Siphonaptera, flea
Fleas are always found close by their hosts, either in direct contact such as among the feathers or hair or within their nests. Fleas are found in almost all habitats in Australia where there is a ready host and many native species of flea are closely associated with native marsupials and rodents. The main introduced species are also associated with animals that have been introduced to the country such as the cat flea (Ctenocephalides felis) the dog flea (Ctenocephalides canis) and the rat flea (Xenopsylla cheopis) Image: Cate Lowe
Courtesy Australian Museum, Public Domain, Photographer: Cate Lowe, Date: [year] (This image is in the Australian Museum collection, but copyright has expired. This licence allows sharing, remixing and use for commercial purposes)

Fast Facts

  • Classification
    Order
    Siphonaptera
    Class
    Insecta
    Phylum
    Euarthropoda
    Kingdom
    Animalia

Fleas and tapeworms

Fleas are small, wingless insects ranging in size from approximately 1-10 millimetres in length depending on the species. Almost everybody, especially those with cats or dogs will be familiar with these small biting insects and will have either seen them or the effects of their nuisance bites. Fleas can be recognised by the following features:

  • Laterally compressed bodies
  • Piercing-sucking mouth parts
  • Enlarged hind legs adapted for jumping
  • Strong tarsal claws adapted for holding onto their hosts
  • Backward pointing hairs and bristles for ease of movement through the hair of a host
  • Small antennae which tuck away into special groves in the head

The larvae of all fleas appear grub-like and are usually found in the nests of their host or other areas where they commonly rest.

Feeding and diet

Fleas feed on a wide variety of warm-blooded vertebrates including humans, dogs, cats, rabbits, rats, mice and birds. Fleas normally specialise in one host species or group of species, but can often feed but not reproduce on other species.

Other behaviours and adaptations

In most species, neither female nor male fleas are fully mature when they first emerge but must feed on blood before they become capable of reproduction. The first blood meal triggers the maturation of the ovaries in females and the dissolution of the testicular plug in males, and copulation soon follows.

Life Cycle

Fleas mate on their host animal and lay their eggs either onto the animal where they fall to the nest or directly in the nest. The small larvae hatch from the eggs and do not begin to feed on blood like that of their parents but eat the dead skin and other dirt and dust from the host animal. The larvae develop through 3 instars and when fully grown spin a silken cocoon and pupate in the nest of the host. The vibrations caused by scratching by a host often trigger the emergence of the adult flea from the pupal case, enabling it to immediately find a host and begin feeding. The complete life cycle may take from several weeks to many months depending on the species.

Breeding behaviours

Some species breed all year round while others synchronise their activities with their hosts' life cycles or with local environmental factors and climatic condition.

Predators parasites and diseases

In contrast to fleas, tape worms are endoparasites, as they attach to other animals' guts to absorb nutrients from the food they eat. They live in the small intestines of many different species of animals, including humans.

There are three main groups of tapeworms, each containing one or more species, that are a concern for most domestic animals and humans. Each group poses a different level of risk to people, and may be spread between animals and people in a different way.

The genus Dipylidium is most commonly found in domestic dogs, cats and is transmitted by swallowing an infected adult flea.

Flea control is essential for preventing infection in pets, because without adult fleas the parasite cannot be transmitted.

Remember that pets can be exposed to fleas from other animals if they go outside, even if they don’t become infested themselves. Do not allow pets to hunt or scavenge other animals. Keep cats indoors and prevent rodent infestations in the house. Keep dogs on a leash or at least in sight when outdoors.

Evolutionary relationships

One theory of human hairlessness is that the loss of hair helped humans to reduce their burden of fleas and other ectoparasites


Tapeworms

In contrast to fleas, tape worms are endoparasites, as they attach to other animals' guts to absorb nutrients from the food they eat. They live in the small intestines of many different species of animals, including humans.

There are three main groups of tapeworms, each containing one or more species, that are a concern for most domestic animals and humans. Each group poses a different level of risk to people, and may be spread between animals and people in a different way.

The genus Dipylidium is most commonly found in domestic dogs, cats and is transmitted by swallowing an infected adult flea.

Flea control is essential for preventing infection in pets, because without adult fleas the parasite cannot be transmitted.

Remember that pets can be exposed to fleas from other animals if they go outside, even if they don’t become infested themselves. Do not allow pets to hunt or scavenge other animals. Keep cats indoors and prevent rodent infestations in the house. Keep dogs on a leash or at least in sight when outdoors.