Buzz
While many predatory insects, such as hornets and mantids, are widely recognized for their aggressive nature and ability to prey on almost anything they encounter, there are other arthropods with highly specialized diets and unique hunting strategies that set them apart.
10. Ant-Eating Paussinae Beetles
Paussinae, a rare and peculiar subfamily of bombardier beetles (adult shown above), typically inhabit ant nests, feeding on both adult ants and their larvae. These beetles are notable for their larvae, which feature a terminal disk—a unique, fan-shaped structure at the end of their tails.
In numerous species, the terminal disk emits an enticing scent and functions like an additional set of jaws, snapping shut on unsuspecting prey. Alternatively, some species bury themselves headfirst, using the disk to seal their burrow. When ants step on this sensitive tail structure, they are ambushed.
9. Brachyspectra Fulva
The larvae of Brachyspectra fulva share some similarities with Paussinae larvae, particularly in their ambush tactics using their tails. These larvae are remarkably flat, resembling a rug, and are equipped with a single, sharp spike at their rear, akin to a thick nail.
These larvae primarily prey on spiders, much like the Paussinae, and produce a chemical lure to attract their victims. The spider, drawn to the scent, unknowingly steps onto the camouflaged larva, only to realize too late that it has stumbled into a trap. The spider is swiftly ensnared between the larva’s powerful jaws and tail, reminiscent of a cartoon character stepping onto a giant, red “X” marking an obvious trap.
8. Ant-Eating Slug Maggots
The larvae of the Microdon mutabilis fly (adult shown above) are so bizarre in appearance that they were once misclassified as a type of slug. Their bodies are smooth, dome-shaped, and covered with a thick, rubbery texture.
These maggots can spend up to two years inside ant colonies, surviving by consuming ant eggs and larvae. Remarkably, the ants often remain oblivious to their presence, likely because the maggot emits a scent that mimics the colony’s own. Even if an ant becomes suspicious, the maggot’s sleek, smooth body and suction-like underside make it nearly impossible for the ant to grasp or attack.
7. Spongillaflies
While antlions are well-known for their ingenious sand traps, their relatives in the Sisyridae family, known as spongillaflies, exhibit even more peculiar behaviors. These insects are truly unique in their habits and adaptations.
During their larval phase, these insects live underwater and are classified as carnivores, despite feeding on defenseless freshwater sponges. Using their slender, elongated mouthparts, the larvae pierce the sponge’s structure and extract its fluids. Few are aware that freshwater sponges even exist, and even fewer know about the specialized insect that preys on them.
6. Snail-Eating Caterpillars
Among the rare carnivorous caterpillars, most are found in Hawaii. The most unusual of these is a species that feeds solely on small snails, employing a complex hunting strategy.
The caterpillar constructs a durable silk case, similar to a bagworm’s. When it locates a snail, it positions the case beneath the shell’s edge, using silk to immobilize the snail, preventing it from escaping or retreating into its shell.
5. Parasitic Wasp–Hunting Wasps
Parasitic wasps are well-known for laying their eggs inside other insects, where the hatched larvae consume their host from within. However, the trigonalids take this behavior to an extreme level.
Rather than depositing a few eggs directly into a caterpillar, the female trigonalid scatters up to 10,000 eggs on leaf edges, where caterpillars are likely to ingest them. This strategy increases the likelihood that some eggs will end up in caterpillars already hosting other parasitic wasp larvae, which become food for the trigonalid larvae. While this might seem beneficial to the caterpillar, the trigonalids ultimately consume it from the inside as they emerge.
4. Head-Stealing Flies
If you’re fascinated by strange insects, you might have come across stories of tiny flies that grow inside the heads of fire ants, eventually causing the ant’s head to fall off. These flies have a relative that takes this gruesome behavior to an even more extreme level.
Female flies of the genus Dohrniphora don’t wait for a parasitic phase. Instead, they target ants that are injured, trapped, sick, or dying. Equipped with a serrated blade on her abdomen, the fly cuts and saws at the ant’s neck until the head is detached. She then drags the head away and deposits her eggs inside it.
3. Frog-Hunting Ground Beetles
While some predatory insects occasionally consume vertebrates, and others parasitize them, the two beetle species of the genus Epomis are unique in their exclusive focus on hunting and killing vertebrates. Entomologist Gil Wizen conducted extensive research on these beetles, spending four years studying their behavior before publishing a comprehensive paper on these cunning and deadly insects.
As larvae, these beetles prey exclusively on frogs, exploiting the fact that beetle grubs are a common food source for amphibians. When a frog approaches, the larva doesn’t flee or move closer but instead wiggles its antennae to lure the frog. Once the frog is within reach, the larva swiftly turns and sinks its hooked mandibles into the frog’s throat, making it nearly impossible for the amphibian to escape as the larva begins consuming it from the inside.
Wizen documented instances where a frog managed to swallow an Epomis larva, only for the larva to persist in its assault from inside. The frog would eventually regurgitate the larva, only to face further attacks from the relentless predator.
As adults, Epomis beetles become more versatile hunters, targeting a range of small prey. However, when encountering a frog or toad, they employ specialized tactics, evading the amphibian’s mouth, climbing onto its back, and delivering a paralyzing bite to the spinal cord. Whether as larvae or adults, these beetles spell doom for frogs, a fitting reversal given how many insects fall victim to amphibians.
2. Snake-Eating Beetle
Typically, burying beetles (also known as “grave digger beetles”) consume the carcasses of small animals, burying them to provide food for their offspring. However, one species has adopted an even more macabre approach. Few insects can boast a more astonishing claim than being a “snake embryo parasitoid.”
Nicrophorus pustulatus will feed on carcasses if necessary, but it prefers to lay its eggs in snake nests. Upon hatching, the larvae penetrate the soft shells of snake eggs, devouring the embryos and yolks over several days, much like they would with a dead bird or rodent. This makes the beetle the only known insect to act as a brood parasite—stealing nests—from a vertebrate. The mother snake remains oblivious as some of her eggs hatch into small black beetles instead of baby snakes.
1. Swimming Microwasps
Fairy wasps, also known as fairyflies, are among the smallest insects and some of the tiniest multicellular organisms ever discovered. They can be smaller than a single-celled amoeba, so minuscule that you might inhale them without noticing, as they are tinier than most dust or pollen particles in the air.
Despite their charming name, these nearly invisible “fairies” are parasitic wasps. They deposit their eggs inside the eggs of aquatic insects. Remarkably, their tiny wings serve a dual purpose, enabling them to fly through the air and swim underwater.
