Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate

Abstract

1. Individuals vary in their ability to disperse. Much of this variation can be described bycovarying phenotypic traits that are related to dispersal (constituting the ‘dispersal phenotype’or ‘dispersal syndrome’), but the nature of the associations among these traits is not wellunderstood. Unravelling the associations among traits that potentially constitute the dispersalphenotype provides a foundation for understanding evolutionary trade-offs due to variation indispersal.2. Here, we tested five predictions pertaining to the relationships among physiological, mor-phological and movement traits that are associated with dispersal, using a species with a longhistory as a laboratory model for studying ecological phenomena, red flour beetles (Triboliumcastaneum).3. We identi fied a dominant axis of movement ability that describes variation in dispersal-related movement traits. Individuals that scored positively on this axis moved at higher speed,travelled longer distances, had lower movement intermittency and dispersed quicker to aspecified area.4. Relative leg length, but not body size nor routine metabolic rate related positively withmovement ability, indicating a likely mechanistic relationship between increased stride lengthand movement ability. 5. Our data suggest that the dispersal phenotype may be more strongly linked to morphologi-cal traits than physiological ones. We demonstrate that associations among many functionaltraits do not necessarily conform to a priori expectations, and predict that the substantialintraspecific variation in trait values may be important for selection. Movement is a complexbehavioural trait, but it has a mechanistic basis in locomotor morphology that warrantsfurther exploration. Show more