Biology, Ecology, and Feeding Behavior of Mosquitoes in Connecticut John Shepard Center for Vector Biology and Zoonotic Diseases The Connecticut Agricultural Experiment Station New Haven, CT Mosquito Life Cycle Type of Habitat 2 – 8+ • Temporary WEEKS • Pools, depressions, containers • Permanent • Swamps, marshes Type of Egg • Single (usually desiccation resistant) • Raft (laid on water) Seasonal Abundance (Phenology) Generations per year • Single 4 Instars • Multiple 7 – 14 DAYS Feeding Behavior • Females only (Temperature Dependent) Connecticut Mosquitoes 48 species documented in 2005 • Dichotomous Keys • 4th instar larvae • Adults Species Descriptions • Larvae • Adults • County Records • Larval Habitat • Overwintering Stage • Host Preference • Virus Isolates • Phenology Available as PDF 54 species documented as of 2018 www.ct.gov/caes Bulletin 996 Vectors • Maintenance or Amplifying • “Bridge” – transmit from vertebrate host to human, horse, etc. Mike Thomas, CAES Nuisance • Primarily Seek Blood from Mammals • Occasionally Infected with WNV, EEE • Seasonal Abundance Important Mosquito-Borne Virus Cycle Maintenance Cycle Transmission Cycle Incidental Infection Amplification Cycle “Bridge” Virus Mosquito Vertebrate Host Culex pipiens and Culex restuans • Main vector of West Nile virus (WNV) Maintenance and Amplification • Cx. pipiens = Urban and Suburban habitats • Cx. restuans = Suburban and Rural habitats • Egg Rafts • High organic content • “Containers”, Temporary pools • Multiple generations per year • Peak numbers in early-mid summer • Primarily feed on BIRDS • Occasionally on mammals Arbovirus Isolates Culex pipiens: WN (1,647), EEE (10) Culex restuans: WN (330), EEE (3), JC (1) Culex pipiens and Culex restuans • Larvae and pupae are found in a variety of habitats Culex pipiens and Culex restuans • Adults appear similar • can be distinguished Culex pipiens Mike Thomas, CAES Culex restuans Culex pipiens and Culex restuans Average Culex pipiens per Gravid Trap 45 40 2018 12 Year Mean 35 30 25 20 15 10 5 Average Mosquitoes Average 0 30 Average Culex restuans per Gravid Trap 25 Overwinters as 20 Mated Female 15 10 5 0 6/3-6/9 7/1-7/7 9/2-9/8 5/27-6/2 7/8-7/14 7/29-8/4 8/5-8/11 8/26-9/1 9/9-9/15 6/10-6/16 6/17-6/23 6/24-6/30 7/15-7/21 7/22-7/28 8/12-8/18 8/19-8/25 9/16-9/22 9/23-9/29 9/30-10/6 10/7-10/13 Week Culiseta melanura • Main vector of Eastern Equine Encephalitis (EEE) Maintenance and Amplification • Atlantic white cedar, red maple swamps • Egg Rafts • Underground “crypt” habitat, formed by tree roots • Sphagnum moss mats • 2 -3 generations per year • Peak numbers in mid summer • Primarily feed on BIRDS • Occasionally on mammals Arbovirus Isolates WN (108), EEE (264), JC (2) Culiseta melanura Mike Thomas, CAES # Mosquitoes 10 15 20 25 30 35 0 5 5/27-6/2 6/3-6/9 6/10-6/16 6/17-6/23 6/24-6/30 Culiseta melanura 7/1-7/7 7/8-7/14 melanura Culiseta Culiseta melanura 7/15-7/21 2018 7/22-7/28 3 Generations 7/29-8/4 21 Year Mean Week per Light Trap 8/5-8/11 8/12-8/18 8/19-8/25 8/26-9/1 9/2-9/8 9/9-9/15 Overwinter as 9/16-9/22 Larvae 9/23-9/29 9/30-10/6 10/7-10/13 10/14-10/20 Culex salinarius • Bridge Vector of West Nile virus (WNV) Transmission to Humans and Horses • Egg rafts laid on water in brackish and freshwater habitats • Shallow pools associated with Phragmites sp. • Multiple generations per year • Generalist Feeder • Obtains blood from many bird and mammal species Arbovirus Isolates WN (166), EEE (12), JC (3) Culex salinarius Mike Thomas, CAES Roger Wolfe, CT DEEP Roger Wolfe, CT DEEP UConn, CLEAR # Mosquitoes 10 15 20 25 30 35 40 45 50 0 5 5/27-6/2 6/3-6/9 6/10-6/16 6/17-6/23 6/24-6/30 Culexsalinarius 7/1-7/7 7/8-7/14 Culex salinarius Culex 7/15-7/21 2018 7/22-7/28 7/29-8/4 Date per Light Trap 8/5-8/11 21 Year Mean 8/12-8/18 8/19-8/25 8/26-9/1 9/2-9/8 Mated Female Overwinters as 9/9-9/15 9/16-9/22 9/23-9/29 9/30-10/6 10/7-10/13 10/14-10/20 Coquillettidia perturbans • Bridge Vector of Eastern Equine Encephalitis (EEE) Transmission to Humans and Horses • Single eggs laid directly on water • Larvae attach to aquatic vegetation in freshwater habitats • One extended generation per year • Generalist Feeder Arbovirus Isolates 2012 MA WN (7), EEE (4), JC (22), 7 human EEE cases 62 (+) pools from Cq. perturbans Coquillettidia perturbans www.bio.brandeis.edu NJMCA Tom Murray, bugguide.net # Mosquitoes 100 150 200 250 300 350 50 0 5/27-6/2 6/3-6/9 6/10-6/16 Coquillettidia 6/17-6/23 6/24-6/30 7/1-7/7 Coquillettidia perturbans 7/8-7/14 7/15-7/21 7/22-7/28 2018 7/29-8/4 Date 21 Year Mean 8/5-8/11 perturbans per Light Trap 8/12-8/18 8/19-8/25 8/26-9/1 9/2-9/8 Overwinter as 9/9-9/15 9/16-9/22 Larvae 9/23-9/29 9/30-10/6 10/7-10/13 10/14-10/20 “Floodwater” Species Ae. vexans • Primarily Nuisance mosquitoes • Desiccation-resistant eggs • Larvae develop in a variety of transient water habitats Oc. trivittatus • Multiple generations per year; RAINFALL dependent • Primarily Feed on Mammals • Occasionally on Birds Ps. ferox Arbovirus Isolates Aedes vexans = WN (18), EEE (15), JC (16) Bugguide.net Ochlerotatus trivittatus = WN (4), EEE (9), JC (19) Psorophora ferox = WN (5), EEE (2), JC (1) “Floodwater” Species Over 11,000 Ps. ferox & Ae. vexans Sept. 22, 2011 # Mosquitoes 10 20 30 40 50 60 70 0 5/27-6/2 6/3-6/9 6/10-6/16 6/17-6/23 “Floodwater” Species “Floodwater” 6/24-6/30 7/1-7/7 7/8-7/14 Aedes vexans Aedes 7/15-7/21 2018 7/22-7/28 7/29-8/4 per Light Trap Date 8/5-8/11 21 YearMean 8/12-8/18 8/19-8/25 8/26-9/1 9/2-9/8 9/9-9/15 Overwinter as 9/16-9/22 9/23-9/29 Eggs 9/30-10/6 10/7-10/13 10/14-10/20 “Vernal Pool” and “Snow-pool” Species • Nuisance mosquitoes • Most diverse group of mosquitoes in CT • Some potential to transmit WNV and EEE • Jamestown Canyon isolated frequently • Eggs are desiccation resistant Sean McCann, Bugguide.net • Larvae develop in a wide variety of seasonal freshwater habitats • Major generation in spring • Peak abundance in early summer • Some species with 2-3 generations Tom Murray, Bugguide.net • Strong Mammalian Association • Occasionally on Birds “Vernal Pool” and “Snow-pool” Species Arbovirus Isolates Oc. canadensis = WN(10), EEE(32), JC(118) 2-3 Ae. cinereus = WN(13), EEE(13), JC(12), LAC (2) Generations Oc. sticticus = WN(2), EEE(1), JC(25), Oc. abserratus = JC (51) Oc. aurifer = JC (51) Oc. excrucians = JC (15) 1 Generation Oc. provocans = JC (20) Oc. stimulans = WNV (2), JC (22), Oc. thibaulti = JC(2) “Vernal Pool” and “Snow-pool” Species # Mosquitoes 10 15 20 25 30 35 40 0 5 # Mosquitoes 0 1 1 2 # Mosquitoes2 3 3 4 4 5 “Vernal Pool” and “Snow and Pool” “Vernal 10 15 20 25 30 35 40 0 5 5/27-6/25/27-6/2 5/27-6/2 6/3-6/96/3-6/9 6/3-6/9 6/10-6/166/10-6/16 6/10-6/16 6/17-6/236/17-6/23 6/17-6/23 6/24-6/30 6/24-6/30 6/24-6/30 7/1-7/7 7/1-7/7 7/1-7/7 stimulans Ochlerotatus 7/8-7/14 7/8-7/14 abserratus Ochlerotatus 7/8-7/14 cinereus Aedes 7/15-7/21 7/15-7/21 7/15-7/21 2018 7/22-7/28 2018 7/22-7/28 2018 7/22-7/28 Generations 3 7/29-8/4 7/29-8/4 7/29-8/4 per Light Trap Date Date Date 8/5-8/11 21 YearMean 8/5-8/11 per Light Trap 8/5-8/11 21 YearMean 8/12-8/18 21 YearMean per Light Trap 8/12-8/188/12-8/18 8/19-8/25 - 8/19-8/258/19-8/25 pool” Species 8/26-9/1 8/26-9/18/26-9/1 9/2-9/8 9/2-9/89/2-9/8 9/9-9/15 9/9-9/159/9-9/15 9/16-9/22 9/16-9/22 9/16-9/22 Overwinter as 9/23-9/29 9/23-9/29 9/23-9/29 9/30-10/6 Eggs 9/30-10/6 10/7-10/139/30-10/6 10/7-10/13 10/14-10/2010/7-10/13 10/14-10/20 10/14-10/20 “Container” Species • Primarily Nuisance Mosquitoes • Desiccation-resistant eggs laid above waterline in containers • Larvae develop in an wide range of natural and artificial containers • Multiple generations per year • Strong Mammalian Association Arbovirus Isolates Oc. triseriatus = WN(5), EEE (4), JC (2), LAC (3) Oc. japonicus = WN(10) Ae. albopictus = WN(2) “Container” Species Ochlerotatus triseriatus Ochlerotatus japonicus Aedes albopictus Artificial Containers Natural Containers # Mosquitoes 0 1 1 2 2 3 3 4 4 5 5/27-6/2 6/3-6/9 6/10-6/16 6/17-6/23 “Container” Species “Container” 6/24-6/30 7/1-7/7 Ochlerotatus triseriatus Ochlerotatus 7/8-7/14 7/15-7/21 2018 7/22-7/28 7/29-8/4 Date 21 YearMean 8/5-8/11 per Light Trap 8/12-8/18 8/19-8/25 8/26-9/1 9/2-9/8 9/9-9/15 9/16-9/22 Overwinter as 9/23-9/29 Eggs 9/30-10/6 10/7-10/13 10/14-10/20 “Salt Marsh” Species • Nuisance Mosquitoes • Larvae develop in salt mash pools • Desiccation-resistant eggs laid in areas flooded by lunar tides • Multiple generations per year • Strong Mammalian Association Roger Wolfe, CT DEEP Arbovirus Isolates Oc.