Life histories, diets, and secondary production of Odonata along a temperature gradient on the Copper River Delta, Alaska.

摘要

Dragonflies (Odonata: Epiprocta) and damselflies (Odonata: Zygoptera) are a conspicuous aspect of the biota in ponds on southcentral Alaska's Copper River Delta (CRD). Odonate densities, secondary production, and diets were assessed in sixteen ponds classified by delta region (east vs. west) and landscape type (outwash plain (OP) vs uplifted marsh (UM)).;Enallagma boreale (Coenagrionidae) comprised 48.5% of collected odonates. Leucorrhinia hudsonica (Libellulidae) and Aeshna juncea (Aeshnidae) comprised 36.6% and 10.4% of collected odonates, respectively. L. hudsonica densities and secondary production were significantly higher (p<0.001) in west UM ponds than in other pond types. Ostracods (Ostracoda) and water boatmen (Corixidae) dominated west OP A. juncea diets. Midge larvae (Chironomidae) dominated A. juncea diets in remaining pond types, occurring in 68% of foreguts. 27% of A. juncea foreguts demonstrated intraguild predation, and 6% of foreguts demonstrated cannibalism. Foreguts containing threespine stickleback (Gasterosteus aculeatus) revealed A. juncea's apex predator role in CRD ponds.