Behavioural traits of colony founders affect the life history of their colonies

Abstract

Social arthropods are a major feature in terrestrial ecosystems, and understanding the factors leading to their success is of broad interest. Although many studies have attempted to link colonies' phenotypic composition with their productivity, no study has linked phenotypic composition with the number of offspring colonies formed in the field. I tested whether the behavioural composition of newly founded colonies predicted colony life history patterns in the social spider Anelosimus studiosus. Individual A. studiosus exhibit either an 'aggressive' or 'docile' behavioural type (BT) and BT composition varies among colonies. I constructed artificial colonies of known BT composition and monitored their performance under two conditions: (1) foreign heterospecific spiders present and (2) foreign spiders removed. When heterospecifics were present, colonies founded by docile individuals were invaded by heterospecific spiders more quickly, grew more rapidly in size, produced more offspring colonies per year, but suffered reduced longevity. The life history trade-offs (reproduction, longevity) experienced by colonies resemble those experienced by individuals.