Insects in biodiversity conservation: some perspectives and directives

The Insecta is the most speciose class in the Animal Kingdom. The insect-plant relationship is the dominant biotic interaction, yet plants have many times the biomass of all animals together. The functional significance of insects is enormous, owing to the large numbers of individuals and great intra-and interspecific variety. Lack of human appreciation of importance, coupled with the general disregard and dislike of insects, is an enormous perception impediment to their conservation. This impediment coupled with the taxonomic impediment (at most only about 7–10% of insects are scientifically described) must be overcome for realistic biodiversity conservation. As it is not possible to know all the species relative to the rate at which they are becoming extinet, it is essential to conserve as many biotopes and landscapes as possible. These would be for typical species and communities, as well as for endemic sinks. It is also essential to preserve speciesdynamo areas as an insurance for future biodiversity. Preserved areas must also be linked by movement and gene-flow corridors as much as possible. Recognition, functional importance, taxic uniqueness, typicalness, genetic variation and important behavioural traits place much more emphasis on qualitative biodiversity conservation than on quantitative approaches. Ecological entomologists play a significant double role, suppressing noxious populations on crops, livestock and other products, while at the same time identifying and using beneficial species. There are well-known inherent and environmental risks with many traditional control methods and high risks with the use of genetically engineered biopesticide baculoviruses. Preservation technologies, where individuals are held in suspended animation, must be developed soon. However, such technologies, as with restoration activities such as site restoration, captive breeding, reintroductions and translocations, all require considerable knowledge and economic iput to be predictably successful. Ecological restoration involves so many biotic and abiotic interactions in even the simplest of communities, that predictiveness under all potential conditions is virtually unattainable. Instead, there should be strong focus on the preservation and conservation of as many, and as large as possible, pristine and near-pristine unique and typical landscapes as soon as possible.     

Assessing durum wheat ear and leaf metabolomes in the field through hyperspectral data

Hyperspectral techniques are currently used to retrieve information concerning plant biophysical traits, predominantly targeting pigments, water, and nitrogen‐protein contents, structural elements, and the leaf area index. Even so, hyperspectral data could be more extensively exploited to overcome the breeding challenges being faced under global climate change by advancing high‐throughput field phenotyping. In this study, we explore the potential of field spectroscopy to predict the metabolite profiles in flag leaves and ear bracts in durum wheat. The full‐range reflectance spectra (visible (VIS)‐near‐infrared (NIR)‐short wave infrared (SWIR)) of flag leaves, ears and canopies were recorded in a collection of contrasting genotypes grown in four environments under different water regimes. GC‐MS metabolite profiles were analyzed in the flag leaves, ear bracts, glumes, and lemmas. The results from regression models exceeded 50% of the explained variation (adj‐R² in the validation sets) for at least 15 metabolites in each plant organ, whereas their errors were considerably low. The best regressions were obtained for malate (82%), glycerate and serine (63%) in leaves; myo‐inositol (81%) in lemmas; glycolate (80%) in glumes; sucrose in leaves and glumes (68%); γ‐aminobutyric acid (GABA) in leaves and glumes (61% and 71%, respectively); proline and glucose in lemmas (74% and 71%, respectively) and glumes (72% and 69%, respectively). The selection of wavebands in the models and the performance of the models based on canopy and VIS organ spectra and yield prediction are discussed. We feel that this technique will likely to be of interest due to its broad applicability in ecophysiology research, plant breeding programmes, and the agri‐food industry.     

The diffusion model for migration and selection in a plant population

 The diffusion approximation is derived for migration and selection at a multiallelic locus in a partially selfing plant population subdivided into a lattice of colonies. Generations are discrete and nonoverlapping; both pollen and seeds disperse. In the diffusion limit, the genotypic frequencies at each point are those determined at equilibrium by the local rate of selfing and allelic frequencies. If the drift and diffusion coefficients are taken as the appropriate linear combination of the corresponding coefficients for pollen and seeds, then the migration terms in the partial differential equation for the allelic frequencies have the standard form for a monoecious animal population. The selection term describes selection on the local genotypic frequencies. The boundary conditions and the unidimensional transition conditions for a geographical barrier and for coincident discontinuities in the carrying capacity and migration rate have the standard form. In the diallelic case, reparametrization renders the entire theory of clines and of the wave of advance of favorable alleles directly applicable to plant populations. Received 30 August 1995; received in revised form 23 February 1996