Aspectos da história natural de aranhas-de-alçapão em duas unidades de conservação do Cerrado e Mata Atlântica do sudeste do Brasil.
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Data
2019-04-26
Autores
Trova, Everton Fernando
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Universidade Estadual Paulista (Unesp)
Resumo
Araneae é uma ordem bastante diversificada, sendo uma linhagem com grande sucesso evolutivo. A infraordem Mygalomorphae representa uma pequena porção da ordem Araneae e são animais sedentários que passam grande parte do dia em refúgios climaticamente estáveis. As aranhas-de-alçapão passam toda a vida ou parte dela dentro de uma toca revestida com seda e dotada de um opérculo. Local onde realizam todas as necessidades, caçam por emboscada, se alimentam, se reproduzem e realizam ecdise. Este trabalho teve como objetivo esclarecer alguns aspectos sobre a história natural das aranhas-de-alçapão e avaliar o perfil térmico e umidade nas áreas estudadas. Os resutados foram divididos em dois capítulos: I. A morfologia da toca e opérculo foram descritos, bem como a presença de ornamentos e o comportamento de defesa quando perturbadas em suas tocas. As variáveis morfológicas foram correlacionadas com o diâmetro da toca em questão. As áreas em que as aranhas-de-alçapão ocorrem apresentaram diferenças na vegetação. As tocas sendo os principais locais em que as aranhas passam parte da vida, em conjunto com a vegetação oferecem micro-habitats adequados e permite que as aranhas vivam por vários anos sem a necessidade de emigrar. A permanência no interior da toca evita contato direto com o meio externo reduzindo riscos de predação e com grandes variações climáticas podendo leva-las a morte. II. As áreas com a presença de aranhas-de-alçapão tiveram diferenças significativas com as áreas com ausência, quanto a temperatura e umidade. Áreas com presença foram mais úmidas e apresentaram um padrão de temperatura vertical (gradiente térmico) no solo. O gradiente térmico encontrado na área com presença e a umidade são caraterísticas que permitem as aranhas manter a temperatura e umidade corporal em equilíbrio evitando assim estress térmico e hídrico.
Araneae is a very diverse order, being a lineage with great evolutionary success. The Mygalomorphae infraorder represents a small portion of the Araneae order and are sedentary animals that spends much of the day in climatically stable refuges. Trapdoor spiders spend all or part of their lives in a burrow lined with silk and closed with an trapdoor. The place where they carry out all their needs, they hunt by ambush, feed, reproduce and perform ecdysis. This work aimed to clarify some aspects of the natural history of trapdoor spiders and evaluate the thermal profile and moisture in the areas studied. The results were divided into two chapters: I. The morphology of the burrow and trapdoor were described, as well as the presence of ornaments and the defense behavior when disturbed in its burrows. The morphological variables were also correlated with the diameter of the burrow in question. The areas in which trapdoor spiders occur showed differences in vegetation. The barrows being the main places of their lives, together with the vegetation provide suitable microhabitats and allows spiders to live for several years without the need to migrate. The stay inside the burrow avoids direct contact with the external environment reducing risks of predation and with great climatic variation that can lead to death. II. The areas with trapdoor spiders had significant differences with the areas with no trapdoor spiders in terms of temperature and humidity. Areas with presences were more humid and presented pattern vertical temperature (thermal gradient) in the ground. The thermal gradient found in the area with presence and moisture are characteristics that allow the spider to maintain the temperature and body humidity in balance thus avoiding thermal and water stress.
Araneae is a very diverse order, being a lineage with great evolutionary success. The Mygalomorphae infraorder represents a small portion of the Araneae order and are sedentary animals that spends much of the day in climatically stable refuges. Trapdoor spiders spend all or part of their lives in a burrow lined with silk and closed with an trapdoor. The place where they carry out all their needs, they hunt by ambush, feed, reproduce and perform ecdysis. This work aimed to clarify some aspects of the natural history of trapdoor spiders and evaluate the thermal profile and moisture in the areas studied. The results were divided into two chapters: I. The morphology of the burrow and trapdoor were described, as well as the presence of ornaments and the defense behavior when disturbed in its burrows. The morphological variables were also correlated with the diameter of the burrow in question. The areas in which trapdoor spiders occur showed differences in vegetation. The barrows being the main places of their lives, together with the vegetation provide suitable microhabitats and allows spiders to live for several years without the need to migrate. The stay inside the burrow avoids direct contact with the external environment reducing risks of predation and with great climatic variation that can lead to death. II. The areas with trapdoor spiders had significant differences with the areas with no trapdoor spiders in terms of temperature and humidity. Areas with presences were more humid and presented pattern vertical temperature (thermal gradient) in the ground. The thermal gradient found in the area with presence and moisture are characteristics that allow the spider to maintain the temperature and body humidity in balance thus avoiding thermal and water stress.
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Palavras-chave
Aracnologia, Araneae, Aranha-de-alçapão, Mygalomorphae, Caranguejeira, Natural history, Trapdoor spider, Tarântula