Entomology Research Today is a free monthly online journal that collates and summarizes the latest research about Entomology, including details on insects, parasites, diseases.

Impact of urban agriculture on malaria vectors in Accra, Ghana.

Klinkenberg E, McCall P, Wilson MD, Amerasinghe FP, Donnelly MJ

International Water Management Institute (IWMI), West Africa Office, Ghana. klinkenberge@kncvtbc.nl

To investigate the impact of urban agriculture on malaria transmission risk in urban Accra larval and adult stage mosquito surveys, were performed. Local transmission was implicated as Anopheles spp. were found breeding and infected Anopheles mosquitoes were found resting in houses in the study sites. The predominant Anopheles species was Anopheles gambiae s.s.. The relative proportion of molecular forms within a subset of specimens was 86% S-form and 14% M-form. Anopheles spp. and Culex quinquefasciatus outdoor biting rates were respectively three and four times higher in areas around agricultural sites (UA) than in areas far from agriculture (U). The annual Entomological Inoculation Rate (EIR), the number of infectious bites received per individual per year, was 19.2 and 6.6 in UA and U sites, respectively. Breeding sites were highly transitory in nature, which poses a challenge for larval control in this setting. The data also suggest that the epidemiological importance of urban agricultural areas may be the provision of resting sites for adults rather than an increased number of larval habitats. Host-seeking activity peaked between 2-3 am, indicating that insecticide-treated bednets should be an effective control method.

Published 13 August 2008 in Malar J, 7: 151.
Full-text of this article is available online (may require subscription).

Articles on Entomology published 12 August 2008:

Symbionts, including pathogens, of the predatory mite Metaseiulus occidentalis: current and future analysis methods.   Exp Appl Acarol.

Metaseiulus (= Typhlodromus or Galendromus) occidentalis (Nesbitt) (Acari: Phytoseiidae) is an effective natural enemy of pest mites in a variety of crops around the world, although it is considered to be endemic in the western USA. A broad understanding of much of its biology, ecology, behavior, and genetics has been obtained over the past 60 years, but the role(s) symbionts play, which includes pathogens and other microorganisms, remains to be resolved fully. Until molecular tools became ... [Abstract] [Full-text]

Articles on Entomology published 11 August 2008:

EXPERIMENTAL EVOLUTION OF THE GENETIC LOAD AND ITS IMPLICATIONS FOR THE GENETIC BASIS OF INBREEDING DEPRESSION.   Evolution.

The degree to which, and rapidity with which, inbreeding depression can be purged from a population has important implications for conservation biology, captive breeding practices, and invasive species biology. The degree and rate of purging also informs us regarding the genetic mechanisms underlying inbreeding depression. We examine the evolution of mean survival and inbreeding depression in survival following serial inbreeding in a seed-feeding beetle, Stator limbatus, which shows substantial ... [Abstract] [Full-text]

Cold hardiness of Apteropanorpa tasmanica Carpenter (Mecoptera: Apteropanorpidae).   J Insect Physiol, 54(7): 1148-56.

There are very few investigations of cold hardiness in native Australian insects, and no such studies on insects from Tasmania. The Apteropanorpidae is a family of wingless Mecoptera endemic to Tasmania, comprising four described species that can be active in winter. In this study, we used infrared video thermography to investigate the physiological and behavioural responses of Apteropanorpa tasmanica to fast (0.3 degrees Cmin(-1)) and slow (0.03 degrees Cmin(-1)) rates of temperature reduction ... [Abstract] [Full-text]

Effects of Bacillus thuringiensis toxin Cry1Ac and Beauveria bassiana on Asiatic corn borer (Lepidoptera: Crambidae).   J Invertebr Pathol.

In this study, interactions between Cry1Ac, a toxic crystal protein produced by Bacillus thuringiensis (Berliner), and Beauveria bassiana on the mortality and survival of Ostrinia furnacalis was evaluated in the laboratory. The results showed that Cry1Ac is toxic to O. furnacalis. Not only were larval growth and development delayed, but pupation, pupal weight and adult emergency also decreased when larvae were fed on artificial diet containing purified Cry1Ac toxin. When third instars O. ... [Abstract] [Full-text]

Stink bug interaction with host plants during communication.   J Insect Physiol, 54(7): 1113-24.

In solitary plant-dwelling stink bug species, success depends crucially on efficient mate location and recognition, mediated by signals transmitted through the plant. All stink bugs investigated so far communicate with species and sex-specific narrow-band calling and courtship song signals produced by abdomen vibration. Calling songs of lower specificity are characterized by readily repeated units emitted with regular repetition rate from the same place on a plant, while courtship songs take ... [Abstract] [Full-text]

Attraction of female Culex quinquefasciatus Say (Diptera: Culicidae) to odors from chicken feces.   J Insect Physiol, 54(7): 1184-92.

Odors from fresh chicken feces in water elicited upwind flight of host-seeking female Culex quinquefasciatus mosquitoes in a dual-choice olfactometer. Acidification of the slurry of chicken feces and water resulted in increased attraction, whereas alkaline slurries of chicken feces and water controls did not attract female mosquitoes. This is the first reported example of avian fecal odor eliciting upwind flight of female mosquitoes. Headspace odors from acidified slurries were sampled using ... [Abstract] [Full-text]

Neuroanatomical investigation of the gonadotrophin-releasing hormone 1 system in the seasonally breeding Cape dune mole-rat, Bathyergus suillus.   Brain Res Bull.

The gonadotrophin-releasing hormone 1 (GnRH1) system has been investigated immunohistochemically in Cape dune mole-rats (Bathyergus suillus), subterranean rodents that normally display severe aggression towards conspecifics. These animals breed seasonally and show a reduced mean plasma level of luteinising hormone during the non-breeding season. GnRH1-immunoreactive (ir) cell bodies and processes are found in the septal/preoptic area and the mediobasal hypothalamus; the cell bodies are found in ... [Abstract] [Full-text]

Conformational aspects and hyperpotent agonists of diapause hormone for termination of pupal diapause in the corn earworm.   Peptides.

Diapause hormone (DH) is a peptide well known to induce embryonic diapause in the commercial silkmoth Bombyx mori. More recently, this same neuropeptide was reported to break diapause in pupae of the agriculturally important Heliothis/Helicoverpa complex. In this study we examine the efficacy and potency of a select group of structural analogs of the native hormone in Helicoverpa zea and report the structures of several analogs that are considerably more potent than DH in breaking diapause. ... [Abstract] [Full-text]

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