We work on interactions among species that go on to influence population and community dynamics, and in some cases, evolution. We test ecological theory using detailed study of the behavior and natural history of species, monitoring of interacting species in the wild, manipulative experiments, and population genetics tools.
We have worked in the plant-Glanville fritillary butterfly-parasitoid wasp community study system in the Åland islands, Finland since 1998. After moving to the The Centre for Ecological Sciences at the Indian Institute of Science in Bangalore, India in autumn 2021, we have expanded to study other things. These new studies include tropical butterfly-parasitoid community structure, ecology of crop domestication, and arid grassland plant-insect community structure.
Highlights from recent work:
Effects of extreme weather events on butterfly behaviour in the urban environment of Bangalore, India
Watch a 2 minute video about the current collaborative project with researchers from the Indian Institute for Human Settlements (@RaviJambhekar, @JagdishKrishna8), funded by the Bengaluru Sustainability forum
Higher trophic level species, such as parasitoids, only persist in habitat patch networks with a high host occupancy
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.
Long term population genetic structure of interacting species
The genetic signature of introduced parasitoid wasp lineages gives us a window into what has happened in an island archipelago over the 25 years since their accidental introduction, including persistence through population bottlenecks, dispersal and interbreeding, as well as sorting among lineages depending on interaction between a hyperparasitoid and bacterial symbiont. @duplouy_anne @abhevo @Saskyavn @ParasitoidEcol
Duplouy A., Nair A., Nyman T., and van Nouhuys S. (2021). Long-term spatio-temporal genetic structure of an accidental parasitoid introduction, and local changes in prevalence of its associated Wolbachia symbiont. Molecular Ecology. doi: 10.1111/mec.16065
Strong direct and indirect interactions between species impact the performance of individuals. However, their impact is mostly swamped out by spatial and temporal variation of host plant quality.
We assessed the potential long term and landscape-level effects of plant-pathogen herbivore-parasitoid interactions on their dynamics. We found that while there are strong and weak interactions between species, most are swamped out by spatial and temporal variation of host plant quality.
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
Causes of spatial synchrony of butterfly population dynamics
During the last 20 years the population dynamics of the Glanville fritillary butterfly has become increasingly spatially synchronized over the Åland islands. We tested several possible mechanisms for this increased spatial synchrony and found that it is closely associated with increased synchrony of some aspects of weather, and is not driven by other aspects of weather, or by natural enemies.
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. PDF
Global Change Biology, doi:10.1111/gcb.14280
Pattern of specificity of a generalist parasitoid wasp
The generalist pupal parasitoid Pteromalus apum uses both M. cinxia and M. athalia butterflies as hosts. We found that these two hosts are equivalent with respect to the preference of the mother, development of the offspring and brood sex ratio. However, the host plant species the pupa is on, and where in the environment determined rate of parasitic and sex ratio of the broods.
Reudler J. H., van Nouhuys, S. (2018) The roles of foraging environment, host species and host diet for a generalist pupal parasitoid. PDF
Entomologia Experimentalis et Applicata, 10.1111/eea.12657