The family Reduviidae, commonly known as assassin bugs, represents a vast and diverse group of insects found across the globe. With approximately 7,000 described species, this family is one of the largest within the order Hemiptera, the true bugs. They are characterized by a sturdy build, a narrow neck-like structure, and a formidable piercing mouthpart.
The General Predatory Diet
Most assassin bugs are highly effective generalist predators, feeding almost entirely on other invertebrates. They consume a wide assortment of insects, often targeting species considered pests in agricultural and garden settings. This broad menu includes numerous soft-bodied insects and the larvae of many species.
Common prey items frequently include aphids, leafhoppers, thrips, and mites, which are often found on plant foliage. They also readily attack and consume larger, more robust garden pests such as caterpillars and adult beetles, along with their eggs and larvae.
Feeding Mechanism and Hunting Strategy
Their hunting strategy often involves a combination of stalking or ambushing, patiently waiting for an unsuspecting insect to pass nearby. Some species, like the Zelus genus, even possess a sticky substance on their legs that helps them secure their victims.
Once a target is within reach, the assassin bug quickly pins it down with its forelegs and uses its short, three-segmented rostrum, or beak, to pierce the exoskeleton. A complex saliva is injected, which contains powerful neurotoxins to quickly paralyze the victim, followed by digestive enzymes.
The digestive enzymes begin to break down the internal tissues of the prey while it is still alive, a process known as extracorporeal digestion. After the internal contents have been completely liquefied, the assassin bug uses its rostrum to suck out the resulting “soup.”
The Specialized Diet of Blood Feeders
A notable exception to the predatory lifestyle exists within the family, specifically the subfamily Triatominae, which includes the insects commonly known as kissing bugs. These species have undergone a complete dietary shift, specializing in hematophagy, which is the consumption of vertebrate blood.
Kissing bugs feed on the blood of various vertebrates, including mammals, birds, and reptiles. They are primarily nocturnal feeders, often biting hosts while they are sleeping, with a preference for thin-skinned areas like the face. The saliva of these species is adapted to prevent blood clotting, facilitating a smooth meal, unlike the venom of their predatory relatives.
This specialized diet is a matter of public health concern because many species in the Triatominae subfamily transmit the parasite Trypanosoma cruzi. This parasite is the causative agent of Chagas disease, a serious illness endemic to the Americas. The insects are vectors, passing the parasite through their feces, which they often deposit on the host during or shortly after feeding.
Ecological Role in Pest Control
By feeding on a broad range of phytophagous (plant-eating) insects, the majority of assassin bug species serve as a form of natural biological control in natural ecosystems and agriculture. In gardens and crop fields, their presence is often welcomed because their hunting activity reduces the need for chemical interventions.
Although their generalist appetite means they occasionally consume other beneficial insects, their overall impact remains highly desirable. Their predatory role helps protect plant life by consuming large numbers of common pests and maintaining balance among insect communities.