Application of the Danish pesticide load indicator to arable agriculture in the United Kingdom.

Pesticides are an important component of worldwide agriculture systems and have contributed to significant increases in crop quality and yields and therefore to food security. However, despite their societal benefits, pesticides can be hazardous to humans and the environment. Therefore, effective pesticide polices are needed that balance the societal and economic benefits with the unintentional and undesirable environmental and health impacts. As a result, there has been consistent policy interest in pragmatic and practical techniques that are suitable for assessing the environmental and human health implications of agricultural pesticide use from a national perspective for assisting in the development of policy initiatives and for communicating policy outcomes to the public. The work described herein explored the appropriateness of the Danish Pesticide Load Indictor for assessing agricultural pesticides applied in the United Kingdom from 2016 and 2018. The findings for the two datasets appear broadly comparable, suggesting that the overall environmental load from pesticides on the U.K. environment remained relatively constant during this period. Regional differences in environmental load and the major contributing substances were identified. Where large differences between the two years were seen, regulatory interventions appear to have been the cause. Overall, the indicator behaves as expected and appears to be sufficiently responsive to changes in pesticide use. However, various concerns were identified that may lead to modifications in how the indicator is calculated and what parameters are included to make it better able to deliver U.K. policy objectives.

Early warning systems in biosecurity; translating risk into action in predictive systems for invasive alien species.

Invasive alien species (IAS) are one of the most severe threats to biodiversity and are the subject of varying degrees of surveillance activity. Predictive early warning systems (EWS), incorporating automated surveillance of relevant dataflows, warning generation and dissemination to decision makers are a key target for developing effective management around IAS, alongside more conventional early detection and horizon scanning technologies. Sophisticated modelling frameworks including the definition of the 'risky' species pool, and pathway analysis at the macro and micro-scale are increasingly available to support decision making and to help prioritise risks from different regions and/or taxa. The main challenges in constructing such frameworks, to be applied to border inspections, are (i) the lack of standardisation and integration of the associated complex digital data environments and (ii) effective integration into the decision making process, ensuring that risk information is disseminated in an actionable way to frontline surveillance staff and other decision makers. To truly achieve early warning in biosecurity requires close collaboration between developers and end-users to ensure that generated warnings are duly considered by decision makers, reflect best practice, scientific understanding and the working environment facing frontline actors. Progress towards this goal will rely on openness and mutual understanding of the role of EWS in IAS risk management, as much as on developments in the underlying technologies for surveillance and modelling procedures.

Phylogenetic analyses suggest that diversification and body size evolution are independent in insects.

BACKGROUND: Skewed body size distributions and the high relative richness of small-bodied taxa are a fundamental property of a wide range of animal clades. The evolutionary processes responsible for generating these distributions are well described in vertebrate model systems but have yet to be explored in detail for other major terrestrial clades. In this study, we explore the macro-evolutionary patterns of body size variation across families of Hexapoda (insects and their close relatives), using recent advances in phylogenetic understanding, with an aim to investigate the link between size and diversity within this ancient and highly diverse lineage. RESULTS: The maximum, minimum and mean-log body lengths of hexapod families are all approximately log-normally distributed, consistent with previous studies at lower taxonomic levels, and contrasting with skewed distributions typical of vertebrate groups. After taking phylogeny and within-tip variation into account, we find no evidence for a negative relationship between diversification rate and body size, suggesting decoupling of the forces controlling these two traits. Likelihood-based modeling of the log-mean body size identifies distinct processes operating within Holometabola and Diptera compared with other hexapod groups, consistent with accelerating rates of size evolution within these clades, while as a whole, hexapod body size evolution is found to be dominated by neutral processes including significant phylogenetic conservatism. CONCLUSIONS: Based on our findings we suggest that the use of models derived from well-studied but atypical clades, such as vertebrates may lead to misleading conclusions when applied to other major terrestrial lineages. Our results indicate that within hexapods, and within the limits of current systematic and phylogenetic knowledge, insect diversification is generally unfettered by size-biased macro-evolutionary processes, and that these processes over large timescales tend to converge on apparently neutral evolutionary processes. We also identify limitations on available data within the clade and modeling approaches for the resolution of trees of higher taxa, the resolution of which may collectively enhance our understanding of this key component of terrestrial ecosystems.

Diet Evolution and Clade Richness in Hexapoda: A Phylogenetic Study of Higher Taxa.

Hexapoda, the insects and their relatives, includes over half of all described species. Because large proportions of this diversity cluster within a small set of phytophagous groups, dietary substrates have been proposed to shape patterns of richness within the clade through antagonistic coevolution and zones of ecological opportunity. Here we explore these processes in the context of a recent dated phylogeny of Hexapod families. Our results indicate phylogenetic clustering of specialized ecologies, such as phytophagy and parasitism, but reveal no consistent associations between the use of particular dietary substrates and clade richness. We also find no evidence that diets expected to promote antagonistic coevolution are consistently associated with elevated species richness or that sister clades differing in dietary state are associated with greater-than-expected differences in richness. We do, however, identify variation in the age of, and transition rates among, dietary states that are likely to play a role in the observed heterogeneity in richness among dietary classes. Based on these findings, we suggest remaining circumspect about the generality of adaptive zones based on broad dietary groupings as an explanation for hexapod richness and suggest that richness heterogeneity may be better explained by origination and transition rates as well as variation within dietary categories.

Phylogenetic distribution of extant richness suggests metamorphosis is a key innovation driving diversification in insects.

Insects and their six-legged relatives (Hexapoda) comprise more than half of all described species and dominate terrestrial and freshwater ecosystems. Understanding the macroevolutionary processes generating this richness requires a historical perspective, but the fossil record of hexapods is patchy and incomplete. Dated molecular phylogenies provide an alternative perspective on divergence times and have been combined with birth-death models to infer patterns of diversification across a range of taxonomic groups. Here we generate a dated phylogeny of hexapod families, based on previously published sequence data and literature derived constraints, in order to identify the broad pattern of macroevolutionary changes responsible for the composition of the extant hexapod fauna. The most prominent increase in diversification identified is associated with the origin of complete metamorphosis, confirming this as a key innovation in promoting insect diversity. Subsequent reductions are recovered for several groups previously identified as having a higher fossil diversity during the Mesozoic. In addition, a number of recently derived taxa are found to have radiated following the development of flowering plant (angiosperm) floras during the mid-Cretaceous. These results reveal that the composition of the modern hexapod fauna is a product of a key developmental innovation, combined with multiple and varied evolutionary responses to environmental changes from the mid Cretaceous floral transition onward.