Oh, sorry. Below are the references:
Block, W., Webb, N. R., Coulson, S., Hodkinson, I. D. and Worland, M. R. (1994) Thermal adaptation in the collembolan Onychirurus arcticus. Journal of Insect Physiology. 40, 715-722.
Hodkinson, I. D., Coulson, S. J., Webb, N. R. and Block, W. (1996) Can high Arctic soil microarthropods survive elevated summer temperatures?. Functional Ecology. 10, 314-321.
Thanks for looking.