Risk-spreading behaviour is often exhibited by animals as a response to unpredictably variable environments. Using field and laboratory studies, we tested the hypothesis that Sympetrum vicinum dragonflies spread the risks of winter environments by laying eggs across a terrestrial–aquatic gradient. Sympetrum vicinum eggs that overwintered in terrestrial and benthic-limnetic habitats had significantly higher hatching success compared with eggs that overwintered in littoral sites. Low success may have been caused by hypoxia due to excess sediment in the littoral samples in the lab. While hypoxia experienced under winter conditions (4°C) had no negative effect on hatching success, hatching in hypoxic and anoxic water significantly decreased hatching success. Opportunistic egg predation by a winter-active caddisfly significantly decreased egg hatching success. Because S. vicinum eggs have a relatively low supercooling point (− 26.25°C), freezing may not be a significant source of mortality in terrestrial or aquatic sites. By ovipositing in both terrestrial and aquatic environments, female dragonflies may be balancing the unpredictable risks of both the failure to inundate the eggs and egg predation. Our research highlights the potential for biotic interactions during winter to shape the behaviour and life-history of aquatic invertebrates.

See paper for description of data collection methods and analysis. Paper is available fully formated through the publisher or open access (unformatted) through the University of Toronto's T-Space. 

Notes explaing data are available in a README_.txt document. The same notes explaining data are available on each tab of the excel file. One extra tab of data is included here but was not used in our paper. Data uploaded here is raw unless otherwise indicated.