A comparison of techniques for assessing dispersal behaviour in gundis: revealing dispersal patterns in the absence of observed dispersal behaviour

Abstract

Knowledge of the dispersal status of group members is important to understanding how sociality may have evolved within a species. I assessed the effectiveness of four techniques for elucidating dispersal behaviour in a rock-dwelling rodent (Ctenodactylus gundi) with small group sizes (2-10 animals): genetic parentage assignment, haplotype data and kinship analyses, assignment testing, and F-statistics. The first two methods provided the greatest insight into gundi dispersal behaviour. Assignment testing and F-statistics proved of limited use for elucidating fine-scale dispersal, but could detect large-scale patterns despite low sex-biased dispersal intensity (1.9 : 1) because of moderate genetic differentiation among groups (F ST = 0.10). Findings are discussed in light of current dispersal theory. In general, gundi dispersal is plastic, and seems to be dependent on body weight (for males), group composition, and scale of analysis (total dispersal events recorded within the population were almost twice the immigration rate into the population). Most groups were comprised of a single matriline and one immigrant male. Immigrant rather than philopatric males bred with group females. Dispersal among groups was male-biased, but dispersal or philopatry could occur by either sex. During a drought, both sexes delayed dispersal and cooperative social units formed. Whether such behaviour resulted directly from the drought or not remains unclear, however, since comparative information was not available from nondrought years. Combining fine-scale analyses with information on large-scale patterns provided substantial insight into gundi dispersal behaviour despite the limited movement of animals during a drought, and may prove useful for elucidating dispersal behaviour in other social animals.

Scale-Specific Sex-Biased Dispersal in the Valais Shrew Unveiled by Genetic Variation on the Y Chromosome, Autosomes, and Mitochondrial Dna

“…Similarly, Gauffre et al (2009) showed that male common voles ( Microtus arvalis ) disperse much more than females at a local scale (within colonies), but that dispersal at a larger scale is balanced among sexes. A similar pattern was found in another rodent ( Ctenodactylus gundi ) by Nutt (2008). Finally, Douadi et al (2007) found that both male and female western lowland gorillas ( Gorilla gorilla gorilla ) disperse among breeding groups, but that only males disperse at a larger spatial scale.…”

“…Finally, Douadi et al (2007) found that both male and female western lowland gorillas ( Gorilla gorilla gorilla ) disperse among breeding groups, but that only males disperse at a larger spatial scale. Some of these studies were primarily based upon autosomal data (nuclear microsatellites), others used mtDNA haplotypes (Nutt 2008) or a combination of mtDNA and Y‐linked data (Douadi et al 2007). Combining genetic data from the Y chromosome and from mtDNA should prove especially powerful to identify such scale‐dependent sex‐linked differences in dispersal.…”

Between-Group Variation in Female Dispersal, Kin Composition of Groups, and Proximity Patterns in a Black-and-White Colobus Monkey (Colobus vellerosus)

“…Sometimes the patterns of sex bias in dispersal differ between these two variables [59], [60], [61]. Future studies should therefore investigate dispersal distance in addition to dispersal frequency, which may require relocating dispersing animals and sampling animals in the surrounding groups in the main fragment as well as surrounding fragments [61], [62], [63], [64].…”

A comparison of four methods for detecting weak genetic structure from marker data

“…Consequently, using genetic data alone, it is possible to make inferences about gene flow and therefore dispersal behavior. Following this, inferences can be made about the mating system, social and phylogeographic structure, and population dynamics of the population (Nutt 2008). These inferences provide vital information for the effective management of endangered species.…”