A comparison of predacious aquatic insect fauna and density in ground pools and concrete pools created during the Great East Japan Earthquake in 2011

Abstract

The tsunami caused by the Great East Japan Earthquake on March 11, 2011 hit the Pacific coast and caused heavy destruction of natural and man-made environments in northeastern Japan. This study focuses on mosquito larvae and their potential aquatic insect predators associated with ground pools and pools that appeared in the concrete foundations of destroyed houses (concrete pool) in inundated areas in Miyagi Prefecture, Japan. Field samplings were conducted on late July 2013. Culex inatomii, Cx. pipiens group, Cx. tritaeniorhynchus, and Cx. orientalis were collected from ground pools and concrete pools. The abundance of Cx. inatomii and Cx. pipiens groups in concrete pools was significantly greater than that in the ground pools. A large number of Hydroglyphus japonicus were collected as potential mosquito predators, followed by Micronecta spp., Enochrus japonicus, Rhantus sturalis, Aquarius paludm paludum and Hydrochara a nis, categorized as "flight dispersers, " which might immigrate rapidly from the non-inundated rice fields or wetlands. Stepwise generalized linear models suggested that larval abundance of Cx. inatomii in the pools studied was affected by the vegetation cover and habitat type (ground pool or concrete pool), but not by water depth, salinity, presence of predators, and bottom type (sand or concrete) of aquatic bodies. Concrete pools and covered with dense vegetation provide breeding habitat for Cx. inatomii along with their potential predators.