
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

38979251
10.1101/2024.06.26.600870
preprint
2
Article
Short-term fluctuating and long-term divergent selection on sympatric Monkeyflowers: insights from decade-spanning reciprocal transplants
Dong Caroline M. http://orcid.org/0000-0003-3352-4006

Aponte Rolón Bolívar http://orcid.org/0000-0002-2544-4551

Sullivan Juj K.
Tataru Diana http://orcid.org/0000-0003-2632-2262

Deleon Max
Dennis Rachael
Dutton Spencer
Machado Perez Fidel J.
Montano Lissette
Ferris Kathleen G. http://orcid.org/0000-0002-9611-0401

03 9 2024
2024.06.26.600870https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.06.26.600870
nihpp-2024.06.26.600870.pdf
ABSTRACT

Sympatric species are often locally adapted to distinct microhabitats. However, temporal variation may cause local maladaptation and species boundary breakdown, especially during extreme climatic events leading to episodic selection. Repeated reciprocal transplants can reveal the interplay between short and long-term patterns of natural selection. To examine evolutionary trajectories of sympatric Monkeyflowers adapted to different niches, Mimulus guttatus and M. laciniatus, we performed three replicated transplants and combined them with previous experiments to leverage a dataset of five transplants spanning 10 years. We performed phenotypic selection analyses on parents and hybrids in parental habitats in Yosemite NP, CA during years of drastically differing snowpack. If there is ecological isolation, then we predicted divergent phenotypic selection between habitats in line with species’ differences and local adaptation. We found interannual fluctuations in phenotypic selection, often in unpredicted directions. However, a combined-year analysis detected longer-term divergent selection on flowering time, a key temporally isolating and adaptative trait, suggesting that selection may reinforce species boundaries despite short-term fluctuations. Finally, we found temporal variation in local adaptation with M. laciniatus locally adapted in low snowpack years, while an extremely high snowpack year contributed to average local maladaptation of M. guttatus .
==== Body
pmc
