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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) weight gain by dominant females during pregnancy (analysis conducted on 12 females over 54 pregnancies (23 treated and 31 control)).; and (b) pup weight at emergence (analysis conducted on 215 pups (128 treated, 87 control) from 51 litters (22 treated and 29 control) born to 12 dominant females. Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to weigh animals within target time windows.
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f2: The effect of experimental suppression of subordinate female reproduction on:(a) weight gain by dominant females during pregnancy (analysis conducted on 12 females over 54 pregnancies (23 treated and 31 control)).; and (b) pup weight at emergence (analysis conducted on 215 pups (128 treated, 87 control) from 51 litters (22 treated and 29 control) born to 12 dominant females. Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to weigh animals within target time windows.

Mentions: To test whether dominants benefited from reduced aggression toward subordinates, we analysed dominant foraging efficiency, since foraging may have been less interrupted. Our focal watches recorded time spent foraging and prey biomass captured, and revealed that dominant females in treated groups captured more food per minute (interaction between dominance and treatment, F1,3764=4.63, P=0.032; Supplementary Table 7). This increase in foraging efficiency, coupled with the reduced effort invested in evicting subordinates, meant that dominant females in treated groups gained more weight during pregnancy (LMM F1,53=5.62, P=0.022; Fig. 2a; Supplementary Table 8), and pups born to dominant females in Treated groups were heavier when they first emerged from their burrows (LMM F1,214=6.46, P=0.021; Fig. 2b; Supplementary Table 9; n=128 Treated, 87 control pups). The strength of the effect is emphasized by the fact that pup weight was also affected by the number of subordinate females allolactating (F1,214=24.59, P<0.001), and there were fewer allolactating females in treated groups (LMM F1,58=7.59, P=0.008; Supplementary Table 10). The positive effect of additional allolactators implies that successful reproduction by subordinates carries additional costs to dominants, since surviving subordinate pups would detract from the milk available to dominant pups.


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) weight gain by dominant females during pregnancy (analysis conducted on 12 females over 54 pregnancies (23 treated and 31 control)).; and (b) pup weight at emergence (analysis conducted on 215 pups (128 treated, 87 control) from 51 litters (22 treated and 29 control) born to 12 dominant females. Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to weigh animals within target time windows.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: The effect of experimental suppression of subordinate female reproduction on:(a) weight gain by dominant females during pregnancy (analysis conducted on 12 females over 54 pregnancies (23 treated and 31 control)).; and (b) pup weight at emergence (analysis conducted on 215 pups (128 treated, 87 control) from 51 litters (22 treated and 29 control) born to 12 dominant females. Means ±s.e. Sample sizes may be less than complete experimental sample because it was not always possible to weigh animals within target time windows.
Mentions: To test whether dominants benefited from reduced aggression toward subordinates, we analysed dominant foraging efficiency, since foraging may have been less interrupted. Our focal watches recorded time spent foraging and prey biomass captured, and revealed that dominant females in treated groups captured more food per minute (interaction between dominance and treatment, F1,3764=4.63, P=0.032; Supplementary Table 7). This increase in foraging efficiency, coupled with the reduced effort invested in evicting subordinates, meant that dominant females in treated groups gained more weight during pregnancy (LMM F1,53=5.62, P=0.022; Fig. 2a; Supplementary Table 8), and pups born to dominant females in Treated groups were heavier when they first emerged from their burrows (LMM F1,214=6.46, P=0.021; Fig. 2b; Supplementary Table 9; n=128 Treated, 87 control pups). The strength of the effect is emphasized by the fact that pup weight was also affected by the number of subordinate females allolactating (F1,214=24.59, P<0.001), and there were fewer allolactating females in treated groups (LMM F1,58=7.59, P=0.008; Supplementary Table 10). The positive effect of additional allolactators implies that successful reproduction by subordinates carries additional costs to dominants, since surviving subordinate pups would detract from the milk available to dominant pups.

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