Pm. Hughes et al., ONTOGENY OF TRUE FLIGHT AND OTHER ASPECTS OF GROWTH IN THE BAT PIPISTRELLUS-PIPISTRELLUS, Journal of zoology, 236, 1995, pp. 291-318
We describe the ontogeny of pipistrelle bats Pipistrellus pipistrellus
Schreber (Chiroptera: Vespertilionidae), including for the first time
the development of true flapping flight. The study animals were born
to a group of 20 adults taken into captivity just before parturition,
and allowed free flight and association within a room designed to appr
oximate external conditions. All juveniles were aged to within one day
and individually marked. All adults were ringed. Comparison to wild s
tudies and the application of a set of growth models to forearm and bo
dy mass data gave no indication that development had been altered by c
aptivity. Forearm data were best fitted by the logistic growth model a
nd mass data by the 'Gompertz' growth model. Preliminary flight observ
ations were followed, once the bats had become truly volant, by experi
ments in a flight enclosure with stroboscopic stereophotogrammetry. As
the bats aged they used slower wingbeat frequencies (scaling with age
D as D--0.40), but flew faster, speed scaling with age as D-0.65. Win
gbeat amplitude did not alter significantly with age, nor did the tota
l mechanical power for flight, calculated by using a flight performanc
e model, although the cost of transport fell as the bats grew older. T
his was probably due to the improving efficiency of the wing; the deve
lopment of wingspan, wing area, wing loading, aspect ratio and tip are
a ratio are presented, and adaptations for reducing the energy require
ments during early flights are discussed. These included a mass recess
ion which occurred after the time of first flights. The flight model w
as also used to explore the hypothetical flight of bats with the morph
ology of neonates, and we discuss the extent of sexual dimorphism in t
he young bats and in their mothers.