Manipulation of population density and food availability affects home range sizes of African striped mouse females. (January 2015)

• Record Type: Journal Article
• Authors: Schoepf, Ivana; Schmohl, Gabriela; König, Barbara; Pillay, Neville; Schradin, Carsten
• Is Part Of: Animal behaviour. Volume 99(2015)
• Page Start: 53
• Page End: 60
• Publication Date: 2015-01
• Subjects: communal breeding -- cooperative breeding -- group living -- philopatric -- resource availability -- resource defence -- roamer -- social flexibility -- solitary living -- spatial use; Animal behavior -- Periodicals; 591.5
• DOI: 10.1016/j.anbehav.2014.10.002
• Languages: English
• ISSNs: 0003-3472

Abstract

Abstract : An individual's home range determines its access to resources, significantly influencing its fitness. Food availability and population density are considered to be among the primary factors influencing home range sizes; however, no study has experimentally tested whether these two factors affect home range sizes independently. This is important as these two factors correlate significantly with each other, making it difficult to differentiate the effect of one from the other. First, we supplemented food to 23 female African striped mice, Rhabdomys pumilio, belonging to 15 different groups. To avoid an increase in population density by immigration, we also provided food to neighbouring groups. Although population density did not increase, female home range sizes decreased by 43.1%. In a second experiment, we manipulated population density by removing entire social groups of striped mice. We carried out experiments within 7 weeks, a period short enough to control for a change in natural food availability. Experimental decrease of population density caused an increase of female home range sizes of 44.3%. The degree of home range overlap between female striped mice was unaffected by supplemental feeding or by reduction of population density. However, female home range sizes were negatively affected by the total number of female neighbours, especially of heavier individuals. In addition, after removal, females significantly decreased their overlap with neighbouring breeding females indicating that competition with same-sex individuals shapes females' home ranges. This is the first comprehensive experimental field study demonstrating that an increase in food availability and a decrease in population density independently affect home range sizes of individuals. Highlights: Food availability and population density affect home ranges, but they are also correlated. Using field experiments we manipulated one factor while controlling for the other. When we provided food, home ranges decreased by 43.1%. When we removed neighbours, home ranges increased by 44.3%. Home ranges are independently affected by food availability and population density.