Open Access

Coat color and pattern are a distinguished feature in mammalian carnivores, shaped by climatic cycles and habitat type. It can be expressed in various ways, such as gradients, polymorphisms, and rare color variants. Although natural selection explains much of the phenotypic variation found in the wild, genetic drift and heterozygote deficiency, as prominent in small and fragmented populations, may also affect phenotypic variability through the fixation of recessive alleles. The aim of this study was to test whether rare color variants in the wild could relate to a deficiency of heterozygotes, resulting from habitat fragmentation and small population size. We present an overview of all rare color variants in the order Carnivora, and compiled demographic and genetic data of the populations where they did and did not occur, to test for significant correlations. We also tested how phylogeny and body weight influenced the presence of color variants with phylogenetic generalized linear mixed models (PGLMMs). We found 40 color-variable species and 59 rare color variants. In 17 variable phenotypic populations for which genetic diversity was available, the average AR was 4.18, HO = 0.59, and HE= 0.66, and FIS= 0.086. We found that variable populations displayed a significant reduction in heterozygosity and allelic richness compared to non-variable populations across species. We also found a significant negative correlation between population size and inbreeding coefficients. Therefore, it is possible that small effective size had phenotypic consequences on the extant populations. The high frequency of the rare color variants (averaging 20%) also implies that genetic drift is locally overruling natural selection in small effective populations. As such, rare color variants could be added to the list of phenotypic consequences of inbreeding in the wild.

Agricultural intensification, driven by increasing food demand, is one of the main drivers of global biodiversity loss. Pesticides, including fungicides, may increase crop yield but pose substantial threats to the environment. However, our current knowledge on the effects of fungicides on biodiversity suffers from less research interest compared to other pesticides and a neglect of insect herbivores. We here investigate the effects of a commercially available, ready-to-use difenoconazole fungicide on a non-target insect, the butterfly Pieris napi , under controlled laboratory conditions. When being fed with fungicide-treated host plants, butterfly larvae showed a strongly reduced survival (15%) compared to controls (60%). Survival in larvae treated with the fungicide plus an insecticide was only 1%. Sublethal effects of the fungicide included prolonged development and reduced adult size. Our results indicate a surprisingly high toxicity of the tested fungicide formulation on P. napi . Based on the available literature, we speculate that triazole fungicides may be in general toxic to Lepidoptera and potentially other herbivorous insects. This study contributes to the growing evidence that fungicides may well be involved in the loss of insect biodiversity in agricultural landscapes at the global scale.

In recent decades, severe declines in biodiversity have been observed globally, with agricultural intensification being one of the key drivers. However, the abandonment of traditional land-use practices may also negatively affect diversity. Setting aside steep-slope vineyards, driven by heavy workloads and diminishing profitability, may pose a major challenge to biodiversity conservation and related ecosystem services in Germany. Here, we compare ground-dwelling beetle taxonomic and functional diversity across four management categories: (1) conventionally managed vineyards, (2) set-aside vineyards that are now managed as grazed grasslands, (3) set-aside vineyards that are now managed as mown grasslands, and (4) vineyard fallows. Using pitfall traps, we examined 10 sites per management category along the Upper Middle Rhine Valley in southwestern Germany. We show that conventionally managed vineyards and grazed grasslands exhibited the highest species richness, taxonomic and functional diversity, while fallows showed strongly reduced values. The same applies to the ‘conservation value’ of beetle assemblages, being highest on conventionally managed vineyards and grazed grasslands but lowest on fallows. Especially open landscape and xerothermic beetle species were negatively affected by abandonment. Beetle diversity was additionally affected by landscape composition, with (semi)-natural habitats having positive effects. Thus, our findings suggest that conventionally managed vineyards can provide valuable habitats for taxonomically and functionally diverse ground beetle communities, and that grazing represents an appropriate alternative for set-aside sites. Implications for insect conservation Our results show that some sort of management is important to halt secondary succession in xerothermic landscapes to preserve landscape heterogeneity and promote ground-dwelling beetle diversity. To this end, grazing seems to be especially suitable.

The adaptive value of intraspecific phenotypic variability, as well as the extent to which this is balanced by selection and genetic drift, is still relatively poorly explored. An intriguing population of leopard ( Panthera pardus ) occurs in the Cape Floristic Region, South Africa, where body mass is almost half that of leopards occurring in the savanna biome. In this study, we used whole-genome resequencing data of 43 leopards, including 10 from the Western Cape province (WCP). We explored spatial population structure and measured genome-wide diversity, including runs of homozygosity and genetic load. We compared their population demographic history to ‘savanna leopards’ in northern South Africa, and tested for signatures of selection that drive genomic and phenotypic differences. We found that WCP is distinct from other leopards in Africa, and that it diverged 20-24 thousand years ago from northern South Africa, which is in contrast to a lack of genome-wide differentiation found in previous studies. Because we found no obvious signs of genetic drift in WCP, the divergence is likely to have been caused by their population demographic history. We also found enriched genes that may relate to the local phenotype, possibly as an evolutionary response to food-scarce conditions. Leopards in the Cape Floristic Region utilize a unique landscape, which varies biologically in prey availability and vegetation structure, and anthropogenically with the province’s rapidly growing human population. Considering the local adaptation and divergence found in both mitochondrial and nuclear genomes, leopards in the Cape can be considered an evolutionary significant unit (ESU).