Success breeding the Lesser night gecko

In mid December 2008, 15 pairs of the Lesser night gecko, Nactus coindemierensis, on loan from the Mauritian Government, arrived at the Durrell Herpetological Dept. These tiny geckos, which grow to only 6cm in length and lay eggs weighing just 0.2g, are part of an ex-situ captive breeding and reintroduction project. This species is now only found on four small islets, where they would once have existed in dense populations throughout the Mascarene islands. Habitat destruction and invasive species are the main factors threatening the survival of this species.

Durrell has been working for many years with the Mauritian Wildlife Foundation and National Parks and Conservation Service, to rebuild habitats and ecosystems around the offshore islands of Mauritius. Our aim is to re-establish the endemic fauna communities and food webs that used to exist before being removed. A key component of this process has been the restoration of endemic reptile communities, a project led by Dr. Nik Cole who has been working with 6 species of skink and gecko around islands off Mauritius.

Currently the largest population of this lesser night geckos can be found on Ilot Vacoas and was estimated at ~369 in 2008. However a neighbouring coralline islet, Ile Marianne, is four times the size of Ilot Vacoas and would make an the ideal site to reintroduce the geckos. However establishing a population requires a large number of animals and a target of 200 was identified. The only way to generate this number of animals for release was through a captive breeding programme; any fewer and the geckos would simply disperse and probably never cross paths again! So instead 10% of the Ilot Vacoas population was captured and transported to Durrell to start the captive breeding programme. This has been a really exciting opportunity for the site in Jersey to work closely with the conservation programmes overseas.

As with any new project, initial optimism is always met by challenges but our enthusiasm in the Herpetological Dept. never wanes! One of the potential issues we tackled was the variety of invertebrate prey we could offer to the geckos, nutrition has so often been the key to greater productivity and reproductive quality in many of our other projects, our geckos now eat everything from firebrats to tropical woodlice, bean weevils and aphids. Charlotte Goble, a Keeper in the Herpetological Dept. said: “We knew through Nik’s experience and observations in Mauritius, that these geckos are attracted to lick fallen fruit and nectar in their natural environment. Using this information we formulated a fruit, honey, calcium and multivitamin mixture that could be offered to the geckos as a dietary supplement, delivering additional calcium to our females and their developing eggs.”

By February we were thrilled to find our first eggs, once these were in the incubator, productivity seemed to slow for a short time, it seemed our newly arrived females just needed a little time and a good diet to acclimatise and get back into the swing of it!

After a tense few months, sneaking a look through the incubator window at every chance, we excitedly observed our first hatchling out of the egg and shedding his skin for the first time on 2nd June 2009; “Finding that first hatchling was just awe inspiring, seeing such a tiny animal, perfect, self sufficient out of his egg and in the middle of shedding his skin for the first time sums up why reptiles and amphibians are so utterly captivating for me” Charlotte said. We now have three surprisingly large hatchlings, feeding well on a variety of invertebrates. It will certainly be interesting in the coming months to make new observations of how the hatchlings grow and change, perhaps to see if their little bright orange tails stay quite so incredible!

The incubator holds more promise with eggs still to hatch from early spring and more recently laid eggs just beginning to develop, our females are looking in great health with some just showing the first cream coloured patch of a new egg developing and others lugging around a single proportionately huge egg almost ready to pop. The months ahead clearly hold more little surprises and exciting sights.

Field work for this project has been supported through funding provided by the Darwin Initiative of the UK Government.

Equipment for the breeding programme was kindly donated by La Ferme Tropicale.