The adaptive value of learning in different ecological contexts
Despite a large amount of research into the mechanisms of learning we still know almost nothing about how cognitive traits might be adapted to different ecological conditions. This project provides a series of novel experimental approaches to address this issue. Anticipated environmental change is almost certain to affect the structure and dynamics of pollination systems. A more complete understanding of pollinator behaviour means we will be better able to predict how the pollination of crops and wild flowers will be affected by environmental change.
Learning, or the adaptive modification of behaviour based on experience, is an important way in which animals can respond to changes in their environment. Many pollinators are actually faced with a complex environment in which to collect food – this ‘pollination market’ may contain dozens of flower types which not only vary in colour, shape and scent, but also in the quantity and quality of rewards (principally pollen and nectar) they present. The rewards on offer may change very rapidly over the course of the day depending on the timing of reward provision by flowers, climatic conditions and the activity patterns of other flower visitors. Hence, learning to modify flower choices rapidly could be advantageous to a pollinator in circumstances where the floral market is highly dynamic. This view is supported by current data showing that colonies containing faster learning individuals are more efficient at collecting nectar in the field (Raine & Chittka 2008). However, there is actually a large range in learning performance among bee colonies with individuals in some colonies learning much faster than others. Therefore, a key question is what maintains this variability in cognitive abilities if faster learning performance appears to be at a selective advantage?
This project will investigate these questions using the bumblebee (Bombus terrestris) as a model system in both laboratory and field experiments. Previous work has shown that B. terrestris colonies are amenable to laboratory learning experiments and that the same colonies can subsequently be moved into the field to assess their foraging abilities (an established robust proxy measure of colony fitness) under ecologically relevant conditions (Raine & Chittka 2007; 2008). This approach enables us to examine potential links between cognitive abilities (tested in the laboratory) with foraging performance (assessed under field conditions). B. terrestris is an important pollinator species which is bred commercially for large-scale crop pollination. In the laboratory several generations of bees can be raised each year and this will form the basis of selection experiment to examine the heritability of learning performance. ‘Fast’ and ‘slow’ learning lines of bumblebee colonies will be selectively bred from the most extreme behavioural phenotypes observed in each generation. The foraging performance of these colonies will then be tested in a range of habitats to assess the ecological conditions to which particular cognitive behavioural phenotypes might be best adapted.
This project will also examine how variation in learning performance between isolated B. terrestris populations could be adapted to particular local floras. B. terrestris occurs throughout Europe including many isolated island populations. Preliminary data indicate a number of striking differences in learning ability between colonies tested from several isolated populations. This project will investigate whether these differences are predictably linked to differences in local flora in which they each forage, particularly with respect to the degree to which the most profitable flower species changes over time (a trait which could favour faster learning).
For further details about the project please contact Dr. Nigel Raine (nigel.raine@rhul.ac.uk).
Applications should be made by submitting a completed application form (available from http://www.rhul.ac.uk/BioSci/Vacancies/SBSPhD2010.doc) and a full CV by email to BioSciencesTemp@rhul.ac.uk by 20th March. Candidates should arrange for two academic references to be sent to the same email address (BioSciencesTemp@rhul.ac.uk) by the same date. It is anticipated that interviews will take place in April.
References
Raine NE, L Chittka (2007). The adaptive significance of sensory bias in a foraging context: floral colour preferences in the bumblebee Bombus terrestris. PLoS One 2: e556.
Raine NE, L Chittka (2008). The correlation of learning speed and natural foraging success in bumble-bees. Proceedings of the Royal Society of London Series B 275: 803-808.
NB: pdf versions of these papers can be downloaded from: http://www.biology.qmul.ac.uk/research/staff/chittka/chittkalab/Team/Nigel.html
Dr. Nigel Raine
Senior Lecturer in Behavioural Ecology,
School of Biological Sciences,
Royal Holloway, University of London,
Egham, Surrey,
TW20 OEX.
Tel: ++44 (0)1784 443539
Web: http://www.biology.qmul.ac.uk/research/staff/chittka/chittkalab/Team/Nigel.html