Background The movement and spatial ecology of an animal depends on its morphological and functional adaptations to its environment. In fossorial animals, adaptations to the underground life help to face peculiar ecological challenges, very different from those of epigeal species, but may constrain their movement ability. Methods We made a long-term capture-recapture study of the strictly fossorial amphisbaenian reptile Trogonophis wiegmanni to analyze its long-term movement patterns. We also used passive integrated transponder (PIT) telemetry to detect and follow undisturbed individuals underground, obtaining data of their short-term movement patterns. Results Amphisbaenians showed a high site fidelity, moving short distances and over small areas, and spending some days without any noticeable movement, even under favorable conditions. We also found differences in movements between sexes and age classes. Conclusions This movement and spatial strategy can be related to the energetic constrains of underground burrowing, or to the low metabolic requirements of fossorial reptiles, as distances and areas covered were much smaller than for epigeal reptiles of similar size. Individual differences probably reflect differential reproductive and social requirements of males and females, and that younger individuals might show more floating behavior until they can settle in a territory. This study is a rare example describing the movement ecology of a fossorial species and may contribute to the general understanding of the factors that affect space use and movement decisions in animals.
Melanin is the basis of coloration in many animals, and although it is often used in communication, thermoregualtion or camouflage, melanin has many other physiological functions. For example, in polluted habitats, melanin can have a detoxifying function.Melanic coloration would help to sequester in the skin the heavy metals contaminants from inside the body, which will be expulsed to the exterior when the skin is sloughed. Moreover, animals should have evolved more melanic colorations in more polluted habitats ("industrial melanism" hypothesis). We examined whether the fossorial amphisbaenian reptile, Trogonophis wiegmanni, is able to eliminate heavy metals, derived from soil pollution by seagulls depositions, through sloughing its skin. Our results suggest a covariation between levels of soil pollution by heavy metals and the concentration of heavy metals in the sloughed skins of amphisbaenians. This suggests that amphisbaenians may expel heavy metals from their bodies when they slough the skins. We also tested whether amphisbaenians inhabiting soils with higher levels of heavy metal pollution had darker (melanin-dependent) body colorations. However, contrary to predictions from the "industrial melanization" hypothesis, we found a negative relationship between soil pollution and proportions of melanic coloration. This contradictory result could, however, be explained because heavy metals have endocrine disruption effects that increase physiological stress, and higher stress levels could result in decreased melanogenesis. We suggest that although amphisbaenians might have some detoxifying mechanism linked to melanin in the skin, this process might be negatively affected by stress and result ineffective under conditions of high soil pollution.
Animals often face situations that require quantity discrimination for decision-making.Differentiating between more and less amounts might be adaptative in different contexts such as in social relationships, navigation, or foraging. However, feeding close to conspecifics might change foraging behavior decisions due to changes in predation risk perception and competition for resources. Here, we tested quantity judgement abilities of foraging rock lizards (Iberolacerta cyreni) in a spontaneous choice test between 5 versus 10 cricket prey. Lizards tested had been previously housed alone or in a group to examine how social experience affected foraging decisions. Our results showed that 'Grouped' lizards had greater foraging activity than 'Solitary' lizards. Furthermore, all lizards demonstrated some ability to discriminate between the two amounts of prey.These results reveal the capability of quantity judgments in rock lizards and also that foraging decisions may be modulated by the previous social experience. Significance statementThe presence of food sources differing in quantity, together with the proximity of conspecifics can strongly affect foraging decisions. Previous studies showed various levels of quantitative abilities on different taxa, but results with reptiles are scarce and inconsistent. On the other hand, previous research showed that grouping may have a notable effect on foraging behavior. Here, we demonstrate that male rock lizards can discriminate between two amounts of prey and that there is an effect of the previous -4social experience on foraging behavior, as lizards that had been housed alone showed less interactivity with food. These outcomes reveal the existence of quantitative abilities in lizards and the importance of the previous social experience in foraging decisions.
To understand wildlife responses to the changing environment, it is useful to examine their physiological responses and particularly their endocrine status. Here, we validated an enzyme immunoassay (EIA) to non-invasively quantify fecal corticosterone metabolites (FCM) in the fossorial amphisbaenian reptile Trogonophis wiegmanni from North Africa. We supplemented animals assigned to the treatment group with corticosterone dissolved in oil applied non-invasively on the skin for several days, while control groups received the oil-alone solution. Fresh feces were collected at the end of the supplementation period, and FCM levels were quantified by an EIA. Basal FCM levels were similar for both treatments and increased at the end of the test, but FCM increased significantly more in corticosterone-treated animals. A further examination of FCM levels in a wild population of this amphisbaenian did not find overall sexual, size or seasonal differences but showed a high range of variation among individuals. This suggests that different uncontrolled intrinsic or local environmental variables might increase the circulating glucocorticoid levels of different individuals. Our results confirmed the suitability of EIA for analyzing physiological changes in FCM in this amphisbaenian species. This technique may be useful for understanding and remediating the little-explored potential stressors of the soil environment that may negatively affect the health state of fossorial reptiles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.