the seasonal abundance patterns of the cotton aphid, aphis gossypii glover, in cotton fields at gorgan in northern iran were studied during two growing seasons of 2002 and 2003. the spatial distribution of different developmental stages and morphs of the aphid was described by fitting data to poisson (random) and negative binomial (aggregated) dis-tributions, and calculating the dispersion indi...

Seasonal environmental changes have the potential to influence the genetic structure of species with a short generation time, such as Drosophila. We previously found the seasonal change in linkage disequilibrium (LD) between the chemoreceptor (Cr) genes in a local Japanese population (Kyoto [KY]). This could be caused by fluctuation in the population size or selection in temporally heterogeneou...

Theory shows that fluctuation of environmental conditions can produce temporal niches for inferior competitors that mitigate effects of interspecific competition and facilitate long-term persistence of poor competitors. In south Florida, the mosquitoes Aedes albopictus and Aedes aegypti often co-occur in water-filled containers despite A. albopictus being competitively superior to A. aegypti. W...

Capybaras (Hydrochoerus hydrochaeris) are widely distributed in the Neotropics, living in both natural and anthropogenic habitats. In the present study, we monitored the fluctuating capybara population at the Campus "Luiz de Queiroz", University of São Paulo, in Piracicaba, Southeastern Brazil from 1998 to 2000. To assess population fluctuation and growth rates, we used an abundance index based...

Recently, it is required to investigate the spatial distribution of vegetation in urban areas on a regional scale for not only the improvement of urban environment but also the conservation of ecosystem. In addition, the seasonal fluctuation of vegetation should be also analyzed because the vegetation distribution can be used for urban landscape management. The purpose of this study is to analy...

Seasonally driven cycles of incidence have been consistently observed for a range of directly transmitted pathogens. Though frequently observed, the mechanism of seasonality for directly transmitted human pathogens is rarely well understood. Despite significant annual variation in magnitude, measles outbreaks in Niger consistently begin in the dry season and decline at the onset of the seasonal...

in this investigation an attempt has been made to study the species composition, distribution and seasonal fluctuation of acarine community (arachnida: acari) in two undisturbed and well-vegetated plots located within padmaja naidu himalayan zoolo-gical park, darjeeling, india. the study continued for three consecutive years (january to december 1999–2001) revealed the presence of 10 acarine ge...

abstract myzus persicae sulzer is one of the serious pests in potato fields which has the ability of transmitting several viruses to the potato crop. throughout summer of 2008, field studies were carried out in ardabil to evaluate the seasonal population fluctuation of this aphid on 10 potato cultivars: granola, satina, moren, aozonia, cosima, agria, cosmos, kondor, diamant and savalan. density...