ASSASSIN BUGS

Assassin bugs, sometimes known as conenoses or "kissing bugs", are occasionally found in the home (bathtubs, sinks, drains, windows). The assassin bug is considered a beneficial insect because it preys on other obnoxious insects, however, when found inside the home in large concentrations it is considered a pest insect.

The assassin bug preys on other insects and benefits people because they help reduce populations of certain pest species. However, if a large number have over-wintered in your home, and are gathering in the windows or anywhere in your home or business en masse, they should be treated. Never handle assassin bugs as they can inflict a very painful bite to humans, causing a severe reaction in some persons. In fact, some of their species have the most painful bites caused by insects.

Nearly 3000 species of assassin bugs exist and scientists feel that many more will be discovered.  These insects can be commonly found throughout most of the world.  They vary in size from a few millimeters to as much as 3 or 4 centimeters.  They come in many colours and shapes and most species have two pairs of wings.  However, all assassin bugs have a powerful curved rostrum, or beak, that they use to pierce and suck out the tissues of their prey. Some assassin bugs are attracted to lights and require blood meals to complete their development. Many are bloodsucking parasites of mammals, including humans. Others are predators, feeding on bed bugs, flies, caterpillars and other insects.  Most are found in late June to early August.  These bugs have a long narrow head, short beak (three-segmented), long slender antennae (four-segmented), and an abdomen often widened at the middle exposing the margins of the segments beyond the wings. Occasionally, they are confused with the leaf footed bug which is distinguished by its flattened (leaf-like) hind legs.

Identification, Biology, and Behaviour

Assassin bugs feed by external digestion, which means that they push their beak into their victim's body and inject a very toxic, or poisonous liquid that affects the nerves and liquefies the muscles and tissues of their prey.  Most other insects that eat like this have two tubes in their beak; one for injecting the fluid and one for sucking in their food.  But, assassin bugs have only one large tube that does both jobs.  This larger tube allows them to inject a larger amount of the toxic digestive fluid so that prey many times their size can be quickly overcome.  Once the insides of the prey are turned into a liquid, the assassin bug uses its rostrum to suck out the liquefied tissues in much the same way we use a straw to drink a milkshake!

Assassin bugs get their name because of the speed that they have to grab and poison their prey.  They are carnivorous, or meat eaters, and use their powerful, jack-knife forelegs to grab their prey.  They have sticky pads on these front legs, made up of thousands of tiny hairs, that stick to their victims and keep them from getting away.  Some assassin bugs actively hunt their prey, while others patiently wait until their prey comes close enough to grab.

The saliva of the assassin bug starts to work almost immediately.  Cockroaches have been seen to die in only 3 to 4 seconds, and caterpillars more than 400 times their weight can die in only 10 seconds! A feast this size can last an assassin bug for days or even weeks. Not all assassin bugs feed on insects and other invertebrates.  Some tropical species attack mammals, birds, and reptiles and actually suck their blood!

Most assassin bugs lay their eggs in the autumn in cracks and crevices that contain lots of leaves.  The eggs hatch in the following spring and the nymphs look very much like the adult, except they are smaller.  Assassin bugs go through incomplete metamorphosis (egg-nymph-adult). After hatching from the egg, the nymph passes through five instars (growth stages). The nymph molts at the end of each instar, becoming an adult after the final molt.  Adults often are the stage that live through winter, and they begin a new generation in spring.

Species of Assassin Bugs

Although there are over 3000 species of this predacious bug, we feature the following for your reference:

Masked Hunter
Adults are 3/4 to 7/8 inch long, chocolate brown, beak curved (not slender and tapered), with slender antennae and walking-type legs. They are called "kissing bugs" and are attracted to lights.  They are very active and enter houses in search of bed bugs, flies, and other insects. Eggs are laid singly in the dust in cracks and corners. Nymphs have the body, legs, and antennae covered with a sticky substance to which dust and lint adhere especially on the head (thus, the name, masked) and are only visible when moving.  Nymphs hibernate in the 4th to 5th instar and reach maturity the following spring. Bites are very painful on humans.

Black Corsair
Adults are black and 9/16 to 11/16 inch long. They resemble the masked hunter except have short wings. Adults over-winter under stones and are collected in early spring. Bites are painful to humans.

Spined Assassin Bug
Adults are 1/2 to 9/16 inch long, brown coloured, narrow, angular, and rough-bodied. The head, thorax (middle part) and front leg (upper portion) are covered with spines and the female's abdomen is wavy. Cylindrical white eggs are laid in small groups covered with a reddish secretion.  These bugs are very beneficial to agriculture, feeding on many injurious insects, attacking all stages of the Mexican bean beetle.

Bloodsucking Conenose
Adults are 3/4 to 13/16 inch long, brownish-black, broad, stout-bodies with six reddish orange spots on each side of the abdomen, above and below. Eyes are large with an elongate protruding head.  The beak is not curved (slender and tapered) and almost bare.  It is kept folded back between the front legs when not used.  Adults are winged and able to fly. They are found in nests of rats and will feed on any animal including humans. Oval, pearly-white eggs are laid singly from May to September.  Each batch is laid after a blood meal. Nymphs have eight instars requiring three years for the life cycle.

The conenose is a vector of Chagas disease prevalent in Mexico, Central America, and South America, where these bugs may colonize human habitations. This sometimes fatal disease, caused by a flagellate protozoan, has symptoms of swelling of the eyelids and face, loss of nervous control, high fever, anemia and destruction of the cardiac and skeletal muscles. This disease is not common in North America.

The bloodsucking bugs are active at night usually feeding on sleeping victims. These bugs are usually found outdoors in hollow trees, in raccoon and opossum dens, or near wood rat nests. Indoors, they are found in bedding, floor and wall cracks, under furniture, etc. They are poor fliers and sometimes attracted to lights. Bites are sometimes painless, but may cause a severe reaction. They are more often a problem to people living in wooded areas.

First Aid and Control Measures

Bites may be hardly felt by the bloodsucking conenose in contrast to painful bites by the masked hunter, black corsair, and wheel bug. Sensitive individuals may experience burning pain, intense itching and much swelling with red blotches and welts over the body. If bitten, remain calm and safely collect the bug for positive identification. Do not handle bugs without gloves. Contact your local poison information center to seek medical help. Relief from bites may be obtained by using lotions containing menthol, phenol, or camphor.

All potential breeding areas such as rodent and bird nests and trash piles in or near houses should be eliminated.  Since these bugs fly at night and are attracted to light, adequate screening must be used around windows and doors.  Use non-attractive insect yellow lights, if possible. Be sure to caulk and seal any openings into the house. Should a bug alight on one's face or hand, it should be brushed off gently since it is likely to bite if pinched or crushed. Usually only a few individual bugs are found in the home at one time except for the bloodsucking conenose, which may be in groups of 10 to 15 at a time or scattered singly. Do not handle the bugs. Use a broom and dustpan or vacuum cleaner to collect and discard individuals.