U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Impacts of temperature on metabolic rates of adult Extatosoma tiaratum reared on different host plant species

Sarah J. Hill, Sarah C. Silcocks, Nigel R. Andrew
Physiological entomology 2020 v.45 no.1 pp. 7-15
Eucalyptus, Extatosoma tiaratum, Rubus plicatus, adulthood, diet, egg production, fecundity, females, host plants, imagos, insects, landscapes, leaves, longevity, males, metabolism, rearing, temperature, thermal stress
Access to balanced nutrition enables optimum health and development, body repair, fat storage, increased fecundity and longevity. In the present study, we assessed the responses of a generalist leaf feeder (the phasmid Extatosoma tiaratum) reared continuously on one of three host plants, tree lucerne (Chamaecyisus palmensis), bramble (Rubus fruticosus) and Eucalyptus species, in a low fluctuating temperature environment until adulthood. Once all individuals reached adulthood, we exposed each individual to a ramping temperature event (starting at 25 °C and ramping the temperature at 0.25 °C min⁻¹) and assessed their metabolic rates (V˙CO2) responses at specific temperature 'bins' (25, 30, 35, 40 and 42 °C). Sex but not diet influenced respiration and metabolic rate. Male individuals, on average, had a higher V˙CO2 than females. Sex and diet were significant influences on V˙CO2 at different temperatures. Metabolic rates at lower temperatures were not affected by sex or diet type. At 35 °C, metabolic rates were influenced by sex and diet, with males reared on bramble and tree lucerne having a higher metabolic rate than females reared on the same foodplant, whereas Eucalypt reared animals showing an opposite trend. Lifetime egg production by females was 150% higher on bramble compared with the other host plants. Incorporating fluctuating temperature ranges into experiments will further help to understand the impact that thermal stress will have on the growth, development, performance and survival of insects in a more variable climatic and nutritional landscape.