Within-group relatedness is correlated with colony-level social structure and reproductive sharing in a social fish.
In group-living species, the degree of relatedness among group members often governs the extent of reproductive sharing, cooperation and conflict within a group. Kinship among group members can be shaped by the presence and location of neighbouring groups, as these provide dispersal or mating opportunities that can dilute kinship among current group members. Here, we assessed how within-group relatedness varies with the density and position of neighbouring social groups in Neolamprologus pulcher, a colonial and group-living cichlid fish. We used restriction site-associated DNA sequencing (RADseq) methods to generate thousands of polymorphic SNPs. Relative to microsatellite data, RADseq data provided much tighter confidence intervals around our relatedness estimates. These data allowed us to document novel patterns of relatedness in relation to colony-level social structure. First, the density of neighbouring groups was negatively correlated with relatedness between subordinates and dominant females within a group, but no such patterns were observed between subordinates and dominant males. Second, subordinates at the colony edge were less related to dominant males in their group than subordinates in the colony centre, suggesting a shorter breeding tenure for dominant males at the colony edge. Finally, subordinates who were closely related to their same-sex dominant were more likely to reproduce, supporting some restraint models of reproductive skew. Collectively, these results demonstrate that within-group relatedness is influenced by the broader social context, and variation between groups in the degree of relatedness between dominants and subordinates can be explained by both patterns of reproductive sharing and the nature of the social landscape.
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Columbus, OH, 43210, USA.
Jennifer K
JK
Hellmann
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Columbus, OH, 43210, USA.
Michael G
MG
Sovic
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Columbus, OH, 43210, USA.
H Lisle
HL
Gibbs
Department of Psychology, Neuroscience, and Behaviour, Aquatic Behavioural Ecology Lab, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
Adam R
AR
Reddon
Department of Psychology, Neuroscience, and Behaviour, Aquatic Behavioural Ecology Lab, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
Constance M
CM
O'Connor
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Columbus, OH, 43210, USA.
Isaac Y
IY
Ligocki
Department of Psychology, Neuroscience, and Behaviour, Aquatic Behavioural Ecology Lab, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
Susan
S
Marsh-Rollo
Department of Psychology, Neuroscience, and Behaviour, Aquatic Behavioural Ecology Lab, McMaster University, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.
Sigal
S
Balshine
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Columbus, OH, 43210, USA.|Department of Mathematics, The Ohio State University, 231 West 18th Avenue, Columbus, OH, 43210, USA.
Ian M
IM
Hamilton
D000818:Animals; D001947:Breeding; D023681:Cichlids / Q000235:genetics* / Q000502:physiology; D005260:Female; D008297:Male; D018895:Microsatellite Repeats; D020641:Polymorphism, Single Nucleotide; D012098:Reproduction; D017422:Sequence Analysis, DNA; D012919:Social Behavior
Neolamprologus pulcher; cooperative breeder; dispersal; neighbour; reproductive skew; restriction site-associated DNA sequencing