Metacommunity Ecology Group

Open positions

1) PhD:Parasitoid metacommunity ecology
2) Pro Gradu: Habitat fragmentation and the performance of a wind and an insect pollinated plant
3) Pro Gradu:The effect of habitat fragmentation on the fungal pathogen community infecting Veronica spicata
4) Pro Gradu: Competition among closely related parasitoids sharing the same host species
5) Pro Gradu: Parasitoid-hyperparasitoid population dynamics
6) Pro Gradu: Intraspecific competition and local mate competition among gregarious parasitoids

1) PhD student position in PARASITOID METACOMMUNITY ECOLOGY

The student will research patterns of metacommunity structure and the mechanisms behind them using the community surrounding the Glanville fritillary butterfly (Melitaea cinxia) in the Åland islands, Finland.   Example topics are (1) exploration of the prediction that food-chain length decreases with habitat fragmentation, (2) the landscape level effects of indirect interactions between butterflies and between parasitoids, and (3) the role of space in multitrophic level interactions. The work will have a field component and can have lab and/or mathematical components. The applicant must have a strong interest in population and community ecology and a Masters Degree or equivalent.  Information about the research system.

The successful applicant will be a PhD student in the metacommunity ecology group, a subgroup of the Metapopulation Research Group, at the University of Helsinki. We are a Centre of Excellence supported by the Academy of Finland. We have an international research environment with opportunities for mixing among ecologists, molecular biologists and mathematicians.  The position is for completion of a PhD within four years. Salary is based on the University salary system and is about 2,300 €/month plus social benefits. Please send your application or any enquiries to Saskya van Nouhuys (saskya.vannouhuys@helsinki.fi).  Your application should include a short CV, a one page explanation of your motivation and suitability for the project and the e-mail addresses of three researchers who can document that you are self-motivated and can do productive independent work.  Consideration of applications began in July 2009 and will continue until the position is filled.

2) Pro Gradu project: Habitat fragmentation and the performance of a wind and an insect pollinated plant

3) Pro Gradu project: The effect of habitat fragmentation on the fungal pathogen community infecting Veronica spicata

Pro Gradu projects in parasitoid population and community ecology

For each project listed below the student would write a plan winter/spring 09/10 and do the field/laboratory part of the research spring-summer 2010 under the supervision of Saskya van Nouhuys. Accommodation during fieldwork (in Åland) and a stipend for up to two months of fieldwork is available.

For information about the research system see: http://www.eeb.cornell.edu/sdv2/saskya%20www/Research%20summary%202.html or http://www.helsinki.fi/science/metapop/metacom/research/metacom_structure.htm

Interested students should contact Saskya by email saskya.vannouhuys@helsinki.fi

4) Competition among closely related parasitoids sharing the same host species
In the Åland islands the butterfly Melitaea athalia is host to two parasitoids in the genus Cotesia. These parasitoids have no other hosts and are ecologically similar. Therefore there is potential for strong competition between them, yet both persist and even co-occur in the same local host populations.

We are looking for a student to work on the mechanism of coexistence of these parasitoids. Currently, this means a student would compare their physiology, behaviour and natural history under laboratory conditions. For instance, the student may design an experiment comparing the competitive ability of the parasitoids developing in the host. Or, the student may compare the degree of adaptation to the chemical defence of the host. The specifics and independence of the project would depend on the students interests and experience.

5) Parasitoid-hyperparasitoid population dynamics
Parasitoids are sandwiched between their hosts and their own hyperparasitoids. Thus their success is constrained both from below (by their host) and above (by their hyperparasitoid).  We are looking for a student interested in studying this three-way interaction experimentally.

In the Åland islands 1/3 of the larvae of the butterfly Melitaea cinxia are parasitized by Hyposoter horticola, which are themselves parasitized at rate of 25 to 60 % by Mesochorus stigmaticus.  There are two projects available:

Density dependence of hyperparasitism: Conduct a behavioral experiment to understand hyperparasitoid aggregation in response to parasitoid density, at both small and large spatial scales.
Local adaptation of oviposition behavior: Conduct a behavioral experiment testing the hypothesis that the parasitoid H. horticola has evolved a low rate of parasitism in the presence of its hyperparasitoid (Åland islands), and a high rate of parasitism where the hyperparasitoid is absent (Estonia).

6) Intraspecific competition and local mate competition among gregarious parasitoids
The parasitoid Pteromalus apum lays eggs on butterfly pupae.  Mother wasps lay multiple eggs per host, and a butterfly pupa may be host to the progeny of several mothers.  So a single butterfly pupa may harbor up to 80 immature parasitoids, both siblings and non-siblings.

We are interested in the biology and behavior of the parasitoid P. apum in this complex competitive situation. Currently we are particularly interested in addressing 1) the ability of the parasitoid to sib-mate, and the outcome of sibling vs. non-sibling matings, and 2) the association of progeny sex ratio with the number of related and unrelated females using a host. This work will be conducted in the Åland islands, using P. apum and the hosts Melitaea cinxia and M. athalia