Stable carbon isotope ratios as indicators of marine versus terrestrial inputs to the diets of wild and captive tuatara (Sphenodon punctatus)
- 1 January 1999
- journal article
- research article
- Published by Taylor & Francis Ltd in New Zealand Journal of Zoology
- Vol. 26 (3), 243-253
- https://doi.org/10.1080/03014223.1999.9518193
Abstract
Stable carbon isotope analysis was used to examine feeding relationships of wild tuatara on Stephens Island and captive tuatara in New Zealand institutions. We first measured δ13C in three food items of wild tuatara. Pectoral muscle of fairy prions (a seabird eaten seasonally by tuatara) was significantly enriched in 13C compared with whole bodies of wild insects (darkling beetles and tree weta). Values for 813C in blood cells varied significantly among wild tuatara of different life‐history stages. Male tuatara were more enriched in 13C than were females or juveniles, suggesting that males prey more heavily on seabirds. Insect foods of captive tuatara varied dramatically in δ13C; this is attributed to differential consumption of plant material derived from the C3 and C4 photosynthetic pathways. Blood cells from four different groups of captive tuatara differed significantly in δ13C. This was perhaps related to assimilation of insects with different δ13C values, and cannot be attributed to differences in seabird predation as captive tuatara do not have access to seabirds. For wild tuatara on Stephens Island, stable carbon isotope analysis provides support for the dietary information available from behavioural observations, gut analyses and measurements of plasma composition.Keywords
This publication has 33 references indexed in Scilit:
- Breeding the Tuatara Sphenodon punctatus at Auckland ZooInternational Zoo Yearbook, 2007
- Relationships between Corticosterone Concentration and Season, Time of Day and Confinement in a Wild Reptile (Tuatara,Sphenodon punctatus)General and Comparative Endocrinology, 1998
- The trophic status of marine turtles as determined by stable isotope analysisMarine Ecology Progress Series, 1998
- Conventional and isotopic determinations of shorebird diets at an inland stopover: the importance of invertebrates andPotamogeton pectinatustubersCanadian Journal of Zoology, 1996
- Reproductive cycles of male and female tuatara (Sphenodon punctatus) on Stephens Island, New ZealandJournal of Zoology, 1992
- Incubation of eggs of tuatara, Sphenodon punctatusJournal of Zoology, 1990
- Nitrogen and Carbon Isotope Ratios in Seabird Rookeries and their Ecological ImplicationsEcology, 1988
- Age and dietary differences of recently extinct Indian Ocean tortoises ( Geochelone s. lat. ) revealed by carbon isotope analysisProceedings of the Royal Society of London. B. Biological Sciences, 1986
- Stable-Carbon Isotope Ratios as a Measure of Marine Versus Terrestrial Protein in Ancient DietsScience, 1982
- Grasshopper Food Web Analysis: Use of Carbon Isotope Ratios to Examine Feeding Relationships Among Terrestrial HerbivoresEcology, 1978