102, NPB Animal Behavior Winter 2011 Study Questions for Chapter 7 1. What is a search image? What advantages (benefits) do search images confer, and what potential disadvantages (costs)? Describe experimental evidence illustrating these advantages and disadvantages. 2. What happens when Portia spiders are first primed with exposure to a preferred prey item and then presented with either the same or different prey in (a) a test situation where the prey is freely visible, and (b) a test situation where the prey is partially concealed? What does this result reveal about the role of search images in foraging behavior? 3. Explain whether you think it is more useful to quantify detection or consumption when evaluating whether or not a search image is present. 4. What is frequency-dependent selection, and how can it account for the coexistence of alternate foraging phenotypes? Provide at least one specific example. 5. What is the difference between a strategy and a tactic? Give an example where (a) a single tactic defines a strategy, and (b) a strategy involves multiple tactics. 6. Describe the behavior of ruddy turnstones foraging on sandy beaches with specific reference to the different tactics that individuals use. Is each of these tactics what you would call a distinct strategy or just a separate tactic of a single conditional strategy? Explain your reasoning. 7. What would you need to know in order to determine whether fish stealing behavior by roseate terns is a tactic of a conditional strategy or a fixed strategy? 8. Explain how optimality models have been used to better-understand how crows foraging on whelks choose and handle prey. How have those models been finetuned using empirical data? 9. What are the round dance and the waggle dance performed by honeybees, and how are they thought to facilitate efficient foraging? Describe an experimental manipulation the results of which are consistent with this idea. 10. When we study the ultimate causes of variation in behavior we need to assess fitness in some way. Ideally, we should assess fitness directly. What do we need to measure if we want to assess fitness directly? In practice, it is not always practical to measure fitness directly, in which case we may instead use fitness proxies. What is a fitness proxy? What are some specific examples of fitness proxies? (Hint: Think about assumptions underlying optimal foraging theory.) What are some advantages and disadvantages of using fitness proxies instead of directly measuring fitness? Can you think of any advantages to measuring fitness directly and also measuring some fitness proxies at the same time? 11. What does it mean to say that behavior of individuals can affect at patterns higher levels of organization? How does work on oystercatchers and highintertidal limpets illustrate this idea? 12. What is intertidal zonation and what kinds of factors are thought to be responsible for it?
13. What is the difference between absolute and relative intertidal height? Why might it be important to use relative height rather than absolute height when considering the distribution of organisms? Describe a specific example discussed in class that illustrates how considering relative height helps to reveal whether limpet distribution in a particular location is more likely to be caused by predation or by physical factors. 14. What are some key ways in which behavior of Lottia digitalis and Maclintockia scabra differ? 15. Use an optimal foraging kind of argument to discuss the factors affecting oystercatchers preferences for some limpets over others. In composing your answer you should think about a number of different factors, such as energy required to obtain the prey, energy gained from consuming the prey, time involved in locating the prey, time involved in handling the prey once found and attacked, efficiency with which prey is processed in the gut, etc. 16. Oystercatchers tend to eat very few Maclintockia scabra on granite substrata at Pacific Grove, and to eat large numbers of Lottia digitalis and other limpets there despite the fact that those limpets are much less prevalent than scabra in areas accessible to the birds. However, oystercatchers are relatively uncommon there, so the magnitude of the predation pressure is relatively low. Use an optimal foraging argument to predict what would happen to oystercatcher prey selectivity, as well as to limpet distribution and abundance, if the density of foraging oystercatchers were to increase dramatically around Pacific Grove. 17. Some rock types (e.g., greenstone, such as is prevalent in some parts of the Big Sur coast of central California) are extremely smooth and very hard too smooth to provide physical structure for the shell to interact with and too hard for scabra to etch home scars into them. Based on what you know of oystercatcher prey preference and limpet distribution on granite and sandstone, and of limpet behavior on these different types of rocks, how would you expect oystercatcher prey selectivity and limpet distribution and abundance to differ on smooth hard rocks like greenstone from what has been observed on granite and sandstone shores? Explain your reasoning, and include a discussion of what limpet species and sizes you would expect to be in the oystercatchers diets, and where you would expect to find limpets of different species and sizes living in this type of area.