Mutualism meltdown in insects: bacteria constrain thermal adaptation

Area of Science:

• Ecology and Evolutionary Biology
• Microbial Symbiosis
• Climate Change Adaptation

Background:

• Organismal adaptation to climate change hinges on abiotic and biotic interactions.
• Bacterial symbionts in insects serve as crucial models for understanding adaptation.
• While some symbionts enhance plasticity, obligate insect mutualists face constraints like genome deterioration and thermal sensitivity.

Purpose of the Study:

• To investigate how bacterial symbionts influence insect adaptation to changing environments.
• To assess the role of thermal sensitivity in bacterial mutualists as a constraint on insect climate change responses.

Main Methods:

• Analysis of existing field-based studies on insect-microbe interactions and thermal stress.
• Comparative assessment of symbiont roles in facilitating versus constraining adaptation.
• Examination of thermal sensitivity in obligate bacterial mutualists.

Main Results:

• Obligate bacterial mutualists exhibit vulnerability to high temperatures, similar to coral bleaching.
• Thermal sensitivity of these bacterial partners directly constrains insect responses to warming.
• Highly dependent mutualisms represent a critical vulnerability for insect thermal tolerance.

Conclusions:

• The thermal sensitivity of essential bacterial symbionts can act as an 'Achilles' heel' for insect adaptation to climate change.
• Understanding these microbial partnerships is vital for predicting species' responses to global warming.
• Conservation strategies may need to consider the thermal tolerance of both insects and their symbiotic partners.