Setting up UVB questions

[Caitlin]

I'm not aware of any studies that show this for Python regius, though I don't have access to academic databases. Google Scholar links to only two studies, one showing that they do not manufacture endogenous D3, and another that was a clinical discussion of severe damage caused by a faulty lamp (relevant again in light of the new wave of UVB LEDs hitting the market, most marketed by no-name foreign companies).

Could you provide links or citations to this science regarding ball pythons?

Sure! Though there are also several reasons other than serum D3 production to support providing UVB to snakes. I'll admit that I tend to be research and data-driven, but I am super reluctant to turn this thread into a list of citations. I'm glad to share other citations in a separate thread if anyone is interested! Since your question is on the serum D3 research, I'll gladly share some links here and will leave the rest to a potential separate thread if anyone wants that. I just don't want to push citations on folks rather than have a conversation, you know?

There were methodological issues with the study by Hedley and Eatwell that you linked. And it should be noted that this is the ONLY study ever done on snakes that failed to show an increase in serum D3 after UVB exposure. Dr. Hedley herself has stated that the sample group size was too small and that the controls were not at all ideal. The experimental group was 100% female and started off with very high serum levels of D3 in the first place due to breeding season, when they are pumping out D3 for egg production. There was no way of determining how much D3 they were receiving in their diet, and for those two reasons, there's the very real possibility that they had no need at all to be producing endogenous D3 at the time of the study. So of course the end result would be that the snakes were not producing D3 after UVB exposure. They weren't producing it because they already had enough, and didn't need to produce more.

The control group was mostly males, with much lower serum D3 levels naturally - so the two groups can't really be compared. But I want to emphasize that Drs. Hedley and Eatwell did a good job with the study given the limitations imposed in the UK on doing this sort of research. It's just that the study can't really be used to support or debunk the idea that UVB exposure is important for Ball Pythons for D3.

Here's a list I cut/paste from a saved document that includes a list of citations for studies on multiple other snakes. Just to compare: Corn snakes, which are used in many of the studies cited below and which are shown to benefit from UVB, actually require a lower UV level than Ball Pythons. Corn snakes inhabit Ferguson zone 1 (crepuscular shade dwellers) as opposed to Ball Pythons which inhabit Ferguson zone 2 (partial baskers).

Experiments on Corn Snakes, Burmese pythons, Jamaican boas and others have shown a drastic increase in serum D3 levels after basking under UV:
Acierno, Mark J., et al. "Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata)." American journal of veterinary research 69.2 (2008): 294-297.

Bradwell, Jordan, and Jessica Hackett. "The Effects of Ultraviolet (UV) Light Exposure on the Physiology And Behaviour of Captive Corn Snakes (Elaphe guttata)." RATEL (2013): 9.

Nail, Student-Abigail. "Does exposure to UVB light influence the growth rates and behaviour of Corn Snakes, Pantherophis guttatus?” BI6154–Dissertation at Reaseheath College.

Bellamy, T. and Stephen, I. (2007) The Effect of Ultrviolet B (UVB) Illumination and Vitamin D3 on the Activity, Behaviour and Growth Rate of Juvenile Jamaican Boas Epicrates subflavus, received through personal communications with F. Baines author of www.UVguide.co.uk

Artificial ultraviolet b radiation raises plasma 25-hydroxyvitamin d3 concentrations in Burmese pythons (Python bivittatus)." Journal of Zoo and Wildlife Medicine 49.3 (2018): 810-812.

UV has even been found to be one of the factors that determine niche partitioning between conspecific species of snake, for example:

Brinker, Andrew Michael. "An ultraviolet light survey of three species of semi-aquatic snakes at the Old Sabine Bottom Wildlife Management Area, with intraorder comparisons and microhabitat descriptions [electronic resource]." UMI thesis. (2006).