Publications by year
Nichols HJ, Arbuckle K, Sanderson JL, Vitikainen EIK, Marshall HH, Cant M, Wells D (In Press). A double pedigree reveals genetic but not cultural inheritance of cooperative personalities in wild banded mongooses. Ecology Letters
Marshall H, Johnstone R, Thompson F, Nichols H, Wells D, Joe H, Kalema-Zikusoka G, Sanderson J, Vitikainen E, Blount J, et al (In Press). A veil of ignorance can promote fairness in a mammal society. Nature Communications
Sheppard CE, Inger R, Macdonald R, Barker S, Jackson A, Thompson F, Vitikainen E, Cant MA, Marshall H (In Press). Intragroup competition predicts individual foraging specialisation in a group-living mammal. Ecology Letters
Preston B, Thompson FJ, Ellis S, Kyambulima S, Croft D, Cant M (In Press). Network-level consequences of outgroup threats in banded mongooses: grooming and aggression between the sexes. Journal of Animal Ecology
Inzani E, Marshall H, Thompson F, Kalema-Zikusoka G, Cant M, Vitikainen E (In Press). Spontaneous abortion as a response to reproductive conflict in the banded mongoose. Biology Letters
Blount J (In Press). Untangling the oxidative cost of reproduction: an analysis in wild banded mongooses. Ecology and Evolution
Padget RFB, Cant MA, Thompson FJ (2023). Us, them, and the others: Testing for discrimination amongst outgroups in a single‐piece nesting termite. <i>Zootermopsis angusticollis</i>. Ecology and Evolution, 13(3).
Green PA, Thompson FJ, Cant MA
(2022). Fighting force and experience combine to determine contest success in a warlike mammal. Proceedings of the National Academy of Sciences
Fighting force and experience combine to determine contest success in a warlike mammal
. Conflicts between social groups or “intergroup contests” are proposed to play a major role in the evolution of cooperation and social organization in humans and some nonhuman animal societies. In humans, success in warfare and other collective conflicts depends on both fighting group size and the presence and actions of key individuals, such as leaders or talismanic warriors. Understanding the determinants of intergroup contest success in other warlike animals may help to reveal the role of these contests in social evolution. Using 19 y of data on intergroup encounters in a particularly violent social mammal, the banded mongoose (
. Mungos mungo
. ), we show that two factors, the number of adult males and the age of the oldest male (the “senior” male), have the strongest impacts on the probability of group victory. The advantage conferred by senior males appears to stem from their fighting experience. However, the galvanizing effect of senior males declines as they grow old until, at very advanced ages, senior males become a liability rather than an asset and can be evicted. As in human conflict, strength in numbers and the experience of key individuals combine to determine intergroup contest success in this animal society. We discuss how selection arising from intergroup contests may explain a suite of features of individual life history and social organization, including male eviction, sex-assortative alloparental care, and adult sex ratio.
Sankey DWE, Hunt KL, Croft DP, Franks DW, Green PA, Thompson FJ, Johnstone RA, Cant MA
(2022). Leaders of war: Modelling the evolution of conflict among heterogeneous groups. Philosophical Transactions of the Royal Society B: Biological Sciences
Leaders of war: Modelling the evolution of conflict among heterogeneous groups
War, in human and animal societies, can be extremely costly but can also offer significant benefits to the victorious group. We might expect groups to go into battle when the potential benefits of victory (V) outweigh the costs of escalated conflict (C); however, V and C are unlikely to be distributed evenly in heterogeneous groups. For example, some leaders who make the decision to go to war may monopolize the benefits at little cost to themselves ( exploitative leaders). By contrast, other leaders may willingly pay increased costs, above and beyond their share of V ( heroic leaders). We investigated conflict initiation and conflict participation in an ecological model where single-leader multiple-follower groups came into conflict over natural resources. We found that small group size, low migration rate and frequent interaction between groups increased intergroup competition and the evolution of exploitative leadership, while converse patterns favoured increased intragroup competition and the emergence of heroic leaders. We also found evidence of an alternative leader/follower shared effort outcome. Parameters that favoured high contributing heroic leaders, and low contributing followers, facilitated transitions to more peaceful outcomes. We outline and discuss the key testable predictions of our model for empiricists studying intergroup conflict in humans and animals. Abstract
Ellis S, Cant M, Weiss M, Brent L, Meniri M, Thompson F, Croft D
(2022). Patterns and consequences of age-linked change in local relatedness in animal societies. Nature Ecology and Evolution
Patterns and consequences of age-linked change in local relatedness in animal societies
The ultimate payoff of behaviours depends not only on their direct impact on an individual but also on the impact on their relatives. Local relatedness – the average relatedness of an individual to their social environment – therefore has profound impacts on social and life history evolution. Recent work has begun to show that local relatedness has the potential to change systematically over an individual’s lifetime, a process called kinship dynamics. However, it is unclear how general these kinship dynamics are, whether they are predictable in real systems and their impacts on behaviour and life history evolution. In this study, we combine modelling with data from real systems to explore the extent and impact of kinship dynamics. We use data from seven group-living mammals with diverse social and mating systems to demonstrate not only that kinship dynamics occur in animal systems, but also that the direction and magnitude of kinship dynamics can be accurately predicted using a simple model. We use a theoretical model to demonstrate that kinship dynamics can profoundly impact lifetime patterns of behaviour and can drive sex differences in helping and harming behaviour across the lifespan in social species. Taken together this work demonstrates that kinship dynamics are likely to be a fundamental dimension of social evolution, especially when considering age-linked changes and sex differences in behaviour and life history. Abstract
Green PA, Preston EFR, Nicholl MH, Croft DP, Thompson FJ, Cant MA
(2021). Collective defence and behavioural homogeneity during simulated territorial intrusions in banded mongooses (Mungos mungo). ETHOLOGY
(10), 886-896. Author URL
Padget RFB, Thompson FJ (2021). Marking through molts: an evaluation of visible implant elastomer to permanently mark individuals in a lower termite species. Ecology and Evolution, 11(18), 12834-12844.
Preston EFR, Thompson FJ, Kyabulima S, Croft DP, Cant MA
(2021). The dynamics of social cohesion in response to simulated intergroup conflict in banded mongooses. ECOLOGY AND EVOLUTION
(24), 18662-18675. Author URL
Thompson F, Hunt K, Wright K, Rosengaus R, Cole E, Birch G, Maune A, Cant M
(2020). Data from: Thompson et al Who goes there? Social surveillance as a response to intergroup conflict in a primitive termite.
Data from: Thompson et al Who goes there? Social surveillance as a response to intergroup conflict in a primitive termite
Data supporting Thompson et al Biology Letters Abstract
Thompson F, Johnstone R, Cant M, Cram D
(2020). Data supporting Johnstone, Cant, Cram & Thompson (2020) Exploitative leaders incite intergroup warfare in a social mammal.
Data supporting Johnstone, Cant, Cram & Thompson (2020) Exploitative leaders incite intergroup warfare in a social mammal
This data supports the following publication:Rufus A. Johnstone, Michael A. Cant, Dominic L. Cram & Faye J. Thompson (2020) Exploitative leaders incite intergroup warfare in a social mammal. Proceedings of the National Academy of Sciences.Please read the "Read Me.txt" file for a full description of the data contained in each data set Abstract
Johnstone RA, Cant M, Dominic C, Thompson F (2020). Exploitative leaders incite intergroup warfare in a social mammal. Proceedings of the National Academy of Sciences of USA
Wells DA, Cant MA, Thompson FJ, Marshall HH, Vitikainen EIK, Hoffman JI, Nichols HJ
(2020). Extra-group paternity varies with proxies of relatedness in a social mammal with high inbreeding risk. Behavioral Ecology
Extra-group paternity varies with proxies of relatedness in a social mammal with high inbreeding risk
. Behavioral mechanisms for avoiding inbreeding are common in the natural world and are believed to have evolved as a response to the negative consequences of inbreeding. However, despite a fundamental role in fitness, we have a limited understanding of the cues that individuals use to assess inbreeding risk, as well as the extent to which individual inbreeding behavior is repeatable. We used piecewise structural equation modeling of 24 years of data to investigate the causes and consequences of within- versus extra-group paternity in banded mongooses. This cooperatively breeding mammal lives in tight-knit social groups that often contain closely related opposite-sex breeders, so inbreeding can be avoided through extra-group mating. We used molecular parentage assignments to show that, despite extra-group paternity resulting in outbred offspring, within-group inbreeding occurs frequently, with around 16% litters being moderately or highly inbred. Additionally, extra-group paternity appears to be plastic, with females mating outside of their social group according to individual proxies (age and immigration status) and societal proxies (group size and age) of within-group inbreeding risk but not in direct response to levels of within-group relatedness. While individual repeatability in extra-group paternity was relatively low, female cobreeders showed high repeatability, suggesting a strong constraint arising from the opportunities for extra-group mating. The use of extra-group paternity as an inbreeding avoidance strategy is, therefore, limited by high costs, opportunity constraints, and the limited reliability of proxies of inbreeding risk.
Thompson F, Hunt K, Wright K, Rosengaus R, Cole E, Birch G, Maune A, Cant M
(2020). Who goes there? Social surveillance as a response to intergroup conflict in a primitive termite. Biology Letters
Who goes there? Social surveillance as a response to intergroup conflict in a primitive termite
Intergroup conflict has been suggested as a major force shaping the evolution of social behaviour in animal groups. A long-standing hypothesis is that groups at risk of attack by rivals should become more socially cohesive, to increase resilience or protect against future attack. However, it is usually unclear how cohesive behaviours (such as grooming or social contacts) function in intergroup conflict. We performed an experiment in which we exposed young colonies of the dampwood termite, Zootermopsis angusticollis, to a rival colony while preventing physical combat with a permeable barrier. We measured social contacts, allogrooming and trophallaxis before, during and after exposure. Termites showed elevated rates of social contacts during exposure to a rival compared to the pre-exposure phase, but rates returned to pre-exposure levels after colonies were separated for 9 days. There was evidence of a delayed effect of conflict on worker trophallaxis. We suggest that social contacts during intergroup conflict function as a form of social surveillance, to check individual identity and assess colony resource holding potential. Intergroup conflict may increase social cohesion in both the short and the long term, improving the effectiveness of groups in competition. Abstract
Birch G, Cant MA, Thompson FJ
(2019). Behavioural response of workers to repeated intergroup encounters in the harvester ant Messor barbarus. Insectes Sociaux
Behavioural response of workers to repeated intergroup encounters in the harvester ant Messor barbarus
The evolution of cooperation in animal societies is often associated with the evolution of hostility towards members of other groups. It is usually predicted that groups under attack from outsiders should respond by becoming more cohesive or cooperative. However, the responses of individuals to real or simulated intergroup encounters vary widely, for reasons that are poorly understood. We tested how groups of workers of the harvester ant, Messor barbarus, responded to exposure to members of a different colony versus members of their own colony, and how previous exposure to an intruder affected the intensity of the within-group response. We found that workers increased in activity and had more contact with one another immediately following exposure to an ant from a different colony, but also showed a similar behavioural response to presentations involving an ant from their own colony. However, exposure to an intruder from a different colony resulted in much stronger behavioural responses to a second intruder, encountered shortly afterwards. Our results are consistent with studies of social vertebrates which suggest that exposure to intruders results in increased social cohesion. Our results also show that exposure to an intruder primes group members to respond more strongly to future intrusions. Our findings highlight a disconnect between the assumptions of theoretical models which study the effect of intergroup conflict on social evolution over many generations, and the short-term behavioural responses that are the usual focus of studies of intergroup conflict in insects and vertebrates. Abstract
Vitikainen E, Thompson F, Marshall H, Cant MA (2019). Live long and prosper: durable benefits of early-life care in banded mongooses. Philosophical Transactions B: Biological Sciences
Marshall H, Inger R, Jackson AL, McDonald R, Thompson F, Cant MA (2019). Stable isotopes are quantitative indicators of diet and trophic niche. Ecology Letters
Marshall HH, Griffiths DJ, Mwanguhya F, Businge R, Griffiths AGF, Kyabulima S, Mwesige K, Sanderson JL, Thompson FJ, Vitikainen EIK, et al
(2018). Data collection and storage in long-term ecological and evolutionary studies: the Mongoose 2000 system. PLoS One
Data collection and storage in long-term ecological and evolutionary studies: the Mongoose 2000 system.
Studying ecological and evolutionary processes in the natural world often requires research projects to follow multiple individuals in the wild over many years. These projects have provided significant advances but may also be hampered by needing to accurately and efficiently collect and store multiple streams of the data from multiple individuals concurrently. The increase in the availability and sophistication of portable computers (smartphones and tablets) and the applications that run on them has the potential to address many of these data collection and storage issues. In this paper we describe the challenges faced by one such long-term, individual-based research project: the Banded Mongoose Research Project in Uganda. We describe a system we have developed called Mongoose 2000 that utilises the potential of apps and portable computers to meet these challenges. We discuss the benefits and limitations of employing such a system in a long-term research project. The app and source code for the Mongoose 2000 system are freely available and we detail how it might be used to aid data collection and storage in other long-term individual-based projects. Abstract
. Author URL
Sheppard CE, Marshall H, Inger R, Thompson F, Vitikainen E, Barker S, Nichols HJ, Wells DA, McDonald R, Cant MA, et al (2018). Decoupling of genetic and cultural inheritance in a wild mammal. Current Biology
Thompson F, Cant MA (2018). Dynamic conflict among heterogeneous groups: a comment on Christensen and Radford. Behavioral Ecology
Hares MC, Vitikainen EIK, Marshall HH, Thompson FJ, Blount JD, Cant MA
(2018). Telomere dynamics in wild banded mongooses: Evaluating longitudinal and quasi-longitudinal markers of senescence. Exp Gerontol
Telomere dynamics in wild banded mongooses: Evaluating longitudinal and quasi-longitudinal markers of senescence.
Telomere length and the rate of telomere shortening have been suggested as particularly useful physiological biomarkers of the processes involved in senescent decline of somatic and reproductive function. However, longitudinal data on changes in telomere length across the lifespan are difficult to obtain, particularly for long-lived animals. Quasi-longitudinal studies have been proposed as a method to gain insight into telomere dynamics in long-lived species. In this method, minimally replicative cells are used as the baseline telomere length against which telomere length in highly replicative cells (which represent the current state) can be compared. Here we test the assumptions and predictions of the quasi-longitudinal approach using longitudinal telomere data in a wild cooperative mammal, the banded mongoose, Mungos mungo. Contrary to our prediction, telomere length (TL) was longer in leukocytes than in ear cartilage. Longitudinally, the TL of ear cartilage shortened with age, but there was no change in the TL of leukocytes, and we also observed many individuals in which TL increased rather than decreased with age. Leukocyte TL but not cartilage TL was a predictor of total lifespan, while neither predicted post-sampling survival. Our data do not support the hypothesis that cross-tissue comparison in TL can act as a quasi-longitudinal marker of senescence. Rather, our results suggest that telomere dynamics in banded mongooses are more complex than is typically assumed, and that longitudinal studies across whole life spans are required to elucidate the link between telomere dynamics and senescence in natural populations. Abstract
. Author URL
Johnstone RA, Croft DP, Thompson FJ, Cant MA (2018). The ecology and evolution of intergroup conflict: a preliminary model.
Vitikainen EIK, Marshall HH, Thompson FJ, Sanderson JL, Bell MBV, Gilchrist JS, Hodge SJ, Nichols HJ, Cant MA
(2017). Biased escorts: Offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder. Proceedings of the Royal Society B: Biological Sciences
Biased escorts: Offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder
Kin selection theory predicts that animals should direct costly care where inclusive fitness gains are highest. Individuals may achieve this by directing care at closer relatives, yet evidence for such discrimination in vertebrates is equivocal. We investigated patterns of cooperative care in banded mongooses, where communal litters are raised by adult ‘escorts’ who form exclusive caring relationships with individual pups. We found no evidence that escorts and pups assort by parentage or relatedness. However, the time males spent escorting increased with increasing relatedness to the other group members, and to the pup they had paired with. Thus, we found no effect of relatedness in partner choice, but (in males) increasing helping effort with relatedness once partner choices had been made. Unexpectedly, the results showed clear assortment by sex, with female carers being more likely to tend to female pups, and male carers to male pups. This sex-specific assortment in helping behaviour has potential lifelong impacts on individual development and may impact the future size and composition of natal groups and dispersing cohorts. Where relatedness between helpers and recipients is already high, individuals may be better off choosing partners using other predictors of the costs and benefits of cooperation, without the need for possibly costly within-group kin discrimination. Abstract
Thompson FJ, Marshall HH, Vitikainen EIK, Cant MA
(2017). Causes and consequences of intergroup conflict in cooperative banded mongooses. Animal Behaviour
Causes and consequences of intergroup conflict in cooperative banded mongooses
Conflict between groups is a notable feature of many animal societies. Recent theoretical models suggest that violent intergroup conflict can shape patterns of within-group cooperation. However, despite its prevalence in social species, the adaptive significance of violent intergroup conflict has been little explored outside of humans and chimpanzees, Pan troglodytes. A barrier to current understanding of the role of intergroup conflict in the evolution of social behaviour is a lack of information on the causes and consequences of aggression between groups. Here, we examined the causes and fitness consequences of intergroup conflict in the banded mongoose, Mungos mungo, using a 16-year data set of observed intergroup interactions, life history and behaviour. Banded mongooses are cooperative breeders that live in highly territorial groups and engage in frequent, aggressive and violent intergroup interactions. We found that intensified population-wide competition for food and mates increased the probability of intergroup interactions, and that increased intergroup conflict was associated with periods in which groups were growing in size. Intergroup conflict had fitness costs in terms of reduced litter and adult survival but no cost to pregnant females: in fact, females were less likely to abort following an intergroup interaction than when there had been no recent intergroup conflict. Our results suggest that intergroup conflict has measurable costs to both individuals and groups in the long and short term, and that levels of conflict among groups could be high enough to affect patterns of within-group cooperative behaviour. Establishing the consequences of intergroup conflict in cooperative species can shed light on patterns of conflict and cooperation within groups and, in turn, facilitate our understanding of social evolution. Abstract
Marshall HH, Vitikainen EIK, Mwanguhya F, Businge R, Kyabulima S, Hares MC, Inzani E, Kalema-Zikusoka G, Mwesige K, Nichols HJ, et al
(2017). Data supporting Marshall et al. (2017) in Ecology and Evolution.
Data supporting Marshall et al. (2017) in Ecology and Evolution
This data supports the following publication: Abstract
Marshall HH, Vitikainen EIK, Mwanguhya F, Businge R, Kyabulima S, Hares MC, Inzani E, Kalema-Zikusosa G, Mwesige K, Nichols HJ, et al (2017). Lifetime fitness consequences of early-life ecological hardship in a wild mammal population. Ecology and Evolution
Thompson F, Marshall H, Vitikainen E, Cant M
(2017). Data supporting Thompson et al. (2017) Animal Behaviour.
Data supporting Thompson et al. (2017) Animal Behaviour
This data supports the following publication:Faye J. Thompson, Harry H. Marshall, Emma I.K. Vitikainen & Michael A. Cant (2017) Causes and consequences of intergroup conflict in cooperative banded mongooses. Animal BehaviourPlease read the "Read Me.txt" file for a full description of the data contained in each data set Abstract
Thompson F, Cant M, Marshall H, Vitikainen E, Sanderson J, Nichols H, Gilchrist J, Bell M, Young A, Hodge S, et al
(2017). Data supporting Thompson et al. 2017 Explaining negative kin discrimination in a cooperative mammal society. PNAS.
Data supporting Thompson et al. 2017 Explaining negative kin discrimination in a cooperative mammal society. PNAS.
This data supports the following publication:Faye J. Thompson, Michael A. Cant, Harry H. Marshall, Emma I.K. Vitikainen, Jennifer L. Sanderson, Hazel J. Nichols, Jason S. Gilchrist, Matthew B.V. Bell, Andrew J. Young, Sarah J. Hodge & Rufus A. Johnstone (2017) Explaining negative kin discrimination in a cooperative mammal society. Proceedings of the National Academy of SciencesPlease read the "Read Me.txt" file for a full description of the data contained in each data set Abstract
Thompson F, Marshall H, Vitikainen E, young A, cant M
(2017). Data supporting Thompson et al. 2017 Individual and demographic consequences of mass eviction in cooperative banded mongooses. Animal Behaviour.
Data supporting Thompson et al. 2017 Individual and demographic consequences of mass eviction in cooperative banded mongooses. Animal Behaviour.
This data supports the following publication:Faye J. Thompson, Harry H. Marshall, Emma I.K. Vitikainen, Andrew J. Young & Michael A. Cant (2017) Individual and demographic consequences of mass eviction in cooperative banded mongooses. Animal BehaviourPlease read the "Read Me.txt" file for a full description of the data contained in each data set Abstract
Thompson FJ, Cant MA, Marshall HH, Vitikainen EIK, Sanderson JL, Nichols HJ, Gilchrist JS, Bell MBV, Young AJ, Hodge SJ, et al
(2017). Explaining negative kin discrimination in a cooperative mammal society. Proceedings of the National Academy of Sciences of the United States of America
Explaining negative kin discrimination in a cooperative mammal society
Kin selection theory predicts that, where kin discrimination is possible, animals should typically act more favorably toward closer genetic relatives and direct aggression toward less closely related individuals. Contrary to this prediction, we present data from an 18-y study of wild banded mongooses, Mungos mungo, showing that females that are more closely related to dominant individuals are specifically targeted for forcible eviction from the group, often suffering severe injury, and sometimes death, as a result. This pattern cannot be explained by inbreeding avoidance or as a response to more intense local competition among kin. Instead, we use game theory to show that such negative kin discrimination can be explained by selection for unrelated targets to invest more effort in resisting eviction. Consistent with our model, negative kin discrimination is restricted to eviction attempts of older females capable of resistance; dominants exhibit no kin discrimination when attempting to evict younger females, nor do they discriminate between more closely or less closely related young when carrying out infanticidal attacks on vulnerable infants who cannot defend themselves. We suggest that in contexts where recipients of selfish acts are capable of resistance, the usual prediction of positive kin discrimination can be reversed. Kin selection theory, as an explanation for social behavior, can benefit from much greater exploration of sequential social interactions. Abstract
Thompson FJ, Marshall HH, Vitikainen EIK, Young AJ, Cant MA
(2017). Individual and demographic consequences of mass eviction in cooperative banded mongooses. Animal Behaviour
Individual and demographic consequences of mass eviction in cooperative banded mongooses
In animal societies, conflict within groups can result in eviction, where individuals are often permanently expelled from their group. To understand the evolution of eviction and its role in the resolution of within-group conflict requires information on the demographic consequences of eviction for individuals and groups. However, such information is usually difficult to obtain because of the difficulty in tracking and monitoring individuals after they are evicted from their natal groups. Here we used a 15-year data set on life history and demography to investigate the consequences of eviction in a tractable cooperatively breeding mammal, the banded mongoose, Mungos mungo. In this species, groups of individuals are periodically evicted en masse and eviction is a primary mechanism by which new groups form in the study population. Following eviction, we found sex differences in dispersal distance: some females established new groups on the study peninsula but males always dispersed away from the study peninsula. Evicted females suffered reduced reproductive success in the year after eviction. For the evicting group, eviction was associated with increased per capita reproductive success for females, suggesting that eviction is successful in reducing reproductive competition. However, eviction was also associated with increased intergroup conflict for the evicting group. Our results suggest that within-group conflict resolution strategies affect group productivity, group interactions and the structure of the population, and hence have fitness impacts that reach beyond the individual evictors and evictees involved in eviction. Abstract
Marshall HH, Vitikainen EIK, Mwanguhya F, Businge R, Kyabulima S, Hares MC, Inzani E, Kalema-Zikusoka G, Mwesige K, Nichols HJ, et al
(2017). Lifetime fitness consequences of early-life ecological hardship in a wild mammal population. Ecology and Evolution
Lifetime fitness consequences of early-life ecological hardship in a wild mammal population
Early-life ecological conditions have major effects on survival and reproduction. Numerous studies in wild systems show fitness benefits of good quality early-life ecological conditions (“silver-spoon” effects). Recently, however, some studies have reported that poor-quality early-life ecological conditions are associated with later-life fitness advantages and that the effect of early-life conditions can be sex-specific. Furthermore, few studies have investigated the effect of the variability of early-life ecological conditions on later-life fitness. Here, we test how the mean and variability of early-life ecological conditions affect the longevity and reproduction of males and females using 14 years of data on wild banded mongooses (Mungos mungo). Males that experienced highly variable ecological conditions during development lived longer and had greater lifetime fitness, while those that experienced poor early-life conditions lived longer but at a cost of reduced fertility. In females, there were no such effects. Our study suggests that exposure to more variable environments in early life can result in lifetime fitness benefits, whereas differences in the mean early-life conditions experienced mediate a life-history trade-off between survival and reproduction. It also demonstrates how early-life ecological conditions can produce different selection pressures on males and females. Abstract
Cant MA, Nichols HJ, Thompson FJ, Vitikainen EIK (2016). Banded mongooses: demography, life history, and social behavior. In Koenig WD, Dickinson JL (Eds.) Cooperative breeding in vertebrates: studies of ecology, evolution and behavior, Cambridge: Cambridge University Press, 318-337.
Vitikainen EIK, Cant MA, Sanderson JL, Mitchell C, Nichols HJ, Marshall HH, Thompson FJ, Gilchrist JS, Hodge SJ, Johnstone RA, et al
(2016). Evidence of Oxidative Shielding of Offspring in a Wild Mammal. FRONTIERS IN ECOLOGY AND EVOLUTION
, 4 Author URL
Vitikainen EIK, Cant MA, Sanderson JL, Mitchell C, Nichols HJ, Marshall HH, Thompson FJ, Gilchrist JS, Hodge SJ, Johnstone RA, et al (2016). Evidence of Oxidative Shielding of Offspring in a Wild Mammal. Frontiers in Ecology and Evolution, 4
Inzani EL, Marshall HH, Sanderson JL, Nichols HJ, Thompson FJ, Kalema-Zikusoka G, Hodge SJ, Cant MA, Vitikainen EIK
(2016). Female reproductive competition explains variation in prenatal investment in wild banded mongooses. Scientific Reports
Female reproductive competition explains variation in prenatal investment in wild banded mongooses
© 2016, Nature Publishing Group. All rights reserved.Female intrasexual competition is intense in cooperatively breeding species where offspring compete locally for resources and helpers. In mammals, females have been proposed to adjust prenatal investment according to the intensity of competition in the postnatal environment (a form of 'predictive adaptive response'; PAR). We carried out a test of this hypothesis using ultrasound scanning of wild female banded mongooses in Uganda. In this species multiple females give birth together to a communal litter, and all females breed regularly from one year old. Total prenatal investment (size times the number of fetuses) increased with the number of potential female breeders in the group. This relationship was driven by fetus size rather than number. The response to competition was particularly strong in low weight females and when ecological conditions were poor. Increased prenatal investment did not trade off against maternal survival. In fact we found the opposite relationship: females with greater levels of prenatal investment had elevated postnatal maternal survival. Our results support the hypothesis that mammalian prenatal development is responsive to the intensity of postnatal competition. Understanding whether these responses are adaptive requires information on the long-term consequences of prenatal investment for offspring fitness. Abstract
Thompson FJ, Marshall HH, Sanderson JL, Vitikainen EIK, Nichols HJ, Gilchrist JS, Young AJ, Hodge SJ, Cant MA
(2016). Reproductive competition triggers mass eviction in cooperative banded mongooses. Proceedings of the Royal Society B: Biological Sciences
Reproductive competition triggers mass eviction in cooperative banded mongooses
. In many vertebrate societies, forced eviction of group members is an important determinant of population structure, but little is known about what triggers eviction. Three main explanations are: (i) the reproductive competition hypothesis, (ii) the coercion of cooperation hypothesis, and (iii) the adaptive forced dispersal hypothesis. The last hypothesis proposes that dominant individuals use eviction as an adaptive strategy to propagate copies of their alleles through a highly structured population. We tested these hypotheses as explanations for eviction in cooperatively breeding banded mongooses (
. Mungos mungo
. ), using a 16-year dataset on life history, behaviour and relatedness. In this species, groups of females, or mixed-sex groups, are periodically evicted
. en masse
. Our evidence suggests that reproductive competition is the main ultimate trigger for eviction for both sexes. We find little evidence that mass eviction is used to coerce helping, or as a mechanism to force dispersal of relatives into the population. Eviction of females changes the landscape of reproductive competition for remaining males, which may explain why males are evicted alongside females. Our results show that the consequences of resolving within-group conflict resonate through groups and populations to affect population structure, with important implications for social evolution.
Marshall HH, Sanderson JL, Mwanguhya F, Businge R, Kyabulima S, Hares MC, Inzani E, Kalema-Zikusoka G, Mwesige K, Thompson FJ, et al
(2016). Variable ecological conditions promote male
helping by changing banded mongoose group
composition. Behavioral Ecology
Variable ecological conditions promote male
helping by changing banded mongoose group
Ecological conditions are expected to have an important influence on individuals’ investment in cooperative care. However, the nature Abstract
of their effects is unclear: both favorable and unfavorable conditions have been found to promote helping behavior. Recent studies
provide a possible explanation for these conflicting results by suggesting that increased ecological variability, rather than changes in
mean conditions, promote cooperative care. However, no study has tested whether increased ecological variability promotes individual-
level helping behavior or the mechanisms involved. We test this hypothesis in a long-term study population of the cooperatively
breeding banded mongoose, Mungos mungo, using 14 years of behavioral and meteorological data to explore how the mean and variability
of ecological conditions influence individual behavior, body condition, and survival. Female body condition was more sensitive
to changes in rainfall leading to poorer female survival and pronounced male-biased group compositions after periods of high rainfall
variability. After such periods, older males invested more in helping behavior, potentially because they had fewer mating opportunities.
These results provide the first empirical evidence for increased individual helping effort in more variable ecological conditions
and suggest this arises because of individual differences in the effect of ecological conditions on body condition and survival, and the
knock-on effect on social group composition. Individual differences in sensitivity to environmental variability, and the impacts this has
on the internal structure and composition of animal groups, can exert a strong influence on the evolution and maintenance of social
behaviors, such as cooperative care.
Sanderson JL, Nichols HJ, Marshall HH, Vitikainen EIK, Thompson FJ, Walker SL, Cant MA, Young AJ
(2015). Elevated glucocorticoid concentrations during gestation predict reduced reproductive success in subordinate female banded mongooses. Biology Letters
Elevated glucocorticoid concentrations during gestation predict reduced reproductive success in subordinate female banded mongooses
Dominant females in social species have been hypothesized to reduce the reproductive success of their subordinates by inducing elevated circulating glucocorticoid (GC) concentrations. However, this 'stress-related suppression' hypothesis has received little support in cooperatively breeding species, despite evident reproductive skews among females.We tested this hypothesis in the banded mongoose (Mungos mungo), a cooperative mammal in which multiple females conceive and carry to term in each communal breeding attempt. As predicted, lower ranked females had lower reproductive success, even among females that carried to term. While there were no rank-related differences in faecal glucocorticoid (fGC) concentrations prior to gestation or in the first trimester, lower ranked females had significantly higher fGC concentrations than higher ranked females in the second and third trimesters. Finally, females with higher fGC concentrations during the third trimester lost a greater proportion of their gestated young prior to their emergence from the burrow. Together, our results are consistent with a role for rankrelated maternal stress in generating reproductive skew among females in this cooperative breeder. While studies of reproductive skew frequently consider the possibility that rank-related stress reduces the conception rates of subordinates, our findings highlight the possibility of detrimental effects on reproductive outcomes even after pregnancies have become established. Abstract
Donaldson L, Thompson FJ, Field J, Cant MA
(2014). Do paper wasps negotiate over helping effort?. Behavioral Ecology
Do paper wasps negotiate over helping effort?
Recent theory and empirical studies of avian biparental systems suggest that animals resolve conflict over parental care via a process of behavioral negotiation or "rules for responding." Less is known, however, about whether negotiation over helping effort occurs in cooperatively breeding animal societies or whether behavioral negotiation requires a relatively large brain. In this study, we tested whether negotiation over help occurs in a social insect, the paper wasp Polistes dominulus, by recording individual responses to both observed and experimentally induced foraging returns by other group members. In our experiments, we manipulated food delivery to the nest in 2 ways: 1) by catching departing foragers and giving them larval food to take back to the nest and 2) by giving larval food directly to wasps on the nest, which they then fed to larvae, so increasing food delivery independently of helper effort. We found no evidence from Experiment 1 that helpers adjusted their own foraging effort according to the foraging effort of other group members. However, when food was provided directly to the nest, wasps did respond by reducing their own foraging effort. One interpretation of this result is that paper wasp helpers adjust their helping effort according to the level of offspring need rather than the work rate of other helpers. Negotiation based on indicators of demand rather than work rate is a likely mechanism to resolve conflict over investment in teams where helpers cannot observe each other's work rate directly, as is commonly the case in insect and vertebrate societies. © the Author 2013. Abstract
Thompson FJ, Donaldson L, Johnstone RA, Field J, Cant MA
(2014). Dominant aggression as a deterrent signal in paper wasps. Behavioral Ecology
Dominant aggression as a deterrent signal in paper wasps
Low-level social aggression is a conspicuous feature of cooperative animal societies, but its precise function is usually unclear. One long-standing hypothesis is that aggressive displays by dominant individuals serve to reduce uncertainty about relative strength and deter subordinates from starting fights that they are unlikely to win. However, most formal theoretical models of this idea do not consider how the credibility of deterrent signals might change over time in social groups. We developed a simple model of dominant aggression as a deterrent signal, which takes into account how credibility changes over time and how selection should act on receiver memory. We then carried out an experimental test of the predictions of our model on a field population of the paper wasp, Polistes dominulus. The match between our theoretical and empirical results suggests that low-level social aggression can help to maintain the stability and productivity of cooperative associations in this species. Moreover, our work suggests that rates of aggression in animal societies and the robustness of social memories are likely to be intimately related. © 2014 the Author. Abstract