Anna R Dornhaus

Anna R Dornhaus

Professor, Ecology and Evolutionary Biology
Professor, Entomology / Insect Science - GIDP
Professor, Psychology
Professor, Neuroscience
Professor, Neuroscience - GIDP
Professor, Cognitive Science - GIDP
Professor, BIO5 Institute
Primary Department
Contact
(520) 626-8586

Research Interest

Dr. Anna Dornhaus Ph.D., is Associate Professor of Ecology and Evolutionary Biology, Physiology and the BIO5 Institute. Dr. Dornhaus received her B.S. and Ph.D. in Zoology at the University of Würzburg and is currently an Associate Professor of Ecology & Evolutionary Biology at the University of Arizona. She specializes in the organization of groups as well as how collective behaviors emerge from the actions and interactions of individuals. Her model systems seek data in social insect colonies (bumble bees, honey bees and ants) in the laboratory and in the field, as well as using mathematical and individual-based modeling approaches. Dr. Dornhaus investigates mechanisms of coordination in foraging, collective decision-making, task allocation and division of labor. Dr. Dornhaus’ recent work has included the role of communication in the allocation of foragers to food sources; the evolution of different recruitment systems in different species of bees, and how ecology shapes these recruitment systems; house hunting strategies in ants; speed-accuracy trade offs in decision-making; and whether different group sizes necessitate different organizational strategies.

Publications

Blonder, B., & Dornhaus, A. (2011). Time-ordered networks reveal limitations to information flow in ant colonies. PLoS ONE, 6(5).

PMID: 21625450;PMCID: PMC3098866;Abstract:

Background: An important function of many complex networks is to inhibit or promote the transmission of disease, resources, or information between individuals. However, little is known about how the temporal dynamics of individual-level interactions affect these networks and constrain their function. Ant colonies are a model comparative system for understanding general principles linking individual-level interactions to network-level functions because interactions among individuals enable integration of multiple sources of information to collectively make decisions, and allocate tasks and resources. Methodology/Findings: Here we show how the temporal and spatial dynamics of such individual interactions provide upper bounds to rates of colony-level information flow in the ant Temnothorax rugatulus. We develop a general framework for analyzing dynamic networks and a mathematical model that predicts how information flow scales with individual mobility and group size. Conclusions/Significance: Using thousands of time-stamped interactions between uniquely marked ants in four colonies of a range of sizes, we demonstrate that observed maximum rates of information flow are always slower than predicted, and are constrained by regulation of individual mobility and contact rate. By accounting for the ordering and timing of interactions, we can resolve important difficulties with network sampling frequency and duration, enabling a broader understanding of interaction network functioning across systems and scales. © 2011 Blonder, Dornhaus.

Dornhaus, A., & Chittka, L. (1999). Evolutionary origins of bee dances. Nature, 401(6748), 38-.
Dornhaus, A., Klügl, F., Oechslein, C., Puppe, F., & Chittka, L. (2006). Benefits of recruitment in honey bees: Effects of ecology and colony size in an individual-based model. Behavioral Ecology, 17(3), 336-344.

Abstract:

Why do some social insects have sophisticated recruitment systems, while other species do not communicate about food source locations at all? To answer this question, it is necessary to identify the social or ecological factors that make recruitment adaptive and thus likely to evolve. We developed an individual-based model of honey bee foraging to quantify the benefits of recruitment under different spatial distributions of nondepleting resource patches and with different colony sizes. Benefits of recruitment were strongly dependent on resource patch quality, density, and variability. Communication was especially beneficial if patches were poor, few, and variable. A sensitivity analysis of the model showed that under conditions of high resource density recruitment could even become detrimental, especially if foraging duration was short, tendency to scout was high, or recruits needed a long time to find communicated locations. Colony size, a factor often suspected to influence recruitment evolution, had no significant effect. These results may explain the recent experimental findings that in honey bees, benefits of waggle dance recruitment seem to vary seasonally and with habitat. They may also explain why some, but not other, species of social bees have evolved a strategy to communicate food locations to nest mates.

Powell, S., & Dornhaus, A. (2013). Soldier-based defences dynamically track resource availability and quality in ants. Animal Behaviour, 85(1), 157-164.

Abstract:

Specialized defence traits and strategies are crucial in surviving enemy attacks and in resource acquisition. In numerous social insect lineages, soldiers function as specialized defence traits of the colony, but associated defence strategies are poorly known. The turtle ant Cephalotes rohweri is an obligate cavity-nesting ant with highly specialized soldiers. To maximize growth and reproduction, colonies must use their limited availability of soldiers to defend multiple cavities. Using laboratory experiments informed by field data, we addressed how soldier 'deployment' across cavities adjusts to changes in cavity availability and quality. From initial field-like conditions, soldier deployment to newly available cavities was rapid, stabilized quickly, and at least doubled the number of cavities defended by each colony. New cavities were defended by fewer soldiers than original cavities still in use. Nevertheless, when new cavities differed in size, an important quality metric, large cavities were used more often and defended by more soldiers than small cavities. Despite these dynamic responses, total soldier deployment to new cavities was limited to an approximately constant proportion (0.4) of overall soldier availability across colonies and resource contexts. Moreover, there was a significant positive relationship between total soldier deployment to new cavities (greater for larger colonies) and both the number of newly defended cavities and their average level of defence. These results demonstrate that colony-wide soldier deployment is dynamic, predictable and context sensitive but ultimately constrained by the availability of soldiers in the colony. Furthermore, the consistently lower number of soldiers in new cavities, which always limits the potential losses to enemies, is concordant with a 'conservative bet-hedging' life history strategy. Broadly, our findings show that a specialized soldier caste can be associated with a far more sophisticated defence strategy than previously recognized. This provides a more complete perspective on the evolution of soldier-based defences in insect societies. © 2012 The Association for the Study of Animal Behaviour.

Dornhaus, A., & Franks, N. R. (2008). Individual and collective cognition in ants and other insects (Hymenoptera: Formicidae). Myrmecological News, 11, 215-226.