Reprint of: The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper

Rebecca M B Harris; Peter McQuillan; Lesley Hughes

doi:10.1016/j.jtherbio.2015.10.008

Reprint of: The effectiveness of common thermo-regulatory behaviours in a cool temperate grasshopper

J Therm Biol. 2015 Dec:54:12-9. doi: 10.1016/j.jtherbio.2015.10.008. Epub 2015 Nov 14.

Authors

Rebecca M B Harris¹, Peter McQuillan², Lesley Hughes³

Affiliations

¹ Antarctic Climate Ecosystems CRC, University of Tasmania, Private Bag 80, Hobart, 7001, Australia. Electronic address: rmharris@utas.edu.au.
² School of Geography and Environmental Studies, University of Tasmania, Private Bag 78 Hobart, 7001, Australia.
³ Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia.

PMID: 26615722
DOI: 10.1016/j.jtherbio.2015.10.008

Abstract

Behavioural thermoregulation has the potential to alleviate the short-term impacts of climate change on some small ectotherms, without the need for changes to species distributions or genetic adaptation. We illustrate this by measuring the effect of behaviour in a cool temperate species of grasshopper (Phaulacridium vittatum) over a range of spatial and temporal scales in laboratory and natural field experiments. Microhabitat selection at the site scale was tested in free-ranging grasshoppers and related to changing thermal quality over a daily period. Artificial warming experiments were then used to measure the temperature at which common thermoregulatory behaviours are initiated and the subsequent reductions in body temperature. Behavioural means such as timing of activity, choice of substrates with optimum surface temperatures, shade seeking and postural adjustments (e.g. stilting, vertical orientation) were found to be highly effective at maintaining preferred body temperature. The maximum voluntarily tolerated temperature (MVT) was determined to be 44 °C ± 0.4 °C, indicating the upper bounds of thermal flexibility in this species. Behavioural thermoregulation effectively enables small ectotherms to regulate exposure to changing environmental temperatures and utilize the spatially and temporally heterogeneous environments they occupy. Species such as the wingless grasshopper, although adapted to cool temperate conditions, are likely to be well equipped to respond successfully to coarse scale climate change.

Keywords: Behaviour; Climate change; Orthoptera; Thermal tolerance.