Nesting Behavior of Anoplius liukiu, in Comparison with Another Semi-aquatic Spider Wasp, A. eous (Hymenoptera, Pompilidae)

Anoplius liukiu (DALLA TORRE) exhibits several characteristics in its nesting behavior. Females build their nests in the ground before hunting. They transport prey walking backward on the ground, grasping it in their mandibles by the base of the legs. Alternatively they may drag it forward along the surface film of the water, using their wings for locomotion, grasping it by the middle of the first or second leg, as do females of A. eous YASUMATSU. Their nests are often excavated in pre-existing large burrows opening into stream banks and contain 1-4 cells. Their prey consists of immature or adult males and females of Pardosa pseudoannulata (BOSENBERG et STRAND) (Lycosidae). Other prey taken was an adult female of Pirata clercki (BOSENBERG et STRAND) (Lycosidae) and a juvenile of Coelotes sp. (Agelenidae). Nesting behavior and some morphological characteristics of this species are compared with those of A. eous, which occupies the same habitat as A. liukiu but is more versatile in its nesting and more adapted for a semi-aquatic mode of life.