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Population dynamics and habitat selection of Selenops cocheleti Simon, 1880 (Araneae: Selenopidae) in the Serra do Japi, São Paulo, Brazil

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Author(s):
German Antonio Villanueva Bonilla
Total Authors: 1
Document type: Master's Dissertation
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
Defense date:
Examining board members:
João Vasconcellos Neto; Vanessa Stefani Sul Moreira; Martin Francisco Pareja
Advisor: João Vasconcellos Neto
Abstract

Population studies on spiders indicate that food availability, habitat complexity and climatic variables are the most important factors in fluctuation in the number of individuals within the population. Selenops cocheleti Simon, 1880 (Araneae: Selenopidae) belongs to family of nocturnal wandering spiders that, due to its flattened ventrally, usually they occur on trunks of trees, underneath rocks or shells. However, due to their fast movements, their ability to hide in inaccessible places and the fact that they are nocturnal, it makes the knowledge that we have about the natural history of them still incipient. Because individuals of S. cocheleti are often observed on tree trunks, the main objectives of this work were: (1) describe population fluctuation, phenology and diet of Selenops cocheleti on trunks of Plinia cauliflora and Pinus elliottii; (2) study the preferences of S. cocheleti by specific plants with specific morphologies. The population of S. cocheleti was registered monthly in conjunction with climatic variables such as temperature and precipitation in addition to the available prey on the study area. Subsequently, we made analyses of relationship between climatic variables and prey abundance with the abundance of S. cocheleti. To determine the availability of tree species used for selenopídeos, we used the data collected in 2007 where 15 plots 10x30m were made, being registered: number of tree species, DAP, characteristics of the trunk (loose bark, cracks). Were also estimated densities of S. cocheleti in 40 individuals of Pinus elliottii, Eucalyptus grandis, Plinia cauliflora, Piptadenia gonoacantha, Croton floribundus and native trees that have different characteristics on the trunk. Finally, an experiment was carried out in the field where shelters of different materials (plywood, metal, shell) were placed in smooth and rough trunks (n = 40) to test whether S. cocheleti showed preferences for one type of stem (smooth or rough) and preference for a specific type of shelter. As a result, adult females¿ longevity and his ability to keep the sperm from the male for a long period of time determine the structure of the population by placing egg-sacs continuously during the year, thus having permanent recruitment of individuals. The present study also recorded that S. cocheleti is strongly associated with plants that have scaly stems and smooth texture on the trunk. These preferences of the spiders by habitat are due to use of the cracks as a shelter that is formed between the loose bark and trunk. Our study also suggests that there is a preference for S. cocheleti by plants of the family Myrtaceae in comparison with other plants available. This preference for plants Myrtaceae is not exclusive because of registration of theses spiders in tree trunks of other native (Piptadenia gonoacantha) and non-native species (Pinus elliottii, Eucalyptus grandis) in Brazil (AU)

FAPESP's process: 13/16469-8 - Population dynamics and association of Selenops cocheleti Simon, 1880 (Araneae: Selenopidae) with plants of family Myrtaceae in the Serra do Japi, São Paulo, Brasil
Grantee:German Antonio Villanueva Bonilla
Support Opportunities: Scholarships in Brazil - Master