Sex and Food in a Cave During Daytime, a Possible Way to Escape Predators for the Nocturnal Madagascar Gekkonid Paroedura Tanjaka Nussbaum & Raxworthy, 2000
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Herpetology Notes, volume 9: 187-190 (2016) (published online on 05 September 2016) Sex and food in a cave during daytime, a possible way to escape predators for the nocturnal Madagascar gekkonid Paroedura tanjaka Nussbaum & Raxworthy, 2000 Ivan Ineich1,* and Thierry Bourgoin2 Madagascar is a well-known herpetofaunal outcrops (Nussbaum and Raxworthy, 2000; Glaw and biodiversity hotspot (Jenkins et al., 2014). Among Vences, 2007). All specimens reported by Nussbaum & reptiles, several genera show a high species diversity Raxworthy (2000) were observed while active at night with numerous undescribed or recently described taxa (20:00-22:00), mostly at the base of tsingy cliffs (1.0 to most of them with poor knowledge on their biology 4.0 m above ground) and sometimes on branches and and ecology available. Paroedura Günther 1879 is a tree trunks 0.5 to 2.5 m high. Occurrence of P. tanjaka widely distributed Madagascar gekkonid genus living in caves was briefly mentioned and they reported one in rainforest, dry forest, arid savanna and mountain diurnal observation in a cave approximately 30 m from habitat (Glaw and Vences, 2007). The genus comprises its entrance. 18 described species, among which 16 are endemic to Madagascar and the remaining two to the Comoros (Jackman et al., 2008; Hawlitschek and Glaw, 2012; Glaw et al., 2014). Paroedura species are also common and sometimes endemic in several karstic massifs of Madagascar. Paroedura tanjaka Nussbaum & Raxworthy 2000 is one of the largest species in the genus (Figure 1) reaching up to 102 mm snout-vent length with a total length up to 180 mm (Nussbaum and Raxworthy, 2000; Glaw et al., 2014). It is endemic to Mahajanga Province in western Madagascar and known only from Tsingy de Bemahara and Tsingy de Namoroka (Nussbaum and Raxworthy, 2000; Bora et al., 2009; Figure 1. Paroedura tanjaka (field tag 1996I), Tsingy de Raselimanana, 2013). This nocturnal gecko has not been Namoroka, Madagascar. found outside of deciduous dry forests with limestone 1 Muséum national d’Histoire naturelle, Sorbonne Universités We here report on the diurnal activity of the nocturnal Institut de Systématique, Évolution et Biodiversité (ISyEB) P. tanjaka in a cave environment. During a field trip UMR 7205 (CNRS, MNHN, UPMC, EPHE) CP 30 to Namoroka National Park (16°28’S, 45°20’E) in (Reptiles) – 25, rue Cuvier, 75005 Paris, France September 2012 (see Allorge and Haevermans, 2015), 2 Muséum national d’Histoire naturelle, Sorbonne Universités several (not counted but about a dozen of observations) Institut de Systématique, Évolution et Biodiversité (ISyEB) UMR 7205 (CNRS, MNHN, UPMC, EPHE) CP 50 specimens of P. tanjaka were observed active in caves (Entomology) – 45, rue Buffon, 75005 Paris, France during daytime (all times of the day) always in areas * Corresponding author e-mail: [email protected] of complete darkness far from the cave entrance. They 188 Ivan Ineich & Thierry Bourgoin were active, not hidden, and were not disturbed by the Mautz (1982) from Mexico where lizards feed in caves torch light of people entering caves. Among them, we on carrions. Also, predominantly diurnal geckos of the even observed a copulation event (Figure 2) in one of genus Phelsuma will occasionally switch to nocturnal the numerous cave galleries of the tsingy (6 September activity (Bringsoe, 2006; Rösler, 2007; II pers. obs. 2012, 16h30, 16°28’08”S 45°20’52”E). in the Seychelles) in order to obtain food attracted by artificial lighting in urban areas, showing their behavioral plasticity. The caves in the Tsingy de Namoroka area are largely gecko-predator free. They do host some saurophagous snakes, but few other predators like birds and mammals (except bats which are not reptile predators). Saurophagy in snakes is common in Madagascar and is frequent among nocturnal snakes (Glaw and Vences, 2007). Several Madagascar lizard species have evolved behavioral or physiological specializations to avoid such ophidian predation, while some snakes have in turn evolved traits to enhance predation success on lizards (Bauer and Russell, 1992; Krysko, 2005; Kaloloha et al., 2011; Ito and Mori, 2012; Rosa et al., 2012). Paroedura tanjaka has been reported in the diet of Lycodryas [=Stenophis; Hawlitschek et al., 2013] by Nussbaum & Raxworthy (2000). Glaw & Vences (2007) considered the whole genus Lycodryas as predators of Figure 2. Copulation of Paroedura tanjaka in a cave on 6 Paroedura spp. September 2012 (16°28’08”S - 45°20’52”E) at 16h30. Tsingy de Namoroka, Madagascar. It could be hypothesized that day time activity (particularly reproduction) in a cave for a nocturnal gecko could therefore be another habit adaptive shift as a way to avoid predation by the numerous saurophagous sympatric nocturnal snakes, or by other vertebrates (birds and mammals). However we cannot exclude We suggest that this novel observation is likely due to that some nocturnal snakes also shift to day activity a relaxation of nocturnal diet activity/behaviour as the in caves, following their preys. We suggest that during species has exploited a novel niche, the darkness of cave copulation at night those lizards are potentially more environments allowing avoidance of many predators, vulnerable to predators, particularly large sized species and providing constant prey availability. This cave like P. tanjaka, since their doubled volume (male above environment possesses numerous interconnected caves female when copulating) is more visible and thus less and galleries and several arthropods are encountered, cryptic (we often observed solitary lizards active at including troglobites (=cave dwellers) that are living on night outside caves on whitish karst rocks). Copulation the rich food resources that accumulate (Soulier-Perkins in caves during the day can be an efficient way for P. et al., 2015), as well as resting nocturnal arthropod tanjaka to avoid nocturnal snake predators which do species escaping the daytime heat or predators (e.g. not often enter caves during the day. Note however that erebid moths; Figure 3). This allows day and night 24-hr some Madagascar snakes seem to be completely related activity/prey availability for the geckos. It is interesting to caves as trogloxenes like Alluaudina mocquardi to note that nocturnal lizards like geckos (rather than Angel 1939 (Lanza, 1990), indicating that a constant most diurnal lizards) seem to have some behavioral food supply is present. plasticity to change their activity period when better Our observations might represent the first step of conditions can be obtained. This was indeed noted for some adaptive shift of this taxon to a cave environment other Madagascar lizards which were able to change (Howarth, 1987), which is common for many lizards their behavior according to the predator type (Ito and and snakes at different kind of extent from occasional Mori, 2012). A remarkable case is also reported by cave inhabitant to permanent inhabitant (Lanza, 1990; Sex and food in a cave during daytime, a possible way to escape predators 189 Figure 3. A wall in a gallery of the Tsingy de Namoroka, Madagascar, with five specimens of Cyligramma duplex Guenée, 1852 (Insecta, Lepidoptera, Erebidae), putative prey items for P. tanjaka (September 3rd, 2012; 16°28’08”S - 45°20’52”E, 17h30). Grismer et al., 2015). Evolutionary mechanisms related Acknowledgments. The authors wish to thank Lucile to behavioral plasticity could therefore lead P. tanjaka Allorge, Thomas Haevermans, Marc Gansuana, and Charlotte to become active during daytime in caves, preying on Razafindrakoto for logistical support and scientific organization during fieldwork at Tsingy de Namoroka. Special thanks also to a rich entomofauna food resource and copulating there the Namoroka National Park staff, its guides and the inhabitants to avoid most of their numerous nocturnal vertebrate of the village of Vilanandro for their useful help. Fieldwork was predators. If eggs are also laid in caves is unknown but a carried out in the framework of cooperation with the Département possibility. Such a kind of strength relationship between de Biologie Animale, Université d’Antananarivo, Madagascar. karst caves and their species could have a high survival Authors are grateful to the Malagasy authorities for collection and value for the species since it is never encountered in export permits. Financial support was obtained through Labex areas without karst caves and the same is true for many founds. Special thanks to Pr Joël Minet (MNHN-Paris) for his confirmation of the identification of the lepidopteran specimen other karst dwelling gecko species all over the world of Figure 3, and to Frank Glaw, Christopher Raxworthy, and Stu which are often highly endemic and threaten species. Nielsen for their comments on a earlier drafts. Further studies of nocturnal lizard activity during day time in caves should be made using camera traps taking References pictures at regular time intervals with a special dark flash light so not to affect natural behavior. Allorge, L., Haevermans, T. 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