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1. GEiwRAL: BEST COPY AVAILABLE a. By the directionof DASG a medical exto-.ologicalsurveywas conducted on selected coral islets of the Ene,j’etakAtoll to determineall real and potential entomologicalproblems to be encounteredduring cleanup a fragile and unstablebiologicalcownunity. The introductionof higher animal life forms has been artifici~l. This situationhas c. A variety of factorshave successfullylimitedthe t!.cestablishment 1) Limited accessibilityof the islets. 3) Limited land area, breeding sites, appropriatefood sources ~d d. These factors have, for the most part, restrictedthe establishment of medically importantarthropodaon the islets. a. A total of 12 isletswere selected for surveillance.Selectionwas based on the followingcriteria: 2) Vegetation and structuralharbcmge. 3) @erational aspects related to cleanupmission. civilians and natives.,.
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breeding sites and harborages‘J;eresompled. Light traps were set out in areas where wind shelter\\’asprovided to s,amplenocturnalactivity. were sst in association\\’ithburrows,nests, high activityareas and equipment indigenou to the survey teams providedample work and scopicallywith the use of appropriatekeys. The followingisletswere sumcyecl: a. The predominant problem on the atoll is t.helargcpopulationof rats. ,I Two sp$cies of rats were noted, t
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the cxcepti.onof the islet of Eneliatak the rat populationre~checlthe “ maximum carrying of the islets sumeyecl. ,. ‘,,;. Mice, though not taken in traps, aye presenton the islets.“Evi~ence”;”~, signs of chm:ge. The po~ulationof mice on the individul islets is’.’”.-”,’ species. NO ticks or fleas ]Jerefound. Three methods ~trereUSe~ to ~~~ 3) Visual examinationof the ‘bodyand hair wit.hthe aid ofmaowifying ~ Lack of higher ectoparasiticpopulationis attributedto extremely. , limited contactwith other mamnali~n species. Variou species of ; stinging (aculeate)wasps are present on all of the islets. Polistes ~ L fuscatus-var.aurifer is the most aggressive. Ropalidiamarglnata Parasiticwasps of the fmnily Sphecidaewere also collected. “t In all cases the wasp populationsper islet is low. However, where present the wasps tend to be concentratedin small areas, For example,on the islet of Jcclrol(Rex) a P. fuscatus colony was located in a refrigeratorbuilding. The–colonywas olclbut - viable and nests varied in size from the diameter of a quarter to the size of a football. About 25 wasps were present in the refrigeratorbuilding and a “~ number were observed forn~irqin the area. The estimated living populationof the colony ;S ~em;een 100 and 150 wasps. Limited natural food sources ~nd high winds have severly restricted the numbers of wasps capable of survivingon the islets. Normal limited. Colonies arc thereforesmll anclfocal. They may usualVY be located in dense foliage,well shieldedfrom the wind and close to the ground. Some R. marginatawere observed nesting up tosix feet above ground on–th~l=e of the foliage. .-
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The wasps normally are not aggressiveand c?onot seek out or type stingswith a wheel-flair reactionand pain lastipg from ; althol]ghsome people recalledbeing stung 4 or s times. One . .- rcport of 20 stin[~scould not be confirmedand is considered - : unlikely. It shouldbe noted that aggressivereactionswere ;.~~ ponly noticed when the integrityand safety of the colony or ..;, - No mosquitoeswere col~ected though light traps, naturaZ canalartificial nesting stationswere l:secl.F~lrtllemore,interviewsindicatedno one has been bitten by a mosquito. High wi.nclsare the major factor restrictingthe establislwcntof mosquitopopulations. Spiders are present throughout-the atoll’s islets. Specimensof what appears to be the black wide:,’have been collectedby personnelof the MML though none ]{erefotmclduring this survey. The only island have been sent to the ]]is}]oj)-j~]useti~], other venomous spidersI]a\’ebeen reportedfrom or collectedfrom the Snakes are not present on EnewetakAtoll. Flies affecti;gman ~ppear limiteclto severalspecies of the genus Nluscaor hmse flies and sarcop>~y~{fleshflies). In most cases the zing areas are in and aro~md waste disposalsites. Pormlationsare is possible though not ljkely.d~!eto good sanitarypracticesam-l a. The rodent populationsrequire controlof the earliestpossibledate. Baiting with zinc phosphicleis the most acceptableto this writer. However other baits are available. A speci~l ‘annexto this report will be prepared with specificguidelineson baiting requirements. l). Bait stationscontainim zinc phosphide in a formulationacceptableto the rats should be used. Several prcbaits S}IOUIC1be tcstedvitlloutthe presence-of zinc phosphideto determinewhich is the most acceptable to the rats. Upon completionof prebaitingthe actual zinc phosphide bait shoulclbeemployed. Each islet shouldbe prebaited immediately prior to baiting.
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Prebait and bait stationsshould be placed’h the exact same Iocatiois.,”;’~. hours of their placementto limit contactwith non target,organisms.” “, The process of cleaningup the isletsby engineerswill itselfIitive”--.’,’,, and food sources.. This combined integratedcontrol should significantly reduce, but not &-adicatethe rodent population. Continuedsurveillance under the direct supervisionof a pro~cssionalentornolo~ist.Thereafter” ‘ number a.nclsize of the islets selecteclfor control. If control is “ ‘ required for the base camps of Loj\\’aand Enewetakonly, then approximately’ personnel and one Entomologist. imm,. Control on most or all of the islets may requirea minimumof 21 peop~e “’; to the islets by helicopter\(ouldreduce the time requirements. No specificcontrol is required for the wasps. However, certainprecautic are warranted for personnelworking in thick foliage. . . 2) Long sleeves and pants. ...- 3) :“No bright colored or pastel coloredclothingsuch as reds, yellows, 4) : Insect repellentsare of no value in protectingagainst.wasp.sand bet
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to work as a comparativelysmall number of insectshave been success-~ly~ in~roduceclon the atoll. It would be helpful if incomingcargo were:.. .1 b. Pest control on any large scale is not requiredfor any animal or insect
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body of a host organism such as a rat. s. A brand name of a rodent trap which . ii catches the an~mal alive and without injury. ..’ 6. L. mactans: The black wiclow spider. 7. Le~idopterous Larvae: Moth and butterfly catterpillers. Musca:8.. The genus of flies to which house flies belong. 9. p. fuscatus: See 10 below. 10. Polistes fuscatus Var. aurifer: A common variety of paper Typical sting of the paper wasp ~~’ eel klalr Reaction). 12. prebaiting: Positioning a bait without the presence of a poison to measure” the acceptability and consumption by the rodent to be controlled. Furthermore, it indicates if other non-target organisms will be attracted to it. Predator:‘“13., an,., Usually an animal which specifically seeks out. .-. 14. R. niarginata: See 15 below. .- ‘1S: Ropalidia “rnarginata: A common paper wasp Similar to the 16. SphecidaQ: A mud wasp which is predacious against spiders. ,. Normally, it does not sting man but is capable..., ‘.17.’ Vespidae: A large taxonomic group of wasps which include the
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of many wasps. one typically has a raised blanched center , across surrounded by a large red “~