There are more than 2000 different flea species in the world, with more than 80 species found within Australia. The bodies are covered in long hairs and spines that face backwards, helping them to move through the hair of feathers of the host. Each different life stage is extremely resilient to unfavourable conditions for a long time. The adult flea lays eggs on the host or in a nest. Eggs layed on a host are usually smooth and fall to the substrate, but eggs layed in a nest are sticky. The eggs then hatch into a larva, which rarely feed upon the host, although the larva of Tasmanian Uropsylla tamanica feed upon the Quoll and Tasmanian Devil (Dasyurid). A cocoon is then spun to house the pupa. Fleas are not as specific to a particular host species as some other parasites, jumping from one animal to another. This enhances their likelihood to be a vector of disease. Fleas have no natural predators.
Naumann, I. D & Naumann, I. D & CSIRO. Division of Entomology 1991, The Insects of Australia : a textbook for students and research workers, 2nd ed, Melbourne University Press, Carlton South, Vic