The water system of traditional rice paddies as an important habitatof the giant water bug, Lethocerus deyrollei (Heteroptera: Belostomatidae)

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

“…3 and 5). In the other belostomatid lethocerine, Lethocerus deyrolli, high prey density, high water temperature and available oviposition substrata were considered as important factors affecting the density in different types of waters in the paddy system (Mukai et al, 2005). This study showed that prey density was also among the important factors affecting the density of A. major.…”

“…This study showed that prey density was also among the important factors affecting the density of A. major. The density of A. major was high in waters where aquatic insects such as nymphs of libellulids, and adults and nymphs of corixids were abundant, while the density of L. deyrolli was affected by that of tadpoles and frogs (Mukai et al, 2005). Okada and Nakasuji (1993a) reported that libellulid larvae are among the possible prey of A. major in the rice paddy water systems in Okayama Prefecture, western Japan.…”

“…Indeed, A. major was found reproducing in all types of waters including the Marsh, where the water temperature was always lower than in other waters at the study site in the reproductive season in A. major. Mukai et al (2005) pointed out that L. deyrolli do not utilize the Marsh for reproduction, probably because of the low water temperature, low density of possible prey and absence of suitable oviposition substrata. Females of L. deyrolli lay eggs on substrata such as culms of aquatic plants, while belostomatine bugs such as A. major, whose females lay eggs on the back of male adults, need no substrata for oviposition.…”

“…The environment and vegetation structure in and around the waters, and agricultural regimes, such as water management performed in and around the site, were described in detail in Mukai et al (2005).…”

Freshwater biodiversity in human-dominated landscapes: introduction

“…Specifically, humandominated landscapes in rural areas, also known as Satoyama, are characterized by a long history of human intervention with farmland, farm ponds, streams/ditches, grassland and secondary forests around villages (Katoh et al 2009). Many organisms in Satoyama exhibit life history adaptations to moderate anthropogenic disturbances (e.g., Mukai et al 2005). Therefore, traditional farming and forestry activities are keys to maintaining the biodiversity of Satoyama.…”