WILLIAMS, P. H., 1989. Why are there so many species of bumble bees at Dungeness? Dungeness is unique in the British Isles in that it has more species of bumble bees than any other locality. Three ideas about what governs the number of species at a locality are examined by locking at patterns of flower visits at Dungeness in comparison with those at Shoreham, a species-poor locality also in Kent. The species of bumble bees that are present at Dungeness but absent from Shoreham show no ...

A global collection of 123 putative isolates of Fusarium oxysporum from crucifers was examined for pathogenicity, isozyme polymorphism, and vegetative compatibility. Of these isolates, 103 were found to be pathogenic on one or more of six differential crucifer cultivars. Three patterns of isozyme polymorphism (electrophoretic types) were found and by means of a nitrate reductase complementation test, three major vegetative compatibility groups were identified that could differentiate ...

Abstract: It has been suggested that using complementarity to identify networks of important areas for conserving biodiversity may preferentially select areas within the margins of species ranges. We tested this idea by examining the location of complementarity hotspots in relation to two measures of range core-periphery. The first measures patterns of aggregation among records within each species' range to identify areas within the core (i.e., areas with aggregated distributions) and ...

Biogeographic regions are widely regarded as real entities, or at least as useful summaries of the complex patterns of spatial concordance among species. The problem is that, whereas some parts of the transition zones between regions may be strong and abrupt, other parts of the same zones may be weak or broad, so that the corresponding parts of border lines drawn on maps, although convenient, are arbitrary constructs. One approach to investigating transition zones ascribes values to the ...

Selection for resistance to Plasmodiophora brassicaeWor. in oriental groups of Brassica rapa L.Two hundred and sixty-five cultivars of leafy, oriental bassicas were tested for resistance to 18 collections of Plasmodiophora brassicae, the causal agent of clubroot. The tests were conducted in the greenhouse at low and high level inoculum concentrations. Eleven cultivars of B. rapa pe-tsai, five cultivars of B. rapa pak-choy and three cultivars of B. rapa choy-sum consistently segregated ...

Meralgia paresthetica is a syndrome of pain or dysesthesia, or both, in the anterolateral thigh caused by entrapment or neurinoma formation of the lateral femoral cutaneous nerve. Conservative treatment was successful in relieving symptoms in 91% of 277 patients with this syndrome; however, 24 patients required surgical treatment for intractable symptoms. Although neurolysis with transposition is the most common procedure, sectioning of the lateral femoral cutaneous nerve was performed ...

Area-selection methods have recently gained prominence in conservation biology. A typical problem is to identify the minimum number of areas required to represent all species over some geographic region. Iterative heuristic methods have been developed by conservation scientists to solve these problems, although the solutions cannot be guaranteed to be optimal. Although optimal solutions can often be found, heuristics continue to be popular as they are perceived to be faster and more ...

Resistance to gummy stem blight (Didymella bryoniae) was not detected among 1208 cucumber lines of diverse origin when cotyledons of four-day-old seedlings were inoculated with an aqueous suspension of 5000 spores of D. bryoniae delivered to freshly crushed tissue, followed by 48 h incubation at 20°C and 100% RH in the dark. Among 49 lots evaluated for gummy stem blight in the field, cv. Homegreen #2 and Pl 200818 from Burma were resistant. Earliness in fruit maturity was positively ...

ABSTRACT. 1Analysis of surveys of bumble bee distribution among 2 km grid-squares in Kent revealed that some species are nearly ubiquitous among localities and abundant within each. For these ubiquitous species, Kent is near the middle of their latitudinal ranges.2The other species have very restricted distributions among localities and are less abundant where they occur. For each of these local species, Kent is near the margin of its latitudinal range.3The areas to which the local ...

The Tibetan plateau and its immediately surrounding mountains include the greatest hotspot of diversity worldwide for bumblebees, which are among the most important pollinators in temperate ecosystems. We make the first quantitative description of variation in the species composition of alpine social bumblebee faunas across the Tibetan plateau, for 44 species in 124 of the 307 one-degree grid cells. Data were compiled from field surveys, published sources and museum collections. Sampling ...

Black rot lesion development in cabbage leaves was correlated with accumulation of plugging material in the xylem vessels as Xanthomonas campestris multiplied and spread. Plug formation preceded a partial disorganization of the xylem, and spillage of bacteria from the vessels. The movement of eosin and

32

PO

4

3−

was blocked within the vessels, and plugs caused water ...

Abstract

Records of bumble bees from four collecting trips (1977, 1978, 1988, and 1994) in northern Britain show apparent changes in the incidences of two species. Until 1988,

Bombus muscorum

(Linnaeus) and

Bombus pascuorum

(Scopoli) were found in the counties of Cumbria, Durham, and North Yorkshire. Only

B

.

...