Velia caprai is a common water cricket across Northants living mainly on the surface of running water in open water of sheltered streams & ditches, sometimes margins of pools. Normally water margins vegetated, e.g. overhanging grasses, or emergent vegetation such as watercress (Rorippa) or brooklime (Veronica beck-bunga). Gregarious, often in large aggregations (BN, 2008).

Protrusions are used as anchoring points, the bugs facing upstream and holding the projection by the legs of the adjacent side. Ripples emitted by insects or spiders on the surface film are perceived and the bug advances to the source to feed, ultimately using eyesight. Large prey are conveyed to the land for consumption, carried at the tip of the rostrum.

Eggs are laid loosely on moss in late May and early June; old overwintered females outlive the males and can be found through most of June. Egg and larval development together take about 7 weeks and by late July some of the new generation are adult, the bulk being present by late August. Thus there is one generation a year. However, local differences may exist to give two annual generations (SWL, 1959).

Distribution:

Found in 65 sites and 28 10km squares this is categorised as very common in Northants.

Habitat:

It is found on water bodies with some flow, streams rivers, ditches, ponds and river backwaters usually where there is some marginal vegetation in contrast to Velia saulii that prefers bare margins.

Identification:

The two species V.caprai and V.saulii can be tricky to tell apart with females being easier to identify than males. Males have two spines on the hind femur and the black markings on the connexivum are smaller and always triangular where rectangular in V.saulii. Females have the connexivum folded flat against the upper side of the abdomen, the apical tip pointing upwards, the pronotum is shorter, the hind edge slightly concave and metatonum exposed.