Delicate Garden Skink

Appearance

The delicate skink is more common in suburban gardens than in adjacent native bushland. It has a moderate body with a medium length, slender tail. Its scales are smooth. The back and sides are greyish-brown to rich brown, often with darker and paler flecks. A narrow yellowish-brown stripe is usually present on the outer edge of the back. The species can also have two distinct forms: a prominent white stripe and a less prominent white stripe. This dimorphism is not strictly distinguished by gender.

Distribution

"Lampropholis delicata" is a skink of the subfamily Lygosominae, originally from Eastern Australia. Accidentally introduced and invasive in New Zealand, Hawaii, and Lord Howe Island.

Habitat

Experimental evidence suggests that "L. delicata" prefer leaf litters to bare substrate, with more nuanced preferences for different types of leaves, as they adjust the structure, depth, and distribution of their litter layer accordingly. Generally, these lizards select more open structures. Such open structure makes thermoregulation more effective, as lizard individuals can move into different positions within their habitat to avoid overheating or raise their temperature to more optimal levels. Achieving optimum temperature levels influences their efficiency in avoiding predators and capturing prey, thus making open habitats conducive to many other behavioral characteristics. Furthermore, open litters allow for more effective foraging movements and also provide lizards with more access points and space to move, which is necessary when accessing refuge for predator avoidance. The abundance of "L. delicata" in an area may also be influenced by habitat modifications that vary the structure of their litter layers.

Reproduction

Although the biological mechanisms of reproductive cycles between male and female "L. delicata" lizards differ, they align seasonally such that mating can occur in the late summer. Typically, these lizards produce a single clutch per year of about two to four eggs. In a study analyzing the reproductive cycles in male and female "L. delicata" over a two-year period, it has been found that, in males, the testes contain very few mature sperm during the late autumn and winter months, and during this period, spermatogonia are predominantly present as germ cells while the seminiferous tubules are at their smallest in diameter. However, spermatogenesis begins during the early spring months, allowing for the development of primary and secondary spermatocytes. Nearing the end of September, mature sperm will pack the now expanded seminiferous tubules, and the sperm will deplete during the months of October and November. In the summer, a second wave of spermatogenesis persists to produce more mature sperm during February, which depletes from the seminiferous tubules in spring and then again during autumn presumably for mating reasons, although only mating during the late summer has been observed.

In females, the autumn and winter months between February and July are defined by quiescent ovaries, and only during the late winter and spring months between August and October, follicles begin growing into notable sizes. In October or November, one or two follicles per ovary become vitellogenic and ovulated. After ovulation, the corpora lutea forms and maintains until oviposition occurs about a month later. Following ovulation, many other growing follicles become vitellogenic, although they may not ovulate and may regress after the mating period during the late summer. In females, many of these ovarian events parallel ovarian weights.

Although growing oocytes are not commonly found in young adult females, young adult males of all ages undergo spermatogenesis. Observation of "L. delicata" suggests that they produce no more than one clutch per season; however, some evidence suggests that young female lizards may produce a clutch in the season following their birth, which aligns with male lizards’ ability to mate during both the spring and late summer. Though temperature and photoperiod are hypothesized to induce reproductive activity in lizards, more evidence suggests the influence of rain patterns on lizard reproduction cycles. With lower annual rainfall, annual vegetation productivity, and arthropod availability, food becomes relatively scarce for these lizards. As a result, it may influence the follicular development in female lizards, in particular the vitellogenesis cycle, although decreased rainfall may be insufficient to influence male testicular patterns.

Female "Lampropholis delicata" lizards tend to reproduce in the spring and summer seasons. It was found that there is a positive relationship between body size and clutch size. Clutch size typically ranges between 1 and 7. Communal egg nests are common.

Food

"Lampropholis delicata" can be classified as diurnal, terrestrial, arthropod feeders, and they consume a wide range of prey. An in depth analysis of "L. delicata" gut samples—taken from their foregut, hindgut, and stomach—reveals the wide variety of prey taxa and size classes incorporated into their diets. These gut samples are taken from "L. delicata" that reside in the Mumbulla State Forest, a region with a vast history of fires and logging. As a result of intense fires, several canopies and ground vegetation have ceased to sustain the lizard population, resulting in a primarily carnivorous diet. "L. delicata" primarily consumes spiders, insects, snails, and crustaceans. Gut analysis after a major fire in 1980 reveals that these lizards ate limited amounts of invertebrates, and they had a preference for bees, wasps, and springtails over beetles, termites, and ants relative to their related species "L. guichenoti", which also reside in the Mumbulla State Forest.

"L. delicata" are characterized as general feeders, and their prey can be described as aerial and arboreal, slow-moving, concentrated, concealed, and active. These lizards demonstrate foraging behavior and employ “active foraging” and “sit-and-wait” strategies to capture their prey. Because their environment is prone to fires and droughts, "L. delicata" have adapted flexibility into their foraging ecology. They practice opportunistic foraging in that they consume a wide variety of prey and adapt to whatever food becomes available, rather than following a foraging pattern and consuming similar prey. As a result of droughts, arthropods become less abundant; however, "L. delicata" are not dependent on resident invertebrates, like those that reside in litters, and instead forage after a broader range of insects spanning both aerial-arboreal invertebrates and ground-dwelling invertebrates.