Biology Publications

Document Type

Article

Publication Date

Winter 12-2016

Journal

The Canadian Entomologist

Volume

148

Issue

6

First Page

668

Last Page

672

URL with Digital Object Identifier

https://doi.org/10.4039/tce.2016.21

Abstract

The great grig, Cyphoderris monstrosa Uhler (Orthoptera: Prophalangopsidae), is a large (20-30 mm, >1 g), nocturnal ensiferan that in habits montane coniferous forests in northwestern North America. C. monstrosa overwinters as a late-instar nymph, but its cold tolerance strategy has not previously been reported. We collected nymphs from near Kamloops, British Columbia, in late spring to determine their cold tolerance strategy. C. 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 and -12 °C, and could survive for between five and ten days at -6 °C. Isolated C. monstrosa gut, Malpighian tubules and hind femur 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 approximately 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.

Notes

Submission must include acknowledgment and a link to the publisher's version (doi: https://doi.org/10.4039/tce.2016.21)

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