Rapid bluing and slow browning: reversible body color change according to ambient temperature in damselfly Indolestes peregrinus (Ris, 1916)

Variation in body color occurs in many animals, and its function differs by species. Some species use multiple colors to create different effects. Most dragonflies change their body color unilaterally with maturation, whereas in a few species these changes are reversible. Both sexes of the damselfly Indolestes peregrinus show temperature-dependent reversible body color changes, with a brown color when the ambient temperature decreases and a blue color when the temperature increases. To elucidate the temperature range at which this color change occurs and the exact elapsed time for the color change, laboratory experiments were conducted to determine whether the time required for body color change was related to ambient temperature and whether sex differences affected this duration. The body color and time required for the change were recorded under four temperature conditions. Bluing was completed in a few minutes, whereas browning took several hours. Moreover, sexual differences were observed, whereby males showed a more rapid transformation to blue than that of females. Our results suggest that the rapid bluing has some importance in this species, especially in males.