Figure 13.1 Energy budget of subordinate, nonbreeding “helpers” that associate with breeding pairs in the cichlid fish Neolamprologus pulcher

Figure 13.2 Effect of removal of the top-ranked subordinate helper in a cooperatively breeding group of cichlid fish

Figure 13.4 Competition for food is a cost of sociality in the fieldfare

Brown and Brown 1986

Figure 13.5 Effect of parasites on cliff swallow nestlings

Figure 13.6 Social living with defensive benefits?

Figure 13.7 Mutual defense in a society of bluegills

Gross and MacMillan 1981

Figure 13.8 The different categories of helping behavior

Figure 13.9 Cooperation among competitors

Greene et al 2000

Greene et al. 2000

Figure 13.12 A meerkat sentinel on the alert for approaching predators

Figure 13.13 Experimental demonstration of reciprocity in cotton-top tamarins

Figure 13.14 The prisoner’s dilemma

Wilkinson 1990

Wilkinson 1984

Figure 13.15 The components of selection and fitness

Figure 13.16 Sibling pairs of the cichlid fish Pelivicachromis taeniatus cooperate more than unrelated males and females when it comes to guarding a nest containing their eggs

Figure 13.17 A Belding’s ground squirrel gives an alarm call after spotting a terrestrial predator

Figure 13.18 Altruism and relatedness in pied kingfishers

Figure 13.24 Cooperative breeding in African starlings is associated with species that live in savanna grasslands

Figure 13.25 Haplodiploid sex determination in Hymenoptera

Figure 13.27 Are workers in social insect colonies forced to be altruistic? (Part 1)

Figure 13.27 Are workers in social insect colonies forced to be altruistic? (Part 2)

Figure 13.33 Foundress females and workers of the paper wasp Polistes metricus have a similar pattern of gene activity, whereas future reproductives and queens exhibit very different patterns

Figure 13.34 Eusociality has an evolutionary history

Figure 13.36 Haplodiploidy and the evolution of eusociality in the Hymenoptera (Part 1)

Figure 13.36 Haplodiploidy and the evolution of eusociality in the Hymenoptera (Part 2)

Figure 13.40 Indirect selection and the origin of eusociality in the Hymenoptera