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Invasive species may be more capable of adjusting to climate warming via phenotypic plasticity than native species since plasticity is thought to increase invasion success. Physiological plasticity via acclimation is one way in which organisms can adjust their thermal tolerance in response to temperature change, but few studies have addressed whether invasive species have greater thermal plasticity compared to native congeners. Here we investigated whether thermal plasticity via temperature acclimation varies between two Onthophagus dung beetle species, the non-native Onthophagus taurus and the native Onthophagus hecate, collected from both Florida and Tennessee, USA. We expected the non-native O. taurus to demonstrate greater plasticity than the native O. hecate; we also predicted that beetles from Florida would have reduced plasticity since their environment is less thermally variable. To examine thermal plasticity, we measured shifts in time until loss of function (i.e., leg mobility) following acclimation to hot or cold temperature treatments. We found that non-native O. taurus from Florida acclimated to warm temperatures, increasing time to loss of function following warm treatments; unexpectedly, O. taurus from Tennessee showed no warm acclimation ability. Onthophagus hecate did not acclimate to warm temperatures in either location. In contrast, both species showed similar levels of cold acclimation. Taken together, our results suggest that the non-native species, O. taurus, will be more capable of using physiological adjustments to respond to climate warming than the native species, O. hecate.
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Designing a Seasonal Acclimation Study Presents Challenges and Opportunities
Abstract Organisms living in seasonal environments often adjust physiological capacities and sensitivities in response to (or in anticipation of) environment shifts. Such physiological and morphological adjustments (“acclimation” and related terms) inspire opportunities to explore the mechanistic bases underlying these adjustments, to detect cues inducing adjustments, and to elucidate their ecological and evolutionary consequences. Seasonal adjustments (“seasonal acclimation”) can be detected either by measuring physiological capacities and sensitivities of organisms retrieved directly from nature (or outdoor enclosures) in different seasons or less directly by rearing and measuring organisms maintained in the laboratory under conditions that attempt to mimic or track natural ones. But mimicking natural conditions in the laboratory is challenging – doing so requires prior natural-history knowledge of ecologically relevant body temperature cycles, photoperiods, food rations, social environments, among other variables. We argue that traditional laboratory-based conditions usually fail to approximate natural seasonal conditions (temperature, photoperiod, food, ‘lockdown’). Consequently, whether the resulting acclimation shifts correctly approximate those in nature is uncertain, and sometimes is dubious. We argue that background natural history information provides opportunities to design acclimation protocols that are not only more ecologically relevant, but also serve as templates for testing the validity of traditional protocols. Finally, we suggest several best practices to help enhance ecological realism.
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- Award ID(s):
- 1951356
- PAR ID:
- 10325123
- Date Published:
- Journal Name:
- Integrative Organismal Biology
- ISSN:
- 2517-4843
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/iob/obac016
