Keywords :
Predation; Feihyla hansenae; Hansen s Bush Frog; Web Spider
บทคัดย่อ :
Feihyla hansenae (Cochran, 1927) is an arboreal- breeding frog distributed in Thailand, Cambodia, and Myanmar (Taylor, 1962; Aowphol et al., 2013). Eggs are laid in a gelatinous hemispherical clutch overhanging ponds and are cared for by female frogs until they hatch (Average egg stage = 5 days). Maternal care, viz. suppling water (Poo & Bickford, 2013) and deterring invertebrate predators (Poo et al., 2016a), is essential to the development and survival of eggs. The primary source of egg mortality is predation (Poo & Bickford, 2013). Known egg predators include ants, katydids, and snakes (Poo & Bickford, 2013; Poo et al., 2016b). In cases of partial clutch predation, threats from egg predators can lead to premature hatching in F. hansenae (Poo & Bickford, 2014), which can negatively affect the fitness and survival of hatchlings in subsequent life stages (Gomez-Mestre & Warkentin, 2007). Here, we report the first observation of F. hansenae egg predation by a nursery web spider, Nilus cf. albocinctus (family Pisauridae, Fig. 1). Field observations were conducted at a dammed pond within the Sakaerat Biosphere Reserve in northeastern Thailand. At 00.57 hrs on 24 July 2013, we observed an adult N. cf. albocinctus preying on a F. hansenae egg clutch (Fig. 1). The egg clutch was attached to a blade of grass and was located roughly 50 cm above the pond surface. Embryos within the egg clutch had not started neural fold development, and there was minimal egg jelly covering the outer surface of the clutch. Based on the developmental stage of embryos, the egg clutch was laid within 24 hours prior to the predation event. We concluded our observations five minutes later, with no change in spider behaviour. No female frog was observed to be caring for the egg clutch or present within the vicinity of the egg clutch during our observations. Little is known about spider predation of frog eggs in Southeast Asia. However, in the Neotropics, spiders in the family Pisauridae are known to prey on adult and juvenile frogs (Menin et al., 2005). To our knowledge, Nilus species predation of frog eggs has not been reported for arboreal- breeding frogs in Southeast Asia thus far.
เอกสารอ้างอิง :
Poo, S., Erickson, F., Mason, S., & Nissen, B. (2017). Predation of Feihyla hansenae (Hansen s bush frog) eggs by a nursery web spider. Herpetological Bulletin, 139, 36-37.
