Zool 4312/5312: Animal Behavior Aug 28, 2012: Introduction

1. Zool 4312/5312: Animal Behavior Aug 28, 2012: Introduction Kenneth A Schmidt Texas Tech University Dept Biological Sciences

3. WHERE ARE the CHIPMUNKS ??

4. Methods ) ) ) ) ) ) ) ) ) • 16 Playback • 16 Control • (silent, frog) 17.6 m 42.1 m

5. Birds nested ~20m further away, on average, from chipmunk stations Distance to playback (m) Chipmunk Control Veery Ovenbird • Nesting passerines use information in chipmunk vocalizations to • avoid perceived hotspots of chipmunk activity

6. Soutpansberg Mountains, Limpopo Province, South Africa

9. Why does the Veery sing? Tinbergen’s 4 Why’s and causation in animal behavior “Why does the animal do that?” (1) In terms of the function or adaptive value – they sing to attract mates for breeding

10. Why does the Veery sing? in other words, we can substitute... “How is (or might) the behavior (be) adaptive?” Without implying that the animal is aware of its effects or actions - evolution produces machines that successfully reproduce themselves

11. (2) In terms of the Causation – the processes inside (endogenous) or outside (exogenous) that produces the observed behavior. They sing b/c increasing day length triggers hormonal changes in the body or b/c of the way air flows across the syrinx and creates membrane vibrations... (3) In terms of Development – they sing b/c they learned the song from parents or neighbors (4) In terms of the Evolutionary origins of the behavior – the evolution of complex songs arose from simpler songs of ancestral thrushes. All answers are right and it is pointless to argue about which is correct, rather it is important to distinguish between the different kinds of answers

12. ** Behavioral Ecology – defined as the attempt to predict behavior from 1st principles of evolutionary biology that consider the consequences of behavior on fitness (adaptive value) Ultimate Perspective/Causation Proximate Perspective/Causation Function or adaptive value • Proximate Causation • physiology • environmental control • Cognition – analyzing, using, • acquiring information – • e.g., day length Animal Behavior

13. Lions breed throughout the year, but females within a pride come into estrus • synchronously – • Prox: Chemical cues (pheromones) stimulate the beginning of estrus Ultim: Cubs born synchronously survive better: communal suckling of young; stronger male coalitions

14. Females come into heat for 2-4 days • over which 600+ copulations may occur • Prox: There is a high probability of • ovulation failure and abortion Ultim: Only 1:3000 copulations will produce a surviving cub & devalued copulations reduce the benefit of fighting for access to the female; increase paternity uncertainty to prevent males from killing young not fathered

15. After a pride takeover by new males, they will attempt to kill all the cubs • under ~18 mo. • Prox: Unfamiliar odor of cubs induces male to commit infanticide (Bruce Effect) Ultim: Induces females to come into estrus quickly; males do not invest valuable resources raising cubs which are not their own

16. Another example: Alternative male phenotypic strategies in tree lizards

17. Tree Lizard Urosaurus ornatus • 9 recognized color-morphs • 1 to 5 morph types per individual population • Fixed morph types with a genetic basis – in the lab, broods are a mix of • Orange and Orange-blue phenotypes in the same ratio as seen in the wild • Several behavioral correlates with dewlap color

18. 70 Orange-blue 60 Differences in aggressiveness of free-living males to a tethered random color morph male intruder 50 40 30 Orange 20 10 dewlap display approach face-off charge bite increasing aggressiveness

19. Orange Orange-blue • Small home range (20m2) • Nomadic during stressful times (e.g., drought) • Greater body mass; long and lean • Large ranges (85m2) • Sedentary, never nomadic • Smaller body mass, but more • massive at a given body length What do these represent ?

20. Orange Orange-blue • Small home range (20m2) • Nomadic during stressful times (e.g., drought) • Greater body mass; long and lean • Large ranges (85m2) • Sedentary, never nomadic • Smaller body mass, but more • massive at a given body length What do these represent ? Alternative Male Reproductive Strategies

21. A model for a hormonal mechanism of sexual differentiation male immature Fixed strategies female hormones immature nonbreeding Plastic responses breeding

22. Orange-blue territorial immature Fixed strategies sneaker hormones Orange Orange immature territorial Plastic responses nomadic

23. Progesterone determines male’s reproductive strategy • Progesterone levels evenly split between • 50% males 0.1-1 ng/ml • 50% males 10-100 ng/ml 100 75 (2) Male’s strategy is affected by progesterone injections at hatch day Percentage of males 50 25 control Progesterone (Moore 1998)

24. Aggressive and territorial; mate with all females in their territory Non-aggressive, mildly territorial in good yrs; mate by sneaking into territories to “steal” copulations

25. Summary: (1) Every question in Animal Behavior has a (actually several) proximal explanations that focus on the mechanisms of how the behavior and comes about; and one ultimate explanation based on function/adaptive value (2) Although we focused on hormones, hormones are linked to the environmental conditions, which provide a proximal stimulus, and they must have underlying genetic control – which itself is under molecular control ... (3) There is a tight fit between form (proximal mechanisms) and function (why has the trait evolved)