Poisonous Secretions Deter Predators

a bright shiny green insect sits on a green plant against a blurry background

Biological Strategy

Lytta spanishfly

AskNature Team

Image: Siga / Wikimedia Commons / CC BY - Creative Commons Attribution alone

Protect From Animals

Animals–organisms that range from microscopic to larger than a bus–embody a wide variety of harms to living systems, including other animals. They threaten through predation, herbivory, defense, and parasitism, and they compete for resources such as water, nutrients, and space. Any given living organism commonly faces threats from a variety of animals, requiring strategies that effectively defend from each. Trout and other bony fish, for example, escape predators by having scales made of very thin, flake-like pieces of bone covered with slippery mucus. They also have behavioral strategies such as camouflage, fast swimming, and twisting and turning to achieve release from a predator’s grip.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Secretions of blister beetles help deter predators by containing cantharidin, a poisonous chemical.

“Other animals that autohemorrhage come from various insect families within the beetle order Coleoptera…Another is Lytta vesicatoria from the oil beetle family, commonly known as the blister beetle. These creatures secrete a liquid called cantharidin which, when in contact with human skin, causes it to blister. The liquid has valuable medical properties, and is often used as a treatment for skin complaints such as warts.” (Shuker 2001:130)