Physiological mechanisms mediating patterns of reproductive suppression and alloparental care in cooperatively breeding carnivores

2018 ◽  
Vol 193 ◽  
pp. 167-178 ◽  
Author(s):  
Tracy M. Montgomery ◽  
Erika L. Pendleton ◽  
Jennifer E. Smith
Keyword(s):  
Alloparental Care ◽  
Reproductive Suppression ◽  
Physiological Mechanisms ◽  
Cooperatively Breeding

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

scholarly journals Pregnancy is detected via odour in a wild cooperative breeder

2017 ◽  
Vol 13 (11) ◽  
pp. 20170441 ◽  
Author(s):  
J. Mitchell ◽  
M. A. Cant ◽  
H. J. Nichols
Keyword(s):  
Scent Marking ◽  
Alloparental Care ◽  
Scent Mark ◽  
Reproductive State ◽  
Reproductive Suppression ◽  
Pregnant Females ◽  
Direct Demonstration ◽  
Cooperatively Breeding ◽  
Banded Mongoose ◽  
Mungos Mungo

Among mammals, scent has long been known to encode oestrus; however, in many species, detecting pregnancy may also be important in terms of both competition and mate-choice. Here, we show, through odour presentation experiments, that pregnancy is discernible via scent by both sexes in the cooperatively breeding banded mongoose, Mungos mungo . Males spent more time investigating and were more likely to scent mark the odours of non-pregnant females, compared to pregnant females. Females showed increased levels of scent marking when odours were of the same reproductive state as themselves. These results present the first direct demonstration that pregnancy is detectable via scent in wild cooperative breeders. Detecting pregnancy may be particularly important in cooperative breeders as, in addition to the competition between males for receptive mates, there is also intense competition between females for access to alloparental care. Consequently, dominant females benefit from targeting reproductive suppression towards subordinates that represent direct threats, such as pregnant females.

Filling in the holes: The reproductive biology of the understudied Mahali mole-rat (Cryptomys hottentotus mahali)

2021 ◽  
Vol 99 (9) ◽  
pp. 801-811 ◽  
Author(s):  
D.W. Hart ◽  
K. Medger ◽  
B. van Jaarsveld ◽  
N.C. Bennett
Keyword(s):  
Reproductive Tract ◽  
Breeding Strategy ◽  
Arid Environments ◽  
Reproductive Suppression ◽  
Mole Rat ◽  
Evolution Of Sociality ◽  
Great Insight ◽  
Cooperatively Breeding ◽  
Males And Females ◽  
Insight Into

African mole-rats have provided great insight into mammalian evolution of sociality and reproductive strategy. However, some species have not received attention, and these may provide further insights into these evolutionary questions. The cooperatively breeding Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is one such species. Body mass, reproductive-tract morphometrics, gonad histology, and plasma reproductive hormone concentrations were studied for breeding and non-breeding males and females over 1 year. This study aimed to discern if this species exhibits a seasonal or aseasonal breeding pattern and whether there is a relaxation of reproductive suppression at any point in the year in non-breeding animals. The pattern of reproductive relaxation during the wetter months is similar to other African mole-rat species. Interestingly, births and pregnant breeding females were recorded throughout the year, thus indicating an aseasonal breeding strategy, despite inhabiting a region that experiences seasonal rainfall. However, there were periods of the year favouring increased reproduction to enable an increased likelihood of offspring survival. This suggests that the Mahali mole-rat may be an opportunistic breeder possibly brought about by the benefits of living in a cooperatively breeding group and potentially moving into more arid environments that were previously unexploited by the genus Cryptomys Gray, 1864.

Experimental predator intrusions in a cooperative breeder reveal threat-dependent task partitioning

2020 ◽  
Vol 31 (6) ◽  
pp. 1369-1378 ◽  
Author(s):  
Dario Josi ◽  
Annika Freudiger ◽  
Michael Taborsky ◽  
Joachim G Frommen
Keyword(s):  
Behavioral Responses ◽  
Alloparental Care ◽  
Potential Threat ◽  
Antipredator Defense ◽  
Outside Options ◽  
Cooperatively Breeding ◽  
Indirect Fitness ◽  
Antipredator Behaviors ◽  
Group Members ◽  
Eusocial Animals

Abstract In cooperatively breeding species, nonbreeding individuals provide alloparental care and help in territory maintenance and defense. Antipredator behaviors of subordinates can enhance offspring survival, which may provide direct and indirect fitness benefits to all group members. Helping abilities and involved costs and benefits, risks, and outside options (e.g., breeding independently) usually diverge between group members, which calls for status-specific differentiated behavioral responses. Such role differentiation within groups may generate task-specific division of labor, as exemplified by eusocial animals. In vertebrates, little is known about such task differentiation among group members. We show how breeders and helpers of the cooperatively breeding cichlid Neolamprologus savoryi partition predator defense depending on intruder type and the presence of dependent young. In the field, we experimentally simulated intrusions by different fish species posing a risk either specifically to eggs, young, or adults. We used intrusions by harmless algae eaters as a control. Breeders defended most when dependent young were present, while helper investment hinged mainly on their body size and on the potential threat posed by the respective intruders. Breeders and helpers partitioned defense tasks primarily when dependent young were exposed to immediate risk, with breeders investing most in antipredator defense, while helpers increased guarding and care in the breeding chamber. Breeders’ defense likely benefits helpers as well, as it was especially enhanced in the treatment where helpers were also at risk. These findings illustrate that in a highly social fish different group members exhibit fine-tuned behavioral responses in dependence of ecological and reproductive parameter variation.

scholarly journals Commodity-specific punishment for experimentally induced defection in cooperatively breeding fish

2020 ◽  
Vol 7 (2) ◽  
pp. 191808 ◽  
Author(s):  
Jan Naef ◽  
Michael Taborsky
Keyword(s):  
Social Dynamics ◽  
Negotiation Process ◽  
Regulatory Mechanisms ◽  
Alloparental Care ◽  
Cooperative Groups ◽  
Compensatory Response ◽  
Helping Behaviours ◽  
Cooperatively Breeding ◽  
Full Factorial ◽  
Behavioural Function

Coercion is an important but underrated component in the evolution of cooperative behaviour. According to the pay-to-stay hypothesis of cooperative breeding, subordinates trade alloparental care for the concession to stay in the group. Punishment of idle subordinates is a key prediction of this hypothesis, which has received some experimental scrutiny. However, previous studies neither allowed separating between punishment and effects of disruption of social dynamics, nor did they differentiate between different helping behaviours that may reflect either mutualistic or reciprocal interaction dynamics. In the cooperative breeder Neolamprologus pulcher , we experimentally engineered the ability of subordinates to contribute to alloparental care by manipulating two different helping behaviours independently from one another in a full factorial design. We recorded the treatment effects on breeder aggression, subordinate helping efforts and submissive displays. We found two divergent regulatory mechanisms of cooperation, dependent on behavioural function. Experimental impediment of territory maintenance of subordinates triggered punishment by dominants, whereas prevented defence against egg predators released a compensatory response of subordinates without any enforcement, suggesting pre-emptive appeasement. These effects occurred independently of one another. Apparently, in the complex negotiation process among members of cooperative groups, behaviours fulfilling different functions may be regulated by divergent interaction mechanisms.

scholarly journals Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130565 ◽  
Author(s):  
Ben J. Hatchwell ◽  
Philippa R. Gullett ◽  
Mark J. Adams
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Empirical Studies ◽  
Alloparental Care ◽  
Hamilton’S Rule ◽  
Long Term Study ◽  
Inclusive Fitness Theory ◽  
Cooperatively Breeding ◽  
Helping Behaviour ◽  
Hamilton's Rule

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist ( c ) are outweighed by the benefit to the recipient ( b ), weighted by the relatedness of altruist to recipient ( r ), i.e. Hamilton's rule rb > c . Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.

Band Structure and Failures of Reproductive Suppression in a Cooperatively Breeding Carnivore, the Slender-Tailed Meerkat (Suricata Suricatta)

Behaviour ◽  
1997 ◽  
Vol 134 (11-12) ◽  
pp. 827-848 ◽  
Author(s):  
David W. Macdonald ◽  
Sean P. Doolan
Keyword(s):  
Band Structure ◽  
Adult Males ◽  
High Turnover ◽  
Reproductive Suppression ◽  
Suricata Suricatta ◽  
Adult Females ◽  
Reproductive Female ◽  
Band Size ◽  
Cooperatively Breeding ◽  
Reproductive Females

AbstractThe extent to which band structure influences the distribution of breeding activity is unknown for the slender-tailed meerkat Suricata suricatta, a cooperatively breeding mongoose. Here we present the residence histories of three focal bands monitored over ten band-years in the southwestern Kalahari, with less detailed data derived from non-focal bands for a further 20 band-years. Mean total band size early in the breeding season was 10, and mean size excluding juveniles was 6.7. Despite a tendency towards females among juveniles, and males among yearlings and adults, sex ratios within each age class did not significantly deviate from unity, but at the population level there were significantly more adult males than reproductive females. A large proportion (71.6%) of adult females bred, and failures of reproductive suppression occurred in 40% of band years. This incidence was high in all years and was not obviously related to environmental conditions. Bands with more than one reproductive female contained significantly more adults and adult females than bands with only a single reproductive female. There was a strong correlation between numbers of reproductive females and numbers of adult females in a band. Most (68%) subordinate females which bred were aged three years or more. Reproductive competition was strong and there was a negative correlation between numbers of adult females, breeding females or adult males and per capita juvenile production. Meerkat bands are unusual among cooperative breeders because many individuals were non-kin and the relative constancy in band size within and between years masked a high turnover of membership: all animals of known origin aged three years or older, were immigrants, although philopatry was commoner among younger animals. Our data show that meerkats employ a range of reproductive strategies: bands exhibiting a spectrum of reproductive suppression coexist, and individuals respond to the opportunities afforded by their social environments.

No Evidence for Enforced Alloparental Care in a Cooperatively Breeding Parrot

Ethology ◽  
2016 ◽  
Vol 122 (5) ◽  
pp. 389-398 ◽  
Author(s):  
Jos Kramer ◽  
Nadine Klauke ◽  
Michael Bauer ◽  
H. Martin Schaefer
Keyword(s):  
Alloparental Care ◽  
Cooperatively Breeding

scholarly journals Stress hormones and sociality: integrating social and environmental stressors

2007 ◽  
Vol 274 (1612) ◽  
pp. 967-975 ◽  
Author(s):  
Dustin R Rubenstein
Keyword(s):  
Environmental Factors ◽  
Social Interactions ◽  
Social Factors ◽  
Stress Hormones ◽  
Environmental Stressors ◽  
Reproductive Decisions ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Maximal Stress ◽  
Plural Breeding

In cooperatively breeding species, reproductive decisions and breeding roles may be influenced by environmental (food resources) or social factors (reproductive suppression of subordinates by dominants). Studies of glucocorticoid stress hormones in cooperatively breeding species suggest that breeding roles and hormone levels are related to the relative costs of dominance and subordination, which are driven primarily by social interactions. Few studies, however, have considered how environmental factors affect glucocorticoid levels and breeding roles in cooperative breeders, even though environmental stressors modulate seasonal glucocorticoid release and often influence breeding roles. I examined baseline and stress-induced levels of the glucocorticoid corticosterone (CORT) across 4 years in the plural breeding superb starling, Lamprotornis superbus , to determine whether (i) environmental factors (namely rainfall) directly influence breeding roles or (ii) environmental factors influence social interactions, which in turn drive breeding roles. Chronic baseline and maximal stress-induced CORT changed significantly across years as a function of pre-breeding rainfall, but dominant and subordinate individuals responded differently. Pre-breeding rainfall was also correlated directly with breeding roles. The results are most consistent with the hypothesis that environmental conditions influenced the relative costs of dominance and subordination, which in turn affected the degree and intensity of social interactions and ultimately reproductive decisions and breeding roles.

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