My group and I study the mechanisms (e.g. selection, migration) that influence the maintenance of genetic diversity in asexual-sexual species complexes, using the freshwater cladoceran genus, Daphnia, as our primary model organism. My research bridges the fields of population genetics, environmental genomics, and evolutionary ecology. In my lab, a variety of molecular techniques (e.g. microsatellites, DNA sequencing, and Next-Gen genomics) are used to examine the population genetic/genomic structure of aquatic organisms, with most of my work focusing on zooplankton. We currently have a number of major projects. The first project with a variety of international colleagues (i.e., Belgium, Canada, Germany, and Norway) has been examining long-term (i.e. decadal) changes in arctic rockpool and tundra pond population genetic structure, as well as community structure among zooplankton related to climate change.   A second major project funded by the U.S. National Science Foundation (NSF) with colleagues at Oklahoma State University, and the St. Croix River (MN) Watershed Research Station (and Science Museum of Minnesota) has been focusing on the ecological and genetic information held in lake/pond sediment egg banks of freshwater invertebrates, primarily Daphnia.  We employ a variety of techniques spanning the fields of paleolimnology (i.e., “resurrection ecology”), molecular genetics, ecology (i.e. direct hatching of eggs, selection experiments), and environmental genomics (i.e. Next-Gen sequencing) to examine long-term (i.e. decades, centuries) shifts in population genetic/genomic structure that may be associated with concomitant shifts in environmental factors (e.g. nutrient/eutrophication history).  We aim to look at how shifts in environmental factors may influence long-term temporal genetic heterogeneity in natural populations. 

• Marková, S., M. Strážnická, H. Lanier, H. Henttonen, J. Searle, L.J Weider and P. Kotlík. 2020. High genomic diversity in the bank vole at the northern apex of a range expansion: the role of multiple colonizations and end-glacial refugia. Molecular Ecology 29:1730-1744. https://doi.org/10.1111/mec.15427
• Kiehnau, E.L. and L.J. Weider. 2019. Phototactic behavior of native Daphnia in the presence of chemical cues from the non-native predator Bythotrephes. Oecologia 190:799-809. https://doi.org/10.1007/s00442-019-04461-6
• Yousey, A.M., P. Roy Chowdhury, N. Biddinger, J. Shaw, P.D. Jeyasingh and L.J. Weider. 2018. Resurrected “ancient” Daphnia genotypes show reduced thermal stress tolerance compared to modern descendants. Royal Society Open Science 5: 172193.http://dx.doi.org/10.1098/rsos.172193
• Weider, L.J., P.D. Jeyasingh, and D. Frisch. 2018. Evolutionary aspects of resurrection ecology: Progress, scope, and applications – an overview. Evolutionary Applications 11: 3-10.
• Frisch, D., P.K. Morton, B. Culver, M. Edlund, P.D. Jeyasingh, and L.J. Weider. 2017. Paleogenetic records of Daphnia pulicaria in two North American lakes reveal the impact of cultural eutrophication. Global Change Biology 23:708-718; DOI: 10.1111/gcb.13445
• Muñoz, J., A. Chaturvedi, L. De Meester, and L.J. Weider. 2016. Characterization of genome-wide SNPs for the water flea Daphnia pulicaria generated by genotyping-by-sequencing (GBS). Scientific Reports DOI: 10.1038/srep28569
• Roy Chowdhury, P., D. Frisch, D. Becker, J. A. Lopez, L.J. Weider, J.K. Colbourne, and P.D. Jeyasingh. 2015. Differential transcriptomic responses of ancient and modern Daphnia genotypes to phosphorus supply. Molecular Ecology 24:123-135.
• Frisch, D., P.K. Morton, P. Roy Chowdhury, B. Culver, J.K. Colbourne, L.J. Weider, and P.D. Jeyasingh. 2014. A millennial-scale chronicle of evolutionary responses to cultural eutrophication in Daphnia. Ecology Letters 17:360-368.
• Orsini, L., K. Schwenk, L. De Meester, J.K. Colbourne, M.E. Pfrender and L.J. Weider. 2013. The evolutionary time machine: Forecasting how populations can adapt to changing environments using dormant propagules.Trends in Ecology and Evolution 28:274-282.
• Latta, L.C. IV, L.J. Weider, J.K. Colbourne, and M.E. Pfrender. 2012. The evolution of salinity tolerance inDaphnia: A functional genomics approach. Ecology Letters 15:794-802. (Faculty of 1000 publication).
• Hargrave, C.W., K.D. Hambright, and L.J. Weider. 2011. Variation in resource consumption across a gradient of increasing intra- and inter-specific richness. Ecology 92:1226-1235.
• Weider, L.J., D. Frisch, and P.D.N. Hebert. 2010. Long-term changes in metapopulation genetic structure: A quarter-century retrospective study on low-Arctic rock pool Daphnia. Proc. R. Soc. Lond. Series B 277:139-146.
• Hessen, D.O., P.D. Jeyasingh, M. Neiman, and L.J. Weider. 2010. Genome streamlining and the elemental costs of growth. Trends in Ecology & Evolution 25:75-80.
• Jeyasingh, P.D., L.J. Weider, and R.W. Sterner. 2009. Genetically-based trade-offs in response to stoichiometric food quality influence competition in a keystone aquatic herbivore. Ecology Letters 12:1229-1237.
• Weider, L.J., P.D. Jeyasingh, and K.G. Looper. 2008. Stoichiometric differences in food quality: impacts on genetic diversity and coexistence of aquatic herbivores in a Daphnia hybrid complex. Oecologia 158:47-55.
• Jeyasingh, P.D. and Weider, L.J. 2007. Fundamental links between genes and elements: evolutionary relevance of ecological stoichiometry. Molecular Ecology (invited review) 16:4649-4661.
• Weider, L.J., J.J. Elser, T.J. Crease, M. Mateos, J. Cotner, and T. Markow. 2005. The functional significance of ribosomal(r)DNA variation: Impacts on the evolutionary ecology of organisms. Annual Review Ecology Evolution Systematics 36:219-242.
• Jeyasingh, P.D. and L.J. Weider. 2005. Phosphorus availability mediates plasticity in life history traits and predator-prey interactions in Daphnia. Ecology Letters 8:1021-1028.
• Weider, L.J., W. Makino, K. Acharya, K.L. Glenn, M. Kyle, J. Urabe and J.J. Elser. 2005. Genotype x environment interactions, stoichiometric food quality effects, and clonal coexistence in Daphnia pulex. Oecologia 143:537-547.
• Weider, L.J. and A. Hobæk. 2003. Glacial refugia, haplotype distributions, and clonal richness in the Daphnia pulex complex in arctic Canada. Molecular Ecology 12:463-473.
• Limburg, P.A. and L.J. Weider. 2002. "Ancient" DNA in a microcrustacean resting egg bank can serve as a paleolimnological database. Proc. R. Soc. Lond. Series B. 269:281-287.
• Elser, J.J., R.W. Sterner, E. Gorokhova, W.Fagan, T. Markow, J. Cotner, J. Harrison, S.Hobbie, G. Odell, andL.J. Weider. 2000. Biological stoichiometry from genes to ecosystems. Ecology Letters 3:540-550.
• Hairston, N.G. Jr., W. Lampert, C. Cáceres, C.L. Holtmeier, L. J. Weider, U. Gaedke, J.M. Fisher, J. A. Fox, and D. M. Post. 1999. Rapid evolution revealed by dormant eggs. Nature 401:446.