Assassin bugs feed on other insects and sometimes birds and mammals by using some method that puts them into a situation whereby they can then jump upon and feed. Usually coloured dark, they range in size and their heads are segmented from their thorax into a rostrum with a sharp end, which they use to bite and shove into their prey, sending in enzymes for digestion which paralyse and pureé the insides of their victim, which they then slurp out, often leaving just a brittle shell behind. Many species can also shoot venom from their rostrum, as high as a foot in the air, to defend against predators
With about 3,000 species catalogued, assassin bugs are classed as Insecta, and a sub-order of Hemiptera (which also include water boatmen and striders, bed bugs, and stink bugs) called Heteroptera. Technically, an insect called a bug is one with sucking mouthparts; some use it to drain juices from plants, others from creatures.
There are many ways assassin bugs approach and surprise their prey.
One, Stenolemus Bituberus, is a spider hunter found in Australia that usually stalks in a slow dance along a spider's web behind their victim and then leaping and stabbing it. It also uses a technique of sitting on the web and strumming the web in a mimicry of a weakly struggling captive (never a strong one, or that of one landing on the web, or even that of a leaf hitting a web). With this vibration, the formidable spiders would be lured to move down the web slowly and without caution, making an easy target for the assassin bug's attack. The bugs also use a small breeze blowing on webstrands as cover to sneak up behind a spider and attack.
Other assassin bugs:
In a former entry, Bitriot wrote about a species that feeds on bedbugs and thus bites humans as they sleep:
"A painful biter is the masked hunter (Reduvius personatus), often found in houses where it preys on bedbugs and other insects. The adults often bite humans around the mouth (presumably attracted by carbon dioxide or elevated heat emitted from the area), hence its other common name, the kissing bug. In Central and South America certain species of the Mexican Bedbug are the vectors for a highly fatal disease known as Chagas disease."
Tem42 added something interesting about Chagas disease:
"Charles Darwin's lingering death is attributed by some to Chagas Disease. This suspicion was created by Darwin himself, in Naturalist's Voyage; Darwin gives an account in which he, out of curiosity, watched an assassin bug fatten itself on his blood. Presumably, the heart failure that finished him off would have been brought on by the disease. One of the best accounts of this theory of Darwin's death can be found in "Darwin, Chagas', Mind and Body" by Jared Haft Goldstein."
Metacognizant also contributed:
Some assassin bugs are known to exhibit complicated patterns of behavior mirroring those of some animals--"The assaisin bug... has camouflaged itself chemically and tactilely by glueing bits of termite nest all over its body. In this way it is able to capure a termite at the opening of the nest without alarming the soldier termites. After sucking out the termite's semifluid organs, the assasin bug juggles the empty exoskeleton in front of the nest opening in order to attract another termite worker, which will normally attempt to consume or dispose of the corpse. When the second termite worker siezes the first, it is then captured and consumed itself... and the process may be repeated several times by the same assasin bug." Quoted from Donal Griffen's work Animal Thinking, wherein he cites D.A. McMahan's "Bait and Capture Strategy of Termite Eating Assasin Bug." Isectes Sociaux 29:346-51.
There are also bugs that cover themselves with ants. Acanthaspis Petax glues the corpses of many ants it has sucked the life out of all over itself, thought to do so as protection by breaking up the vision of a predator, as well as the natural defence ants have chemically.
Assassin bugs are tool-using, masters of disguise and mimicry, and cunning strategists. Who knows what else we will learn of them?