Licht-im-Terrarium: Literaturdatenbank
Licht-im-Terrarium: Literaturdatenbank |
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Nail, A. (2011). Does exposure to uvb light influence the growth rates and behaviour of hatchling corn snakes, pantherophis guttatus? Unpublished BSc Dissertation, Reaseheath College in collaboration with the University Of Chester. Added by: Sarina (2020-01-13 10:22:10) Last edited by: Sarina (2024-11-26 10:22:20) |
| Resource type: Thesis/Dissertation BibTeX citation key: Nail2011 View all bibliographic details  |
Categories: Englisch = English Keywords: Schlangen = Snakes, Ultraviolett = Ultraviolet Creators: Nail, Palmer Publisher: Reaseheath College in collaboration with the University Of Chester |
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Meine Sichtweise (Keine vollständige Zusammenfassung des Artikels! Meine Meinung muss nicht mit der Meinung der Autoren übereinstimmen! Bitte lesen Sie auch die Originalarbeit!)
12 snakes were divided in 3 groups, Each snake housed individually in Exo Terra 12"-square faunariums with a T8 18 W fluorescent tube above the mesh (one tube for two faunariums). Light was on 12 hours per day. (1) Arcadia Natural Sunlight 2% UVB, UV-Index 0.5 Graph 4.2: The snakes in the 2% UVB group had the lowest weight, no UVB had the heighest weight. This "nonlinear" distribution to me indicades UVB had no influence, even though the Spearman's rank correlation test found a significant influence. The active movement (AM) behaviour was significantly more frequenently in the 2% UVB group, but not different in the 6% and the 0% UVB groups.
Added by: Sarina Last edited by: Sarina |
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The benefit of UV light for reptiles is a long, much debated area and results and opinions are often mixed. To investigate the growth and behaviour effects of UVB exposure on Pantherophis guttatus, twelve snakes were used. These were split into three groups of four snakes, and exposed to different levels of UVB; 2% UVB (1), 6% UVB (2) and a control group (3). Due to health reasons, two snakes had to be removed from group 2, therefore number of participants was: group 1 – four snakes, group 2 – two snakes, group 3 – four snakes. Results showed no significant difference in growth for snake length. However, a significant difference was noted in snake weight between groups 1 and 3, the potential reasons for which are discussed. No significant difference was found in basking high, however a significant difference was observed in basking medium (the best position for UVB exposure) between groups 1 and 2. The control group was observed more times than group 1 in this behaviour, perhaps in attempts to access UVB, although this was not statistically significant. Again, the potential reasons for this behaviour are discussed. Group 1 were observed significantly more actively moving than group 2, and also group 3, but this was not statistically significant. Group 1 were observed in the UVB basking area on level 3 considerably more times than group 2, but only slightly more than group 3; 39%, 8% and 35% respectively. P. guttatus are known to be able to synthesis vitamin D3 through exposure to UVB and this may also influence other metabolic processes in this species. This study shows that P. guttatus will voluntarily expose themselves to UVB, the effects of which can increase activity levels. This increase in activity levels may be due to the possible influence of UVB on metabolic processes. Therefore, a low level of UVB, such as a 2% bulb, can be provided to P. guttatus without detriment.
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Kritik von Rainer Breitling:
Secondly, in an unpublished undergraduate thesis, Nail [2011] purports to show behaviour and growth differences in corn snakes resulting from different levels of UV exposure, reporting a “statistically significant” increase in activity at moderate levels of UV lighting. Unfortunately, these results do not withstand scrutiny: the claimed statistical significance is merely the result of an extreme pseudoreplication issue (Hurlbert 2009), i.e. repeated observations on the same very few animals are treated statistically as if they represented independent experiments. This is a serious mistake, and the statistical conclusions are consequently fatally flawed. If one has a closer look at the actual data shown in the figures of the thesis, one can clearly see in that the UV exposure makes no difference to any of the behavioural characteristics measured. There is no evidence whatsoever to support the conclusion that “UVB light … has a positive effect on [corn snake] activity levels”. The only marginal effect that can be discerned is in the opposite direction of what had been predicted: without UVB, the animals grow faster than with UVB (Nail 2011:Fig 4.2). This “effect” is not statistically significant, but it is important to note that it is the opposite of what advocates of UV lighting for snakes would have expected. The most forcefully stated conclusion, “that snakes will voluntarily expose themselves to UVB light”, is entirely fanciful: none of the experimental animals was offered any choice between different light sources. Added by: Sarina Last edited by: Sarina |