SOCIETY FOR VECTOR ECOLOGY

BSOVE

13(

2):

221- 360 ( 1988)

ISSN 0146- 6429

Bulletin of the

SOCIETY FOR

VECTOR ECOLOGY

BULLETIN OF THE

SOCIETY FOR VECTOR ECOLOGY

Volume 13- Number 2 December 1988

James P. Webb, Editor

Orange County Vector Control District

13001 Garden Grove Boulevard

Garden Grove, CA 92643

EDITORIAL BOARD

Mir S. Mulla, Chairman,

University of California

Riverside, CA 92521

A.J.Adames _J.B.Davies R. S.Lane F. J. Radovsky

University of Panama Liverpool Sch. of_TropMedicine UniversityofCalifornia NC State Museum Nat. Hist.

Panama Liverpool, England Berkeley,California Raleigh, North Carolina

A.All M. S. Dhillon L. A. Magnarelli R. E. Ryckman

University of Florida _{Northwest M.A.D.} Conn. Agr. _Exp. Station _{Loma Linda University} Sanford, Florida Riverside, California New Haven, Connecticut Loma Linda, California

D.R. Barnard P.Eisen C.J.Mitchell H. I. Scudder

Lone Star Tick Research Lab. Institute of _Trop. Medicine Centers for Disease Control _{California State University}

Poteau, Oklahoma _{Antwerp, Belgium} Fort Collins, Colorado Hayward, California

N. Becker R. E.Fontaine G. R.Mullen M. W. Service

University of _{Heidelberg CDC, Public Health Service} Auburn _{University Liverpool Sch. of Trop. Mcd.} Heidelberg, West _Germany Atlanta, Georgia Auburn, Alabama Liverpool, England

H. Briegel _{M. L. GoIT} S. Salim E. S. Tikasingh

University of Zurich _University of Hawaii, Manoa VectorControlResearch Unit _{Caribbean Epidemiology Ctr.} Zurich, Switzerland _{Honolulu, Hawaii} Jakarta, Indonesia Port of Spain, Trinidad

G. G.Clark D.J.Gubler G. F.O' Meara G. B. White

CDC, PublicHealth Service _{CDC, Public Health Service University} of Florida, WAS _{London Sch. Hyg. Trop. Mcd.} San Juan, Puerto Rico _San Juan, Puerto Rico Vero Beach, Florida London, England

W.J.Crans C. FHopla S.Palchick S. C. Williams

Rutgers _University

University of Oklahoma Metro. _Mosq. Cont. Dist. San Francisco State Univ.

New Brunswick, New _Jersey Norman, Oklahoma St. Paul, Minnesota San Francisco, California

C.Dahl M.J.Klowden M. A. Parsons W. J. Wrenn

Uppsala _University

University of Idaho Department of Health _{University of North Dakota}

Uppsala,Sweden Moscow, Idaho Columbus, Ohio Grand Forks, North Dakota

L. A._Lacey D. B. Pence

Medical Services Consultants Texas Tech University

Arlington, Virginia Lubbock, Texas

Published by the Society for Vector Ecology to disseminate pertinent information from all facets of the field of Vector Ecology and Related Disciplines

Membership

Plus Bulletin $ 25. 00

Student

_{Membership $}

12. 50 Institutional Subscription $ 25.00

Sustaining

Members $ 150. 00

Communications relating to editorial matters and manuscripts should be addressed to the Editor. Communications relating to Balky proofs,

reprints, subscriptions, SOVE membership, change of address, and other matters

should be addressed tothe Business Omen. PUBLICATIONS AND BUSINESS OFFICE

Society for Vector Ecology P. O. Box 87

Santa Ana, California 92702 USA

PrintingConsultant Minoo B. Madon, Production Manager

John G. Shanafelt, Jr. Environmental Management Branch

Orange, California California State Department of Health Services

BULLETIN

OF THE

SOCIETY FOR VECTOR ECOLOGY

Volume 13 December, 1988 Number 2

CONTENTS

Submitted Papers

The Aquatic Insect Communities of Tree Holes in Northern California Oak Woodlands

D.L.Woodward, A. E. Colwell, andN.L. Anderson 221

Population Trends and Behavioral Attributes of Adult Mosquitoes Associated with Dairies in Southern

California E. T. Schreiber,M.S. Mulla,andJ. D.

_Chaney

235

Factors Affecting Oviposition and Egg Production in Laboratory- Reared Anopheles pharoensis

Theobald A.S. El- AkadandJ. G.Humphreys 243

The Effect of Habitat Management and Toxic Bait Placement on the Movement and Home Range

Activities of Telemetered Rattus rattus in Orange County, California

M. A. Recht, R.Geck,G.L.Challet,andJ. P. Webb 248

Proceedings

2nd European SOVE Branch Meeting, Heidelberg, WEST GERMANY

31 August-2 September 1987

Black Fly ( Diptera: Simuliidae) Control in West Germany with the Biological Larvicide Bacillus

thuringiensisvar.israelensis W. E. Deschle, H.-E. Hagen, J. Rutschke,M. Starner,andT. Meyer 280

19th Annual SOVE Conference, Asilomar Conference Center, Pacific Grove, California

18-20 November 1987

Current Trends in Researchand

_Training

inVector- Borne Diseaseon aGlobal Basis T. Godal 287

Urban Vectorand Pest Control in

_Developing

Countries R.J. Tonn 291

ControlPotentials in

_Feeding

Mechanismsof_{Mosquito Larvae C. Dahl 295}

Aedesaegypti:

_Why

Can'tWe Control It? S. B. Halstead 304

CantheWartoContainVectors be Lost? B. H.

_Kay

312

Marking Adult Mosquitoes Using Fluorescent Pigments in Dispersal Studies

C. L. Meek, J. C. Fryer,andM. L.Niebylski 319

Medical

_Entomology

Manpower: AnAnalysisandaPlan H. I.Scudder 323

Observations on Anopheline and Malaria Ecology in the Far Western Region of Nepal, 1986

S. L. Shrestha, S. Pradhan, J. P. B. Shrestha,

J. D. Shrestha, Y. Rajbhamdari, G. L. Shrestha, T. B. Swar, M. K.Nushin, and W. K. Reisen 332

Performance of Pyrethroids Against German Cockroaches Blattella germanica (L.) (Dictyoptera:

Blattellidae) M. K.RustandD. A.Reierson 343

Bluetongue in the United States: _{Status, Transmission, and Control Through Vector Suppression}

F. R. Holbrook 350

VectorControlonU. S.

_Army

Installations R. N.Johnson 354

BULL. SOC. VECTOR ECOL., 13( 2): 221- 234

DECEMBER, 1988

THE AQUATIC INSECT COMMUNITIES OF TREE HOLES IN

NORTHERN CALIFORNIA OAK WOODLANDS

D. L. Woodward', A. E. Colwell', and N. L. Anderson'

ABSTRACT: A survey of the aquatic insect fauna of water-filled tree holes in northern California identified two

species of ceratopogonids, two chironomids, two culicids, one syrphid, one psychodid, and one helodid. The most

common insects encountered were immatures of the western treehole mosquito, Aedes sierrensis. Tree hole surface

area and leaf litter weight were correlated with the number of insect species per tree hole. The emergence periods,

habitat characteristics, and possible food of some of these organisms are described.

INTRODUCTION

_{have been described ( Jenkins and Carpenter 1946,}

Garcia and Ponting 1972, Hawley 1985) and a number

Tree holes filled with rainwater and _containing

_{of investigators have studied its pathogens and parasites}

fallen leavesand stems_{usually form habitats}

supporting (

Sanders 1972, Clark and Brandl 1976, Samson and

detritus- based invertebrate communities.

_Many

of

Soares 1984, Egerter and Anderson 1985, Washburn et

theseinvertebratesarefoundinno otherhabitator are al. 1988).

_{This is the first study concerned with}

largely

restricted to water-filled tree holes (

_Kitching

examining the other dendrolimnetobiont community

1971). Rohnert ( 1950) used the term " dendro-

_{members from tree holes in oak woodlands of northern}

limnetobiont" todescribesuchspecies. Becausesome

California. The biology and taxonomy of the insects

oftheseinvertebratesare_rarelycollectedorstudied,the _{associated with most other culicid vectors of disease are}

systematics, _especially of the immatures, are often

_{well known when compared to those associated withAe.}

poorly known. As a result, studies of tree-hole

sierrensis. A more thorough understanding of the entire

communities _{have rarely includeda complete species}

tree-hole community may be beneficial in control

list( Fish1983). _{The only known North American study efforts against this mosquito.}

with a complete list was provided by Snow( 1958) in his

analysis of the spatial distribution of the insect

_{MATERIALS AND METHODS}

community in a water-filled stump in Illinois. Rohnert

1950)and

_Kitching(

1971) providedEuropeanspecies

_{Northern oak woodlands ( Munz 1965) of Lake}

lists from water-filled tree holes in

_Germany

and

County and eastern Mendocino County ( Longitude

England, respectively.

Kitching

andCallaghan(1981)

_{122° 38 IV to 123° 06' W, latitude 38° 42' N to 39° 14' N)}

reported a specieslist forwater-filledtreeholes ina rain

_{were searched for water-filled tree holes. Most large}

forestofsouthernAustralia.

_Kitching(

1983)compared

native trees in these areas are Quercus lobata Nee

the _communitystructure of water-filled tree holes in (

valley oak), Quercus kelloggii Newberry ( California

EuropeandAustralia.

_{black oak), Quercus wislizenii Candolle ( interior live}

Water- filled tree holes in oak woodlands of the

_{oak), and Arbutus menziesii Pursh( Pacific madrone).}

northernCalifornia Coast Range have beenstudied

_by

Elevation in the study area ranges from ca. 365 to 425 m

anumber of workers sincelarvaeofthemosquitoAedes

above sea level. Rainfall averages 71 cm annually in the

sierrenis(Ludlow)arethemost commoninsectsinthat

city of Lakeport, near the center of the study area.

habitat. Femalesofthisspecies are serious

_biting

pests

_{Summers are hot and dry. Winters are wet and mild with}

of man anddomesticatedanimalsin_manyareas ofthe

_{most rain falling in November to March of each year.}

Pacific Northwest( Bohartand Washino1978,Papineau

_{Based on a yearly cycle of July 1 to June 30, the}

1983-1984)andhave been implicatedasimportantvectorsof

_{84 and 1984- 85 seasons produced 93. 7 and 53. 2 cm of}

Dirofilaria immitis(

_Leidy),

thenematode responsible

_{rainfall, respectively( Fig. 1).}

for

_dog

heartworm disease ( Weinmann and Garcia

_Two

_{types of water-filled}

_{tree holes were}

1974). The life

_history

and

_biology

ofthis mosquito

_{identified. The most common occurred with regrowth}

222 BULL.SOC. VECTOR ECOL. DECEMBER, 1988 40 35 MIN. TEMP. MAX. TEMP. 35— 30••: •, i. RAINFALL , S 30 —

II

t % % I

i-

25 —

II

20 V

FW--

20 — t / la..

P

Z• 15

S

Z _j 0 10 I e

5-1

p

1

i /.

o ;. !

0

0 .

rp o J A S O N D J F M A M J J A S O N D J F M A M J

1983

1984

1985

Figure 1.

Mean monthly high and low temperatures and monthly precipitation near Lakeport, Lake County,

California from July 1, 1983 to June 30, 1985. ( Precipitation data were provided by the Lake County

Air Quality Management District, Lakeport, CA. Temperature data were supplied by Albert Reuss,

DECEMBER, 1988 BULL. SOC. VECTOR ECOL. 223

of multiple stems

_following

_cutting or death of the

_{were teased apart in a droplet of deionized water on a}

original_primarystem. Afteryears of regrowth,apan, _{microscope slide. The slide was viewed at 40- 1000X}

often capableof

_holding

rainwater,occursinthecenter

under a compound microscope for identification of the

ofa_ringof_secondarytree trunks.Panswere_foundfrom gut contents.

ca.0. 2mbelowto1. 0mabove groundlevel. Tree holes

_{The predatory capacity of Culicoides spp. larvae}

ofthisformwere reportedtobethemostcommontype

for Ae. sierrensis larvae was tested in the laboratory. A

inan oaksavannahin Wisconsin

_by

HansonandHanson

_{previous study ( Clark and Fukuda 1967) reported}

1970). Rot holes formafterabranch breaksoff of a

_{predation by larvae of Culicoides cavaticus Wirth and}

tree. _{The remaining} portion and the _adjoining trunk

_{Jones upon fourth instar Ae. sierrensis. A total of 10}

may become hollow and hold rainwater. Rot holes

_{replicates was done to analyze the extent of this}

sampled were ca. 1.5to6. 0mabove ground.

_Kitching

_{phenomenon. Seven replicates tested fourth instar Ae.}

1971) defined "pans" and " rot holes" in a similar

sierrensis. Three replicates were completed using first

manner.

through third instar Ae. sierrensis in approximately

Pans in 32

_Q.

kelloggii, 4

_Q.

wislizenii, 3 A.

_{equal numbers in each replicate. Ten ml of filtered}

tree-menziesii,and5rotholesin

_Q.

lobataweresurveyedfor

_{hole water( 801.1. filtration) was added to each of 20, 50}

immature insects from 1983through 1985. Thesetree

_{ml glass beakers. Ten Ae. sierrensis larvae( instars as}

holes arelocatedat eight sites between Lower Lake, described above) were added to each beaker. Ten Lake

_County,

and Lake Mendocino in Mendocino

_{fourth-stage larvae of Culicoides spp.( collected from 5}

County.

The treeholes are separated

_by

a maximum _{tree holes) were added to each of 10 of the beakers. The}

distanceof56km. other 10 beakers served as controls. Each beaker

Qualitative sampling for insectswas accomplished

_{containing both genera was observed at irregular}

by

stirringthecontentsofthe treeholeand_removinga

_{intervals for visual evidence of predation. The number}

150mlsampleof wateranddetrituswitha polyethylene _{of Ae. sierrensis larvae alive in each beaker was} pipette.Themouth ofthepipettewas5mmin diameter, determined after 40 hours.

largeenoughto collect maturelarvaeofeachdendro- _{In the last week of March, 1985, a water sample}

limnetobiont insectspecies. Insectswereidentifiedand _{was collected from 12 of the 39 pans surveyed for} countedinenamelpansinthefieldand returnedto the

_{immature insects. These included five Q. kelloggii,}

treehole. Thisprocedurewasrepeatedthree timesfor

_{four Q. wislizenii, and three A. menziesii tree holes. A}

eachtreeholeper_{sampling date. Each}treeholewas

_{similar sample was collected from three Q. lobata pans}

surveyedfrom3 to24timesbetweenNovember 7and in the _study area.

_{The pH and conductivity were}

May

3of1983- 84and1984-85. Fifteenofthe treeholes

_{measured by electrode in the laboratory. All leaf litter}

weresampled on21 dates in 1983- 84toinsurethatno _{was removed from each pan, drained, weighed, and} species was missedbecauseofimproper_timingofthe _{returned to the tree hole. Emergence traps were then}

surveys. Theothertreeholesweresampled on3to 10 _{placed over each of the 15 pans. Emergence traps were}

dates each. Mean length andwidth of eachtreehole

_{constructed of surgical stocking painted black on the}

were determined

_by

_averaging a series of measure- _{outside. One end was stapled and taped over the} tree-ments. Theproduct of meanlengthand meanwidthwas

_{hole opening. The other end was attached to an}

used toestimate surface areaofeachtreehole. Max-

_{inverted funnel. A 250 ml clear plastic cup was placed}

imumdepthof eachtree holewhenfull ofwaterwas

_{over the small opening of the funnel so adult insects}

recorded.

_{could enter the container. Each trap was maintained in}

Except forthechironomidLimnophyes hamiltoni

_{a taut, upright position by wires connected to branches}

Saether, larvae of all species presumed to be _{and trunks of the tree. Adult insects which did not} dendrolimnetobionts were reared to adults in the

_{fly into the cup were aspirated out of the surgical}

laboratory.

Larvae ofL. hamiltoni are difficult to

_{stocking through a zippered opening. Emerging adults}

maintain in the

_laboratory,

but field-collected pupae _{were collected from each tree hole once per week}

were reared to adults. Culicids were identified

_beginning

March 25, 1985. Collections were according to Bohart and Washino ( 1978). Adultsof

_{terminated when the tree holes dried completely and}

other species were identified

_by

several taxonomists adult emergence stopped. Some larger or deeper tree

seeAcknowledgements). holes were monitored until September 2, 1985. After Gut-content analyseswereperformedon all ofthe emergence data were collected for the season, the non- culicidtree-hole insects.

_Freshly

field-collected

_{volume of each tree hole was determined by emptying}

larvae were washed and the digestive tracts were

_{the hole and filling it to capacity with a measured}

224 BULL.SOC. VECTOR ECOL. DECEMBER, 1988

RESULTS in tree holes in the eastern United States, uses a cibarial filter to feed upon fine-grained tree hole detritus. The

The 39pans surveyedhadameansurface area of digestive tracts of 12 B. humeralis larvae examined 335. 7cm2(

range36-1064cm2).

The meanmaximum

_{during this study contained primarily ciliate protozoans}

depthmeasured 10.9cm( range4- 29cm). The five

Q.

and fine-particle detritus.

lobatarotholes hadameansurface area of1499cm2

One B. humeralis pupa was collected in moist leaf

range 25- 4800 cm2)

and amean maximum depthof

_{litter above the waterline in a tree hole. A}

laboratory-57. 0cm(range22- 171 cm). reared adult emerged after 15 days in the pupal stage. Nine species of insects were

_frequently

Adults were collected in tree hole emergence traps from encountered in the 44 tree holes surveyed and are the end of April until _early

_July,

1985. Emergence included inthelistofdendrolimnetobiontinsects from _{trapping showed a rather synchronous emergence} the _study area (TABLE 1). A description of each _{pattern in each tree hole with a single collective}

follows. emergence peak(

_Fig.

2A). Mallota posticata, another

tree- hole inhabiting syrphid is known to be univoltine

Blerahumeralis Maier 1978).

The adults of this syrphid have been collected in

Washington, Idaho, Oregon,andCalifornia( Cole 1969) Limnophyes hamiltoni

and werefirstdescribed

_by

Williston(1882).Adultsare

_{Adults of this midge were originally described by}

brown with numerous yellow areas that include the

_{Saether( 1969). They are ca. 2 mm in total body length.}

humeriandbasal halvesofthe femora. Although the

_{The Lake County records from this study represent a}

adults weredescribedover100yearsago,priorto this considerable extension in the known range of the studytheimmaturesand theirlife

_history

were unknown

_{species. Saether( 1984) recently reported collection of}

F. C.Thompson,pers.commun.). L. hamiltoni in South Carolina. Prior records are from Larvae were collected ina_truly aquaticsituation Greenland and Alaska as well as the Northwest and

in freewaterorin detritusbeneathfreewater)inthe tree Yukon Territories and British Columbia, Canada. In

holes. Themature larvaeare 15-18 mm

_long

with a

_{addition, L. hamiltoni is probably a synonym of a}

breathing

tube thatcan beextendedtoover60mmin

_{Paleartic species with several earlier names including}

length. Maier (1978) reportedthatMallotaposticata Limnophyes smolandicus and Limnophyes vernalis Fabricius),anothersyrphid

_fly

whoseimmaturesoccur ( Brundin 1947). Despite the extensive geographic

TABLE 1. Dendrolimnetobiont insects collected from water- filled tree holes in oak woodlands in northern California.

Order

_Family

Genus Species

Diptera Syrphidae Blera humeralis( Williston)

Chironomidae Limnophyes hamiltoni Saether

Polypedilum pedatum excelsius Townes

Ceratopogonidae CulicoidesneofagineusWirth& Blanton

CulicoidescavaticusWirth& Jones

Culicidae Aedes sierrensis( Ludlow)

Orthopodomyia signifera( Coquillett)

Psychodidae

_{Telmatoscopus sp.( undescribed)}

DECEMBER, 1988 BULL. SOC. VECTOR ECOL. ₂₂₅ 12 A

1

10 ELENA a 8 CYPNON

1

J cs u. e

1

0

ac

US 4 2

11

O 60 46

he

US 40

W

3

36 POL YPEO/L UM

W

CL

07 30 _{L/ MNOPNYES} J o= 26

au-

20

m15

10 j/ \ 5 0 30 C. C4VA77CUS C 25 C. NEOPAC/NEUS CE a 20 - 7ZZA447t7SCCCPUS 1•J 16 -t

U-0

10

W

m

z

6 l

MAR APR MAY JUN JUL AUG

Figure 2.

_{Numbers of adult dendrolimnetobiont insects( excluding Culicidae) caught in emergence traps over}

15 pans in northern California oak woodlands from March 28 to September 2, 1985. A) Blera

humeralis and Cyphon sp., B) Polypedilumpedatum ecelsius and Limnophyes hamiltoni, C) Culicoides

cavaticus,Culicoides neofagineus, and_{Telmatoscopus sp.(} threepoint_runningmeans).

226 BULL.SOC.VECTOR ECOL. DECEMBER, 1988

range known for this species, all of the previous water-filled tree holes. Each of these holes contained

collections wereofadults, thelarvaeandtheirhabitat

_{Limnophyes larvae. Sweep net collections were made}

being

unknown (D. R. Oliver, pers. commun.).

_{from one of those swarms. Forty-six males and eight}

Grodhaus and Rotramel ( 1980) previously reported

females were collected and counted in the laboratory.

collection of Limnophyes larvae from northern

_{Adult production of L. hamiltoni from overwintering}

California tree holes but _they did not

_identify

the larval populations in trapped tree holes ceased in

mid-species.

June 1985( Fig. 2B), earlier than any other of the

tree-Withintheconfines ofthe_studyareas examined,L.

_{hole inhabiting insects studied.}

hamiltoni immatures are apparently largely restricted to

water-filled tree holes. Other species in the genus Polypedilum pedatum excelsius

inhabitthemarginsandshallowregions ofalltypesof Polypedilum pedatum excelsius and Polypedilum

fresh waterand somelive in

_damp

terrestrialhabitats pedatum pedatum are the western and eastern North

OliverandRoussel 1983). Searchesof

_damp

terrestrial

_{American forms, respectively, of the same species}

habitatsand moistleaf litterinthestudyareasdidnot ( Townes 1945). Polypedilum pedatum excelsius has

resultin locationofLimnophyes larvaeoutside of water- been collected from Washington and California( Cole

filledtree holes. Larvae were common inpans of

_Q.

1969). Grodhaus and Rotramel( 1980) described all the

kelloggii,

Q.

wislizenii, andA. menziesiibutwerenot immature life stages and reported larval habitats and life

foundin

_Q.

lobatarotholes( TABLE2). Noadultswere

_{history of the western subspecies. All of their records of}

collectedfrom

Q.

lobatapans( TABLE 3).

larval habitats are from oak ( Q. kelloggii, Q. lobata,

Limnophyes larvae are sprawlers ( Merritt and Quercus agrifolia [Neel]) and laurel ( Umbellularia Cummins 1984) andwere most commonintreeholes californica[ Hooker and Amott]) tree holes except for a that were_{nearly filled} withleaves anddebris. Larval single collection from wet leaf litter at the edge of a gut-content analyses(n=21)showed thedigestivetracts _spring under oak and laurel trees. Larvae of most

containeddetritusparticlesandtoalesserextentfungal species in the genus live in bottom substrate, often hyphae.Pupaewerefoundatthewatersurfaceofsome associated with plant debris( Oliver and Roussel 1983).

treeholes. Neither larvaenor pupae wereeverfound in

In the present study, larvae were most frequently

tubesor cocoons. collected from A. menziesii tree holes ( TABLE 2).

Swarms ofadultL. hamiltoni were observed on

_{Adults were collected only from pans of A. menziesii}

February

27, 1985,_circlingabovetheopeningsoftwo ( TABLE 3).

TABLE 2. Percentages of tree holes positive for immature dendrolimnetobiont insects in the various tree species

of oak woodlands in northern California in 1983- 85.

Pans Rot holes

Quercus Quercus Arbutus Quercus All

Organism kelloggii(32)* wislizenii(4) menziesii(3) lobata(5) tree holes( 44)

Aedessierrensis 100.0 100. 0 100.0 100.0 100.0

Orthopodomyiasignifera 3.1 0. 0 0. 0 60.0 9. 1

Culicoides spp. 96.9 100. 0 100.0 100.0 97. 7

Blera humeralis 15. 6 75. 0 66.7 40.0 27. 3

Polypedilumpedatum excelsius 3.1 25. 0 66.7 0. 0 9. 1

Limnophyes hamiltoni 46.9 75.0 100.0 0.0 47.7

Telmatoscopus sp. 37.5 75. 0 66.7 0.0 38. 6

Cyphon sp. 12.5 0.0 0.0 60.0 15. 9

DECEMBER, 1988 BULL. SOC. VECTOR ECOL. 227

TABLE 3. Numbers of adult insects collected from emergence traps over 15 pans from March 28 to September

2, 1985. y h c p, by

P;

Arbutusmenziesii 1 1331 0 17 3 295 2 5 0 2 10 0 8 49 67 3 5 0 3 13 0 16 4 0 1 17 0 Quercuswislizenii 1 4 0 3 1 0 2 0 0 2 102 3 29 6 0 10 0 0 3 1403 2 25 2 0 0 0 0 4 201 1 89 0 0 0 11 0 Quercus kelloggii 1 16 16 0 1 0 0 9 12 2 193 10 20 0 0 6 15 0 3 527 23 25 0 0 0 14 55 4 28 0 58 0 0 1 4 0 5 101 0 2 2 0 0 0 0 Quercus lobata 1 452 0 0 0 0 0 0 0 2 7 0 26 0 0 0 0 0 3 14 0 0 0 0 0 1 0

Alltreespecies x 293. 5 3. 7 21.2 4.5 24. 1 1.7 5.4 4. 5

Live fourth_{instar P. p.}excelsiuslarvaeareblood

_{inhabiting culicids in the study area have been}

redincolor. Larvaeconstructtubesonleavesand other

extensively studied. _{A few of the important Ae.}

treehole debrisandwere_veryseldom collected outside _{sierrenis studies are cited in the introduction. Chapman} of them. Near the end of summer,live larvae canbe (

1964) and Zavortink( 1985) have studied the biology

collectedfromsometreeholeswhichhave lacked free

_{and ecology of Or. signifera. The range ofAe. sierrensis}

waterfor overtwo months (Grodhaus and Rotramel _{includes much of western North America from British}

1980).

_During

the wet season, larval gut-content

_{Columbia to Baja California. Orthopodomyia signifera}

analyses(n=11) showedthedigestivetracts tocontain

_{has been found in most of temperate North America.}

flagellate protozoans, fungal hyphae, and detritus

_{Both are largely restricted to tree holes ( Bohan and}

particles. _{Washino 1978). Tree hole Aedes larvae in the}

Adultswerecapturedintree-holeemergencetraps

_{southwestern United States feed by filtering, browsing,}

from the

_beginning

of April into late August, 1985. _{and gnawing ( Zavortink 1985). Orthopodomyia}

There were two _early season emergence peaks, the _{signifera larvae are filterfeeders- detritivores( Lounibos}

largest occurringneartheend of

_{May( Fig.}

2B). A later 1985).

season emergence peak coincided with

_drying

ofthe

_{Aedes sierrensis and Or. signifera larvae usually}

treeholes.

occur together only in permanent rain-filled tree holes.

Orthopodomyia signifera dominates permanent tree Aedessierrensis andOrthopodomyiasignifera

_{holes filled with fluids secreted by the plant( e.g., some}

The

_biology

and ecology of the two tree hole willowsand cottonwoods) andAe. sierrensisdominates

228 BULL. SOC. VECTOR ECOL. DECEMBER, 1988

temporaryrain-filledtreeholes( Zavortink 1985). Each

_{Culicoides cavaticus and Culicoides neofagineus}

oftherotholecollections ofOr.signiferainthis_study

_{The larvae of these two species are undescribed}

occurredin

_deep

holeswithrestricted openingswhich

_{and indistinguishable from each other ( W. Wirth, pers.}

allowedrainwatertoremainintheholethrough atleast commun.).

_{Adults are markedly different in appearance}

mostofthe

_dry

summerperiod.Water inthese treeholes

_{and easily distinguished by using the descriptions of}

is of high pH (mean=8.12) and _conductivity

_{Wirth and Jones( 1956) for C. cavaticus and Wirth and}

mean=2937 µmhos/cm) and _very dark in color. Blanton ( 1969) for C. neofagineus. Larvae of each Nonetheless, the Or. signifera larvae collected from

_{species have only been reported from tree hole habitats.}

these holes were pink in color

_indicating

_they had

_{The feeding habits of adult females of each species are}

ingestedthephotosyntheticbacteriaThiocapsa( Bohart

_{poorly known but C. neofagineus has been collected}

andWashino 1978). _{In only}onetreehole,a

_Q.

lobata _{from the ears of deer and in quail- baited traps( Wirth and} rotholewithadepthof171cm,did Or.signiferalarvae Blanton 1969).

The known range of each species

outnumberAe.sierrensislarvae. includes parts of Arizona, California, and Oregon

Aedes sierrensis adults were collected in ( _{Wirth et al. 1985). Emergence traps were placed on 15} emergence trapsfrom the first week of April to the

_{pans in 1985 and 13 produced Culicoides adults. Five}

secondweekofAugust, 1985. Maleemergence showed _{produced adults of both species, seven produced C.} a_strongpeakin April. Female emergencewasmore

_{cavaticus only, and one produced C. neofagineus only}

evenfrom AprilthroughJune,thendeclinedand ended ( TABLE 3).

inmid-August(

_Fig.

3). Maleadults were59. 9percent _{In 1985, adults of each species emerged into} tree-of thetotalemergencefromthe15panstrappedoverthe _{hole traps in the first week of April. Culicoides}

cavati-entire 1985season. Notrapswereemployed overtree

_{cus showed strong emergence peaks in early spring and}

holes_{containing Or.}signiferalarvae in 1985, butina

_{as the tree holes dried near the end of July. Culicoides}

separate_studyin 1986,oneA.menziesiirotholewitha _{neofagineus showed similar but less marked}

emer-smallpopulationofOr.signiferalarvaewasmonitored gence peaks.

_{Emergence occurred from early April}

with anemergence_trap. Adultsemergedprimarilyin

_{until the tree holes dried at the end of August ( Fig.}

themonths ofSeptemberandOctober. 2C).

900 SO-MALES 700- FEMALES W 600-3 600-4 400-O 1

52

r Zoo

I \\

100- V o

MAR APR MAY JUN JUL AUG

Figure 3. Numbers of male and female Aedes sierrensis caught in emergence traps over 15 pans in oak

DECEMBER, 1988 BULL. SOC.VECTOR ECOL. ₂₂₉

ClarkandFukuda(1967)reported predation

_by

C.

_{in the laboratory were found to contain large particle}

cavaticus larvae upon Ae. sierrensis larvae. Their

_{tree hole detritus, flagellate protozoans, and fungi.}

observationsweremadeinthe

_laboratory

inwaterfree

_{Adults emerged into tree hole traps from early April}

from any debris,and whenalfalfa pellets were added, until September in 1985 (

_Fig.

2C). The emergence

predation wasno longer observed. Hair and Turner

pattern of overwintering larvae is similar to that of the

1966) reported that larvae of Culicoidesguttipennis

_{Culicoides spp. and shows small spring and late summer}

Coquillett), a treehole speciesin theeasternUnited _{emergence peaks.}

States, sometimes feed upon live Aedes triseriatus

These flies are easy to maintain in the laboratory. A

Say),

Or.signifera,andhelodid larvae.

self-perpetuating colony can be maintained by placing

The digestive tracts of _{Culicoides spp. larvae}

_{larvae, tree hole water, and leaves in a petri dish in a}

n=21)collectedinthestudyareawerefoundtocontain

small cage. Females lay cream colored cylindrical

fineparticledetritus, flagellateprotozoans, and smaller _{eggs on leaves on the surface of the water which hatch}

volumes offungalparts. Thegutsofsomelarvaealso

within two days. No evidence of delayed hatching or

contained afewalgalcells. Inthe

_laboratory,

predation

desiccation- resistant( aestivating) eggs was found. One

wasnot observedupon_{any larval instar in beakers,}each

liter of airspace is sufficient to maintain mating and

containing 10 Culicoides larvaeand 10 Ae.sierrensis

_{oviposition. In the absence of other tree hole species,}

larvae. After48 hours, Ae.sierrensislarvalmortality

_{larval density often became very heavy in the laboratory}

averaged7. 0percentinthe 10replicatesthatincluded

colony but was always relatively sparse in the tree holes

Culicoides larvae. Control mortality

during

thesame surveyed.

period averaged 5. 0 percent. There was no significant difference (Student's t-test, P>0.05) in Ae. sierrensis

Cyphon sp.( undescribed)

mortalitybetween beakerscontaining Culicoides larvae

_{This beetle is the only non- dipteran insect among}

andcontrolreplicates. Culicoides larvaeusedforgut-

the dendrolimnetobiont fauna in the study area. The

content analyses and

_laboratory

bioassays were _{range of this undescribed species is}

unknown. In collectedfromtree ho!eswhichproduced adults ofC.

_{addition to the Lake County records from this study,}

cavaticus_{only, C.}neofagineus_only,andbothspecies. _{there is a single adult specimen from Crater Lake}

National Park, Oregon in the collection of the U. S.

Telmatoscopussp.( undescribed)

_{National Museum. Based on comparisons of the adult}

Thegeographic rangeofthisundescribed

_fly

isnot _{genitalia and the presence of subbasal pronotal} known outside of Lake and Mendocino Counties. _{depressions, this undescribed species is thought to be}

Adults have beenexamined

_by

Dr. Derek Duckhouse,

_{closely related to the eastern North American species,}

whoplacesthespeciesinthe genusClogmia. Quateand _{Cyphon americana Pic and Cyphon cooperi Schaeffer.} Quate ( 1967) recognized Clogmia as a subgenus of

_{Females can be separated from described members of}

Telmatoscopus. At that time, Duckhouse also

_{the genus by the presence of two contiguous pits on the}

recognized Clogmiaatthe subgeneric level, but later

_{last ventral abdominal segment, each containing}

dark-Duckhouse( 1974) elevatedittofullgenus. Quateand

pigmented sensory hairs. A description of this taxon is

Vockeroth(1981) stillhadnot recognized genericlevel _{in preparation( G. Kennen, pers. commun.).}

for Clogmia, so the

_fly

is listed hereunderthename _{Larvae are crawlers and can be collected on the} more _widely used in North America. Most of the _{walls of the tree holes as well as in detritus at the bottom.}

Clogmia spp.areAustralianandAsian but inadditionto

_{In the laboratory, larvae pupate in leaf litter or crevices}

this undescribed species, macdonaldi Quate, _{in bark above the water line. Larvae of all instars can be} albipunctata Williston, and superbus Banks have _{collected from moist detritus in the bottom of tree holes}

Nearctic distributions. The species collected in this _{with no free water at the end of summer. Pupae have}

study is closelyrelatedtomacdonaldi_{but apparently is}

four long spines on the pronotum similar to those

not conspecific. Duckhouse ( 1978) reportedthat the _{reported for Prionocyphon limbatus LeConte ( Leech} larvae of_{Clogmia spp.} occur _mostly in treeholes or _{andChandler 1956). In 1985, adult emergence did not}

plant containers. This undescribed species was

commence until the tree holes began to dry up.

collectedfrompans of allfourtreespecies examinedbut

_{Emergence of adults peaked at the end of July( Fig. 2A).}

wasabsentin

_Q.

lobatarotholes( TABLES 2and3). _{The single emergence peak, coupled with observations} The larvaeofthis psychodid areburrowers inthe

_{during the study that all larval instars are present in tree}

detritus intreeholes.

_They

arefoundmost_commonly

_{holes during all of the yearly seasons, suggest that this}

inshallowtreeholeswithlargeamountsofleaf litter.

species may spend more than one year in the larval

The digestivetractsof14larvae dissectedand analyzed _stages.

230 BULL. SOC. VECTOR ECOL. _{DECEMBER, 1988}

morethan oneyearis implied foraEuropean helodid

_{contained depressions or ledges above the waterline}

Prionocyphon serricornis Muller). He found that

which contained moist leaf litter. Insects occasionally

larvaldensities were similar allyear intreeholes and

_{collected from tree holes during this study which are not}

that_{larvae live up}to twoyearsinthe

_laboratory.

_{dendrolimnetobionts included Culiseta incidens}

Peterson ( 1960) stated that helodid larvae are (

_{Culicidae), Tipula( Tipulidae), Rhagio( Rhagionidae),}

predaceousbut other authors (

_Kitching

1971, Merritt Dasyhelea ( _{Ceratopogonidae), and Empididae.} and Cummins 1984) refer to themas saprophages or

Collembolans, including Sminthurides( Sminthuridae)

herbivores. Gut-content analyses of larvae of this

_{and Isotomidae, were also present in some tree holes.}

Cyphon sp. (n=18) showed the larval diet to consist

_{Physical and water quality parameters of 15 pans}

mainly of detritus particles and fungi. A small

_{used for analyses of adult insect production over an}

percentage ofthedietconsisted offlagellateprotozoans entire season are presented in TABLE 4. Quercus

and, in one treehole, submergedlichens. Larvaeare

_{lobata pans had relatively small mean surface area, low}

easily reared to adults in the

_laboratory

without the

_{mean leaf litter weight, high mean pH, and high}

presence ofpotential_preyspecies. _{conductivity compared to the other tree species}

measured. Quercus wislizenii pans had relatively low

DISCUSSION

mean pH and conductivity and were the shallowest pans

studied. Tree holes with high pH and conductivity had

Although all the insect surveys were qualitative, _{nearly opaque coffee- colored water. Water in acidic} Ae. sierrensiswas the most prevalent andCulicoides

_{tree holes was transparent with a light brown tinge.}

spp. were the second most encountered immature

_{Emergence trap data from each of the 15 pans are}

insects inthesurveys. Thesetwogenera were alsothe

_{presented in TABLE 3. These collections demonstrate}

most prevalentintermsof numbers oftreeholespositive

_{the dominance of Ae. sierrensis in terms of numbers of}

for their presence (TABLE2). _{Culicoides spp.} were

_{adult insects per tree hole. Each tree hole produced an}

found in 43 of the 44 tree holes surveyed andAe.

_{average of nearly 300 Ae. sierrensis adults, over 81}

sierrensis wasfound inallofthem. Thechironomids _{percent of the total number of adult dendrolimnetobiont}

and psychodids were absent from allof therotholes insects produced

_by

the tree holes. Garcia and

sampled. Allwere more prevalentintheshallower pans

_{DesRochers( 1976) reported that the numbers of adult}

which_{usually had}leaf litter_nearlyto thesurface ofthe

_{Ae. sierrensis produced by a tree hole may be as little as}

water. Polypedilum pedatumexcelsius was therarer

_{2.5 percent of the first instar larvae which initially}

chironomid but all of the tree holes positive for its

_{hatched in that hole. The data in TABLE 3 do not,}

presence also containedL. hamiltoni. The

_frequency

of

_{however, indicate the potential total seasonal output of}

occurrence of larvae was _{significantly higher in} the

_{adult insects from the trapped tree holes since the traps}

deeper rot holes than in pans for both Cyphon (chi-

_{prevented oviposition during the season by any species}

square P< 0. 01) and Or. signifera (P< 0. 001). _{which are multivoltive. Also, some emergence of L.} Orthopodomyia signifera_usually occurs _{only in} tree

_{hamiltoni occurred before traps were placed over the}

holes that hold water all year (Bohan and Washino tree hole openings.

1978). Cyphonadults emerged_{very late in}theseason

_{Each of the 15 pans produced an average of 4. 1}

after most oftheshallowtreeholeswere

_dry.

Thereis

_{dendrolimnetobiont insect species with a range of 1 to}

also evidencethatsomehelodidsrequire two yearsin

_{6 species per tree hole. Surface area of the tree hole and}

the larval stage (

_Kitching

1971). Blera humeralis

_{leaf litter weight were both positively correlated with}

occurredwithsimilar

_frequency

inbothpans and rot _{the number of species per tree hole( TABLE 5). Surface} holes.

area is probably the most important physical factor

In addition to _{dendrolimnetobionts, Rohnert}

_{measured since it may influence other factors. Surface}

1950) and

_{Kitching (}

1971) have described other

_{area is positively correlated with leaf litter weight}

classifications ofinsectssometimes collectedinwater- (

_{linear correlation coefficient=0. 89, Student' s t test,}

filledtreeholes. These includegeneralists attractedto P<0. 05).

Large surface area allows more leaf litter to

a wide range ofhabitatsand not

_largely

restrictedto tree

_{accumulate in a tree hole, which increases the nutrient}

holes and otherinsects that _{occasionally occupy} tree

_{base of the community and provides a habitat for the}

holes

_by

accident. Snow ( 1958) analyzedthe spatial

_{sprawlers, burrowers, crawlers, and tube builders.}

distributionofinsects inawater-filledtreeholeandin

_{Large surface area also allows more dilution of water in}

addition to theaquatichabitat describeda numberof

_{the tree hole with rainwater. Of the physical factors}

other

_dry,

moist, and semi- aquatichabitats withinthe

_{measured, only leaf litter weight was significantly}

treehole. Thetreeholes examinedinthis_studyoften correlatedwithtotal adultinsectproduction.

DECEMBER, 1988 BULL. SOC. VECTOR ECOL.

231

TABLE4.

Mean physical and water quality measurements of 15 pans taken between March 18- 25, 1985 in Lake

and Mendocino Counties, CA ( 3- 10 days before emergence traps were placed over the tree hole

openings).

Arbutusmenziesii Quercuswislizenii Quercuskelloggii

_{Quercus lobata}

NumberofTrees _{3 4 5} 3 Surfacearea( cm2) 390. 70 ( 160- 570)* 150.00 ( 36- 294) 251. 40( 198-525) 47. 00( 24- 81) Maximumdepth(cm) 10.50 ( 7- 12) 7. 00 ( 4- 11) 19. 40 ( 9- 29) 12. 20 ( 8- 20) Maximumvolume(1) 4. 70 ( 0. 7- 10. 2) 1.60 ( 0.4- 4.6) 8. 70 (1.0- 24.6) _{3. 10 ( 0.7- 5. 6)} Leaf litterweight(_g) 1003. 30 ( 100- 1570) 370. 00 ( 100-950) 534. 00 (105-865) 40.70 ( 10- 62)

pH 6.82 (6. 78- 6.87) 6.31 ( 5.94- 6.74) _{7. 15 ( 6. 82- 7. 65) 8. 10 ( 7. 61- 8.48)}

Conductivity(µ

mhos/ cm) 566 ( 413- 832) 424 ( 187-913) 905 ( 183- 2041) _{3014 ( 1492- 4780)}

Numbers in parentheses are the range of the parameter measured.

Snow( 1958)studied awater-_{filled stump in Illinois}

have been reported in the tree hole habitat. The absence

andproducedthe_onlyprevious specieslistoftreehole

of a predatory culicid in northern California may be

insectfauna fromtemperate_{North America. The only}

related to the hypothesis that fewer trophic levels may

species common tohis listand later identified inthis

occur in tree hole community systems which experience

study is Or. signifera. A _predatoryculicid,Toxoryn-

more environmental perturbations ( Kitching 1983).

chites rutilus septentrionalis(DyarandKnab),wasalso

_{Regions where rainfall, desiccation, and leaf fall are less}

listed

_by

Snow. The Illinoistreehole_communitywas

seasonal may support more trophic levels than occur in

similar to that ofnorthern California in

_having

one _{northern California tree holes.}

detritivorousaedine mosquito(Aedestriseriatus),one

_{The nine species of insects in the northern}

syrphid (Meromarcus acutus [Fabricius]), two

California tree holes studied are all primarily

ceratopogonids ( Culicoides guttipennis [ Coquillett]

_{detritivores or saprophages. To the limited extent that}

andCulicoidesarboricolaRootandHoffman),and one

_{some species feed upon photosynthetic bacteria or}

helodid (Prionocyphon discoides [

_Say]).

The major

algae, some energy utilized by the dendrolimnetobiont

differences between the two tree hole insect

_{insect community is not detritus based. The literature}

communities are the presence of two chironomid

_{indicates that C. cavaticus can be an occasional predator}

species in northern California and the presence of a

but gut analyses and preliminary laboratory

predatoryculicidin Illinois. NorthernCaliforniaisthe

experiments did not indicate that any of the associated

only area ofNorth America fromwhichchironomids

species consume many Ae. sierrensis larvae. However,

TABLE 5.

Spearman's correlation coefficient( rho) for physical factors affecting number of dendrolimnetobiont

species and adult insect production from 15 pans trapped from March 28 to September 2, 1985.

Surface Tree hole Tree hole Leaf

Numberper _{Area Depth Volume Litter}

Conductivity

Tree Hole cm2) cm) cm3) wt.(_g) pH (µ mhos/ cm) NumberofSpecies 0. 7767* 0. 1170 0.1661 0. 7750* - 0. 3866 - 0. 2393 Numberof_{Adults 0. 3848 0. 0098 0. 1643} 0.5384* - 0.3866 - 0. 2179 Significant Spearman's rank correlationcoefficient(P< 0. 05).

232 BULL. SOC.VECTORECOL. DECEMBER, 1988

most of these _cohabiting populations could at times Cole, F. R. 1969. The flies of western North America.

competefor foodor spaceintheserestrictedhabitats. In

Univ. Calif. Press, Berkeley, 693 pp.

a similar tree hole community in beech trees in England

also

_lacking

predators),

_{Kitching (}

1983) concluded Duckhouse, D. A. 1974. Redescription of the

thatthedetritus- basedresourcesare partitioned

by

the neotropical Psychodidae ( Diptera, Nematocera) tree-holeinhabitants

largely

basedontheparticle size

described by Rapp and Curran. J. Entomol. ( B)

utilized as wellas spatial andtemporal means. The 43( 1): 55- 62.

interrelationships of the various tree hole species in

northernCaliforniaareunknownand the_community Duckhouse, D. A. 1978. Non- phlebotomine

warrantsfurther study. Psychodidae ( Diptera, Nematocera) of southern

Africa, II. Subfamily Psychodinae: Neoarisemus

Acknowledgements and the brunettoid and telmatoscopoid genera.

Ann. Natal Mus. 23( 2): 305- 359.

The identifications

done by the following

taxonomistswere essentialforthis_studyand aregreatly Egerter, D. E. and J. R. Anderson. 1985. Infection of appreciated: Mr. Gail Grodhaus, California the western tree hole mosquito, Aedes sierrensis DepartmentofHealthServices,

Berkeley,(

Culicoides Diptera: Culicidae), with Lambornella clarki andPolypedilum),Dr.Charles Hogue, Natural

History

Ciliophora: Tetrahymenidae). J. Invert. Pathol. Museum of Los Angeles

County,

Los Angeles, 46: 296- 304.

California( Blera and Telmatoscopus), Dr. Don Oliver,

Biosystematics Research Institute, Agriculture Canada,

Fish, D. 1983. Phytotelmata: flora and fauna. Pp.

1-Ottawa,Canada( Limnophyes), Dr. DerekDuckhouse,

28 in Phytotelmata: Terrestrial Plants as Hosts for

University

of Adelaide, Adelaide, Australia

Aquatic Insect Communities( J. H. Frank and L. P.

Telmatoscopus), Dr. F. Christian Thompson, Lounibos,eds.).

Plexus Publishing, Inc., Medford,

Systematic

Entomology

Laboratory,

U. S. D.A.,

_{304 pp.}

Washington, D.C., ( Blera),

and Mr. Gary Kennen,

Stony

Brook, New York ( Cyphon). Information

Garcia, R. and G. Ponting. 1972. Studies on the ecology

provided

_by

Dr.Willis Wirth,Systematic

Entomology

of the treehole mosquito Aedes sierrensis (

Lud-Laboratory,

U.S.D. A., Washington, D.C. is also low).

Proc. Calif. Mosq. Contr. Assoc. 40: 63- 65.

gratefully acknowledged. We thank Joann Haberthur,

AlbertReuss,andLewisTurlingtonoftheLake

_County

Garcia, R. and B. S. DesRochers. 1976. Natural

MosquitoAbatementDistrictfortheircooperation. attrition in larval populations of the treehole mosquitoAedessierrensis(Ludlow). Proc. Calif.

REFERENCES CITED

Mosq. Contr. Assoc. 44: 46.

Bohart, R. M.andR.K. Washino. 1978. Mosquitoesof Grodhaus, G. and G. L. Rotramel. 1980. Immature

California. 3rd Ed., Div. Agri. Sci., Univ. Calif. stages of Polypedilum pedatum excelsius( Diptera, Press,

_Berkeley,

153pp.

Chironomidae) from seasonally flooded tree holes.

ActaUniversitatis Carolinae- Biologica 1978: 69-Brundin, L. 1947. Zur kenntnis derschwedischen 76.

Chironomoden. Arkiv.Zool.39A(3): 1- 95.

Hair, J. A. and E. C. Turner, Jr.

_{1966. Laboratory}

Chapman,H. C. 1964. Observationsonthe

_biology

and colonization and mass- production procedures for ecology of Orthopodomyia californica Bohart.

Culicoides guttipennis. Mosq. News 26( 3):

429-Mosq.

News24( 4): 432-439. 433.

Clark, T. B.andD.G.Brandl. 1976. Observationson Hanson, R. P. and M. G. Hanson. 1970. The effect of

the infection of Aedes sierrensis

_by

a land use practices on the vector of California tetrahymenineciliate. J.Invert.Path. 23:341-349. Encephalitis ( LaCrosse) in north central United

States. Mosq. News 30( 2): 215- 221.

Clark, T. B. and T. Fukuda. 1967. Predation of

Culi-coides cavaticus(WirthandJones) larvaeonAedes

Hawley, W. A. 1985. Population dynamics of Aedes

sierrensis(Ludlow).

Mosq.

News27( 3):424-425. sierrensis.

_Pp.

167- 184in

Ecology

ofMosquitoes:

DECEMBER, 1988 BULL. SOC. VECTOR ECOL. ₂₃₃

Proceedingsof a

_Workshop(

L. P. Lounibos, J. R.

_{Papineau, E. A. 1984. Controlling Aedes sierrensis in}

Rey,

and J. H. Frank, eds.). Florida Medical Jackson

_County,

a year-round program. Proc.

Entomology Laboratory,

Vero Beach, 579 pp.

_{Calif. Mosq. Contr. Assoc. 52: 63- 67.}

Jenkins, D. W.andS. J. Carpenter. 1946.

_Ecology

of

_{Peterson, A. 1960. Larvae of Insects: An introduction}

the tree hole

_breeding

mosquitoes of Nearctic

_{to Nearctic species, Part H: Coleoptera, Diptera,}

North America. Ecological Monographs, 16( 1): _{Neuroptera, Siphonaptera, Mecoptera,} 32-47.

Trichoptera. 2nd ed., Columbus, 416 pp.

Kitching,

R. L. 1971. Anecological _studyofwater-

_{Quate, L. W. and S. H. Quate. 1967. A monograph of}

filledtree-holesandtheirpositioninthewoodland Papuan Psychodidae,

_{including Phlebotomus}

ecosystem. J.AnimalEcol. 40: 281- 302. Diptera).

Pacif. Insects Monograph 15: 1- 216.

Kitching,

R.L. 1983.

_Community

structureinwater-

_{Quate, L. W. and J. R. Vockeroth. 1981. Psychodidae.}

filled treeholes in Europe and Australia -

_{Pp. 293- 300 in Manual of Nearctic Diptera, Vol. 1}

comparisons and speculations.

_Pp.

205- 222 in

_{J. F. McAlpine, B. V. Peterson, G. E. Shewell, H.}

Phytotelmata: Terrestrial Plants as Hosts for

_{J. Teskey, J. R. Vockeroth, and D. M. Wood, eds.).}

AquaticInsect Communities( J. H. FrankandL.P.

_{Agriculture Canada, Ottawa, 674 pp.}

Lounibos,eds.).

_{Plexus Publishing, Inc., Medford,}

304 pp.

_{Rohnert, U. 1950. Wasserfullte Baumhohlen and ihre}

Besiedlung.

Ein

_Beitrag

zur _Fauna

Kitching,

R.L.andC. Callaghan. 1981. The faunaof _{dendrolimnetica. Archiv fiir Hydrobiologie 44:}

water-filledtreeholes inabox forest insoutheast _{472- 516.}

Queensland. Australian Entomol. Mag. 8: 61- 70.

Saether, O. A. 1969.

_{Some Nearctic Podominae,}

Leech, H. B. and H. P. Chandler. 1956. Aquatic

_{Diamesinae, and Orthocladiinae ( Diptera:}

Chir-Coleoptera.

_Pp.

293- 371 in Aquatic Insects of _{onomidae). Fish Res. Board Can. Bull. 170: 1- 154.}

California( R. L. Usinger,ed.). Univ. Calif. Press,

Berkeley,

508 pp. Saether, O. A.

1984. Limnophyes er, new species

Diptera: Chironomidae) from Finland with new

Lounibos, L. P. 1985. Interactions

_influencing

_{Nearctic records of previously described species.}

production of tree hole mosquitoes in south _{Entomol. Scand. 15( 4): 540-544.}

Florida.

_{Pp. 65- 77 in Ecology of Mosquitoes:}

Proceedingsofa

_Workshop(

L.P.Lounibos, J. R. Samson, R. A. and G. G. Soares, Jr. 1984.

Rey,

and J. H. Frank, eds.). Florida Medical

_{Entomopathogenic species of the hyphomycete}

Entomology Laboratory,

Vero Beach, 579 pp.

genus Tolypocladium. J. Invert. Pathol. 43:

133-139.

Maier, C. T. 1978. The immature stages and biology of

Mallotaposticata(Fabricus)( Diptera: Syrphidae). Sanders, R. D.

_{1972. Microbial mortality factors in}

Proc. Entomol. Soc. Wash. 80( 3): 424-440.

Aedes sierrensis populations. Proc. Calif. Mosq.

Contr. Assoc. 40: 66- 68.

Merritt, R. W. and K. W. Cummins. 1984. An

introduction to the aquatic insects of North

_{Snow, W. E. 1958. Stratification of arthropods in a wet}

America. 2nd Ed., Kendall Hunt

_Publishing

Co.,

_{stump cavity. Ecology 39( 1): 83- 88.}

Dubuque, 721 pp.

Townes, H. K., Jr. 1945. The Nearctic species of

Munz, P. A. 1965. A California Flora. Univ.Calif. _{Tendipedini ( Diptera: Tendipedidae). Am. Midl.}

Press,

_Berkeley,

1681pp. Nat. 34: 1- 206.

Oliver,D.R.andM. E.Roussel. 1983. The insectsand _{Washburn, J. 0., M. E. Gross, D. R. Mercer, and J. R.} arachnids ofCanada, Part11: Thegenera oflarval _{Anderson. 1988. Predation- induced trophic shift}

midges of Canada ( Diptera: Chironomidae). of a free-

_living

ciliate: Parasitism of mosquito

234 BULL. SOC.VECTOR ECOL. DECEMBER, 1988

Weinmann, C. J. and R. Garcia. 1974. Canine American species of tree- hole Culicoides( Diptera:

heartworm in California, with observations on Heleidae). Proc. Entomol. Soc. Wash. 58( 3):

161-Aedessierrensisasapotential vector.Calif. Vector 168.

Views 21: 45- 50.

Wirth, W. W. and F. S. Blanton. 1969. North America

Williston,S. W. 1882. Contributiontoamonographof Culicoides of the pulicaris _{group ( Diptera:} theNorth American Syrphidae. Am. Phil. Soc. Ceratopogonidae). Fla. Entomol. 52(4):

207-Proc.20: 299- 332. 243.

Wirth,W.W.,A.L. Dyce,andB.V.Peterson. 1985.An

_{Zavortink, T. J. 1985. Observations on the ecology of}

atlasof_wingphotographs, withasummaryofthe treeholes and treehole mosquitoes in the

numerical characters of the Nearctic species of southwestern United States.

_{Pp. 473- 487 in}

Culicoides ( Diptera: Ceratopogonidae). Contr.

_Ecology

of Mosquitoes: Proceedings of a

Am. Entomol.Inst. 22( 4): 1- 46.

_{Workshop( L. P. Lounibos and J. H. Frank, eds.).}

Florida Medical Entomology Laboratory, Vero

Wirth, W. W.andR.H. Jones. 1956. ThreenewNorth Beach,_{579 pp.}

BULL. SOC. VECTOR ECOL.,13( 2): 235- 242 _{DECEMBER, 1988}

POPULATION TRENDS AND BEHAVIORAL ATTRIBUTES

OF ADULT MOSQUITOES ASSOCIATED WITH DAIRIES

IN SOUTHERN CALIFORNIA

E. T. Schreiber', M. S. Mulls' and J. D. Chaney'

ABSTRACT:

_{Studies relating to adult population trends and host- seeking activities were initiated at a dairy}

operation near Norco, Riverside County, California. The most prevalent species caught in dry ice surveillance traps

was Culex quinquefasciatus Say, followed by Culex erythrothorax Dyar and Culex tarsalis Coquillett. Species of

lesser importance were Culex peas Speiser, Anophelesfreeborn Aitken, and Culiseta particeps( Adams). Habitat

preferences were noted with respect to the species. However, no single one or two habitats were good indicators of

population trends through the season. The peak of host- seeking activity occurred one hour after sunset. Differences

were noted in the peak biting activity of individual species through most of the season. The majority of mosquitoes

captured were nulliparous, yet no differences in host-seeking behavior were noted with respect to parity throughout

nighttime activity.

INTRODUCTION _{these ponds often have low potential for mosquito} development( M. S. Dhillon, pers. commun.). Ecological and behavioral information on adult

_{Dairy operations with poor lagoon management, in}

CulextarsalisCoquillett, Culexquinquefasciatus

_Say,

_{addition to providing ideal development sites, have a}

and Culexpeus Speiser is pivotal _{in elucidating} the

_{copious supply of blood for host- seeking mosquitoes}

epidemiology of St. Louis encephalitis and western

_{since the cattle are nearby. Effects on milk production}

equine encephalitis(BohartandWashino1978)andfor

_{may occur if heavy populations exist. In Louisiana,}

developing

practical controlmethodologiesinsouthern

_{Steelman et al.( 1972, 1973) found weight reduction in}

California.

_{Additionally,}

characteristics ofthe adult _{levels of Hereford and Brahman breed steers due to} ecology and behaviorofthe various species mustbe

_{mosquito feeding.}

understoodtoaidinthe

_discovery

anddevelopmentof _{Seasonal abundance for mosquitoes varies with}

natural and chemical pestcontrolstrategies. _{respect to species. For instance, Culex erythrothorax}

In

_dairy

operations, cows are washed prior to

has been found to have its peak adult abundance in the

milking,and _{milking is done}twoorthree times a

_day.

_{summer months in southern California( Seaman 1945),} In addition, manure troughs and the milk rooms are

_{and is associated with tule swamps or margins of ponds}

washedand cleaned

_daily.

Thewaste waterfrom both _{and rivers where larvae have been collected( Bohart and} operationsisremovedfromthebarnviapipes or open Washino 1978). Culex tarsalis Coquillett peaks, in

ditches to a single or a series of

_holding

ponds or

_{adult abundance, from May through November( Reeves}

lagoons. Thus, these

_dairy

lagoonsare enriched with _{et al. 1958) and develops in clean rather than polluted}

manure and organic plant material,_{potentially creating water. Culex quinquefasciatus, the southern house} mos-idealconditionsfor Cx.quinquefasciatus andCx.peus quito, has been found in higher numbers from August

development(Mullaet al.1987). These lagoonsrequire

_{through December and develops in a variety of habitats,}

constant surveillance and management(Steelmanet al.

_{including polluted water( Bohart and Washino 1978).}

1967, Womeldorfet al.1969,andWhitten1971).

_Dairy

_{Nightly patterns of biting activity of mosquitoes}

lagoonswithsome_surrounding vegetationhave been have been documented in California. Anopheles reported to produce

_heavy

mosquito populations

_{freeborni has peaks of activity near sunset and again}

Bailey

etal. 1954, Mullaet al. 1987). Onecultural near sunrise( Cope et al. 1986), whereas, Cx. tarsalis

practiceis to

_{dig deep}

well-managed manure

_holding

had a single peak at sunset( Nelson and Spadoni 1972).

ponds and control the _resulting vegetation with

_{Culiseta inornata generally feed at dusk but may}

chemicals. Whenthismanagement practiceisrealized,

_{demonstrate a minor level of feeding behavior during}

236 BULL.SOC. VECTOR ECOL. DECEMBER, 1988

the night (Barnard andMulla 1977). Culexerythro-

_{utilizing CDC traps and human hosts for 10 minute}

thoraxhas been noted to seek hosts

_during

the

_day

_landing

counts. Relative abundance and population Chapman 1962) in Nevada, andBeck( 1961) found in

_{oscillation in parity rates are presented graphically}

Utahthat _theyweremostactiveinthe_{evening hours, utilizing} a 365

_day

calendar (Julian dates).

Environ-whereas, in southernCalifornia _morning peaks were mental parameters, such as temperature, relative noted

_by

Copeetal.( 1986). _{Peak activity}ofCx.peus

_{humidity, and wind speed were recorded throughout}

has been hard to determine since this species feeds

_{each night of the study. Studies of the host- seeking}

primarilyon passeriformbirds(TempelisandWashino

_{activity of females in two different physiological states}

1967). nulliparous and parous) were taken from subsamples

Studies onthe relationship betweenhost- seeking

from the dry ice surveillance traps at Habitat 3 and

activity and physiological age have been _widely

_{Habitat 5. Parity rates were determined by dissection of}

documented. Noapparent_relationship between host- individual females of each species and examination of

seekingandphysiological statewasnotedwithrespect the tracheation of the ovaries( Detinova 1962). toAfricanmosquitospecies(Gilles 1957, Corbet1962), Statistical analysis of the data utilized linear

whileService(1969)noted a positive_relationshipwith

_{regression techniques for trap catch and prediction}

British mosquito species. In California, Nelson and

_{utility for monitoring population trends ( Sokal and}

Spadoni ( 1972) found that no differences in host- Rohlf 1981), Kendall' s coefficient of concordance for seeking activityexisted withrespectto_paritystatefor

_{peak blood feeding activity for the various time periods}

An. freeborni, Aedes vexans ( Meigen), Aedes through the night (Siegel 1956), and the G- test of

melanimonDyar,andCx. tarsalis.

_{independence to test parity host- seeking activities}

During

thepastseason, theadultmosquitoesina through the night( Sokal and Rohlf 1981).

dairy habitat near Norco, California were studied from

JunethroughDecember 1987. The dairies inthis area RESULTS AND DISCUSSION

are surrounded by urban areas and residential housing

which are encroaching upon these semi- agricultural

_{Mosquito species collected by CDC traps at the}

areas. Theobjectivesofthis_studyweretocharacterize

_{dairy during the 1987 season were predominantly Cx.}

adultseasonal populationtrends,spatialdistributionof erythrothorax, Cx. peus, Cx. quinquefasciatus, and Cx. adultsinand around a

_dairy

operation,thephysiological tarsalis. Other mosquitoes found in lower numbers

age profileoffemales

_during

theentireseason,andthe were An. freeborni and Culiseta particeps. Shifts in

nighttimeactivitypatternsofhost-_seekingadults. abundance of each species varied throughout the

season. However, Cx. quinquefasciatus was the most METHODSANDMATERIALS

_{prevalent species collected followed by Cx.}

erythro-thorax. Culex quinquefasciatus abundance had three The studyareawaslocatedat a

_dairy

1 kmwest of peaks:

_{the first in mid July, the second in early}

the_cityofNorco in Riverside

_County.

Thepredominant September, and the third in late October. The peaks in

mosquitoes atthis sitewereproduced_mainlyin

_dairy

September and October can be explained in part because lagoons,woodland pools, andintailwater.

_During

this

_{the lagoons were reflooded the week before monitoring}

study, five distinct habitats were monitored

_by

CDC

_{was initiated, thus, allowing for greater oviposition and}

traps: Habitat1, 0. 25kmeastofthe

_dairy

lagoonsina larval development. Culex erythrothorax( which does truck _{crop field; Habitat 2,} the

_dairy/

lagoon proper;

_{not develop in these lagoons) had peaks similar to Cx.}

Habitat 3, treerows adjacentto the

_dairy

andlagoons; quinquefasciatus throughout the season. These peaks Habitat 4, 20meterswestfromthelagoons intrees_along are due to some other yet unidentified environmental

the interface of the

_dairy

operation and an adjacent factors because their development has been reported to

horse/cattle pasture;Habitat5, 0.5 km fromthe

_dairy

in be in more permanent bodies of water that support tule ariparianhabitat withbackwaterfrom theSanta Ana growth. Culex peas and Cx. tarsalis had lower numbers

river. Ineachhabitat,twosites were usedto_traphost-

_{and both had peaks in mid July. Low numbers of Cx.}

seeking adult mosquitoes on a semi-monthly basis.

_{peus in the CO, traps has been reported by Reisen and}

Landing

and

_biting

_activity offemale mosquitoes at Pfuntner( 1987) and similar findings were shown in this

nightwasassessedinalocationnearthe

_dairy

lagoons

_{study. All species steadily declined with the onset of}

proper. Intheseexperiments, 12all-night studies were

_{winter, with only Cx. quinquefasciatus adults still active}

conducted to determine the activity patterns of adult

_{in the environment( Fig. 1).}

mosquitoes. Host- seeking female mosquitoes were Species composition and abundance varied little sampled at various time intervals

_during

the night, withrespecttolocationofthehabitatstrapped(TABLE