The photographs for this page are currently missing. Four images were published here; all four are dead links on the server as at 4 September 2026, and the originals have not yet been recovered. The text below is kept because the observation in it is worth keeping. The page will be restored with its photographs when they are found.
An assassin bug photographed in Tawau, Sabah. The insect was handled, and it bit.
The bite was on the neck. It was not painful, left no mark, and had no after-effect on the skin. What was alarming was not the bite but the grip: trying to lift the insect off, its claws held so tightly to the skin that it had to be pulled away hard. Held between the fingers the animal felt distinctly rough — and the photographs explain why. Its front legs carry spines and dense hair.
That detail is worth pausing on, because it is a family character observed from scratch. Assassin bugs catch prey with raptorial front legs covered in hairs and spines. The roughness felt between finger and thumb is the gripping apparatus of a predator, and it is exactly why the insect was so hard to detach.
Not recorded: the date, the precise locality within Tawau, the body length, and what the insect was on when found. If these can be recovered they should be added — they are what turns a photograph into a record.
Established: order Hemiptera, suborder Heteroptera, family Reduviidae — the assassin bugs.
Not established: the genus and species.
A name previously published on this page has been withdrawn. This page formerly gave the insect as Zelus tetracanthus, following an identification made from BugGuide. That name cannot be correct. Zelus is endemic to the New World: the 2016 revision of the genus states it occurs naturally in the Caribbean and in all but one of the continental American countries, with introductions only to Pacific islands, Europe and Chile. Z. tetracanthus itself is recorded from the Caribbean, Central America, North America and South America. Borneo is not in its range, and BugGuide is a North American identification resource — a good one, but the wrong region for a Bornean animal.
What would settle it: Reduviidae is a large family and Borneo's fauna is substantial. Genus determination generally needs the head and pronotum shape, the structure of the rostrum and its groove on the prosternum, and often the male genitalia. The practical route is to post the photographs, once recovered, to iNaturalist, where heteropterists are active.
Most assassin bugs are predators of other arthropods; a minority are blood-feeders. They seize prey with the raptorial forelegs and feed through a three-segmented rostrum that folds back into a groove on the underside of the thorax when not in use. As in all Hemiptera the mouth is a piercing-sucking apparatus, not a set of jaws.
Some species do come indoors and hunt household insects. The masked hunter, Reduvius personatus, is the best-documented example: it takes woodlice, lacewings, earwigs, termites and bed bugs, and turns up in houses that have a bed bug problem. It is not, however, a Bornean species, and whether the Tawau animal photographed here takes cockroaches is not established — that was an assumption carried over from the withdrawn identification, and it is not repeated as fact.
On the bite: it varies a great deal between species. This one caused no pain and left no mark. The masked hunter's bite, by contrast, is described as a rostral stab comparable to a bee sting, with swelling lasting about a week. Assassin bugs are worth respecting rather than fearing, and worth not picking up casually.
© Wong Fook Yee. Page reviewed: 4 September 2026.