Reproductive Timing and Reliance on Hoarded Capital Resources by Lactating Red

Reproductive timing and reliance on hoarded capital resources by lactating red squirrels.Oecologia.QuinnE.Fletcher*,ManuelleLandry-Cuerrier,StanBoutin,AndrewG.McAdam,JohnR.Speakman,andMurrayM.Humphries

*InstituteofBiologicalandEnvironmentalSciences,UniversityofAberdeen,AberdeenAB242TZ,UK;

TableS1.Descending-orderedtallyofthenumberoftimesredsquirrelswereobservedfeedingonthesevencategoriesoffooditems.Feedingobservationswerecollectedfrom1990 – 2010(excluding1998;seemaintext).Thelactationperiodforthispopulationis~70daysandwedefinedthemid-lactationperiodbetween20and50dayspostpartum. Caution must be exercised when evaluating the counts from non-lactating females because they include some feeding events from lactating females. The reason for this is that we excluded inaccurate parturition date estimates from our data set, and thus feeding events from lactating females with these inaccurate parturition date estimates are listed with the non-lactating female feeding events. “Whitesprucebuds” includesfeedingonbothundifferentiatedanddifferentiatedreproductiveandvegetativePiceaglaucabuds.Thecategories “Hoardedcones” and “Freshcones” refertofeedingobservationsonwhitespruceseedsfromconesthatwerehoardedinpreviousyears,orcamefromconesproducedinthecurrentyear,respectively.Squirrelswerealsoobservedfeedingonmushrooms(poolingepigeousandhypogeousmushrooms).Inthefield,wedidnotdifferentiatebetweenfeedingeventsonmushroomsthatwerehoardedinpreviousyears(Hoardedmushrooms),orfeedingeventsonmushroomsthatwereproducedinthecurrentyear(Freshmushrooms);however,weassignedall2811feedingobservationsonmushrooms(858Hoarded+1953Fresh)basedonthetransitionbetweenthesetwotypesofmushroomsinasubsetoffeedingobservationsin2009whenfreshandhoardedmushroomswererecordedasseparateitems(seeFig.S1). “Witch'sbroom” referstofeedingobservationsonwhitesprucewitch'sbroomrustcausedbythefungusChrysomyxaarctostaphyli.Withinthe “Other” category,thetypeof “Animalmaterial” wasnotrecordedinallinstancesofthissub-category,butwhenindicated,itprimarilyconsistedofsquirrelsgnawingonbones,butitalsoincludedpredationeventsononered-backedvole(Myodesrutilus),unspecifiedbirds(n=2),andsnowshoehares(Lepusamericanus;oneadultandoneleveret).Weomitted385feedingobservationson “bark” becausethetreespecieswasnotrecordedinallcases(willow[Salixspp.]orwhitesprucewerebothrecorded),anditispossiblethatthosefeedingobservationsonbarkwithanunspecifiedspecies,andonwhitesprucebark,wereactuallyfeedingobservationsonsprucebarkbeetlelarvae(Dendroctonusrufipennis)livingunderwhitesprucebark(Pretzlawetal.2006).ThespeciesnameforbearberryisArctostaphylosuva-ursi.

Referencescitedonlyforthissupplementarytable

PretzlawT,TrudeauC,HumphriesMM,LaMontagneJM,BoutinS(2006)Redsquirrels(Tamiasciurushudsonicus)feedingonsprucebarkbeetles(Dendroctonusrufipennis):energeticandecologicalimplications.JMammal87:909-914.

FigureS1.Asubsetoffeedingeventsonmushroomsin2009,whenfreshandhoardedmushroomswererecordedasseparateitems(n=195,18March – 13August).Eachpointrepresentsamushroomfeedingeventonagivenday.Thelineofbestfitisfromatwo-parameterlogisticfunctionmodelwithhoardedmushrooms=0andfreshmushrooms=1asthedependentvariable,anddays since 1 January as the independent variable (two parameter logistic: ea+bx / 1 + ea+bx; a = -21.7 ± 3.4 [SE], z = -6.4, P < 0.0001; b = 0.12 ± 0.02, z = 6.6, P < 0.0001).Thislineofbestfitreflectstheproportionofmushroomfeedingeventsonagivendayin2009thatwereonfreshmushrooms.Thisproportionwasusedasathresholdvaluetoassignthemushroomfeedingeventsinallstudyyearstobeeitheronhoardedorfreshmushrooms.Specifically,ifarandomnumbergeneratedforeachmushroomfeedingeventinallstudyyearswaslessthan,orgreaterthanorequaltothisthreshold,themushroomfeedingeventwasassignedtobeeitherafreshorhoardedmushroomfeedingevent,respectively.