A brighter future for tuatara

PhD graduand Jennifer Moore studied the mating system of tuatara as a way to ensure the reptiles are healthy and genetically diverse in the future.

“Knowledge of mating patterns is useful for conservation of threatened and endangered species, but for many reptiles this information is largely unknown. It’s great to have some research complete about the mating systems of tuatara – they are such an iconic species in NZ,” says Ms Moore, who graduated from Victoria University last week.

Tuatara mating is dominated by a small proportion of large males, which can decrease the genetic diversity of a population.

Over the course of her research, Ms Moore combined behavioural and genetic techniques to investigate the mating system of tuatara.

“Annually, male reproduction is highly skewed in the wild and in captivity. More than 80 per cent of offspring from a captive population on Little Barrier Island were sired by one male and multiple paternity was found in approximately 18 per cent of these clutches. This has led to reduced genetic variation in the recovering Little Barrier Island population,” she says.

She also found that these long-lived reptiles have a stable social structure that can be influenced by human-induced habitat modification.

“Stephens Island tuatara show genetic structuring that appears to be driven by changes to their habitat in the past and a sedentary lifestyle in the absence of dispersal or migration,” says Ms Moore.

Her results will improve management and captive breeding efforts by providing guidelines for maximising genetic diversity and selecting individuals to found new translocated populations.

“A good understanding of the mating system and behavioural interactions is essential for captive breeding, re-introductions, translocations and ultimately, persistence of tuatara populations.

“I’ve been lucky to be part of a bigger picture throughout my research; there’s a very strong research group in this field at Victoria University.

“Since completing my PhD, I’ve been linking in with other projects looking at things like functional genes, immunity and parasite resistance,” says Ms Moore.

There are approximately 70,000 tuatara worldwide. The majority of these are on Stephens Island in the Marlborough Sounds. Scientists are working to stabilise the tuatara population.