How Are Fleas Triggered to Emerge From Diapause?
WouterDiapause in fleas is triggered by a variety of factors. For starters, photoperiod plays a critical role. During this phase, the flea ceases morphological development, including growth and moulting. It also changes color. It may also undergo changes in enzymes responsible for cold hardening. Fire bugs, for example, accumulate polyhydric alcohols, which lowers their freezing point. This helps them survive the winter and may lead them to seek out suitable overwintering sites.
Diapause is also triggered by the availability of food. Food is available in the form of vertebrate carcasses, which makes the diapause phase an ideal time for the insect to feed. Moreover, a reduction in temperature inhibits growth of pathogens. However, in the tropics, where temperatures are high, predators and parasites may be abundant during the diapause stage.
The Indian mealmoth, for example, diapauses in various developmental stages depending on temperature. The temperature of a desert locust’s habitat also affects its reproductive development. Another factor that regulates diapause is the production of gibberellin, a hormone produced by plants. Gibberellin stimulates reproductive development in desert locusts.
Adult fleas will not emerge from their pupal cocoons until they detect a potential host. They may also be triggered by vibrations, rising carbon dioxide, or human body heat. Once they find a suitable host, they will begin to feed and breed. Then, within a few days, they will lay eggs.
