Stretchy Membrane Aids Oviposition

a brown locust insect with red legs lays eggs in brown soil with a blurry brown background

Biological Strategy

Locust

AskNature Team

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Expel Solids

Living systems must often discharge solids–such as seeds, eggs, pollen, and mineral salts–for reproduction, protection, or other reasons. Solids can be easily moved when a living system applies force to them. But creating that force requires energy, so living systems must either have efficient strategies worth the energy investment or use an outside force (such as gravity). For example, a tropical mistletoe positions its pollen so that the weight of a bird landing nearby triggers the pollen’s release onto the bird’s forehead. The bird then fertilizes other mistletoes that it visits.

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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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The intersegmental membranes of a pregnant female locust helps her deposit her eggs about 8 centimeters underground due to stress-softening of the membrane.

“While a stretchy nuchal ligament can act as a shock absorber, a stretchy tendon would undo the shortening of the muscle that it attaches to a bone. The current record holder, the intersegmental membrane of the pregnant female locust, achieved its renown in an investigation by Vincent (1975); it’s made of about 12 percent and 12 percent chitin, with the rest water, and it undergoes something called ‘stress-softening.’ Mother locust, a creature of dry habitats, stretches these membranes between her abdominal segments to get her eggs about 8 centimeters underground–deep enough so the desiccated eggs have a reliable source of water. The eggs are kept fairly dry before being expelled, presumably so the locust can hold a large number and still fly.” (Vogel 2003:314)

Vogel S. Comparative Biomechanics: Life’s Physical World. Princeton: Princeton University Press; 2003. 580 p.