Visual Attraction of Ovitraps for Surveying Visual Attraction of Ovitraps for Surveying Field Populations of Field Populations of AedesAedes Mosquitoes Mosquitoes

LCDR P. J. Obenauer, MSC, USNLCDR P. J. Obenauer, MSC, USN

• SurveillanceSurveillance

• Efficient and EconomicalEfficient and Economical

• ControlControl

• Safe / non-toxicSafe / non-toxic• Insecticidal ovitrap Insecticidal ovitrap (Perich et al. 2003)(Perich et al. 2003)

• Sticky ovitrap Sticky ovitrap (Facchinelli et al. 2007, Zhang and Lei 2008)(Facchinelli et al. 2007, Zhang and Lei 2008)

• Biodegradable lethal ovitrapBiodegradable lethal ovitrap(Richie et al. 2008)(Richie et al. 2008)

AedesAedes Ovitrap Applications Ovitrap Applications

Host-Seeking Cues for Host-Seeking Cues for AedesAedes Mosquitoes Mosquitoes (Brown, A. W. A. 1956)(Brown, A. W. A. 1956)

• MoistureMoisture• Carbon DioxideCarbon Dioxide• Convective heatConvective heat• MovementMovement• ContourContour

• Black and white interfaces = increased attraction by 60%Black and white interfaces = increased attraction by 60%

• ReflectivityReflectivity• Decreases attractivenessDecreases attractiveness• Black surfaces attracted 5X as many Black surfaces attracted 5X as many Ae. aegyptiAe. aegypti

compared to whitecompared to white

Use of Visual Cues to Attract Use of Visual Cues to Attract Host-Seeking MosquitoesHost-Seeking Mosquitoes

Factors Influencing Factors Influencing Aedes aegyptiAedes aegypti Oviposition Oviposition (Fay and Perry 1965)(Fay and Perry 1965)

• Water Absorptive PropertiesWater Absorptive Properties

• RoughnessRoughness

• Color of Test MaterialsColor of Test Materials

Aedes aegyptiAedes aegypti (Fay and Perry 1965)(Fay and Perry 1965)

TONGUE TONGUE DEPRESSERDEPRESSER

% EGGS% EGGS

White BlotterWhite Blotter 1313

Brown BlotterBrown Blotter 8080

UncoveredUncovered 22

Brown Bag Brown Bag PaperPaper

55

Factors Influencing Factors Influencing Aedes Aedes triseriatustriseriatus Oviposition Oviposition (Wilton 1968)(Wilton 1968)

• Orientation of container openingOrientation of container opening

• Texture of wallTexture of wall

• Optical densityOptical density

• Color of container wallColor of container wall

• Presence of decaying organic matterPresence of decaying organic matter

• Color of container backgroundColor of container background

Factors Influencing Oviposition inFactors Influencing Oviposition in Aedes triseriatusAedes triseriatus (Beehler et al. 1992)(Beehler et al. 1992)

FACTORFACTOR %%

DYED WATERDYED WATER 8989

DECAYING OAK LEAVESDECAYING OAK LEAVES 3131

DARKENED CONTAINERDARKENED CONTAINER 4747

EGGS ON SUBSTRATEEGGS ON SUBSTRATE 6969

PRESENCE OF LARVAEPRESENCE OF LARVAE 4141

* Factors in a Fractional Factorial Design Combination

Aedes triseriatusAedes triseriatus (Williams 1962)(Williams 1962)

COLORCOLOR TOTAL # of EGGSTOTAL # of EGGS

REDRED 4,6064,606

BROWNBROWN 4,5784,578

YELLOWYELLOW 366366

GREENGREEN 4,1744,174

PURPLEPURPLE 4,5994,599

BLUEBLUE 4,6724,672

Aedes triseriatusAedes triseriatus (Williams 1962)(Williams 1962)

COLORCOLOR TOTAL # of EGGSTOTAL # of EGGS

REDRED 4,6064,606

BROWNBROWN 4,5784,578

YELLOWYELLOW 366366

GREENGREEN 4,1744,174

PURPLEPURPLE 4,5994,599

BLUEBLUE 4,6724,672

Effect of Color on Selection of Effect of Color on Selection of AedesAedes Oviposition Sites Oviposition Sites (Gubler 1971)(Gubler 1971)

ColorColor BackgroundBackground Water ColorWater Coloralbopictusalbopictus polynesiensispolynesiensis albopictusalbopictus polynesiensispolynesiensis

BlackBlack 72.872.8 66.566.5 70.770.7 79.579.5

BrownBrown 19.719.7 20.720.7 10.810.8 8.78.7

RedRed 11.111.1 7.87.8

YellowYellow 1.31.3 0.60.6

OrangeOrange 1.11.1 0.120.12

GreenGreen 2.22.2

BlueBlue 0.80.8 1.11.1

WhiteWhite 7.57.5 12.812.8 -------- --------

Effect of Color on the Selection of Effect of Color on the Selection of AedesAedes Oviposition Sites Oviposition Sites (Gubler 1971)(Gubler 1971)

• Ae. polynesiensisAe. polynesiensis was more influenced by chemical was more influenced by chemical factors in the water compared to visual factorsfactors in the water compared to visual factors

• Ae. albopictusAe. albopictus more influenced by visual stimuli than more influenced by visual stimuli than contact chemoreceptioncontact chemoreception

• No specific color distinction, rather light & darkNo specific color distinction, rather light & dark

• Colors of a shorter wave length were not attractiveColors of a shorter wave length were not attractive

Aedes albopictus Aedes albopictus Visual Attraction Visual Attraction (Yap et al. 1995)(Yap et al. 1995)

Glass jarsGlass jars % of total collected% of total collected(mean (mean ± SE)± SE)

Glossy whiteGlossy white 4.8 4.8 ± 2.0 cd± 2.0 cdYellowYellow 11.5 11.5 ± 3.1 bcd± 3.1 bcd

GreenGreen 16.0 16.0 ± 2.4 bc± 2.4 bc

RedRed 22.2 22.2 ± 2.1 ab± 2.1 ab

BlueBlue 20.4 20.4 ± 7.0 ab± 7.0 ab

BlackBlack 24.4 24.4 ± 6.1 a± 6.1 aClear (Control)Clear (Control) 0.8 ± 0.2 d 0.8 ± 0.2 d

Aedes albopictus Aedes albopictus Visual Attraction Visual Attraction (Yap et al. 1995)(Yap et al. 1995)

Glass jarsGlass jars % of total collected% of total collected(mean (mean ± SE)± SE)

Glossy whiteGlossy white 4.8 4.8 ± 2.0 cd± 2.0 cdYellowYellow 11.5 11.5 ± 3.1 bcd± 3.1 bcd

GreenGreen 16.0 16.0 ± 2.4 bc± 2.4 bc

RedRed 22.2 22.2 ± 2.1 ab± 2.1 ab

BlueBlue 20.4 20.4 ± 7.0 ab± 7.0 ab

BlackBlack 24.4 24.4 ± 6.1 a± 6.1 aClear (Control)Clear (Control) 0.8 ± 0.2 d 0.8 ± 0.2 d

Response of Host-Seeking Female Response of Host-Seeking Female Ae. aegyptiAe. aegypti (Sippell and Brown 1953)(Sippell and Brown 1953)

• Increasing contrast = increased Increasing contrast = increased attractionattraction

• Black and white interface through a Black and white interface through a checkerboard patterncheckerboard pattern

• Glossy black was more attractive than Glossy black was more attractive than flat blackflat black

What about Oviposition?What about Oviposition?

Site SelectionSite Selection

• Residential / Suburban areas Residential / Suburban areas

• Large numbers of Large numbers of Aedes albopictusAedes albopictus

• Shaded areasShaded areas

• Thick vegetationThick vegetation

Materials & MethodsMaterials & Methods

• Ovitraps = 11 X 9 cm black plastic cupsOvitraps = 11 X 9 cm black plastic cups

• Substrate = #76 Seed germination paperSubstrate = #76 Seed germination paper

• 200 ml of 6 d-old 200 ml of 6 d-old Ae. albopictusAe. albopictus larval water larval water

• Ovitraps secured w/ stakesOvitraps secured w/ stakes

• Ovitraps cleaned weekly / new water addedOvitraps cleaned weekly / new water added

• CheckeredCheckered• StripeStripe• OrangeOrange• BlueBlue• WhiteWhite• BlackBlack

GO GATORS!!

North Florida Field SitesNorth Florida Field Sites

• Conducted from July to September 2009Conducted from July to September 2009

• 6 consecutive weeks (trials)6 consecutive weeks (trials)

• 54 ovitraps54 ovitraps

• 6 treatments / site6 treatments / site

• 3 sites / location (Gainesville, Jacksonville, NAS)3 sites / location (Gainesville, Jacksonville, NAS)

• Traps set between 0800 and 1100Traps set between 0800 and 1100

• Operated for 1 week = 1 trap periodOperated for 1 week = 1 trap period

Experimental DesignExperimental Design

Statistical AnalysisStatistical Analysis• Randomized block design Randomized block design

• Response = # of eggs / ovitrap / weekResponse = # of eggs / ovitrap / week

• Data transformed with logData transformed with log1010 (n+1) prior to analysis (n+1) prior to analysis

• PROC GLM, Analysis of Variance (ANOVA)PROC GLM, Analysis of Variance (ANOVA)

• Multiple mean comparisons of mosquito egg Multiple mean comparisons of mosquito egg recovered using Ryan-Einot-Gabriel-Walsh recovered using Ryan-Einot-Gabriel-Walsh (REGW) Multiple Range Test ( (REGW) Multiple Range Test ( αα = 0.05) = 0.05)

Mea

n #

of E

ggs

/ Ovi

trap

Mea

n #

of E

ggs

/ Ovi

trap

0

40

80

120

ResultsResults

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* Treatments marked with the same letter are not significantly different α = 0.05, (REGW). N = 54 (F = 4.18, df = 5, 249, P = 0.0012)

ConclusionsConclusions

• Significant differences (Significant differences (α = 0.05) detected among detected among sites and trialsites and trial

• 4 Species: 4 Species: Aedes albopictus, Ae. triseriatus, Aedes albopictus, Ae. triseriatus, Orthopodomyia signifera, Toxorhynchites Orthopodomyia signifera, Toxorhynchites

• 90% positive for 90% positive for Ae. albopictusAe. albopictus

• Black colored ovitraps were more attractive Black colored ovitraps were more attractive compared to stripe or whitecompared to stripe or white

AcknowledgementsAcknowledgements

• CDR D. F. HoelCDR D. F. Hoel

• Jacksonville Mosquito Control District (Marah Clark)Jacksonville Mosquito Control District (Marah Clark)

• Navy Entomology Center of ExcellenceNavy Entomology Center of Excellence

• Dr. Matt AubuchonDr. Matt Aubuchon

• Dr. Sandra AllanDr. Sandra Allan

• Dr. Gerry HogsetteDr. Gerry Hogsette

• Dr. Don HallDr. Don Hall

• Dr. Faith & David OiDr. Faith & David Oi