Cat flea (Siphonaptera: Pulicidae) cocoon formation and development of naked flea pupae

The rate of cat flea, Ctenocephalides felis (Bouché), pupal development and the stimuli responsible for successful cocoon formation were investigated by rearing flea pupae without an enclosing cocoon. Female larvae pupated an average 12.1 h earlier than males, and female pupae developed to the adult stage an average 1.6 d earlier than males. When larvae were not allowed to orient against a perpendicular structure, only 2.2% of these larvae were able to spin an enclosing cocoon. Although these naked flea pupae had no enveloping cocoon, 96.5% survived to become adults. Gentle sifting of the larval medium 0-12 and 12-24 h after cocoons were formed resulted in 13.7 and 3.5% of the larvae emerging, respectively. Over 40% of those larvae did not spin a second cocoon, but developed as naked flea pupae.