Dominant tuatara males are ruling their own roost but not
doing much for the genetic diversity of the populations,
according to a Victoria University researcher.
PhD student Jennifer Moore, who has studied the mating system
of tuatara for four years, found that the iconic New Zealand
reptile, of which there are just about 70,000 worldwide, was
also a bit of a homebody and didn't like to move about much,
even when its habitat was disrupted.
She said that, like other reptiles, tuatara mating was
dominated by a small proportion of large males, which could
decrease the genetic diversity of a population.
"Annually, male reproduction is highly skewed in the wild and
in captivity," she said.
"More than 80 percent of offspring from a captive population
on Little Barrier Island were sired by one male and multiple
paternity was found in approximately 18 percent of these
clutches.
"This has led to reduced genetic variation in the recovering
Little Barrier Island population."
She also found that these long-lived reptiles have a stable
social structure that can be influenced by human-induced
habitat modification.
Tuatara genes showed the population changes appeared to be
driven by changes to habitat in the past and a sedentary
lifestyle in the absence of dispersal or migration.
That was illustrated on Stephens Island in the Marlborough
Sounds where land was cleared for pasture, affecting the make
up of tuatara populations.
Ms Moore's results should allow management and captive
breeding programmes to maximise genetic diversity and help
select individuals to found new translocated populations.
Conservation programmes could possibly increase the genetic
diversity of a small population by removing the dominant male
and allowing the other smaller males to mate more, she said.
Originally from Michigan in the United States, Ms Moore has
already researched snake ecology, particularly green
anacondas and eastern massasauga rattlesnakes Her next
research project will be in Alaska studying toads.
