Further studies of behaviour

1. Option E.6 Further studies of behaviour

2. E.6.1 Describe the social organization of honey bee colonies and one other non-human example. E.6.2 Outline how natural selection may act at the level of the colony in the case of social organisms. E.6.3 Discuss the evolution of altruistic behaviour using two non-human examples. E.6.4 Outline two examples of how foraging behaviour optimizes food intake, including bluegill fish foraging for Daphnia. E.6.5 Explain how mate selection can lead to exaggerated traits. E.6.6 State that animals show rhythmical variations in activity. E.6.7 Outline two examples illustrating the adaptive value of rhythmical behaviour patterns. Assessment statements

3. Two or more animals interacting with each other Some animals show limited interaction while others are extremely sociable Examples? Social organization

4. Nest above ground, usually inside a hollow tree Wax combs with individual compartments (cells) for storing honey and rearing young Each hive has one queen whose job it is to lay eggs Workers are also female, but sterile Workers search for nectar and pollen; make wax and honey; and feed and protect the young Workers live for about 6 weeks; queen up to 2 years Male honey bees (drones) develop from unfertilized eggs and mating with queen is only function Honey bee colonies

5. Queen lays eggs in cells • Unfertilized eggs = males • Fertilized eggs = females • All fed glandular secretions called royal jelly for the first few days • Larvae destined to be workers are then switched to a less nutritious diet of honey and pollen • Those destined to be queens continue to be fed royal jelly offspring

6. Secretions produced by queen to control the hive • Inhibit ovarian development in workers • Passed by licking pheromone from queen’s body and then transferring to food which is exchanged • Most colonies: 60,000 in number • If colony gets too large, queen leaves with “swarm” and establishes a new hive leaving a new young queen behind pheromones

7. “scout” bees find source of nectar and do a waggle dance to indicate the direction and distance of the source Another chemical is released from the mouth area when the colony is in danger and the signal is spread around to the others Source of food

8. Roles of bees in the social organization of the colony Life cycle video

9. Most of our knowledge attributed to Jane Goodall (ethologist) Highest order of chimp society is the community Made up of 40-60 members Party smaller group within the community Party may be all male, a family, or a nursery unit Make up of parties depends on the food supply Social organization in chimpanzees

10. Males • Highest ranking is 20-26 yrs old • Dominance determined by physical fitness and fighting ability • Strong social bonds exist • Important for keeping out intruders, hunting, and sharing food • Females • Dominance in females is linked to age • May migrate to other communities • Responsible for care of young hierarchy

11. Facial expressions Vocalizations Chimp Talk Communication among chimpanzees

12. Acts on entire honey bee colony, not individuals • Genes selected are those that promote social organization • Pheromones • How to find nectar • Making of wax • Taking care of young Natural selection

13. Worker bees are altruistic They help the queen produce offspring rather than reproduce themselves Kin selection causes the evolution of altruism Result is a decrease in fitness* of the altruist and an increase in the fitness of a close relative *ability to survive and reproduce altruism

14. Belding’s ground squirrel Live in mountains of southwest U.S. Preyed upon by hawks and coyotes When a predator approaches, one of the ground squirrels gives a high-pitched call which alerts the rest of the population to the nearby danger

15. Alarm squirrel (usually female) is more likely to be killed Females live close to their family, while males live afar Alarm squirrel does not increase its own fitness but it is increasing the fitness of its relatives If all the female’s close relatives are dead, she does not sound alarm calls

16. Naked mole rats Rat colonies can be up to 100 individuals Live in burrows in East Africa Workers make nesting chambers and forage for plant roots needed for food which it brings to queen Larger workers stay near queen and young

17. Queen suppresses the sexual behavior of the other females by secreting pheromones in her urine Also suppresses sexual behavior of the males by bullying except when she is in estrus (ovulating) Main predator is snake Queen will send workers to attack snake Workers are sacrificed so queen can live and preserve the genes of the family

18. What an animal eats is essential to survival and ability to reproduce Behavioral ecologists study foraging behaviors and predict how an animal will forage in a certain set of conditions They base their predictions on cost-benefit analysis of the behavior Cost – energy used to locate, catch, and eat food Benefit – calories of energy gained Foraging behavior optimizes food intake

19. Small mouth bass • Forages for either minnows or crayfish • Minnows have more energy per unit weight • Crayfish are easier to catch • Small mouth bass show no preference • Each may be optimal under different conditions

20. Bluegill sunfish • Eats Daphnia • Bluegill sunfish usually forage for the larger ones • They will select smaller Daphnia if the larger ones are too far away • Not selective when density of Daphnia is low • Selective for larger if high density

21. Scientific prediction & results • Prediction: Bluegills would eat large Daphnia 100% of the time • Results: bluegills only ate large Daphnia 57% of the time • Reasons? • Young bluegills not as efficient as the older ones • Lack of ability to see the size? • Lack of skill?

22. Mate selection leads to exaggerated traits • Females prefer more highly decorated males • Also size and shape of their tales • Largest tail signifies the healthiest bird with the best chance for healthy offspring • Quality of tail measured by number of eyespots that it has

23. Studies show that the more eyespots a peacock has the higher number of mates it has • Experiments show that offspring of males with larger tails and more eyespots are larger at birth and survive better in the wild • Could peacock tails become a disadvantage?

24. Reproductive rhythm Once a year coral release millions of gametes in a synchronized mass spawning ritual Predators overwhelmed with more food than they can eat Animals show rhythmical variations in activity

25. Feeding behavior • North American flying squirrel flies at night • Gets the most food and the least competition

26. Daily rhythms • Diurnal and circadian are both used to describe a 24-hour cycle of behavior • Behaviors are controlled internally (endogenous), but external (exogenous) cues such as light are important in sychronization

27. Flying squirrel experiment • Placed in total darkness, activity continued on a 24-hour cycle even without light • Biological clocks are internal mechanisms which keep the animal in sync with its environment, but external cues regulate the biological clock so that it fits a changing environment