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are digestingtheir green mealstakenduring the previous night,and being po'.d_ilotherms, i.e.cold-blooded,they m __body ternperatures byhuddling in thesun, and therebyaccelerating_ growth, Htmkeringtogetherin .l,grgegroups_y _ eonf_ pr0_-tion against some kinds ofnatural enemies,alflaoughvery few birds Willeatthem! Near the endof June,upon reachingsatiation,flaenow grown cat,rpillarsprepare forthe pupal stageby wandering about in searchof a suitablesit_for coeooning.Ifthere are leavesleftanywhere in the forest, thecaterpillarscommonlytieseveraltogetherwith silk:andthen inside spin a 2-inch.long,yeUowish-silken _ aboutthemselves.Theymetamorpose intoa dark satinbrown pupa. Males typicallyemergefirstand waitfor thefemalestoarrive, Females,bearingtheburdenofabouttwo hundredeggs,aretypically twiceas largeas the agilemales.Afterbeing _, the _es _ dumptheirentirecargoin onestop.Theeggsaredepositedin aminia- tureroot-beerbarrelmass,whichfullysurroundthesmalldJameter twigsin thecanopiesof aspens.Typicallytheeggsaremostcommonin tophalfofthetrees.Onecaneasilysee themwitha pairof binoculars Wh_ the.treeis leaflessagainsta dear sky. A few weeksaftereggsarelaid,aboutAugust1,the egg _orphosesintoavery tinylarva.Thelarvaremainsquiescent,andstartto

prepare physiologicallyfc Staff: VMPR Problem: 1 insidethe eggshell whet( Code: 1.21 Reprints: Yes weatherhigh up in the tn February,dip below-40E. _----_,--o ---populationsto nearcollapse.Barringsuch seriouscoldsnaps,the eggbound larvae are eventuallytriggeredinto activityas warm spring weatherarrives. As a rule ofthumb,caterpillarsbore through the egg shellsduring earlyMay.Becauseall theeggsfrom eachfemalesare laid in a single mass,theyoung larvaefrom eachtypicallyhang _ movingtoand frofrom egg mass tobranchtips forfeedingas a familyunit.Silken tracksarelaiddown as they move fromplacetoplace and thisphysical trackalongwitha chemicalscentmarkeralsolaiddown,permitthe groups tomove effidentlytogether With a_ caseofwanderlust,somecat,pillars refuseto stay put.Theyforsakethethe motiaertree andstartaninsatiablesearr.hfor greenerpastures.Ithasbeenhypo_ thatthep_ eat_nleaves oftreesreleasechemicalcuesthatattractparasitesandpreda_rsofthe tentcaterpillars.Andso perhapsthe bentca_rpillarsthatwe seeinnear pe_,tual, motionare_ fugitives,forevermovingtDkeeponestep aheadoftheirpersecutors.

_fferlFORESTS .

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Thefront .coverphotos are by nature . photographer,Scott Sharkey. The back

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PJh°t°wastakenbyMim' Barzen, Capturingthemomentwhen her daughter first tasted the sweet sapofspring'smaplesugarrun, ,.

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