- Fleas are wingless insects (1.5 to 3.3 mm) long) that are agile, usually dark coloured (for example, the reddish-brown of the cat flea), with tube-like mouth-parts adapted to feeding on the blood of their hosts.
- Their legs are long, the hind pair well adapted for jumping: a flea can jump vertically up to (18 cm) and horizontally up to (33 cm),making the flea one of the best jumpers of all known animals (relative to body size).
- If humans had the jumping power of a flea, a 1.8 m person could make a jump 90 m long and 49 m high.
Life cycle and habitat
- Fleas are holometabolous insects, going through the four life cycle stages of egg, larva, pupa, and imago.
- Adult fleas must feed on blood before they can become capable of reproduction.
- Fleas populations are evenly distributed, with about 50% eggs, 35% larvae, 10% pupae, and 5% adults.
- The flea life cycle begins when the female lays after feeding.
- Eggs are laid in batches of up to 20 or so, usually on the host itself, which means that the eggs can easily roll onto the ground.
- Because of this, areas where the host rests and sleeps become one of the primary habitats of eggs and developing fleas.
- The eggs take around two days to two weeks to hatch.
- Flea larvae emerge from the eggs to feed on any available organic material such as dead insects, faeces, and vegetable matter.
- Blood only diets allow only 12% of larvae to mature, whereas blood and yeast or dog chow diets allow almost all larvae to mature
- . They are blind and avoid sunlight, keeping to dark places like sand, cracks and crevices, and bedding.
- Given an adequate supply of food, larvae will pupate and weave silken cocoons within 1–2 weeks after 3 larval stages.
- After another week or two, the adult fleas are fully developed and ready to emerge.
- They may remain resting during this period until they receive a signal that a host is near – vibrations (including sound), heat, and carbon dioxide are all stimuli indicating the probable presence of a host.
- Fleas are known to overwinter in the larval or pupal stages.
- Once the flea reaches adulthood, its primary goal is to find blood and then to reproduce.
- Its total life span can be as short as one year, but may be several years in ideal conditions.
- Female fleas can lay 5000 or more eggs over their life, allowing for phenomenal growth rates. Average 30–90 days.
- A flea might live a year and a half under ideal conditions.
- These include the right temperature, food supply, and humidity.
- Generally speaking, an adult flea only lives for 2 or 3 months. Without a host for food a flea’s life might be as short as a few days.
- With ample food supply, the adult flea will often live up to 100 days.
- Newly emerged adult fleas live only about one week if a blood meal is not obtained. However, completely developed adult fleas can live for several months without eating, so long as they do not emerge from their puparia.
- Optimum temperatures for the flea’s life cycle are 21 °C to 30 °C and optimum humidity is 70%.
- Adult female rabbit fleas, Spilopsyllus cuniculi, can detect the changing levels of cortisol and corticosterone hormones in the rabbit’s blood that indicate it is getting close to giving birth.
- This triggers sexual maturity in the fleas and they start producing eggs.
- As soon as the baby rabbits are born, the fleas make their way down to them and once on board they start feeding, mating, and laying eggs.
- After 12 days, the adult fleas make their way back to the mother.
- They complete this mini-migration every time she gives birth.
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