Bio 3400 1nd Edition Lecture 29 Outline of Last Lecture I Competition II Niche differentiation III Character displacement IV Exploitative Interactions V Diet width VI Optimal foraging theory Outline of Current Lecture I Mutualisms II Benefits of mutualism III Balancing costs and benefits IV Hypotheses for preventing cheating Current Lecture I How do mutualisms evolve a For mutualism to evolve and persist the benefits must exceed the costs for both partners II Types of Benefits of Mutualisms a Nutrition b Protection cleaner and client fish client fish protected from parasites c Transportation pollen and pollinators seed dispersers sea anemone on crab shell III Plants and Mycorrhizal Fungi nutrients nutrients exchange a Fungi allows plants to uptake more nutrients help extends the roots surface area b Plants i Can be obligate or facultative ii Improve uptake of phosphorus nitrogen and water c Mycorrhizae i Can be obligate or facultative ii Constant source of carbohydrates IV Ants and Acacias Nutrients protection exchange a Ants i Obligate mutualism ii Live and reproduce in thorns iii Feed at nectaries and on Beltian bodies b Acacias 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 V VI VII i Facultative mutualism ii Protection form herbivores if you swipe up against the tree all these ants will come swarming out iii Grow faster with ants iv Increased survival with ants Plants and Pollinators Nutrients transportation exchange a Figs and fig wasps 300 species b Fig wasp i Obligate mutualism ii Females lay eggs in fig flowers iii Wasps develop inside the fig c Fig i Obligate mutualism ii Pollination iii Number of pollinated flowers number of seeds produced Balancing costs and benefits a What are the benefits and costs for the fig i Benefits pollinated ii Costs the flowers that are habited by wasps are unable to be pollinated iii If there is variation in the number of flowers wasps oviposit in to produce offspring would you expect natural selection on wasps to favor high or lower levels of oviposition 1 Best for the wasp higher levels of oviposition higher reproduction what keeps this in check we don t know b Cheaters i Cheaters benefit but pay lower costs 1 Cheaters by mutualist partners 2 Cheating from other species other species of wasps try to oviposit the figs flower with no nectar being pollinated but not benefiting the pollinators Hypothesis for preventing cheating a Partner fidelity i Close repeated interactions ii Negative effects on partner 2 feedback to negatively affect partner 1 b Partner choice i Compare quality of partners and choose best ii E g Yucca plants can selectively abort fruits with too many yucca moth caterpillars Client fish switch cleaners c Cheater defenses i Adaptations to protect against cheating ii E g long or thickened corollas to prevent nectar robbing iii coevolutionary arms race
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