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

Abstract

A field research was carried out in Hyogo Prefecture, Japan in order to establish the role of the water-scorpion, Laccotrephes japonensis Scott as predator of nymphs of the endangered giant water bug, Kirkaldyia (= Lethocerus) deyrolli. To assess the impact of this predator, a field experiment was set up with (Control) and without L. japonensis (Removed). The survival rate of K. deyrolli in Removed treatment was higher than in the Control. Our experimental results showed that L. japonensis is an important predator for K. deyrolli nymphs in the field.

Taxonomic review and distribution of giant water bugs (Hemiptera: Belostomatidae: Lethocerinae) in the Palearctic, Oriental, and Australian regions

“…Indeed, the results of the present study confirm that the genetic distances between K. deyrolli and Lethocerus species (i.e., 16.8% with L. indicus, 16.5% with L. insulanus, and 16.4% with L. patruelis; average = 16.5%) lay within the range of intergeneric distances reported between the genera of other hemipteran groups (i.e., 14.9-19.9%: Park et al 2011;Jung et al 2011a;Tembe et al 2014;Kaur & Sharma 2017). Therefore, the various synonyms of K. deyrolli (e.g., L. deyrolli, L. deyrollei, and K. deyrolli: Ichikawa 1995;Polhemus 1995;Ohba 2007;Ho et al 2009;Yoon et al 2010) should no longer be used, and K. deyrolli should be accepted as the valid name for the species.…”

“…; Kaur & Sharma ). Therefore, the various synonyms of K. deyrolli (e.g., L. deyrolli , L. deyrollei , and K. deyrolli : Ichikawa ; Polhemus ; Ohba ; Ho et al . ; Yoon et al .…”

Ecology of giant water bugs (Hemiptera: Heteroptera: Belostomatidae)

“…The proportion of cannibalism in A. japonicus and Appasus major Esaki was found to be higher than in K. deyrolli , as estimated by analyzing dietary items, indicating the dietary difference between the species of Belostomatinae (invertebrate eaters) and Lethocerinae (vertebrate eaters) (Okada & Nakasuji ; Ohba & Nakasuji ). Nymphs of K. deyrolli were eaten by other aquatic insects (mainly Laccotrephes japonensis Scott) and conspecifics (Ohba ; Ohba & Nakasuji ; Ohba & Swart ). Predation of L. japonensis on K. deyrolli nymphs was weaker when tadpole (common prey of L. japonensis adults and K. deyrolli nymphs) prey abundance was high (Ohba & Nakasuji ; Ohba ).…”

Intraguild predation of water scorpion Laccotrephes japonensis (Nepidae: Heteroptera)

“…The younger nymphs of the giant water bug Kirkaldyia (= Lethocerus) deyrolli Vuillefroy (Belostomatidae) are considered to be predators that prey mainly upon tadpoles (Ohba and Nakasuji 2006;Ohba et al 2008). In addition, the water scorpion Laccotrephes japonensis Scott adult (Nepidae) prey upon K. deyrolli younger nymph (Ohba 2007) and tadpole in rice younger nymph of K. deyrolli, and anuran larva (tadpole) are regarded as intraguild predator, intraguild prey, and common prey, respectively (Ohba and Nakasuji 2007). Commonly sympatric in Japanese wetlands adult L. japonensis and younger nymph of K. deyrolli meet the definition of same guild members, competing with each other for tadpoles and other aquatic invertebrates with younger nymphs of K. deyrolli serving as intraguild prey for L. japonensis.…”