The life history of Zapada columbiana (Plecoptera: Nemouridae) in a Rocky Mountain stream

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The life cycle of Zapada columbiana (Claassen) is basically 3 years in a subalpine stream in the Rocky Mountains of Alberta, although some individuals may complete their life cycle in 2 years. Adults emerged from mid-April to early June and did not disperse far from the stream. Emerging adults and ovipositing females showed no tendency to move upstream. The eggs hatched prior to winter of the same year and growth of larvae was confined to the ice-free period of June to November. It was estimated that at any time during the growth season at least 50% of the population in the stream was in moss covering boulders and cobbles in riffles. Moss was the predominant component in guts of larvae taken from moss, and detritus predominated in guts of larvae from other habitats. During the winter, detritus (from conifer needles) was the major component of the gut contents. Experiments demonstrated that larvae grew faster on moss than on conditioned Salix glauca leaves. Larvae grew on conifer needles only when the latter were highly conditioned and fragmented. This study has indicated that Zapada columbiana, an abundant shredder in many Rocky Mountain subalpine creeks, is as dependent on the autochthonous production of moss as it is on allochthonous detritus.

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ELECTRONIC FILE - Zoology: Invertebrates

Citation: Mutch RA, Pritchard G. 1984. The life history of Zapada columbiana (Plecoptera: Nemouridae) in a Rocky Mountain stream. Canadian Journal of Zoology. 62(7):1273-1281. DOI: 10.1139/z84-184.