Maya Weissman

Maya Weissman

PhD Student at Brown University and member of the Weinreich Lab.

Sitemap

A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

Pages

Posts

outreach

The Coral Microbiome


What do your stomach and a coral reefs have in common? Learn more about my research on the coral microbiome!

Microbe Madness


Bacteria, viruses, fungi, pathogens, and more! Made in partnership with the Brown Junior Researchers.

Ecology Explorers


Explore how organisms interact with each other and their environment and conduct an experiment using a Field Notebook.

Bet Hedging


Plants, animals, and microbes all use bet hedging to survive unpredictable environmental change. Learn more about my PhD thesis research on the evolution of bet hedging!

Darwin Day


Learn about Charles Darwin, one of the fathers of the modern evolutionary synthesis.

portfolio

Undergraduate Research


Undergraduate research with the SDSU DiMoLab mathematically modeling disease dynamics in HIV and coral reef black band disease.

PhD Research


PhD thesis research with the Brown Weinreich Lab on modeling the evolution of bet hedging.

publications

Beyond the (geometric) mean: stochastic models undermine deterministic predictions of bet hedger evolution

Bet hedging is a ubiquitous strategy for risk reduction in the face of unpredictable environmental change where a lineage lowers its variance in fitness across environments at the expense of also lowering its arithmetic mean fitness. Classically, the benefit of bet hedging has been quantified using geometric mean fitness (GMF); bet hedging is expected to evolve if and only if it has a higher GMF than the wild-type. We build upon previous research on the effect of incorporating stochasticity in phenotypic distribution, environment, and reproduction to investigate the extent to which these sources of stochasticity will impact the evolution of real-world bet hedging traits. We utilize both individual-based simulations and Markov chain numerics to demonstrate that modeling stochasticity can alter the sign of selection for the bet hedger compared to deterministic predictions. We find that bet hedging can be deleterious at small population sizes and beneficial at larger population sizes. This non-monotonic dependence of the sign of selection on population size, known as sign inversion, exists across parameter space for both conservative and diversified bet hedgers. We apply our model to published data of bet hedging strategies to show that sign inversion exists for biologically relevant parameters in two study systems: Papaver dubium, an annual poppy with variable germination phenology, and Salmonella typhimurium, a pathogenic bacteria that exhibits antibiotic persistence. Taken together, our results suggest that GMF is not enough to predict when bet hedging is adaptive.

Recommended citation: Beyond the (geometric) mean: stochastic models undermine deterministic predictions of bet hedger evolution. Maya Weissman, Yevgeniy Raynes, Daniel Weinreich. bioRxiv. 2023.07.11.548608; doi: https://doi.org/10.1101/2023.07.11.548608 https://www.biorxiv.org/content/10.1101/2023.07.11.548608v2

Balancing the risks of mating: biogeographic evidence of cleistogamy as a bet hedging strategyn

Cleistogamy is a mating system in which plants produce some proportion of closed, autonomously self-pollinating flowers. Cleistogamous flowers differ from chasmogamous flowers, which are open flowers capable of outcrossing. Both dimorphic cleistogamy (cleistogamous and chasmogamous flowers produced on the same plant) and complete cleistogamy occur. Cleistogamy has been hypothesized to be a bet hedging strategy for reducing risk in the face of unpredictable pollinator availability. However, conflicting results across species and challenges connecting theory to data have prevented researchers from proving that cleistogamy is bet hedging. To test the bet hedging hypothesis, we investigated the distribution of over 400 cleistogamous species through biogeographical analyses. We find that cleistogamy is more prevalent in cooler, more variable environments. Additionally, we find that among cleistogamous species, complete cleistogamy is more likely to occur in warmer, more stable, tropical and subtropical environments. We hypothesize that the difference in distribution between complete and dimorphic cleistogamy may be driven by the opposing forces of selection to increase cleistogamy proportion and extinction risk, which we test using a heuristic Markov transition model. We conclude that the distribution of cleistogamy suggests that the strategy has evolved in variable environments, consistent with expectations for bet hedging.

Recommended citation: Balancing the risks of mating: biogeographic evidence of cleistogamy as a bet hedging strategy. Maya R. Weissman, Dafeng Zhang, Rebecca Kartzinel, Daniel Weinreich. bioRxiv March 2024. https://doi.org/10.1101/2024.03.28.587200. https://doi.org/10.1101/2024.03.28.587200

Modeling the Role of Temperature-Dependent Microbiome Composition in Black Band Disease Transmission Among Coral Reefs

Black band disease (BBD) is one of the most prevalent diseases causing significant destruction of coral reefs. Coral reefs acquire this deadly disease from bacteria in the microbiome community, the composition of which is highly affected by the environmental temperature. While previous studies have provided valuable insights into various aspects of BBD, the temperature-dependent microbiome composition has not been considered in existing BBD models. We developed a transmission dynamics model, incorporating the effects of temperature on the microbiome composition and, subsequently, on BBD in coral reefs. Based on our non-autonomous model systems, we calculate the infection invasion threshold, providing an environmental condition for the disease to persist in the coral reef community. Our results suggest that temperature significantly impacts coral reef health, with microbiome-favored moderate environmental temperatures resulting in more BBD-infected corals. Our model and related results help investigate potential strategies to protect reef ecosystems from stressors, including BBD.

Recommended citation: Modeling the Role of Temperature-Dependent Microbiome Composition in Black Band Disease Transmission Among Coral Reefs. Alex Busalacchi, Maya Weissman, Feng-Bin Wang, Naveen Vaidya. June 2024.

talks

Mathematically Modeling the Coral Reef Microbiome

A poster presentation on modeling the coral reef microbiome. This talk won the Undergraduate Research Excellence award at the SDSU Student Research Symposium. This work was also invited to be presented at the SIAM Southern California Conference and the Inauguration of SDSU President Adela de la Torre.

teaching

Evolutionary Biology

Fall 2022 Head Teaching Assistant duties included leading weekly discussion sections, grading homework and tests, holding office hours, answering clarifying questions, and hosting two guest lectures.

Adjunct Assistant Professor

Instructor of record for Biol 0380: The Ecology and Evolution of Infectious Diseases. Course enrollment is 80 students.