HYPSIBOAS PULCHELLUS (Montevideo Tree Frog, Ranita de Zarzal).

VILLANOVA JORGELINA; SAIBENE PABLO; AGOSTINI MARIA GABRIELA

HERPETOLOGICAL REVIEW

Herpetological Review

Año: 2015

0018-084X

Predation is one of the main causes ofmortality in natural amphibian populations and may occur inany stage of the life cycle (Zug et al. 2001. Herpetology. An IntroductoryBiology of Amphibians and Reptiles. 2nd ed. AcademicPress, San Diego. 630 pp.). Many authors have pointed out thatarachnids (mainly Aranae) are one of the most important predatorsof tadpoles in the Neotropics. Most of these records belongto Pisauridae, Ctenidae, Lycosidae, Sparassidae, and Theraphosidaefamilies (Menin et al. 2005. Phyllomedusa 4:39?47). However,predation on adult and juvenile amphibians has been poorlydocumented, mainly due to the difficulty of obtaining direct recordsin the field (Pombal 2007. Rev. Bras. Zool. 24:841?843).At 2125 h on 9 November 2013, we recorded two predationevents of Hypsiboas pulchellus juveniles by wolf spiders (Lycosidae).Both observations were made in flooded grasslands ofPunta Lara Nature Reserve (34.8043°S, 58.0319°W; WGS84), BuenosAires, Argentina. In the first case, the predator was an adultmale Lycosa erythrognatha. It was collected and deposited in thecollection of Invertebrate Zoology, La Plata Museum (MLP-Ar19385). The second predator corresponded to a species belongingto an undescribed genus of the Lycosidae (Fig. 1). This specimenwas not collected. During the period we observed both predationevents the larval cycle of H. pulchellus was concluding (havingstarted in spring) and we noted high densities of juveniles.Spiders are potential predators of both juvenile and adult anurans.Significant linear correlations between the body lengthsof prey and predator have been demonstrated, with the size ofthe spider being similar or slightly smaller than the anuran prey(Menin et al. 2005. Phyllomedusa 4:39?47). The body lengths ofH. pulchellus span 1.95?5 cm (Maneyro and Carreira 2012. Guíade Anfibios del Uruguay. Ediciones de la Fuga, Montevideo, Uruguay.207 pp.), whereas the largest wolf spiders can reach morethan 30 mm body length (Jocqué and Dippenaar-Schoeman2015. Spider Families of the World. Royal Museum for CentralAfrica, Tervuren, Belgium. 336 pp.); therefore, we can infer thatthese spiders can prey on both juvenile and adult stages of H.pulchellus.Here we present the first records of two species of lycosid spiderspreying on H. pulchellus. Given that spiders of the Lycosidaeare abundant in the Argentine Pampas grasslands (Platnick 2014.www.wsc.nmbe.ch; 15 Jun 2015), they could have an importantrole in regulating H. pulchellus populations.We thank Jorge Berneche and Jorge Williams for identifying thespecimens, and Kini Roesler for editorial suggestions. This studywas funded by CREOI, Neotropical Grassland Conservancy andAmphibian Conservation in Agroecosystems Initiative (CoAnA).