Historical changes in the phenology of British Odonata are related to climate

Responses of biota to climate change take a number of forms including distributional shifts, behavioural changes and life history changes. This study examined an extensive set of biological records to investigate changes in the timing of life history transitions (specifically emergence) in British Odonata between 1960 and 2004. The results show that there has been a significant, consistent advance in phenology in the taxon as a whole over the period of warming that is mediated by life history traits. British odonates significantly advanced the leading edge (first quartile date) of the flight period by a mean of 1.51 ±0.060 (SEM, n=17) days per decade or 3.08±1.16 (SEM, n=17) days per degree rise in temperature when phylogeny is controlled for. This study represents the first review of changes in odonate phenology in relation to climate change. The results suggest that the damped temperature oscillations experienced by aquatic organisms compared with terrestrial organisms are sufficient to evoke phenological responses similar to those of purely terrestrial taxa

Comparison of Similarity Coefficients used for Cluster Analysis with Amplified Fragment Length Polymorphism Markers in the Silkworm, Bombyx mori

Establishing accurate genetic similarity and dissimilarity between individuals is an essential and decisive point for clustering and analyzing inter and intra population diversity because different similarity and dissimilarity indices may yield contradictory outcomes. We assessed the variations caused by three commonly used similarity coefficients including Jaccard, Sorensen-Dice and Simple matching in the clustering and ordination of seven Iranian native silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), strains analyzed by amplified fragment length polymorphism markers. Comparisons among the similarity coefficients were made using the Spearman correlation analysis, dendrogram evaluation (visual inspection and consensus fork index - CIC), projection efficiency in a two-dimensional space, and groups formed by the Tocher optimization procedure. The results demonstrated that for almost all methodologies, the Jaccard and Sorensen-Dice coefficients revealed extremely close results, because both of them exclude negative co-occurrences. Due to the fact that there is no guarantee that the DNA regions with negative cooccurrences between two strains are indeed identical, the use of coefficients such as Jaccard and Sorensen-Dice that do not include negative co-occurrences was imperative for closely related organisms

Effect of Biodiversity Changes in Disease Risk: Exploring Disease Emergence in a Plant-Virus System

The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species

Effectiveness of vasectomy using cautery

BACKGROUND: Little evidence supports the use of any one vas occlusion method. Data from a number of studies now suggest that there are differences in effectiveness among different occlusion methods. The main objectives of this study were to estimate the effectiveness of vasectomy by cautery and to describe the trends in sperm counts after cautery vasectomy. Other objectives were to estimate time and number of ejaculations to success and to determine the predictive value of success at 12 weeks for final status at 24 weeks. METHODS: A prospective, non-comparative observational study was conducted between November 2001 and June 2002 at 4 centers in Brazil, Canada, the UK, and the US. Four hundred men who chose vasectomy were enrolled and followed for 6 months. Sites used their usual cautery vasectomy technique. Earlier and more frequent than normal semen analyses (2, 5, 8, 12, 16, 20, and 24 weeks after vasectomy) were performed. Planned outcomes included effectiveness (early failure based on semen analysis), trends in sperm counts, time and number of ejaculations to success, predictive value of success at 12 weeks for the outcome at 24 weeks, and safety evaluation. RESULTS: A total of 364 (91%) participants completed follow-up. The overall failure rate based on semen analysis was 0.8% (95% confidence interval 0.2, 2.3). By 12 weeks 96.4% of participants showed azoospermia or severe oligozoospermia (< 100,000 sperm/mL). The predictive value of a single severely oligozoospermia sample at 12 weeks for vasectomy success at the end of the study was 99.7%. One serious unrelated adverse event and no pregnancies were reported. CONCLUSION: Cautery is a very effective method for occluding the vas. Failure based on semen analysis is rare. In settings where semen analysis is not practical, using 12 weeks as a guideline for when men can rely on their vasectomy should lessen the risk of failure compared to using a guideline of 20 ejaculations after vasectomy

Statistical validation of megavariate effects in ASCA

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

The Old Ladies of the Seed Harvester ant Pogonomyrmex Rugosus: Foraging Performed by Two Groups of Workers

We examined temporal polyethism in Pogonomyrmex rugosus, predicting a pattern of decreasing age from foragers to nest maintenance workers to individuals that were recruited to harvest a temporary food source. Nest maintenance workers were younger than foragers, as indicated by their heavier mass and lower mandibular wear. In contrast, recruited foragers were similar in mass to foragers but they displayed higher mandibular wear, suggesting that they were at least as old as foragers. Longevity estimates for marked individuals of these two latter task groups showed mixed results. Higher mandibular wear of recruited foragers suggests that they did not follow the normal sequence for temporal polyethism, but rather that they functioned as seed-millers, which should more quickly abrade their dentition. This would be the first demonstration of specialist milling individuals in a monomorphic seed-harvester ant

Osvaldo and Isis retrotransposons as markers of the Drosophila buzzatii colonization in Australia

Background: Transposable elements (TEs) constitute an important source of genetic variability owing to their jumping and regulatory properties, and are considered to drive species evolution. Several factors that are able to induce TE transposition in genomes have been documented (for example environmental stress and inter- and intra-specific crosses) but in many instances the reasons for TE mobilisation have yet to be elucidated. Colonising populations constitute an ideal model for studying TE behaviour and distribution as they are exposed to different environmental and new demographic conditions. In this study, the distribution of two TEs, Osvaldo and Isis, was examined in two colonising populations of D. buzzatii from Australia. Comparing Osvaldo copy numbers between Australian and Old World (reported in previous studies) colonisations provides a valuable tool for elucidating the colonisation process and the effect of new conditions encountered by colonisers on TEs. Results: The chromosomal distributions of Osvaldo and Isis retrotransposons in two colonising populations of D. buzzatii from Australia revealed sites of high insertion frequency (>10%) and low frequency sites. Comparisons between Osvaldo insertion profiles in colonising populations from the Old World and Australia demonstrate a tendency towards a higher number of highly occupied sites with higher insertion frequency in the Old World than in Australian populations. Tests concerning selection against deleterious TE insertions indicate that Isis is more controlled by purifying selection than Osvaldo. The distribution of both elements on chromosomal arms follows a Poisson distribution and there are non-significant positive correlations between highly occupied sites and chromosomal inversions. Conclusions: The occupancy profile of Osvaldo and Isis retrotransposons is characterised by the existence of high and low insertion frequency sites in the populations. These results demonstrate that Australian D. buzzatii populations were subjected to a founder effect during the colonisation process. Moreover, there are more sites with high insertion frequency in the Old World colonisation than in the Australian colonisation, indicating a probable stronger bottleneck effect in Australia. The results suggest that selection does not seem to play a major role, compared to demography, in the distribution of transposable elements in the Australian populations

Assessment of Attractiveness of Plants as Roosting Sites for the Melon Fly, Bactrocera cucurbitae, and Oriental Fruit Fly, Bactrocera dorsalis

The use of toxic protein bait sprays to suppress melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), populations typically involves application to vegetation bordering agricultural host areas where the adults seek shelter (“roost”). Although bait spray applications for suppression of oriental fruit fly, Bactrocera dorsalis (Hendel), populations have traditionally been applied to the host crop, rather than to crop borders, roosting by oriental fruit flies in borders of some crop species, such as papaya, Carica papaya L. (Brassicales: Caricaceae), suggests that bait spray applications to crop borders could also help in suppression of B. dorsalis populations. In order to develop improved recommendations for application of bait sprays to border plants for suppression of melon fly and oriental fruit fly populations, the relative attractiveness of a range of plant species, in a vegetative (non-flowering) stage, was tested to wild melon fly and oriental fruit fly populations established in a papaya orchard in Hawaii. A total of 20 plant species were evaluated, divided into four categories: 1) border plants, including corn, Zea mays L. (Poales: Poaceae), windbreaks and broad-leaved ornamentals, 7 species; 2) weed plants commonly found in agricultural fields in Hawaii, 6 species; 3) host crop plants, 1 species- zucchini, Cucurbita pepo L. (Violales: Curcurbitaceae), and 4) locally grown fruit trees, 6 species. Plants were established in pots and placed in an open field, in clusters encircling protein bait traps, 20 m away from the papaya orchard. Castor bean, Ricinus communis L. (Euphorbiales: Euphorbiaceae), panax, Polyscias guilfoylei (Bull) Bailey (Apiales: Araliaceae), tiger's claw, Erythnna variegata L. (Fabales: Fabaceae), and guava, Psidium guajava L. (Myrtales: Myrtaceae) were identified as preferred roosting hosts for the melon fly, and tiger's claw, panax, castor bean, Canada cocklebur, Xanthium strumarium L. (Asterales: Asteraceae), Brazilian pepper tree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), ti plant, Cordyline terminate (L.) Chev.(Liliales: Liliaceae), guava and several Citrus spp. were identified as preferred roosting hosts for oriental fruit fly. Guava had not previously been identified as a preferred roosting host for melon fly. Other than for the use of panax as a roosting host, there has previously been little attention to roosting hosts for oriental fruit fly. Establishment of preferred roosting hosts as crop borders may help to improve suppression of both fruit fly species by providing sites for bait spray applications. Further research is needed to assess the use of vegetation bordering other host crops as roosting hosts, especially for oriental fruit fly