21 Jan 2011:
Tom Richardson, University of West England and Bristol University
Individual movement and space use in ants
Social insect colonies face the challenging task of coordinating the actions of large numbers of spatially dispersed individuals, that possess only incomplete or local information. These organisational challenges exist both outside the nest - in foraging, or territorial defence - and within it- for example when performing housekeeping tasks such as tending to brood. Using case-studies, this talk will examine how social insect societies have solved these challenges. The first case study will be that of foraging recruitment by "tandem running". We will examine how the colony uses this technique to ensure that valuable information is not lost, but instead is amplified throughout the society. Our second case study is that of individual movement within the nest. Whilst it has long been known that the individuals in social insect colonies specialise on a particular task subset, and so achieve a division of labour, the concomitant division of space has only recently begun to attract attention. We will concentrate on how home-range analysis - traditionally used in vertebrate ecology - can be used to describe this spatial division of labour.
04 Feb 2011: Laurence Gesquiere
The effect of environmental and social factors on male baboon physiology
Organisms are exposed in their daily life to numerous stressors such as environmental, social or even psychological. In the first part of the talk I will focus on the effects of environmental factors on animal reproduction and physiology. Environmental factors have a strong impact on female fertility but their effect on male fertility is less clear. Taking advantage of our long-term study of wild baboons in Amboseli, Kenya, we examined the effects of the dry season and the high ambient temperatures on male baboon physiology. Previous studies by our group suggested that female baboon physiology and reproduction were affected by Amboseli's harsh environmental conditions. Our goal is to see if males are more resistant than females or similarly challenged to those environmental conditions. The second part of the talk will focus on the effect of dominance rank on male physiology. Being high-ranking in a society has numerous benefits such as high reproductive success but those benefits may come to a cost. Indeed some studies have suggested that higher-ranking individuals have higher stress hormone levels than lower-ranking ones. However this view is not unanimous and some studies have suggested just the opposite. We propose to examine which of the high or low-ranking males have higher glucocorticoids and testosterone levels and how hierarchy stability may be affecting these relationships.
11 Feb 2011: Corinne Kendall
The influence of ecological and behavioral factors on habitat use and foraging in an avian scavenger guild
Interspecific variations in habitat selectivity can enable coexistence, often creating a despotic distribution. Among the diverse guild of avian scavengers, habitat use and foraging are likely to be influenced by ecological and behavioral factors. Using transects and carcass counts, the significance of intraspecific aggregation, wildlife density, and human disturbance on scavenger habitat use and foraging within and around Masai Mara National Reserve was assessed. Findings provide evidence of a despotic distribution where subordinate species, such as Tawny eagles and Hooded vultures, have lower abundance in areas of high quality and higher tolerance of human disturbance, while socially dominant species, such as Ruppell’s vulture and African white-backed vulture, can monopolize areas of high quality. Solitary species with high dominance, such as the Lappet-faced vulture, also showed the greatest avoidance of human disturbance. In addition, foraging behavior of the most highly social species, the African white-backed vultures, was strongly influenced by their ability to coalesce in a given area rather than by ecological factors. Results suggest that all species are able to feed in areas of human settlement and may thus be susceptible to poisoned carcasses and that highly social species, such as African white-backed vultures, may be vulnerable to Allee effects as their overall abundance and wildlife densities declines.
18 Feb 2011: Simon Leblanc
Analysis of high quality sheep data
A team composed of Hamed Haddadi, Andrew J. King, Alison P. Wills, Damien Fay, John Lowe, A. Jennifer Morton, Stephen Hailes, and Alan Wilson have accumulated in March 2010 a dataset of high quality where they tracked Merino sheep (Ovis aries) for several days using a brilliant cocktail of high-tech devices (GPS, magnetometer, accelerometer). Individual physical properties as well as some elements of behavior were also recorded for each sheep. The configuration varies from a single large group to small subgroups. There are also special events like feeding and dog herding... This talk will present their dataset and some very preliminary analysis with a focus on state transitions (from resting to moving). The goal is clearly to get early feedback and ideas from the audience in order to get started in the good direction.
25 Feb 2011: Andy Dobson
Fission-fusion dynamics of social carnivores: Possible impacts of pathogens
Social carnivores live in groups whose structure forms a tension between the need to locate and acquire food, and the stresses associated with sharing it. The former creates Allee effects and make it advantageous to live in a group, the latter creates a cost to group living. Using data from Serengeti Wild Dogs and Yellowstone wolves, I will develop a relatively simple model for a population that lives in social groups driven by fission-fusion dynamics. If time permits, I'll then add in different types of pathogen and examine how the pathogen modifies the social dynamics of its hosts. This is joint work done with Emily Almberg and Peter Hudson of Yellowstone Wolf Project and Penn State University and Emannuel Masenga of Serengeti Wild Dog project.
04 Mar 2011: Carey Nadell
A fitness trade-off between local competition and dispersal in Vibrio cholerae biofilms
Bacteria commonly grow in surface-bound communities, termed biofilms, where they secrete extracellular polymeric substances (EPS) that bind bacterial collectives together. A fundamental issue regarding biofilms is whether the EPS matrix serves as a public good that benefits neighboring cells, or as a weapon deployed by bacteria to displace other strains in the struggle for limited space and nutrients. Using the model organism Vibrio cholerae, we show that EPS production, though costly, confers competitive dominance against EPS-deficient cells within biofilms. However, this advantage carries an ecological cost: impaired dispersal. Our study defines a trade-off between clashing competitive abilities on different spatial scales and suggests that V. cholerae has evolved to balance this trade-off with regulatory mechanisms, including quorum sensing, that fine-tune the timing of EPS production.
11 Mar 2011: Noam Miller
Schooling and shoaling in zebrafish
Many species, across a wide range of genera, live or forage in groups. Groups of fish are called shoals and shoals exhibiting polarized, synchronized movement are called schools. I will present some work exploring this distinction empirically using groups of zebrafish. Schools and shoals represent distinct levels of organization of fish groups and reliably differ on several behavioral dimensions. The transition from one mode to the other also follows a well-defined pattern of behavioral changes. Modelers of collective motion have suggested that the degree of organization depends in part on the density of the group and I will show some data that addresses this, too.
22 Mar 2011: Isabel Behncke, University of Oxford
Jungle joy: Play behavior in the wild bonobos of Wamba, DR Congo
Play behavior in birds and mammals is widespread amongst infants and juveniles, yet almost universally ceases when individuals reach maturity. There are however a few species in which individuals continue to play into adulthood. This ‘biological exception’ seems to occur in the species that are characterized as having ‘social brains’, i.e., taxa demonstrating complex sociality and cognition. Existing play literature presents play as ‘preparation for adulthood’. I argue that the existence of play in adults is intimately linked to the evolution of intense sociality and complex cognition. I set out to see whether adult play would be found in wild bonobos (Pan paniscus). Bonobos, together with chimpanzees, are our closest living relatives yet we know relatively little about them. I spent 7 months following E-1 group (28 individuals) in Wamba, DR Congo. The Japanese research camp of Wamba was established by Kano in the early 70’s, and represents the longest-running bonobo research site. Play in adults was surprisingly common, with adult-infant or adult-juvenile play occurring on a daily basis. Unexpectedly, I found the adult males to be particularly playful, not only engaging in daily play with immature individuals, but also sometimes initiating playful interactions. Adult-adult play was also observed (albeit at lower frequencies), both with and without the presence of infants. Sexual activity happened often in the context of play, in all sex and age class combinations. Findings will be discussed in the context of the evolution of social brains, neoteny, social tolerance and play as protean behavior.
01 Apr 2011: Patty Chen
Perspectives on endogenous estrogens in a free-living nonhuman male primate
Our understanding of sex steroid hormones continues to expand beyond simply thinking of androgens (specifically testosterone) as hormones for males and estrogens as hormones for females. Males and females rely on both sets of steroid hormones for normal functioning. For instance, estrogens play an important role in mediating mammalian male physiology and behavior. I will introduce and present my undergraduate senior thesis work-in-progress under the guidance of Jeanne Altmann and Laurence Gesquire with additional support from Patrick Onyango and Niki Learn. I address the role of estrogens in the lives of adult and subadult male baboons in relation to both our current knowledge on male baboons as well as to other nonhuman primate males.
08 Apr 2011: Stephanie Eby
Ferocious predators and yummy food influence herbivore preference for burned areas
Numerous studies have found that certain herbivore species prefer burned areas, but the reason for this preference is unclear. Burning causes increases in plant nutrients which may explain the preference, but it also reduces vegetation height and increases visibility, thereby potentially reducing predation risk. Additionally, the reason(s) for burned area preference might differ between herbivore species. I will present results from work testing how vegetation height, biomass to necromass ratio, and leaf nutrients influence the preference for burned areas of different herbivore species in Serengeti National Park, Tanzania. Additionally, I will discuss how burning influences the distribution of a predator species the lion (Panthera leo).
15 Apr 2011: Sarah McKay Strobel
Hearing capabilities of the American sand lance and implications for sound use in humpback whale foraging strategies
Most research attempting to decode the ecosystem of marine mammals ignores the influence that prey dynamics and physiology may have on foraging strategies. Furthermore, the hearing capabilities of fish species, widely considered nonexistant until the early 20th century, are still understudied, with published audiograms for less than 1% of extant species. A focus on acoustics research is essential in a marine environment where sound can often be more reliable than sight, especially as anthropogenic ocean noise continues to rise. My thesis research focused on the hearing abilities of Ammodytes americanus, a species incredibly important to over 100 consumer species, including birds and cetaceans in the northwestern Atlantic. One such predator, the humpback whale, has recently been recorded as emitting broadband calls (termed 'megapclicks') during nighttime foraging reminiscent of toothed whales' echolocation signals. By constructing an audiogram and simulating these megapclicks, I discovered that A. americanus can hear low frequency energy in the clicks, which presents exciting opportunities both to challenge the long-held consideration that baleen whales are incapable of echolocation and speculate if the calls serve prey manipulation or echolocation purposes.
22 Apr 2011: Jacinta Beehner, University of Michigan
Minimizing reproductive loss: Female counterstrategies to infanticide in a wild primate
In a number of mammalian species, sexually selected infanticide by males is a threat to female reproductive fitness. In such species, females often exhibit counterstrategies to protect their reproductive investment. Evidence has been mounting that infanticide by males is the greatest cause of infant mortality in a population of geladas (Theropithecus gelada) living in the Simien Mountains National Park, Ethiopia. Consequently, we hypothesized that females at greatest risk for infanticide, pregnant and lactating females, should exhibit one or more physiological or behavioral counterstrategies following the arrival of a novel male. To test this hypothesis, we used 5 years of demographic data across 28 male replacements, supplemented by ovarian hormone data (extracted non-invasively from fecal samples) from 7 of these replacements. We found indirect and direct support for our hypothesis, and these counterstrategies will be discussed in the talk.
29 Apr 2011: Simon Garnier
Living architecture: Bridge construction by army ants
The neotropical army ant Eciton burchellii is mostly known for its spectacular group raids. Everyday, up to 200,000 workers are involved in a collective hunt to feed a colony that can contain more than 1,000,000 individuals. This collective behavior generates a massive amount of traffic that must be handled efficiently in order to facilitate the flow of captured prey toward the colony. On rugged terrains, some workers spontaneously assemble with each other in order to plug holes and bridge gaps, therefore smoothing the path for prey-carrying ants. Very little is known however about the emergence of these structures and the factors that regulate their size and shape. Here, I present the first quantitative study of bridge construction in army ants. I will show results about the dynamics of the building process, as well as data on the individual behavior of ants during the construction. I will also introduce a pseudo-spatial model that reproduces the main characteristics of the building process and I will use it to investigate the changes in the bridge structure in response to variation in the ant traffic.
06 May 2011: Jennifer Shieltz
Hybrid zebras: A horse of a different color?
Hybridization between closely related species has been observed in nearly all major plant and animal taxa, both in captivity and in the wild. The effect of hybridization on phenotype can be quite variable depending on the levels of genetic introgression and differences in gene expression. Particular traits may be determined by one parent only, or be intermediate between the two. Hybrid individuals generally posses physical characteristics of both parents, while behavior of hybrids may vary depending on the complexity of gene interaction and the extent to which behaviors are learned from one species or the other. Studying hybrid behavior can therefore be an opportunity to separate environmental or learned traits from genetic ones.
Recently, the first evidence of natural hybridization between Grevy’s and Plains zebras was reported from an area of range overlap in central Kenya, where hybridization has not been known to occur until the past decade (Cordingley et al., 2009). All hybrids have a Grevy’s zebra father and plains zebra mother. Because they are born to plains zebra mothers, hybrids have been raised exclusively in the plains zebra society. Therefore, any behavioral differences between hybrids and plains zebra may result from genetic influences of their Grevy’s zebra fathers, but currently little is known about the behavior of these hybrids relative to both parental species. Here I discuss the current status of the hybrid population and present preliminary finding on the behavior and social organization of these hybrids.
13 May 2011: Stephen Shepherd
Sighted individuals look where they attend, and next intend, to act. Many animals, including ourselves, use this observed gaze as a behavioral cue. Gaze following by humans arises in a split second, independent of task relevance, and appears to be a crucial foundation for joint attention, language development, and theory of mind. Nevertheless, human and nonhuman animals share basic gaze-following behaviors, suggesting the foundations of human social cognition may also be present in nonhuman brains. I'll outline current issues in gaze-following behavior and summarize my own work on gaze following behavior and mechanisms in primates.
20 May 2011: Catherine Markham
White Monkey Syndrome and presumptive copper deficiency in wild baboons
Copper (Cu) is a trace mineral so important for proper growth and development that deficiencies significantly compromise the health and survivorship of afflicted individuals. In this talk, I’ll discuss symptoms observed in wild savannah baboons (Papio cynocephalus) that are consistent with Cu deficiency and, more specifically, with a disorder referred to as white monkey syndrome (WMS) in laboratory primates. The first part of my presentation will focus on recent research using 2001-09 data from the Amboseli Baboon Project to (1) evaluate whether Cu deficiency in our study population may have been induced by zinc (Zn) or molybdenum (Mo) toxicity, and (2) examine cumulative rainfall during the perinatal period as an ecological factor distinguishing infants afflicted with WMS from non-WMS infants. The second part of my presentation will summarize our plans for future research and outline key questions we hope to address in the year to come.