R. Godoyherrera et Jl. Silva, LARVAL PREPUPATION BEHAVIOR OF DROSOPHILA-PAVANI, DROSOPHILA-GAUCHA AND THEIR RECIPROCAL HYBRIDS, Behaviour, 134, 1997, pp. 813-826
The behavioural mechanisms by which the larvae of the sibling species
D. pavani and D. gaucha, and their reciprocal hybrids select pupation
sites are described in terms of larval substrate preferences. If the l
arval behaviour of the parental species and their reciprocal hybrids d
uring pupation leads them to pupate in different substrates, such pref
erences could be used to identify environmental factors and genetic me
chanisms involved in the evolution of that behaviour. Confronted with
dry substrates, interspecific hybrid larvae pupated in the rearing cup
, while the parental species pupated both outside and inside the cup.
Like the parental species, the hybrids pupated outside, when humid sub
strates surrounded the rearing cup. Larvae from D. pavani and D. gauch
a showed a broader norm of reaction than the hybrids. D. pavani larvae
occupied dry and humid substrates to pupate, while D. gaucha larvae t
ended to prefer only humid substrates. Larvae of D. pavani burrowed in
to dry sand pupated preferently in the deep layers of the substrate. F
ew D. gaucha larvae burrowed; they tended to pupate in the upper layer
s of dry sand. D. pavani larvae pupated on the moist sand, while most
of D. gaucha larvae burrowed and formed puparia in the upper layers of
the substrate. The hybrid larvae showed no burrowing behaviour in eit
her dry or moist sand.