Anuran‐dependent predation by the giant water bug, Lethocerus deyrollei (Hemiptera: Belostomatidae), in rice fields of Japan

Abstract

We examined the seasonal dietary patterns of the endangered giant water bug, Lethocerus deyrollei, in rice fields located at Sayo, Hyogo Prefecture, central Japan. The results showed that L. deyrollei underwent a shift in its major food item from breeding adults of Hyla japonica in spring (May and June) to newly metamorphosed juveniles of Rana nigromaculata in summer (July to September). Dietary shifts were shown to correspond with a seasonal fluctuation in the availability of anurans in the rice fields. Although adults of R. nigromaculata were relatively abundant throughout the active season they were infrequently exploited by L. deyrollei, possibly because of the difficulty in handling these large‐sized frogs. Therefore, seasonal partitioning of the rice‐field habitat by small‐sized frogs, adult H. japonica and juvenile R. nigromaculata, would enable L. deyrollei to forage in the rice fields during the extensive active period. From these results, we suggest that the conservation of frog populations is very important for the preservation of this endangered insect and for the maintenance of biodiversity within these rice‐field ecosystems.

Notes on predators and their effect on the survivorship of the endangered giant water bug, Kirkaldyia (= Lethocerus) deyrolli (Heteroptera, Belostomatidae), in Japanese rice fields

“…The rice field habitat may become overcrowded with newly emerged adult K. deyrolli because of its almost synchronous emergence in summer (Hirai & Hidaka 2002). New adults may cannibalize fifth instar nymphs with delayed emergence.…”

“…Contributing factors such as decreased suitable aquatic habitats and food resources, as well as water pollution, especially pesticide application, were investigated and verified in some studies (e.g. Ono, 1995;Hirai & Hidaka, 2002;Ohba & Takagi, 2005).…”

“…The giant water bug, Kirkaldyia deyrolli Vuillefroy, is distributed in Japan from central Honshu to the Ryukyu Islands. Rice fields are an important habitat for K. deyrolli (Hashizume, 1994;Hirai & Hidaka, 2002;Mukai et al, 2005). Japanese populations of K. deyrolli decreased sharply during last four decades and are considered as threatened-vulnerable species in the Red Data Book of Japan (Japan Environment Agency, 2000).…”

Ground arthropod communities in paddy fields during the dry period: Comparison between different farming methods

“…Despite this dominance, studies of organisms in these fields have been almost exclusively conducted in the flooded portion during the cultivation period to substitute for wetland habitats (Moriyama, 1997;Hidaka, 1998;Natuhara, 2013, but see Bambaradeniya et al, 2004;Stenert et al, 2009). Flooded fields are used as breeding and feeding habitats by fish (Saitoh et al, 1988;Nagayama et al, 2012), waterbirds (Lane and Fujioka, 1998;Toral et al, 2011), amphibians (Fujioka and Lane, 1997;Matsuhashi and Okuyama, 2002), aquatic insects (Hirai and Hidaka, 2002;Nishihara et al, 2006;Watanabe et al, 2013), and aquatic micro-organisms (Yamazaki et al, 2004a(Yamazaki et al, , 2004b. Other studies have focused on pest and/or predator populations in rice plants (Kajimura et al, 1993;Murata, 1995;Motobayashi et al, 2006).…”

Habitat utilization by the giant water bug, Appasus (=Diplonychus) major (Hemiptera: Belostomatidae), in a traditional rice paddy water system in northern Osaka, central Japan

“…Topics such as the life cycle of Sympetrum dragonflies (Ueda, 1998), food preferences of nepids and belostomatids (Okada and Nakasuji, 1993a;Hirai and Hidaka, 2002;Ohba and Nakasuji, 2006), the interspecific relationship between two closely related belostomatine water bugs (Okada et al, 1992), and the factors affecting the induction of flight behavior in a lethocerine water bug (Ohba and Takagi, 2005) have been studied thus far with respect to lentic insects. Studies on seasonal habitat utilization by several aquatic insects in rice paddy water systems have also been conducted, and some authors have pointed out that a habitat mosaic in and around the water system would be necessary for aquatic insects to thrive (Hibi, 1994;Ueda, 1998;Saijo, 2001).…”