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Suppressing subordinate reproduction provides benefits to dominants in cooperative societies of meerkats.

Bell MB, Cant MA, Borgeaud C, Thavarajah N, Samson J, Clutton-Brock TH - Nat Commun (2014)

Bottom Line: Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed.When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster.These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Zoology, Large Animal Research Group, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK [2].

ABSTRACT
In many animal societies, a small proportion of dominant females monopolize reproduction by actively suppressing subordinates. Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed. Here, we describe the consequences of experimentally preventing subordinate breeding in 12 groups of wild meerkats (Suricata suricatta) for three breeding attempts, using contraceptive injections. When subordinates are prevented from breeding, dominants are less aggressive towards subordinates and evict them less often, leading to a higher ratio of helpers to dependent pups, and increased provisioning of the dominant's pups by subordinate females. When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster. These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.

No MeSH data available.


Related in: MedlinePlus

The effect of experimental suppression of subordinate female reproduction on:(a) the rate at which dominant females attack subordinates (analysis conducted on 1,952 focal watches of 12 dominant females); (b) the probability that a subordinate female was evicted during a breeding attempt (analysis conducted on 128 subordinate females, present at 59 breeding attempts (33 control and 26 treated) by 12 dominant females; (c) the ratio of adult females to dependent pups during the period of peak pup provisioning (20 to 40 days after birth; analysis conducted on 59 breeding attempts (33 control and 26 treated) born to 12 dominant females); and (d) provisioning rates by subordinate females (mass of food per minute, square root transformed; analysis was conducted on 1,050 focal watches, of 72 subordinate females). Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to observe specific animals within target time windows.
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f1: The effect of experimental suppression of subordinate female reproduction on:(a) the rate at which dominant females attack subordinates (analysis conducted on 1,952 focal watches of 12 dominant females); (b) the probability that a subordinate female was evicted during a breeding attempt (analysis conducted on 128 subordinate females, present at 59 breeding attempts (33 control and 26 treated) by 12 dominant females; (c) the ratio of adult females to dependent pups during the period of peak pup provisioning (20 to 40 days after birth; analysis conducted on 59 breeding attempts (33 control and 26 treated) born to 12 dominant females); and (d) provisioning rates by subordinate females (mass of food per minute, square root transformed; analysis was conducted on 1,050 focal watches, of 72 subordinate females). Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to observe specific animals within target time windows.

Mentions: Throughout the experiment, we visited the groups at least twice per week, to collect behavioural data, record group composition and life history events, and weigh animals (who have been trained to step onto portable electronic lab scales). Every week, we conducted at least two 30-min focal watches on each dominant female (to give a total of 1,067 h of observations on 12 females), recording every instance of aggression directed towards subordinate females. Dominant females attacked treated subordinates at lower rates (linear mixed model (LMM), F1,1951=8.74, P=0.003; Fig. 1a.; Supplementary Table 1). We also recorded the total amount of time when at least one subordinate female was within 2 m of the dominant, finding that dominants were more tolerant of the presence of treated subordinates (LMM F1,1951=8.03, P=0.005; Supplementary Table 2). Similar focal observations on the two largest subordinate females currently present in each group (960 h of focal observations on 99 females) recorded the outcome of each foraging attempt. These revealed that treated females were less likely to be interrupted by the dominant female during a foraging bout (generalized linear mixed model (GLMM), F1,1812=11.13, P<0.001; Supplementary Table 3).


Suppressing subordinate reproduction provides benefits to dominants in cooperative societies of meerkats.

Bell MB, Cant MA, Borgeaud C, Thavarajah N, Samson J, Clutton-Brock TH - Nat Commun (2014)

The effect of experimental suppression of subordinate female reproduction on:(a) the rate at which dominant females attack subordinates (analysis conducted on 1,952 focal watches of 12 dominant females); (b) the probability that a subordinate female was evicted during a breeding attempt (analysis conducted on 128 subordinate females, present at 59 breeding attempts (33 control and 26 treated) by 12 dominant females; (c) the ratio of adult females to dependent pups during the period of peak pup provisioning (20 to 40 days after birth; analysis conducted on 59 breeding attempts (33 control and 26 treated) born to 12 dominant females); and (d) provisioning rates by subordinate females (mass of food per minute, square root transformed; analysis was conducted on 1,050 focal watches, of 72 subordinate females). Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to observe specific animals within target time windows.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109011&req=5

f1: The effect of experimental suppression of subordinate female reproduction on:(a) the rate at which dominant females attack subordinates (analysis conducted on 1,952 focal watches of 12 dominant females); (b) the probability that a subordinate female was evicted during a breeding attempt (analysis conducted on 128 subordinate females, present at 59 breeding attempts (33 control and 26 treated) by 12 dominant females; (c) the ratio of adult females to dependent pups during the period of peak pup provisioning (20 to 40 days after birth; analysis conducted on 59 breeding attempts (33 control and 26 treated) born to 12 dominant females); and (d) provisioning rates by subordinate females (mass of food per minute, square root transformed; analysis was conducted on 1,050 focal watches, of 72 subordinate females). Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to observe specific animals within target time windows.
Mentions: Throughout the experiment, we visited the groups at least twice per week, to collect behavioural data, record group composition and life history events, and weigh animals (who have been trained to step onto portable electronic lab scales). Every week, we conducted at least two 30-min focal watches on each dominant female (to give a total of 1,067 h of observations on 12 females), recording every instance of aggression directed towards subordinate females. Dominant females attacked treated subordinates at lower rates (linear mixed model (LMM), F1,1951=8.74, P=0.003; Fig. 1a.; Supplementary Table 1). We also recorded the total amount of time when at least one subordinate female was within 2 m of the dominant, finding that dominants were more tolerant of the presence of treated subordinates (LMM F1,1951=8.03, P=0.005; Supplementary Table 2). Similar focal observations on the two largest subordinate females currently present in each group (960 h of focal observations on 99 females) recorded the outcome of each foraging attempt. These revealed that treated females were less likely to be interrupted by the dominant female during a foraging bout (generalized linear mixed model (GLMM), F1,1812=11.13, P<0.001; Supplementary Table 3).

Bottom Line: Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed.When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster.These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Zoology, Large Animal Research Group, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK [2].

ABSTRACT
In many animal societies, a small proportion of dominant females monopolize reproduction by actively suppressing subordinates. Theory assumes that this is because subordinate reproduction depresses the fitness of dominants, yet the effect of subordinate reproduction on dominant behaviour and reproductive success has never been directly assessed. Here, we describe the consequences of experimentally preventing subordinate breeding in 12 groups of wild meerkats (Suricata suricatta) for three breeding attempts, using contraceptive injections. When subordinates are prevented from breeding, dominants are less aggressive towards subordinates and evict them less often, leading to a higher ratio of helpers to dependent pups, and increased provisioning of the dominant's pups by subordinate females. When subordinate breeding is suppressed, dominants also show improved foraging efficiency, gain more weight during pregnancy and produce heavier pups, which grow faster. These results confirm the benefits of suppression to dominants, and help explain the evolution of singular breeding in vertebrate societies.

No MeSH data available.


Related in: MedlinePlus