Population ecology

We study the spatial population dynamics of closely interacting species in a fragmented landscape by examining their life history, behavior and natural history, and using population genetics tools. For instance, we have found that over the long term that (meta)population dynamics of the parasitoids of the butterfly Melitaea cinixa  are influenced by host dynamics, dispersal ability, host plant species, hyperparasitism, competition, and temperature mediated phenology.  In contrast, the dynamics of the butterfly host is driven strongly by weather. For more details scroll down to the sections below.

We also work on the population level eco-evolutionary dynamics of parasitoid virulence and host resistance, both in terms of physiological immunity and behavior. Finally, we work on the effects of landscape structure on species traits on biological control of agricultural pests by parasitoids. See:
Jervis, M.A. Kidd, N.A.C., Mills, N.J., van Nouhuys, S.Singh, A., Yazdani, M. * (2023, in press) Population Dynamics. In: Hardy ICW & Wajnberg E (Eds) Jervis’s Insects as natural enemies: practical perspectives. Springer, Dordrecht.

The effects of species interaction and spatial structure of the landscape on population dynamics and genetic structure.

The population dynamics of species depend on the distribution and stability of resources and enemies, population size and the extent to which individuals move between resource patches. It isn’t simple to disentangle what biotic and abiotic factors go into explaining the dynamics of species. A recent study showed that increasing synchrony of population dynamics of the butterfly M. cinxia can be explained by weather extremes, and not interaction with natural enemies

Increasing synchrony of butterfly population dynamics are associated with increasing synchrony in weather.

Kahilainen, A., van Nouhuys, S., Schulz, T. & Saastamoinen, M. 2018
Metapopulation dynamics in a changing climate: Increasing spatial synchrony in weather conditions drives metapopulation synchrony of a butterfly inhabiting a fragmented landscape
Global Change Biology, 24: 10.1111/gcb.14280

We are also using Population genetics tools to exploring the association of population structure with environment (such a habitat connectivity), resource distribution (host population dynamics), life history (i.e. population size and sex ratio), and interactions such as competition (we are using primarily neutral microsatellite markers) of the butterfly M. cinxia and its parasitoids in a landscape.

One clear pattern is that higher trophic level species have lower spatial genetic structure.  This is not surprising because as trophic level increases the resource becomes sparse and unpredictable, so individuals must be mobile, leading to population mixing.

Multilocus genetic clusters for each species mapped onto the map of the Åland islands

Wang, S., Brose, U., van Nouhuys, S., Holt, R. D. and Loreau, M. 2021 Metapopulation capacity determines food chain length in fragmented landscapes. Proceedings of the National Academy of Sciences, 118, e2102733118.

Duplouy, A., Nair, A., Nyman, T., van Nouhuys, S. 2021
Long-term spatiotemporal genetic structure of an accidental parasitoid introduction, and local changes in prevalence of its associated Wolbachia symbiont. Molecular Ecology, 30, 4368-4380

Opedal, Ø., Ovaskainen, O., Saastamoinen, M., Laine, A-L., van Nouhuys, S. 2020
Host plant availability drives the spatio-temporal dynamics of interacting metapopulations across a fragmented landscape.
Ecology, 101(12):e03186. 10.1002/ecy.3186

55. Nair, A., Nonaka , E., van Nouhuys, S.  2018
Increased fluctuation in a butterfly metapopulation leads to diploid males and decline of a hyperparasitoid
Proceedings of the Royal Society B, 285: 10.1098/rspb.2018.0372

Nair, A., Fountain, T., Ikonen, S., Ojanen, S. P., van Nouhuys, S. 2016. Spatial and temporal genetic structure at the fourth trophic level in a fragmented landscape. Proceedings of the Royal Society B, 283: 10.1098/rspb.2016.0668

Couchoux,, C., Seppä, P., van Nouhuys,, S. 2016. Strong dispersal in a parasitoid wasp overwhelms habitat fragmentation and host population dynamics.  Molecular Ecology,  doi: 10.1111/mec.13696

van Nouhuys, S. 2016.  Diversity, population structure and individual behavior of parasitoids as seen using molecular markers. Current opinions in Insect Science 14: 94-99.

Couchoux, C., Seppä, P., van Nouhuys, S. 2015. Microsatellites for the parasitoid wasp Hyposoter horticola. Conservation Genetics Resources, 7: 595-597 

Nair, A., van Nouhuys, S. 2015. Microsatellite markers for a hyperparasitoid wasp from a fragmented landscape. Conservation Genetics Resources, 7: 565-586

Kankare, M., van Nouhuys, S., Gaggiotti, O., Hanski, I. 2005. Metapopulation genetic structure of two coexisting parasitoids of the Glanville fritillary butterfly. Oecologia, 143: 77-84