The mechanisms by which natural populations of vector mosquitoes cope with daily and seasonal fluctuations in temperature are poorly understood. We examined the effect of water temperature on expression of stress and immune-related genes in Aedes aegypti larvae. Aedes aegypti 3rd instars were exposed for 24 h to one of 7 constant temperatures (10°C, 15°C, 20°C, 25°C [control], 32°C, 36°C, or 40°C) and expression of antimicrobial peptides (cecropin, defensin), transferrin, and heat shock proteins (HSP70 and HSP83) quantified by real-time reverse-transcriptase polymerase chain reaction. Cecropin, defensin, and transferrin were overexpressed at 36°C and underexpressed at 15°C and 32°C. HSP83 was overexpressed at 10°C and 40°C and underexpressed at 20°C, while HSP70 was underexpressed at 15°C, 32°C, and 36°C. These findings suggest that antimicrobial peptides can serve as biomarkers of thermal stress and that HSP83 may buffer mosquito larvae against extreme temperatures.

It is important to obtain frequent measurements of the abundance, distribution, and seasonality of mosquito vectors to determine the risk of disease transmission. The number of cases of dengue infection has increased in recent years on Penang Island, Malaysia, with recurring epidemics. However, ongoing control attempts are being critically hampered by the lack of up-to-date information regarding the vectors. To overcome this problem, we examined the current situation and distribution of dengue vectors on the island. Residences throughout the urban, suburban, and rural areas were inspected through wet and dry seasons between February 2009 and February 2010. Two vectors were encountered in the survey, with Aedes aegypti present in especially high numbers mostly in urban areas. Similar observations were noted for Ae. albopictus in rural areas. The former species was more abundant in outdoor containers, while the latter showed almost equivalent abundance both outdoors and indoors. The dengue virus was active in both urban and rural areas, and the number of cases of infection was higher in areas where Ae. aegypti was predominant. The abundance of immature Ae. albopictus was positively correlated with rainfall (r²  =  0.461; P < 0.05), but this was not the case for Ae. aegypti. For both species, the size of immature populations tended to increase with increasing intensity of rain, but heavy rains resulted in population loss. In addition to updating data regarding the larval habitats and locations (outdoors and indoors), this study highlighted the importance of spatial vector control stratification, which has the potential to reduce costs in control programs.

This work reports droplet-size data measured as part of a collaborative testing program between the US Department of Agriculture, Agricultural Research Service, and the US Navy, Navy Entomological Center for Excellence. This is an ongoing relationship that seeks to test new and revised spray technologies that may potentially be used by deployed personnel. As new equipment comes to market or when existing equipment is modified they are all integrated into this annual testing. During the 2011 equipment evaluations, 24 sprayers were operated across their range of available settings (pressure and flow rate), using both water and oil solutions. Droplet-size data as measured with laser diffraction ranged from 4 to 223 µm (volume median diameter). Generally, as the spray rate increased, droplet size increased, and as the pressure increased at a given same spray rate, droplet size decreased. This information allows users to set up and operate these sprayers in a manner such that a particular droplet size is applied optimizing efficiency and efficacy of applications.

The 22nd Annual Latin American Symposium presented by the American Mosquito Control Association (AMCA) was held as part of the 78th Annual Meeting in Austin, TX, in February 2012. The principal objective, as for the previous 21 symposia, was to promote participation in the AMCA by vector control specialists, public health workers, and academicians from Latin America. This publication includes summaries of 21 presentations that were given orally in Spanish or presented as posters by participants from Mexico, Colombia, Venezuela, and the USA. Topics addressed in the symposium included surveillance, chemical control, insecticide resistance, and genetics associated with Aedes aegypti; food sources and control of Culex; taxonomy, surveillance, and control of Anopheles vectors of malaria; and studies of dengue virus and Leishmania.

Eleven mosquito species, namely Aedes hastatus, Ae. fulvus, Coquillettidia albicosta, Cq. juxtamansonia, Culex aliciae, Cx. delpontei, Cx. oedipus, Cx. pedroi, Mansonia flaveola, Uranotaenia leucoptera, and Wyeomyia oblita, are recorded for the first time from northwestern Argentina. In addition, 3 species, Cx. brethesi, Limatus durhami, and Ur. nataliae, are reported for the first time from Salta Province. These records extend the geographical distribution of these 3 species to Salta Province. This study also extends the geographical distributions of Cq. nigricans, Cx. chidesteri, and Ma. humeralis to Jujuy Province and of Ae. meprai, Ae. milleri, Ae. oligopistus, Cx. brethesi, Cx. fernandezi, and Cx. tatoi to Tucumán Province.

During south-west monsoon season, rubber plantations in Kerala have been found to provide ideal conditions for the proliferation of mosquitoes. In a study conducted from June 2005 to September 2010 in Kannur, Wayanad, and Kozhikode districts, 12 species of mosquitoes in 6 genera—Aedes, Armigeres, Culex, Heizmannia, Toxorhynchites, and Verrallina—were found to breed in rain water-filled cups used for collecting rubber latex. The only vector species found was Aedes albopictus, known for its ability to transmit dengue and chikungunya. The combinations of species found associated in the latex cups is also presented.

We found 4 species of mosquitoes bearing eggs of the human botfly, Dermatobia hominis, in the Reserva Municipal de Trabiju, Pindamonhangaba, São Paulo, Brazil. The mosquitoes were simultaneously collected in landing–biting catches by 2 collectors. From a total of 6,902 specimens collected from January through April 2010, the 15 females carrying D. hominis eggs belonged to Aedes scapularis, Limatus durhamii, Onirion personatum, and Wyeomyia confusa. The first 3 species are new reports of phoresy among mosquitoes and the human botfly.

Successful malaria management in Mali includes the use of pyrethroids and insecticide-treated nets (ITNs) for mosquito control; however, management is threatened by the spread of insecticide resistance detected via the knockdown resistance (kdr) allele. In a preliminary study, we compared the knockdown times of Anopheles gambiae from Mali using a novel ITN bioassay and the World Health Organization (WHO) bottle bioassay. Additionally, the frequency and relationship between kdr genotypes, molecular forms, and pyrethroid resistance were analyzed. The S molecular form was predominant and accounted for 76% of the assayed population. Both kdr resistant alleles, West Africa resistant (kdr-w) and East Africa resistant (kdr-e), were observed. There was no significant difference in knockdown time based on kdr genotype or molecular form of individual mosquitoes, but mosquitoes in the ITN bioassay homozygous for the kdr-w allele were knocked down significantly faster than those in the WHO bottle bioassay. The ITN bioassay provides an additional indicator of insecticide efficacy because ITNs, frequently used within homes, are the most common form of vector control and malaria prevention, and the ITN bioassays can evaluate seasonal field effects.

Synthetic blends of chemicals identified previously from human skin emanations were evaluated against mosquito and biting fly populations at the Lower Suwannee Wildlife Refuge near Cedar Key, FL. Mosquito Magnet™-Experimental traps were baited with the Red (400 ml acetone:10 ml 1-hexen-3-ol:10 ml 1-octen-3-ol), Blue (400 ml acetone:1 g/liter lactic acid:20 ml glycolic acid), or Green blend (400 ml acetone:1.5 g/liter lactic acid:20 ml dimethyl disulfide) plus CO₂ or with CO₂ alone (control). A relative index of efficacy was determined by dividing each mean blend trap catch by the mean control trap catch. Five mosquitoes (Aedes infirmatus, Ae. taeniorhynchus, Ae. triseriatus, Anopheles crucians, and Culex nigripalpus), 2 ceratopogonid (Culicoides floridensis and C. furens), and 1 tabanid (Diachlorus ferrugatus) and phlebotomine (Lutzomyia shannoni) species were trapped. The Red blend CO₂ treatment significantly increased collections of Ae. taeniorhynchus (3.4×), An. crucians (2.8×), total mosquitoes (2.7×), C. furens (17.6×), and L. shannoni (10.8×) compared with control traps. Traps baited with either the Blue or Green blends generally captured fewer insects than traps baited with the other 2 treatments. However, traps baited with the Green blend caught 7× as many C. furens as the control traps. Responses clearly varied according to species; therefore, “one size does not fit all” when it comes to attractant blends.

Approximately 800 species of phlebotomine sand flies, many of which are vectors of Leishmania, have been described. Besides morphological similarities within groups, the occurrence of anomalies within a species may lead to an erroneous description of new species. This paper describes one phlebotomine sand fly, Evandromyia evandroi, with a symmetrical bilateral anomaly in the number of spines on the gonostyle. In this specimen, the anomalous spine is located in the external region of gonostyle, inserted between the upper external and the lower external spines. It is important to document morphological anomalies, so as to avoid erroneous sand fly identifications.

The insecticidal activity of 4 mosquito coils containing pyrethroid ester insecticides and 1 mosquito coil containing 15% citronella oil was evaluated against adult female Anopheles albimanus, Aedes albopictus, and Culex quinquefasciatus. Two of the pyrethroid mosquito coils containing 0.08% meperfluthrin showed the strongest insecticidal activity, and all 4 pyrethroid coils produced significantly higher mortality than the citronella coil across all 3 test species.

Black fly suppression programs are conducted across a wide range of environmental conditions, targeting a variety of pest species with diverse life histories. Operational applications of Vectobac® 12AS (Bacillus thuringiensis subsp. israelensis) were conducted during times characterized by water temperature and turbidity extremes. Applications were conducted in the Yellow River in central Wisconsin targeting Simulium annulus and S. johannseni when water temperatures were 1–2°C. Applications were conducted in the Green River in western North Carolina targeting the S. jenningsi group after a rain event, when portions of the treatment zone experienced turbidities of 276 nephelometric turbidity units. Excellent larvicidal activity was observed in both programs, with 97% mortality or greater being observed at distances over 5 km downstream of a treatment site. Mortality data for larval black flies in 2 operational suppression programs conducted in 2011 demonstrated a negligible effect of near-freezing water temperatures and exceptionally high turbidity on Bti activity.