International plant virus epidemiology workshop : resistance to viruses and vectors, temperate and tropical plants

The whitefly #Bemisia tabaci is a well known vector of African Cassava Mosaic in tropical countries. By using isozyme electrophoresis (esterase patterns) and host-range studies, tow types of #B. tabaci were characterised : one breeding mainly on cassava, the other breeding on all plants other than cassava. Each types shows a different esterase pattern. (Résumé d'auteur

International plant virus epidemiology workshop : resistance to viruses and vectors, temperate and tropical plants

La mouche blanche #Bemisia tabaci (#Homoptera : #Aleyrodidae$) est le seul insecte connu vecteur de la mosaïque africaine du manioc. Des essais aux champs sont en cours en basse Côte d'Ivoire pour étudier l'écologie des populations aux stades immatures sur le manioc. Des données préliminaires sur la vitesse de développement et le taux de mortalité de chaque stade, la distribution à l'intérieur de la plante et l'évolution des populations dans le temps, sont présentées ici. Les mensurations morphomètriques ont révélé qu'on peut distinguer entre les sexes au dernier stade larvaire. (Résumé d'auteur

Benign breast disease and subsequent breast cancer: English record linkage studies

BACKGROUND: Benign breast disease (BBD) increases the risk of breast cancer, but details of the relationship would benefit from further study in the UK. METHODS: Analysis of linked statistical abstracts of hospital data, including a cohort of 20 976 women with BBD in an Oxford data set and 89 268 such women in an English national data set. RESULTS: Rate ratios (RRs) for breast cancer, comparing BBD and comparison cohorts in these two data sets, were 2.3 (95% CI: 2.2-2.5) and 3.2 (3.0-3.3), respectively. RRs rose with increasing age at BBD diagnosis and remained elevated for at least 20 years after diagnosis. RRs were particularly high for a relatively small number of cancers occurring in the first few months after BBD diagnosis. CONCLUSIONS: Our findings accord well with those in other large studies, mostly done in the USA, in showing a sustained long-term cancer risk after BBD. They also demonstrate that known long-term risks of disease can be reliably identified from linked routine administrative hospital statistics. Most other studies omit cancers in the first few months after BBD. Such cases-presumably either misdiagnosed or miscoded-merit further study to determine whether in fact they include diagnoses of cancer that were initially missed

Best be(e) on low fat: linking nutrient perception, regulation and fitness

Preventing malnutrition through consuming nutritionally appropriate resources represents a challenge for foraging animals. This is due to often high variation in the nutritional quality of available resources. Foragers consequently need to evaluate different food sources. However, even the same food source can provide a plethora of nutritional and non‐nutritional cues, which could serve for quality assessment. We show that bumblebees, Bombus terrestris , overcome this challenge by relying on lipids as nutritional cue when selecting pollen. The bees ‘prioritised’ lipid perception in learning experiments and avoided lipid consumption in feeding experiments, which supported survival and reproduction. In contrast, survival and reproduction were severely reduced by increased lipid contents. Our study highlights the importance of fat regulation for pollen foraging bumblebees. It also reveals that nutrient perception, nutrient regulation and reproductive fitness can be linked, which represents an effective strategy enabling quick foraging decisions that prevent malnutrition and maximise fitness

Physiological mechanisms underlying the control of meal size in Manduca sexta larvae

Fifth stadium larvae of the tobacco hornworm, Manduca sexta (L.), ate larger meals than usual when they had been deprived of food for periods of time longer than the usual intermeal interval (c. 45 min). Meal size increased with time since the last meal until 180 min, when it was about 3 times normal. There was no evidence of a role for volumetric feedback from the gut in controlling meal size. Injections of a paraffin oil/wax mixture, or of petroleum jelly (Vaseline) into the foregut, midgut or rectum failed to decrease meal size. Cutting the recurrent nerve failed to alter meal size compared to sham-operated controls (although both groups took smaller meals than unoperated controls). By contrast, injections of an extract of soluble nutrients from the diet into the midgut inhibited feeding in some insects and reduced subsequent meal size in others. Appropriate controls showed that these effects were not due to the volumetric or osmotic effects of the injections. These results imply that nutrient feedback plays an important role in controlling meal size in Manduca caterpillars, while volumetric feedback is probably unimportant.W. A. Timmins and S. E. Reynold