Integrating Phenotypes and Phylogeography to Investigate Evolutionary Patterns in Widespread Bee Species

Restricted (Penn State Only)
- Author:
- Sandoval Arango, Stephania
- Graduate Program:
- Entomology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- May 21, 2024
- Committee Members:
- Gary Felton, Program Head/Chair
Margarita Lopez-Uribe, Chair & Dissertation Advisor
Thomas Baker, Major Field Member
Jesse Lasky, Outside Unit Member
Heather Hines, Major Field Member
Sara Hermann, Outside Field Member - Keywords:
- Orchid bees
Color variation
Ultraconserved Elements
Brood parasites
Behavior
Museum genomics - Abstract:
- Widespread species occur across a broad range of geographic and climatic conditions. Throughout these conditions, intraspecific phenotypic variation can occur as a result of ecological and evolutionary processes. Phylogeographic methods provide a powerful framework to understand the processes generating this variation through the investigation of spatial patterns of genetic and phenotypic diversity within a species. In this dissertation, I integrated phylogeographic approaches with phenotypic and life-history traits to investigate evolutionary patterns of widespread solitary and parasitic bees. Specifically, I used museum and field-collected specimens to characterize variation in color, morphology, and behavior of widespread Neotropical orchid bees, and North American cuckoo bees. In Chapter 1, I used phylogenomic data to explore whether color phenotypes in widespread Eulaema orchid bees correspond to independent lineages or represent polymorphic traits within species. I found incongruence between color morphs and evolutionary lineages within these species, indicating that color cannot be used to delimit species in this group of bees. In Chapter 2, I used genomic and phenotypic data to infer the phylogeographic patterns of a widespread brood parasitic bee, Triepeolus remigatus, and uncover the impact of historical abiotic and biotic factors on the spatial congruence of genetic and phenotypic variation. Similar to Chapter 1, I found deep phylogeographic breaks that were discordant with color variation in this species, while other phenotypic traits were partially concordant with lineages. The phylogeographic structure of T. remigatus was congruent with lineages previously recovered for the host, Xenoglossa (Peponapis) pruinosa. This indicates a potential impact of the host evolutionary history on the diversification of T. remigatus. Finally, in Chapter 3, I complemented the study of the evolutionary patterns of X. pruinosa and T. remigatus by investigating this host-parasite system from a behavioral perspective. I used circle-tube behavioral assays and direct observations at a nest aggregation of X. pruinosa to investigate whether there is aggression between both species, and to characterize the parasitic behavior of T. remigatus. I found a lack of aggression between host and parasitic bees, and interactions between the two species were primarily tolerant. Despite the absence of an aggressive response, T. remigatus entered nests while the host was foraging, with rapid visits without extensive inspection. These results indicate that behavioral responses to parasitism might exist inside the host nest and after parasitic visits, highlighting the need for further studies in this host-parasite system. Overall, my dissertation provides insight into the impact of abiotic and biotic factors on the ecology and evolutionary patterns of widespread bee species and highlights opportunities for further research to understand the evolution of host-parasite associations in bees.