Drones for butterfly conservation: larval habitat assessment with an unmanned aerial vehicle

Context

Evidence-based nature conservation focuses on ecological facts and the incorporation of knowledge on the ecology of species, including its entire life cycle. In butterflies, imagos and its larvae often demand specific and diverging micro-habitat structures and resources. In consequence, ecological requirements of the imaginal and pre-imaginal stage have to be taken into consideration to conduct effective conservation management.

Objective

Here we analyse ecological pre-requisites of imagos and larvae for two lycaenid butterfly species, the common blue Polyommatus icarus and the adonis blue Polyommatus bellargus. Both butterfly species occur in calcareous grasslands and mainly depend on two plant species at our study site, the horseshoe vetch Hippocrepis comosa and bird’s-foot trefoil Lotus corniculatus. These plant species serve as nectar sources and larval host plants for the two butterfly species.

Methods

First, we assessed the occurrence of imagines and larvae of the two butterfly species and recorded various micro-habitat characteristics, like the number of flower buds of the two main host plants, the surrounding vegetation height, percentage of bare soil, availability of shadow, and the distance to and geographic direction of thickets at respective sites. In a second step we took high resolution aerial pictures from our study area using an unmanned aerial vehicle (drone). Based on these aerial pictures and the information on the larvae´s habitat preference from our field observations, we trained a habitat suitability model to identify micro-habitat structures suitable for larvae of the two butterfly species.

Results

We found that abundance of imagos is positively correlated with flower bud density of the two host plants. Low vegetation height and high proportion of bare soil (but not flower bud density) positively influence egg oviposition. The calculated habitat suitability models predict the occurrence of high quality larval habitats with high prediction power (AUC = 0.72).

Conclusions

This combined data set consisting of field observations, high resolution aerial pictures taken from an unmanned aerial vehicle, and models underline that (1) species with complex life cycles may request more than one habitat niche, depending its stage of development, and (2) high resolution aerial pictures taken from drones provide valuable background data to generate habitat suitability models—even on a micro scale but covering larger parts of a landscape.

     

Membrane toxicity of antimicrobial compounds from essential oils

Natural antimicrobial compounds perform their action mainly against cell membranes. The aim of this work was to evaluate the interaction, meant as a mechanism of action, of essential oil antimicrobial compounds with the microbial cell envelope. The lipid profiles of Escherichia coli O157:H7, Staphylococcus aureus, Salmonella enterica serovar Typhimurium, Pseudomonas fluorescens, and Brochothrix thermosphacta cells treated with thymol, carvacrol, limonene, eugenol, and cinnamaldehyde have been analyzed by gas chromatography. In line with the fatty acids analysis, the treated cells were also observed by scanning electron microscopy (SEM) to evaluate structural alterations. The overall results showed a strong decrease of the unsaturated fatty acids (UFAs) for the treated cells; in particular, the C18:2trans and C18:3cis underwent a notable reduction contributing to the total UFA decreases, while the saturated fatty acid C17:0 raised the highest concentration in cinnamaldehyde-treated cells. SEM images showed that the used antimicrobial compounds quickly exerted their antimicrobial activities, determining structural alterations of the cell envelope.     

Developing nutrient profile models: a systematic approach

OBJECTIVE: Nutrient profiling can be defined as the 'the science of categorising foods according to their nutritional composition'. The purpose of the present paper is to describe a systematic and logical approach to nutrient profiling. DESIGN: A seven-stage decision-making process is proposed and, as an illustration of how the approach might operate in practice, the development of a nutrient profiling model for the purpose of highlighting breakfast cereals that are 'high in fat, sugar or salt' is described. RESULTS: The nutrient profile model developed for this paper calculates scores for foods using a simple equation. It enables breakfast cereals to be compared with each other and with other foods eaten at breakfast. CONCLUSION: Nutrient profiling is not new, but hitherto most nutrient profiling models have been developed in an unsystematic and illogical fashion. Different nutrient profiling models are needed for different purposes but a key requirement should be that they are developed using a systematic, transparent and logical process. This paper provides an example of such a process; approaches to validating nutrient profiling models are described elsewhere.     

The incidence of honey bee pests and diseases in England and Wales

The Central Science Laboratory (CSL) National Bee Unit (NBU) has been responsible for maintaining the Integrated Bee Health Programme in England and Wales since the early 1990s. The role of the Bee Health Programme is to protect the honey bee, a major pollinator of agricultural and horticultural crops and wild flora, and to provide up-to-date technical support to beekeepers. The Bee Health Programme is funded in England by the Department for Environment, Food and Rural Affairs (Defra) and in Wales by the Welsh Assembly Government (WAG). The work includes inspection of honey bee colonies, disease and pest diagnosis, development of contingency plans for emerging threats, minimising the risk of introduction of potentially serious exotic pests and diseases through importation by import risk analysis and related extension work and consultancy services to both government and industry. There is also an underpinning programme of research and development.     

Quantities of ash,Ca, and P in metacarpals,metatarsals, and tibia are better correlated with total body bone ash in growing pigs than ash,Ca, and P in other bones

The objective was to determine correlations between individual bones and total body bone ash to identify the bone that is most representative of total body bone ash in growing pigs. Twenty growing pigs were allotted to 1 of 2 diets that were formulated to contain 60% or 100% of the requirement for standardized total tract digestible (STTD) P. Both diets had an STTD Ca to STTD P ratio of 1.90:1. Growth performance and carcass weights were determined. Metacarpals, metatarsals, femur, tibia, fibula, 3rd and 4th ribs, and 10th and 11th ribs, and all other bones from the left half of the carcass were collected separately. Each bone was defatted and ashed. Pigs fed the diet containing 100% of required Ca and P had greater (P < 0.05) average daily gain, gain to feed, and ash concentration (%) in total and all individual bones except femur and fibula compared with pigs fed the diet containing 60% of required Ca and P. Calcium and P concentrations in bone ash were not affected by dietary treatments. Weights (g) of bone ash, bone Ca, and bone P were greater (P < 0.05) or tended to be greater (P < 0.10) for pigs fed the diet containing 100% of required Ca and P. Correlation coefficients between the weight of ashed metacarpals, metatarsals, and tibia and the weight of total bone ash were >0.95. In conclusion, metacarpals, metatarsals, and tibia were more representative of total body bone ash compared with other bones.     

Remnant genetic diversity detected in an ancient crop: Triticum dicoccon Schrank landraces from Asturias, Spain

Emmer wheat, Triticum dicoccon Schrank was one of the founder crops of Neolithic agriculture. Though its cultivation was largely replaced by hexaploid wheats 2000 years ago, pockets of small scale cultivation can still be found. One such area is the Asturias region of Northern Spain, where emmer wheat remains a traditional crop for high value specialist culinary uses, and farmers grow locally adapted landraces. In order to study the diversity of these landraces, we sampled emmer wheat from different regions of Asturias, and genotyped multiple plants from each village using nuclear and chloroplast microsatellites. A high level of variation was observed with markers from both genomes, including a novel chloroplast haplotype. A strong geographic structure was observed in the Asturian emmer wheats in both the chloroplast markers and the nuclear microsatellite data.