National Resource Material Green and Black Poison Frog (Dendrobates Auratus)
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Indicative 10 Project National Resource Material Green and Black Poison frog (Dendrobates auratus) Michelle T. Christy and Win Kirkpatrick 2017 Department of Primary Industries and Regional Development 3 Baron-Hay Court, South Perth, WA 6151 An Invasive Animals CRC Project Contents Summary ............................................................................. 2 Key Messages ................................................................... 2 Classification ................................................................... 2 Common names ................................................................ 3 Biology and Ecology ................................................................ 3 Identification ................................................................... 3 Behaviours and Traits ......................................................... 4 Food and Foraging ............................................................. 4 Reproduction and Lifecycle ................................................. 5 Habitat ......................................................................... 5 Global Range ........................................................................ 5 Potential for Introduction ........................................................ 6 Potential for Eradication.......................................................... 7 Impacts ............................................................................... 7 Economic ........................................................................ 7 Environmental ................................................................. 7 Social ......................................................................... 8 Legislation ........................................................................... 8 Image Library ....................................................................... 9 Copyright Licence Restrictions of Use ..................................... 9 Image Library - Green and black poison frog (Dendrobates auratus) ... 16 References ......................................................................... 20 Green and Black Poison Frog - Indicative 10 Project i Summary Summaries based on assessments carried out in (García-Díaz 2014a, b, c) Species on VPC List 2007? Yes Species on the live import list (EPBC Act 1999)? Yes Risk of establishment: Moderate Pathways: Intentional (pet/zoo trade) Key Messages Introduction pathway – primarily illegal pet trade, and also for legal education purposes (i.e., zoos) Impact to Economy – may fetch high prices in the illegal pet trade because of high desirability. The species may also be used as barter for drugs and other items on the black market Impact to Environment – species is known to carry chytrid fungus and other pathogens that may have negative impacts on native wildlife. If introduced frogs’ poison secretions persist in the wild, poisoning of naïve species may occur. Breeding - Unlike most frogs, females lay eggs in moist, sheltered areas rather than in water. After hatching, the male transports the tadpoles on his back to small pools of water, often water accumulated in the centre of bromeliads. Classification Dendrobates auratus (Girard, 1855) Class: Amphibia Order: Anura Family: Dendrobatidae Genus: Dendrobates Species: auratus Figure 1. Dendrobates auratus. Photo: Greg Gilbert (CC BY 2.0) 2 Invasive Animals CRC Common names green and black poison frog, gold arrow poison frog, golden poison-arrow frog, green and black poison-arrow frog, green and black poison-dart frog, green and golden poison-arrow frog, green poison-arrow frog, green poison frog Biology and Ecology Identification The green and black poison frog (Dendrobates auratus) is one of the most variable of all poison frogs in appearance (Eaton 1941). It is typically mint-green interspaced with black. However, colours vary from forest, lime, emerald green, turquoise, or even cobalt blue or pale yellow contrasted with a dark shade from brown to black. Adult females are larger than males, usually over 25 mm, whereas males average 19 mm. Figure 2. Dendrobates auratus. Photo Josh More (CC BY-NC-ND 2.0) Green and Black Poison Frog - Indicative 10 Project 3 Figure 3. Dendrobates auratus. Photo: Pavel Kirillov (CC BY-SA 2.0) Behaviours and Traits The green and black poison frog is semi-arboreal (Eaton 1941). It hunts, sleeps and mates in the trees, returning to the ground intermittently to travel as it is too small to move from canopy to canopy. To assist climbing, the frog has small, sucker-like discs on the ends of its toes that provide a suction grip that is mildly adhesive. The frog is a popular species kept and bred by hobbyists worldwide (Mattison 1987; Walls 1994; Zimmermann 1986). The Hawaiian introduced populations on Oahu may be the principle source of all stock for the international commercial pet trade (Walls 1994). Food and Foraging In their native range, the green and black poison frog primarily consume ants and mites (Caldwell 1996). Incidentally, the alkaloid toxin in their poison skin glands is purportedly derived from the ants that are ingested (Caldwell 1996). The tadpoles are omnivorous and feed on algae and small invertebrates that inhabit the tiny pool in which the tadpoles live (McKeown 1996). In Hawaii, the introduced Gold Dust Day Gecko (Phelsuma laticauda) has been observed to consume poison frog tadpoles (Chan et al. 2007). 4 Invasive Animals CRC Reproduction and Lifecycle Green and black poison frogs congregate in large groups before mating. Although they mate in groups, they are patch territorial and will defend their patch from other males. Males are polygynous during the breeding season; however, the females compete for, and guard, their mates from other females (Crump 1996; Summers 1989, 1990), and may even destroy the eggs of competitors (Summers 1989). Unlike most frogs, females lay eggs in moist, sheltered areas. The eggs are fertilized then protected by the male (Crump 1996; McKeown 1996; Summers 1990; Summers et al. 1999; Walls 1994; Wells 1978; Zimmermann 1986). When the tadpoles hatch the male transports them on his back to small pools of water, often accumulated in the centre of bromeliads (Crump 1996; Eaton 1941; Summers 1990; Wells 1978; Zimmermann 1986). Habitat The green and black poison frog occurs in various moist, vegetated valleys (Cochran and Goin 1970; McKeown 1996; Oliver and Shaw 1953; Smith and Kohler 1977; Walls 1994). Global Range The green and black poison frog is native to Colombia, Costa Rica, Nicaragua, and Panama. It occurs in the humid lowlands from south-eastern Nicaragua on the Atlantic slope and south-eastern Costa Rica on the Pacific slopes to north western Colombia (IUCN 2017; Somma 2017). The species was intentionally introduced to the upper Manoa Valley on Oahu (Hawaii) in 1932, for mosquito control (Cochran and Goin 1970; McKeown 1996; Oliver and Shaw 1953; Smith and Kohler 1977; Walls 1994). The initial introduction was 206 individuals from Taboga or Taboguilla Islands in Panama (McKeown 1996; Silverstone 1975). A few descendant populations still persist in the mountains and valleys of Oahu (Somma 2017). Dendrobatids were not known from Maui, Hawaii (McKeown 1996), but the detection of the green and black poison frog in the early 2000s indicate they are established on the island. In early 2002 a single frog was collected from Wailuku, Maui after several years of reported sightings (Somma 2017). Green and Black Poison Frog - Indicative 10 Project 5 Figure 4. Map showing the native range of Dendrobates auratus (red). Image courtesy Smithsonian Tropical Research Institute (September 2017). Potential for Introduction Green and black poison frog has been transported to Australia illegally and legally for exhibition in zoos (García‐Díaz and Cassey 2014). Because the highest risk is via the illegal wildlife trade, controlling imports is difficult (García-Díaz 2014c). However, the scarcity of records of this species in the illegal trade indicates that it may not be common in Australia (García‐Díaz and Cassey 2014). If captive frogs escape, the risk of an incipient population establishing is moderate (García-Díaz 2014c). As there are no native Dendrobatidae species in Australia (Cogger 2014) and their colouration distinctive, they would be relatively easily to identify. Based on the short distances the species moves from breeding to wintering habitat (Kraus 2009; Mattison 1987; Summers 1989), it is unlikely to rapidly disperse if a population establishes in Australia. 6 Invasive Animals CRC Potential for Eradication While green and black poison frogs are established in Hawaii, no data on methods of control are currently available. Some control techniques may be similar to those already used in Australia for cane toads (Rhinella marinus) (e.g., Crossland et al. 2012; Kelehear et al. 2012; Pizzatto and Shine 2012; Saunders et al. 2010), and smooth newt (Lissotriton vulgaris) (Dodd and Kay 2013). Methods used to control coqui frog (Eleutherodactylus coqui) overseas should also be considered, particularly since both species spawn eggs away from waterbodies (e.g., Sin and Radford 2007; Tuttle et al. 2008; Witmer et al. 2015). Although green and black poison frogs should be easy to identify, their small size and relatively sedentary nature may hamper early detection (Heyer et al. 1994). Moreover, seasonality may impact detectability; the reproductive season, when the adults are concentrated in the breeding sites, may increase the chance of observing individuals (Vitt and Caldwell