| Popis: |
The suborder Hystricomorpha is an ideal model group for the study of rodent life-history evolution due to its wide distribution, great diversity of inhabited ecosystems and social systems. By tracking several factors, it was possible to determine the key factors that influenced litter size during evolution. The data set contained 75 of the total 292 species of the suborder. The average litter size, female and male body size, level of sexual dimorphism, level of sociality, type of reproductive system, level of parental care, presence of multipaternity, type of habitat and food were assigned to each species based on the information obtained from the available literature. The analysis included a statistical part calculated using general linear mixed models, and a phylogenetic part including parsimonious mapping of characters onto the phylogenetic tree and linear regression using phylogenetic independent contrasts. Social factors like degree of sociality, sexual dimorphism and reproductive system significantly influenced litter size at birth. Multipaternity also had an influence, but less than the first three factors. Ecological factors, food and environment, had no effects unless they were combined with the effect of family. It is therefore possible to assume that ecological factors have influenced... |
