Abstract
Males of Iporangaia pustulosa (Arachnida: Opiliones) have a sexually dimorphic metatarsus IV, which is thicker and with more glandular pores in males. Here we tested the hypothesis that this glandular area is used by males to leave chemicals in the environment, predicting that the animals would rub the metatarsus IV against the substrate. We have made recordings both in the field and in the laboratory, in several distinct contexts during the day and at night, comprising 67 hours of observations. We also experimentally tested the reaction of both sexes to a filter paper rubbed on the metatarsus gland, with adequate controls. We report and describe for the first time that the metatarsal gland of I. pustulosa is used to leave chemicals on the substrate by rubbing or touching it against the substrate. We also provide evidence that males can control the release of secretions of the metatarsal gland IV.
Acknowledgements
We thank all the members of LESCA (Laboratory of Sensory Ecology and Behavior of Arthropods) for carefully revising the manuscript: Guilherme Gainett, Guilherme Pagoti, Jessica Dias, Júlio Segovia, Norton Silva-Santos and Thaiany Costa. Julio Segovia, Guilherme Gainett, Norton Silva-Santos and Faustino Avelino Ribeiro also helped in the field. Júlio Segovia also helped with the laboratory experiments. We also thank Afonso Pelli for kindly letting us use laboratory space. Gustavo Requena and Kleber Del-Claro are thanked for the useful suggestions and discussions that helped to improve the manuscript.