Cothran, Rickey

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Southwestern Oklahoma State UniversitySWOSU Digital CommonsFaculty Articles & Research Biological Sciences10-30-2015Sexual selection in an ecological context: Insightsfrom amphipodsRickey CothranSouthwestern Oklahoma State University, rickey.cothran@swosu.eduFollow this and additional works at: https://dc.swosu.edu/cas_biology_articlesThis Article is brought to you for free and open access by the Biological Sciences at SWOSU Digital Commons. It has been accepted for inclusion inFaculty Articles & Research by an authorized administrator of SWOSU Digital Commons. An ADA compliant document is available upon request. Formore information, please contact phillip.fitzsimmons@swosu.edu.Recommended CitationCothran, Rickey, "Sexual selection in an ecological context: Insights from amphipods" (2015). Faculty Articles & Research. 2.https://dc.swosu.edu/cas_biology_articles/2Sexual selection in an ecological context: Insights from amphipodsRickey D. CothranSouthwestern Oklahoma State UniversityDepartment of Biological SciencesIntrasexual selectionIntersexual selectionpaddleSexual conflictWhy does understanding the mechanism of sexual selection matter?Population-level consequences ofsexual selectionfemale choicefemale fitnessmale traitssexual conflictfemale fitnessmale traitsHow might the ecological context affect sexual selection?The environment can affect costs andbenefits of matingphoto by Christian ZieglerThe environment can affect development of mating traitsgenes Interaction environmentdevelopmentantlersHumans are rapidly changing the environment: Consequences for sexual selection?Amphipod natural history & ecologyHyalella amphipodsAmphipod mating biologyMating biology tightly linked to the female molt cycleD0D8D6D3D10D10Consequences of time-limited female receptivityPrecopulatory mate guardingPatterns of selection in thefieldPairing Success1.00.80.60.40.20.0Trait0.3 0.42 0.810.680.55Patterns of selection in the field0.14 0.25 0.590.480.37Patterns of selection in the fieldWhich mechanism(s) of sexual selection are important?Is there sexual conflict in Hyalella populations? Identifying sexual conflictshared mating trait+malefitnessfemalefitnessIdentifying sexual conflictmaleoffensetraits+malefitness++Mating rate-- femalefitnessIdentifying sexual conflictfemaledefensetraits--Mating rate+malefitness+- femalefitnessWhat shared mating trait might the sexes disagree about in Hyalella amphipods?shared mating traitmale fitnessfemale fitnessfemale defense traits- -+Do the sexes disagree over pairing durati n?male offense traits +Hypothesis: Disabling a defense/offense trait should shift the shared mating trait in favor of the opposite sex.Experiment 1: Does reducing femaleresistance increase pairing duration?maleoffensetraits+X femaleresistancebehavior-Experiment 1: Does reducing femaleresistance increase pairing duration?Pairing duration (h)8 06 04 0200Control Sedated50% increaseExperiment 2: Does removing male claws decrease pairing duration?X male claws +femaleresistancebehavior-gnathopod (aka claw)pereopod (aka walking leg)Experiment 2: Does removing maleclaws decrease pairing duration?Pairing duration (h)806040200Intact Walking leg ClawAppendage removed80% decreaseThe sexes disagree, but do females paya cost for losing the conflict?+malefitness- femalefitnessHypothesis: Spending more time paired will decrease female fitness.Does pairing increase predation risk?+ size selective pairs > males > females- size selectivemales > females > pairsExperiment 1: Do bluegill sunfishprefer to  eat pairs?Consumed (% of trials)6040200Females Males PairsExperiment 2: Do larval dragonflies prefer to  eat single individuals?Consumed (% of trials)6040200Single Paired FemalesSingle Paired Malesmale traitsfemale fitnesssexual conflictmale traitsfemale fitness?In habitats without fish, do females benefit from mating with successful males?Do choosy females get direct benefits while paired?Does pairing with a larger male decrease a female’s predation risk?Probablity female captured1.00.80.60.40.20.0Male size (head length mm)0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85Mate guarding is a common strategy in nature!Do choosy females get indirect benefits?Testing for indirect benefitsResponse variablesSurvivalJuvenile growth rate Daughters’ fecundity Sons’ mating successChoice treatmentsoriginalvs.randomDo choosy females produce sexiersons?Number of families121086420Duds Avg. Joes StudsRandomChoicemale traitsfemale fitnessfemale choiceWhat we are working on now…..Question 1: Do we see coevolutionary patterns between male offense traits and female defense traits in nature?W hat we are working on now.....ln(Claw size mm)ln(Body size mm)Can the environment affect development of mating traits?genes Interaction environmentdevelopmenttraitIs the development of sexually selected traits particularly sensitive to stress (i.e. highly condition dependent)?Warren et al.  2013, BioessaysThe paradigmThe problems1) No control traits2) Not accounting for changes in body size across resource environments3) Extreme or unnatural resource environmentsCotton et al.  2004, Proc. Roy. Soc. BHypothesis: Sexually selected traits will be more sensitive to changes in resource availability than non-sexual traits.No control traits1 mm500 µmMaleFemalePG AGPAPGPAPGAGPAPGAGPAUsing unrealistic resource environmentsAre sexual traits more sensitive tophosphorus availability?Phosphorus sensitivityWalkinglegSmallclawAntenna LargeclawImplications for sexual selectionLowphosphorusfrequencyclaw sizeHighphosphorusclaw sizeSexual conflict - females have more well-armed males todeal withFemale choice - females have less variation to choose fromW hat we are working on now.....Does natural and human-caused variation in P availability affect sexual selection in nature?What we are working on now…..Leaf litter varies in nutrients!Does the type of leaf litter affect sexual trait development?Claw size (mm)0.450.400.350.300.25Elm BlackW illowBlackCherryAspenDoes the type of leaf litter affect sexual trait development?Antenna size (mm)0.360.340.320.300.280.26Elm BlackW illowBlackCherryAspenWhat about human-caused variation in P-availability? Take home message• The ecological context clearly affects how sexual selection operates in populations.• To understand the consequences of rapid human-induced environmental change we need to explore how evolutionarily labile traits (e.g., sexually selected traits) respond to environmental change and the consequences of these responses.Thanks!G ary W ellborn  Univ. of Oklahoma Rick Relyea RPIPuni Jeyasingh Oklahoma State Univ. Aaron Sto ler RPIJessica Hua Univ. of BinghamtonHigh School Teachers Ray G reco Knoch High School Kris Chapman Greenville High School Cindy M urray Northwestern High SchoolStudentsForrest Radarian High School Teacher Jenise BrownGrad Student Univ. of South FloridaAndy StiffMedical School at Ohio StateKate HendersonGrad Student Montana State Dave Schm idenberg (Environmental Consultant) Patrick NoyesGrad Student Univ. of Maryland Beverly French Grad Student UCSB Pat Monahan ESAAshna Dhoonm oon, Sinthia Youmbi, Lindsey Hendricks, Shanna Simmons, and Lau Nguyen(students at SW O SU )Figure 3. Species of Nymphalidae from the Yucatan Peninsula showing deep sequence divergence (&gt;2%) at COI. Prado BR, Pozo C, Valdez-Moreno M, Hebert PDN (2011) Beyond the Colours: Discovering Hidden Diversity in the Nymphalidae of the Yucatan Peninsula in Mexico through DNA Barcoding. PLoS ONE 6(11): e27776. doi:10.1371/journal.pone.0027776 http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027776 Prado et al. 2011, PLOS Mechanisms that maintain species diversity in communitiesFortunately, they are not as cryptic when aliveSpecies A Species B Species CEvo-ecotoxicologymale traitsfemale fitnessmale traitsfemale fitnessHypothesis: Males with large sexual traits will still be successful when we remove the opportunity for male-male competition.  Large maleSmall maleExperiment 1: Does tethering affect the success of large males?Experiment I : Does tethering affectthe success of large males?Cases larger male paired (%)100806040200Free TetheredExperiment I : Does tethering affectthe success of large males?Cases larger male paired (%)Free TetheredExperiment I : Does tethering affectthe success of large males?Cases larger male paired (%)Free TetheredMale AMale BThe arenahappy malelonely maleFocal maleCompetitorDoes tethering affect the success of males with large claws?% * .gnathopod (aka claw)pereopod (aka walking leg)Does tethering affect the success ofmales with large claws?Focal male paired (%)Appendage removedDoes tethering affect the success ofmales with large claws?Focal male paired (%)Appendage removedDoes tethering affect the success ofmales with large claws?Focal male paired (%)Appendage removedFly fisherman’s amphipodTrait variation (%AD)DensityTrait variation (%AD)Densitylow density high density1 mm500 µmMaleFemalePG AGPAPGPAPGAGPAPGAGPAresourcessexual traitnon-sexual traitnon-sexual traitconditionmating successfecunditysurvival-+

Sexual selection in an ecological context: Insights from amphipods

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Sexual selection in an ecological context: Insights from amphipods

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