Social insects in Helsinki
This August I had the pleasure of attending the European IUSSI meeting on social insects, hosted by Lotta Sundström and colleagues at the University of Helsinki. The three-day scientific programme was highly diverse, with topics ranging from the evolution of eusociality to conservation and management practices surrounding social insects. A whole manner of social organisms were discussed including ants, bumblebees, honeybees, stingless bees, hornets, termites, spiders and even bacteria! Indeed, it was impossible not to find several exciting talks to attend each day.
The plenary speakers gave a great start to each day. Michel Chapuisat discussed supergenes and their role in the mating systems of ant colonies. Ashleigh Griffin then successfully took stock of her work on Pseudomonas bacteria in cystic fibrosis patients and co-operation in birds to suggest how co-operation breaks down within a population. Finally, Royal Holloway’s own Elli Leadbeater discussed learning in bees and proposed that simple associative learning can explain many ‘complex’ social behaviours. The results suggest that complex cognitive functions were not required to evolve to facilitate the transition to the social behaviour we see.
The decline in bee populations over the past few decades is thought to be the result of multiple stressors, including pathogens, habitat loss, and pesticides. These stressors were the subject of many talks including those from the Brown Lab. Our PhD student, Arran Folly, discussed his preliminary data that suggests that a compound in red clover nectar can enhance the resistance of bumblebees to the pathogen Nosema bombi. Other labs focused on the effect of pesticides: Liz Samuelson presented work suggesting that neonicotinoid thiamethoxam reduced bumblebee spatial working memory at field realistic doses, and therefore bees were likely to be less efficient foragers. Juliana Rangel then presented her work looking at the pesticide content of nectar and pollen across the US, which suggested that even in urban environments bees are exposed to pesticides, although these levels are not as high as in agricultural areas. Andres Arce also presented work concerning pesticides. His findings suggest that clothianidin reduces the number of workers, males and queens produced by bumblebee colonies in the field. Others focused on conservation aspects. Richard Gill presented a model of UK agriculture which could be used to predict where future agricultural development was likely to occur, which will help inform conservation efforts. I also discussed some of my PhD research, which investigated floral traits in the field bean, and suggests that floral traits could be optimized to provide better resources for bees when this mass flowering crop is grown.
Perhaps most interesting to us in the context of our work looking at disease transmission between bees when foraging were the talks on the viruses present in social insects. Dino McMahon discussed his recently published work looking at the closely related strains of Deformed Wing Virus (DWV): DWV-A and DWV-B, also known as simply DWV and Varroa Destructor Virus (VDV). DWV-B was demonstrated to be more virulent than DWV-A in lab experiments. In the field, it was also observed that co-infection with both strains was at a higher than expected level, suggesting the two strains interact. More generally, Rob Paxton gave an energising talk discussing the prevalence of many bee viruses across the world. He indicated that DWV was one of the most prevalent viruses in both solitary bees and bumblebees, followed by Black Queen Cell Virus (BQCV). As these viruses are also highly prevalent in honeybees, this adds further support to Matthias Fürst’s work, carried out whilst he was in our lab, which suggests that there is transfer of viruses between managed honeybees and wild bees in the field. Robyn Manley then followed up this topic, specifically looking at Slow Bee Paralysis Virus (SBPV), she found there was a prevalence of up to 80-90% in honeybees and bumblebees at some locations in the UK, although it was much lower at others. She also recorded SBPV in some solitary bee samples that she had collected. Lab work that she carried out suggested that under favourable conditions SBPV had no effect on bumblebee (Bombus terrestris) mortality, but under starvation conditions, bees were 1.6x more likely to die if they were infected with SBPV. Finally, Matthias Fürst presented some of his new work investigating the viruses found in different ant species. Examining the viral communities of three species of ant by determining the sequences present, and using then searching for the presence of a type of immune response (called small interfering RNA) to demonstrate the viruses were infective, his work suggested that the viral communities were not shared between different species sampled at the same site. This may mean that ant viruses are species specific and struggle to replicate outside of their normal hosts.
Overall, this was a great conference, not only for the fantastic research that was presented but also the people there. Social insect researchers are a friendly bunch and there were many stimulating conversations to be had, as well as a good dance, too!