Defesas comportamentais de girinos de dendropsophus minutus (Hylidae) induzidas por aranhas-pescadoras (Thaumasia sp.: Pisauridae)

• Autor(a) principal: Mamede, Joyce de Lima
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/00130000049g6
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9542
• topic: Girino; Defesas induzidas; Aranha-pescadora; Dendropsophus; Thaumasia; Fishing spider; Induced defenses; Dendropsophus minutus; Thaumasia; Tadpole; CIENCIAS BIOLOGICAS::ECOLOGIA

Predator-prey interactions can cross ecosystem boundaries and the outcomes of these interactions are seen through the prey’s defensive behavior. However, when environmental conditions act as opposite selective pressure, behavioral defenses that maximize foraging as a function of predation risk are favored. In this context, our goal was to test how the presence of a semi-aquatic predator (Thaumasia sp.: Pisauridae) alters the behavior and foraging microhabitat of Dendropsophus minutus tadpoles in the presence and absence of conspecifics. Our hypotheses were that in the presence of the predator i) tadpoles were less active, ii) tadpoles foraged on the bottom, further from the predator, and iii) when conspecifics were present, tadpoles were more active and foraged evenly. Activity was measured as proportion of time moving and foraging microhabitat was measured by the total percentage of food removed, percentage of food removed on the top and percentage of food removed on the bottom of the aquarium (permutational ANCOVA). Activity and foraging microhabitat were dependent on tadpole's size. Larger tadpoles were less active, removed more food from the bottom and as a whole. The presence of the fishing-spider decreased tadpole's activity, but the presence of conspecifics didn't dilute the predator's effect. Tadpoles foraged more on the bottom when the fishing spider was present. The presence of a semi-aquatic predator induced defensive responses in tadpoles and the presence of conspecifics had an impact opposite to expectations. Tadpole's response was dependent on size, which might suggest that larger tadpoles are under stronger selective pressures. Our experiment show empirically that fear effects can be exported, generating cascades systems with different impacts on the recipient ecosystem.