Herpetology Notes, volume 8: 239-241 (2015) (published online on 2 May 2015)

Further records of reptiles and amphibians utilising () domatia in New Guinea

Paul M. Oliver1,*, Fred Parker2 and Oliver Tallowin3

Introduction Daru Island, Western Province, Papua New Guinea In addition to flowers and fruits, many have Daru Island has long been inhabited, and at the time other specialised structures that facilitate mutualistic of fieldwork in October 1972 most trees had long since relationships with animals (Heil, 2010), and many been harvested for building materials and firewood, animals show evidence of facultative or obligatory leaving a terrestrial vegetation dominated by grassland associations with vegetative structures that provide key with scattered trees to 10 m in height. Many of the resources such as retreats or breeding sites (e.g. Lehtinen remaining trees, especially paperbarks in the et al., 2004; Cornu and Raxworthy, 2010). However with Melaleuca tended to host at least one ant plant, and the prominent exception of bromeliad breeding frogs in many cases three or more, with two different ant (Romero et al., 2010), plant-herpetofauna mutualisms plant species (Hydnophytum sp. and Myremecodia sp.) based around provision and utilisation of specialised present. The latter (identified by the their spiny caudex vegetative structures have been rarely reported. with no apparent openings and one or two stout stems), In the Asia-Pacific region several plant genera in the when opened were found to contain no reptiles or family Rubiaceae are characterised by swollen tuberous amphibians. In contrast when the former (smooth caudex bases with hollow chambers and passages (domatia) with many obvious openings and thin twiggy stems) (Huxley, 1978). These chambers often provide refugia were sliced open (by FP), skinks (Cryptoblepharus and nest sites for , which in turn have been shown sp.), frogs (Litoria congenita (Peters and Doria 1878)) to provide nutrients such as carbon and nitrogen to their and geckos (Gehyra sp. and Lepidodactylus pumilus epiphyte hosts (Huxley, 1978; Tresender et al., 1995). (Boulenger 1885)(Figure 1A)) were found. During However, in addition to ants there are records of other extensive fieldwork on Daru Island and the adjacent animals using domatia as retreat and breeding sites Trans-Fly area of the New Guinea mainland, the first including hylid and microhylid frogs (New Guinea), three of these species were frequently observed using skinks (New Guinea and Australia) and geckos (Fiji a wide range of habitats. In contrast, Lepidodactylus and Vanuatu) (Neill, 1946; Zweifel, 1956; Tyler, 1976; pumilus (specimens now lodged at the Museum of Ryan, 2000; Horner, 2007; Ineich, 2008). Here we report Comparative Zoology at Harvard - MCZR135529–30, additional observations of reptiles and amphibians MCZR135354–5, R137586, MCZR139420) were only utilising ant plants in New Guinea. collected from within the internal chambers of ant plants. Many pairs of eggs were also found in domatia. The eggs were paired (suggesting they came from geckos) and of a size consistent with L. pumilus rather than the larger Gehyra sp. The domatia in which deposition occurred were often barely wider than the eggs and many plants 1 Research School of Biology, Australian National University, contained multiple clutches of eggs (Figure 1B). Canberra 0200, Australia and, Department of Sciences, GPO Box 666, Museum Victoria, Melbourne, Victoria, Australia 2 PO Box 5623, Townsville Queensland 4810, Australia 3 Department of Zoology, Tel Aviv University, 69978, Tel Aviv, Israel * Corresponding author email: [email protected] 240 Paul M. Oliver et al.

Discussion These observations raise two questions: a) could ant plant domatia be a key resource for some vertebrate taxa, and b) could vertebrates be an important source of nutrients for ant plants? With respect to the first question, it is not at all surprising that small arboreal reptiles and frogs make use of ant plant domatia. They provide appropriately sized humid retreats and, potentially, also a ready supply of ants which many frogs and lizards eat, including species from Melanesia (e.g. Richards and Oliver, 2010). However, most reptiles and amphibians recorded from domatia also utilise other microhabitats, and only one poorly known gecko species has thus far been exclusively recorded from ant plants (Ineich, 2008). Based on the data available at this stage, it would be premature to assert that any of these species is entirely dependent on ant plant domatia. The second possibility, that domatia may facilitate mutualism with vertebrates (especially frogs and lizards), was suggested long ago by Neill (1946). He Figure 1. A) Lepidodactylus pumilis found inside noted that domatia in the region around Port Moresby Hydnophytum ant plant. B) Presumed Lepidodactylus pumilis were extensively used by a number of small arboreal eggs found inside Hydnophytum ant plant at Daru, Western vertebrates (at times at very high densities) and suggested Province, Papua New Guinea. Photographs F. Parker. that vertebrate wastes deposited in domatia might be a key source of nutrients (Neill, 1946). It has since been confirmed that ant-plants do indeed absorb key nutrients via their domatia (Tresender et al., 1995). Subsequent work in other regions has also revealed novel mutualisms where plants use unique vegetative structures to capture Kamiali Wildlife Management Area, Morobe Province, key resources (e.g. carbon and nitrogen) from vertebrate Papua New Guinea partners, especially species that grow in nutrient limited A Hydnophytum sp. ant plant was found (by OT) on environments, such as epiphytes (Romero et al., 2010; a tree felled at the Kamiali Research Station [~530m, Clarke et al., 2009). However, Neill’s hypothesis that -07.29463 S, 147.09372 E] during February, 2012. The a mutualism sometimes exists between Melanesian ant tuber of the plant was roughly 20 cm in diameter and plants and small arboreal vertebrates remains untested. was removed from a branch that would have been in the canopy prior to felling. On removing the Hydnophytum Acknowledgements. We thank Bruno Corbara, Patrick Couper, from its mount, a small lizard dropped from its base and Fred Kraus, Stephen Richards and George Zug for contributing escaped. The entire plant was then placed in a plastic observations and comments to this manuscript. bag and shaken, and a Lepidodactylus sp. (BPBM 40272, SVL 36.0 mm) was captured. The tuber was References then sectioned and no further geckos were recovered. The captured specimen is provisionally assigned to Clarke, C.M., Bauer, U., Lee, C.C., Tuen, A.A., Rembold, K., Lepidodactylus cf. orientalis Brown and Parker 1977 Moran, J.A. (2009): Tree shrew lavatories: a novel nitrogen sequestration strategy in tropical pitcher plants. Biology Letters pending further work. We cannot confirm that the first 5: 632–635. lizard that escaped was conspecific with the second, but Cornu, C., Raxworthy, C.J. (2010): Discovery of a novel association in size, colouration, and overall appearance they were between baobab trees (Adansonia) and the poorly known very similar. No other Lepidodactylus were observed in Standing’s day gecko Phesulma standingi in Madagascar. 3 weeks at this site. Herpetological journal 4: 281–284. Further records of reptiles and amphibians utilising ant plant domatia in New Guinea 241

Heil, M. (2010): Ant–Plant Mutualisms. eLS (http://www.els.net/ WileyCDA/ElsArticle/refId-a0022558.html) Horner, P. (2007): Systematics of the snake-eyed skinks, Cryptoblepharus Wiegmann (Reptilia: Squamata: Scincidae) – an Australian-based review. The Beagle, Records of the Museums and Art Galleries of the Northern Territory, Supplement 3: 21–198. Huxley, C.R. (1978): The ant plants and Hydnophytum (Rubiaceae) and the relationships between their morphology, ant occupants, physiology and ecology. New Phytologist 80: 231–268. Ineich, I. (2008): A new arboreal Lepidodactylus (Reptilia: Gekkonidae) from Espiritu Santo Island, Vanuatu: from egg to holotype. Zootaxa 1918: 26 –38. Lehtinen, R.M., Lanonoo, M.J., Wassersug, R.J. (2004): Phytotelm- breeding anurans: past, present and future research. In: Ecology and Evolution of Phytotelm-breeding Anurans, p. 1–9, Lehtinen, R.M., Ed., Miscellaneous Publications, Museum of Zoology, University of Michigan 193. Neill, W.T. (1946): An unusual habitat for frogs and lizards. Copeia 4: 258. Richards, S.C., Oliver, P.M. (2010): A new species of scansorial Cophixalus from the Kikori Integrated Conservation and Development Area, Papua New Guinea. Journal of Herpetology 44: 555–562. Romero, G.Q., Nomura, F., Gonçalves, A.Z., Dias, N.Y., Mercier, H., Conforto Ede, C., Rossa-Feres Dde, C. (2010): Nitrogen fluxes from treefrogs to tank epiphytic bromeliads: an isotopic and physiological approach. Oecologia 162: 941–949. Ryan, P. (2000): Fiji’s Natural Heritage. 2nd edition. Exisle Publishing, Wollombi. New South Wales. 288 pp. Treseder, K.K., Davidson, D.W.,Ehleringer, J.R. (1995): Absorption of ant-provided carbon-dioxide and nitrogen by a tropical epiphyte. Nature 375: 137–139. Tyler, M.J. (1976): Frogs, Collins, Sydney, Australia. Zweifel, R.G. (1956): Results of the Archbold expeditions. No. 72 microhylid frogs from New Guinea, with descriptions of new species. American Musesum Novitates 1766.

Accepted by Christoph Liedtke