Biology subjects

LaPlante, E. R.

Publications and source records attributed to LaPlante, E. R..

3 recordsLinked to original sources

bioRxiv2026

Multiple host species maintain genetic diversity in herbivore populations

How natural populations maintain genetic variation for fitness remains a central problem in evolutionary biology. Theory predicts that opposing selective pressures across environments can preserve fitness-associated polymorphism, but how interactions among species contribute to this process remains poorly understood. Here we show that host diversity preserves standing genetic variation within sexual populations of the leafmining fly Scaptomyza flava. We evolved twelve populations for ten generations on either of two naturally co-occurring host plants or on both, pooling survivors from the two hosts before mating. Single-host populations evolved reciprocal fitness trade-offs, whereas two-host populations maintained relatively even performance across hosts. Whole-genome time series dynamics identified a linked region in which alleles increased on one host and decreased on the other, while showing little net change under two-host conditions. Wild flies reared from the two hosts showed corresponding allele-frequency differences within this region. Across the genome, two-host populations retained more rare variants than populations evolving on either host alone. These findings show that selection imposed by different host species in sympatry can maintain standing genetic diversity within an herbivore population.

evolutionary biology↗

bioRxiv2026

Foliar striping and floral traits are correlated with higher reproductive output in crimson monkeyflowers

In plants, ecological interactions such as pollination depend on whole-plant phenotypes, where coordinated variation among vegetative, floral, and reproductive traits can shape reproductive success. However, empirical studies linking integrated phenotypes that include non-floral traits to reproductive outcomes within populations remain limited. While prior work has shown that crimson monkeyflowers exhibit heritable variation in foliar anthocyanin striping, the functional significance of the trait has been thus far unknown. Using plants derived from natural populations, we conducted field and greenhouse experiments to assess whether foliar striping is genetically correlated with traits related to pollinator attraction. We found that foliar striped plants consistently exhibit larger flowers, greater nectar rewards, and decreased proportions of viable pollen relative to non-striped plants. When we manipulated flowers within plants with and without foliar striping to allow only outcrossing or only self-fertilization in a field environment, we found that outcrossed flowers had higher reproductive success than did self-fertilized, with outcrossed flowers from plants with foliar striping producing the highest overall seed numbers and seed mass. Our results reveal patterns of coordinated foliar and floral trait variation and associated reproductive output that are consistent with a pollination syndrome framework. The link between foliar pigmentation and increased per-calyx reproductive output represents a novel association between foliar pigmentation and a broader evolutionary and ecological function.

ecology↗

bioRxiv2017

Genetic variants affecting plant size and chemical defenses jointly shape herbivory in Arabidopsis

Herbivorous insects exhibit strong feeding preferences when choosing among plant genotypes, yet experiments to map loci mediating plant susceptibility to herbivory rarely incorporate host choice. To address this gap, we applied genome-wide association (GWA) mapping to uncover genetic polymorphisms mediating damage from foraging insects (two populations of Scaptomyza flava) across a mixture of Arabidopsis thaliana genotypes in experimental enclosures. The effect of chemical defenses (glucosinolates) on herbivory depended on herbivore genotype. Unlike many studies that minimize the effects of host choice behavior, we also found a large effect of plant size on herbivory--likely through its effect on plant apparency--that was independent of herbivore genotype. These herbivory-associated loci are polymorphic at fine spatial scales, and thus have potential to shape variation in herbivory within natural populations. We also show that the polymorphism with the largest effect on herbivory underlies adaptive latitudinal variation in Arabidopsis plant size across Europe. Overall, our results provide genetic support for ecological observations that variation in both chemical defenses and non-canonical defense traits (e.g., plant size and phenology) jointly shapes plant-herbivore interactions.

plant biology↗