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I currently work with Maelstrom Research, a group that addresses needs of large international epidemiological research networks to facilitate collaborative research through data documentation and harmonization, software and methods development, and knowledge dissemination. To learn more, visit: https://www.maelstrom-research.org/
Before this, I was involved in research on measuring emergent physiological processes that might be involved in aging and its negative health consequences. In general, this work suggest broadly conserved patterns of physiological dysregulation and aging across diverse primate species.
Much of my earlier research focused on the links between social behavior and ecology, using rodents as study systems. My dissertation work examined the structure of social interactions in a well-studied population of yellow-bellied marmots at a field site in the Colorado Rockies. In particular, we asked if and how age, sex, and kinship influence social connections, and if social attributes of individuals were associated with differences in reproductive success, stress hormones, or parasites. During graduate school, I also participated in a project in on examining reproductive correlates of social structure in degus, a rodent native to Chile. Subsequently, I worked on a project examining the links between individual behavioral variation, social interactions, and dispersal in Peromyscus mice, both in laboratory stocks and at a field site in northern California.
Another large part of my research has used insect model systems to explore questions about environmental effects on behavior and implications for sexual selection. In one project, we used experimental groups of water striders to examine the effects of individual behavior and social interactions on mating outcomes and sexual selection. In another project with tree weta, we asked how environmental variation in refuge size influenced the potential for sperm competition through effects on male-female encounters. Another study used a quantitative genetic experiment to ask if and how social experience during development influenced expression of adult behaviors and life history traits in sand field crickets.
I have also been involved in some interesting projects on captive animals, including zoo studies on behavior of African wild dogs and flamingos. Finally, I've been part of several conceptual papers about approaches and tools for the study of social behavior.
For more details on each of these topics, follow the links below:
Biomarkers of aging in primates
Individual traits, social context, and sexual selection in insect model systems
Behavioral studies in Peromyscus
Mating success in male and female water striders
Causes and consequences of social variation in marmots
Reproductive correlates of social structure in degus
Behavioral studies of captive animals
General aproaches to studying social behavior
Biomarkers of aging in primates
Aging is a complex process emerging from integrated physiological networks, and a major goal in the current biology of aging is to identify general mechanisms underlying the aging process in ways reflecting this complexity. Physiological dysregulation has been proposed as a driver of aging and its negative health effects, and evidence in humans supports this hypothesis. In particular, a recently proposed emergent measure of dysregulation, based on multivariate distance from a mean of many biomarkers, consistently increases with age and predicts health issues in different human populations. However, little research on this topic has been done outside of humans. We compared this measure of dysregulation in multiple species of nonhuman primates with humans and found that a strikingly similar pattern of dysregulation that increase with age and predicted mortality risk across most primates (Dansereau, Wey, et al. 2019). In a related study using the same primate datasets, we also found that the principal axis of variation in physiological biomarkers that was very similar across all primates studied and often correlated with age, although not usually with mortality (Wey, Roberge, et al. 2019). Together, these studies show that there are similar emergent physiological processes that can be detected across primates and that are likely involved in the aging process.
Individual traits, social context, and sexual selection in insect model systems
The Wellington tree weta (Hemideina crassidens) is a large nocturnal insect with strong sexual dimorphism (differences between males and females) and unusual male trimophism (three distinct sizes/forms of males). The size of refuges (called "galleries") is known to affect weta distribution and consequently the opportunity for sexual selection and selection on male weaponry. We extended this work to ask if gallery size was likely to affect multiple mating by females and the potential for sperm competition and found that smaller galleries created greater potential for both (Wey & Kelly 2018). This resulted in a pattern where variation in levels of relative sperm competition would likely reinforce variation mating success, i.e., males that were likely to have more mates were also likely to face fewer sperm competitors. The expression of phenotypes, including behavioral traits, are determined by a combination of genetic and environmental factors. In a lab experiment with sand field crickets (Gryllus firmus), we used a nested half-sib quantitative genetic design to ask how social density during development influenced expression of adult behaviors and life history traits. Somewhat surprisingly, we did not find consistent effects of social density during rearing or significant heritable components of adult behaviors, although we did find the expected effects of density and family on body mass and development time (Wey, Réale, & Kelly 2019). These results suggest that other factors are driving the observed variation in behaviors in this system.
These projects were done in conjunction with Clint Kelly and Denis Réale at the Université du Québec à Montréal (UQÀM), with the permission of the New Zealand Department of Conservation and with help from members of the Kelly lab. Funding for these projects (to Kelly and Réale) came from NSERC and the Canada Research Chairs Program.
Behavioral studies in Peromyscus
My previous postdoctoral research considered how individual behavioral variation and social interactions can influence dispersal (Wey & Mabry 2015; Wey, Spiegel, Montiglio, & Mabry 2015). This is part of an ongoing study on a population of brush mice (Peromyscus boylii), run by Karen Mabry (NMSU). The field portion takes place at Quail Ridge Reserve, part of the UC Davis Natural Reserve System for research and education, and uses the QRAAT automated tracking system. Specific thanks go to Shane Waddell and the QRAAT staff for technical aspects, and to Rebecca Kelley and other members of the Mabry lab for field assistance.
In another project, we asked if mating system or pace of life history was associated with species differences in behavioral profiles of several Persomyscus species. Our results suggested that mating system is associated with a number of behavioral differences and is a possible driver of behavioral diversity in this system (Wey, Vrana, & Mabry 2017). This work was done at the Peromyscus Genetic Stock Center, with additional help from Michael Felder, Kimberley Shorter, and Janet Crossland. Funding for these projects (to Mabry) came from the NSF.
My #UPGOERFIVE attempt to explain this idea using only the 1000 most common words. http://splasho.com/upgoer5/ (for reference see this xkcd comic https://xkcd.com/1133/)
Mating success in male and female water striders
To examine how individual characteristics and social factors interact to influence individual mating success and mating dynamics, we conducted a series of experiments using stream water striders (Aquarius remigis) tested in semi-natural experimental settings. Sexual selection studies commonly ask what variables influence male mating success, as a correlate of male fitness (e.g., Sih, Chang, & Wey 2014). However, female mating behavior, and specifically mating frequency, can influence the amount of sperm competition that males experience. Using multiple groups of striders held at two different sex ratios, we asked how male behaviors, female behaviors, and social environment potentially influenced what we called male mating exclusivity, or how little sperm competition a male experienced (Wey, Chang, Fogarty, & Sih 2015). As expected, there was a trade-off between how many females a male mated with and how long he spent with each female. However, counter to our predictions, males that mated more often did not, on average, have less exclusive matings (i.e., did not experience more sperm competition). Instead, when there were twice as many males as females (and more male-male competition for mating), males that mate more often also experienced less sperm competition. We also found that female behaviors and other males in the group affect male mating success, showing that many factors influence male mating success, besides his own behavior.
For females in many animal species, reproductive success can be limited by amount of food, rather than by number of mates, and in fact, mating more frequently can have negative effects. In these kinds of scenarios, female animals might make trade-offs between feeding more and experiencing more male mating attempts. In another analysis using the same system, we asked how female feeding and mating probabilities were influenced by female habitat use and activity and by the social environment (Wey, Chang, Montiglio, et al. 2015). Short-term behavioral state and local sex ratio predicted feeding, while mating also depended on female personality and hyper-aggressive males in the pool. Female water striders became active on the water before starting to feed, then once feeding, they were less active and more likely to start mating. Population sex ratio, which correlates with male harassment of females, strongly influenced average female behaviors, but correlations among female behaviors remained the same at different sex ratios. Overall feeding and mating dynamics emerged from individual behaviors and social factors interacting on different timescales.
Related work in this system shows that individual male behavioral variation in activity, aggression, and social plasticity can be maintained by correlational selection (Montiglio, Wey, Chang, et al., 2016a), and that multiple patterns of non-random mating according to body size and personality occur simultaneously (Montiglio, Wey, Chang, et al., 2016b). Some other recent research directions also explored the role of environment and group composition on emergent mating systems (Sih, Montiglio, Wey, et al. 2017; Montiglio, Wey, & Sih, 2017).
Studies on the water striders are part of ongoing research with Andy Sih at UC Davis. I was funded by an NSF Postdoctoral Research Fellowship in Biology. Additional thanks go to members of the Sih lab, Paul Lutes and Erik Hallen at the UC Davis Center for Aquatic Biology and Aquaculture, and to the UC Davis Natural Reserve System.
Causes and consequences of social variation in yellow-bellied marmots
There is remarkable diversity in the social organization of animals, both across and within species, and a major area of interest in behavioral ecology is to study the evolution and maintenance of social variation. While there are, typically, potential benefits of living in groups, such as increased predator detection and contact with potential mates, there are also a number of costs that often come with group living, including increased competition with other members of the group and increased risk of parasitism. Living socially brings individuals into contact more often, and social interactions are likely to occur. The interactions we observe might reflect patterns of conflict and cooperation between individuals, which can be driven by characteristics of individuals, by ecological or social factors, or a combination.
My graduate work focused on questions about how and why individuals have different social interactions, using a well-studied population of yellow-bellied marmots (Marmota flaviventris) at the Rocky Mountain Biological Laboratory in Gothic, CO. Individuals of this species can live in very different social environments, ranging from solitary animals to large colonies with >50 members. We were interested in building on long-term research on ecological effects on population and group size dynamics in this system to ask more detailed questions about why there are observed differences in social interactions, using a social network approach, in which we represented groups of marmots as networks of individuals connected by their social interactions (Wey, Blumstein, Shen, & Jordán 2008). We found that a number of individual-level characteristics influenced how affiliative (i.e., “friendly”) or aggressive marmots were and how marmots structured their social interactions (Wey & Blumstein 2010). Younger marmots were more important in maintaining friendly connections, while older marmots were more prominent initiators of aggression. Furthermore, marmots tended to be friendlier with closer relatives and other marmots of similar age, but also tended to fight more with closer relatives. Individual aggression in social groups and response to trapping were both repeatable within-individuals, but were not correlated with each other across individuals (Blumstein, Petelle, & Wey 2013).
Interestingly, aggressive behavior, and specifically the tendency to be “bullied” by other marmots seems to heritable while other types of social interaction are not (Lea, Blumstein, Wey, & Martin 2010). Young female marmots who were part of tighter networks of friendly interactions were less likely to disperse, while the amount or pattern of social connections did not predict which males dispersed (Blumstein, Wey, & Tang 2009). However, adult female marmots that had the most friendly connections were the ones who reproduced less, at least within a year, and adult male marmots that were the most aggressive and dominant were the ones that reproduced more (Huang, Wey, & Blumstein 2011; Wey & Blumstein 2012). Being better connected did not appear to have an individual cost of higher parasitism risk (Wey & Blumstein 2012), and there is variation in how marmot social group sizes were correlated with different types of parasites (Lopez, Wey, & Blumstein 2013). Stress hormone metabolite levels were not correlated with individual variation in social interactions (Wey & Blumstein 2012), but do predict overwinter survival of marmots (Wey, Lin, Patton, & Blumstein 2015) and affect foraging and vigilance behavior, in interaction with numerous other environmental and internal factors (Chmura, Wey, & Blumstein 2016).
All work on the marmots was done in conjunction with Dan Blumstein and the long-term marmot project through UCLA and the RMBL. I am involved in ongoing research projects focusing on the structural stability of social network motifs within and between years and on the use of white blood cell profiles as a measure of stress. My portions of the work were largely funded by a US Department of Education GAANN fellowship, an NSF GK-12 fellowship, and a UCLA Chancellor's Prize fellowship. I also received funding through the UCLA Department of Ecology and Evolution's Bartholomew Research Grant and Holmes O. Miller Fellowship, an RMBL Snyder Graduate Research Grant, and a UCLA Institute for Social Research GSR. Many many individuals to thank here, in addition to co-authors, but special thanks to my committee members--Peter Nonacs, Rick Grannis, and Peter Narins--and to Lucretia Olson, Janice Daniels, Adriana Maldonado-Chaparro, Julien Martin, and Jenn E. Smith for large parts in the marmot project and database.
Also check out the "Marmot Minutes" blog (http://marmots-ucla.blogspot.com/) for both up-to-date and archived notes from the project, including some older posts by me.
Social structure and behavioral variation in degus
Animals living together in groups can experience both reproductive benefits or conflicts of being around others. Female degus (Octodon degus) nurse pups communally, but groups with more females also have fewer pups per female. In a field study (Wey, Burger, Ebensperger, & Hayes 2013), we characterized social connections in a population of female degus and hypothesized that, if there was social cooperation, groups with stronger social connections among females would be associated with more pups per female, while if there was social conflict, groups with uneven social connections (mixes of strong and weak connections) among females would be associated with fewer pups per female. Female degus had stronger and more stable social connections than males, and females had stronger connections with each other when they were nursing pups. However, groups of females with stronger connections did not have more pups per female. Groups with uneven social connections had fewer pups per female, which might reflect negative effects of group instability.
More recently, we found that adult degus show consistent individual differences in behavior (animal personality), that different behavioral traits can be correlated (behavioral syndromes), and that social preferences based on personality might structure degu social networks (Chock, Wey, Ebensperger, & Hayes 2017).
My part in this research was originally funded by a Sigma Xi GIAR and NSF IRES (to Loren Hayes), and the degu project is part of ongoing research by Luis Ebensperger (PU Católica de Chile) and Loren Hayes (U Tenn Chattanooga). Special thanks to members of that year's degu crew (Rachel Chock, Morgan Elfelt, Michael Lough-Stevens, Monica Stewart, Raúl Sobrero, and the nicest man in the world, Juan).
I maintained a mini-photoblog of fieldwork and general life while I was in Chile, which is at "Un fotoblog desde Chile" http://tww-fotoblog.blogspot.com/.
Behavioral studies of captive animals
Captive populations of animals, such as those in zoos, may provide opportunities to collect unusually detailed data, especially on animals that are endangered, cryptic, or otherwise difficult to study in the wild. By adding to our understanding of what influences behaviors such as reproduction and aggression, observations of zoo animals can also aid in conservation, welfare, and other applied efforts. I have had the opportunity to be part of two studies using behavioral data collected on zoo populations, and while understanding that there are limits to what we can generalize from these conditions, there are many interesting opportunities for researchers to learn from captive populations.
Artificial conditions can enhance or decrease breeding success, and it is critical to understand what affects reproductive success of endangered animals in captivity. As an intern at the Bronx Zoo, NY, I assisted in a behavioral study on the unusual event of two female African wild dogs giving birth and rearing two litters of pups at the same time, which was accompanied by a dominance reversal between the two females (Thomas, Powell, Fergason, et al. 2006). This situation typically would not happen in the wild, and at the time, there was relatively low success rate of breeding this species in captivity. Thus we wanted to describe the factors that may have contributed to successful rearing of all the pups and the reversal of dominance without high levels of aggression, which are both of great interest for captive breeding and animal welfare. My participation in this project was made possible through the Wildlife Conservation Society's Robert C. Engel Mammalogy Intern Program at the Bronx Zoo and supervised by David Powell (WCS) and Patrick Thomas (WCS).
(Photo credit: Wikimedia commons)
Aggression is common when individuals compete for resources, including food and breeding territories. Captive populations are often held at relatively high densities, which can increase aggression, and it is important to understand the causes of aggression to prevent unnecessary injuries or stress under these conditions. In a study of American flamingoes at the Audubon Zoo in New Orleans, LA, we examined patterns of aggression during the breeding season, spanning the periods of courtship through pair bond formation (Hinton, Bendelow, Lantz, et al. 2013). During pair bond formation, there was an overall increase in aggression and relatively high aggression by older males, suggesting that competition for nesting sites and resources were higher than competition for mates and that watching for negative effects of aggression is especially important in this stage of the breeding season. In a follow-up study on patterns of aggression and mating across years, we found no obvious systematic impact of a simultaneous removal/introduction event on group social structure; furthermore, individuals were consistent in their aggression across years, as were identities of mated pairs (Frumkin, Wey, Exnicios, et al. 2016). Thus social patterns of this captive population of flamingos seemed to show consistency across years. This work is part of an ongoing project in Jordan Karubian's lab at Tulane University.
Pretty aggressive in pink. (Photo credit: Wikimedia commons)
General approaches to studying social behavior
I have been involved in multiple projects aimed at advancing conceptual and practical tools for the study of animal social behavior. In particular, interest in applying social network analysis to questions about animal behavior (Wey, Blumstein, Shen, & Jordán 2008; Wey 2015; Croft, Darden, & Wey 2016) is part of a broader interest in finding accurate ways to describe, analyze, and compare social behavior that we observe in the real world. Social interactions and networks can be highly dynamic, and developing and testing methods for better understanding of realistic network dynamics is currently an area of intense interest and growth (Blonder, Wey, Dornhaus, et al. 2012; Sih & Wey 2013). Additionally, integrating understanding of proximate mechanisms (e.g., endocrine, neurological, and genetic) and expanding studies in non-model organisms continue to represent exciting and challenging directions for broadening our understanding of social behavior (Blumstein, Ebensperger, Hayes, et al. 2010). Social interactions can also influence animal movement and ecology. For example, individual personality is likely to interact with social context to influence dispersal decisions (Wey, Spiegel, Montiglio, & Mabry 2015). Another study using proximity loggers to continuously track free-living sleepy lizards (Tiliqua rugosa) also suggests that habitat structure will affect animal movements and, consequently, social networks (Leu, Farine, Wey, et al. 2016).
Several workshops and symposia that have been critical for generating collaborations and ideas include: an NSF-funded US–South America Workshop on "Intraspecific variation and social systems: explaining variation based on neuroendocrine and genetic mechanisms" in Santiago, Chile (2009), organized by Dan Blumstein (UCLA) and Loren Hayes (U Tenn Chattanooga); the "Symposium on network science in biological, social, and geographic systems" at University of Wyoming at Laramie (2012), organized by Dave McDonald (U Wy Laramie) and Andrew Edelman (UWG); and the NIMBioS exploratory workshop on "Animal social networks" in Knoxville, TN (2014), organized by Dave McDonald (UWy Laramie), Tanya Berger-Wolf (UIC), Jennifer Fewell (ASU), Amiyaal Ilany (NIMBioS, U Penn), Bryan Shader (U Wy Laramie), and Tina Wey (NMSU, UC Davis).
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