This chapter discusses protective coverings females provide their eggs, which reflect the full range of environments exploited by insects. Egg coverings fall into two major categories: those produced by follicle cells and those produced by accessory glands of the reproductive tract. Follicle cells secrete the chorion or insect eggshell. The design of the chorion is important in fertilization, egg respiration, and water balance. Coverings produced by accessory glands provide additional protection from the elements, predators, and parasites. The vitelline envelope is considered to be the first layer of the chorion. Next, a layer of wax is secreted, giving the egg greater resistance to desiccation. Then, several more chorionic layers are produced, commonly with sheet-like inner and outer layers separated by a pillared region enclosing air spaces. The eggshell is a layer of armor protecting the egg and developing embryo from the elements, predators, and parasites. Eggshell shape, texture, and color can also provide protection through camouflage and warning coloration.
|Original language||English (US)|
|Title of host publication||Encyclopedia of Insects|
|Number of pages||2|
|State||Published - Dec 1 2009|
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)