RAPD PCR Confirms Absence of Genetic Variation Between Insecticide Resistant Variants of the Green Peach Aphid, \u3ci\u3eMyzus Persicae\u3c/i\u3e (Homoptera: Aphididae)

Previous allozyme analysis has revealed an apparent absence of enzyme variability in the green peach aphid, Myzus persicae (Sulzer). We are interested in determining the genetic relatedness of individual M persicae clones carrying different numbers of esterase 4 (E4) gene copies conferring resistance to insecticides, in order to determine how many times and in what geographic locations resistance via gene duplication may have evolved. We have therefore extended the analysis of genetic variability in M. persicae to the DNA level using random amplification of polymorphic DNA (RAPD) with single 10 mer oligonucleotide primers. Here we report a lack of variability be- tween resistant clones in Wisconsin populations even at the DNA level Further, \u27fast\u27 E4 (FE4) variants appear to be absent from Wisconsin populations, despite FE4 variants of moderate resistance (Rl) being the most common clones in the United Kingdom. These results suggest that resistance in M. persicae may have evolved a very few times and that North American populations may differ from those in Europe by founder effects

Temperature-driven selection on metabolic traits increases the strength of an algal-grazer interaction in naturally warmed streams

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Trophic interactions are important determinants of the structure and functioning of ecosystems. As the metabolism and consumption rates of ectotherms increase sharply with temperature, there are major concerns that global warming will increase the strength of trophic interactions, destabilizing food webs, and altering ecosystem structure and function. We used geothermally warmed streams that span an 11°C temperature gradient to investigate the interplay between temperature-driven selection on traits related to metabolism and resource acquisition, and the interaction strength between the keystone gastropod grazer, Radix balthica, and a common algal resource. Populations from a warm stream (~28°C) had higher maximal metabolic rates and optimal temperatures than their counterparts from a cold stream (~17°C). We found that metabolic rates of the population originating from the warmer stream were higher across all measurement temperatures. A reciprocal transplant experiment demonstrated that the interaction strengths between the grazer and its algal resource were highest for both populations when transplanted into the warm stream. In line with the thermal dependence of respiration, interaction strengths involving grazers from the warm stream were always higher than those with grazers from the cold stream. These results imply that increases in metabolism and resource consumption mediated by the direct, thermodynamic effects of higher temperatures on physiological rates are not mitigated by metabolic compensation in the long-term, and suggest that warming will increase the strength of algal-grazer interactions with likely knock-on effects for the biodiversity and productivity of aquatic ecosystems. This article is protected by copyright. All rights reserved.Leverhulme Trust Research , Grant/AwardNumber: RP G-2013-335; ERC-StG, Grant/Award Number : ERC-StG 67727

Have Centuries of Inefficient Fishing Sustained a Wild Oyster Fishery: a Case Study

The native European flat oyster (Ostrea edulis) has declined throughout its range, due to over-exploitation, a situation mirrored in oyster stocks globally. There are three remaining oyster fisheries in England (Fal, Solent, and Thames Estuary). The Fal oyster fishery though employs traditional methods, using hand-hauled dredges from rowing punts or under sail and is home to the last commercial sailing fleet in Europe. Against a backdrop of temporary closures to protect dwindling stocks in the Solent and Thames Estuary, this study considers whether the longevity of the Fal oyster fishery is linked to the traditional methods that have been employed for centuries. Using GPS tracking in combination with on board observers, we demonstrate that dredging under sail is inefficient compared to more modern mechanically powered methods that are utilised elsewhere. A review of historical landings suggests that both overall landings and fishing effort have declined. The fishery appears to have gone through cycles of over-exploitation and one closure due to disease. However, the key to the long-term survival of the Fal oyster fishery may be linked to the traditional method of dredging. It is estimated that a switch from traditional methods to modern techniques would result in a greater than 9 fold increase in effort per season. The data presented highlight this unique fishery as a counterfactual to the increases in power seen in commercial fisheries over the last century and serve as a reference point for future studies

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

Expressed sequence tags from \u3ci\u3eDiabrotica virgifera virgifera\u3c/i\u3e midgut identify a coleopteran cadherin and a diversity of cathepsins

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect-resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine-proteases, the cathepsins

Optical Modelling and Phylogenetic Analysis Provide Clues to the Likely Function of Corneal Nipple Arrays in Butterflies and Moths.

This is the final version. Available from MDPI via the DOI in this recordThe lenses in compound eyes of butterflies and moths contain an array of nipple-shaped protuberances, or corneal nipples. Previous work has suggested that these nipples increase light transmittance and reduce the eye glare of moths that are inactive during the day. This work builds on but goes further than earlier analyses suggesting a functional role for these structures including, for the first time, an explanation of why moths are attracted to UV light. Using a phylogenetic approach and 3D optical modelling, we show empirically that these arrays have been independently lost from different groups of moths and butterflies and vary within families. We find differences in the shape of nipples between nocturnal and diurnal species, and that anti-glow reflectance levels are different at different wave-lengths, a result thereby contradicting the currently accepted theory of eye glow for predator avoidance. We find that there is reduced reflectance, and hence greater photon absorption, at UV light, which is probably a reason why moths are attracted to UV. We note that the effective refractive index at the end of the nipples is very close to the refractive index of water, allowing almost all the species with nipples to see without distortion when the eye is partially or completely wet and providing the potential to keep eyes dry. These observations provide a functional explanation for these arrays. Of special interest is the finding that their repeated and independent loss across lepidopteran phylogeny is inconsistent with the explanation that they are being lost in the 'higher', more active butterflies

Light pollution is associated with earlier tree budburst across the United Kingdom

ArticleThe ecological impact of night-time lighting is of concern because of its well-demonstrated effects on animal behaviour. However, the potential of light pollution to change plant phenology and its corresponding knock-on effects on associated herbivores are less clear. Here, we test if artificial lighting can advance the timing of budburst in trees. We took a UK-wide 13 year dataset of spatially referenced budburst data from four deciduous tree species and matched it with both satellite imagery of night-time lighting and average spring temperature. We find that budburst occurs up to 7.5 days earlier in brighter areas, with the relationship being more pronounced for later-budding species. Excluding large urban areas from the analysis showed an even more pronounced advance of budburst, confirming that the urban ‘heat-island’ effect is not the sole cause of earlier urban budburst. Similarly, the advance in budburst across all sites is too large to be explained by increases in temperature alone. This dramatic advance of budburst illustrates the need for further experimental investigation into the impact of artificial night-time lighting on plant phenology and subsequent species interactions. As light pollution is a growing global phenomenon, the findings of this study are likely to be applicable to a wide range of species interactions across the world.R.S.-Y. was supported by a GWR-ESF Studentship awarded by the University of Exeter to R.H.f.-C. The study was also founded by a BBSRC grant to R.H.f-C

A neo-W chromosome in a tropical butterfly links colour pattern, male-killing, and speciation

PublishedJournal Article© 2016, Royal Society of London. All rights reserved.Sexually antagonistic selection can drive both the evolution of sex chromosomes and speciation itself. The tropical butterfly the African Queen, Danaus chrysippus, shows two such sexually antagonistic phenotypes, the first being sex-linked colour pattern, the second, susceptibility to a male-killing, maternally inherited mollicute, Spiroplasma ixodeti, which causes approximately 100% mortality in male eggs and first instar larvae. Importantly, this mortality is not affected by the infection status of the male parent and the horizontal transmission of Spiroplasma is unknown. In East Africa, male-killing of the Queen is prevalent in a narrow hybrid zone centred on Nairobi. This hybrid zone separates otherwise allopatric subspecies with different colour patterns. Here we show that a neo-W chromosome, a fusion between the W (female) chromosome and an autosome that controls both colour pattern and malekilling, links the two phenotypes thereby driving speciation across the hybrid zone. Studies of the population genetics of the neo-W around Nairobi showthat the interaction between colour pattern and male-killer susceptibility restricts gene flow between two subspecies of D. chrysippus. Our results demonstrate how a complex interplay between sex, colour pattern, malekilling, and a neo-W chromosome, has set up a genetic ‘sink’ that keeps the two subspecies apart. The association between the neo-W and male-killing thus provides a ‘smoking gun’ for an ongoing speciation process.Matt McClements (Blink Studios Ltd) designed the figures, Bernard Rono assisted with fieldwork, and Samuel Katoi provided specimens from Watamu. Fieldwork at Silole Sanctuary (Kitengela) was sanctioned by Nani Croze, Eric Krystall, John Keen, and Mark van Rampelberg. Simon Martin scrutinized the first draft of the manuscript and made valuable suggestions for its improvement. Spiroplasma screening was carried out at icipe. D.A.S.S. thanks the Linnean Society of London and the Outreach Fund of the Royal Entomological Society of London for funding. I.J.G., D.A.S.S., W.T., and K.S. are Research Affiliates of the National Museums of Kenya

Pyrosequencing the transcriptome of the greenhouse whitefly, Trialeurodes vaporariorum reveals multiple transcripts encoding insecticide targets and detoxifying enzymes.

Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: The whitefly Trialeurodes vaporariorum is an economically important crop pest in temperate regions that has developed resistance to most classes of insecticides. However, the molecular mechanisms underlying resistance have not been characterised and, to date, progress has been hampered by a lack of nucleotide sequence data for this species. Here, we use pyrosequencing on the Roche 454-FLX platform to produce a substantial and annotated EST dataset. This 'unigene set' will form a critical reference point for quantitation of over-expressed messages via digital transcriptomics. RESULTS: Pyrosequencing produced around a million sequencing reads that assembled into 54,748 contigs, with an average length of 965 bp, representing a dramatic expansion of existing cDNA sequences available for T. vaporariorum (only 43 entries in GenBank at the time of this publication). BLAST searching of non-redundant databases returned 20,333 significant matches and those gene families potentially encoding gene products involved in insecticide resistance were manually curated and annotated. These include, enzymes potentially involved in the detoxification of xenobiotics and those encoding the targets of the major chemical classes of insecticides. A total of 57 P450s, 17 GSTs and 27 CCEs were identified along with 30 contigs encoding the target proteins of six different insecticide classes. CONCLUSION: Here, we have developed new transcriptomic resources for T. vaporariorum. These include a substantial and annotated EST dataset that will serve the community studying this important crop pest and will elucidate further the molecular mechanisms underlying insecticide resistance.CASE PhD studentship BBSRCBayer CropScienceRothamsted Researc