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Freeze tolerance of Cyphoderris monstrosa (Orthoptera: Prophalangopsidae)
Published online by Cambridge University Press: 06 June 2016
Abstract
The great grig, Cyphoderris monstrosa Uhler (Orthoptera: Prophalangopsidae), is a large (20–30 mm, >1 g), nocturnal ensiferan that inhabits montane coniferous forests in northwestern North America. Cyphoderris monstrosa overwinters as a late instar nymphs, but its cold tolerance strategy has not previously been reported. We collected nymphs from near Kamloops, British Columbia, Canada in late spring to determine their cold tolerance strategy. Cyphoderris monstrosa nymphs were active at low temperatures until they froze at −4.6±0.3 °C. The nymphs survived internal ice formation (i.e., are freeze tolerant), had a lethal temperature between −9 °C and −12 °C, and could survive for between five and 10 days at −6 °C. Isolated C. monstrosa gut, Malpighian tubules, and metafemur muscle tissues froze at temperatures similar to whole nymphs, and likely inoculate freezing in vivo. Hemolymph osmolality was 358±51 mOsm, with trehalose and proline comprising ~10% of that total. Glycerol was not detectable in hemolymph from field-fresh nymphs, but accumulated after freezing and thawing. The control of ice formation and presence of hemolymph cryoprotectants may contribute to C. monstrosa freeze tolerance and overwintering survival.
- Type
- Physiology, Biochemistry, Development, and Genetics
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- Copyright
- © Entomological Society of Canada 2016
Footnotes
Subject Editor: Hervé Colinet
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