Licht-im-Terrarium: Literaturdatenbank

Reptiles are a diverse group Of around 1 1700 extant species. 450 Of Which are housed zoological collections (Uetz 2022). Approximately eight million reptiles are kept privately in the European Union (Toland et al 2020). Broad spectrum lighting (fig. 1), Which includes ultraviolet (UV) radiation and Visible light, is required to maintain reptile health and wellbeing. UVA is Visible to tetrachromatic species and influences photoperiod, while UVB, when combined With infrared radiation (IR), facilitates Vitamin D, synthesis. Which is vital for the regulation Of Calcium (Baines 2016).

Reptiles commonly suffer from hypovitaminosis D. Which a major cause Of metabolic bone disease (MBD). Although dietary supplementation is often used to moderate vitamin D levels, hypervitaminosis D may occur. Conversely. vitamin D absorbed from UV is converted into inert photoproducts. making this form Of exposure Safer than supplementation (Oonincx et 2020). Therefore, Close replication the Sun/s radiation is a challenge Of modern herpetoculture (Hamilton et 2022).

Aims & Objectives
• Identify any preferences displayed by a captive lizard to a range of artificial light sources
•Compare basking spot dwell times across a range of light pairings

Hypothesis
• H0: will not be a statistically significant difference between dwell times under different light
• H1: There will be a statistically sign incant difference between times under different artificial Light sources.

Literature Review
Reptiles represent around 11% of terrestrial vertebrates housed in captivity (Conde et 2013), appear in 3% of Welfare Publications (Binding et al» 2020). Only One Study was identified which Concentrated On reptile lighting preferences (Dickinson and Fa. 1997), That Study found a significant Preference to incandescent bulbs over UV and non-light emitting heat sources. A Small sample Size and relatedness of individuals were limiting factors. Additionally, technological developments may lead to alternate results in a reproduced Study using modern equipment.

Due to insufficient data it was necessary to consider alternative taxa, Preference studies in birds were numerous, due in part to greater sample sizes. Birds are a suitable alternative to reptiles due to shared tetrachromatic vision (Rana et al., 2021). The majority of studies suggested a significant Preference UV and greater LUX over non-UV emitting light sources and Iower LUX (Liu et al. 2018; Raccoursier et al, 2019: Rana et 2021)

Methods
A Study enclosure was set up With two basking Sites and a neutral hide (fig. 3). A dome, LED bar and UV tube was secured above each basking Site. A range Of commonly used bulbs were Selected (fig. 4). Light sources Were then arranged into 8 configurations and these were randomly organised into 28 test Pairings. For each pair. a three hour time budget Study was completed using continuous sampling. Time spent by subject (fig. 2) on and off each basking Site and in the neutral zone Was recorded.

Results
Comparisons between the time spent directly on each basking spot revealed no significant difference between any configuration (Fig 5) (Kruskal-Wallis Hz=2.11, p=0.954)
The largest time spent in the neutral zone was during the BC pairing which was a mercury vapour and jungle dawn LED bar vs halogen and T5 UVB tube. This was 4593 seconds (fig. 6).

The subject spent more time 'off basking' than 'On basking' during eight Pairings (28.57%) (fig. 7). Of these three were 'off basking' under deep heat projector, UV tube and LED bar (37.5%). Two were 'off-basking' under deep heat projector and UV tube (25%). In total, five out of eight pairings were 'off basking' was favoured over 'on basking' were deep heat projectors (62.5%)

Discussion

The Study found no significant Preference between different lighting configurations. contradicting previous research (Dickinson and Fa. 1997). The absence of significance may be due to consistent surface temperature and UV index at each basking Site, reducing confounding variables. The provision of LED lighting did not have a measured effect on basking times, possibly due to stress caused by unfamiliar lighting and lack of experience with broad spectrum lighting (Morgan and Tromboræ 2007; Fischer and Romero. 2019). This is supported by increased locomotor latency and higher neutral Zone dwell times during the first pairing With LED lighting. Increasing the acclimatization period could mitigate stress responses (Rana 2021). Additionally, this Study was limited by a Small sample Size

The lack of a significant preference in this Study could suggest that providing multiple basking Spots may have a positive correlation with reptile welfare, as it promotes exploratory behaviour, because similar time was spent on each basking site. Future studies could include the use of a light source which is moved across the enclosure to match the species' photoperiod. Which may trigger more natural thermoregulatory behaviours in captivity. A more appropriate research question may be "does the provision of multiple basking Sites have a measurable effect on reptile behaviour?" (Haines. 2013: Noble et al. 2012; Oonincx and van Leeuwen. 20! 7; Warwick et 2013)

Conclusion
Herpetoculture research is lacking due to reptiles being less charismatic than other animals. Yet it is crucial to improve knowledge to improve welfare. Reptiles require access to broad-spectrum lighting that mimics their natural habitat to thrive in captivity and avoid conditions like MBD, While reptile preference studies are limited, lizards can distinguish and choose between light sources, providing insight into ideal parameters for each species. The Study found no significant preference but may have identified positive behaviour. The methodology could be adapted for more data collection With fewer light options. Collaborating With BIAZA institutions could increase sample Size for a robust database of reptile light preference.