Anoplius depressipes

Banks, 1919

Anoplius depressipes is a spider wasp in the Pompilidae, notable for its specialized hunting of fishing spiders in the Dolomedes. The exhibits remarkable aquatic adaptations, including the ability to walk on water and dive underwater for several minutes to capture prey that attempts to escape beneath the surface. This represents a striking example of -prey with semi-aquatic spiders.

Anoplius depressipes by (c) Gerry van Tonder, some rights reserved (CC BY), uploaded by Gerry van Tonder. Used under a CC-BY license.

Spider wasp male (Pompilidae, Anoplius depressipes) (41210542172) by Insects Unlocked from USA. Used under a CC0 license.

Spider wasp female (Pompilidae, Anoplius depressipes) (41210539412) by Insects Unlocked from USA. Used under a CC0 license.

Pronunciation

How to pronounce Anoplius depressipes: /əˈnoʊpliəs dɪˈprɛsɪpiːz/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other spider wasps by its association with aquatic and documented of pursuing spiders underwater. Most Anoplius are black or blue-black with limited distinguishing field marks; positive identification requires microscopic examination. Similar in general form to other Pompilidae but provides the primary distinguishing characteristic.

Images

Habitat

Aquatic and semi-aquatic environments including ponds, lakes, and quiet river backwaters where fishing spiders (Dolomedes) occur. Associated with emergent vegetation and floating objects in still water.

Distribution

North America; specific range details not documented in available sources.

Diet

of fishing spiders in the Dolomedes ( Pisauridae). Has been observed capturing spiders that retreat underwater to escape.

Host Associations

Dolomedes triton - preySix-spotted Fishing Spider, known to dive underwater to escape this
Dolomedes - prey of fishing spiders, semi-aquatic prey

Life Cycle

Solitary with typical pompilid : female paralyzes spider prey, transports to burrow, lays single on paralyzed , and seals burrow. Larva consumes the living but paralyzed spider.

Behavior

Highly adept at on water surface. Capable of submerging for several minutes to sting and extract spiders hiding underwater. This underwater hunting is exceptional among spider wasps.

Ecological Role

of large semi-aquatic spiders; control of fishing spiders. Contributes to aquatic-terrestrial connections.

Similar Taxa

Anoplius aethiopsSimilar large black spider wasp, but hunts terrestrial wolf spiders (Lycosidae) rather than aquatic spiders
Anoplius cleoraClosely related and morphologically similar; requires microscopic examination to distinguish
Other Anoplius speciesMost are black or blue-black with limited external differences; and prey type are key distinguishing factors

More Details

Aquatic Adaptations

The 's ability to walk on water and dive after prey represents a specialized rare among spider wasps. The fishing spider Dolomedes triton has been documented diving to escape this , using trapped air on body hairs to breathe underwater temporarily.

Predator-Prey Dynamics

This exemplifies an evolutionary arms race with its spider prey: the spider's diving escape is countered by the 's ability to follow underwater, while the spider's surface-wave detection abilities help it detect approaching wasps.