Objective: To examine the effects of increasing larval rearing temperatures on the resistance status of Trinidadian populations of Aedes aegypti to organophosphate (OP) insecticides.
Methods: In 2007-2008, bioassays and biochemical assays were conducted on A. aegypti larvae collected in 2006 from eight geographically distinct areas in Trinidad (Trinidad and Tobago). Larval populations were reared at four temperatures (28 ± 2ºC, 32ºC, 34ºC, and 36ºC) prior to bioassays with OP insecticides (fenthion, malathion, and temephos) and biochemical assays for esterase enzymes.
Results: Most larval populations reared at 28 ± 2ºC were susceptible to fenthion (>98% mortality) but resistant to malathion and temephos (< 80% mortality). A positive association was found between resistance to OP insecticides and increased activities of α- and β-esterases in larval populations reared at 28 ± 2ºC. Although larval populations reared at higher temperatures showed variations in resistance to OPs, there was a general increase in susceptibility. However, increases or decreases in activity levels of enzymes did not always correspond with an increase or decrease in the proportion of resistant individuals reared at higher temperatures.
Conclusions: Although global warming may cause an increase in dengue transmission, based on the current results, the use of insecticides for dengue prevention and control may yet be effective if temperatures increase as projected.
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http://dx.doi.org/10.1590/s1020-49892012000700001 | DOI Listing |
Front Physiol
December 2024
Department of Zoology, Acharya Narendra Dev College, University of Delhi, New Delhi, India.
Introduction: , the vector of multiple arboviral diseases, is a prime health concern worldwide. The surge in borne diseases emphasizes the urgent need for efficient vector control measures. Synthetic pesticides used traditionally, however, present environmental concerns and issues like resistance development, causing the use of higher chemical doses.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
Spodoptera litura (Fabricius) is a major polyphagous pest of global relevance due to the damage it causes to various crops. Chlorpyrifos (CPF) is generally used by farmers to manage S. litura, however, its widespread use has resulted in the development of insecticide resistance.
View Article and Find Full Text PDFPLoS One
December 2024
Invasive Insect Biocontrol and Behavior Laboratory, USDA-ARS, Beltsville, Maryland, United States of America.
The bagrada bug, Bagrada hilaris (Burmeister), is an emerging agricultural pest in the Americas, threatening agricultural production in the southwestern United States, Mexico and Chile, as well as in the Old World (including Africa, South Asia and, more recently, Mediterranean areas of Europe). Substantive transcriptomic sequence resources for this damaging species would be beneficial towards understanding its capacity for developing insecticide resistance, identifying viruses that may be present throughout its population and identifying genes differentially expressed across life stages that could be exploited for biomolecular pesticide formulations. This study establishes B.
View Article and Find Full Text PDFTrop Med Infect Dis
December 2024
ICMR-Vector Control Research Centre Field Station, No. 4, Sarojini Street, Chinna Chokkikulam, Madurai 625 002, Tamil Nadu, India.
Malaria remains a significant public health problem in India. Although temperature influences Anopheline mosquito feeding intervals, population density, and longevity, the reproductive potential of the Plasmodium parasite and rainfall influence the availability of larval habitats, and evidence to correlate the impact of climatic factors on the incidence of malaria is sparse. Understanding the influence of climatic factors on malaria transmission will help us predict the future spread and intensification of the disease.
View Article and Find Full Text PDFmBio
December 2024
Department of Biology, San Diego State University, San Diego, California, USA.
Unlabelled: Diverse marine animals undergo a metamorphic larval-to-juvenile transition in response to surface-bound bacteria. Although this host-microbe interaction is critical to establishing and maintaining marine animal populations, the functional activity of bacterial products and how they activate the host's metamorphosis program has not yet been defined for any animal. The marine bacterium stimulates the metamorphosis of a tubeworm called by producing a molecular syringe called metamorphosis-associated contractile structures (MACs).
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