Fleas
Fleas are insects belonging to the order Siphonaptera. The adults are wingless and have enlarged hind legs that enable them to leap long distances. Their tough bodies are 2-5mm long, brownish black in colour and laterally compressed. This gives them a very slim shape and is an adaptation that enables them to move easily through the fur or feathers of their host animals. The larvae are white legless slender maggots. Fleas are very advanced endopterygote insects, related to the scorpionflies and true flies.
Species in Britain and Ireland
There more than 60 species of flea in Britain and Ireland. Most are parasites of mammals but about a quarter occur on birds. The species most frequently encountered in Britain is the cat flea, Ctenocephalides felis, which also occurs on dogs. Other common fleas of garden mammals are the hedgehog flea Archaeopsylla erinacei and those associated with squirrels, mice and voles. Bird nest boxes often contain large numbers of bird fleas of various species. The animal with the misfortune of harbouring Britain’s largest flea, Hystrichopsylla talpae, is the mole.
Biology
Adult fleas feed by sucking blood from birds and mammals. They are particularly associated with animals that make nests or have other places that they habitually occupy. Fleas are often very host-specific so that for example the hedgehog flea cannot survive on cats and dogs. Flea larvae are scavengers that feed on detritus in the nests of their host animals. They also eat the remains of blood meals that have been voided by adult fleas.
Life cycle
Fleas lay their eggs in the nest material of their host animals. The larvae do not suck blood but feed on debris material in the nest. When fully fed, the larva spins a silk cocoon and pupates within. Adult fleas can remain inactive inside their cocoons until they are stimulated to emerge by vibrations that indicate the approach of a host animal. Bird fleas generally have one generation a year and overwinter as pupae in bird nests. Adults emerge in spring and cluster around the nest or bird box, hoping to find a suitable bird they can transfer on to. Mammal fleas may have several generations a year.
Role of fleas in gardens
Fleas can make like uncomfortable for those birds and mammals that are prone to infestation. In addition to the irritation caused by the bites of blood-sucking adults, fleas can spread diseases. These include myxomatosis in rabbits, which is spread by the rabbit flea, Spilopsyllus cuniculi.
The dog flea, Ctenocephalides canis, is a host for part of the life cycle of the dog tapeworm, with the cat flea having a similar role for the common cat tapeworm. Tapeworm eggs are passed out of the mammal host’s gut. These eggs are ingested by flea larvae, with the next stage in the tapeworm’s life cycle taking place within the flea’s body. Cats pick up tapeworms when they swallow fleas while grooming themselves.
Fleas can lurk in grass and garden leaf litter, and can reinfest pets from these sources after they have been treated. Proprietary biological controls in the form of nematodes can be found on the internet under "Lawn flea Nematodes"
Other sources of information
Books
Whitaker, A. P. (2007) Handbooks for the Identification of British Insects Vol 1 part 16. Fleas (Siphonaptera). Royal Entomological Society
Page text drafted by Andrew Halstead, reviewed by Andrew Salisbury, compiled by Steve Head
Cat flea Ctenocephalides felis. Left: Adult Above: eggs (against a scale of millimetres).
Below Left: Pupa in cocoon (arrow points to shed larval skin) Right: Larva.
Fleas
Fleas are insects belonging to the order Siphonaptera. The adults are wingless and have enlarged hind legs that enable them to leap long distances. Their tough bodies are 2-5mm long, brownish black in colour and laterally compressed. This gives them a very slim shape and is an adaptation that enables them to move easily through the fur or feathers of their host animals. The larvae are white legless slender maggots. Fleas are very advanced endopterygote insects, related to the scorpionflies and true flies.
Species in Britain and Ireland
There more than 60 species of flea in Britain and Ireland. Most are parasites of mammals but about a quarter occur on birds. The species most frequently encountered in Britain is the cat flea, Ctenocephalides felis, which also occurs on dogs. Other common fleas of garden mammals are the hedgehog flea Archaeopsylla erinacei and those associated with squirrels, mice and voles. Bird nest boxes often contain large numbers of bird fleas of various species. The animal with the misfortune of harbouring Britain’s largest flea, Hystrichopsylla talpae, is the mole.
Cat flea Ctenocephalides felis. Above Left: Adult Right: eggs (against a scale of millimetres).
Below Left: Pupa in cocoon (arrow points to shed larval skin) Right: Larva.
Biology
Adult fleas feed by sucking blood from birds and mammals. They are particularly associated with animals that make nests or have other places that they habitually occupy. Fleas are often very host-specific so that for example the hedgehog flea cannot survive on cats and dogs. Flea larvae are scavengers that feed on detritus in the nests of their host animals. They also eat the remains of blood meals that have been voided by adult fleas.
Life cycle
Fleas lay their eggs in the nest material of their host animals. The larvae do not suck blood but feed on debris material in the nest. When fully fed, the larva spins a silk cocoon and pupates within. Adult fleas can remain inactive inside their cocoons until they are stimulated to emerge by vibrations that indicate the approach of a host animal. Bird fleas generally have one generation a year and overwinter as pupae in bird nests. Adults emerge in spring and cluster around the nest or bird box, hoping to find a suitable bird they can transfer on to. Mammal fleas may have several generations a year.
Role of fleas in gardens
Fleas can make like uncomfortable for those birds and mammals that are prone to infestation. In addition to the irritation caused by the bites of blood-sucking adults, fleas can spread diseases. These include myxomatosis in rabbits, which is spread by the rabbit flea, Spilopsyllus cuniculi.
The dog flea, Ctenocephalides canis, is a host for part of the life cycle of the dog tapeworm, with the cat flea having a similar role for the common cat tapeworm. Tapeworm eggs are passed out of the mammal host’s gut. These eggs are ingested by flea larvae, with the next stage in the tapeworm’s life cycle taking place within the flea’s body. Cats pick up tapeworms when they swallow fleas while grooming themselves.
Fleas can lurk in grass and garden leaf litter, and can reinfest pets from these sources after they have been treated. Proprietary biological controls in the form of nematodes can be found on the internet under "Lawn flea Nematodes"
Other sources of information
Books
Whitaker, A. P. (2007) Handbooks for the Identification of British Insects Vol 1 part 16. Fleas (Siphonaptera). Royal Entomological Society
Page text drafted by Andrew Halstead, reviewed by Andrew Salisbury, compiled by Steve Head
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