Joumal of the American Mosquito Control Association, l4(2):lg6_195, l99gCopyright O 1998 by the American Mosquito Control Association, Inc.

FIELD EVALUATION OF COLORED LIGHT:EMITTING DIODES ASATTRACTANTS FOR WOODLAND MOSQUITOES AND OTHER

DIPTERA IN NORTH CENTRAL FLORIDA

DOUGLAS A. BURKETT, JERRY F BUTLER AND DANIEL L. KLINE

Department of Entomology and Nematology, [/niversity of Ftorida, Institute of Food and Agricultural Sciences, Buitd-ing 970, Hull Road, P. O. Box 110620, Gainesville, FL 326H-0620

ABSTRACT. The attraction of mosquitoes to transmitted light from colored super-bright light-emitting diodes(LEDs) (100-nm bandwidth) was evaluated by comparison of capture numbers with and without carbon dioxide-baited (200 mVmin) Centers for Disease Control (CDC) traps. Traps with either colored LEDs or control lightswere arranged in Latin square designs at 2 north central Florida woodland locations and checked daily duringJuly and August 1996. When data were analyzed by species, a significant difference in attractivity of lights wasfound in some species. Aedes atlanticus, Aedes dupreei, Aedes infrmatus, Anopheles cruciani s.l.,bulisetamelanura, Culex nigripalpus, Psorophora columbiae, and lJranotaenia sapphirina showed significant color pref-erences. These results will have potential for use by ecologists, epidemiologists, and mosquito control personnelfor improving collection efficiency of certain species of mosquitoes.

KEY WORDS Trap, color, vision, visual ecology, light traps, attractants

INTRODUCTION

Light-emitting diodes (LEDs) were evaluated asan alternative light source for use as an adult mos-quito attractant. Much of t}te research on dipterancolor preference is based on reflected light (Brett1938; Bracken et al. 1962; O'Gower 19631. Granger1970; Bradbury and Bennett 1974; Browne andBennett 1980, 1981; Allan and Stoffolano 1986).Many authors have shown that mosquitoes are at-tracted to transmitted light (Headlee 1937, Weiss1943, Williams et al. 1955, Bargren and Nibley1956, Breyev 1963, Wilton and Fay 1972, Gjullinet al. 1973, Browne and Bennett 1981). Few reportsdetail the response of individual species. Severalcolors (100 nm width) ofhighly efficient, low cost,super-bright LEDs have recently been developed.These colored LEDs when used in Centers for Dis-ease Control (CDC) traps have a greater intensityand require significantly lower amounts of energy(ca. 0.125 ma/h vs. 150 ma./h for standard CM-47bulb). We evaluated the use of LEDs as an inex-pensive light source and examined the relationshipbetween transmitted light color and its attractive-ness to woodland mosquito and other dipteran spe-cies.

MATERIALS AND METHODS

Three field trials were conducted using standardCDC-type traps (John W. Hock Co., model 512,Gainesville, FL) modified by replacing the standardbulbs with the LEDs. The LED was secured into apiece of 2 X 2-cm plexiglass and fastened to thescreen atop the lid assembly 3 cm below the alu-minum trap lid (Fig. 1). Trial 1 used 9-kg com-pressed-gas (carbon dioxide ICOr]) cylindersequipped with double-stage regulators (Victor

Equipment Co., model VTS453B-320, Denton, TX)and microregulators (Series M, Nupro, Wiloughby,OH) to maintain a constant gas flow of 200 mVmin.Carbon dioxide was delivered to the trap tbrough a3-m length of 8-mm Tygon@ (Norton PerformancePlastics Corp., Akron, OH) tubing secured with arubber band so the top of the tubing was even withthe top of the trap opening. Gas flow was checkedeach morning and evening using an in-line flow-meter (No. 12, Gilmont Instruments, Great NeckNY). Mosquitoes attracted near the trap intake weredrawn in by the trap fan and blown through ascreen funnel and into a l-quart polypropylene jarcontaining a 3 X 6-cm piece of dichlorvos-impreg-nated vinyl strip used as a killing agent. Powerson-ic@ (PowerSonic Corp., San Diego, CA) 6-V 10-amp-h rechargeable gel cell batteries were used torun the fan motor and standard incandescent light.

Six colors with and without CO, (trials I and 2):From July 15 to 20 (trial 1) and July 22 to 27 (trial2), 1996, different colored lights were used as at-tractants in standard CDC-type surveillance trapsusing a 6 X 6 Latin square design. Light, day, andposition effects were evaluated using a 3-way anal-ysis of variance (SAS Institute 1985) for the totalnumber and most cofiunon species represented inthe traps. Multiple comparisons were made usingthe Ryan-Einot-Gabriel-Welsh multiple range test(c : O.O5). Trial 1 used CO, as an additional at-tractant and trial 2 used the same randomization,but did not use COr. Four different colored super-bright Toshiba Tosbrighto (Martech Optoelectron-ics, Latham, NY) Ultrabright LEDs were comparedto no light and a standard GE@ (John W. Hock Co.,Gainesville, FL, CM-47, 6.3 V, 52O millicandela[mcd]) miniature lamp incandescent bulb used ascontrols. The diodes tested were red (613 + 50 nm.

1 8 6

JounNaL oF THE AMERTcIN Mosquno CoNrnol Assocrerrol Vor-. 14, No. 2

25

t

3 z oOa 1 5g)'6oo_cD to;9

Ae. dupreei Ae. atlanticus Ae. infimatus Cs. melanura

An. crucians Cx. nigripalpus Cx.(Melanoconion) Ps. ciliata Cq. perturbans W. sapphirina

Fig. 2. Relative percent composition of mosquito species captured in COr-baited Centers for Disease Control(CDC)-type traps using colored light-emitting diodes or incandescent light only. Means within each species grouphaving the same letter are not signi{icantly different (Ryan-Einot-Gabriel-Welsh multiple range test). c - 0.05, n =

6 nishts.

70

60

E s o6J! 40U'o'0

30(I)o_U)bs 20

1 0

ducted from August 12 to 21, 1996. Because of fluc-tuating water levels and mosquito populations at theAustin Cary Forest site, a similar, but more permanentcytr)ress swamp habitat was chosen north of Gaines-ville, FL. tn addition to the 4 LED colors and 2 con-trols previously discussed, 2 additional LED wave-

lengths, infrared (940 + 50 nm, 22' [Martech Opto-electronics, t atham, NY, model MTEl080l) and blue(450 + 5O nm, 800 mcd, 22" [Panasonic@, PanasonicTerhnologies, Inc., Princeton, NJI) were evaluatedalso. Using an 8 x 8 Latin square design, traps wereplaced around the perimeter of the swamp. Each trap

a a f _ - l a b

JuNr 1998 Coloneo Ltcgr-ElrtrrrNc DIotps As ATTRACTANTS

! 3 0o-

(6Oo 2 O0)'6oa" - 10

Ae. dupreei Ae. atlanticus Ae. infirmatus

An. crucians Cx. nigripalpus

was baited with 200 mymin CO, as in trial I andotherwise treated as before.

RESULTS

Six colors with and without CO, (trials I and 2)During the 6 trap-nights of trials I and 2, 32,059

and 1,916 specimens of mosquitoes were collected

Cs. melanura

Cx.(Melanoconion) Ur. sapphiina

from traps enhanced with CO, and those withoutCOr, respectively. The mosquito species composi-tions attracted to the incandescent light trap agreewith those found by Mann (1993). Responses of themost numerous mosquito species are shown in Fig.2a, 2b, and 3a, 3b. Means, standard errors, p val-ues, and signiflcant differences for species repre-sented in large enough numbers are shown in Ta-

70

60

9 5 0

8 + ou)Q)'6 30oo_

-; 20

1 0

Fig. 3t Relative percent composition of mosquitoes captured in Centers for Disease Control (CDC)-type traps usingcolored light-emitting diodes or incandescent light only. Means within each species group having the iame letter arinot significantly different (Ryan-Einot-Gabriel-Welsh multiple range test). ct : 0.05, n = O nlgttit.

Joumel op tHe AlasnrcAN Moseurro CoNrnoL AssocrATroN VoL. 14 , No.2

{

$

, ^ 9o q

^ e X

! r r . Eo q ;\ / v {

a - d ;

. 9 t r X8 . 5 :> E E

: : = 9i i i i "

C E E

Fr tmE'6 ,5

4

6l F-. $ F- - 6 , O. \n * F- 0O - ci !+ 0Oq n n n Q Q l - 9 l n l n o q r t q q l C

! r I e oq oq n q e n ci q q q \ .: q q Ni o \o o F- $ o 6l i o i o $ o o \o m o *

+t + t + t + t + t + t + t + l + t + t + l + t + t + t + t + t + t + t + lo F- r- O c-l € o O N r) 6 O r) d c.l oo F- O F-o d o o r; d ci F d d 6i cj.- c; -i ci ci o oiO\ \O O: 61 6 l h<' c.l r

e . i - € - o d 6 * j . . o o =8 n I e Q n q n : q -: c-'.r I o rc or o or f;Fr o n o o o ci ; i o -j o : d ^i e.i cj d :+ r + t + t + t + t + t + t + t + r + r + r + r + r + r + t + t + t + t + l0o u.) c..l o t-- oo o o c.r o t. c{ o o o f.- o ol t--r ; o J d + o c t d c . i o 6 i ^ ^ ; A i - j ^ a u :N n o

- f i - -€ N

- o <

c o € 6 d - - a - - € -

I J 3 n t i q e.i r c q "i ̂ j "r "t "e.j g: O $ O r ) r O i r O O O c n O O r ) C ) O i

| + l + t + t + t + t + l + t + t + t + t + t + t + t + t + t + t + t + lr) o F n ca cn o o o 6 0l o o e{ o ci n N F.-oi o d cj -j ri cj d + o i o.- d -j + J d -;O o \ - c ! o \r r r

€h d 6 . J - o 6 n 6 6 6 € d d - C Y

J ct.- q oc n q e - q n q n q n 9 n ct :O \ O ! O $ c . l O * - O * O \ O O O r ) O O i

+t + t + t + l + t + t + t + t + t + t + t + t + t + t + t + t + t + t + l\ n n.! q ol q \ oq q oq q oc e n \ q q qi o t- o t-- o\ o sf N o c.t o 00 0 * \o : o r)

c-.1 c\| * Ns c-l t--

E 6- :

c d + 6 ( ! ( ! 6 6 6 6 . 6 6 ( ! € :

3 q.l " i . j i q n oC.j oC q oC q -: \ 9 q €* O 6 O V ) N O * - O O O \ O i \ n N O i

+ t + t + l + t + t | + t + t + t + t + t + t + t + t + t + t + t + t + lF- N O al cO F. O t'- o 6l F- O O ol 6 f'. O r) Ooi d 6i o r; r; d od ri d -.' o 6 ci -i qi di d 6i

(.) 6 C.l n\o ct o\

: j . . , o d _ - 6 d 6 6 6 6 6 d Y

a - a - . a a $o Y * Y n ' : - i : Y Y ' . - : v : ' : Y - : : : O

- - ^ ^ r - - - f - - -

+t + t | | + t + t + t + l + t + t +1 + t + t + t + t + t + t + t + l\ q cl cl q cl q \ n q c! \ q q cl cl o! q c.!O\ O \O i O \O O r| i O : O\O O i O\ - O O$ O \ O a - l n 'n m o \

$isssiis$sissssS$$g

00

z

q

oI

q

og

r i

;. o

; l lt l

a t l

6 t lo t l

v t lI I

. i l

r! t l(/) ll+ t a l la E t lq b o l l3 ' E l l

t lA l l l lv - t lu : l l- ^ t l

' = 6 t lE ! 2 t l

\ - t l

E s.llN o l l

; , : t lb0 - t l

- a t l: o l l

8 + l la ) t l

€ e l l

t r v t l' : J t lv - l l

S i x l l

v > r t lb o d l ls v i l

' = 0 l l

q e l l.-! q ll

b o - l l5 > ' l l

9 r e l l

U F.IIl 0 a l l

- t lg a , l l

U E I Iq 6 l l6 i l lt s o l l. | = l lx ; , ; t l! t lr I o l l

_ - t l9 1 0 1 1t r > t lO c d l l(-,) E lls l l lS r l l

H A t lr o l l€ t l

t lL t lo t l

o t lo l lil' l l

t ls l l,o tl.a t lF t l

ob0

o

o

a

JuNs 1998 Coloneo Lrcnr-EutrrrNc DIoDES As ATTRAcTANTS 1 9 1

b0

t ls

o

oo0

o

o

I' r

r i

J

I(!

0

, o

(!

b0

92

oO

0

C)

o0

;

o

'

o

/\r r l

a

+ l

a

o0

o

o

o

b0

o

oo

!a

o0

l :

U

U

Uo

o

o

aQ

N

F

b0

z

o

oqqo

'=\o

o9

r l

oo0

o

o(t

o \ s- | O r O I o 6 r l I c \ O s fn I Q r - q I - 1 \ q . \ | | \ Q c l

6 6 6 ( ! € ( ! d 6 *

- . j q - q n t . j 0 q n n q q q \ c ,r o n o - * o o o o o o - d

+ t + t + t + t + t + t + r + t + l + t + t + t f t + lt - - o r ) o 6 \ N r ) € F - o o r F -6i ci F.- cj + + o d; o cj cj cj + d.n \o

\ o o N o N o o o N o o N o oM A _ A

+t + t + t + t + l + t + t + t + t + t + t | + t + lo l O € O 6 O O O N O O a I O F -

c o 6

o . 5 GN 6 6 . 0 6 € 6 d l u a

+ ? g c e - q q q c l c l c J n c ;6 r O 6 O O - O * O O O O O 6

+t + t + t f t f t + t + r + t + t + t + t + t + t + lot O € O F- o O V) ci N ol N 0O 6ld d o i o 6 i J d 6 i c i d c i c ; d r c js \ o

6 . o d - O c ! ( ! ( ! € - O ( !

ol O ol O O * O O\ t..l.i O O ci c.lR A ^ I A

+t + t + t + t + t + t + t | + t + t + t + t + t + l! . | o N o F - F - o o c . t F - o o F - €6 ci r- ci 6i cj o -.i d ci d c; d oiN o

€ - o ( !

a _ ( ! C i - o 6 € 6 € ! +

d ; q q q q ' 1 q n \ q q c - ' { n ;d o \ o o N o o i o o o o o c - l

+t + t | + t + t + t + t + t + t + t i l + t + t + l.O O o C.l oo F. O O F- al O C.l oo N-i d r; o + cj d 6i cj d d d ci od6 n

6 - 0 d

€ € € . o € d 6 o l o

c j . j q c l \ v? Q n . : c l q . ! .1 J

i t + t + t | + t + l + t + t + t + t + t + t + t + lh N o N F € C ) € o d O c l F - €+ - i - i A - . : i A A : ( A ^ ' - g O O t -c ) $

} I F F ;3 I _ j 8 * E g

t t i r= i iS$ i t FFtist€iii;€iiFiI r + + + i r E e c i r S E

E

n t ro e

l ' Io 0 - =\ / 9 b0

q 3 f i: o v

I r So ' E :

} .F Et 6.€-- --7s i u

c G 1 3' = = -i i :;!

. = . = vo . h <

bles 1 and 2. As noted in the tables, trap-positionand day effects were significant for some species.

No significant differences were observed for thetotal number of mosquitoes captured at different col-ors in either the COr-baited or unbaited trials (P :

0.08, P : O.24, respectively). However, differenceswere observed for individual species. In trial I, Ae-des dupreei (Coquillett), Aedes infirmaras (Dyar andKnab), An. crucians s.1., Culiseta melanura (Co-quillett), and Uranotaenia sapphirina (Osten Sack-en) showed significant color preferences. In trial 2,oriy Ae. atlanticus, An. crucians s.1., and Ur. sap-phirirn showed significant preferences. Aedes du-preei was the predominant species and was the onlyspecies preferring the COr-baited trap using no light.This species was also abundant in the no light con-trol. Three female Lutzomyia shannoni (Dyar) andone Lutzomyia vexator (Coquillett) were collectedduring trial l. None were collected in trial 2.

Eight colors with CO, (trial 3)

During the 8 trap-nights, 4,668 specimens ofmosquitoes, l, I 89 tabanids (Diac hlorus fernt gatusOsten Sacken), 3,667 chaoborids (Corethrellaspp.), and 3 phlebotomine sand fly specimens werecollected. Responses of the most numerous mos-quito species are shown in Figs. 4a, 4b. A highlysignificant difference was found in the total num-bers of mosquitoes captured for the different colors(P : 0.0001). Means, standard errors, P values, andsignificant differences for species represented inlarge enough numbers are shown in Thble 3. Asseen in trials I and 2, trap-position and day effectswere significant for some species. Overall captureof mosquitoes was significantly greatest with thestandard white broad-spectrum incandescent, fol-lowed by blue, green, orange, yellow, red, no lightcontrol, and infrared, respectively. When collec-tions were classified by mosquito species, clearpreferences were seen between species. Anophelescrucians s.1., Cs. melanura, Culex nigripalpusTheobald, Psorophora columbiae (Dyar and Knab),and Ur. sapphirina showed significant color pref-erences. White light captured the most An. crucianss.1.. The greatest numbers of Cs, melanura werecaptured in traps with white, green, and orange.The most Ps, columbiae were collected in trapswith blue, and significantly more (/r. sapphirinawere captured in traps with standard white or blue,No colors were found to be repellent to mosquitoeswhen compared to the no light controls. No signif-icant difference (P :0.26) for color attraction wereobtained for the tabanid D. ferrugatus. Conversely,the chaoborids (Corethrella spp.), showed signifi-cant color attraction (P : 0.002), preferring whiteand blue over the other colors.

DISCUSSION

Many common Florida woodland mosquitoes aremedically important. Although one of the primary

JOURNAL oF THE AMERTCAN Mosquno CoNrnol AssocrlrroN Vor-. 14, No. 2

! 2 5q)

( d 2 0()oo

8 1 5U);9 10

Ae. atlanticus Cs. melanura An. crucians Ur. sapphiina Cx. (Melanoconion)

Ps. columbiae Ps. fetox Cq. perturbans Ae. infirmatus Cx. nigripalpus

Fig. 4. Relative percent composition of mosquitoes captured in COr-baited Centers for Disease Control (CDC)-type traps using colored light-emitting diodes or incandescent light only. Means within each species group having thesame letter are not significantly different (Ryan-Einot-Gabriel-Welsh multiple range test). ct = 0.05, n : 8 nights.

E 2 5oL

x(d* 20c)u)o

8 1 5o-U)o \ 10

means of evaluating the presence or absence andrelative abundance of certain mosquitoes is throughthe use of light traps, few studies have evaluatedmosquito response to different wavelengths oftransmitted monochromatic light. Even fewer stud-

ies have detailed the response of individual specres.Browne and Bennett (1981) tested filtered light ofknown wavelengths to equate host preference withlanding rates for Coquillettidia perturbans (Walk-er). They found shorter wavelengths (40O-6OO nm

JurvB 1998 Colopeo LtcFf-EMrrrNc Droons As ATTRACTANTS 193

{

F

h Eo *

F r r - E- \ =\ / v {

a. .E 'E

* s 3a 5 :

b E E

= = aE E U

E C g

F.F"=, i ,5 4.

N O O O F€ o N a n € N o t € o d r I I l € r o oN O n € S O d O r h O O O | | | O t O O : : J : A

; ; : ; :

' " " r oq c t q q Q n n q ^ ! \ \ g € N o o $ _ , A . ^ri - o d ri ci Fi ^i o d s J r d ct o o ri : X+ l + l + r + l + i + r + t + + t + l + l + r + t + r + t + r + t + r + r + ln O , $ d O O O - 6 Q € - O n O O : ' A h €r ; , i o O + i r o o - j d r o o o o O G i v ;

- d o d r €d -

d o d d 6 d d € " o € - € " o j

n q c l n I : n - n q i t \ o - o o a r * - ^ri 6i o d ri d J o o o --: o + o o od,j -j =+t + l +t +t +t +t +t +t + l +t +t +t +t +t + l +t + l +1 +t +tq q n 9 0 c 9 t q q t q 9 1 - q q n q a qO \ o O O h c ) m N O N t o - c ) c ) o c ) o 6 t oN : - h

! q ! € . o€ o d n c s n ! d ! i i s s * o

a d j . - ! 1 1 a \ n q o q q ' : o - o - - € ; i$ e ct d r i i d r i o o^i - i ^ i d d d - i o :X

+t +r +t +t +t +t + l +t + l + l +t + l +t + l + l +t +t + l +t + l€ o 6 n € * n - O o n 6 r t n O : O r O 6 \ Or; 6 ct d.i o -i ^i o ^i qi r r d ct d -i + d +N F h o

PG o d d ( € G o d d G € G 6 3 6q.i a cl 'l cl \ q q n \ q \o o - o h i N iv t : . i o o d a - i o o o 6 i , j 6 i o o o d 6 i ' d :+ l + t + t + t + t + t + t + t + t + t + t + t + t + t + t + t + t + l + l + ln - € o n i h o \ o 6 o \ o i h - o 6 € o \ -..i + o o r ct r; r; o.j r; od -j o o o o vi r; oN n - N : N -

Px

G O d d 6 G 6 ! d a € d € 6 ! r

\ n n.'! - q 1 \ a n \ -: 09 q - q n oq -: -jN r o o \ t o - i o o N - N c o o o - < . -+ t + t + t + t + t + i + l + t + + t +1 + t + l + l + t + t + t + t + t + lh h € o € O O \ - - o \ O O O + - O n \ O 6 6v;.? o d oi o d d d - j d \o - j o o o o +. i oii s - N i N d

d a d d " " * 3 - € € . € . o i- q v? n q n oq q a I cl -: q a! q - 09 I - J* 6 O O n O i r O O + : 6 O O O O - € -

+ t + t + l + t + t + l + t + t + t + t + t + t + t + t + t + t + t + t + t + l- O € € o € O € - 6 - n @ $ O - O o n &od n o o r; d ri r o i ri d d d d d -i + ri +F s - N - N O

@

G o € d * c o E * E € * o " o EN N o N + O r r c ) * 6 - c ) N c ) O O O o n-j.+ cj o ri o o -i o o 6i j 6i d d cj o j -i o+ + r + r + t + t + t + r + t + t + t + t + t + t + t +1 + t + t + t + l + lO - € $ - € o - O n + @ n o O O O € * \ O€ - d o + o r;\d o i o. + J o o o o $ -; oi- N

. l : F a : tr - d - F * . S :

ssliIi$ii$sssssssui!

d o d d d d d € * o f - € - o ,n € + N - $ * + - € € N o N O O 6 6 o :+o o o r i o o o o d o o - i d d o o - i - i r ;+l + l + l + t + t + t + t + t + t + t + t + l + t + t + l + t + t + t + t + l9 9 C 1 " : - q q - : n 9 r n a q q n q p g6 N - O 9 * o o C # d N € O O O o * d $

, l l ,- i l do o l l >

! l l "r l li i l :E l l o

tr ll HI l l E= l l g; t la l lt r t ld t lo t lE i l :^ l l F; i l ;6 . l l zr r ^ l l" g t l

H FIII c l lE € I I

ilN I I I I

I . l l s. = ; t l

s . e l lE So l l

: d t l

l e l l. F . - - l l

l = l l c

= E l l I. 9= l l O

s{ l l9 . e l l

Efi I I' : J l t '

; f ; l t i6 i t le h t li l ( l l

€; i l' : o l l

q i # t l9 = i l o=*E l l I. 5 > i l E

E E I I 6E I l l

i E l l. a l ls a l lu 6 l l- c l l

E F l l rs E l l qa 6 l lF - t l! o l l

H s l lu t l= l l Ec l l q :

E l l 5o t l€ i la t l

o l lb l l* t l

r t lu ll u' l l Ed l l ': i lf l t l

t l

194 JounNeL op run AMr,nrcnN Mosquno Cotrnol AssocrlloN VoL. 14 , No.2

or blue-green) attracted significantly more mosqui-toes than did longer wavelengths. Their results cor-respond well to ours in trial 3. In Georgia, Bargrenand Nibley (1956) found Aedes yexans (Meigen),Culex salinarias (Coquillett), and Culex quinque-fasciatus (Say) to have varying levels of attractionto New Jersey traps using different colored bulbsof similar intensities. Other species, such as Cx. ni-gripalpus, showed no preference for any of the 4color bandwidths (447, 57O, 659, 670 nm) tested.This finding agrees with ours in trials 1 and 2, butdiffers from those of trial 3, which found significantcolor preferences (blue, green, white) for Cx. ni-gripalpus. Vavra et al. (1974) tested several typesand colors of light and found no significant differ-ences in the total numbers of mosquitoes attractedto each of the colors. Attraction of individual spe-cies of mosquitoes was not examined. In a labora-tory test using Culex tarsalis (Coquillett), Cx. quin-quefosciatus (Say), and Anopheles sierrenis (Lud-Iow), Gjullin et al. (1973) tested New Jersey lighttraps equipped with either ultraviolet light, or ce-ramic-dipped bulbs colored red, green, blue, or-ange, and white. They found no significant differ-ences in attraction between any of the colors tested.Wilton and Fay (L972) tested Anopheles stephensi(Liston) against a clear incandescent bulb and mon-ochromatic light of various wavelengths. Theyfound this mosquito highly attracted to bandwidthsof 29O and 365 nm in the ultraviolet region and690 nm, but blues, greens, and yellows (bandwidthsof 490, 540, and 590 nm, respectively) were not asattractive as the clear bulb.

Allan et al. (1987) stated that crepuscular andnocturnal biting flies are unlikely to have well-de-veloped color vision, but their abilities ro detect dif-ferences in intensity contrast are likely to be welldeveloped. Spectral sensitivity (i.e., relative sensi-tivity of the retina to light of different wavelengths)studies consistently showed that most flies possessa bimodal spectral response with peaks around 340and 525 nm (White 1985). Considering the varia-tion in mosquito species' attraction to light traps(Huffaker and Back 1943, Bidlingmayer 1967), itis not unreasonable to expect differences in colorpreference based on variations in their spectral sen-sitivities.

Alternatively, attractiveness may not be due tocolor per se. Different wavelengths may be physi-ologically perceived as more intense and subse-quently more attractive. Barr et al. (1963) conclud-ed that more intense light (up to a point) is moreattractive than less intense light. Electroretino-graphs (ERGs) conducted by Muir et al. (L992)showed Aedes aegypti (L.) to have spectral sensi-tivities ranging from ultraviolet (323 nm) to orange-red (621 nm) with sensitivity peaks in both the ul-traviolet (345 nm) and green (523 nm) wave-lengths. By studying the relationship between illu-mination and suitability of an oviposition site forAe. aegypti, Snow (1971) found a similar bimodal

response. Unfortunately, all mosquito spectral sen-sitivity studies have focused on Ae. aegypti; nonehave been conducted on nocturnal or other speciescommonly attracted to artificial light.

Unlike standard bulbs that radiate light in a 360"pattern, the diodes emit a narrow beam (8 or 22"),which in these tests was oriented upwards and re-flected off the shiny surface of the aluminum pancovering the CDC trap. If the mosquitoes are re-sponding to differences in perceived intensity, anassortment of several of the most promising LEDcolors (e.9., blues and greens) could be arranged toproduce a 360'pattern and perhaps greatly increasethe efficiency of the trap. Several LEDs in serieswould be many times brighter and still use signif-icantly less battery power than a single incandes-cent bulb. Several of the ERG studies previouslymentioned have shown peak dipteran spectral ac-tivity from bandwidths ranging from 450 to 550nm. Based on the numbers of certain mosquito spe-cies that were attracted to the blue and green wave-lengths, LED wavelengths between 450 and 550nm may produce excellent results. Currently, tech-nology limits production of LEDs producing thesewavelengths. Super-bright blues (450 nm) haveonly recently become available, and perhaps futuretechnology will produce a blue-green diode peakingat about 500 nm.

Light-emitting diodes run on significantly loweramounts of energy (ca. I ma/8 h) than incandescentbulbs, resulting in substantial savings in battery lifeand expense. Hours of use (means -f SEM) withthe no light control (69 + 7.5), blue (63 + 9), andgreen (63 -+ 5.7) were found to last significantlymore hours (n : 4, P : O.O2) than the standardwhite bulb (36 t 0). For convenient use, LEDs canbe soldered in series directly into the existing trapcircuitry. Best results for all colored LEDs exceptblue (100 O) were obtained using 200-.f) resistorsconnected to the light motor assembly. Future stud-ies should focus on combinations of colors orientedin different directions. The use of super-brightLEDs warrants serious consideration as a replace-ment for standard incandescent bulbs used in lighttraps. These results have potential for use in pop-ulation dynamics studies or for enhancing the at-tractivity for certain species.

ACKNOWLEDGMENTS

We thank John Reinert and Henry McKeithen,who helped with mosquito identifications and PeterPerkins, who identified the sand flies. We wouldalso like to acknowledge Diana Simon, Tim Rob-son, and Hayes Brown, who helped with field sam-pling. This article is published as Florida Agricul-tural Experiment Station Journal Series R-05768.

REFER.ENCES CITEDAllan, S. A. and J. G. Stoffolano. 1986. Effects of hue

and intensity on visual attraction of adult Tabanus ni-

JUNE 1998 Colonen LrcHT-EMrrrING DtoDEs ns ArrnecreNrs 195

grovittatus (Diptera: Tabanidae). J. Med. Entomol. 23:83-91.

Allan, S. A., J. F Day and J. D. Edman. 1987. Visualecology of biting flies. Annu. Rev. Entomol. 32:297-316.

Bargren, W. C. and C. Nibley. 1956. Comparative attrac-tiveness of colored lights of equal intensity to specificspecies of mosquitoes. Research report of the ThirdArmy Area Medical Laboratory, SU 3004. Ft. McPher-son, GA.

Barr, A. R., T A. Smith, lvi. Boreham and K. E. White.1963. Evaluation of some factors affecting the efficien-cy of light traps for collecting mosquitoes. J. Econ. En-tomol 56:123-127.

Bidlingmayer, W. L. 1967. A comparison of trappingmethods for adult mosquitoes: species response and en-vironmental influence. J. Med. Entomol. 4:2OO-22O.

Bracken, G. K., W. Hanec and A. J. Thorsteinson. 1962.The orientation of horseflies and deerflies (Tabanidae:Diptera). II. The role of some visual factors in the at-tractiveness of decoy silhouettes. Can. L Zoo1.40:685-695.

Bradbury, W. C- and G. E Bennett. 1974. Behavior ofadult Simuliidae (Diptera). I. Response to color andshape. Can. J. Zool. 52:251--259.

Brett, G. A. 1938. On the relative attractiveness to Aedesaegypti of certain coloured cloths. Trans. R. Soc. Trop.Med. Hyg. 32:113-124.

Breyev, K. A. 1963. The effect of various light sourceson the numbers and species of blood-sucking mosqui-toes (Diptera: Culicidae) collected in light traps. Ento-mol. Rev. 42:155-168.

Browne, S. M. and G. E Bennett. 1980. Color and shapeas mediators of host-seeking responses of simuliids andtabanids (Diptera) in the Tantramar marshes, NewBrunswick, Canada. J. Med. Entomol. 17:58-62.

Browne, S. M. and G. F Bennett. 1981. Responses ofmosquitoes (Diptera: Culicidae) to visual stimuli. J.Med. Entomol. 18:505-521.

Gjullin, C. M., D. G. Brandl and J. J. O'Grady. 1973.The effect of colored lights and other factors on thenumbers of Culex pipiens quinquifasciatus, Cx. tarsalis

and Aedes sierrensis entering light traps. Mosq. News33:67-7 1.

Granger, C. A. 1970. Trap design and color as factors rntrapping the salt marsh greenhead fly. J. Econ. Entomol.63:167O-1672.

Headlee, T. J. 1937. Some facts underlying the atffactionof mosquitoes to sources of radiant energy. J. Econ.Entomol. 3O:309-312.

Huffaker, C. B. and R. C. Back. 1943. A study of meth-ods of sampling mosquito populations. J. Econ. Ento-mol . 36:561-562.

Mann, M. O. 1993. Studies of the activity of adult Cz-liseta melanura (Coquillett) mosquitoes in Florida.Ph.D. thesis. University of Florida, Gainesville, FL.

Muir, L. E., M. J. Throne and B. H. Kay. 1992. Aedesae gypti (Diptera: Culicidae) vision: spectral sensitivityand other perceptual parameters of the female eye. J.Med. Entomol. 29 :27 8--281.

O'Gower, A. K. 1963. Environmental stimuli and the ovi-position behaviour of Aedes aegypti var. queenslandenisTheobald (Diptera: Culicidae). Anim. Behav. 11:189-197.

SAS Institute. 1985. SAS procedure guide, version 6 ed.SAS Institute, Cary, NC.

Snow, W. F. 197L. The spectral sensitivity of Aedes ae-gypti (L) at oviposition. Bull. Entomol. Res. 60:683-696.

Vavra, R. W., R. R. Carestia, R. L. Frommer and E. J.Gerberg. 1974. Field evaluation of alternative lightsources as mosquito attractants in the Panama CanalZone. Mosq. News 34:382-384.

Weiss, H. B. 1943. Color perception in insects. J. Econ.Entomol. 36:.l-17.

White, R. H. 1985. Insect visual pigments and colourvision, pp. 43I-494. In: C. A. Kerkut and L. I. Gilbert(eds.). Comprehensive insect physiology, biochemistryand pharmacology, Volume 6. Pergamon, Oxford, Unit-ed Kingdom.

Williams, C. B., R. A. French and M. M. Hosni. 1955.A second experiment on testing the relative efficiencyof insect traps. Bull. Entomol. Res. 46:193-204.

Wilton, D. P. and R. W. Fay. 1972. Responses of adultAnopheles stephensi to light of various wavelengths. J.Med. Entomol. 9:301-304.