Despite compelling evidence for substantial individual differences in cognitive performance, it is unclear whether cognitive ability influences fitness of wild animals. In many animals, environmental stressors experienced in utero can produce substantial variation in the cognitive abilities of offspring. In reptiles, incubation temperatures experienced by embryos can influence hatchling brain function and learning ability. Under climate warming, the eggs of some lizard species may experience higher temperatures, which could affect the cognitive abilities of hatchlings. Whether such changes in cognitive abilities influence the survival of hatchlings is unknown. To determine whether incubation-induced changes in spatial learning ability affect hatchling survival, we incubated velvet gecko, Amalosia lesueurii, eggs using two fluctuating temperature regimes to mimic current (cold) versus future (hot) nest temperatures. We measured the spatial learning ability of hatchlings from each treatment, and released individually marked animals at two field sites in southeastern Australia. Hatchlings from hot-incubated eggs were slower learners than hatchlings from cold-incubated eggs. Survival analyses revealed that hatchlings with higher learning scores had higher survival than hatchlings with poor learning scores. Our results show that incubation temperature affects spatial learning ability in hatchling lizards, and that such changes can influence the survival of hatchlings in the wild.
13 April 2023 in Critical Reviews in Analytical Chemistry
The field of analytical chemistry has been significantly advanced by the availability of state-of-the-art instrumentation, allowing for the development of novel applications in this field. However, in many cases, the direct interpretation of the recorded data is often not straightforward, hence some level of pre-processing is required (e.g., baseline correction, derivatives, normalization, smoothing). These techniques have become a critical first step for the successful analysis of the data recorded, and it is recommended to use them before the application of chemometrics (e.g., classification, calibration development). The aim of this paper is to provide with an overview of the most used pre-processing methods applied to instrumental analytical methods (e.g., spectroscopy, chromatography). Examples of their application in near infrared and UV-VIS spectroscopy as well as in gas chromatography will be also discussed. Overall, this paper provides with a comprehensive understanding of pre-processing techniques in analytical chemistry, highlighting their importance during the analysis and interpretation of data, as well as during the development of accurate and reliable chemometric models.
The tropical island nation of Sri Lanka has a rich terrestrial and aquatic reptilian fauna. However, like most other tropical countries, the threat of climate change to its reptile diversity has not been adequately addressed, in order to manage and mitigate the extinction threats that climate change poses. To address this shortfall, a review of the international literature regarding climate change impacts on reptiles was undertaken with specific reference to national requirements, focusing on predicted changes in air temperature, rainfall, water temperature, and sea level. This global information base was then used to specify a national program of research and environmental management for tropical countries, which is urgently needed to address the shortcomings in policy-relevant data, its availability and access so that the risks of extinction to reptiles can be clarified and mitigated. Specifically, after highlighting how climate change affects the various eco-physiological features of reptiles, we propose research gaps and various recommendations to address them. It is envisaged that these assessments will also be relevant to the conservation of reptilian biodiversity in other countries with tropical and subtropical climatic regimes
In many regions, the frequency and duration of summer heatwaves is predicted to increase in future. Hotter summers could result in higher temperatures inside lizard nests, potentially exposing embryos to thermally stressful conditions during development. Potentially, developmentally plastic shifts in thermal tolerance could allow lizards to adapt to climate warming. To determine how higher nest temperatures affect the thermal tolerance of hatchling geckos, we incubated eggs of the rock-dwelling velvet gecko, Amalosia lesueurii, at two fluctuating temperature regimes to mimic current nest temperatures (mean 23.2°C, range 10–33°C, ‘cold’) and future nest temperatures (mean 27.0°C, range 14–37°C, ‘hot’). Hatchlings from the hot incubation group hatched 27 days earlier and had a lower critical thermal maximum (CTmax 38.7°C) and a higher critical thermal minimum (CTmin 6.2°C) than hatchlings from cold incubation group (40.2 and 5.7°C, respectively). In the field, hatchlings typically settle under rocks near communal nests. During the hatching period, rock temperatures ranged from 13 to 59°C, and regularly exceeded the CTmax of both hot- and cold-incubated hatchlings. Because rock temperatures were so high, the heat tolerance of lizards had little effect on their ability to exploit rocks as retreat sites. Instead, the timing of hatching dictated whether lizards could exploit rocks as retreat sites; that is, cold-incubated lizards that hatched later encountered less thermally stressful environments than earlier hatching hot-incubated lizards. In conclusion, we found no evidence that CTmax can shift upwards in response to higher incubation temperatures, suggesting that hotter summers may increase the vulnerability of lizards to climate warming.