Net superoxide levels: steeper increase with activity in cooler female and hotter male lizards
Author
Summary, in English
Ectotherms increase their body temperature in response to ambient heat, thereby elevating their metabolic rate. An often inferred consequence of this is an overall upregulation of gene expression and energetic expenditure, and a concomitant increased production of reactive oxygen species (e.g. superoxide) and, perhaps, a shortened lifespan. However, recent work shows that this may be a superficial interpretation. For example, sometimes a reduced temperature may in fact trigger up-regulation of gene expression. We studied temperature and associated activity effects in male and female Australian painted dragon lizards (Ctenophorus pictus) by allowing the lizards to bask for 4 h versus 12 h, and scoring their associated activity (inactive versus active basking and foraging). As predicted, long-basking lizards (hereafter ‘hot’) showed heightened activity in both sexes, with a more pronounced effect in females. We then tested for sex-specific effects of basking treatment and activity levels on the increase in net levels of superoxide. In males, short-baskers (hereafter ‘cold’) had significantly more rapidly decreasing levels of superoxide per unit increasing activity than hot males. In females, however, superoxide levels increased faster with increasing activity in the cold than in the hot basking treatment, and females earlier in the ovarian cycle had lower superoxide levels than females closer to ovulation. In short, males and females differ in how their levels of reactive oxygen species change with temperature-triggered activity.
Department/s
Publishing year
2012
Language
English
Pages
731-735
Publication/Series
Journal of Experimental Biology
Volume
215
Issue
16
Full text
- Available as PDF - 235 kB
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Document type
Journal article
Publisher
The Company of Biologists Ltd
Topic
- Biological Sciences
Keywords
- reactive oxygen species
- thermoregulation
- lizard
Status
Published
Project
- Immunoecology
Research group
- Molecular Ecology and Evolution Lab
ISBN/ISSN/Other
- ISSN: 1477-9145