Ladybugs, recognized by their distinctive spots and bright coloration, are familiar insects often regarded as beneficial garden inhabitants. Despite their common presence, many animals consume them. Understanding what preys on ladybugs reveals interesting aspects of their natural defenses and ecological interactions.
Ladybug’s Natural Defenses
Ladybugs possess several defense mechanisms that deter many predators. Their striking red, orange, or yellow bodies with black spots serve as a warning signal, known as aposematic coloration. This display warns animals of their unpalatability or toxicity. The intensity of their color can even correlate with higher toxicity levels.
When threatened, ladybugs engage in reflex bleeding, secreting a foul-smelling, bitter-tasting fluid called hemolymph from their leg joints. This hemolymph contains toxic alkaloids, making them unappetizing. This defense, combined with their warning colors, often causes predators to avoid or quickly drop the insect.
Vertebrate Predators
Despite these defenses, some vertebrate animals occasionally prey on ladybugs. Birds like swallows and crows consume them, though ladybugs are not a primary food source for most avian species. Many birds learn to avoid these insects after an unpleasant experience.
Amphibians like frogs and toads also eat ladybugs. These predators often rely on movement to detect prey and may consume ladybugs opportunistically, as their ability to discriminate against chemically defended insects is limited. Salamanders also occasionally eat ladybugs. Reptiles such as lizards might also prey on ladybugs if encountered.
Invertebrate Predators and Parasites
Invertebrates represent another group of animals that prey on or parasitize ladybugs. Generalist predators like spiders readily consume ladybugs caught in their webs. Other predatory insects, including assassin bugs and praying mantises, also capture and feed on ladybugs. Dragonflies also prey on ladybugs.
Ladybugs are also hosts for specialized parasites. Parasitic wasps, notably Dinocampus coccinellae, lay a single egg inside a living ladybug. The wasp larva develops inside, consuming its internal tissues without immediately killing the host. Once mature, the larva emerges from the ladybug’s abdomen and spins a cocoon between its legs, leaving the ladybug alive but often paralyzed, guarding the wasp’s cocoon.
This “zombification” behavior is thought to be induced by a virus transmitted by the wasp, affecting the ladybug’s brain and causing paralysis and tremors. Additionally, parasitic flies, such as scuttle flies (Phalacrotophora genus) and tachinid flies, can parasitize ladybug pupae or adults, with their larvae developing inside the beetle.