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Abstract Detail

Reproductive Processes

Miller, Jill S. [1], Kamath, Ambika [2], Levin, Rachel Ann [1].

Floral size and shape evolution following the transition to gender dimorphism.

Floral morphology is expected to evolve following the transition from cosexuality to gender dimorphism in plants, as selection through male and female function becomes dissociated. Specifically, male-biased dimorphism in flower size can arise through selection for larger flowers through male function, selection for smaller flowers through female function, or both. The evolutionary pathway to floral dimorphism can be most effectively reconstructed in species with intraspecific variation in sexual system. We examined the evolution of flower size and shape in Lycium californicum, whose populations are either gender dimorphic with male and female plants, or cosexual with hermaphroditic plants. Floral morphology was characterized in populations spanning the species’ complete range. For a subset of the range where cosexual and dimorphic populations are in close proximity, we compared the size and shape of flowers from female and male plants in dimorphic populations to hermaphrodites in cosexual populations, accounting for variation associated with abiotic environmental conditions. The magnitude of flower size dimorphism varied across dimorphic populations. After controlling for environmental variation across cosexual and dimorphic populations, flowers on males were larger than flowers on females and hermaphrodites, whereas flower size did not differ between females and hermaphrodites. Flower shape differences were associated with mating type, sexual system, and environmental variation. While abiotic environmental gradients shape both overall flower size and shape, male-biased flower size dimorphism in L. californicum appears to arise through selection for larger flowers in males but not smaller flowers in females.

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1 - Amherst College, Department Of Biology, McGuire Life Sciences Building, Amherst, MA, 01002, USA
2 - Harvard University, Organismic and Evolutionary Biology, Cambridge, MA, 02138, USA

environmental gradients
floral evolution
gender dimorphism
male sterility
sexual dimorphism
Lycium californicum.

Presentation Type: Oral Paper
Session: 30, Reproductive Processes
Location: Fort Worth Ballroom 7/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 3:00 PM
Number: 30006
Abstract ID:156
Candidate for Awards:None

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