Developmental Cycle of Fleas
The flea develops via a number of stages, beginning with the egg, followed by the larva, pupa and finally adult stage. The life cycle of the flea is one of complete metamorphosis. It can be completed in as little as 14 days or be prolonged up to 140 days,
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Developmental Cycle of Fleas
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The flea develops via a number of stages, beginning with the egg, followed by the larva, pupa and finally adult stage. The life cycle of the flea is one of complete metamorphosis. It can be completed in as little as 14 days or be prolonged up to 140 days, depending mainly on temperature and humidity (Silverman et al. 1981b). The life cycle of most flea species is characterized by three events: the hatching of the egg, the period from 1st instar to pupa, and the period from pupa to adult (Linardi et al. 1997) (Fig. 5).
Fig. 5. Life cycle of the cat and dog flea (j)Adult female flea @ Eggs @ Larva ® Pupa ® Preemerged adult
F. Krämer et al., Flea Biology and Control © Springer-Verlag Berlin Heidelberg 2001
Chapter 5 Developmental Cycle of Fleas
Eggs Cat flea eggs possess a widely oval form, rounded at both ends, a slightly transparent color at the beginning, later a pearly white color, 0.5 x 0.3 mm size, a smooth surface which can slightly darken later on (Karandikar and Munshi 1950), and they are well visible to the naked eye (Fig. 6). They are laid nearly exclusively on the host by mature females and do not immediately fall from the animal after they are positioned, according to Rust and Dryden (1997). Initially the chorion of the egg is wet, which tends to prevent drop-off. But it dries rapidly and 60% of the eggs drop off within two hours of deposition (Rust 1992). The rate at which eggs drop or are dislodged from the pelage is influenced by grooming, hair coat length, and host activity (Rust and Dryden 1997). Within eight hours about 70% of them are dislodged from the host (Rust 1992). Temporal patterns of egg deposition are reported with a correlation between peak egg production and periods of the cat sleeping or resting at the middle of scotophase. Significantly fewer eggs are produced near dusk and dawn (Kern et al. 1992). Rust (1992) reported similar results of peak egg production during the last eight hours of scotophase, but no correlation between peak egg production and resting or sleeping patterns in test cats. Furthermore fleas did not change their egg production in response to different photoperiods (Metzger and Rust 1996). Dropping off the host, flea eggs accumulate in areas where pets sleep and rest (Byron 1987). Egg deposition by adult females does not take place during the first 24 hours of blood feeding and is only less than half of the daily average during the second 24 hour period (Thomas et al. 1996). Further a low average fecundity was recorded during the first three days (Thomas et al. 1996). The start of the egg production is also influenced by the age of the female flea: Osbrink and Rust (1984) reported of 4-dayold adult females placed on a host, beginning egg production after two days, whereas adult females younger than 24 hours require three to four days on the host before egg production starts (Osbrink and Rust 1985b). On cats, fleas reach reproductive maturity within the first week, with a peak of egg output occurring sometimes as quickly as within t
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