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lecture_notes:04-01-2015

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All About Banana Slugs April 1, 2015 **Guest Lecturers: John Pearse and Jan Leonard** **Slug Overview** **Habitat** Wide range of habitats: conifer forests, open woodlands, dry-land springs, coastal ice plants **Diet** Lab: lettuce, yams, hamburger, milk, cat food Field: mushrooms, plants, seem to prefer animal feces **Color** Different species have different colors, but colors are not species specific Not sure why they have their color **Predators** Garter snakes, birds No main predator in particular Their slime serves as a protection against predation **Distribution** Found along Pacific Coast line 5 major clades seem to have geographical specific ranges with little overlap Similar distribution as salamanders **Slug Taxonomy** mtDNA doesn’t separate our local Meadarion species, but they are known to differ based on social cues, egg size and morphology 2 subgenera based on penis morphology 1) Meadarion with epiphallus A.(A.) 2) Ariolomax with no epiphallus and thin-walled apical end of penis A.(M.) 5 clades in the genus: 2 within columbianus (A.(A.) columbianus and A.(A.) buttoni), A.(A.) stramineus, a 4th clade in San Diego County that is as of yet undescribed, and 5th clade (Meadarion) comprising of at least 4 subclades (A. (M.) californicus, A. (M.) brachyphallus, A.(M.) dolicophallus and a 4th undescribed species found in Fremont Peak) Further molecular taxonomy only performed with three genes CO1-16S-CytB **Slug Sex: The Basics** Simultaneous hermaphrodites; can’t distinguish sex until dissection Complex mating behavior with apophallation at times Copulate: internal fertilization, either simultaneous or alternating copulation Eggs are laid underground, take 1-2months to develop, requires humid envirnoment to protect from dessication Hatch as small individuals Same reproductive system as all terrestrial gastropods **Slug Sex Behavior: Apophallation** During copulation, penis of one and/or both slugs is bit off, this process is termed apophallation Penis does not regenerate, but slug continue its sex life as a "female" or "male" (incomplete apophallation) Does not occur until copulation has occurred for an extended period of time already Unknown if has effect on mating behavior/preference thereafter Apophallation rarely occurs (~5% observed by Jan Leonard), only seen in A. (M.) californicus and A. (M.) dolichophallus species in Meadarion subgenera Species differ in courtship and copulation behavior: A. (M.) californicus have longest courtship, A. (M.) dolicophallus have longest intromession, and A. (M.) bracyphallus display penile loop (distinguishing feature observed initially by Mead in 1943) Other phallus polymorphisms (developmental) are very common among gastropods and can associate with a certain environmental signal (eg. increased water temperatures) **Goal of Sequencing Project** Assemble and compare slug genomes to identify genes related to their rapid evolution of sexual phenotypes: Genital morphology Sexual behavior Pally polymoprhism Egg size Species recognition molecules Self-fertilization [[lecture_notes:04-01-2015:newest_page_test]]

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lecture_notes/04-01-2015.1428619581.txt.gz · Last modified: 2015/04/09 22:46 by thjmatthsoe