Herpetology Notes, volume 7: 575-576 (2014) (published online on 3 October 2014)

Predation of intermedia egg-clutches by tadpoles of Discoglossus pictus in Sicily

Daniel Escoriza

The painted Discoglossus pictus is an anuran Other examples of oophagy in anuran larvae are also native of northwestern Africa and some islands from the provided in the literature, including Rana temporaria on central Mediterranean, including Sicily (Ben Hassine & Bombina variegata, Epidalea calamita, Hyla arborea Nouira, 2012; Escoriza, Ben Hassine & Boix, 2014). It and conspecifics (Heuser, 1970), Bufo bufo on Epidalea is widely distributed in Sicily, where it occupies a broad calamita (Beebee, 1977), Leptodactylus pentadactylus range of habitats (Turrisi, Lo Cascio & Vaccaro, 2007). on Rhinella roqueana (Wells, 1979), Pelobates cultripes Discoglossus pictus breeds in small water bodies, such and Pelodytes punctatus on Epidalea calamita (Tejedo, temporary ponds, where it frequently co-occurs with 1991), Lithobates sylvaticus on Anaxyrus americanus Hyla intermedia and Pelophylax bergeri (Capula, 2007; (Petranka et al., 1994), Lithobates clamitans on Escoriza & Boix, 2014). Lithobates sylvaticus (Petranka & Kennedy, 1999), In March 2014, I observed the predation of eggs of Scaphiopus couchii on Anaxyrus speciosus (Dayton Hyla intermedia by several tadpoles of Discoglossus & Fitzgerald, 2005), Bufotes viridis and Isthmohyla pictus (Fig. 1A, B), in a temporary pond near Cefalù pseudopuma on conspecific spawns (Crump, 1983; (norhern Sicily; Fig. 1C). This pond had a surface area Vlček, Kudláček & Jablonski, 2013) and Dendrobates of 50.2 m² and an average depth of 12 cm, with a water ventrimaculatus and Phrynohyas resinifictrix, temperature of 14.7ºC (at 13:00 h, local time). No phytotelmata breeding species, also on conspecific other anurans (adult or larvae) were found in this pond. eggs (Summers, 1999; Schiesari et al., 2003). These This behavior, not previously described in the genus observations suggest that oophagy can play an important Discoglossus, is an effective mechanism to regulate the role in the regulation of species co-occurrence in small presence of other anuran species, since in subsequent water bodies, such ephemeral ponds and tree holes. days no tadpole of H. intermedia was found in the pond. Thus D. pictus, an early breeder species (Capula, 2007), Acknowledgements. I wish to thank Mar Comas and Diogo B. likely benefits from this strategy to eliminate potential Provete for their helpful comments. competitors, such H. intermedia (a later breeder; Lapini, 2007). This is because most of the tadpoles are trophic generalists (Altig et al., 2007; Schiesari et al., 2009), References and the small size of the pond did not allow for spatial Altig, R., Whiles, M.R., Taylor, C.L. (2007): What do tadpoles segregation in the use of the trophic resources (species really eat? Assessing the trophic status of an understudied and of genus Hyla forage more frequently along the water imperiled group of consumers in freshwater habitats. Freshwater column than Discoglossus species; Díaz-Paniagua et Biology 52: 386-395. al., 2005). However both species can co-occur locally, Beebee, T.J. (1977): Environmental change as a cause of natterjack toad (Bufo calamita) declines in Britain. Biological Conservation in larger-sized ponds (between 446-2929 m²) with 11: 87-102. more complex mesohabitat structure (Escoriza & Boix, Ben Hassine, J., Nouira, S. (2012): Répartition géographique 2014). et affinités écologiques des Amphibiens de Tunisie. Revue d’Écologie. (Terre & Vie) 67: 437-457. Capula, M. (2007): Discoglossus pictus. In: Lanza, B., Andreone, F., Bologna, M.A., Corti, C., Razzetti, E. (Eds.), Fauna d’Italia, Amphibia. Calderini, Bologna, pp 312-318. Institute of Aquatic Ecology, University of Girona, Campus Crump, M. L. (1983): Opportunistic cannibalism by Montilivi, 17071 Girona, Spain. larvae in temporary aquatic environments. American Naturalist E-mail: [email protected] 121: 281-289. 576 Daniel Escoriza

Figure 1. A) Detail of the temporary pond illustrating several Discoglossus pictus tadpoles and Hyla intermedia eggs deposited on the aquatic vegetation; B) enlarged detail: the red arrow indicates a tadpole of Discoglossus pictus eating an egg of Hyla intermedia; C) map of Sicily (southern Italy) showing the study area (red dot).

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