Individual virgin females of two races of Podisma pedestris were mated sequentially with a male of each race in one or other reciprocal orders, giving four types of double matings. The embryos were karyotyped to determine the extent of each male's paternity. This gave an excess of racial homozygotes as well as showing a predominance of the first male's sperm in fertilization. This confirms the previous indication of assortative fertilization producing homogamy, and reveals first sperm precedence, which is rare in insects. There was some infertility and a biased sex ratio. The implications for the evolution of assortment, reproductive isolation, sperm competition, male-female conflict and mating strategies are discussed.
BackgroundExisting research points towards physical and mental health gains from housing improvements, but findings are inconsistent and often not statistically significant. The detailed characteristics and variability of housing improvement works are problematic and studies are often small, not experimental, with short follow-up times.MethodsA quasi-experimental design was used to assess the impact on physical health and mental health (using SF-12v2 Physical and Mental health component summary scales) of four types of housing improvement works—central heating, ‘Secured By Design’ front doors, fabric works, kitchens and bathrooms—both singly and in pairwise combinations. A longitudinal sample of 1933 residents from 15 deprived communities in Glasgow, UK was constructed from surveys carried out in 2006, 2008 and 2011. Sociodemographic characteristics and changes in employment status were taken into account.ResultsFabric works had positive associations with physical health (+2.09, 95% CI 0.13 to 4.04) and mental health (+1.84, 95% CI 0.04 to 3.65) in 1–2 years. Kitchens and bathrooms had a positive association with mental health in 1–2 years (+2.58, 95% CI 0.79 to 4.36). Central heating had a negative association with physical health (−2.21, 95% CI −3.74 to −0.68). New front doors had a positive association with mental health in <1 year (+5.89, 95% CI 0.65 to 11.14) and when provided alongside kitchens and bathrooms (+4.25, 95% CI 1.71 to 6.80). Gaining employment had strong associations with physical health (+7.14, 95% CI 4.72 to 9.55) as well as mental health (+5.50, 95% CI 3.27 to 7.73).ConclusionsFabric works may provide insulation benefits and visual amenity benefits to residents. Front doors may provide important security benefits in deprived communities. Economic regeneration is important alongside property-led regeneration.
Abstract. Local dispersal and philopatric behaviour of the alpine grasshopper, Podisma pedestris, were studied at two sites in the Alpes Maritimes using a new mark—release—resight technique featuring marking in situ, and multiple resighting without handling. The time‐consuming nature of the design was justified by the quantity and quality of the data yielded. Philopatry is defined independently of any concept of home range as a phenomenon by which movements over longer periods are less than would be expected by extrapolation of measures over shorter periods. By this definition, the grasshoppers are shown to exhibit philopatry. Nymphs comprise two heterogenous classes of those which move little and those which move considerable distances. Daily dispersal estimates were obtained from movements of 1055 nymphs and adults at one site, and of 593 adults at another. Differences are demonstrated in daily dispersal distances for age, sex and site combinations. Some differences in microhabitat preference were observed. The findings are compared with previous measurements of dispersal in this species, and the merits of the new technique are discussed.
A study of the variation in pattern and frequency of constitutive heterochromatin and nucleolar organizing regions of the X chromosomes of male Chorthippus parallelus grasshoppers in 25 populations within the Iberian peninsula requires us to revise our interpretation of the biogeography and evolutionary history of this species. Hybridization between the subspecies Cp erythropus and Cp parallelus, previously only known from populations in the Pyrenean cols, is shown to extend at least 400 km further into north‐west Spain. A novel X‐chromosome variant is described that appears to be close to fixation in 18 populations, mainly from the centre and south of Spain. Our findings indicate a possible independent origin for each of three distinct, nonderivative X variants present in Spain: the northern Cp erythropus and Cp parallelus variants, and a central‐southern Cp erythropus variant. The first two are distinguished by interstitial and distal C bands, respectively, whereas the central‐southern form has neither. This central‐southern form is probably the current representative of the ancestral Iberian X variant. The pattern of variation supports the hypotheses of multiple refugia for Iberian populations and that more hybrid zones exist between these chromosomal variants.
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