Conditional male dimorphism and alternative reproductive tactics in a Neotropical arachnid (Opiliones)

Autor(es)

Buzatto, Bruno A. ^[1] ; Requena, Gustavo S. ^[2] ; Lourenco, Rafael S. ^[3] ; Munguia-Steyer, Roberto ^[4] ; Machado, Glauco ^[4]

Afiliação do(s) autor(es)

^[1] Univ Western Australia, Sch Anim Biol G 09, Ctr Evolutionary Biol, Crawley, WA 6009 - Australia

^[2] Univ Sao Paulo, Inst Biociencias, Programa Posgrad Ecol, BR-05422970 Sao Paulo - Brazil

^[3] Univ Estadual Campinas, Inst Matemat & Estat, Dept Estat, Campinas, SP - Brazil

^[4] Univ Sao Paulo, Inst Biociencias, Dept Ecol, BR-05422970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: EVOLUTIONARY ECOLOGY; v. 25, n. 2, p. 331-349, MAR 2011.
• Citações Web of Science: 39

Resumo

In arthropods, most cases of morphological dimorphism within males are the result of a conditional evolutionarily stable strategy (ESS) with status-dependent tactics. In conditionally male-dimorphic species, the status' distributions of male morphs often overlap, and the environmentally cued threshold model (ET) states that the degree of overlap depends on the genetic variation in the distribution of the switchpoints that determine which morph is expressed in each value of status. Here we describe male dimorphism and alternative mating behaviors in the harvestman Serracutisoma proximum. Majors express elongated second legs and use them in territorial fights; minors possess short second legs and do not fight, but rather sneak into majors' territories and copulate with egg-guarding females. The static allometry of second legs reveals that major phenotype expression depends on body size (status), and that the switchpoint underlying the dimorphism presents a large amount of genetic variation in the population, which probably results from weak selective pressure on this trait. With a mark-recapture study, we show that major phenotype expression does not result in survival costs, which is consistent with our hypothesis that there is weak selection on the switchpoint. Finally, we demonstrate that switchpoint is independent of status distribution. In conclusion, our data support the ET model prediction that the genetic correlation between status and switchpoint is low, allowing the status distribution to evolve or to fluctuate seasonally, without any effect on the position of the mean switchpoint. (AU)

• Processo FAPESP: 08/53737-2 - Evolução do dimorfismo sexual e intrassexual em opiliões da família Gonyleptidae (Arachnida: Opiliones): uma perspectiva ecológica e evolutiva
• Beneficiário: Roberto Edmundo Munguía Steyer
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 09/50031-4 - Evolucao do dimorfismo sexual e intrasexual em opilioes da familia gonyleptidae (arachnida: opiliones)
• Beneficiário: Glauco Machado
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 03/05427-0 - Custos e benefícios do cuidado maternal no opilião Serracutisoma proximum (Opiliones: Gonyleptidae)
• Beneficiário: Bruno Alves Buzatto
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 02/00381-0 - Investimento parental e evolução do comportamento sub-social em opiliões da família Gonyleptidae (Arachnida: Opiliones)
• Beneficiário: Glauco Machado
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 03/05418-1 - Cuidado paternal no opilião Iporangaia pustulosa (Opiliones: Gonyleptidae)
• Beneficiário: Gustavo Requena Santos
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica