Search

Aim: Squamate fitness is affected by body temperature, which in turn is influenced by environmental temperatures and, in many species, by exposure to solar radiation. The biophysical drivers of body temperature have been widely studied, but we lack an integrative synthesis of actual body temperatures experienced in the field, and their relationships to environmental temperatures, across phylogeny, behaviour and climate. Location: Global (25 countries on six continents). Taxa: Squamates (210 species, representing 25 families). Methods: We measured the body temperatures of 20,231 individuals of squamates in the field while they were active. We examined how body temperatures vary with substrate and air temperatures across taxa, climates and behaviours (basking and diel activity). Results: Heliothermic lizards had the highest body temperatures. Their body temperatures were the most weakly correlated with substrate and air temperatures. Body temperatures of non‐heliothermic diurnal lizards were similar to heliotherms in relation to air temperature, but similar to nocturnal species in relation to substrate temperatures. The correlation of body temperature with air and substrate temperatures was stronger in diurnal snakes and non‐heliothermic lizards than in heliotherms. Body‐substrate and body‐air temperature correlations varied with mean annual temperatures in all diurnal squamates, especially in heliotherms. Thermal relations vary with behaviour (heliothermy, nocturnality) in cold climates but converge towards the same relation in warm climates. Non‐heliotherms and nocturnal species body temperatures are better explained by substrate temperature than by air temperature. Body temperature distributions become left‐skewed in warmer‐bodied species, especially in colder climates. Main Conclusions: Squamate body temperatures, their frequency distributions and their relation to environmental temperature, are globally influenced by behavioural and climatic factors. For all temperatures and climates, heliothermic species' body temperatures are consistently higher and more stable than in other species, but in regions with warmer climate these differences become less pronounced. A comparable variation was found in non‐heliotherms, but in not nocturnal species whose body temperatures were similar to air and substrate irrespective of the macroclimatic context. [ABSTRACT FROM AUTHOR]

High-latitude lizards live in environments where ambient air temperature at night is frequently below retreat temperatures, which likely has implications for nocturnal emergence and activity. However, patterns of lizard activity at night under current temperate climates are poorly understood, a situation that limits our understanding of potential effects of climate change. We investigated patterns of nocturnal emergence and activity in the cold-adapted, viviparous gecko (Woodworthia 'Otago/Southland'). We measured operative environmental temperature (T e) available to geckos that emerged at night and simultaneously assessed nighttime emergence activity using time-lapse trail cameras. Also, we assessed field body temperature (T b) of emerged geckos of various life history groups at night using thermography to understand how current weather conditions affect field T b of emerged geckos. Our results show that Te , nocturnal emergence activity and field-active T b increased with nighttime air temperature. Nocturnal emergence was highest in spring and summer but also occurred in autumn and (unexpectedly) in winter. Geckos were active over a broad range of T b down to 1.4°C (a new record low for lizards) and on rock surfaces typically warmer than air temperature or T b. We conclude that this nocturnal, high-latitude lizard from the temperate zone is capable of activity at low winter temperatures, but that current climate limits emergence and activity at least in autumn and winter. Activity levels for cool-temperate reptiles will probably increase initially as climates warm, but the consequences of increased nocturnal activity under climate change will probably depend on how climate change affects predator populations as well as the focal species' biology. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are on the rise around the world and have become some of the leading causes of death. To enhance their chances of survival and effectively manage costs, indigenous communities in developing countries have sought natural remedies from plants and food materials within their reach. This established preference has seen Moringa oleifera garner special attention due to the praised effects of its leaves and other parts. The focus of this study was to investigate the antihypertensive activity of crude MoMLE (CME) and five solvent fractions of the same using C. gambianus and elucidate the effect of their separate interactions with atropine. Moringa oleifera (MO) leaf was collected from the University of Nigeria, Nsukka; C. gambianus was obtained from Okposi-Okwu, Ebonyi State; and antihypertensive activity was assessed using a blood pressure transducer following established methods. The result showed that CME and other fractions had a dose-dependent negative inotropic and chronotropic effect on C. gambianus as follows: N-Hexane fraction (NHF)-19.0 8.1 mmHg, chloroform fraction (CLF)-15.0 3.0 mmHg, ethyl acetate fraction (EAF)-22.3 10.7 mmHg, acetone fraction (ACF)-19.7 7.2 mmHg, and methanol fraction (MEF)-25.7 1.2 mmHg. Similar activity was observed for acetylcholine (-42 ± 4.4 mmHg) which was used as a reference drug (positive control). The study revealed that MoMLE has a hypotensive effect with methanol fraction (MEF) having the second highest hypotensive (-25.7 ± 1.2 mmHg) activity after CME with a 28.7 ± 4.2 mmHg lowering effect. Atropine interaction blocked the extracts as well as acetylcholine, suggesting a muscarinicreceptor mediated action. [ABSTRACT FROM AUTHOR]

Studies of thermal sensitivity in ectotherms require accurate measurements of body temperature using a reliable device, including in field situations. In this study, we tested the accuracy of a compact and inexpensive mini-infrared thermometer (mini-IRT, 22.3 g) at close distance (within 5 mm) for measuring skin surface temperature of small lizards or their models (painted copper bars). First, we used copper bars to assess the effect of model width on the accuracy of the measurement. We placed the heated models on a cool background, and then surface temperatures were measured with a mini-IRT for comparison with a thermogram from an infrared camera (IRC). We also assessed the accuracy of the mini-IRT for measuring skin temperature for two species of small lizards in the laboratory and in the field, in comparison with the skin surface temperature measured with the IRC and with cloacal temperature measured with a thermocouple thermometer. Our results with inanimate models show that the accuracy of the mini-IRT at a distance within 5 mm is biologically acceptable (within ±1.0 °C of the mean value obtained using a more expensive, calibrated device) when the width is ≥ 7 mm. For live lizards, we observed highly significant relationships between skin surface temperature measured with the mini-IRT and temperatures measured with the two other devices. The mean discrepancies between the mini-IRT and other devices were acceptably small for geckos but larger for the smaller and more slender skinks. Taken together, our results suggest that skin temperature measured with the mini-IRT at a close distance is acceptable for field studies on lizards with an abdominal width ≥7 mm, serving as an inexpensive proxy for core body temperature in situations where portability and affordability of equipment and minimal animal handling are paramount. Nonetheless, calibration of mini-IRTs before use is strongly recommended. • A pocket-sized infrared thermometer (mini-IRT, 22.3 g) is an inexpensive field tool. • Mini-IRT values matched means for an infrared camera with models of width ≥5 mm. • Temperature discrepancies between devices were minor for live geckos, but larger for small skinks. • The mini-IRT is useful for measuring skin temperature of lizards when abdominal width ≥ 7 mm. • Calibration of mini-IRTs before use is strongly recommended. [ABSTRACT FROM AUTHOR]

The survival of land snails in an adverse environmental condition depends on the integral physiological, morphological and behavioural adaptations. These adaptations are essential in understanding the species-specific habitat requirements and in predicting their environmental responses. In this study, the monthly and the periodic patterns of eco-physiological adaptation of land snail, Achatina achatina in Nsukka tropical agro-ecosystem were assessed from December 2012 to July 2013. Standard methods were employed in sampling the land snail and determination of the water content, biochemical fuel reserves and enzyme concentrations of the samples. The present results showed that lipids were high at the beginning of aestivation and depleted as the aestivation progressed. Glycogen was significantly low throughout the aestivation months (December–March) and increased in the active months (April–July). Protein content recorded a definite pattern all through the months studied. Catabolism of lactate and a decrease in activity of LDH during aestivation and substantial increase upon activation were observed. Data showed that transaminase and aspartate enzymes depleted during the aestivation months indicating that the snails may have developed potential cell injury due to oxidative stress and thermal heat. A disassociation between the physiological responses and climatic data was recorded. The physiological adaptation of A. achatina ensures regular adjustment under extreme conditions and compensates for its metabolic regulation in the tropics. It is concluded that survival of A. achatina is not environmentally predicted; rather it depends on the species-specific inherent process in predicting responses for survival. [ABSTRACT FROM AUTHOR]

Rocky retreats are limited and geologically constrained resources for rock-dwelling nocturnal lizards. Such lizards should seek retreats that offer thermoregulatory benefits without the risk of overheating during the day, and that protect from predation. For cold-adapted species where air temperature is frequently lower than optimum temperature for performance, factors influencing retreat-site selection and whether future warmer conditions will force superficial rock slabs to be abandoned on hot days remain poorly known. Here, we predicted that retreats selected by a nocturnally foraging, cool-temperate gecko from southern New Zealand would be thermally heterogeneous and that future warmer temperature will force lizards to abandon daytime retreats on hot days. We sampled loose rock slabs (potential retreats) in a tussock-grassland site in all seasons. We measured seasonal rock temperature profiles and field body temperature (T b) of captured geckos using thermography and quantified the physical characteristics of each potential retreat. We found that both physical characteristics and rock temperatures determine choice of retreats. Field T b of lizards positively correlated with retreat and air temperatures. Also, retreat temperatures, including those of the substrate below the rock slabs, showed complex heterogeneity enabling lizards to choose microsites within retreats to achieve preferred body temperatures intermittently. Observed seasonal shifts in characteristics of occupied rocks imply that lizards choose retreats to maximise warmth in spring, minimise risk of overheating (remain below voluntary thermal maximum, VT max) in summer and avoid freezing over winter. Our study demonstrates the importance of microclimatic conditions in influencing retreat-site selection. Climate warming might lead to seasonal changes in use of rock slabs and possibly be beneficial initially, but longer-term implications need to be examined. • Complex thermal heterogeneity exists on the occupied rock slabs. • Retreat temperatures presently are often below lizards' preferred body temperature. • Lizards select retreats to maximise warmth in spring, minimise the risk of overheating in summer and avoid freezing in winter. • Seasonal shifts in retreat selection will buffer the risk of overheating under superficial rock slabs. • Cool-temperate lizards may derive thermal benefits initially from future climate warming. [ABSTRACT FROM AUTHOR]

Previous study using the traditional method of screening snails for infection reported shedding of Schistosoma cercaria by Biomphalaria snails from a river in Nkalagu, southeastern Nigeria. This is contrary to published reports that Biomphalaria from this part of the country does not shed schistosome cercaria. Here, we employed the use of polymerase chain reaction (PCR) methods to screen and characterize the Biomphalaria snails from Nkalagu. Snails were collected from the River Uzuru in dry season, identified and subjected to molecular assays. Genomic DNA (gDNA) was extracted from whole tissues of the 212 Biomphalaria snails and amplified using conventional PCR to check for the schistosome infection level. Assay for the detection of S. mansoni infection was further done using a nested PCR (nPCR). We amplified the entire internal transcribed spacer 2 (ITS2) regions from gDNA of the 212 snails. The representative samples were sequenced and subjected to BLAST searches to confirm snail species. Of the 212 snails screened, 164 (77.4%) of the snails were infected with schistosomes, but only 16 (9.76%) of the snails were positive for S. mansoni infection. Amplification of the snails' ITS2 region yielded a product of 460 bp, and BLAST searches confirmed the snails to be B. pfeifferi , and BLAST searches confirmed the snails to be B. pfeifferi. This paper reports for the first time the presence of S. mansoni positive B. pfeifferi in Nkalagu, which suggest there may be cases of intestinal schistosomiasis in this part of Nigeria. [ABSTRACT FROM AUTHOR]

Understanding the interaction between upper voluntary thermal limit (VT max ) and water loss may aid in predicting responses of ectotherms to increasing temperatures within microhabitats. However, the temperature at which climate heating will force cool-climate nocturnal lizards to abandon daytime retreats remains poorly understood. Here, we developed a new laboratory protocol for determining VT max in the retreat-dwelling, viviparous Woodworthia 'Otago/Southland' gecko, based on escape behaviour (abandonment of heated retreat). We compared the body temperature ( T b ) at VT max , and duration of heating, between two source groups with different thermal histories, and among three reproductive groups. We also examined continuous changes in T b (via an attached biologger) and total evaporative water loss (EWL) during heating. In the field, we measured T b and microhabitat thermal profiles to establish whether geckos reach VT max in nature. We found that VT max and duration of heating varied between source groups (and thus potentially with prior thermal experience), but not among reproductive groups. Moreover, geckos reached a peak temperature slightly higher than VT max before abandoning the retreat. Total EWL increased with increasing VT max and with the duration of heating. In the field, pregnant geckos with attached biologgers reached VT max temperature, and temperatures of some separately monitored microhabitats exceeded VT max in hot weather implying that some retreats must be abandoned to avoid overheating. Our results suggest that cool-climate nocturnal lizards that inhabit daytime retreats may abandon retreats more frequently if climate warming persists, implying a trade-off between retention of originally occupied shelter and ongoing water loss due to overheating., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

Background: The fruit extract of Dacryodes edulis (D. edulis) , the African pear or plum, a tree indigenous to the humid tropics has been used for managing wounds, skin diseases, sickle cell anaemia, dysentery and fever in some African nations. In South Eastern Nigeria, 'herbal doctors' include its marshed fruit in decoctions administered to diabetic patients. However no scientific substantiation of their claim and use exist in literature. Hence, the need to evaluate the antidiabetic and hypolipidaemic activity of hexane extracts of D. edulis fruit in alloxanised animal model., Materials and Methods: Sub-toxic doses between 400 and 1600mg/kg were orally administered sub-chronically to alloxan-induced diabetic rats for 15 days and compared to glibenclamide (2.5mg/kg). The glycaemia levels, body weights, lipid profile, blood urea, creatinine and liver enzyme levels were measured. Basic histology of the pancreatic tissue was also performed to examine the effects on the pancreas as possible mechanistic lead., Results: Oral acute dosing of D. edulis hexane extract decreased blood glucose levels, while sub-chronic treatment of the extract down-regulated significantly hyperglycaemia, total cholesterol, triglycerides, LDL-C, ALT and ALP levels. However, the HDL-C levels increased significantly. Histopathological examination of the pancreatic tissues after sub-chronic treatment showed that glibenclamide and the highest dose of the extract 1600mg/kg restored the afore-damaged pancreatic β-cell architecture., Conclusion: Our findings portend that D. edulis hexane fruit extract possesses hypoglycaemic and hypolipidaemic activities as well as restoration of the pancreatic architecture without any obvious untoward hepatic damages, suggesting that its use in the management of the diabetes may be valid. List of Non-standard abbreviations: D. edulis = dacryode edulis , DEnH = Dacryodes edulis n-hexane fruit extract, B.wt. = Body weight, Per os = Oral administration, NC = normal control, DC =Diabetic control, SC = Standard control, LDL-C = low density lipoprotein cholesterol, HDL-C = High density lipoprotein cholesterol, TG = Triglyceride, TC = Total cholesterol.