Black Leg Poison Dart Frog, Neará
© 2005 Henk Wallays (1 of 11)
Phyllobates bicolor color patterning is very striking. The dorsum and sides are a uniform golden yellow or orange, as well as the dorsal surfaces of the upper arm and thigh (Myers et al. 1978). In contrast, the dorsal surfaces of the forearm and calf are black, and may or may not have dense yellow (or sometimes blue) spotting (Myers et al. 1978). The ventrum may be completely black, or washed with light orange, light gold, or bluish green (Myers et al. 1978). There is occasionally a black patch on the throat (Silverstone 1976). The tympanum is partly yellow-orange and partly black (Silverstone 1976). In some individuals, the tip of the snout is black (Silverstone 1976). Irises are black or reddish-brown (Silverstone 1976).
This species, like P. terribilis, exhibits an ontogenetic color change; juveniles are dark brown to black in color, with two yellowish dorsolateral bands. As the frogs reach maturity, the dorsolateral stripes disappear, and the frogs become more brightly colored. In contrast, the juvenile pattern of light stripes on a dark background is retained into adulthood in other members of the P. bicolor group, P. aurotaenia, P. lugubris and P. vittatus (Myers et al. 1978; Silverstone 1976).
Phyllobates bicolor closely resembles P. terribilis, but P. bicolor is smaller in size and has legs and venter of a different hue than the body color (Myers et al. 1978).
Distribution and Habitat
Life History, Abundance, Activity, and Special Behaviors
Like other dendrobatids, Phyllobates bicolor are diurnal and are very active. Little has been published on the reproductive behavior of this species in the wild. Zimmermann (1989) has published sonograms of P. bicolor calls, and reports that in captivity, P. bicolor, males initiate courtship by giving a "long-range" courtship call. The female then follows the male to a covered egg deposition site. Once the female approaches within 8 cm, the male emits a "short-range" courtship croak call, ceasing before the female oviposits. Circling and body-anal touching was observed but not amplexus. In captivity, a single female may lay up to three clutches of 12-20 eggs per month. The male moistens the clutch at irregular intervals (hydric brooding). Tadpoles hatch in about 14 days, after which the male transports them to a water-filled brooding site (Zimmermann 1989).
Trends and Threats
Relation to Humans
Possible reasons for amphibian decline
General habitat alteration and loss
As is true of other species in the genus Phyllobates, this species produces batrachotoxins. However, captive-born and bred dendrobatid frogs lack toxicity, since the toxins are acquired at least in part from dietary sources such as ants, mites or beetles (Daly et al. 1980; Daly et al. 1992; Dumbacher et al. 2004). In contrast, the toxins persist in wild-caught animals even when they are maintained in captivity (Daly et al. 1978).
Myers et al. (1978) have speculated that there might be either hybridization or a cline between P. bicolor and P. aurotaenia in the upper San Juan drainage, due to the intermediate size and coloration of the Phyllobates found there.
Daly, J. W., Myers, C. W., Warnick, J. E., and Albuquerque, E. X. (1980). ''Levels of batrachotoxin and lack of sensitivity to its action in poison-dart frogs (Phyllobates).'' Science, 208, 1383-1385.
Daly, J.W., Secunda, S.I., Garraffo, H.M., Spande, T.F., Wisnieski, A., Nishihara, C., and Cover, J.F. (1992). ''Variability in alkaloid profiles in neotropical poison dart frogs (Dendrobatidae): genetic versus environmental determinants.'' Toxicon, 30, 887-898.
Dumbacher, J.P., Wako, A., Derrickson, S.R., Samuelson, A., Spande, T.F., and Daly, J.W (2004). ''Melyrid beetles (Choresine): a putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds.'' Proceedings of the National Academy of Sciences of the United States of America, 101, 15857–15860.
IUCN, Conservation International, and NatureServe. (2006). Global Amphibian Assessment: Phyllobates bicolor. www.globalamphibians.org. Accessed on 7 May 2008.
Myers, C. W., Daly, J. W., and Malkin, B. (1978). ''A dangerously toxic new frog (Phyllobates) used by Emberá Indians of Western Colombia, with discussion of blowgun fabrication and dart poisoning.'' Bulletin of the American Museum of Natural History, 161, 307-366.
Silverstone, P.A. (1976). ''A revision of the poison arrow frogs of the genus Phyllobates Bibron in Sagra (Family Dendrobatidae).'' Natural History Museum of Los Angeles County Science Bulletin, 27, 1-53.
Zimmermann, H. (1989). ''Conservation studies on the 'dart-poison' frogs Dendrobatidae in the field and in captivity.'' International Zoo Yearbook, 28, 31-44.
Written by Kip Green and Kellie Whittaker (crewkip AT berkeley.edu), UC Berkeley
First submitted 2005-02-18
Edited by Kellie Whittaker (2009-10-26)
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