Bees even more under threat from climate change than we thought

12 Apr 2018

Image: kojihirano/Shutterstock

Bees are expected to face an even bleaker future as the effects of climate change ramp up in the years to come.

While it can be easy to pinpoint the direct threat posed by climate change to humans due to extreme fluctuations in weather, new research into its effect on bees shows that the insect is facing even greater danger than before.

In a paper published to Global Challenge Biology, a team of University of Exeter and University of Manchester researchers working with the UK Centre for Ecology and Hydrology found that drought roughly halved the overall number of flowers.

This has a dramatic knock-on effect on bees and other pollinators as it means less food from the flowers they need to survive.

Add to this the fact that bees are already under pressure from a variety of threats – including habitat loss, the use of particular pesticides, and the spread of diseases and alien species – and you start to see a grim picture being painted.

“Not only are these insects vital as pollinators of crops and wild plants, but they also provide food for many birds and mammals,” said joint lead researcher Dr Ros Shaw.

Unlike previous studies on the impact of drought on flowers, carried out by analysing individual species in a lab, the team used an experiment with rain shelters to examine the effects on real communities of plant species living in chalk grassland.

While the findings suggest that chalk grasslands may support lower pollinator populations in the future, the results are likely to be broadly applicable to other regions and habitats.

The returned data showed that the level of drought would be a rare event; however, the team added that, with climate change, such droughts are expected to become much more common.

Climate change and spread of disease

Speaking of insects, research conducted by Trinity College Dublin (TCD) towards the end of last month found that rising global temperatures as a result of climate change are likely to affect the severity of diseases from parasites such as mosquitos.

The team’s paper published to PLOS Biology demonstrated its proof of concept using the water flea (Daphnia magna) and its pathogen (Ordospora colligata) as a model system, using a longstanding biological concept known as the metabolic theory of ecology.

This helps to predict how a wide range of processes – all of which influence host-parasite dynamics – are affected by temperature.

The results showed that when applying a wide temperature range, different processes had unique relationships with temperature.

For example, while damage inflicted to the host per pathogen appeared to be independent of temperature, both host mortality and pathogen growth rate were strongly dependent – but in opposite ways.

“What is exciting is that these results demonstrate that linking and integrating metabolic theory within a mathematical model of host-pathogen interactions is effective in describing how and why disease interactions change with global warming,” said TCD professor Pepijn Luijckx of the research team.

Colm Gorey was a senior journalist with Silicon Republic