orb-weavers may function as one of the key predators of annual cicadas. Annual and periodical cicadas may be preyed upon by predators that use different foraging modes (web-builders or cursorial hunters). Further examination of these prey–predator interactions will contribute to the understanding of the cicada–predator systems.