Learning to communicate: How do pheromones work in social and solitary bees and how did they evolve?

This Project has been filled

Project description

Honeybees, bumblebees and other bee species are facing a multitude of threats from disease, pesticide exposure and loss of habitat. These threats have resulted in alarming declines in bee numbers, which is a concern for biodiversity and conservation. Additionally, these threats are also increasing the difficulty and costs associated with commercial honeybee keeping.

Probably the best known and arguably the most economically important bee species is the honeybee, Apis mellifera. This species and the bumblebee are the most extensively managed pollinator species globally and much research on bees has focussed on these two species. These bees are both ‘eusocial’ – they live in colonies with hundreds to thousands of individuals. In each colony, there is only one reproductively active female who is responsible for the majority of reproduction and workers carry out most other colony tasks.

However, the UK is also home to 250 species of solitary bees, which are comparatively under-studied. Solitary bees spend the majority of their lives on their own, only getting together to mate, and individual females forage, lay eggs and collect provisions for their offspring (e.g. the red mason bee).

The transition between solitary to eusocial living has occurred multiple times in bees and is one of the major and most successful life history transitions in animal evolution. This transition has required the elaboration of complex methods of communication between individuals within a species, and in most eusocial insects this complex communication is carried out using pheromones. Pheromones are not only central to the function of social bee colonies but also for mating and other intra-species communication in solitary bees.

Understanding how these transitions occurred addresses a major question in evolutionary biology, but also has practical importance for the management of these important species.

My research to date has been primarily focussed on understanding how worker bees respond to queen mandibular pheromone (e.g. [1]) and how the response to QMP may have evolved [2]. But the pheromones found in honeybees are markedly different to bumblebees and also to solitary bees – how did they evolve?

The exact nature of this project will be determined in collaboration with the successful student. Broadly, this project will use lab-and field-based studies combined with behavioural ecology and molecular approaches to understand how these mechanisms of communication work, how they evolved and if/how pheromones are affected by environmental exposures like pesticides or pathogens. This project will use solitary bees (e.g. the red mason bee Osmia bicornis), primitively eusocial species, and social bees like honeybees and bumblebees to address these questions.

Understanding pheromone communication has immense practical importance; in the honeybee, there is substantial overlap in the behaviours modulated by pheromones in the hive and the sub-lethal effects of pesticides e.g. foraging activity, sucrose sensitivity and reproduction. Much of the ecotoxicological testing that is used to determine safe levels of chemical exposure for bees are done so in honeybees in a laboratory environment. These assays are generally done in the absence of these pheromones that are so key to communication in bee species, raising the questions of whether i) pheromone production is affected by these compounds or ii) whether pheromones are able to potentiate or mitigate the toxicity of environmental contaminants. This project will address these questions using a combination of laboratory and field studies to determine if pheromone communication is disrupted or affected by environmental influences, like climate change and/or pesticide exposures in solitary and social bees.

This project directly addresses a key question in evolutionary biology but also has practical importance. The honeybee is intensively managed for pollination of crops contributing £651 million to the British economy annually and is incredibly important for the security of our food supply. Understanding how to control pest species without harming beneficial insects, like pollinator species, is of paramount importance. Understanding more about how social insects and solitary bees function will assist with these goals. Ultimately it is hoped that this knowledge about the fundamental biology of these important insects will also help inform conservation efforts aimed at maintaining bee biodiversity in the UK and globally.

For details please contact Dr Elizabeth Duncan (e.j.duncan@leeds.ac.uk)

 

Expected outcomes

This project is using molecular and ecological tools to address fundamental questions about animal communication, evolution and adaptation. This project will also have practical importance by determining if pheromones affect/or are affected by environmental exposures like pathogens and pesticides. The project will produce several publishable papers, the work will be presented and international conferences and the questions being addressed are of wide scientific interest and has practical importance especially with regards to ecotoxicological testing.

Requirements

A strong undergraduate (and ideally Masters) degree in ecology, genetics, biology or zoology is expected. However, training will be provided in all techniques relevant to the project. If you are not sure if you have the relevant background please feel free to contact the supervisors to discuss the project.

Training

This project will provide students with a broad range of training in a range of techniques associated with phenotypic measurements, life history measurements, behavioural assays and molecular/genetic analysis. The work blends behavioural ecology with genetics, providing a broad foundation for a future career. The PhD student will have access to a range of training courses designed to facilitate skills development and will be expected to present the outcomes of this project at both national and international conferences.

Research context and partners

Dr Duncan, Dr Bretman (Leeds) and Dr Gilbert (Hull) all have active research groups and strong records of relevant research: in molecular mechanisms of environmental responsiveness, animal behaviour and evolutionary ecology respectively. The student will be involved in fortnightly team meetings, as well as having access to both formal (Faculty) and informal (Ecology & Evolution group) seminar series through the School of Biology. There will be significant interactions between the Duncan, Bretman and Gilbert laboratories, ensuring that the PhD student graduates with a broad view of not only their field but also the wider fields of evolution, development and ecology. Co-supervision will involve meetings between all participants and the co-supervisors will provide guidance on the overall direction of the project.

References

[1] Duncan et al., (2016) “Notch signalling mediates reproductive constraint in the adult worker honeybee” Nature Communications 7, 12427.

[2] Lovegrove et al., (in press) “Ancestral hymenopteran queen pheromones do not share the broad phylogenetic repressive effects of honeybee queen mandibular pheromone” J. Insect Physiol