Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017
Erindi/veggspjald / Talk/poster V65
Höfundar / Authors: David Benhaïm, Bjarni K. Kristjánsson & Camille A.-L. Leblanc
Starfsvettvangur / Affiliations: Department of Aquaculture and Fish Biology, Hólar University College, Sauðárkrókur, Iceland
Kynnir / Presenter: Louise Vernier
Polymorphism, the occurrence of two or more distinct phenotypes of a same species, is the result of evolutionary and ecological processes. Arctic charr, a Northern freshwater fish, is a good model to study resource polymorphism due to its high level of intra-specific diversity. Pairs of sympatric resource-based morphs are commonly found within lakes. Differences in egg size, morphology, behaviour, parasite load, and growth have been found between these morphs. However, little is known about the connection between egg size and long lasting phenotypic differences of individuals across morphs.
Here we explore the relationship between egg size, body size and behaviour at the individual level in Arctic charr juveniles. Five morphs of Arctic charr were selected along a gradient of genetic and phenotypic divergence, ranging from an anadromous population to a pair of reproductively isolated sympatric morphs. Progeny of known egg sizes were raised individually for one year and followed for survival, developmental rate, growth, and ultimately tested for exploratory behaviour and boldness.
Egg size and body length were found to be positively correlated soon after hatching in all morphs. This correlation disappeared at 11 months old, except in the little diverged sympatric morphs. Relationship between behaviour and egg size/body size was observed in the anadromous morph. Highly diverged sympatric morphs showed higher within-morph and between-morph variation in egg size, body size and behaviour than little diverged morphs, while the anadromous morph showed the highest within-morph variation in all observed traits.
The results of this study highlight how individual differences in size at early life stages may have long lasting implications for growth and behaviour of individuals within and across morphs of different levels of divergence. Ultimately, allometric differences may promote and/or maintain phenotypic diversity in behaviour.