6th Edition WFSC 403 Lecture 17 Outline of Last Lecture I Lab Studies a Essay page 197 II Field Studies a Essay page 197 III The Big Question a The Answer IV The Approach a Predator responses to changes in prey density V Evolution of predator prey systems Outline of Current Lecture I Remaining details a Chapter 11 II Predation responses to change in predator density a Switching b Optimal foraging theory i Chapter 3 page 36 III Evolution of predator prey systems a Prelude to Disease chapter b Predators take the weak Current Lecture Predator responses to change in prey density o Functional response As prey density increases the per capita predation rate increases Be able to identify the three types These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Type one prey just coming by and being eaten Jelly fish tentacles reaching out and just putting in to mouth parts Type two is the fixed handling time or digestive pause Type three As the prey population gets lower and lower the predator switches to different prey Switching o Search image More toned in to specific prey But as the prey decreases switches to a different prey When down at relatively low prey densities a relative the predators are consuming less then the prey When the prey increases to relatively high populations the predator switches to eating that Switches search image prey as the populations change o Numerical response Prey numbers increase predator numbers increase Prey numbers decrease predator decrease Onsite reproduction o Aggregative response Aggregation of predation in an area Emigration of predators decreases prey density Type of numerical response o Developmental response Predator prey on different prey depending on their developmental stage larvae Optimal foraging theory o Should I eat this or eat this o Two different species that potentially have different digestively and how much energy it is to catch them vs how much energy that will be gained o How hard to catch Energy value What type of functional response is this o Type two lynx and snow shoe hare Dotted line is line where anything above is surplus killing The lynx will not switch prey o May come in change in per capita predators Sticky tongued frog slippery footed fly o What limits sticky tongue and slippery foot Fly can t land on plant or something frog gets stuck to other things Prelude to disease o Worried about resistance Predators take the weak Increase vigor of the prey o Do they always take the weak Prey density higher prey density going to take the easiest one If good at catching prey it doesn t matter whether take weak or easy Take weak under certain conditions but not all conditions Return to big picture o Summary pg 207 o Stabilize when several species evolve prey have hiding habitat predators take prey of little reproductive value Additive compensatory Switching Predator switch prey Predator preying on set of prey species certain biodiversity prey Relative abundance take predator away biodiversity of prey decreases when predator taken away o Predator holding prey at relatively low density o Predator taken away the prey increases and competitive exclusion
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