Correlates of group size in a cooperatively breeding cichlid fish ( Neolamprologus pulcher )

2001 ◽  
Vol 50 (2) ◽  
pp. 134-140 ◽  
Author(s):  
Sigal Balshine ◽  
Brenda Leach ◽  
Francis Neat ◽  
Hannah Reid ◽  
Michael Taborsky ◽  
...  
Keyword(s):  
Group Size ◽  
Cichlid Fish ◽  
Neolamprologus Pulcher ◽  
Cooperatively Breeding

Large group size yields group stability in the cooperatively breeding cichlid Neolamprologus pulcher

Behaviour ◽  
2005 ◽  
Vol 142 (11-12) ◽  
pp. 1615-1641 ◽  
Author(s):  
Michael Taborsky ◽  
Lyanne Brouwer ◽  
Dik Heg ◽  
Zina Bachar
Keyword(s):  
Group Size ◽  
The Body ◽  
Female Size ◽  
Neolamprologus Pulcher ◽  
Large Group ◽  
Cooperatively Breeding ◽  
Group Members ◽  
One Year ◽  
Large Groups

AbstractGroup size has been shown to positively influence survival of group members in many cooperatively breeding vertebrates, including the Lake Tanganyika cichlid Neolamprologus pulcher, suggesting Allee effects. However, long-term data are scarce to test how these survival differences translate into changes in group extinction risk, group size and composition. We show in a field study of 117 groups from six different colonies (three from two populations each), that group size critically influences these parameters between years. Within one year, 34% of the groups went extinct. Group size correlated positively between years and large groups did not go extinct. The latter were more likely to contain small helpers the subsequent year, which is a cumulative measure of the previous months' reproductive success. Finally, there was a tendency that large groups were more likely to contain a breeding male and female still a year after the first check. The breeder male size, breeder female size, and largest helper size did not influence these parameters, and also did not correlate with the sizes of these categories of fish after one year. This suggests that group size, and not the body size or fighting ability of group members, was the critical variable determining the success of groups. In total, seven groups had fused with other groups between years. To our knowledge, this is the first study showing long-term benefits of large group size in a cooperatively breeding fish. We discuss the importance of differential survival and dispersal of group members for the demonstrated group size effects.

scholarly journals Dominance network structure across reproductive contexts in the cooperatively breeding cichlid fish Neolamprologus pulcher

2015 ◽  
Vol 61 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Cody J. Dey ◽  
Q.Y. Joanne Tan ◽  
Constance M. O’Connor ◽  
Adam R. Reddon ◽  
J. Ryan Caldwell
Keyword(s):  
Social Networks ◽  
Parental Care ◽  
Random Graph ◽  
Behavioral Ecology ◽  
Cichlid Fish ◽  
Life History Stage ◽  
Neolamprologus Pulcher ◽  
Exponential Random Graph ◽  
Dominance Interactions ◽  
Cooperatively Breeding

Abstract While a large number of studies have described animal social networks, we have a poor understanding of how these networks vary with ecological and social conditions. For example, reproductive periods are an important life-history stage that may involve changes in dominance relationships among individuals, yet no study to date has compared social networks of dominance interactions (i.e. dominance networks) across reproductive contexts. We first analyzed a long-term dataset on captive social groups of the cooperatively breeding cichlid Neolamprologus pulcher, and found that eviction events were significantly more common around reproduction than expected by chance. Next, we compared the structure of dominance networks during early parental care and non-reproductive periods, using one of the first applications of exponential random graph models in behavioral biology. Contrary to our predictions, we found that dominance networks showed few changes between early parental care and non-reproductive periods. We found no evidence that dominance interactions became more skewed towards larger individuals, became more frequent between similar-sized individuals, or became more biased towards a particular sex during parental care. However, we did find that there were relatively more dominance interactions between opposite-sex dyads in the early parental care period, which may be a by-product of increased sexual interactions during this time. This is the first study in behavioral ecology to compare social networks using exponential random graph modeling, and demonstrates a powerful analytical framework for future studies in the field.

scholarly journals Strategic reduction of help before dispersal in a cooperative breeder

2013 ◽  
Vol 9 (1) ◽  
pp. 20120878 ◽  
Author(s):  
Markus Zöttl ◽  
Lucille Chapuis ◽  
Manuel Freiburghaus ◽  
Michael Taborsky
Keyword(s):  
Life History ◽  
Natural Population ◽  
Cichlid Fish ◽  
The Other ◽  
Neolamprologus Pulcher ◽  
State Dependent ◽  
Territory Defence ◽  
Cooperatively Breeding ◽  
Sexually Mature

In cooperative breeders, sexually mature subordinates can either queue for chances to inherit the breeding position in their natal group, or disperse to reproduce independently. The choice of one or the other option may be flexible, as when individuals respond to attractive dispersal options, or they may reflect fixed life-history trajectories. Here, we show in a permanently marked, natural population of the cooperatively breeding cichlid fish Neolamprologus pulcher that subordinate helpers reduce investment in territory defence shortly before dispersing. Such reduction of effort is not shown by subordinates who stay and inherit the breeding position. This difference suggests that subordinates ready to leave reduce their investment in the natal territory strategically in favour of future life-history perspectives. It seems to be part of a conditional choice of the dispersal tactic, as this reduction in effort appears only shortly before dispersal, whereas philopatric and dispersing helpers do not differ in defence effort earlier in life. Hence, cooperative territory defence is state-dependent and plastic rather than a consistent part of a fixed life-history trajectory.

Isotocin and sociality in the cooperatively breeding cichlid fish, Neolamprologus pulcher

Behaviour ◽  
2014 ◽  
Vol 151 (10) ◽  
pp. 1389-1411 ◽  
Author(s):  
Adam R. Reddon ◽  
Mathew R. Voisin ◽  
Constance M. O’Connor ◽  
Sigal Balshine
Keyword(s):  
Receptor Antagonist ◽  
Cichlid Fish ◽  
Oxytocin Receptor ◽  
Social Contexts ◽  
Neolamprologus Pulcher ◽  
Proximate Mechanisms ◽  
Wide Range ◽  
Cooperatively Breeding ◽  
Broad Generalization ◽  
Study Species

The ultimate functions of sociality, or the tendency to associate with conspecifics and to live within a social group, are increasingly well understood. However, the proximate mechanisms that mediate this behaviour have received less attention. The oxytocin family of nonapeptide hormones (including isotocin in teleost fish) is thought to play an important role in regulating social behaviour across a wide range of taxa and social contexts. In the current study, we investigated the influence of exogenous administration of isotocin and an oxytocin receptor antagonist on sociality in a cooperatively breeding fish, Neolamprologus pulcher. In our first experiment, we found that a high (and a low) dose of peripherally administered exogenous isotocin decreased the time spent associating with conspecifics in N. pulcher, while an intermediate dose had no effect relative to control. In our second experiment, we found that a peripheral administration of an oxytocin receptor antagonist increased grouping preference in male N. pulcher. The results of both experiments suggest that IT may inhibit grouping behaviour in this species. These results contribute to a growing body of literature suggesting that the broad generalization that the oxytocin family of nonapeptides facilitate grouping behaviour is overly simplistic, and that specific behavioural effects depend the study species and testing conditions.

scholarly journals A test of male infanticide as a reproductive tactic in a cichlid fish

2017 ◽  
Vol 4 (3) ◽  
pp. 160891 ◽  
Author(s):  
Shagun Jindal ◽  
Aneesh P. H. Bose ◽  
Constance M. O'Connor ◽  
Sigal Balshine
Keyword(s):  
Cichlid Fish ◽  
Group Living ◽  
Laboratory Setting ◽  
Dominant Position ◽  
Egg Cannibalism ◽  
Cooperatively Breeding ◽  
Dominant Individual ◽  
Living Species ◽  
Reproductive Tactic ◽  
Relative Body Size

Infanticide and offspring cannibalism are taxonomically widespread phenomena. In some group-living species, a new dominant individual taking over a group can benefit from infanticide if doing so induces potential mates to become reproductively available sooner. Despite widespread observations of infanticide (i.e. egg cannibalism) among fishes, no study has investigated whether egg cannibalism occurs in fishes as a result of group takeovers, or how this type of cannibalism might be adaptive. Using the cooperatively breeding cichlid, Neolamprologus pulcher , we tested whether new unrelated males entering the dominant position in a social group were more likely to cannibalize eggs, and whether such cannibalism would shorten the interval until the female's next spawning. Females spawned again sooner if their broods were removed than if they were cared for. Egg cannibalism occurred frequently after a group takeover event, and was rarer if the original male remained with the group. While dominant breeder females were initially highly aggressive towards newcomer males that took over the group, the degree of resistance depended on relative body size differences between the new pair and, ultimately, female aggression did not prevent egg cannibalism. Egg cannibalism, however, did not shorten the duration until subsequent spawning, or increase fecundity during subsequent breeding in our laboratory setting. Our results show that infanticide as mediated through group takeovers is a taxonomically widespread behaviour.

scholarly journals First- and second-order sociality determine survival and reproduction in cooperative cichlids

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151971 ◽  
Author(s):  
Arne Jungwirth ◽  
Michael Taborsky
Keyword(s):  
Social Organization ◽  
Group Size ◽  
Reproductive Output ◽  
Local Population ◽  
Cichlid Fish ◽  
Evolution Of Cooperation ◽  
Large Group ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Different Levels

Cooperative breeders serve as a model to study the evolution of cooperation, where costs and benefits of helping are typically scrutinized at the level of group membership. However, cooperation is often observed in multi-level social organizations involving interactions among individuals at various levels. Here, we argue that a full understanding of the adaptive value of cooperation and the evolution of complex social organization requires identifying the effect of different levels of social organization on direct and indirect fitness components. Our long-term field data show that in the cooperatively breeding, colonial cichlid fish Neolamprologus pulcher , both large group size and high colony density significantly raised group persistence. Neither group size nor density affected survival at the individual level, but they had interactive effects on reproductive output; large group size raised productivity when local population density was low, whereas in contrast, small groups were more productive at high densities. Fitness estimates of individually marked fish revealed indirect fitness benefits associated with staying in large groups. Inclusive fitness, however, was not significantly affected by group size, because the direct fitness component was not increased in larger groups. Together, our findings highlight that the reproductive output of groups may be affected in opposite directions by different levels of sociality, and that complex forms of sociality and costly cooperation may evolve in the absence of large indirect fitness benefits and the influence of kin selection.

Cooperatively breeding cichlid fish adjust their testis size but not sperm traits in relation to sperm competition risk

2008 ◽  
Vol 62 (11) ◽  
pp. 1701-1710 ◽  
Author(s):  
Satoshi Awata ◽  
Tomohiro Takeyama ◽  
Yoshimi Makino ◽  
Yuko Kitamura ◽  
Masanori Kohda
Keyword(s):  
Sperm Competition ◽  
Cichlid Fish ◽  
Testis Size ◽  
Cooperatively Breeding ◽  
Sperm Competition Risk ◽  
Sperm Traits
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