Summary: Belg. J. Zool., 133 (2) : 95-102 July 2003
Trophic habits and aquatic microhabitat use in gilled
immature, paedomorphic and metamorphic Alpine newts
(Triturus alpestris apuanus) in a pond in central Italy
Mathieu Denoël1 and Franco Andreone2
1 Laboratory of Fish and Amphibian Ethology, Behavioural Biology Unit, Department of Life Sciences, University of Liège,
22 Quai Van Beneden, B­4020 Liège, Belgium
2 Sezione di Zoologia, Museo Regionale di Scienze Naturali, Via G. Giolitti 36, I­10123 Torino, Italy
Corresponding author : M. Denoël, e-mail : Mathieu.Denoel@ulg.ac.be
ABSTRACT. Current evolutionary models suggest that the presence of heterogeneous habitats favours the evolu-
tion of polymorphisms. In such cases, alternative phenotypes can coexist because they use different resources. Fac-
ultative paedomorphosis is a heterochronic polymorphism in which a morph ­ the paedomorph ­ retains larval traits
during the adult stage while the other morph ­ the metamorph ­ is fully metamorphosed. The aim of this study was
to determine the microhabitat use and the diet of Alpine newt paedomorphs, metamorphs and immatures (Triturus
alpestris apuanus) coexisting in a small pond in Tuscany, central Italy, i.e. in a habitat where dimorphism is not
expected. Although the two adult morphs do not use exactly the same resources, resource partitioning was weaker
than in deep Alpine lakes. Nevertheless, the diet of immature gilled newts (larvae) differed from that of adults (met-
amorphs and paedomorphs). While the larvae eat a large number of planktonic organisms, the adults focus on insect
larvae and newt eggs. The differences in resource use favour the coexistence of aquatic juveniles and adults. In the
studied pond, facultative paedomorphosis was previously shown to be favoured by a precocious maturity of the

Source: Andreone, Franco - Zoology Department, Museo Regionale di Scienze Naturali di Torino

Collections: Biology and Medicine; Environmental Sciences and Ecology