1. Chapter 9: Kinship Kinship Theory Conflict within Families
Kin Recognition

2. Belding’s Ground Squirrels: Females give more alarm calls
FIGURE 9.1a. Alarm calling in squirrels. In Belding’s ground squirrels, females (A) are much more likely than males to emit alarm calls when predators are sighted. Such alarm calls warn others, including female relatives and their pups (B). (Photo credits: George D. Lepp; Paul W. Sherman)
Belding’s Ground Squirrels:
Females give more alarm calls
Males leave natal area to find mates, females do not

3. FIGURE 9. 2. Ground squirrel alarm calls
FIGURE 9.2. Ground squirrel alarm calls. When comparing the observed (orange bars) versus the expected (green bars) frequencies of alarm calls in Belding’s ground squirrels, females emit such calls at a rate greater than that expected by chance (p < .001). As a result of dispersal differences across sexes, females, but not males, are often in kin-based groups. (From Sherman, 1977)

4. FIGURE 9. 3. Kin selection and ground squirrels
FIGURE 9.3. Kin selection and ground squirrels. Belding’s ground squirrel groups are typically made up of mothers, daughters, and sisters that cooperate with one another in a variety of contexts. Males that emigrate into such groups cooperate to a much smaller degree. (Based on Pfennig and Sherman, 1995)

5. Daly and Wilson (1988) genetic relative rarely kill each other.
TABLE 9.1. Risk of homicide in cases where the victim and offender were cohabitants in Detroit in 1972.
Daly and Wilson (1988) genetic relative rarely kill each other.

6. W. D. Hamilton (1963 and 1964)
“Inclusive Fitness” - the fitness of an individual organism as measured in terms of the survival and reproductive success of its kin, each relative being valued according to the probability of shared genetic information, an offspring or sibling having a value of 50 percent and a cousin 25 percent.
JBS Haldane (according to John Maynard Smith), “I would gladly give up my life for two brothers or eight cousins.”

7. FIGURE 9. 5. Pedigrees for calculating relatedness
FIGURE 9.5. Pedigrees for calculating relatedness. Individuals X and Y may have one or two most recent common ancestors (dark shading). (A) X and Y have the same grandmother but different grandfathers. Thus, their grandmother is their sole most recent common ancestor. (B) X and Y have the same maternal grandmother and the same maternal grandfather. Thus, maternal grandparents are the most recent common ancestors. (From Bergstrom and Dugatkin, 2012)

8. FIGURE 9.6. Example pedigrees for computing coefficients of relatedness. (A) X and Y are half siblings. (B) A more complicated scenario, in which X and Y come from different generations. Here, Y is X’s aunt. (From Bergstrom and Dugatkin, 2012)

9. FIGURE 9. 7. The effects of helping kin
FIGURE 9.7. The effects of helping kin. In grey-crowned babblers (Pomatostomus temporalis), reproductive success, as measured by the number of fledglings, was significantly lower in the experimental groups because they had fewer helpers. Helpers increased the reproductive success of others—their kin— in their group (Based on Brown et al., 1982)

10. FIGURE 9. 8. Evolutionary theory of family
FIGURE 9.8. Evolutionary theory of family. Emlen’s evolutionary theory of family is generated by combining inclusive fitness, reproductive skew, and ecological constraints theory.

11. FIGURE 9. 9a. Group structure of lowland gorillas
FIGURE 9.9a. Group structure of lowland gorillas. (A) A group of lowland gorillas. (B) BG = breeding group, NBG = nonbreeding group, ? = unknown group structure. Over the course of their lives, most males will be part of all three group structures. (Photo credit: Christophe Courteau/naturepl.com; from Levrero et al., 2006)

12. TABLE 9.2. Predictions generated by the evolutionary theory of the family model.

13. FIGURE 9. 10. Superb fairy wren
FIGURE Superb fairy wren. In superb fairy wrens, young males often act as helpers-at-the-nest. When breeding males are removed from their territories, almost all potential male helpers that could have dispersed to newly opened territories did so. (Photo credit: Graeme Chapman)
Emlen’s Prediction One: Family groupings will be unstable, disintegrating when acceptable reproductive opportunities materialize elsewhere.

14. FIGURE Family breakup. In the superb fairy wren, male helpers often assist their parents. If a vacant territory opens up, however, male helpers are quick to leave the family unit and attempt to start their own family.

15. Emlen’s Prediction Two: Families that control high-quality resources will be more stable than those with lower-quality resources.
Family dynasties in resource-rich areas

16. Emlen’s Prediction Four: Assistance in rearing offspring (cooperative breeding) will be expressed to the greatest extent between those family members that are the closest genetic relatives.

17. FIGURE 9. 16. Phylogeny of ant, bee, and wasp species
FIGURE Phylogeny of ant, bee, and wasp species. Ethologists have predicted that eusociality in bees should often be associated with a monandrous mating system. The phylogeny shown here is for ants, bees, and wasps for which data on female mating frequency are available. Each independent origin of eusociality is indicated by alternately colored—blue or orange—clades. (A clade is a taxonomic grouping including an ancestral group and its descendants.) Cases of high polyandry are depicted by red branches, and completely monandrous groups are shown with black branches. All eight clades here have monandry as the ancestral state. (Adapted from Hughes et al., 2008)

18. FIGURE 9. 17a. Honeybee policing
FIGURE 9.17a. Honeybee policing. (A) While the queen (designated by the red dot on her back) typically lays the eggs in a honeybee colony, workers also attempt to lay unfertilized eggs. (B) When an egg laid by a worker is detected by worker police, it is eaten or destroyed. Workers are much more likely to destroy eggs produced by other workers than eggs produced by the queen. Such “policing” has inclusive fitness benefits associated with it. (Photo credits: Francis Ratnieks)

19. FIGURE 9. 17b. Honeybee policing
FIGURE 9.17b. Honeybee policing. (A) While the queen (designated by the red dot on her back) typically lays the eggs in a honeybee colony, workers also attempt to lay unfertilized eggs. (B) When an egg laid by a worker is detected by worker police, it is eaten or destroyed. Workers are much more likely to destroy eggs produced by other workers than eggs produced by the queen. Such “policing” has inclusive fitness benefits associated with it. (Photo credits: Francis Ratnieks)

20. FIGURE 9. 18. Worker policing in honeybees
FIGURE Worker policing in honeybees. In honeybees, where queens often mate with ten to twenty males, workers are more related to the male offspring of the queen (their brothers) than to offspring of other workers (their nephews). Workers police the hive and search out and eat the eggs of other workers. (From Ratnieks and Visscher, 1989)

21. FIGURE Wasp policing. In the wasp Dolichovespula saxonica, workers often lay (haploid) eggs, in nests with both single-mated and multiply mated queens. Such eggs are often eaten when detected by other workers. (A) The wasp in the middle of the photo is a worker that has just laid an egg. (B) Here a worker is eating another worker’s egg. Policing is much more common in wasp colonies where the queen has mated with many males. (Photo credits: Kevin Foster)

22. CONFLICT
Parent-Offspring Conflict

23. FIGURE 9. 21. Parent/offspring conflict
FIGURE Parent/offspring conflict. Parents can provide resources to a “focal” offspring or use those resources on other current or future offspring. The x-axis shows the resources invested in the focal offspring, and the y-axis shows fitness costs (c) or benefits (b). The parent is equally related to all of its offspring, but the focal offspring is only half as related to its full siblings as it is to itself. As a result, parent and offspring prefer different amounts of resource allocation. This zone of conflict is shaded in the figure. To the left of the zone, parents and offspring alike benefit from increasing allocation to the offspring. To the right of this zone, parents and offspring alike benefit from decreasing allocation to the offspring.

24. FIGURE 9. 23a. Mothers and babies
FIGURE 9.23a. Mothers and babies. While the parent-offspring relationship is usually cooperative (A), parent-offspring conflict can occur, even in utero (B). (Photo credits: Ariel Skelley/Corbis; Science VU/ Visuals Unlimited)

25. FIGURE 9. 23b. Mothers and babies
FIGURE 9.23b. Mothers and babies. While the parent-offspring relationship is usually cooperative (A), parent-offspring conflict can occur, even in utero (B). (Photo credits: Ariel Skelley/Corbis; Science VU/ Visuals Unlimited)

26. CONFLICT
Sibling Rivalry

27. FIGURE 9. 24. Sib-sib conflict
FIGURE Sib-sib conflict. Kin selection theory predicts that individuals should not be very aggressive toward kin such as sibs, especially when there are abundant resources. But if there are limited resources, conflict over the resources will increase, because each individual is more related to itself (r = 1) than to its sib (r = 0.5).

28. FIGURE 9. 25. Sib-sib competition in birds
FIGURE Sib-sib competition in birds. In nests of egrets, sib-sib competition can be intense and can result in the death of smaller, less dominant chicks. Sibling rivalry can be seen in the fights between siblings in the nest, as shown here, where the chick on the left is preparing to bite its sibling on the back of its head. (Photo credit: Millard H. Sharp/ Photo Researchers, Inc.)

29. FIGURE 9. 26. Birth order and food intake
FIGURE Birth order and food intake. (A) Normal broods of little blue herons include four to five chicks that are hatched asynchronously. (B) In egret broods, the oldest, dominant chick (1) receives more food than the middle chick (2), who in turn gets more than the youngest chick (3). This holds for the early period after hatching (1–13 days), the middle period (14–21 days), and the late period (21–30 days). (Based on Mock and Parker, 1997)

30. KIN RECOGNITION
Matching Models

31. FIGURE 9. 27a. Kin recognition in penguins
FIGURE 9.27a. Kin recognition in penguins. Kin recognition via vocal signatures has been examined in (A) the emperor penguin (Aptenodytes forsteri) and (B) the king penguin (Aptenodytes patagonicus). Both species of penguins live in large colonies, and parents returning from foraging with food for their chicks use vocal cues to find their offspring in the middle of many other chicks. (Photo credits: Hans Reinhard/Photo Researchers, Inc.)

32. FIGURE 9. 27b. Kin recognition in penguins
FIGURE 9.27b. Kin recognition in penguins. Kin recognition via vocal signatures has been examined in (A) the emperor penguin (Aptenodytes forsteri) and (B) the king penguin (Aptenodytes patagonicus). Both species of penguins live in large colonies, and parents returning from foraging with food for their chicks use vocal cues to find their offspring in the middle of many other chicks. (Photo credits: Hans Reinhard/Photo Researchers, Inc.)

33. FIGURE 9. 28. Tadpole cannibals
FIGURE Tadpole cannibals. As in the spadefoot toad, two different tadpole morphs—a carnivorous cannibal and an herbivorous omnivore—exist in a number of amphibian species. Here a tiger salamander (Ambystoma tigrinum) cannibal morph (right) is eating an omnivore morph (left). (Photo credit: David Pfennig)

34. FIGURE 9. 29. Kin recognition in spadefoot toads
FIGURE Kin recognition in spadefoot toads. Spadefoot toad tadpoles come in two morphs: carnivorous and herbivorous. Individuals from each tadpole morph were placed between two groups of tadpoles, one of which contained sixteen unfamiliar siblings, the other of which was composed of unfamiliar nonsiblings. (Based on Pfennig et al., 1993)

35. FIGURE 9. 30. Hunger and carnivorous toads
FIGURE Hunger and carnivorous toads. The carnivorous morph of spadefoot toads prefers to eat nonkin over kin. When carnivorous morphs were starved for 24 hours (A), only a little more than 10 percent of individuals eaten were kin. If they were starved for 48 hours, this figure rises. As a control, toads were again starved for 24 hours (C), and results were similar to the original 24-hour deprivation treatment (A). (Based on Pfennig et al., 1993)

36. KIN RECOGNITION
Rule of Thumb: If it’s in your nest, treat it like kin
Two Cuckoo Finch eggs with one Fantail Warbler egg!