INTRODUCTION

Lygodactylus williamsi, commonly known as the Electric Blue Day Gecko, is a diurnal dwarf gecko species native to Tanzania. It is restricted to two small Forest Reserves — Kimboza and Ruvu — and inhabits an extremely limited range estimated at under 8 km². The species is Critically Endangered (IUCN Red List) and the IUCN strongly recommends its inclusion in CITES Appendix I or II due to ongoing population decline. These geckos live exclusively on screw pine (Pandanus rabaiensis) in swampy lowland habitats. A single plant may host a small group consisting of one male, one or more females and their juveniles.

Deforestation is the primary threat to the species, but extensive collection for the pet trade has also contributed to significant wild population losses (Flecks et al., 2012). Males are bright blue with dark throat stripes, visible preanal pores and hemipenal bulges. Females range from green to brown and can resemble juveniles or subordinate males. Both sexes have an orange underside and colour intensity varies with mood and temperature. Adults reach a snout-vent length (SVL) of 5–8 cm.

These are highly active geckos, and males are territorial. Unlike many day gecko species, they are inquisitive and may readily take insects from the keeper’s hands in captivity.

CAPTIVE HUSBANDRY

VIVARIUM

Electric Blue Day Geckos are extremely active and require a well-planted vivarium to thrive. Glass terrariums with mesh tops provide excellent ventilation, which is essential for this species. A recommended enclosure size for an adult pair is approximately 45 × 45 × 60 cm. A single male may be housed with multiple females provided adequate space and visual barriers are available.

A planted vivarium is strongly advised, with live plants such as Devils Ivy, Pothos and Bromeliads creating necessary cover. Bamboo hollows are ideal for both hiding and egg-laying. Tropical vines and upright branches increase vertical space and encourage natural climbing behaviour. A drainage layer should be included to prevent waterlogging. This may consist of a 1–2 inch layer of clay balls, a mesh separator and a deep growing substrate such as planting soil or a bark-based mixture.

LIGHTING

Full-spectrum lighting, including UVB, is essential. A photoperiod of approximately 12 hours is recommended. Medium UVB levels are suitable, while UVA plays an important role in intraspecific recognition, colour perception and natural foraging behaviour. A visible-light basking bulb may be used in combination with a UV source to provide appropriate lighting conditions.

TEMPERATURE AND HUMIDITY

A daytime thermal gradient of 24–30°C should be provided, with a drop to 18–22°C at night (Encyclopedia of Life). Relative humidity must remain high, ranging from 50–85%, simulating damp forest conditions. Spraying or misting several times daily is recommended, and an automated misting or drip system is ideal. These geckos frequently drink from water held at the bases of bromeliads or droplets on leaves. A small, clean water dish should always be available.

FOOD, SUPPLEMENTS AND WATER

A varied diet should be provided including commercially available meal replacement powders (MRPs) for day geckos, fruits, fruit flies, mini mealworms, phoenix worms, wax worms, small cockroach nymphs and small crickets. MRPs should be available daily, with live insects offered several times per week. Larger feeder insects can injure the gecko and should be avoided. Black crickets, in particular, may bite.

Banana or other soft fruits may be mixed with MRPs. Baby foods should be used sparingly due to high sugar content. All feeder insects must be gut-loaded for 24–48 hours prior to feeding using tropical fish flakes, vegetables, fruits, calcium and vitamins. Dehydration is a common cause of cannibalism in feeder insects, so hydration sources should be available.

Calcium supplementation is critical, especially for egg-laying females, and should be provided with each insect feed or added to fruit slurries and MRPs. A multivitamin supplement should be offered at least weekly.

REPRODUCTION

Males court females with head-bobbing and throat-puffing displays. Females lay 1–2 pea-sized eggs, usually glued to a secure surface, approximately 2–3 weeks after mating. Eggs hatch between 60 and 90 days depending on incubation temperature. When left in the enclosure with natural night-time fluctuations, hatching may occur after around 100 days. Hatchlings are extremely small and should be transferred immediately to a separate enclosure.



Raising hatchlings can be challenging, with failure to thrive commonly reported. Successful rearing depends on optimal UV exposure, basking opportunities high in the canopy (for example under a T5 UV tube), adequate warmth, high humidity and excellent ventilation. Frequent misting is crucial. Hatchlings should be offered fruit flies, pinhead crickets and supplemented day gecko feeding powders. Mashed banana may be used during the first week. Daily calcium supplementation is essential.