A recent study published in Nature Communications has assessed the heat tolerance of 95 native bee species in eastern mainland Australia. The findings reveal a stark difference in climate vulnerability based on nesting behavior.
The Key Finding
Bees that nest in plant stems have a lower capacity to escape extreme temperatures compared to ground-nesting bees, making them more vulnerable to climate change in the near term.
Nesting Styles and Risk
Researchers categorized bee nesting behaviors into three distinct types: ground burrows, wood cavities, and plant stems. The data shows a clear hierarchy of risk.
- Ground-nesting bees can "hide from extreme heat" by retreating deeper into the soil.
- Stem-nesting bees experience higher temperatures due to the limited insulation provided by their chosen habitat.
This means stem-nesting species appear to have the lowest capacity to escape unfavourable environmental temperatures.
Broader Implications
The study, a collaboration between Macquarie University, The University of Sydney, La Trobe University, Flinders University, University of Wollongong, Adelaide University, and The University of Queensland, also highlighted a geographic pattern.
Tropical bees showed increasing vulnerability to climate change closer to the equator.
Interestingly, bees with the highest heat tolerance are not necessarily the safest. Many of these species already live in hot environments and may have limited ability to adapt further.
Why Native Bees Matter
Australia is home to approximately 1,700 native bee species. These insects are critical pollinators for both natural ecosystems and key crops, including macadamia nuts, avocados, mangos, and lychees.
Expert Perspectives
Dr. Carmen da Silva (Macquarie University): "Bees that nest underground can hide from extreme heat... Stem-nesting species appear to have the lowest capacity to escape unfavourable environmental temperatures. "
Dr. Vanessa Kellermann (La Trobe University): "Predicting which species will be vulnerable to climate change is one of the biggest challenges in ecology. "
Dr. Ros Gloag (University of Sydney): "This study helps us recognise that having a better understanding of native bee behaviour is key to identifying the greatest threats to their wild populations. "