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Investigating Body Condition, Autotomy, and the Blue-spotted morph in Slow-worms (Anguis fragilis) in Jersey Populations: Habitat, Intersex and Ontogenetic Variation


The Slow worm is one of the most abundant species of reptile in Western Europe. However, due to its cryptic nature there are considerable gaps within the knowledge surrounding it. We investigated the ecological determinates of body condition, caudal autotomy, and blue spotted frequency in the European slow worm (Anguis fragilis), in an insular location, Jersey (The Channel Islands). We assessed whether habitat, year, ontogeny, and sex affect body condition, caudal autotomy, and blue spotted frequency. We also evaluated the effects of autotomy on body condition, by comparing occurrence, estimate tail loss (%) and break index, proximal (> 50% of tail loss) vs distal (≤ 50% tail loss). We found that tail autotomy occurred in the majority (64.92%) of individuals, correlated with size, therefore age, and males displaying significantly higher occurrences than female conspecifics. Autotomy rates were lower in suburban habitat (amenity grassland) than wild sites, likely resulting from decrease predation pressure and with autotomy occurrence. Individuals that display distal breaks are likely to have higher body condition than those with proximal breaks. We also observed that body condition was highest in juvenile individuals, likely driven by lower energy expenditure. Body condition decreased between years, which may be driven by environmental effects. Only mature males displayed occurrence of blue spotting, we could not indicate any ecological determinants for the frequency. Our results suggest there are multifaceted drivers for the mentioned physiological characteristics that need to be explored further.

Categories Ecology, Island studies
Keywords Autotomy, habitat, Ontogenetic, reptile, Slowworm, variation
Author S Napaul
Date published 2023
Document type Master’s Dissertation
Organisation Jersey International Centre for Advanced Studies
IRR Code IRR/JICAS/2023.43594
Funder Ecology Trust Fund
File Type pdf