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

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 Culiseta melanura

Culiseta melanura per Light Trap 2018 21 Year Mean

35 3 Generations 30

20 Culiseta melanura Overwinter as 15 Larvae # Mosquitoes

• 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 Culex salinarius

Culex salinarius per Light Trap

2018 21 Year Mean

25 Overwinters as Mated Female 20 # Mosquitoes #

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

Date 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 Coquillettidia perturbans

Coquillettidia perturbans per Light Trap

2018 21 Year Mean 350

300

250

200

Overwinter as 150 # Mosquitoes # Larvae

100

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 10/14-10/20 Date “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 “Floodwater” Species

Aedes vexans per Light Trap

2018 21 Year Mean

70 Overwinter as 60 Eggs

30 # Mosquitoes #

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

Date 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 “Vernal Pool” and “Snow-pool” Species

OchlerotatusOchlerotatusAedes cinereus stimulans abserratusperper Light Lightper Trap Light Trap Trap Overwinter as 201820182018 21 Year2121 YearMean Year Mean Mean Eggs 405 40

4 3 Generations 35 35

4 30 30

3 25 25

3 20 20 2 # Mosquitoes # 15 # Mosquitoes # 15

# Mosquitoes # 2

10 1 10

5 1 5

0 0 6/3-6/9 7/1-7/7 9/2-9/8 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 5/27-6/2 7/8-7/14 7/29-8/4 8/5-8/11 8/26-9/1 9/9-9/15 6/3-6/9 7/1-7/7 9/2-9/8 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 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 5/27-6/2 7/8-7/14 7/29-8/4 8/5-8/11 8/26-9/1 9/9-9/15 10/7-10/13 10/7-10/13 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 10/14-10/20 10/14-10/20 Date 10/7-10/13 DateDate 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 “Container” Species

Ochlerotatus triseriatus per Light Trap

2018 21 Year Mean 5 Overwinter as 4 Eggs

2 # Mosquitoes # 2

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

Date 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. sollicitans = WN (1), EEE (3), JC (6), Oc. cantator = EEE (5), JC (72) Oc. taeniorhynchus = WN (6), JC (17) “Salt Marsh” Species

BEFORE AFTER

Roger Wolfe CT DEEP Roger Wolfe CT DEEP “Salt Marsh” Species

Ochlerotatus taeniorhynchus per Light Trap

2018 21 Year Mean

60 Overwinter as Eggs 50

30 # Mosquitoes # 20

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

Date 10/7-10/13 10/14-10/20 Questions?