PhD Studentship at University of Portsmouth, UK.

(Sorry, only UK and European (EU/EEA) candidates)

The Ecology of Honesty: Evolution of Plant-Insect Signalling in
Dalechampia vines.

Applications are invited for competition-funded PhD Studentship in the
School of Biological Sciences at the University of Portsmouth.
Portsmouth, UK, commencing on the 1st October 2011. (Stipend ca.
13,000 pounds per year, 3 years)

The evolution of signalling systems that determine the ecology and
evolution of plant-animal relationships is poorly understood, yet
these systems play important roles in the origin and maintenance of
biodiversity. Plants signal the availability of rewards to mutualists,
while at the same time “attempting to” minimise attraction of enemies.
Stabilising selection may often result from the net effect of these
two conflicting selective pressure, although this has only rarely been
documented. Floral signalling systems include bright colours and
fragrances to attract pollinators. Fully honest advertisements signal
accurately the presence of pollinator rewards (e.g. nectar, pollen, or
floral resin for nest construction), whereas dishonest advertisements
allow plants to attract and exploit pollinators without providing
rewards. There is a continuum between these extremes, however, as
measured by the correlation between advertisement “intensity” and
amount of reward available. With few exceptions, the honesty of
signalling systems is poorly understood, even though it not only
affects the nature of the trophic relationships, but also potentially
controls the evolutionary dynamics of plant-animal relationships. The
pollinator-signal systems employed by plants fall into two main
groups: visual (colour, shape) and olfactory (fragrances), and both
vary dramatically across the study system we are investigating.

The purpose of this study is to understand the evolutionary dynamic of
signal diversity in Dalechampia vines (Euphorbiaceae), assessing
evolutionary trends in floral bract and resin pigmentation and
fragrance production, in the context of bee-vision physiology, insect
learning, and overall honesty/dishonesty of signalling to both
pollinators and herbivores, in relation to rewards and defences. This
study is one of the first to elucidate the evolution of signalling
systems by assessing the effects of signal type on both reproductive
fitness in the field and, using molecular-phylogenetic relationships
in the genus, on diversification rates and trait-transition rates. The
PhD student collaborating on this project will work with Prof Scott
Armbruster and be involved in fieldwork in the tropics and greenhouse
and lab work at the University of Portsmouth and the Norwegian
University of Science and Technology (Trondheim). Additional expertise
and training will come from project collaborators in insect-vision
neurophysiology, bee behaviour, comparative methods and evolutionary
theory, based at other universities in the UK, Norway, and the US.

Informal inquiries can be directed to scott.armbruster@port.ac.uk or
+44 (0)23 9284 2081.

Application deadline 30th June 2011.

You can apply online, by email or by post to:
Faculty of Science, Faculty Admissions Centre, St. Michael's Building,
White Swan Road, Portsmouth, Hampshire, PO1 2DT.
Tel: +44 (0)23 9284 5550
Email : sci-pgrad@port.ac.uk

References:
Armbruster, W. S. 2002. Can indirect selection and genetic context
contribute to trait diversification? A transition-probability study of
blossom-color evolution in two genera. Journal of Evolutionary Biology
15: 468-486.
Armbruster, W. S., L. Antonsen, and C. Pélabon. 2005. Phenotypic
selection on Dalechampia blossoms: honest signaling affects
pollination success. Ecology 86: 3323-3333.
Bolstad G.H., W.S. Armbruster, C. Pelabon, R. Perez-Barrales, T.F.
Hansen. 2010. Direct selection at the blossom level on floral reward
by pollinators in a natural population of Dalechampia schottii:
Full-disclosure honesty? New Phytologist 188: 370-384.

--
W Scott Armbruster
University of Portsmouth, UK
& University of Alaska, USA

W Scott Armbruster <wsarmbruster@alaska.edu>