Herpetology Notes, volume 13: 813-816 (2020) (published online on 05 October 2020)

Aposematic polyphenism: Antipredator mechanism of juveniles of exilis (Cruz, 1980) (Amphibia, Anura, ), in southeastern Brazil

Lucas Rosado Mendonça1, Ubiratã Ferreira Souza2, Maria Eduarda Bernardino Cunha3, Leticia Keiko Watanabe4, Thiago Silva-Soares5, and Alexander Tamanini Mônico6,*

Several anurans have morphological, physiological, al., 2019). Also, polyphenism of some arthropods is and behavioural antipredator mechanisms (Toledo and associated with facultative aposematism, were the Haddad, 2009; Toledo et al., 2011; Mailho-Fontana et al., species can assume aposematic colours under specific 2013; Ferreira et al., 2019). Polyphenism is the change environmental conditions (Sword, 2002; Despland and of skin colour patterns in response to an environmental Simpson, 2005). Here we follow the definition of Toledo stimulus (e.g., antipredator response; Hanlon et al., and Haddad (2009) and Ferreira et al. (2019). 1999). Some anurans have cells to Polyphenetic behaviour has been recorded in several promote instantaneously or gradually colour changing species within the Phyllomedusidae. Pithecopus (Toledo and Haddad, 2009; Ferreira et al., 2019). azureus (Cope, 1862), Pithecopus megacephalus This strategy is usually associated with to (Miranda-Ribeiro, 1926), Pithecopus rohdei (Mertens, resemble the environment background favouring the 1926), Phasmahyla cochranae (Bokermann, 1966), use of different substrates (Toledo and Haddad, 2009), (Lutz, 1924) and also Phasmahyla which may decrease the risk of (Ferreira et jandaia (Bokermann and Sazima, 1978) change skin colour from purplish during night activity to greenish during daytime resting (Toledo and Haddad, 2009). Phasmahyla guttata was the first species of the family observed displaying dynamic polyphenism (i.e., fast colour change) (Machado et al., 2015). 1 Departamento de Biologia , Laboratório de The genus Phasmahyla Cruz, 1991, is composed by Herpetologia, Museu de Zoologia João Moojen da eight species endemic to the Atlantic Forest (Frost, Universidade Federal de Viçosa, Vila Giannetti 32, Viçosa, Minas Gerais 36570-900, Brazil. 2020), breeding in mountain streams from eastern Minas 2 Departamento de Biologia, Laboratório de Estudos Gerais, southern Bahia to eastern Paraná State (Cruz et Herpetológicos e Paleoherpetológicos da Universidade al., 2008; Pereira et al., 2018; Frost, 2020). Phasmahyla Federal Rural de Pernambuco, Rua Dom Manoel de exilis (Cruz, 1980) was described from Santa Teresa, Medeiros s/n, Recife, Pernambuco 52171-900 Brazil. State of Espírito Santo. Its known distribution is limited 3 Departamento de Zoologia, Instituto de Biociências, to a few localities in the State of Espírito Santo and Universidade Federal do Rio Grande do Sul, Avenida Bento southern Bahia (Frost, 2020). Gonçalves 9500, Porto Alegre, Rio Grande do Sul 91509- 900, Brazil. At 9:00 pm, 25 January 2019, during a nocturnal 4 Departamento de Ciências Biológicas, Universidade Federal herpetological survey in the Estação Biológica de Santa do Espírito Santo, Campus Goiabeiras, Avenida Fernando Lúcia, Municipality of Santa Teresa, State of Espírito Ferrari 514, Vitória, Espírito Santo 29075-910, Brazil. Santo, southeastern Brazil (19.9749ºS, 40.5317°W; 5 Projeto Herpeto Capixaba, Rua Silvino Grecco 813, Vitória, WGS84, 720 m a.s.l.), six juvenile individuals of Espírito Santo 29090-230, Brazil. Phasmahyla exilis were found perched on herbaceous 6 Instituto Nacional de Pesquisas da Amazônia, campus V8, vegetation at a stream bank. At first, the individuals were Avenida André Araújo 2936, Manaus, Amazonas 69067-375, Brazil. light green with black spots (Fig. 1A). Approximately * Corresponding author. E-mail: two minutes after handling, all six individuals started [email protected] changing colouration by displaying red/orange spots on 814 Lucas Rosado Mendonça et al.

Figure 1. Juveniles of Phasmahyla exilis displaying colour polyphenism as antipredator mechanism at Estação Biológica de Santa Lúcia, Municipality of Santa Teresa, State of Espírito Santo, Brazil. A) dorsum was light green with black spots; B) and C) instantaneously after handling, red spots can be seen on the dorsum; D) after approximately one minute, dorsum was red/orange- brown. Photos by Alexander T. Mônico.

the dorsum (Fig. 1B, C). After a minute, the individuals change skin colour during daytime. Collected specimens became totally red/orange-brown with black spots (Fig. were deposited at Coleção de Anfíbios do Museu de 1D). The difference of colour between the individuals Biologia Mello Leitão from Instituto Nacional da Mata before and after displaying polyphenism can be seen in Atlântica, located in the Municipality of Santa Teresa, Figure 2. Espírito Santo, Brazil (vouchers: MBML - Anfíbios The six individuals were placed in a plastic container 11589 - 11592, 11594, 11595). with leaves and water to maintain humidity and taken We observed juveniles of Phasmahylla exilis changing to laboratory. About 40 min later, all six individuals their colours from green to red/orange-brown contrarily returned to their original light green colour (Fig. 3). To to adults of Phasmahyla gutatta (Machado et al., 2015). repeat the handling test also under laboratory condition, Also, Phasmahyla gutatta secreted a transparent sticky an individual of P. exilis was handled and once again substance, which was not observed in P. exilis juveniles. changed the skin colour to reddish. Then this reddish Six antipredator mechanisms were reported for P. exilis individual was placed back into the container with adults by Ferreira et al. (2019), including a poisonous the other individuals. Promptly, all individuals started secretion probably similar to that seen in P guttata. changing to red as well. The tested individuals did not The other mechanisms were camouflage (background Antipredator mechanism of juveniles of Phasmahyla exilis in southeastern Brazil 815

avoid detection by matching the background colour (Toledo and Haddad, 2009; Ferreira et al., 2019). We agree with Machado et al. (2015) who suggest that the change may also happen to enhance the contrast between the aposematic colours of the flanks and the background dorsal pattern. As a rule, to be effective, aposematic colours must contrast with background colour (Siddiqi et al., 2004). The mechanism here reported would make it even more effective. We suggest that polyphenism in may be linked to aposematic colouration, similar to that seen in arthropods (Sword, 2002). In our study the individuals tested were juveniles and their aposematic colour in the flanks was not yet totally developed. Perhaps, as suggested by Ferreira et Figure 2. Comparison between green (before handling) and al. (2019) for other species, in addition to antipredator red/orange-brown (after handling) individuals of Phasmahyla purposes, aposematism may also work as an intraspecific exilis at Estação Biológica de Santa Lúcia, Municipality communication mechanism for juveniles of P. exilis. of Santa Teresa, State of Espírito Santo, Brazil. Photo by So, further research is necessary to understand the real Alexander T. Mônico. objective of this colour change. Is it really associated to the aposematism in this species? If so, is it related to any kind of intraspecific communication, since one already changed individual triggered the change in all the others? matching), aposematism of hidden parts, contraction and Certainly, a better understanding of these strategies jump away, but no changes of colour were described. could evidence mechanisms associated with Because the tested P. exilis were juveniles (snout-vent interspecific or intraspecific interactions and provide length [SVL] = 16.73 ± 1.27 mm), it is not possible to greater knowledge about this species natural history. confirm if aposematic polyphenism also occurs in adults

(SVL = males 29 mm; female: unknown) (Haddad et al., Acknowledgments. We thank Instituto Chico Mendes de 2013). As Tonini et al. (2010) provided a clue in their Conservação da Biodiversidade/Sistema de Autorização e Informação Figure 2, we expect that the occurrence of polyphenism em Biodiversidade for the sampling permit (Process n. 52838-6) and in adults could be confirmed with further observations. Herpeto Capixaba project for field support. FAPES/VALE/FAPERJ Polyphenism has been reported for other species to Nº 01/2015 – Pelotização, Meio Ambiente e Logística for funding. Museu Nacional do Rio de Janeiro, Associação dos Amigos do Museu Nacional do Rio de Janeiro and the Museu de Biologia Prof. Mello Leitão (Instituto Nacional da Mata Atlântica) for allowing sampling at the study site. We also thank Augusto V. Tozani and Bryan C. Martins for help during fieldwork. Esteban D. Koch and Rodrigo B. Ferreira for their careful revision of the manuscript. ATM thanks Conselho Nacional de Desenvolvimento Científico e Tecnológico for a scholarship (Process n. 142153/2019-2).

References

Cruz, C.A.G. (1982): Conceituação de grupos de espécies de Phyllomedusinae brasileiras com base em caracteres larvários (Amphibia, Anura, ). Arquivos da Universidade Federal Rural do Rio de Janeiro 5: 147–171. Cruz, C.A.G. (1990): Sobre as relações intergenéricas de Phyllomedusinae da Floresta Atlântica (Amphibia, Anura, Hylinae). Revista Brasileira de Biologia 50: 709–726. Cruz, C.A.G., Napoli, M.F., Fonseca, P.M. (2008): A new species of Phasmahyla Cruz, 1990 (Anura: Hylidae) from the state of Figure 3. Individual starting to change back to green colour Bahia, Brazil. South American Journal of Herpetology 3: 187– after being left alone. Photo by Alexander T. Mônico. 195. 816 Lucas Rosado Mendonça et al.

Despland, E., Simpson, J. (2005): Surviving the change to warning Mailho-Fontana, P.L., Antoniazzi, M.M., Toledo, L.F., Verdade, colouration: density-dependent polyphenism suggests a route V.K., Sciani, J.M., Barbaro, K.C., et al. (2013): Passive and for the evolution of aposematism. Chemoecology 15: 69–75. active defense in toads: The parotoid macroglands in Rhinella Faivovich, J., Haddad, C.F.B., Baêta, D., Jungfer, K., Álvares, marina and Rhaebo guttatus. Journal of Experimental Zoology G.F.R., Brandão, R.A., et al. (2010): The phylogenetic 9999: 1–13. relationship of the charismatic poster , Phyllomedusinae Pereira, E.A., Rocha, L.C.C., Folly, H., da Silva, H.R., Santana, D.J. (Anura, Hylidae). Cladistics 26: 227–261. (2018): A new species of spotted leaf , genus Phasmahyla Ferreira, R.B., Lourenço-de-Moraes, R.L., Zocca, C., Duca, C., (Amphibia, Phyllomedusidae) from Southeast Brazil. PeerJ 6: Beard, K.H., Brodie Jr, E.D. (2019): Antipredator mechanisms of 1–22. post-metamorphic anurans: a global database and classification Siddiqi, A., Cronin, T.W., Loew, E.R., Vorobyev, M., Summers, system. Behavioral Ecology and Sociobiology 73: 69. K. (2004): Interspecific and intraspecific views of color signals Frost, D.R. (2020): species of the world: an online in the strawberry poison frog pumilio. Journal of reference. Version 6.0 Available at: https://amphibiansoftheworld. Experimental Biology 207: 2471–2485. amnh.org/ Accessed on 30 January 2020. Sword, G.A. (2002): A role for phenotypic plasticity in the Haddad, C.B.F., Toledo, L.F., Prado, C.P.A., Loebmann, D., evolution of aposematism. Proceedings of the Royal Society of Gaspararini, J.L., Sazima, I. (2013): Guia dos Anfíbios da Mata London 269: 1639–1644. Atlântica: Diversidade e Biologia. São Paulo, Brasil, Anolis Toledo, L.F., Haddad, C.F.B. (2009): Colors and some morphological Books Editora. traits as defensive mechanisms in anurans. International Journal Hanlon, R.T., Forsythe, J.W., Joneschild, D.E. (1999): , of Zoology 2009: 1–12. conspicuousness, and polyphenism as antipredator Toledo, L.F, Sazima, I., Haddad, C.F.B. (2011): Behavioural defences of foraging on Indo-Pacific coral reefs, with defences of anurans: an overview. Ethology Ecology & a method of quantifying crypsis from video tapes. Biological Evolution 23: 1–25. Journal of the Linnean Society 66: 1–22. Tonini, J.F.R., Carão, L.M., Pinto, I.S., Gasparini, J.L., Leite, Machado, I.F., Mengucci, R.C., Mendes, H.F., Moroti, M.T. (2015): Y.L.R., Costa, L.P. (2010): Non-volant tetrapods from Reserva Polyphenism: Defensive colour behaviour of Phasmahyla guttata Biológica de Duas Bocas, State of Espírito Santo, Southeastern (A. Lutz, 1924) (Amphibia, Anura, Hylidae). Herpetology Notes Brazil. Biota Neotropica 10: 339–351. 8: 467–470.

Accepted by Fabrício Oda