NERC/School of Life Sciences-funded PhD studentship at Sussex University
Environmental and genetic components of a major evolutionary transition
We seek a student interested in understanding the transition to sociality, one of the central problems in evolutionary biology. Functional (adaptive) questions about sociality have been well-studied, but much less is known about underlying mechanisms. Sweat bees (Halictinae) are unusually valuable for elucidating social transitions. Unlike other hymenopteran lineages, which comprise entirely social taxa (e.g. honeybees, paper wasps), there are closely related non-social as well as social sweat bees, and a well-resolved phylogeny suggests that there have been many transitions in both directions between sociality and non-sociality(1). Of special interest are socially polymorphic taxa such as Halictus rubicundus, where females in warmer environments form small social groups while those in cooler environments are non-social. Such taxa provide ideal material to investigate the underlying basis of sociality. In a recent study, we directly induced transitions between sociality and n
on-sociality by transplanting H. rubicundus reciprocally between UK populations that normally express alternative phenotypes(2) (see also http://www.sussex.ac.uk/newsandevents/index?id=3D5828, which includes a short video of H. rubicundus). In addition to these common garden experiments in the field(2), we are developing a method for rearing sweat bees in a controlled environment. The studentship would use these and other techniques to investigate how general social plasticity is in sweat bees, and to test potential environmental cues that determine social phenotype. Note that these are small (<1cm) bees that do not sting humans and live in colonies of <10 individuals. See our website (http://www.sussex.ac.uk/lifesci/fieldlab/) for more details of the research group. Possible foci for the research include:
(1) Social plasticity in UK sweat bees. Our previous findings(2) suggest that instead of representing repeated evolutionary gains and losses of the traits underpinning sociality, transitions between sociality and non-sociality might represent plasticity. The ability to express either sociality or non-sociality in response to environmental conditions might then be cryptic but widespread. This could be tested by carrying out common garden experiments with other UK sweat bees.
(2) Test for plasticity in North American populations of H. rubicundus. H. rubicundus has a holarctic distribution. There is significant mitochondrial differentiation between US populations expressing the two social phenotypes(3), whereas there is no such differentiation among British and Irish populations(4). This suggests that in the US, social phenotype might be genetically fixed rather than flexible. These and other differences between US and UK bees could also be examined.
(3) Environmental cues that sweat bees use to determine which social phenotype to express are currently unknown. The effect of cues such as daylength, temperature and mating status(5) could be investigated.
The balance between these aims will depend on initial results and the developing interests of the student. My group is collaborating with that of Prof Rob Paxton, a molecular ecologist at University of Halle in Germany. Prof Paxton's group is currently annotating the transcriptome of H. rubicundus. Although it would not be the main focus, it is possible that towards the end of the study, the PhD student could be involved in RNA expression work using H. rubicundus samples collected during the studentship.
References:
(1) Danforth, B.N., Conway, L., and Ji, S.Q. (2003). Phylogeny of eusocial Lasioglossum reveals multiple losses of eusociality within a primitively eusocial clade of bees (Hymenoptera : Halictidae). Syst Biol 52, 23-36.
(2) Field, J., Paxton, R.J., Soro, A. & Bridge, C. (2010). Cryptic plasticity underlies a major evolutionary transition. Current Biology 20:2028-31. [see also commentary on this paper in Current Biology 20:R977-9, 2010]
(3) Soucy, S.L., and Danforth, B.N. (2002). Phylogeography of the socially polymorphic sweat bee Halictus rubicundus (Hymenoptera : Halictidae). Evolution 56, 330-341.
(4) Soro, A., Field, J., Bridge, C., Cardinal, S.C. & Paxton, R.J. (2010). Genetic differentiation across the social transition in a socially polymorphic sweat bee, Halictus rubicundus. Molecular Ecology 19:3351-3363.
(5) Yanega, D. (1989). Caste determination and differential diapause within the first brood of Halictus rubicundus in New York (Hymenoptera: Halictidae). Behavioural Ecology and Sociobiology 24, 97-107.
REQUIREMENTS: a student with an interest in behavioural/evolutionary ecology, who has or expects to receive at least a 2:1 degree and is a UK citizen. If you are a citizen of another European Union (EU) member state you will not generally be eligible, unless you have spent the previous three years in the UK undertaking education (undergraduate study or masters) (see below for full eligibility details). The successful applicant will have a fitness level suitable for work in the field. A driving license would be useful. Because the work involves recording colour marks on individual animals, it would not be suitable for someone who is colour-blind.
The studentship will be joint-funded by NERC and the School of Life Sciences at Sussex University, and could commence in either October 2011 or January 2012. Full funding is definitely available for 3.5 years, including research costs. In addition to research, the student will be expected to contribute up to 50 hours per academic year demonstrating/tutorial teaching etc. without additional remuneration. Sussex is one of the leading research-led universities in the UK, with an international reputation for innovation and interdisciplinarity in research. The School of Life Sciences is a well-equipped research environment, providing excellent opportunities to interact with leading researchers. Tom Collett, Paul Graham, Jeremy Field and Francis Ratnieks all lead well-established research groups focussing on social insects. Major research themes in the School are Evolution, Behaviour and Environment (EBE), Neuroscience, Genome Damage and Biochemistry, Chemistry and Molecular Biolog
y (see http://www.sussex.ac.uk/lifesci/research).
APPLICATIONS
Applicants should email a covering letter and CV to Jeremy Field (j.field@sussex.ac.uk). The CV should include:
1. Contact details (including e-mail addresses) for the applicant and 2-3 referees who would be available to provide references during June/July 2011.
2. The applicant's availability for interview at Sussex University during June/July 2011.
Informal enquiries: e-mail Jeremy Field (j.field@sussex.ac.uk)
ELIGIBILITY
To be eligible for the studentship (stipend and university fees), candidates must be:
A UK national who can demonstrate a relevant connection (1) to the UK; or an individual who was not born in the UK but has been granted UK citizenship or has come to settle in the UK (for example immigrant status, refugee or an individual granted humanitarian protection) and can demonstrate that they have a relevant connection through ordinary residence (2). Or a European Economic Area (3) citizen who is a migrant worker (4) (or their spouse or children) and can demonstrate ordinary residence in the EEA. Or an EU national who has spent the three years prior to application resident in the UK (this can include residence whilst undertaking undergraduate study).
(1). A relevant connection can be established if an individual has been ordinarily resident in the UK throughout the three years preceding the date of application. Candidates may be classed as demonstrating ordinary residence when they are temporarily absent overseas (see below) where the nature of their profession demands that they spend periods overseas (for example research) or have been receiving full-time education overseas.
(2). Lord Scarman defined ordinary residence as 'habitual and normal..from choice and for a settled purpose throughout the prescribed period, apart from temporary or occasional absence' '.voluntarily adopted…' 'there must be some degree of settled purpose (and) a sufficient degree of continuity to be properly described as settled'. Ordinary residence is proven if a candidate would have been in the UK (or EEA) if it were not for the fact that s/he, his/her spouse, parent or guardian is/was temporarily employed outside of the area.
(3). The European Economic Area is defined as the areas comprised by the member states of the European Union (Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden) as well as Iceland, Liechtenstein, Norway and Switzerland.
(4). An EEA migrant worker can be defined (for these purposes) as a citizen of a member state of the EEA who is employed in the UK and who should be treated as a national of the UK. The employment of an EEA migrant worker can be full-time or part-time but must be relevant to the candidate's previous or future training. Candidates employed in part-time or short-term casual employment or who are effectively unemployed cannot be considered to hold migrant worker status.
Professor Jeremy Field
School of Life Sciences,
John Maynard Smith Building,
University of Sussex,
Falmer,
Brighton BN1 9QG, UK
j.field@sussex.ac.uk
http://www.sussex.ac.uk/lifesci/fieldlab/