Velia caprai

Velia caprai, known as the water cricket, is a species of aquatic bug found in Europe.

Velia caprai
Nomenclature
Binomial name	Velia caprai Tamanini, 1947
Common name	Water cricket
Native name	Capra’s water cricket
Taxonomy
Phylum	Arthropoda
Order	Hemiptera
Suborder	Heteroptera
Superfamily	Gerroidea
Family	Veliidae
Subfamily	Veliidae
Genus	Velia
Species	Velia Caprai
Conservation status	Least concerned

Description

The adult insect grows to a length of 6.2–8.5 millimetres (0.24–0.33 in)Members of the family Veliidae resemble the pond skaters of the family Gerridae, but with stouter middle and hind legs, and a generally stouter appearance. V. Caprai had an overall black colouration with bright red transverse stripes along the abdomen. Both Apterous as well as winged individuals have been observed

Ecology

Defence mechanism

Checimal defence

Velia Caprai has a chemical defence mechanism, the noticeable transverse red band’s present on the abdomen advertising Their irksome taste. V. Caprai is distasteful for the brown trout, most individuals consumed by the large trout are generally ejected alive and unharmed V. Caprai are gregarious and often aggregate in large numbers in order to prevent predation.

Thanatosis

V. Caprai will also use tonic immobility (Thantosis) as a defensive response against predation thanatosis posture is either symmetrical with legs held to the sides or an irregular posture

Hunting

V. Caprai face upstream & use protrusions on floating vegetation as anchoring points often grasping onto projections using legs on the corresponding adjacent sides. Any ripples on the surface of the water, by any prey item is perceived by the insect which then proceed towards the focus of the activity. Large prey is conveyed onto land for consumption carried at the tip of the rostrum.

Life cycle

Eggs are laid loosely in rows on floating vegetation or moss. Female’s outlive the males and can be observed throughout most of June; adults can live upto two winters which is unlike other semi aquatic insects, Temperate water striders (Gerridae) overwinter as adults and die after spring reproduction. European water cricket Velia caprai (Veliidae) overwinters concurrently in egg and adult stage in Central Europe. This rare overwintering strategy goes with longevity of this species. 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.

Behavior

Expansion Skating

One unusual behaviour exhibited by Velia caprai is called "expansion skating", or Entspannungschwimmen (German for "relaxation swimming"), in which saliva is ejected from the insect's beak onto the surface of the water, lowering the surface tension and allowing the insect to travel at up to twice its normal speed.

Occurrence

Range

V. Caprai is widespread throughout the UK and is fairly common in Britain.

Habitat

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 or Brooklime V. Caprai exclusively inhabit running water usually confined to rivers, streams but will also inhabit lakes and ponds with some water movement.