The effect of temperature and photoperiod on larval development in Odonata
Enallagma boreale (Selys), a summer species, and Leucorrhinia glacialis (Hagen) and Libellula quadrimaculata (Linné), both spring species, were reared at various temperatures and photoperiods.E. boreale developed fastest at all temperatures, supporting my hypothesis that summer species have higher thermal coefficients for growth than spring species, but refuting my hypothesis that spring species grow faster at low temperatures.Photoperiod affected the development rate of L. glacialis and L. quadrimaculata at low temperatures, but did not affect E. boreal at any temperature, supporting my hypothesis that spring species are most likely to use photoperiod in regulating development. The striking growth-rate responses of the spring species to photoperiod at low temperatures suggest photoperiod is important in regulating development in temperate regions.