Testing the beneficial acclimation hypothesis and its alternatives for locomotor performance

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• The beneficial acclimation hypothesis (BAH) suggests organisms adjust physiologically to improve performance in their environment.
• Recent research questions the BAH, with some studies showing a lack of support or confusing developmental plasticity with acclimation.

Purpose of the Study:

• To rigorously test the BAH in five related species of oribatid mites across marine to terrestrial habitats.
• To differentiate between beneficial acclimation, deleterious acclimation, and lack of plasticity.

Main Methods:

• Examined maximum speed, optimum temperature, and performance breadth across a temperature range (-10°C to 35°C).
• Exposed mites to four treatment temperatures (0°C, 5°C, 10°C, 15°C) to assess acclimation responses.
• Utilized a strong inference framework to analyze data from five congeneric ameronothroid oribatid mite species.

Main Results:

• One marine species showed weak beneficial acclimation.
• Two upper-shore/marine species displayed deleterious acclimation and supported the colder-is-better hypothesis.
• Two terrestrial species exhibited no plasticity, potentially due to low cue reliability or high plasticity costs.

Conclusions:

• Acclimation responses vary significantly among related species occupying different habitats.
• Lack of plasticity in terrestrial mites may be adaptive, but phylogenetic constraint is also a possibility.
• The BAH is not universally supported, with alternative hypotheses like deleterious acclimation and the colder-is-better hypothesis being relevant in certain contexts.