Biology subjects

Lawson-Handley, L.

Publications and source records attributed to Lawson-Handley, L..

3 recordsLinked to original sources

bioRxiv2020

Environmental DNA consistently outperforms established methods for detection of quagga mussels, Dreissena rostriformis bugensis in flowing water.

O_LIThe early detection of invasive non-native species (INNS) is important for informing management actions. Established monitoring methods require the collection or observation of specimens, which is unlikely at the beginning of an invasion when densities are likely to be low. Environmental DNA (eDNA) analysis is a highly promising technique for the detection of INNS - particularly during the early stages of an invasion. C_LIO_LIHere, we compared the use of traditional kick-net sampling with two eDNA approaches (targeted detection using both conventional and quantitative PCR, and passive detection via metabarcoding with conserved primers) for detection of quagga mussel, Dreissena rostriformis bugensis; a high priority INNS, along a density gradient on the River Wraysbury, UK. C_LIO_LIAll three molecular tools outperformed traditional sampling in terms of detection. Conventional PCR and qPCR both had 100% detection rate in all samples, and outperformed metabarcoding when the target species was at low densities. Additionally, quagga mussel DNA copy number (qPCR) and relative read count (metabarcoding) were significantly influenced by both mussel density and distance from source population, with distance being the most significant predictor. C_LIO_LISynthesis and application. All three molecular approaches were more sensitive than traditional kick-net sampling for the detection of the quagga mussel in flowing water, and both qPCR and metabarcoding enabled estimates of relative abundance. Targeted approaches were more sensitive than metabarcoding, but metabarcoding has the advantage of providing information on the wider community, and consequently impacts of INNS. C_LI

molecular biology↗

bioRxiv2019

Plugging the hunger gap: Organic farming supports more abundant nutritional resources for bees at critical periods

O_LIUnderstanding the decline in bee populations and their plant mutualists is of paramount concern for ecosystem health, as well as our future food security. Intensive farming practices are one of the major drivers behind such declines. Organic farming is one of the principal alternatives to conventional practices yet the evidence for its effects are mixed, with some studies showing limited benefits. C_LIO_LIWe conducted bee and floral surveys on 10 paired organic and conventional farms across Yorkshire, UK, to investigate how farming practice influenced the abundance, richness and community composition of bees and flowering plants. C_LIO_LIFirstly, we found that species richness for flowering plants and bees was similar across organic and conventional farms. Floral composition differed between organic and conventional farms with the greatest differences seen in May and June, whereas bee community composition was similar among farming practices. C_LIO_LISecondly, both bee and floral abundance were higher in organic farms. Peaks in floral abundance, and corresponding bee abundance, occurred in particular months, most notably in July, with abundance during the rest of the season being similar across both farming practices. C_LIO_LISynthesis and applications: Our results suggest that higher floral availability on organic farms corresponds with increased bee abundance. Of particular importance was the higher floral abundance during spring, in the pollinator hungry gap, where floral resources are traditionally scarce. However, conventional farms performed comparably to organic farms across the rest of the season, as well as showing similar levels of species richness, diversity and species composition for both flowering plants and bees. We suggest that targeted management on conventional farms, aimed at boosting floral abundance in the spring, when floral abundance is low, could allow conventional farms to make up the shortfall. Additionally, focusing on increasing the diversity of flowering plants, in terms of both phenology and nutritional composition, for both adult bees and their larvae, could improve bee community diversity across both farming systems. C_LI

ecology↗

bioRxiv2018

The genomic basis of colour pattern polymorphism in the harlequin ladybird

Many animal species are comprised of discrete phenotypic forms. Understanding the genetic mechanisms generating and maintaining such phenotypic variation within species is essential to comprehending morphological diversity. A common and conspicuous example of discrete phenotypic variation in natural populations of insects is the occurrence of different colour patterns, which has motivated a rich body of ecological and genetic research1-6. The occurrence of dark, i.e. melanic, forms, displaying discrete colour patterns, is found across multiple taxa, but the underlying genomic basis remains poorly characterized. In numerous ladybird species (Coccinellidae), the spatial arrangement of black and orange patches on adult elytra varies wildly within species, forming strikingly different complex colour patterns7,8. In the harlequin ladybird Harmonia axyridis, more than 200 distinct colour forms have been described, which classic genetic studies suggest result from allelic variation at a single, unknown, locus9,10. Here, we combined whole-genome sequencing, population genomics, gene expression and functional analyses, to establish that the gene pannier controls melanic pattern polymorphism in H. axyridis. We show that pannier, which encodes an evolutionary conserved transcription factor, is necessary for the formation of melanic elements on the elytra. Allelic variation in pannier leads to protein expression in distinct domains on the elytra, and thus determines the distinct colour patterns in H. axyridis. Recombination between pannier alleles may be reduced by a highly divergent sequence of ca. 170 kb in the cis-regulatory regions of pannier with a 50 kb inversion between colour forms. This likely helps maintaining the distinct alleles found in natural populations. Thus we propose that highly variable discrete colour forms can arise in natural populations through cis-regulatory allelic variation of a single gene.

evolutionary biology↗