Egg of insects

Definition

The female gamete and initial developmental stage of insects, typically deposited outside the maternal body (oviparity), though some species retain eggs internally (ovoviviparity) or nourish embryos directly (viviparity). Insect eggs are highly diverse in size, shape, surface sculpturing, and protective coverings (chorion), reflecting adaptations to aquatic, terrestrial, parasitic, or endophytic environments. Most contain sufficient yolk to sustain embryogenesis until hatching, with development time varying from days to years depending on temperature, diapause, and species biology.

Etymology

From Middle English egge, from Old Norse egg, akin to similar Germanic words for bird and reptile eggs; applied to insect reproductive structures by extension.

Example

The eggs of the monarch butterfly (Danaus plexippus) are conical with longitudinal ridges, laid singly on milkweed leaves; those of the grasshopper Melanoplus are elongate and deposited in soil pods, while parasitoid wasps inject eggs directly into host larvae.

Synonyms

• Ovum

Related Terms

• oviposition
• Chorion
• embryo
• larva
• oviparity
• ovoviviparity
• Diapause
• egg pod
• Micropyle

Usage Notes

The term 'egg' in entomology usually refers to the entire structure including protective layers, not merely the female gamete (ovum). Specialists distinguish 'egg' (post-oviposition stage) from 'ovum' (pre-fertilization gamete). Plural 'eggs' is standard; 'ova' appears in formal embryological contexts. Contrast with 'cyst', 'resting stage', or 'pupa'—terms sometimes misapplied to dormant eggs. In aphids and some flies, 'egg' may refer to overwintering diapausing stages versus parthenogenetic live births in summer generations.