COS 252-5 - CANCELLED - Spatial habitat heterogeneity influences host-pathogen dynamics in a patchy population of Ranchman’s tiger moth

Thursday, August 18, 2022

2:30 PM – 2:45 PM EDT

Location: 515C

Presenting Author(s)

AP

Adam A. Pepi

Tufts University, United States

Coauthor(s)

VP

Vincent S. Pan

Graduate Student
Department of Integrative Biology, Michigan State University
East Lansing, Michigan, United States
RK

Richard K. Karban

University of California Davis, United States
MH

Marcel Holyoak

University of California Davis, United States
PG

Patrick Grof-Tisza

University of Neuchâtel, Switzerland
AL

Aiyanna Lawson-McNeil

University of California Davis, United States
VM

Vinay Mase

University of California Davis, United States
AB

Alexis Ballman

University of California Davis, United States
CM

Cameron Moseley

University of California Davis, United States

Background/Question/Methods

Host-pathogen dynamics are influenced by many factors that vary locally, but models of disease rarely consider dynamics across spatially heterogeneous environments. In addition, theory predicts that dispersal will influence host-pathogen dynamics of populations that are linked, though this has not been examined empirically in natural systems. In the present study, we examined the spatial dynamics of a patchy tiger moth-baculovirus-host system, in which habitat type influences dynamics. Theoretical models of host-baculovirus dynamics predict that such variation in dynamics between habitat types could be driven by range of factors, of which we predict two are likely to be operating in this system: a) differences in environmental persistence of pathogens or b) differences in host intrinsic rates of increase. We used time series models and monitored infection rates of hosts to characterize dynamics and distinguish between these possibilities. We also examined the role of climate and host dispersal (connectivity) as important contributors to dynamics, using time series models and experiments.

Results/Conclusions

We found that population growth rate was higher, delayed density-dependence was weaker, and that long-period oscillations were lower amplitude in high quality habitat patches. Infection rate was higher on average in high quality habitat, but model selection shows that this can be explained by higher mean population densities and not differences in pathogen persistence in the environment (delayed density-dependence). Time series modelling and experiments also showed an interactive effect of temperature and precipitation on moth population growth rates (likely caused by variation in host plant quality and quantity), and an effect of connectivity. Our results showed that spatial heterogeneity and connectivity were important in driving host-baculovirus dynamics, and integrated the complexity of climate variation and spatial connectivity into host-pathogen dynamics.