What costs can animals face when they live in colonies?

Living in colonies provides animals with benefits like improved predator detection and resource access, but it also introduces significant costs due to the close proximity of other individuals. These costs include:1

• Health and Parasitism: Close contact increases the risk of contracting disease and becoming susceptible to parasitism, particularly from ectoparasites like fleas and ticks.1
• Resource Competition: Animals in colonies face increased competition for food, which can lead to kleptoparasitism (food stealing). Additionally, individuals may need to travel greater distances to find foraging areas as local resources are depleted.1
• Reproductive Costs: Coloniality can facilitate conspecific brood parasitism, where females lay eggs in the nests of others, and increase the risk of extra-pair matings, which can be costly to the cuckolded males.1
• Social Conflict: Dominant individuals may monopolize resources, making group living less beneficial for subordinates. Furthermore, close proximity increases the risk of cannibalism and injury during social interactions.1