My research integrates population genomics and phylogenomics to understand how reproductive strategies evolve across landscapes. I am currently building Catopsis as a model system to to do so. Currenly I am investigating the demographic and ecological drivers of sexual system evolution and their consequences for diversification and species boundaries.
Catopsis Griseb. is an epiphytic genus in the bromeliad subfamily Tillandsioideae. Its greatest diversity lies in Mexico, though species range across the Caribbean, Central America, and the Brazilian Shield of South America.
Remarkably, Catopsis is one of the few bromeliad lineages with dioecious species, a rarity within the family. Elsewhere, dioecy is documented only in Hechtia (Hechtioideae), the monotypic Androlepis skinneri, and Aechmea mariae-reginae (both Bromelioideae).
Both Hechtia and Catopsis share Mexico as their diversity center, while the two Bromelioideae species are found in Central America.
Benzing, 2000Despite this intriguing distribution, dioecious bromeliads remain underexplored in studies of genetic diversity, reproductive biology, and evolutionary ecology. This makes Catopsis an especially useful system for testing how reproductive strategies evolve across geography.
Further Reading
- Benzing, D.H. (2000). Bromeliaceae: Profile of an Adaptive Radiation. Cambridge University Press.
- Givnish, T.J. et al. (2014). Adaptive radiation and diversification in Bromeliaceae. Molecular Phylogenetics and Evolution.
- RamÃrez-Morillo, I., et al. (2004). Reproductive biology and sexual systems in Catopsis.
Sexual system variation in Catopsis nutans
A major focus of my dissertation is Catopsis nutans, a widespread Neotropical epiphyte that exhibits striking geographic variation in sexual system. Populations in Mexico and northern Central America are primarily dioecious, with separate male and female individuals, while populations near the northern and southern range margins are hermaphroditic.
This distribution raises a central evolutionary question: did hermaphroditism evolve once, followed by geographic expansion, or has it evolved repeatedly in isolated or marginal populations? I test whether sexual system variation reflects recent demographic isolation, historical founder events, or adaptation to environmental heterogeneity.
By comparing genomic structure across the range of C. nutans, I aim to determine whether hermaphroditic populations represent independently evolving lineages, recent responses to reduced connectivity, or environmentally structured populations within a broader species complex.
Linking genomics, landscapes, and herbarium collections
My work combines extensive field sampling with herbarium-based taxonomy and genome-scale sequencing. Current sampling spans Florida, Belize, Panama, Costa Rica, Mexico, and additional regions of Central America, with each collection designed to link reproductive observations, geographic locality, tissue samples, and voucher specimens.
Using whole-genome resequencing, I investigate patterns of population structure, demographic history, and lineage divergence. I use coalescent-based phylogenetics to infer relationships among populations, landscape genomic methods to estimate spatial connectivity, and demographic modeling to compare alternative histories of isolation, bottlenecks, expansion, and migration.
I also integrate environmental datasets, including climate and habitat variables, to ask whether genomic variation associated with sexual systems is better explained by landscape connectivity, environmental heterogeneity, or the interaction between the two.
Whenever possible, genomic datasets are linked to herbarium voucher specimens deposited in national and institutional collections. This ensures that genomic data remain connected to verifiable plant material and supports future systematic and taxonomic work in Catopsis.