Rove Beetle

One of the lesser seen rove beetle here. Taken at night in Singapore.

Quote from en.wikipedia.org/wiki/Rove_bee…
The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra that leave more than half of their abdomens exposed. With approximately 58,000 species in thousands of genera, the group is currently recognized as the largest family of beetles. It is an ancient group, with fossil rove beetles known from the Triassic, 200 million years ago, and possibly even earlier if the recently described Leehermania proves to be a member of this family. They are an ecologically and morphologically diverse group of beetles, and commonly encountered in terrestrial ecosystems.

One well-known species is the Devil's coach horse beetle. For some other species, see List of British rove beetles.

As might be expected for such a large family, there is considerable variation among the species. Sizes range from <1 to 35 mm (1.5 inches), with most in the 2–8 mm range, and the form is generally elongate, with some rove beetles being ovoid in shape. Colors range from yellow to reddish-brown to brown to black. The antennae are usually 11 segmented and filiform, with moderate clubbing in some genera. The abdomen may be very long and flexible, and some rove beetles superficially resemble earwigs.

Some members of Paederina, a subtribe of Paederinae, contain a potent vesicant in their haemolymph which can produce a skin irritation called Paederus dermatitis.[1] The irritant pederin is highly toxic, more potent than cobra venom.

Rove beetles are known from every type of habitat that beetles occur in, and their diets include just about everything except the living tissues of higher plants, now including higher plants with the discovery of the diet of Himalusa thailandensis. Most rove beetles are predators of insects and other kinds of invertebrates, living in forest leaf litter and similar kinds of decaying plant matter. They are also commonly found under stones, and around freshwater margins. Almost 200 species are known to live on ocean shores that are submerged at high tide, including the pictured rove beetle;[3] other species have adapted to live as inquilines in ant and termite colonies, and some live in mutualistic relationships with mammals whereby they eat fleas and other parasites, benefiting the host. A few species, notably those of the genus Aleochara, are parasitoids of other insects, particularly of certain fly pupae.

Although rove beetles' appetites for other insects would seem to make them obvious candidates for biological control of pests, and empirically they are believed to be important controls in the wild, experiments using them have not been notably successful. Greater success is seen with those species (genus Aleochara) that are parasitoids.

Rove beetles of the genus Stenus are very interesting insects. They are specialist predators of small invertebrates such as collembola. Their labium can shoot out from the head using blood pressure. The thin rod of the labium ends in a pad of bristly hairs and hooks and between these hairs are small pores that exude an adhesive glue-like substance, which sticks to prey.