Biology subjects

Frederickson, M.

Publications and source records attributed to Frederickson, M..

4 recordsLinked to original sources

bioRxiv2023

Generalized mutualisms promote range expansion in both plant and ant partners

Mutualism improves organismal fitness, but strong dependence on another species can also limit a species ability to thrive in a new range if its partner is absent. We assembled a large, global dataset on mutualistic traits and species ranges to investigate how multiple plant-animal and plant-microbe mutualisms affect the spread of legumes and ants to novel ranges. We found that generalized mutualisms increase the likelihood that a species establishes and thrives beyond its native range, whereas specialized mutualisms either do not affect or reduce non-native spread. This pattern held in both legumes and ants, indicating that specificity between mutualistic partners is a key determinant of ecological success in a new habitat. Our global analysis shows that mutualism plays an important, if often overlooked, role in plant and insect invasions.

ecology↗

bioRxiv2022

Symbiosis with rhizobia limits range expansion only in polyploid legumes

O_LIBoth mutualism and polyploidy are thought to influence invasion success in plants but few studies have tested their joint effects. Mutualism can limit range expansion when plants cannot find a compatible partner in a novel habitat, or facilitate range expansion when mutualism increases a plants niche breadth. Polyploids are also expected to have greater niche breadth because of greater self-compatibility and phenotypic plasticity, increasing invasion success. C_LIO_LIFor 839 legume species, we compiled data from published sources to estimate ploidy, symbiotic status with rhizobia, specificity on rhizobia, and the number of introduced ranges. C_LIO_LIWe found that diploid species have had limited spread around the globe regardless of whether they are symbiotic or how many partners of rhizobia they can host. Polyploids, in contrast, have been successfully introduced to many new ranges, but interactions with rhizobia constrain their range expansion. In a hidden state model of trait evolution, we also found evidence of a high rate of re-diploidization in symbiotic legume lineages, suggesting that symbiosis and ploidy may interact at macroevolutionary scales. C_LIO_LIOverall, our results suggest that symbiosis with rhizobia affects range expansion only in polyploid legumes. C_LI

evolutionary biology↗

bioRxiv2019

Resilience to multiple stressors in an aquatic plant and its microbiome

PremiseEnvironments are changing rapidly, and outcomes of species interactions, especially mutualisms, are notoriously dependent on the environment. A growing number of studies have investigated responses of mutualisms to anthropogenic changes, yet most studies have focused on nutrient pollution or climate change, and tested single stressors. Relatively little is known about impacts of simultaneous chemical contaminants, which may differ fundamentally from nutrient or climate stressors, and are especially widespread in aquatic habitats.\n\nMethodsWe investigated the impacts of two common contaminants on interactions between the common duckweed Lemna minor and its microbiome. Sodium chloride (salt) and benzotriazole (a corrosion inhibitor) negatively affect aquatic organisms individually, yet commonly co-occur in runoff to duckweed-inhabited sites. We tested three L. minor genotypes with and without the culturable portion of their microbiome across field realistic gradients of salt (3 levels) and benzotriazole (4 levels) in a fully factorial experiment (72 treatments), and measured plant and microbial growth.\n\nKey ResultsWe found that stressors had conditional effects. Salt decreased both plant and microbial growth, but decreased plant survival more as benzotriazole concentrations increased. In contrast, benzotriazole did not affect microbial abundance, and benefited plants when salt and microbes were absent, perhaps due to the biotrans-formation we observed without salt. Microbes did not ameliorate duckweed stressors, as microbial inoculation increased plant growth, but not at high salt concentrations.\n\nConclusionsOur results suggest that multistressor effects matter when predicting responses of mutualisms to global change, but that mutualisms may not buffer organisms from stressors.

plant biology↗

bioRxiv2017

Dramatic differences in gut bacterial densities help to explain the relationship between diet and habitat in rainforest ants

Abundance is a key parameter in microbial ecology, and important to estimates of potential metabolite flux, impacts of dispersal, and sensitivity of samples to technical biases such as laboratory contamination. However, modern amplicon-based sequencing techniques by themselves typically provide no information about the absolute abundance of microbes. Here, we use fluorescence microscopy and quantitative PCR as independent estimates of microbial abundance to test the hypothesis that microbial symbionts have enabled ants to dominate tropical rainforest canopies by facilitating herbivorous diets, and compare these methods to microbial diversity profiles from 16S rRNA amplicon sequencing. Through a systematic survey of ants from a lowland tropical forest, we show that the density of gut microbiota varies across several orders of magnitude among ant lineages, with median individuals from many genera only marginally above detection limits. Supporting the hypothesis that microbial symbiosis is important to dominance in the canopy, we find that the abundance of gut bacteria is positively correlated with stable isotope proxies of herbivory among canopy-dwelling ants, but not among ground-dwelling ants. Notably, these broad findings are much more evident in the quantitative data than in the 16S rRNA sequencing data. Our results help to resolve a longstanding question in tropical rainforest ecology, and have broad implications for the interpretation of sequence-based surveys of microbial diversity.

ecology↗