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Gradients in cuticle lightness of ectotherms have been demonstrated across latitudes and elevations. Three key hypotheses have been used to explain these macroecological patterns: the thermal melanism hypothesis (TMH), the melanism‐desiccation hypothesis (MDH) and the photo‐protection hypothesis (PPH). Yet the broad abiotic measures, such as temperature, humidity and UV‐B radiation, typically used to detect these ecogeographical patterns, are a poor indication of the microenvironment experienced by small, cursorial ectotherms like ants. We tested whether these macroecological hypotheses explaining cuticle lightness held at habitat and microclimatic level by using a vertical gradient within a tropical rainforest. We sampled 222 ant species in lowland, tropical rainforest across four vertical strata: subterranean, ground, understory and canopy. We recorded cuticle lightness, abundance and estimated body size for each species and calculated an assemblage‐weighted mean for cuticle lightness and body size for each vertical stratum. Abiotic variables (air temperature, vapour pressure deficit and UV‐B radiation) were recorded for each vertical stratum. We found that cuticle lightness of ant assemblages was vertically stratified: ant assemblages in the canopy and understory were twice as dark as assemblages in ground and subterranean strata. Cuticle lightness was not correlated with body size, and there was no support for the TMH. Rather, we attribute this cline in cuticle lightness to a combination of the MDH and the PPH. Our findings indicate that broad macroecological patterns can be detected at much smaller spatial scales and that microclimatic gradients can shape trait variation, specifically the cuticle lightness of ants. These results suggest that any changes to microclimate that occur due to land‐use change or climate warming could drive selection of ants based on cuticle colour, altering assemblage structure and potentially ecosystem functioning.

[This corrects the article DOI: 10.4103/ijdvl.IJDVL_633_18].[This corrects the article DOI: 10.4103/ijdvl.IJDVL_633_18].

The importance of colour for temperature regulation in animals remains controversial. Colour can affect an animal's temperature because all else being equal, dark surfaces absorb more solar energy than do light surfaces, and that energy is converted into heat. However, in reality, the relationship between colour and thermoregulation is complex and varied because it depends on environmental conditions and the physical properties, behaviour and physiology of the animal. Furthermore, the thermal effects of colour depend as much on absorptance of near-infrared ((NIR), 700–2500 nm) as visible (300–700 nm) wavelengths of direct sunlight; yet the NIR is very rarely considered or measured. The few available data on NIR reflectance in animals indicate that the visible reflectance is often a poor predictor of NIR reflectance. Adaptive variation in animal coloration (visible reflectance) reflects a compromise between multiple competing functions such as camouflage, signalling and thermoregulation. By contrast, adaptive variation in NIR reflectance should primarily reflect thermoregulatory requirements because animal visual systems are generally insensitive to NIR wavelengths. Here, we assess evidence and identify key research questions regarding the thermoregulatory function of animal coloration, and specifically consider evidence for adaptive variation in NIR reflectance. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.

Melasma therapy remains challenging due to limited effectiveness, side effects, and relapses. Topical tranexamic acid (TXA) is promising but requires further research to optimize its formulation. Alongside the therapeutic benefit of fractional CO2 laser (FCL) in melasma, FCL and microneedling (MN) are recognized methods for transepidermal drug delivery. Nanotechnology-based topicals can enhance drug penetration and reduce side effects. Objectives were to evaluate and compare the effectiveness of combined FCL- or MN-assisted transepidermal delivery of TXA 3% gel and FCL monotherapy versus nanotechnology-based TXA 1% microemulsion monotherapy in melasma treatment. Fifty-two melasma females were divided randomly into three groups (A, B & C) for a five-month treatment. Group A ( n  = 20), using a split-face design, received FCL on the right side (A1) and MN on the left (A2), both with TXA 3% gel applied post-session and daily. Group B ( n  = 21), also with a split-face design, received FCL with TXA 3% gel post-session only on the right side (B1), while the left side (B2) received FCL alone. Group C ( n  = 11) received TXA 1% microemulsion daily for the whole face. Evaluations included clinical, dermoscopic, and immunohistochemical SOX10 assessments, with a three-month follow-up. All groups showed a significant reduction of Hemi Melasma Area and Severity Index (Hemi-MASI), dermoscopic, and SOX10 immunoreactivity scores. Groups A1, A2, and C exhibited greater improvement compared to B1 and B2. No recurrence occurred during follow-up. Concluding that TXA 1% microemulsion is effective and safe, procedure-free monotherapy with outcomes comparable to FCL- and MN-assisted TXA 3% gel delivery for melasma.

This study aimed to evaluate the clinical efficacy of picosecond laser therapy combined with the Shumin Star in treating melasma and to explore the role of skin barrier function indicators in the assessment of this treatment process. Ninety patients with melasma were randomly divided into a study group and a control group. The study group received picosecond laser therapy combined with the Shumin Star, while the control group received only picosecond laser therapy. The clinical efficacy and adverse reactions of both groups were compared. Changes in skin barrier function before and after treatment were observed. The receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive value of skin barrier function for treatment outcomes. The clinical efficacy of the study group was significantly superior to that of the control group (95.56% versus 82.22%, P  = 0.044). After 3 months of treatment, the study group showed significant improvements of skin barrier function in TEWL, stratum corneum hydration, and sebum content, with a significantly lower MASI total score compared to the control group. During the treatment course, the incidence of adverse reactions in the study group was lower than that in the control group. Picosecond laser therapy combined with the Shumin Star is effective in treating melasma. Skin barrier function can be used to assess the clinical efficacy of this treatment, providing valuable reference values for clinical application and promotion.

Purpose This study aimed to evaluate the efficacy of amber photobiomodulation (PBM) compared to topical tranexamic acid (TXA) for the treatment of melasma. Methods In a non-inferiority randomized controlled trial, 21 women were randomized to either active PBM with placebo cream ( n  = 10) or sham PBM with 5% liposomal TXA cream ( n  = 11) for 12 weeks. A noninferiority study was chosen based on the hypothesis that PBM could offer comparable efficacy to TXA with fewer adverse effects. The primary outcome was the Melasma Area and Severity Index (MASI). Secondary outcomes included corneomelametry, Physician’s Global Assessment (PGA), quality of life measured by the MELASQoL questionnaire, and adverse events. Results No significant differences were observed in the MASI or PGA scores, within or between groups. However, the study was underpowered (51% power) due to early termination and is thus considered a pilot. A transient increase in pigmentation intensity was observed in the TXA groups at week six. Despite the lack of clinical improvement, both groups sustained improvements in quality of life. The adverse events were mild, with PBM associated with warmth and TXA with a burning sensation. The absence of MASI reduction can be attributed to the elevated environmental temperatures during the study period, consistently above historical averages. In addition, both PBM and TXA may have limited efficacy in cases of chronic or dermal melasma. Conclusion Although no significant clinical changes were detected in MASI or PGA, both treatments improved the quality of life, highlighting the importance of patient-reported outcomes. Given the small sample size and potential environmental confounders—particularly elevated temperatures during the study period—definitive conclusions about treatment efficacy cannot be drawn. Future studies should consider optimized protocols and/or combination therapies. Trial Registration: Clinical Trials No. NCT05326997, April 14th 2022.

The mutation responsible for the black carbonaria morph of the peppered moth is identified as a transposable element within the cortex gene. The look of Lepidoptera driven by cortex The darkening of the peppered moth Biston betularia , the phenomenon known as industrial melanism, is a textbook example of evolutionary biology in action. However, the genetic background of the black or c arbonaria variants has remained unclear. Building on their earlier work that isolated the gene responsible to within a roughly 400-kilobase region containing 13 genes, Ilik Saccheri and colleagues have identified the melanism-causing event as the insertion of a class II transposable element into the first intron of a gene called cortex . Statistical inference indicates that the polymorphism occurred around 1819, when the Industrial Revolution was well under way. In a separate study, Nicola Nadeau et al . report that colour patterning in butterflies of the genus Heliconius is also mediated by expression of the cortex gene, apparently co-opted to control the rate of scale cell development, on which colour depends. Taken together, these two papers suggest that cortex , conserved widely within Lepidoptera, is a major target for natural selection acting on colour and pattern variation. Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth ( Biston betularia ): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black ( carbonaria ) form, driven by the interaction between bird predation and coal pollution 1 . The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria – typica polymorphism, and the gene it influences, are unknown 2 . Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex . Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of ‘jumping genes’ as a source of major phenotypic novelty 3 .

This study aimed to evaluate the effectiveness of isolated treatment with retinoic acid and its combination with the microneedling technique in facial melasma, seeking to associate these results with possible oxidative damage. This is a blinded randomized clinical trial with 42 women with facial melasma (skin phototype I–IV), randomized into Group A (microneedling and 5% retinoic acid) or Group B (5% retinoic acid alone). Four procedures were applied with 15 days intervals (4 blood collections). Clinical improvement was assessed using the Melasma Area Severity Index (MASI). Serum oxidative stress levels were evaluated by protein oxidation (carbonyl), lipid peroxidation (TBARS) and sulfhydryl groups, as well as enzyme activities of superoxide dismutase (SOD) and catalase (CAT). The statistical analyzes were performed by generalized estimation equation (GEE). There was a reduction in MASI scale and TBARS levels in both groups over time ( p  < 0.05), with no difference between groups ( p  = 0.416). There was also a substantial increase in the carbonyl levels at 30 days ( p  = 0.002). The SOD activity decreased after 30 days, regardless of group ( p  < 0.001), which was maintained after 60 days. In Group A, there was a reduction in sulfhydryl levels at 60 days ( p  < 0.001). It is important to highlight that both groups demonstrated efficacy in the clinical improvement of melasma within at least 60 days, reducing the MASI score by almost 50%. However, microneedling with retinoic acid seems to be the worst treatment because there is a reduction in the non-enzymatic antioxidant defense, which is important to protect against oxidative stress.

Background Melanism in wild felids represents an intriguing evolutionary trait, potentially advantageous under specific ecological conditions, but the genetic basis of this phenotype remains unclear in many populations. Here, we explored melanism in the Indian leopard ( Panthera pardus fusca ) by integrating whole-genome sequencing with evolutionary and structural analyses. Results We identified a single-point mutation (p.C117F) in the agouti signalling protein (ASIP) gene. Evolutionary analyses indicated signs of positive selection acting on the ASIP locus, while codon usage patterns revealed no impairment in translational efficiency. Computational predictions (SIFT, PROVEAN) classified the mutation as functionally damaging. Structural modelling combined with molecular dynamics simulations revealed significant disruptions in the stability, helical content, and receptor-binding affinity of the mutated ASIP protein compared to the wild type. The mutation notably diminished ASIP’s inhibitory interaction with melanocortin-1 receptor (MC1R), which is crucial for melanogenesis regulation. Machine-learning models differentiated between mutant and wild-type protein structures by analysing molecular features. Conclusions Our results support the conclusion that the p.C117F mutation significantly contributes to melanism in Indian leopards, shedding new light on this trait’s molecular underpinnings and evolutionary history. This study identifies the p.C117F mutation as a key driver of melanism in leopards of the Indian subcontinent, providing mechanistic insight into the evolution of complex phenotypes in non-model species.

The two-spot ladybird, Adalia bipunctata, is polymorphic for elytral colour pattern. Whilst colour pattern polymorphism is complex, there are two predominant morphs: melanic and typical, which vary spatially in frequency. In the UK the melanic form has historically been most common in the industrialized North West of England. Evidence from industrial midland populations showed a decline in melanic frequency between 1960 and 1986 concordant with de-industrialization. We resampled the population of Merseyside in the North West of England, where the highest frequencies of melanic forms were historically observed, and compared our samples to data previously collected in 1962-1963. Data was consistent with a decline in frequency of melanics in the 60 year interval, but the melanic form was nevertheless still observed at around 30% frequency. We estimate the melanic allele has declined from 60-67% frequency to 13-18% frequency over the last 60 years, and that selection favouring the typical form has been of the order of 5-7% per generation. We note that selection against melanics in Wirral/Merseyside has been less strong than that observed in other Northern populations. We conclude that the decline in the melanic form is consistent with industrial thermal melanism as a primary factor driving melanism, but de-industrialization has not been sufficient to cause complete loss of the melanic allele in this location.