Worker body size variation - a macroevolutionary approach
Worker polymorphism is found in ~15% of ant species and is often attributed to increased colony efficiency. However, we know little about the macroevolutionary patterns and effects on diversification. Using ancestral trait reconstructions and state dependent speciation extinction modeling we are asking where and when variable workers evolved and if they represent a key innovation (associated with increased diversification).
Scaling in functionally important traits
Previous work in the lab on the specialized trap jaw ants suggests that polymorphic workers have higher bite forces than comparably sized monomorphic congeners. I'm testing this pattern more broadly primarily using the harvester ant genus Pogonomyrmex.
Undergraduate Research - The University of Arizona
Bumble bee worker size polymorphism
Workers in bumble bee colonies have dramatic size variation, up to a 10-fold weight difference. Despite being poor at performing colony tasks, small workers are produced often throughout the colony's annual life. We tested the hypothesis that the ability to produce small workers (who require fewer resources to be produced and can survive starvation longer) is a safeguard to a variable resource environment. [Rivera and Dornhaus, in prep]
Bumble bee landing success on floral features
We investigated the effects of floral features, such as general orientation and presence of a labellum on the landing success of bumble bee foragers . We found that the benefit of these features on bumble bee landings are size dependent, in that larger bees landing on flowers with these features are more successful. [Rivera and Dornhaus, in prep]
Decision making in honey bee foragers
In order for honey bee colonies to rapidly and efficiently allocate forgers to resources, individuals need to constantly reevaluate their commitment to a resource. We look to see the relative importance of social or personal information in reevaluating a natural resource. Despite being shown to play a large role in manipulative experiments, we found little effects in natural foraging conditions. [Rivera, Donaldson-Matasci, Dornhaus, 2015]