Herpetology Notes, volume 8: 489-492 (2015) (published online on 03 October 2015)

Diet of the endemic Malagasy day gecko Phelsuma modesta leiogaster Mertens, 1970 in an urban environment

Charlie Gardner1,* and Louise Jasper2

Abstract. The day gecko genus Phelsuma provides an ideal group in which to investigate the behavioural adaptations that permit survival in urban ecosystems, because it spans the spectrum of degradation tolerance from obligate forest specialists to human commensals. We opportunistically recorded foraging observations of Phelsuma modesta leiogaster in a house and garden in urban Toliara, southwest Madagascar, and found the diet to consist principally of natural and artificial sources of sugar (including fruits, honey, sugar, syrups and chocolate), with only 2 % of foraging observations consisting of invertebrates. Many Phelsuma species consume fruit, pollen or nectar in their diets, and we suggest that the specialisation on sugary foods may permit some species to adapt to urban environments where the availability of such food sources may be artificially high.

Keywords: Adaptation; Anthropogenic environment; Degradation tolerance; Madagascar; Urban ecology

Introduction and P. quadriocellata (Glaw and Vences, 2007; Gardner and Jasper, 2009; pers. obs.). However, little is known The day geckos (genus Phelsuma) are a radiation about the diets of these species or the mechanisms that of over 40 species of medium-sized to large arboreal, allow them to adapt to such anthropogenic environments. diurnal geckos distributed throughout Madagascar and Here we report observations of the diet of P. modesta the islands of the Western Indian Ocean, as well as leiogaster from an urban environment in Madagascar to coastal areas of East Africa (Harmon et al., 2008; Rocha contribute to filling this knowledge gap. et al., 2010). They provide an ideal group in which to investigate the behavioural mechanisms of habitat Methods selectivity because members of the genus span the spectrum of degradation tolerance from obligate forest From 22nd March 2014 to 11th April 2014, and again specialists such as P. flavigularis, P. guimbeaui and P. from 13th October 2014 to 3rd November 2014, we ornata (Glaw and Vences, 2007; Bungard et al., 2014) recorded all foraging and drinking observations of P. m. to strict human commensals rarely if ever recorded leiogaster within a house and garden in urban Toliara, in forests, such as P. modesta (Glaw and Vences, the capital of Atsimo Andrefana region in south-west 2007). Many other species may be common in urban Madagascar (23°21.0 S, 043°40.8 E). The house was environments but also occur in primary or degraded a single-story, concrete walled structure surrounded forests (e.g. P. abbotti, P. dubia, P. hielscheri, P. on two sides by well-vegetated gardens planted with laticauda, P. lineata, P. madagascariensis, P. mutabilis a range of widely-cultivated trees (including papaya, banana, oranges, dates, guava and neem (Azadirachta indica)), as well as locally-endemic trees (Delonix spp., Euphorbia spp., Adansonia spp.) and succulents (Aloe spp., Kalanchoe spp.). At least 17 reptile species occur in 1 Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Toliara including seven species of gecko that have been Canterbury, Kent, CT2 7NR, UK; recorded on the property (Gardner and Jasper, 2009; 2 Cité Sisal 13, Toliara 601, Madagascar. Gardner et al., 2015), although only P. m. leiogaster, the ������������������������������������* Corresponding author e-mail: cg399�����@�kent.ac.uk���������� introduced and nocturnal Hemidactylus frenatus and the 490 Charlie Gardner & Louise Jasper

Figure 1. Proportion of foraging and drinking observations of Phelsuma modesta leiogaster from a house in urban Toliara, southwest Madagascar, divided by type of food/water. ‘Fruits’ included pineapple, pineapple juice, bananas, grated carrot, raisins and dates, ‘Artificial sugars’ comprised flavoured syrups (mint and blackcurrant flavours), refined white sugar, unrefined brown sugar, chocolate, mint-flavoured sweets, sugary coconut confections, custard pudding and sweetened milk.

nocturnal, ground-dwelling Paroedura picta regularly coconut macaroons (a baked confection), custard occur within the house. We recorded all opportunistic pudding and sweetened milk left over from breakfast observations of P. m. leiogaster foraging and drinking cereals (Fig. 2). The species was also sometimes active within the house and garden as we carried out other at night in well lit places, suggesting that it may be tasks; observations were thus concentrated in areas predating nocturnal insects attracted to the lights: we where we spent the most time during daylight hours, i.e. never reported such predation attempts during data our office, the kitchen, and the bathroom. We did not collection, though we have observed it at other times. control either for survey effort nor the distribution of We did not make any foraging observation outside the available food resources across space or time. house and only rarely observed the species in the garden

Results We made 49 observations of foraging or drinking by P. m. leiogaster, of which 20 % consisted of drinking water (from buckets, the walls of a shower and drinking vessels). Of the remaining foraging observations 2.6 % concerned invertebrates (a single, failed attempt to capture a cockroach), 15.4 % involved honey, 28.6 % involved fruits and vegetables (including pineapple, pineapple juice, bananas, grated carrot, raisins and dates), and almost half (46.2 %) involved artificial sources of sugar (Fig. 1). The latter category included a diverse range of items including flavoured syrups (mint and blackcurrant flavours, consumed in both dilute and Figure 2. Adult female Phelsuma modesta leiogaster licking concentrated forms), refined white sugar, unrefined honey from a kitchen surface in an urban house, Toliara, brown sugar, chocolate, mint-flavoured sweets, sugary southwest Madagascar. Image: Louise Jasper. Diet of the endemic Malagasy day gecko in an urban environment 491 at all, though it sometimes basked on sunlit tree trunks garden, suggesting that the two species occupy different adjacent to the building. niches, exploit different food sources, and have been able to colonise urban environments through different Discussion behavioural adaptations. Differences in the behavioural and dietary plasticity of Phelsuma species, and thus their Our data should be interpreted with caution because ability to adapt to novel, anthropogenic environments, most observations were made in the kitchen and office may be an important determinant of extinction risk as where we spent most of our time, but where fruits and forest environments within their range suffer further artificial sugar sources were concentrated: these food degradation and loss. types may therefore be over-represented in our sample. However a range of insect and other invertebrate orders Acknowledgements. We thank the editor and an anonymous were also present in these areas as they were throughout reviewer whose comments helped improve an earlier version of the house (which was never treated with any form of this manuscript. chemical insecticide or repellent), yet day geckos were less frequently encountered in other rooms and we only References rarely observed predation attempts on invertebrates (i.e. Bauer, A.M. (2003): Gekkonidae, geckos. In:����������������������� The Natural History once during this study). of Madagascar, pp. 973–977. Goodman, S.M., Benstead, J.P. Our observations suggest that urban P. m. leiogaster Eds., Chicago, University of Chicago Press. populations in Toliara may subsist to a large extent on Bègue, J.-F., Sanchez, M., Micheneau, C., Fournal, J. (2014): natural and artificial sources of sugar. Like most geckos New record of day geckos feeding on orchid nectar in Reunion worldwide, Phelsuma are thought to be primarily Island: can lizards pollinate orchid species? Herpetology Notes 7: 689–692. insectivorous (Bauer 2003), however many species Buckland, S., Cole, N.C., Aguirre-Gutiérrez, J, Gallagher, L.E., include significant amounts of fruit, pollen or nectar in Henshaw, S.M., Besnard, A., Tucker, R.M., Bachraz, V., their diets (Murphy and Myers, 1996; Olesen et al., 2002, Ruhomaun, K., Harris, S. (2014): Ecological effects of the 2012; Deso et al., 2008; Minnaar et al., 2013; Bègue et invasive giant Madagascar day gecko on endemic Mauritian al., 2014; Taylor and Gardner, 2014) and several may be geckos: applications of binomial-mixture and species distribution the obligate pollinators of endemic plant species in the models. PLoS ONE 9: e88798. Bungard, M.J., Jones, C., Tatayah, V., Bell, D.J. (2014): The Mascarenes (Nyhagen et al., 2001; Hansen et al., 2006; habitat use of two species of day geckos (Phelsuma ornata Hansen and Müller, 2009). Other species are known and Phelsuma guimbeaui) and implications for conservation to steal pollen from bees (Clémencet et al., 2013) and management in island ecosystems. Herpetological Conservation milk honeydew from planthoppers (Fölling et al., 2001), and Biology 9: 551–562. while some of the largest Phelsuma are known to predate Clémencet, J., Aubert, C., Blottière, D., Sanchez, M. (2013): vertebrates including other geckos (Garcia and Vences, Kleptoparasitism in the endemic gecko Phelsuma inexpectata: 2002; Buckland et al., 2014). pollen thefts from foraging honeybees on Réunion. Journal of Tropical Ecology 29: 251–254. It may be that the dietary and behavioural plasticity of Deso, G., Probst, J.-M., Sanchez, M., Ineich, I. (2008): Phelsuma the genus predisposes some species to adapt to novel, inexpectata Mertens, 1966 et Phelsuma borbonica Mertens, anthropogenic environments. For example, the nocturnal 1942 (Squamata: Gekkonidae): deux geckos potentiellement activity we observed suggests that P. m. leiogaster may pollinisateurs de l’île de La Réunion. ����������������������Bulletin de la Société be able to take advantage of artificial light sources Herpétologique de France 126: 9-23. to prey on nocturnal invertebrates. In particular, we Fölling, M., Knogge, C., Böhme, W. (2001): Geckos are milking speculate that the high dependence of many species honeydew-producing planthoppers in Madagascar. Journal of Natural History 35: 279–284. on natural sugars (from fruit and nectar) may be a key Garcia, G., Vences, M. (2002): Phelsuma madagascariensis kochi mechanism allowing some members of the genus to (Madagascar day gecko): diet. 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Accepted by Gonçalo Rosa