MOSQUITOES OF MANITOBA: II. THE EFFECT OF STORAGE TEMPERATURE AND RELATIVE HUMIDITY ON HATCHING OF EGGS OF AEDES VEXANS AND AEDES ABSERRATUS (DIPTERA: CULICIDAE)

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Abstract
Optimum storage conditions for eggs of Aedes vexans (Meigen) were found to be a temperature of 2 °C and a saturated atmosphere. These conditions are also suitable for storing eggs of Aedes abserratus (Felt and Young) but this species can be stored at lower temperatures. When eggs of both species are stored at 2 °C and placed in a hatching medium at 2 °C, hatching begins in A. abserratus but not in A. vexans. A comparable hatch in the latter occurs at 10°–15 °C. Desiccation and death of A. vexans embryos occur rapidly at a low relative humidity (20%) and a high temperature (21 °C) but slowly at low relative humidity and a low temperature (4 °C). Eggs that lose a substantial amount of water will still hatch and the larvae develop normally, but hatching time is delayed. The hatching time may be twice as long as in eggs kept in a saturated atmosphere at similar temperatures, indicating that embryos must regain some of the lost water before hatching can occur.