Following the crowd: fitness benefits of social behaviour

Lead Supervisor: Prof Tracey Chapman

Location: University of East Anglia, Biological Sciences

Duration: 6 weeks

Suitable undergraduate degrees: Biological Sciences, Ecology

Project background

Aim: The student will used a validated and ecologically relevant laboratory set up to test a major hypothesis for the evolution of social behaviour: namely the ‘selfish herd’ idea.

 Context: Responses to social environments can significantly alter reproductive investment. For example, recent research in fruitflies shows that individual females show striking plasticity in egg clustering. Females prefer to lay eggs with those of other females and dramatically increase egg clustering when substrates are firm and eggs are laid ‘on’ rather than ‘in’ substrates. The fitness benefits aren’t yet known. One key hypothesis, tested here, is that eggs are clustered to decrease predation. This represents a test of an important evolutionary theory: the ‘selfish herd’, in which clustering is favoured because it reduces the probability of individual predation.

Method: The student will used a validated and ecologically relevant laboratory set up, to test the hypothesis that females cluster their eggs to reduce the probability of egg predation by ants (which are known to feed upon fruitfly eggs). 12 colonies of Lasius niger ants (queens, with 20-30 workers) have already been established in the lab. The student will generate standardised substrates containing equal numbers of clustered vs non-clustered fruitfly eggs. These will then be placed into the ant arenas (6 arenas x 2 treatments) and the student will monitor predation events (time and frequency of predation events) 4 times for each colony over 2 weeks. Behaviour will be recorded using spot checks and digital filming (using a set up already established in house), with treatments anonymised for the student observer.

Results and analysis: The student will use R statistical programming to analyse spot check behavioural data to test whether the frequency or timing of predation events differs between treatments. They will also use behavioural analysis software to obtain rich temporal information on the duration of exploration behaviour and construct behavioural transition matrices.

Timetable:

• Week 1: induction, COSHH, risk assessments, general research training, experimental protocol, introduction to lab and mentors, weekly lab meeting and social event.
• Week 2: Prepare ant arenas and fruitfly laying substrates, collection of experimental fruitflies, tests of digital filming equipment.
• Week 3: creation of egg clustering test substrates, experimental set up and initiation of first week of data collection.
• Week 4: repeat of week 3.
• Week 5: data analysis training and execution.
• Week 6: write up and presentation to lab group meeting.

Significance: An important test of a fundamental evolutionary theory applied in a novel context. These data will be incorporated into a major publication on which it is anticipated the student would be an author.