LarryW. Price Department of Cleography Portland SrareUniversity Portland, Ofegon 97207
Grasshopperson Snowin the WallowaMountains, Oregon
Abstract
In 1979 tbe Pacific\o(h$,cst crperienccd one of lhc wolst grassh.4rpcfoutbreaKs on recor.i An ekiiudinal cxtcnsion of tltxt infcsrelion \\.:rs, ,h\rr\ ed Ir rhc V r tu\i J II, ,r,ni,n.. Or.g, rn, wnere grasstrolr pers *.crc iolrnd on sno$ rr alriruclcsof 2..150to 2,925 m jn cxfly July on thc norrh sicleof Eiigle (lap. Obscrvr{ions maLle firr sevcn ()lrr of rhc lxst rhifleen ],cars indjcate thet t9l9 n,as the onlv },ilar in which gr.rssJn)ppefsNerc prcs€nr.'they xfc issumed to tre the ori!{raorv gr;Nshoppcr, J..'7gl.?lrrrer melanaplus, rhc m:iJof species ofdre lovdxnLl infeslati()n, ancr ro hevc c(nne tiom a.lrxcenr asriculrurel regionsto thc sourh. Nl(xcmenl \\':tsthroush I seriesof sho( sp()udic flighrs bv smxlt groups or in ciividurls r:rth€f rhin throush missivc millrarion. 'I he molcrrent of lo$'land gresshopp€fs ro high alrirudes provjdcs ioocl for rcsictent animets rnd :r lringe oI pi(rncers lvhich xppl,v Lrps:rrclpressure for cstxbtishment of the specics nr rhe highcsr ahirude possiblc.Their prescncc opens Lrpncw genetic:rnll ecologicxl oppo(unjrics and dennnsrrareslhe essenhelconnectivfv berween nlounlains rnd kr$lan(ls.
Introduction In 1979 the PacificNorihwest cxperienccd one of dtc $.orst grasshopperinlesta tions on rec(xd. High firasshopperpopulations occurred throughout the Colum- bia Plateau,front the baseof the Cascadesto southeast.J(/ashington 'lhe and eastcen tral Idaho. worst stricken arcitswcrc rn norrh centr.rlan,-L n.rrfheast Orcgon where up to J00 grasshopperspcr squaremcter (r.ard)were recordecl(Fillurc l). Thc nlrmber normally considered cxcessiveand {equiring control is eight pcr square meter (yafd) (USDA 19U0).This great grasshoppcr ourbreak epparentl_y resultedfrom a stcady buildup in the popLrlationover severalycars aicled by I,arm sprir.lgtimcconditions, culminatinElin the spring of 1979, which provide cl a per- sistcnt dly s'arming trencl that $,,.?sideel for grasshopper survival (Oregon Agri Record 1979.D.6). Ihis report aiealss,ith a related aspect of th?t infestrtion-thc presencc of grasshoppersat high altitudes in the \X/ellos.aMountains durins the same timc. The \trallo$/as,iocatecl in extreme nurthe.rsteIt Orcg,t11,.1,. fhe highest and most fugged section of the Blue l\{oLrntains.As such they afe ideally siruatedto test the significanccrnd effect of xltitudc on lo$'land grasshopperclistributions sincc the infcstxtion surrour]declthc mountxins on every sicie(Figure t).1
'A jn peculixfitv crisls titc wxy grxssh(4rpcfclensities arc meppcclbv the LrSDA Therc arc rn o .ou.rs (nc rnede:rneoe: isrs ofol nrmphsn\rnphs inln the spring or e;rrlvsunlmer, the othcf is of adults in lete sunmcr or earlr fill. Th€ nymph2l sur\.c! is Lrscdro make decisi(ns to spra!,spray thardrat seas.rnseasarn s.ltcreassltcreas thctlle -r.lrrtrxduh suner.srrri ti jss uscllllusclll lo|ito|i lnahcxtingindlcxting ere,.rsere..isof()1 porentirl problcns tbr the ncxr serson. yrhrle these arc lloth Dflctical xpproachcst() the problcm. the infornati()n aalhercd ?n.l rhe ntxps ther resLrlrlcx\e r jlr!,.1rJr-1 ro be desirecl The n\'mphxl sur!evs arc usuallr not publtshed (or ercn nxppect). Thc mrp shown jn Figure .,I980 I is b:rsc.l(n rhe adLrltsuNet midc in Alrgusr end Scptcmber, I919 (cxlted grasshoppcf ()utkrok .). ll is not I iru€ piclufe of gfesshoppcrclcnsities durnlg 1919, hol1cvcf, sinceir dl)csnor sr)o\\,rhc e.ers Ihat scre spm_!ederrljcf ther sunnlcf (\\'hi(h ivere xlso hexvily infisted rreas).This e\plalns \\.h\, no grasshoppcrs rre sho$,.n on the norih siLl€of the Wall(x\ as, bcreusc rhis lvas onc ot' rhe DrrnciDatsDrrr .re:rsrn l9r9 As a gcographerintcfcsred in rhr coltecrionanll mappjng of clata.lfrnLl ltr\.ltrnr|rLh flr from s:rtisf2ctofl Nvnlphal suf\ eys rnLl spfa,v ere:ts should also be inclLlded to shoB-.a mofc co't plete picrure of grasshoppefdcnsities (hrfing a given lcxf.
NorthwestScience, Voi. 59, No. 3, 1985 21J 3 lo 7 grasshoppers p€r square yard
8 or |nors grasshopp6rs per square yerd
Fi!!ufc1. A.luhgfasshopper densjties in thc PaciflcNofthwesr during late sunlmcf and fxil. 197t)(See Foomorel) (LJSDA,1980).
StudyArea The lfallowas are a circular domc shapedarea approximately 60 km in diameter rising to ?n eler.atecicorc of 3,000 m. They are comprised of sedirnentarvand volcanic rocks overlYinge granitic batholith \\'hiclt hasbcen exposedat thc center b.vst.ong:il:icial efosion (Smith anclAllen 19,11).Glacial \.alleysracliarc ourwafd in all directiorrsard ar the hub is La5;1cC.ap,2,925 lL high. On rhe north side of EaE{leC?p is tlre Lakc Basin.a broaclclccp Valley$'itlt str()ngice scoured surfaces and paternosterlakes. This is the hcart of the EagleCap \WiiderltessArea and the fbcus of tl)is sruclv (Figul.e2). Thc W2llo$'ashavc a continental climatic rcgime s,'itha summcr pfecipitation maxima. Enterprisc, located il-nntealiatcllto the north of thc range, lcccivcs tn avere€lealrlrual prccipiterion of 3.15mm (NOA-A.1980). Thc mountainsrerei! e con- siderabh.more than this, of coursc, from borh summer thunderstormsand winter 'lhe snow. W2llo$.:rs are surroullaled bl. semiarid stellpe, !i,'hich uncler.natur:rlcon ditions, slrpport buncligr:rss (Agropyron spic.rtutn, Festucq idaboensis) a]nd sirgcbrush (Artelnisia trident.tt.t). Ponclcrosa pine (Pinus f)oltdero.sa) be€lins at about 900 n grilding uix'arcl into Douglxs fir (Pseudotsug.t tnenziesii) anal Grand,
2lq Price Porlland t aGrand€. Bs|(6r
Figurc 2. I-oc:rti(nr and ropoliraphy ()f Lake Basin wirhin Eagle cip v .lcrn€ss. !frrolvr Nfounrxirs. Dol partcrn derbtcs m;lin afcis ofgrasshopperoccurrcnce Bascmrp is Il S.c.S. Ergle C:lp 15 Quactrilngle, orinlrtc series.Conbur inrervel ts 2i.1 nl (80 ft ) xnd ho'zonul clistince acrossmrp js .i.5 km (2.8 nilcs) fir (Abiesgrdndis). Thc Subalpinezone beginser 2,100 m consisringoisubelpinc (Abies tir lasiocdp.t), Whitebark pine (piluts .ttbic.tl is), ancl Engelmann Spruce (Picee engelnctnni). lt is clitficult to cstablish an altitucle tbr the upller timberline \Wallo\\'as in the because rtf thc prevalcnce of bare rock surfaces.which is as much a limifing fact()r as is altituclc. Trees gro$, cntirely to thc tops of thc peeks in favorable sites and would Elohighcr if rhe mount2il.rswcre lti€lher(price t 9B,i). Subalpine meaclou's occur. tlrroughout the uppef rcaches of thc Wallo$.as, hou,ever, and a well alevelopeda$inc flora cxists (Mason 1975). For scven out of thc last thirteeD ,vearsI have spcnt onc week to tcn cuvs rn earl)'July campecl in rlte rLppe. L:rke Basin $,ith sludents tiom the geograph,vsum poftland lner fielclcamp at StateUniversity. This hasgiven mc amplc oppoitunitl, to oDservcconditions there on a continuing basis.The Lake Basin is J knl $,idc b,v6 km long oriented northcast,southwestrvith valley flOor elev:rrronsr.angrng irom 2,100 to 2,J00 ln (Figure2). The basin headsin a largeamphithearer beloq, -fhe Eagle Cap $ here it is fimmeal by steep heedwalls on the south ancl $,est. preyailing sourhwesteriv I'ind aluring $,inter swceps snox,- off the surrounding ridgesand deposirsit in dre Lakellasin. Corrsequentlv, the Nlirrof Lakr sLrt,r \urver Stationlocatecl in the brsin inrmediatcly belo*, EagicCap at 2,500 m rec(x.ls one ofthe hea\.iestsnow acculruletions in C)regon.On May l, 1979, there was,i.4,15 cm ot snow grounci, on the which is about averagefor this rine of ).ear(t,.S. Dept.
Grasshoppcrson Snox' 215 Agri. 1979). Stormy weatheer typicall). continues into NIey and June and main tains a thick snow covcr in the uppcr Lake Basin until e:uly.July I'hen lake ice is tust be€tinningto nclt (Price I984). This, then, is the setlinElin which the follo$' ing obscrvations wcre naclc.
Melhods
Grassi]oppersn'ere Iirsl observcd on Julv 6 oD the sr.lowin the lee of E2gleCap ftom abolrt 2.,i50 n.rupr":rrcls. l his rvasearly molning and the snow was still fiozcn. The grasshoppersn'ere letl.t:rrgicand scarcelymoving. When we picked them up the,v rcmainccl motionless. Bv afternoon. however, thc sn(x'\,':rs soft anclslusitv and man,vof thc grasshopperswerc active and occasionallyhoppcd across the snovi'.They coulcl stilI be easily caught but novu'if you opened yolrr hand thcv 'l would jr,rr.r.rpout. he grasshopperswere typicallv Iocated in sull cups in thc snow and s,'ereoften sunken into small r'crtical depressions becauseof their darker color ancl greater absorptivity. Alnost all wcre alive on this active snow surface indic2tin[l that rhev had not been thcrc long. There was no food ot.rthe snow fbr them to eat so presumablv most rvould die wjthin a few days. Sevelal small birds wcrc observed harvesting the grasshoppersas s'ell as other insects on the snow. Unlike the nofth'facing slope. where blo*'ovcr sno\{ accurrulatesaltd tlte shadow clin-iateprotects it lrom melting, the bro2d and gcntlc south sloping sum mit of EagleCap at 2,925 m is norNally snow-free by earh.July(as it was in 1979). Scatteredclunlps of shrubby \vhitebark pine grow up lo 1 m high on the sunmit but rrost of rhc surf'accis a windswept fell field supportil.I€lsparse alpinc mat ancl clrshion plants (Pricc 1984). A svstematic search of rhc upper summit onJuly 6 revealed only three grasshop pers. In contrast \,'ith those on the snow, thcsc were extremely active and dif- ficLrlttO catch. Tbe $'eather on this clal.was sunn,viletwecn thc c(:)nvectionalclouds and occasionalsbop'els so the soil surfacewas \n'arm.1hc wind \vas s()uthwest erly ?t 15 J0 km per hour. I triecl to cetch one of thc grasshoppersancl it quickly jumped witl.rthe r.incl to a height of abouf I m anclwas whjskeclover the summit hcadn a11,presurrabl,v to land on the snow somc 300 400 m belo\\'. No evidence oinibbling on thc plants or any other evidenceofdamage fi'om grasshoppcrswas observed. The ncxt day I fcvisiteclthe snos'fie1dand began more systemxtics.rmpling. On the 1.i km hike liom ,\4occasiDLake to Mirror Lake I saw only two grasshop pers alon€lthc trail bnt once above Mirro. Lake on the snow they bccamc morc commor (!'igure 2). Bv 2,,i50 m the density of grasshoppersincrcascd to 1 per 10 m in a $,alking transectup the slope covering a s\\'ath6 n wicle. B,v2,50t) m, analclose to rhe north facing hcad\1,allof EagleCap, the clensity\\.?s greatest- about I grasshopperevery 2 m in a swath 6 m v,ide (a five fold increase).C)nce aft)p the broad s"'indsn'eptriclge. howcvcf, only occ:rsionalgfasshoppers were sighted. At the s.u.netime the students rvorking on various projects throughout the Lakc Ihsin. ol)served ciccasionalgrasshc)ppers around Moccasin Lake,Nlirror Lake, and the upper Lostine Vallcy. None w;rs seen in the Lower Lake ts:rsin although flve peogrlervere dorvn there $'ith instructions to look. Clearlv, grasshop pcrs r.crc most :rbundant on the snow to thc immcdiatc lee of Eagle Cap (Figure 2).
215 Priee Resultsand Discussion Ail of the grasshcppers were aclults *,ith wcll devcloped $,i1.r1js.Screral specimcns s'cre coilected for identitication but \,'erc lost. f'hey arc, nevertheless,:rssumcd to be the migrarory grasshopper, IIeldnoplus s.tngltinipes. Ihe alolninJar reprcscr_ tative of the lowlanci infcsr?tion (Coealen 1979). Anothcr spccr.s.trIelan()plus alpitius. lrves natLrrallvup into the subalpine zone Ol the \fallowas tlut rt ts :r somex'hat stllaller cre:ltufc comp:rrec1to thc lar.gerYelio$, and rcclcljshbfon n gresshoppersI observecl.lhe obscn.ationelperiod $,ascarl_yJul,v ?nd far too c:uly fol the appearance of ,11e/anoplus.ttplzr,rs. vi,hich clocs not norlnally mature rLntil micl-August(Banfill :rnd Brusven l97j). lnterestin€lly, while most los,lancl grasshop- pcrs corrplcre thcir life c\cles in one ,vcar,rhis highjand specicsmav teke three ycars for complerc development (Kr.easky1960). A iln al infe|encc is t hat I 9 f9 \r'esth e only veer out Of the tirllor.i ng sccluclcc of 1-ears 1970. :-1,13.11,78,79. 8j thar gfasshoppcrswerc obserYedon snox,. ..aeolian in thc W?llowas. I ha!,e lonli been intrigued b,v thc zonc,, and rctiveiv searchtbf arthropoclson alpine snow. Conscqltentlv, I can sa\.$ rth (unliLlrncc that this \\'as the onl,v ,veafctf the ser cn that €arassltoppers\\,.cre prcseltt olt sno\v et the time I was therc in earlvJLrl\'. The implicatiuts :rreclcar.; thcir 1trcscnccin 1979 secns to bc felated to thcir great rbunciancein the surrolrlrclinglowlancls. "\\'hlt The quesrioll that now arjscs iri: $rcre the grasstroppers " cloiltg at this altitucle? The prescnce of lo\,lancl grasshoppersat high elritudcs is not particuiarlv c)64) unique.Alexander ( 195 1. 1 reports that lowlancl€lrasshoppers can be observecl on alpirle sno\\' in the Floltt Rangc of the Colorado Rockies almosr ever\. slUl.l mer, cspeciallv\,-hcre the Dountain are:l cxtenalsclose t
Grasshopperson Snow 21j Resultsand Discussion All of the grasshopperswere adults with well developecl wings. Several spccimens were collecteclfor identit'ication but were Iost. They are, n!verthcless, assumed to be rhe migrarorv grasshopper, Mela noplus s.tngui;ipes, the cilminanr represen tarive of rhe lowlancl ir.rfcstarion.(coeclen f llij. motner sptectes,uetanoplus ctlpinus, Iives natur2ly up into tr.rc subalpine zone of the \faltowas but it is a sontewl.rat smalier creature comparecl to the larger 'fhc yello.l, a.rct rccidish brown grasshoppersI observecl. observatlonai periocl wai earlyJuly and ier too early forthe appearancc of Meran(r)rus arplzuaz.E which cloesnot normallv mature untii mid-Augusr (B2nfill and Brusycn 197J). Interesringly, s,hile mosr lowland grasshop pers complete ri'tcirlife cyclcs in one yca., this highland speciesmav take years threc for complete development (ttueasky1960). A fit.r:rlinfcrence is that I979 was the only )ica. out of the follu!\,.lngscqucncc ot years 1970,71,73,74,78,79, 83_thar gr:r^sshoppcrswerc observecior.r sno\. in the \ allowas. I have long ,,aeolian been intriguccl bv the zone,,?nd acuvely searchfor arthropods on alpirc snow. Consequentl),,I can sal. with confidence that tilis was the axtl)' of \,car the seven that grasshoppers *ara prarar], oi_tsuow I w:rs there in ealll.luly. 1'^:1t'i-. the impiications "...r."r; iheir prcsencein 1979 seemsto be related to their great abundancein the surroundng lo$.lanals. The quesrion that now arises ,.\fhat is: were the grrrrn,,fp.^ doing at altitude?" this The presence of lo\4and farasshoppers at hiElh alrjtudes is not particularl], unique.Alexar.rcler (1951, 1964) reforts that lor4anl grasshopperscan Deobscrved on alpinc snow in the Front Rrngc of the Color.adoRockies alnrosreyery sum_ mer, especiallyq,l]cre the mountain area extends close to or is surrounalealby lowlands. This annual visirarion bv grasshopperci, "..o_ptiJJ plmarily by in diviclual straggrersor groups of stragglers which have flown or h:rve been c?rried there by the wind. rWeather conditiomsin continental 1r]ountainsarc idcal durinfl summer lor Llp q'ard movemcnt of insectssince the air.typlcallv movcs upslopc cluring the da), and clown at'ight. Grasshoppers woulcl only bc acti'e a.iing tne dav since lo\r, nl€lhttempe[aturcs would rendcr them inactive. This corrclatcsnrcelv with Alex, ?ndcr's obscryations in the Rockies ,,I when he statcs have nevcr rellno a nlon, tanc grasshoppcrmore than :rfew hundred leet bclo$, its ltormal altitudinal range but have collectecl rnany specicsup " to sevcrai thousanclfeer above nomal brecdinll ranEle. (Alcxander 196,1).Grasshoppcrs that occur at hiEIhalritudes bevoncl their normal resiclcntrange:rre termed,,accideDtals.,,lccidcniats do not comptete their cyclc in the ahine zone and usuall),2rrive asadults betbre aclultsrcsldent at highcr altitudes coLrld-have matured (Alexander 1964). Of course, evcn resitlent alpine speciessrculd be "accident?ls,'()n thc snos, sinceit is obviousll,arr allcn enytron ment to all grasshoppers. Muclt morc iD.rpressive than inclivicjLlal movenlcltt is the massive migrations ir.twhich some €a.assrroppcrsinclulge ancl which *orlld not be rimitcd to marginal ranges.These have been fantous ,,the since biblical times when face of the wh(re land_.. r,'as ciarkened,,(Exoclus perhaps l0:l5). the nost notabie example grasshoppcrs js of in mountains on Grasshopper Glicier in northeastern yello\\,stonc National PZrk,I,lontan:1. Herc thousands of grassl]oppcrsare encaseclin lavers or.
Grasshopperson Snow 217 bands in tbe ice atld are releaseclbv mclting each sumlllcr to be eaten bv birds and fish or sirrply carriecl:rwa.v in tlte $'2ter (Gurncy 1952).Although some ?re estimatedto havc been in the icc 300 400 years,othcrs continue to accunlulate. ln 1949, for examplc, numcrolrs individuals of f,lelanaPlus /lg.g/€r.sl$'crc fotncl on the sllo\\'field of thc €llaciers.This spcciesis found prilraril-Yin southeastern OreElon?nd lorthcrn Nevada ?nd is assut.nedto have nigrated ?]l rhrr distance fGLuncv 1952 ). The causcsof rnassivegrassht)ppef migrations arc unkno\vn. Possibleexplena- tions includcr searchfbr fbod, cscapefrom ovelcrctwciingor uncomf()rtalllesur rounciir.rgs,ol sinrplv a respor.rseto thc herding instinct (Hantsbafger 1979). Typical- ly the mjgration begins by indivialualsmilling about or fl)'ing short distanccsdur ing the hottcst time of the c1a,v.This excites olhcrs :lnd thev begin to fly, but still as incliviclualsand in no particuiar direction. Then, inscrutablv, one day the g|asshOppcrsswa|n and ire€iintl)'ing enmassefor parts utrknown. T hcy no\\' act as a unit ar.rcllbllow the leacler$'ithout hesitation. Swarms fl1' onll when conditions arc travrtrable whcn it is warm 2ncl cicar with light s,-incl.Some gfasshoppersflv againstthe $'ind or diagonallv to il, but tlre migrator!'grasshopper, Melanaplus sanguinil)es, rises aElainstthe s'ind rnd then turns anclliies aio$.nwind. Rising:rir curlents duritg the hot ti1neof the da]' helps the insect gain altitudc and flying with the \r'iltalinclcascs its travel specd, \,'hich is nornallv about t arkm pcr hour. The Migratorv grasshopper is known to movc dist:rncesof 10 to B0 km per d2) and over 800 knl in a sexson(H1llls barger 1979). The presence ol grasshopperson alpine snow and €ilacicrsis at- tributcd to unstrblc mount:rin weather. The swan-]tsapptrcntl,Y lalld imlnediatcly if thc sk-vc|ruds or if tcnperatules drop. Therefore, if ckruds or ston.nsdcvclop while grasshoppersare passingover the mountains, the-vallrickly dr()p otlto the surface wirich, if sno\\r, reifjger?tes lhcn and they die within a few days. 'Ihc exact method oi grasshoppermovemcnt to:rlPine snow in the \vallow?s during 1979 is nnkno$,r.t.Their c()ncentr:rtionin ollc areato the lee of EaE]lcCap argucsin favor of a singlc event, e.g..migriltion, llut their limitccl numbers of only a few hundred favoLsmovctlent on a lesserscale. There were also no rcports of sw?fming trom local r:rnchers (x frorr spray pilots (pcrsonal comn-runication, Ken Goeden. entomologist. Orcgam Departmcnt of Agriculture). Pcrhaps the most likelv explanationis movement throLrghi seriesof short sporaclicflights by smallgroups ofincliviclualsrather than nassive migration. In this regard,the p?ttcrn offadiating glacial vallcys in the Wallon'as ntay havc aideclgrasshopper moYement. Thesc broacl and cleepvallcys provide greater claytime he2tin€;,rvcll clevelopedup v2lley breezes, and a chlnncling efTectto\\'rrd Eagle Cap. That grasshoppefscan rerllain activc ar higher altitucles,and therefore 2rccomplishthe trip over scYerxlsegments, is demonstratcclb-v the vigor ol thcir movemetrtsobscrved under sulnv conditions on the snow-fice sunl]rit of Eagle Cap on Jul,v6. The V/allo$'as,Iike the F'rollt Rallgein Cok)raalo.are verY acccssibleto the surrounalinglo$'lands, being only 20 30 km a\\'al', anci ilnnual visitation b'' inclividual grasshoppcrswoulcl seem likeh' to occur, althougll it has not been alocun-tentedto my knowledge. Circtlnstances in 1979 wcre unusu2l,howcvcr, and resulted in Eireaternumbers ofgrasshopPers at higher altito(ics than normal, cspecially those on sn()w. The grasshoppcrsare thought to have come prinaril)' irom the agricultural are:rsto the south side of lhc Wallos'as,e.g., thc GrancleRoncle or ts:rkcrValle,vs.
218 Price This is basedon the fact that the winal hacl been preclominantly south southwesterly for thc previous fce/ days. The plateau'sweather had been unstable with con- siderableconvection activity. Daytill]e temperaturesreached 30" C onJuly l, 4, 5, 6 at both Baker and Lacranclealttrough a trace of precipitation was recorded on each of these days (NOAA 1979). Gr?sshopperclensitics in these areaswere also above averagereaching 40 to 50 per square m (vard) (unpublishecrsurvey oara, Oregon Department of Agriculture). Bv contrast, agriculturalareas to the north \X/allon'as of the u'cre spravedin earlyJuly, 1979.The primary pesricideusecl was malthion which accomplishesalmost complere kill within onc day anclgrasshop pers usuailv do not tly afier being sprayecl(personal communicatiorl, Ken Goecjen, cntomologist, Oregon Department of A€lficulture). Halching on fhe plateau normall,v occurs from March or April onwarals so there is generallyample timc fbr development inro adulrswirh full wings bv carlyJuly. Hatch times are extrer.r.rel,vveri?ble, however, depenclinglon altitude and other environmentalfactors (l{andfbral 1961).For example, ltatch times ll-ereup to six $'eeksearlier in the Intltahr Caltyon anclIlaker V?lley as opposeclto areasar()unal Enterpriseolr thc north siclcof tlte Wailo$'aswhere grasshopperswere obserr.ecl still in the n].mphel stageon.lull..1, 1979 (pers. con]m., Rick WescotL,enro[toroglsr, Oregon Department of Agriculturc). This was the samc time I },as observing full adults on snow in thc high \(/ailowas. \Xlhat is the significtnce of lowlancl p;rasshoppermovement to highcr altituales? On an ccological basis tltey scrve as fcrod for bircls, insects, fish, and other animals. Their presence also provicles cvidence of processesancl events going on in the bw lands I'hich occasionally extend into the mountains. In the $fallowas. Lrnswas cs peciallv cvident in 1979 whcn the greater grasshopper abundance in the iox4ancls was expressed bl gr-eaternumbers in the highlands. The prcsence Of lon land grass- hoppers at higher altitudes is reflcctive of the gelteral trencl for insecrs ro move or "acciclentals" fo be carried bodily upslope in mounrains. Such constitute a fringe of pioneers rcacly to establish the species at the highest eltitualespossible fcrr survival rn an)'givcn season.D?vtilne temper.rturesin mountains are high cnough tbr los,iand grasshoppcrs to be acti\-e so that esis and young wouid be available in Ltosr I c.us above shcre the species normally reaches maturity. Consequently, there is ? cons tant upward pressure for estxbiishment at higher cleyetioDs (Alexancler 1964). In aclditiarlto providing tiesh gcnetic and ccologicalopportuniLresJ rne move- lllenr of organisms:rcross altitudinxl gradientsdentonstrates tlte cssentialconnec tivit,v of high and low aitiruales.While mountains exist as environmental 2nc1 "islands" ecoiogical :rnidst surrounding lo$'land se:rs,and interchangeis iimitecl, it ncve|thelessoccurs. f he identification of the parltwaysancj processes involvecl in this interchenge is ccntr:ll to understanding of the mountain ecosystcm.TIle movement of lowland grasshoppers:rnd other arthropoclsto high elev?tions is a small, but important, part of that picture.
Acknowledgments \Wescotr Rick and Kcnnerlt Gocden, Orefion Departnent of Allriculture, supplieclmc with unpublished data and answered rny nlanv qucdes. NT.A. Ilrusven, Llni\.ersity of Iclaho s.as also rnosr helpfll. Lasrly, I rhank rhe stu.lcnrs of the 1979 geographl. sunmer field camp, Portland Srete Llniversitv. for their ideas end ODservattons.
Grasshopperson Snoy' 219 LiteratureCited
Alexander, Gordon. 1951. The occurrence of Orrhoprerx at high alritudes, with special reference to Colorado Acrididae. Ecol. 32: 104-112. -. 1964. Occ rrence of grasshoppers as accidentals in the Rocky Mountains of Norrhern Col oraoo. rcot. {). //-tto. Banfill, John C., and M. A. Brusven. 1973. Food habits and ecology of grasshoppers in rhe Seven Devils Mountains and Salmon River breaks of ldaho. Melanderia 12: 1-21. Goeden, Kenneth. 1979. Summary of 1979 Oregon adult gmsshopper and Morman cricker surveys. Unpublished lefter to Da\.id Keim, Sta(eDepaftment ofAgriculture, Sa1em,Oregon, September 26. 1979. Gurney, Ashley B. 1952. Grasshopper glacier of Montana and its relation to long disrxnce flighrs of grasshoppers. Smiths. Inst., Ann. Rept., Pobl. 4lll, 307-327. Handford, R. H. 1961. Developmentel patterns of clearwinged grasshopper ar different altirudes and in differenr years on a sheep range in British Columbia, Canada. Can. Ent. 93: 655 670. Hantsbarger, William M. 1979. Grasshoppers in Colorado. Coop. Exr. Ser., Colorado Stare Univ., Fort Collins. Bull. 502A. Kreasky, J. B. 1960. Extended diapause in eggs of high altirude species of grasshoppers, and a nore on foodplant preferences of Melanoplus bruneri. A.nn. Ent. Soc. Am€r. 53: 436 438. Mason, Georgia. 1975- Gujde to the Planrs of rhe Wallowa Mountains of Norrheastern Oregoo- Spec. Pub; Museutu Natural History, Universiry of Oregon, Eugene. NOAA. 1979. Climatological Data, OregonJuly, 1979. Nat. Oceanic Atmosph. Admin. Nat. Climxtic Cen., Asheville,N. C. Vol.85, no. 7. -. 1980. Climatological Data, Anmral Summary, Oregon. Nar. Oceanic Atmosph. Admin. Nar. Climatic Cen., dsheville, Nortb Carolioa. Vol. 86, no. 13. Oregon Agd Recorcl. 1979- Grasshopper plague a war of a different kind. Oregon Agri,Record no. 280, 3 6. Price, L. \y,/. 1984. Ecological inversion in the Wallowa Mounrains, O.egon. Paper presenred ar 25th Int. Geog. Cong. Paris, France, Aug.27'31. Smith, w. D., and]. E. Allen. 1941. Geology and physiography of the nofthern Wallowa Mountains, . Oregon. Oregon Dept. Geol. and Mineral Ind. Bull. 12. USDA. 1979. Record ofsnow data measuremeors, Mirrot Lake, aerial marker. U. S_Depr. ofAgri., Soil Cons. Ser., Pordand, Oregon. -. 1980. 1980 grasshopper outlook. Animal and plam healrh inspection service, cPO 1980 697-411. Receiued 11 April 1984 Accepted for publication 19 July 1984
220 Price