Abstract Detail

Recent Topics Posters

Santos, Wagner Luiz [1], Pôrto, Katia Cavalcanti [2], Bordin , Juçara [3], Pinheiro , Fábio [4].

Density dependence of male sexual expression in metapopulations of a tropical moss: a monoicous species that is almost dioicous.

Reproductive traits such as reproductive allocation, sexual expression, sex ratio, and reproductive success, are central aspects of a species' ecology and evolution. For example, biases in male and female sex expression may play a large role in determining the viability of populations in the face of environmental pressures such as population fragmentation, climate change and habitat occupancy. Thus, in this study, we investigated reproductive traits in 10 metapopulations of the rhizautoicous moss Fissidens flaccidus Mitt. Rhizautoicous species have compartmentalization of sexual functions (functionally dioicous). We investigated the following questions: (1) is male reproductive allocation greater than female?; (2) is there a trade-off between sexual and asexual reproduction?; (3) is the number of male ramets a determinant for greater reproductive success?, and (4) is population density related to the sexual expression of ramets? From each metapopulation, 30 patches were randomly selected, and samples were collected from each patch of 1cm2. A total of 20173 ramets were analyzed and classified into male (ramet with perigonia), non-sporophytic female (ramet with perichaetia), sporophytic female (ramet with sporophyte), and non-sex expressing (ramet without sexual expression). From these sets of ramets, we randomly selected 50 ramets of each category (male, non-sporophytic female, sporophytic female, and non-sex expressing). We counted the gemmae production of each ramet, and for ramets that have sexual expression, we separated male and female gametoecia (respectively perigonia and perichaetia), and sporophytes. Then, ramets and reproductive structures were weighed to quantify reproductive allocation. In addition, population density in each patch was quantified. Our results showed that relative reproductive allocation in perigonia and sporophytes is greater than perichaetia. In addition, a trade-off between sexual relative reproductive allocation and asexual gemma production was observed, suggesting an important role of female ramets in asexual reproduction. The number of male ramets does not influence the reproductive success observed in each patch, and ramet density may induce male sex expression. Thus, we concluded that reproductive allocation in male function is efficient, since fewer male ramets can assure a considerable reproductive success. Furthermore, our results suggest that there may be a habitat preference between the sexes, since male ramets are found in patches with high density and mostly below female ramets, suggesting an avoidance of direct sunlight by male ramets.

1 - Alaor Ventura, 47, Itaú De Minas , MG, 37975000, Brazil
2 - University of Campinas, Plant Biology, R. Monteiro Lobato, 255 - Barão Geraldo, Campinas, São Paulo, 13083-862, BR
3 - Universidade Estadual do Rio grande do Sul
4 - University of Campinas, Plant Biology, R. Monteiro Lobato, 255 - Barão

life history
Resource allocation
Reproductive Success

Presentation Type: Recent Topics Poster
Number: PRT010
Abstract ID:1239
Candidate for Awards:None

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