The fate of Australia's native bees in the face of climate change is a complex and urgent question. While many studies have focused on the relationship between heat tolerance and ambient temperatures, a new study published in Nature Communications takes a more nuanced approach by considering the microclimates that bees experience in their nests. The findings reveal a surprising twist: the most heat-tolerant bees are also the most vulnerable to future warming.
One of the key insights from this study is the importance of nest type in determining a bee's heat tolerance. Bees that nest in stems, which are exposed to the hottest temperatures, were found to be the most heat-tolerant. This makes sense, as these bees have no way to hide from the heat. In contrast, bees that nest in cavities, which provide a more buffered climate, were less heat-tolerant. Ground-nesting bees, which can hide from extreme heat, were the least heat-tolerant of all.
This finding has important implications for understanding how bees will respond to climate change. While the most heat-tolerant bees may be able to adapt to rising temperatures, they are also the most vulnerable to sudden changes in climate. This raises a deeper question: can bees evolve fast enough to keep pace with climate change?
The study also found that closely related species shared similar nesting strategies and heat tolerances. This suggests that evolutionary history plays a role in shaping heat tolerance. However, not all closely related bees shared the same nesting strategy, which makes it difficult to determine whether nesting strategy or heat tolerance came first. Nevertheless, the study provides valuable insights into the complex interplay between evolutionary history, nesting ecology, and heat tolerance.
One of the most striking findings from this study is the flip in vulnerability predictions when microclimate temperatures are considered instead of air temperatures. Using air temperatures, ground nesters were found to be the most vulnerable because they have the lowest tolerance to heat. However, when the microclimates species are exposed to in their nests were considered, stem nesters were shown to be the most vulnerable. This is because they are unable to hide from extreme temperatures, like ground nesters.
This finding has important implications for conservation efforts. Tropical Queensland, which still has one of the fastest land clearing rates on Earth, provides a cooler microclimate in an otherwise very warm environment. To conserve Australia's crucial pollinators, we need to stop further land clearing of tropical forests. As well as conserving native vegetation, Australia needs to slow its greenhouse gas emissions so we can secure pollination and food security into the future.
In conclusion, the fate of Australia's native bees in the face of climate change is a complex and urgent question. While the most heat-tolerant bees may be able to adapt to rising temperatures, they are also the most vulnerable to sudden changes in climate. This raises a deeper question: can bees evolve fast enough to keep pace with climate change? To answer this question, we need to continue researching the complex interplay between evolutionary history, nesting ecology, and heat tolerance, and take action to conserve our crucial pollinators.
