In mating systems with resource defense, resource distribution has influence over female distribution and thus on various behavioral and population parameters. The main objective of this project is to evaluate the effect of the availability of egg-laying sites on the mating system and parental care of the harvestman Serracutisoma proximum. Males of this species defend territories over the vegetation at river margins where the females lay eggs. There is also a alternative male morph, of reduced body size, that instead of fighting for territory ownership, invade the harems to perform sneak copulations. In the first chapter we will investigate how the reduction of egg-laying site availability influences behaviors strictly related to the mating system. In areas with lower resource availability we expect: (a) more agonistic interactions among males; (b) higher substitution rates of territorial residents; (c) higher average body size of the territorial residents; (d) larger harem size; (e) increased locomotion of sneaker males; (f) higher promiscuity of females. In addition to testing these strictly behavioral previsions, in the second chapter we will combine complex network theory and mating systems theory, to investigate how social interaction patterns vary under conditions of high and low availability of egg-laying sites. Finally, in the third chapter, we will perform an experiment to test how variations in the availability of egg-laying sites influences the tendency of males to perform temporary parental care. We hypothesize that territorial males will be less prone to care for the offspring on the areas of lower resource availability, for with larger harems each territorial male will possess a higher number of clutches, lowering the individual value of each one. Another possible explanation is that with higher female promiscuity, paternity certainty will be diminished, and the costs of male parental care will be higher. We will perform the field work at Intervales State Park, and the data will bring new information about: (a) the effect of resource availability on the mating system of an arthropod species; (b) the sexual interaction network in a context of alternative mating strategies; (c) the evolution of paternal care in harvestmen.
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