Observation et analyse de la prédation des œufs d'Ambystoma maculatum (Shaw) (Amphibia, Urodela) par des larves de Diptères chironomidés, dans la région de Trois-Rivières (Québec)

Abstract

Observations during spring 1980 in two temporary pools near Trois-Rivières, Quebec, and in the laboratory show that Dipterian chironomid larvae can go through the gelatinous envelopes of egg masses of the salamander Ambystoma maculatum and consume developing eggs and embryos. In the clear water pool, egg spawns are heavily infested by the chironomid Parachironomus cf. forceps and embryonic mortality reaches 70 to 100%. In the dark water pool, infestation by an unidentified chironomid is low and embryonic mortality reaches 8%. In both cases, chironomid larvae leave the egg masses some 9 days before hatching of the salamanders. Fortuitous exploitation of a readily available resource is hypothesized; the frequency and precision of the observed phenological coincidence, due to the presence of other syntopic amphibian spring breeders, will be examined further.