Evaluation of a novel triple-action adulticide containing a pyrethroid, macrocyclic lactone, and fatty acid against pyrethroid-resistant Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

Insecticide resistance in mosquito populations has long been recognized as a significant global public health challenge, motivating the development of new control chemistries. ReMoa Tri is a novel triple-action space spray that employs a different mode of action than traditional adult mosquito control formulations. It combines 3 components: fenpropathrin, a mixed-type I/II pyrethroid; abamectin, a macrocyclic lactone; and C8910, a patented fatty acid chain. As an ultra-low volume adulticide, ReMoa Tri has the potential to target mosquito species that are resistant to pyrethroid and organophosphate-based control materials. To determine whether ReMoa Tri effectively targets resistant mosquito species in Florida's Collier County, United States, we conducted ground-based field cage trials using field-caught pyrethroid-resistant Culex quinquefasciatus (Say) and Aedes aegypti (L.), of which the latter also displayed developing resistance to organophosphates. Trials were also conducted against the same mosquito populations with Merus 3.0, a pyrethrin-based adulticide used by the Collier Mosquito Control District. ReMoa Tri was effective against Collier's pyrethroid-resistant Cx. quinquefasciatus, resulting in more than 95% mortality in semifield cage trials by 24 h postapplication. Similarly, ReMoa Tri applications against Collier's pyrethroid-resistant Ae. aegypti resulted in 72%-89% mortality at 24 h postapplication and 74%-97% mortality at 48 h postapplication. This study represents the first field data on this novel space spray, and its findings shed light on the performance of ReMoa Tri against local mosquito populations that have developed resistance to currently available adulticides.

Detection of Aedes Scapularis In Southwestern Florida.

Aedes scapularis has recently been detected for the first time in southwestern Florida. During the course of research and surveillance activities by local mosquito control districts in 2020 and 2021, a total of 190 adult females were collected from 14 separate locations in Collier and Lee Counties. To date, Ae. scapularis has been found in 5 counties since its rediscovery in Florida in 2006. Its detection and likely northward expansion into Collier and Lee Counties from the southern Florida Peninsula is in line with ecological niche model predictions that found the environment of the Gulf Coast of southwestern Florida to be highly suitable for the species. Due to its potential ability to transmit both exotic and endemic pathogens such as Everglades virus and Dirofilaria immitis, understanding the range and distribution of Ae. scapularis should be a priority for Florida mosquito control and public health agencies.

Aedes Tortilis, Culex Declarator, and Culex Tarsalis: New County Records for Mosquito Species in Collier County, Florida.

Understanding the distribution of mosquito species is an important element of surveillance. This is especially true in Florida, where detections of nonnative mosquitoes have been increasing. Collier Mosquito Control District performs routine adult mosquito surveillance for operational purposes throughout the year. Here, we report records for 3 species collected in 2021 that had not been documented previously in Collier County, FL: Aedes tortilis, Culex declarator, and Cx. tarsalis. Specimens were initially identified based on morphology, then each species was confirmed by comparing the cytochrome c oxidase subunit I gene sequences to those of other related mosquito species. Although Ae. tortilis and Cx. declarator were collected at multiple sites, Cx. tarsalis was collected only once, making it unclear whether this species has established a permanent population within the county.

Culex (Phenacomyia) lactator (Diptera: Culicidae) in southern Florida, USA: a new subgenus and species country record.

The Culex subgenus Phenacomyia is a small and poorly studied group of three mosquito species native to the American tropics. Here, we report the first detections of established populations of Culex (Phenacomyia) lactator Dyar & Knab in three counties of southern Florida. Culex lactator was first detected in May 2018 in southern Miami-Dade County, and, at this locality, was collected in subsequent years from 2018 to 2022 as both adults and immatures. Larvae and adults were subsequently collected in 2022, ~175 km northwest of the initial locality at nine sites in Collier and Lee Counties. Identification of specimens collected in these counties as Cx. lactator is supported by molecular analysis and morphological characters of the adult female, male genitalia, and larva. The host associations and vector competence of Cx. lactator have not been extensively studied, and the public health implications, if any, of the addition of this species to Florida's mosquito fauna are unclear. These collections represent the first detections of Cx. lactator, or any Phenacomyia species, in the United States, adding to a trend in which detections of established populations of mosquito species from the American tropics in Florida appear to be increasing.

The Impact of Hurricane Irma on Our Community and the Collier Mosquito Control District's Mission.

The Collier Mosquito Control District, located in southwest Florida, is uniquely positioned in a subtropical environment between the Gulf of Mexico and Everglades National Park. The District's mission is focused on the control of disease vector and nuisance mosquitoes in Collier County, which is accomplished through integrated mosquito management. Hurricane Irma made landfall in the county on September 10, 2017, leaving in its wake tremendous property and infrastructure damage, and it also disrupted communications and airport operations. These factors greatly affected the District's operations and its ability to meet its mission. In addition, the lengthy loss of electrical power forced most residents outdoors, increasing their exposure to mosquitoes. From challenges in completing poststorm treatments to outdated policies that caught us off-guard, the event prompted a new hurricane policy and plan to ensure improved preparedness for the next natural disaster. The poststorm environment also provided a rich foundation for research into mosquito populations after tropical disturbances of this scale. Here we report the impact on the District's aerial mosquito control operations, changes to internal policies, and mosquito population abundance following Hurricane Irma.

Interactions between a fungal entomopathogen and malaria parasites within a mosquito vector.

BACKGROUND: Mosquitoes are becoming increasingly resistant to the chemical insecticides currently available for malaria vector control, spurring interest in alternative management tools. One promising technology is the use of fungal entomopathogens. Fungi have been shown to impact the potential for mosquitoes to transmit malaria by reducing mosquito longevity and altering behaviour associated with flight and host location. Additionally, fungi could impact the development of malaria parasites within the mosquito via competition for resources or effects on the mosquito immune system. This study evaluated whether co-infection or superinfection with the fungal entomopathogen Beauveria bassiana affected malaria infection progress in Anopheles stephensi mosquitoes. METHODS: The study used two parasite species to examine possible effects of fungal infection at different parasite development stages. First, the rodent malaria model Plasmodium yoelii was used to explore interactions at the oocyst stage. Plasmodium yoelii produces high oocyst densities in infected mosquitoes and thus was expected to maximize host immunological and resource demands. Second, fungal interactions with mature sporozoites were evaluated by infecting mosquitoes with the human malaria species Plasmodium falciparum, which is highly efficient at invading mosquito salivary glands. RESULTS: With P. yoelii, there was no evidence that fungal co-infection (on the same day as the blood meal) or superinfection (during a subsequent gonotrophic cycle after parasite infection) affected the proportion of mosquitoes with oocysts, the number of oocysts per infected mosquito or the number of sporozoites per oocyst. Similarly, for P. falciparum, there was no evidence that fungal infection affected sporozoite prevalence. Furthermore, there was no impact of infection with either malaria species on fungal virulence as measured by mosquito survival time. CONCLUSIONS: These results suggest that the impact of fungus on malaria control potential is limited to the well-established effects on mosquito survival and transmission behaviour. Direct or indirect interactions between fungus and malaria parasites within mosquitoes appear to have little additional influence.

Temperature variation makes ectotherms more sensitive to climate change.

Ectotherms are considered to be particularly vulnerable to climate warming. Descriptions of habitat temperatures and predicted changes in climate usually consider mean monthly, seasonal or annual conditions. Ectotherms, however, do not simply experience mean conditions, but are exposed to daily fluctuations in habitat temperatures. Here, we highlight how temperature fluctuation can generate 'realized' thermal reaction (fitness) norms that differ from the 'fundamental' norms derived under standard constant temperatures. Using a mosquito as a model organism, we find that temperature fluctuation reduces rate processes such as development under warm conditions, increases processes under cool conditions, and reduces both the optimum and the critical maximum temperature. Generalizing these effects for a range of terrestrial insects reveals that prevailing daily fluctuations in temperature should alter the sensitivity of species to climate warming by reducing 'thermal safety margins'. Such effects of daily temperature dynamics have generally been ignored in the climate change literature.