Herpetology Notes, volume 13: 337-339 (2020) (published online on 23 April 2020)

Defensive colour behaviour in two hylids in the eastern Amazon: Boana dentei (Bokermann, 1967) and Scinax ruber (Laurenti, 1768)

Fillipe Pedroso-Santos1,*, Pedro Hugo Esteves Silva2, Patrick Ribeiro Sanches1, and Carlos Eduardo Costa-Campos1

Abstract. Polyphenism has been well documented in anurans as an anti-predator mechanism. Herein, we report two cases of this defensive behaviour in Boana dentei and Scinax ruber in Amapá State, eastern Amazon, Brazil. Both species changed colour when exposed to different microhabitats. Our field observations suggest that this phenomenon is important for anurans to avoid potential predators.

Keywords. Polyphenism, Hylidae, Predators, Northearn Brazil

Many anurans display a wide variety of defensive and the cochranae, colour behaviours. The defensive colour behaviour of P. guttata, P. jandaia, (Stegen et al., 2004; Toledo polyphenism type belongs to the category of deceptive and Haddad, 2009; Choi and Jang, 2014; Machado et colouration, in which it is the ability of an individual al., 2015). In general, this phenomenon, in anurans, to generate different phenotypes by altering of their has been related with anti-predator mechanism and dorsal colouration with the rearrangement of their thermoregulation (Hoppe, 1979; King and King, 1991; chromatophores, involving physiological control of King et al., 1994). In this note, we report for the first the skin structures (Toledo and Haddad, 2009). Some time polyphenism displayed by two hylids in the eastern species may change their dorsal colouration very Amazon region: Boana dentei (Bokermann, 1967) and quickly, while another take hours, days or weeks to Scinax ruber (Laurenti, 1768). occur, but a rapid colour change is most important when Scinax ruber is a medium sized treefrog arboreal, an anuran becomes stationary following a change in nocturnal, and can be observed on bushes and trees in microhabitat, making it less detectable in its and secondary forest and disturbed areas (e.g., urban area) avoiding potential predators (Stegen et al., 2004; Toledo (Lima et al., 2005), with geographic distribution in and Haddad, 2009). the Amazon Basin of Brazil, Bolivia, Peru, Colombia, Polyphenism has been documented in several species of Ecuador, the Guianas, eastern Panama, and Trinidad anurans of the family Hylidae, such as Bokermannohyla and Tobago (Frost, 2018). circumdata, B. alvarengai, Dryophytes japonicus, The Amapa Treefrog, B. dentei, is endemic from Serra Hyliola regilla, Scinax fuscomarginatus and S. hayii; do Navio, Amapá State, Brazil, with records also in French Guiana (Bokermann, 1967; Frost, 2018). During fieldwork in a rapid and reptile assessment at a wetland area (0.9066°N, 52.0073°W, datum WGS84; 146 m a.s.l.), municipality of Serra do 1 Universidade Federal do Amapá, Departamento de Ciências Navio, Amapá State, Brazil, we found on 15 June 2017 Biológicas e da Saúde, Laboratório de Herpetologia, Campus at 17:30 h, an adult B. dentei (SVL = 74 mm; Weight Marco Zero do Equador, 68.903-419, Macapá, AP, Brazil. = 8 g) under a vegetation. The specimen was exposed 2 Universidade Federal do Amapá, Departamento de Ciências to daylight and exhibited a dorsal yellow-whitish Biológicas e da Saúde, Laboratório de Zoologia, Campus Marco Zero do Equador, 68.903-419, Macapá, AP, Brazil. colouration (Fig. 1A). After its capture, we move him * Corresponding author. E-mail: to a less illuminated area, and it was observed that there [email protected] was a change in dorsal colouration to brown-yellowish 338 Fillipe Pedroso-Santos et al.

Figure 1. Boana dentei and Scinax ruber displayed polyphenism. A) Dorsal yellow-whitish colouration and B) dorsal brown- yellowish colouration of B. dentei. C) Dorsal yellowish-brown colouration and D) dorsal cream-brown colouration of S. ruber.

(Fig. 1B). The entire event lasted 20 min. The individual with different illumination (Toledo and Haddad 2009). was photographed, but not collected. Although other species have been observed, as Boana On 6 December 2017 at 19:30 h, we found an adult cinerascens, B. multifasciata and Dendropsophus cf. S. ruber (SVL = 41 mm; Weight = 4 g) in a PVC pipe microcephalus, only B. dentei and S. ruber exhibited inside a water tank in an urban area in the municipality this defensive behaviour in our study, and our field of Macapá, Amapá State, Brazil (0.0129°S, 51.0830°W, observations suggest that the polyphenism exhibited datum WGS84; 7 m a.s.l.). The specimen was exhibiting by both species is strictly related to a camouflage a dorsal yellowish-brown colouration (Fig. 1C). After mechanism because its colourations have adapted to its capture by hand, we noticed a quick exchange in the microhabitat that were placed. According to Stegen its colour, exhibiting a cream-brown colouration after et al. (2004), this rapid colour change in anurans is 10 min (Fig. 1D). The did not return to the initial important when there are changes in the microhabitat, colour. This individual was not collected. making them less noticeable to their predators. A similar polyphenism was described for B. circumdata, in which the dorsal colouration was changed in areas Defensive colour behaviour in two hylids in the eastern Amazon 339

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Accepted by Clarissa Canedo