Cocoon Provides Hard, Protective Casing

Biological Strategy

Puss moth

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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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Cocoons of puss moths form a hard, protective casing because they are made of labial silk and bark fragments.

“Many adecticous pupae [toothless] are enclosed in cocoons of varying shape and consistency. That of the puss moth (Cerura vinula) is constructed on the boles of willow and sallow and is of extreme toughness, being fashioned from a mixture of labial silk and bark fragments which hardens into an oval whole, rough and bark-like on the outside but glossily smooth inside. Having no biting jaws, pupae of this type need other means to free themselves from their cocoons. The puss moth exudes a special liquid which softens the casing, allowing the moth to push its way out through a relatively small hole; others have special cocoon-rupturing structures on head or thorax which may be lost on emergence.” (Wootton 1984:91)