Albia Dugger Miami Dade College Cecie Starr Christine Evers Lisa Starr Chapter 39 Animal Behavior (Sections )

39.5 Communication Signals Communication signals play a role in both cooperative and competitive behavior communication signal Chemical, acoustical, visual, or tactile cue that is produced by one member of a species and detected and responded to by other members of the same species

Communication Signals (cont.) Pheromones are chemical signals Examples: honeybee alarm pheromone, sex attractants, priming pheromones Bird song and other animal calls are acoustical signals Attracts mates, defines territories, conveys alarms

Communication Signals (cont.) A male baboon’s threat display is a visual signal that communicates readiness to fight a rival

Communication Signals (cont.) Most bird courtship involves coordinated visual signaling

Communication Signals (cont.) Dogs and wolves signal play behavior with a play bow

Communication Signals (cont.) Honeybees use tactile signals to communicate the distance to a food source, and its direction relative to the sun

Fig c, p. 663 When bee moves straight up comb, recruits fly straight toward the sun. Communication Signals (cont.)

Fig d, p. 663 When bee moves straight down comb, recruits fly to source directly away from the sun. Communication Signals (cont.)

Fig e, p. 663 When bee moves to right of vertical, recruits fly at 90° angle to right of the sun. Communication Signals (cont.)

Honeybee Dances

Fig a, p. 663 Honeybee Dances

Fig b, p. 663 Honeybee Dances

Fig , p. 663 Stepped Art When bee moves straight up comb, recruits fly straight toward the sun. When bee moves straight down comb, recruits fly to source directly away from the sun. When bee moves to right of vertical, recruits fly at 90° angle to right of the sun. CDE Honeybee Dances

ANIMATION: Honeybee dances To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

Adaptations by Predators Predators sometimes use the signaling systems of their prey against them Frog-eating bats follow the frogs’ mating calls to find food Predatory female fireflies imitate flashing of prey species to attract food

Key Concepts Animal Communication Animal communication behavior can only evolve if communication benefits both signal senders and signal receivers Animals communicate by a variety of mechanisms Predators sometimes take advantage of the communication behavior of their prey

39.6 Mates, Offspring, and Reproductive Success Sexual selection occurs when males or females of a species compete for access to mates, or when they are choosy about their mates Parenting behaviors can also reflect different selective pressures operating on males and females

Mating Behavior Sexual selection favors characteristics that provide a competitive advantage in attracting and retaining mates Males usually maximize their reproductive success by mating as many times as possible Females are more likely than males to turn down opportunities to breed with a low-quality individual

Sexual Selection Male hangingfly offers a moth to a potential mate Female hangingflies only breed with males who provide an energy- laden meal

Sexual Selection Female fiddler crabs choose mates with large claws who have built a burrow with the right location and size

Sexual Selection Male grouse converge at a lek to attract a mate by displaying, dancing and calling lek Of some birds, a communal mating display area for males

Mating Behavior (cont.) In species such as lions, elk, elephant seals, and bison; females cluster around a necessary resource, and males may hold a territory that they defend from others The territory holder mates with all females in his territory territory Region that an animal or animals occupy and defend against competitors

Male Bison Defending his Territory

Mating Behavior (cont.) When females choose among a group of displaying males or males defend a mating territory, nearly all females mate but many males do not These systems impose strong selective pressure for mating- related traits on males (sexual dimorphism) sexual dimorphism Distinct male and female phenotypes Example: Large claws in male fiddler crabs

Parental Care Evolution of parental care requires that benefits to a parent (increased offspring survival) be greater than the cost (lost reproductive opportunity) Mammals are usually born in a helpless state, so parental care is essential – typically, the female is the sole caregiver Example: A female grizzly bear cares for her cub for as long as two years; the male takes no part in its upbringing

Female Grizzly and Cub

Parental Care (cont.) Males seldom serve as sole caregivers The midwife toad is an exception: a male holds fertilized eggs around his legs until the eggs hatch

Parental Care (cont.) Most birds are monogamous, and parents cooperate in caring for young Example: Caspian terns

Key Concepts Mating and Parenting Males and females maximize their reproductive success in different ways Females tend to be choosier about mates than males Monogamy is rare among animals, but it tends to correlate with parental care by both parents More often, the female provides parental care

39.7 Living in Groups Many animals benefit by clustering in groups Birds, monkeys, meerkats, and other animals in social groups make alarm calls in response to a predator Example: Prairie dog

Defense Against Predators Sawfly caterpillars benefit by the group’s coordinated response to predators Predatory birds to avoid the mass of fluid- exuding caterpillars, preferring to attack individuals

Defense Against Predators When animals cluster, some individuals shield others from predators – preference for the center of a group can create a selfish herd, in which individuals hide behind one another selfish herd Temporary group that forms when individuals cluster to minimize their individual risk of predation

Defense Against Predators: Musk Oxen Protecting Young

Improved Feeding Opportunities Many mammals (such as wolves, lions, wild dogs, and chimpanzees) live in social groups and cooperate in hunts Cooperative hunters are not more efficient than solitary ones; the major advantage of group living lies in help fending off scavengers, caring for one another’s young, and protecting territory together

Wolf Pack Hunting

Feeding Opportunities (cont.) Group living also allows transmission of cultural traits, or behaviors learned by imitation Example: Chimpanzees make and use simple tools They use thick sticks to make holes in a termite mound, then insert long, flexible “fishing sticks” into the holes Different groups of chimpanzees use slightly different tool- shaping and termite-fishing methods Youngsters learn by imitating adults

Behavior Learned by Imitation

Dominance Hierarchies Many animals in permanent groups form a dominance hierarchy in which dominant animals get a greater share of resources and breeding opportunities than subordinate ones Example: In wolf packs, usually only the alpha male and alpha female breed; subordinates get their chance to reproduce by outliving a dominant peer dominance hierarchy Social system in which resources and mating opportunities are unequally distributed within a group

Regarding the Costs In most habitats, costs of social living outweigh the benefits Large social groups attract more predators Individuals that live in dense groups have higher risks of parasites and contagious diseases, and compete more for resources Example: Seabirds in dense breeding colonies

Crowded Penguin Breeding Colony

Video: Wolf Pack

39.8 Why Sacrifice Yourself? Extreme cases of sterility and self-sacrifice have evolved in a few insects and one group of mammals Ants, termites, honeybees, and mole-rats are eusocial – they live in colonies with overlapping generations and have a reproductive division of labor Most colony members do not reproduce; they assist their relatives instead

Sterile Workers Workers often are highly specialized in form and function Example: Australian honeypot ant worker

Sterile Workers

Honeybees A queen honeybee is the only fertile female in her hive Sterile female workers feed larvae, clean and maintain the hive, construct honeycomb, gather nectar and pollen, and will sacrifice themselves to guard the hive Male stingless drones (produced seasonally) subsist on food gathered by their worker sisters; and fly each day in search of a mate

Termites A termite queen specializes in egg production A king supplies the female with sperm A termite mound holds both sterile males and females Winged reproductive termites of both sexes develop seasonally

Social Mole-Rats Sterility and extreme self-sacrifice are uncommon in vertebrates – mole rats are the only example A reproducing female (“queen”) dominates the clan and mates with one to three males (“kings”) Sterile clan-members guard the colony; or excavate tunnels and chambers, find food, and carry it back to the queen, her mates, and her young

Three Queens

Evolution of Altruism A sterile worker in a social insect colony or a naked molerat clan shows altruistic behavior Inbreeding increases the genetic similarity among relatives and may play a role in mole-rat sociality According to the theory of inclusive fitness, genes associated with altruism are selected if they lead to behavior that promotes reproductive success of close relatives

Key Terms altruistic behavior Behavior that benefits others at the expense of the individual theory of inclusive fitness Genes associated with altruism can be advantageous if the expense of this behavior to the altruist is outweighed by the reproductive success of relatives

Key Concepts Costs and Benefits of Social Living Life in social groups has reproductive benefits and costs Not all environments favor the evolution of such groups Self-sacrificing behavior has evolved among a few kinds of animals that live in large family groups

39.9 Evolution and Human Behavior Calling a behavior “adaptive” does not mean “morally right,” it means a behavior increases reproductive success Example: Infanticide is morally repugnant, but it happens in all human cultures – when mothers lack resources to care for their children, they are more likely to harm them Evolutionary forces shape and influence human behavior – but humans can make moral choices about their actions

An Aggressive Defense (revisited) When a European queen bee mates with an Africanized drone, her offspring are just as aggressive as workers in a pure Africanized colony A cross between an Africanized queen and a European drone yields workers with an intermediate level of aggression Unfortunately, Africanized males outcompete European males for matings