16&17_local adaptation '09

16&17_local adaptation '09 - Worm grunting causes...

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1 In southern U.S., Diplocardia mississippiensis earthworms are sought after by fisherman. Bait-sellers have an interesting way of collecting the worms, called worm grunting , or (in U.K., worm charming). Worm grunting causes worms to emerge from the ground where they are collected and sold. Ken Catania wondered if grunting mimicked sounds of moles, which prey on worms. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0003472 eastern American mole Worm grunting mimics mole sounds. Same response to playbacks. In Europe herring gulls and wood turtles engage In Europe, herring gulls and wood turtles engage in worm grunting, and feed on worms as they emerge! Convergent evolution? Maybe. Evolution involves genetic changes in populations. Can we see differences within a species due to natural selection? Gulls or Turtles Present? Moles Present? Predicted Response of Worms to Vibrations Yes No Weak No Strong
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2 roportion Genotypes of Type A What We Would Like to See 1 Suppose a mixture of genotypes in a population, of which one is ‘Type A’. What happens to the frequency of Type A when Environment Evolutionary Time P 0 Documented examples of such change •industrial melanism in Biston betularia pepper moths •pesticide resistance in insects •antibiotic resistance in pathogens environment changes to favor A changes to favor it? # generations Proportion Genotypes 1 0 Maybe the next best thing? Examine different populations in which one might NOW Population 1 Env. changes to favor A which one might expect selection to differ. See if behavior is, in fact, locally adapted. #generations Env. changes to favor B 1 0 Population 2 Three criteria for Three criteria for local adaptation: local adaptation: 1. Geographic variation in a trait 2. Variation at least partly genetically-based 3. Genetic variation in the trait consistent with geographic variation in some environmental factor affecting fitness Case Study #1: Local Case Study #1: Local Adaptation in Feeding Adaptation in Feeding Preference in the Spider, Agelenopsis Agelenopsis aperta aperta funnel web spider ’ common in American Southwest. female w/ eggs builds funnel webs, opening out onto silken platform. The spider sits at funnel entrance, running out when insects fall onto platform. Site Habitat Proportion Attacked Attack Latency (sec) Reichert and Hedrick found that spiders in Arizona populations attack less vigorously than spider populations in New Mexico. Arizona Riparian 0.25 55.0 (0.3) New Mexico Grassland 0.90 2.6 (0.3) CRITERION 1 MET!
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3 Criterion 2 (differences genetically-based) can be tested with ‘common garden’ experiment’. Arizona riparian spiders N.M. grassland spiders common environment Any differences in F 1 and later generations are probably genetic differences.
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This note was uploaded on 12/09/2009 for the course ECOL 487R taught by Professor Papaj during the Spring '09 term at University of Arizona- Tucson.

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16&17_local adaptation '09 - Worm grunting causes...

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