title: Cooperative growth regulation in coral-dwelling fishes.
abstract: Dominant individuals often grow faster than subordinates because they gain a greater share of important resources. However, dominants should also strategically adjust their growth rates, relative to the size of subordinates, if this improves their reproductive success. Here, we show that individuals in breeding pairs of the coral-dwelling fish Gobiodon histrio regulate their growth to reduce the size difference between partners. In pairs where one individual was larger than the other, the smaller individual increased its growth rate and the larger individual decreased its growth rate, compared to individuals in size-matched pairs. The reproductive success of breeding pairs is limited by the size of the smallest individual in the pair. Therefore, it appears that the larger individual trades-off its own growth against that of the smaller individual, thereby improving the reproductive success of both individuals in the pair. This demonstrates a remarkable ability of individuals to strategically adjust their body size to suit the local social environment, and reveals a novel mechanism for size-assortative mating.
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, School of Marine Biology and Aquaculture, James Cook University, Townsville, Queensland 4811, Australia. philip.munday@jcu.edu.au
authors.forename: Philip L
authors.initials: PL
authors.lastname: Munday
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Cardoni
authors.forename: Craig
authors.initials: C
authors.lastname: Syms
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D037421:Anthozoa; D049628:Body Size; D005260:Female; D008297:Male; D010473:Perciformes / Q000502:physiology*; D012098:Reproduction; D019849:Sex Determination Processes; D012726:Sexual Behavior, Animal; D012741:Sexual Maturation / Q000502:physiology*; D012931:Social Environment