Table Of ContentJournalofResearchontheLepidoptera 29(3):173-194, 1990(91)
Evolutionary Ecology ofSympatric Catocala Moths
(Lepidoptera: Noctuidae)
Experiments on Larval Foodplant Specificity
I.
Lawrence F. Gall
EntomologyDivision,PeabodyMuseumofNaturalHistory,YaleUniversity,NewHaven,
CT06511USA
Abstract. Larvalfoodplantspecificitiesarepresentedfor31speciesof
Nearctic Catocala moths whose larvae feed on trees in the plant
families Juglandaceae, Fagaceae, and Salicaceae. Arena tests deter-
mined preferences when larvae could choose on which plants to feed,
andfieldrearingexperimentsdeterminedsurvivalandgrowthratesin
no-choicesituations. Inarenas,larvaeoftheJuglandaceae,Fagaceae
and Salicaceae feeders ate only foods from their own plant family.
Taxonomic divisions within each plant family definedfurtherbound-
aries to foodplant acceptability. Thus, amongthe Juglandaceae feed-
ers,2speciesatewalnuts(Juglans),2atepecans(section§Apocaryaof
Carya), and the remaining 14 ate hickories sensu strictu (section
§EucaryaofCarya). AlltheCarya section§Eucaryafeederspreferred
shagbarkhickory, Carya ovata and 6 ofthe 14 species specialized on
,
it. AmongtheSalicaceaefeeders, 1speciesatewillows(Salix)and6ate
poplars (Populus), Foodplant preferences were not crisply defined in
the5Fagaceaefeeders. Larvaeusuallyselectedthefavoredfoodplant
as a resting site. Preferences broadened as larvae matured, and the
Juglandaceae and Salicaceae feeders preferredyoungleaves over old
leaves. Innearlyallcases,survivalwashighestandgrowthratesmost
rapidin the field onthe foodplants preferred in arenatests.
Introduction
TheHolarcticnoctuidmothgenus Catocala Schrankcontains slightly
over 200 species, distributed equally across the Nearctic and Palearctic
temperate zones. The genus is most atypical for noctuids in showing
great species diversity coupled with highly restricted larval foodplant
—
use larvaeofindividualCatocalaspecieseatonlyoneorseveralclosely
related plant genera, and the recorded foodplant breadth ofthe genus
spans but nine dicotyledonous plant families. Even this liberally esti-
matesfoodplantbreadthamongCatocala,as137ofthe161specieswhose
life histories are currently known feed only on plants in the families
Juglandaceae,Fagaceae,Salicaceae,orRosaceae,Therearelargearrays
ofsympatric, synchronic, closelyrelated species feedingineachofthese
fourplantfamilies, andhence the Catocala are well suitedfor studying
thephylogenetichistoryoffoodplantexploitation(notethatthereported
high species diversity is not in question, since survey collecting for the
moths and the species-level taxonomy of the genus have been amply
studied: see Hampson, 1912; Barnes & McBunnough, 1918; Forbes,
1954; Sargent, 1976, 1977).
174 J. Res. Lepid.
Thisisthefirstofthreebaselinedatapapersaddressingthefoodplant-
linked ecologies of Catocala moths, and covers experiments on larval
foodplantspecificityof31NearcticCatocalaspecieswhoselarvaefeedon
Juglandaceae, Fagaceae, Salicaceae, and Rosaceae. The following two
articlesinthisjournalissueexamine distributions ofwildlarvae among
their foodplants and the oviposition preferences ofthe female moths; a
relatedpaperhascoveredlarvalfeedinghabitswithinindividualfoodplant
trees(Gall, 1987). Thedatainthesearticleshelpcircumscribethelimits
ofpotentialfoodplantacceptabilityforthemajorgroupsofCatocala, and
form the backdrop against which questions about foodplant use in
ecological and evolutionary time by the same Catocala species can be
appropriately framed.
Because analysisofthe phylogenetichistoryofCatocala foodplantuse
is made easier by simultaneously comparing results from all these
studies, I have extractedparts ofwhatwouldtraditionallycomprise the
Discussion sections from the three articles in this series, and will be
integratingtheseintoacomparativetreatiseonthesubject. Towardthat
same goal, a separate series ofconcurrent articles is addressing taxo-
nomic and nomenclatural issues in the genus (see Gall & Hawks, 1990;
our taxonomic monograph ofall the Nearctic Catocala species is also in
the late stages ofpreparation, to be published in a forthcoming “Moths
ofNorth America North ofMexico” fascicle).
Materials and Methods
A BIOLOGICAL PROFILE OF CATOCALA
All Catocala are univoltine, with adults flying in mid to late summer and
hibernal diapause as eggs. The adults have cryptic forewings which conceal
boldlypatternedhindwings; theinteractions ofthe adultswithavianpredators
havebeenthetopicofmanypreviousstudiesbySargentandhiscoworkers(e.g.,
Sargent, 1976, 1977; Schlenoff, 1985). Eggs are laid singly or in clumps under
exfoliating bark, or in crevices on tree trunks and branches. In northeastern
NorthAmerica,mostspeciescommencefeedingaslarvaeduringMay.Egghatch
can be synchronous or highly staggered, but is constant,within any given
Catocala species, the degree ofstaggering being closely linked to the foliating
schedules ofthe different larval foodplants (Schweitzer, 1982; Schweitzer and
Gall, in preparation).
The larvae are semiloopers, usually with highly cryptic morphologies that
.
matchthetwigsandbarkwhichserveasrestingsitesduringthedaytime. Larvae
generallyfeedatnight. Priortothisresearch,thewildlarvaehadbeenpresumed
to be mildly oligophagous among related plant genera within single plant
families. Foodplantbreakdowns forthe 108 Nearctic species which I currently
plan to recognize in the forthcoming taxonomic monograph are as follows:
Fagacaeae,26;Juglandaceae,25;Salicaceae,23;Rosaceae, 15;Leguminoseae,7;
Ericaceae,4;Myricaceae,4;Tiliaceae, 1;notyetrecorded,3(whichwithvirtually
no question will prove to be 1 Fagaceae, 1 Juglandaceae, and 1 Salicaceae).
FOODPLANT ARENA PROTOCOL
The technique employed here was the “foodplant arena,” in which both
potentiallysuitableandpresumablyunsuitablefoodsareofferedtolarvae,which
29(3):173-194, 1990(91) 175
thenmustmakeachoiceforfeeding(seeGall, 1987). Smallbranchesfromyoung
(2-5cmdbh)foodplanttreesarecollectedlateeachafternoon,ca. 1-3weeksafter
budburstinspring. Neardusk(thetimeatwhichCatocalalarvaebecomeactive
and begin feeding), pieces ofleaves ofdifferent plant species are clipped from
their petioles and taped by one edge to a paper strip (food choice items being
orderedatrandomalongthestrip), andthestripcoiledandplacedflushagainst
the wall ofa small glassjar. Several young larvae are then introduced to the
bottom ofthejar (variation in foodplant preference amongindividual larvae of
the same Catocala species is not pronounced, and the total amount of leaf
materialineachchoiceitemis morethanthe maximumthatthe severallarvae
canpotentiallyconsume;Gall, 1987). Stripsareremovedthefollowingmorning,
andlarvalrestinglocationsandtheamountofdifferentfooditemsconsumedare
used to calculate preference.
Two types ofcontrol foods were offered in each arena. Type I controls were
plant species from a Catocala foodplant group other than the group being
examined: red/scrub oak or lombardy poplar for the Juglandaeeae-feeding
Catocala shagbark/pignuthickoryorlombardypoplarfortheFagaceae feeding
;
Catocala; and red/scrub oak or shagbark/pignut hickory for the Sali—eaceae-
feedingCatocala Type II controlswere“entirelyinedible”plantspecies ones
.
notcloselyrelatedtopresentfoodplantsofanyCatocala. TheType IIcontrolin
arenas was typicallyplantain (Plantago major L.).
Foreacharenatest, the areaoffoodconsumedperchoiceitemwasexpressed
as a percentage ofthe total area consumed, preservingrelative between-choice
differenceswhileassigningunitweighttoeacharenatest. Forfirstinstars,the
amounts eaten were measured using a dissecting microscope fitted with an
oculargrid. Forpartiallygrown larvae, a clear plastic ruled sheetwas used.
INTERVENING FACTORS IN FOODPLANT ARENAS
Problems typically confronting foodplant preference studies include, among
others: (1)thegeometryofhowtopresentfoodchoices; (2)howtominimizethe
effectsofgeo-andphototaxis;and(3)howtoinsurethatlarvaeareawareofand/
orhave“tested”allavailablefooditemsastheyarebeginningtofeed. Formany
lepidopteran larvae, these present serious methodological obstacles, and, in
general, the more polyphagous and/or sedentary a species one tests, the more
significantthese obstacles are likelyto be. Abriefsummary ofthese variables
as theyrelate to Catocala is relevant. —
In all instars, Catocala larvae are extremely active within moments of
introducingthemtoafoodplantarena,theytypicallytraversetheentireperim-
eterofthejar.Whenplacedinarenasduringthedaytime,thelarvaeeventually
settledownafterafewminutes,onornearafooditem,andrest. Whenintroduced
atdusk, thisinitialperiodofrapidmovementalsoincludesmandibularcontact
and/or momentary chewing on leaves encountered. Again, after a period of
usuallylessthanfiveminutes,thelarvaehavepassedseveraltimesaroundthe
arena, andstartto settle andfeed(ratherthanrest). The distributionoflarvae
in arenas remains largely stable from that settlingperiod on through the next
morning, when arenas are disassembled.
MostCatocalalarvaearepositivelyphototactictosomedegree. Ihavealways
foundmaturelarvaetobesomewhatlessactiveduringthedaythanfirstinstars
(seeWojtusiak, 1979, fordiellocomotoractograms ofCatocalafraxini L. larvae
ofvarying ages). Starting arena tests at dusk or night, in dark rooms, largely
eliminated problems with phototaxis (all laboratory preference tests were con-
176 J. Res. Lepid.
ducted under uncontrolled, but essentially natural photoperiod). Note that
Catocala larvaebecomeactiveandcommencefeedingattrue duskeveninfully
lit rooms with no windows.
Ininitialtrials, the geometryofhowfoods were presentedhad no discernible
effectonlarvalfoodplantpreference.Totestthis,leaveswerepresentedhanging,
asabove,orflatonthebottomofthearena. Foodplantpreferenceswerethesame
in three such paired tests (n=4 arenas per test) for the Salicaceae-feeding
Catocalacara Guenee, andtheJuglandaceae-feedingCatocala neogama Smith
and Catocala retecta Grote (p>.25 for each byANOVA). Foods were presented
hangingin all subsequent trials.
FIELD REARING PROCEDURES
ToassaySurvivalanddevelopmentratesonfoodplantsinthefield, Iconfined
larvaetolargerearingexclosures(“sleeves”)onbranchesofdifferentfoodplants.
Sleevesweremadeofeitherlightweightmuslinorfinenylonnetting,andvaried
in size dependingupon the number and age oflarvae confined in them. Equal
numbers of newly hatched, unfed larvae were placed in sleeves on suitable
foodplants, thegeneticbackground oflarvaeforeachrearingexperimentbeing
controlled by splitting the progeny of a single female among the sleeves.
Environmental differences were controlled, insofar as possible, by selecting
sleeving sites at which all foodplants for an experiment were growing in
immediate proximity. Larval instar was used as the growth index, and was
assayedbyusingbothheadcapsulewidthandtheinstar-specificmorphological
patternsofCatocalalarvae. Eachinstarwasfurthersubdividedintoanearlyand
late stage, whichwas assayed usingbody size.
TheprimaryresearchsiteforlarvalrearingwasWestRockPark, threemiles
west ofthe Yale University campus. This is an open-canopied, xeric to mesic
igneoustrap-rockridgetophabitat(Gall, 1987). WestRockisnearthenorthern
limit for many elements ofmore southerly biota and in addition contains the
usualfaunaandfloraofsouthernNewEnglandbroadleafforests. Thecanopyis
dominated by oak, hickory, and ash, with a sparse understory of rosaceous,
ericaceous, and other shrubs.
It should be noted that when sleeve rearings were initiated in 1980, 1 began
measuring developmentrate as the numberofdays elapsed fromfirst sleeving
untilpupation. In 1980, andespecially 1981, theessentiallytotaldefoliationof
theWestRockstudysitesbytheintroducedpestgypsymoth Lymantriadispar
(
L.)terminatedmostsleeveexperimentsbeforetheCatocalalarvaecouldsuccess-
fully pupate, and re-sleeving was impossible. Hence, the measure ofdevelop-
mentrate was soon switchedto larval instar atthe time ofsleeve census.
CATOCALA AND FOODPLANT SPECIES STUDIED
Arenaandrearingtestswerecarriedoutfor19Juglandaceae-feedingCatocala
species: angusi Guenee, dejecta Strecker,flebilis Grote, epione Drury, habilis
Grote, insolabilis Guenee,judith Strecker, lacrymosa Guenee, luctuosa Hulst,
nebulosa Edwards, neogama, obscura Strecker, palaeogama Guenee, piatrix
Grote, residua Strecker, retecta Grote, subnata Grote, ulalume Strecker, and
viduaSmith. Hickories(CaryaNutt.)andwalnuts(JuglansL.)arethefoodplants
ofthese Catocala. Because the generic abbreviation (“C.”) is the same forboth
CatocalaandCarya,byconventionIdroptheabbreviationwhenreferringtothe
moths,andretainitforthefoodplants. Amongthefourhickoriesofferedinarena
29(3):173-194, 1990(91) 177
tests were three Carya from section §Eucarya DC. shagbark hickory, Carya
:
ouata(Mill.) K.Koch;pignuthickory,Caryaglabra(Mill.) Sweet;andmockernut
hickory,CaryatomentosaNutt. ThefourthwasaCaryafromsection§Apocarya
DC.: bitternut hickory, Carya cordiformis (Wang.) K. Koch. Two species of
Juglanswereofferedtolarvaeinarenatests: blackwalnut,JuglansnigraL. and
;
butternut,J. cinerea L.
Arenatestswerealsoconductedwith12otherCatocalaspecies. Includedwere
7 Salicaceaefeeders: amatrixHubner,cara,concumbensWalker,meskeiGrote,
partaGuenee,relictaWalker,andunijugaWalker. Foodchoicesofferedtothese
species included: black willow, Salix nigra Marsh.; pussy willow, S. discolor
Muhl.; cottonwood, Populus deltoides Bartr.; quaking aspen, P. tremuloides
Michx.;bigtoothaspen,P.grandidentataMichx.;andlombardypoplar,P. nigra
var. italica Muench. Preferences were also determined for 5 oak-feeding
Catocala arnica Hubner, coccinata Grote, ilia Cramer, lineella Grote, and
:
micronympha Guenee. Foods offeredinthe red oak subgenus Erythrobalanus
(.
Spach) included: red oak, Quercus borealis Michx.; scarlet oak, Q. coccinea
Muench.; and scrub oak, Q. ilicifolia Wangenh. Foods offered in the white oak
subgenus Lepidobalanus Endl.) included: white oak, Q. alba L.; chestnutoak,
(.
Q. prinus L.; and post oak, Q. stellata Wangenh.
STATISTICAL PROCEDURES
Data analysis was done on either an IBM 3083 mainframe or an IBM/PS2
Model 70 microcomputer, using SAS Version 5.16 and SAS/PC Version 6.03,
respectively(SASInstituteInc., 1985a,1985b). TheGLMprocedurewasusedfor
analysis ofvariance, with a posteriori comparisons ofmeans done by Tukey’s
HSD (results using Tukey tests were comparable statistically to those from
Bonferroni and Duncan multiple-range tests, and each returned the same
biological conclusions). Percentage data were arcsine square roottransformed
priortoanalysis. MostnonparametricanalysesusedtheNPAR1WAYandFREQ
procedures, butininstances where expected cell sizeswerefive orless, andthe
number of cells was also small, Fisher’s exact tests and/or exact binomial
probabilities were calculated. For these, I used my own analysis offrequency
routinesprogrammedinREXXandFORTRANfollowingthemethodsofSokal&
Rohlf(1981).
Results
ARENA TESTS: FIRST INSTARS
1. General Patterns
Reactions oflarvaetoType I andType II controlswerequite different.
That the larvae of all Catocala species readily discriminated between
potentially suitable and unsuitable foods is shown by the minuscule
amounts ofType IIcontrols eaten; similarly, thatlarvaeidentifiedtheir
own foodplant group correctly is shown by the low amounts ofType I
controls eaten (Figures 1-3).
Table 1 shows the (Spearman rank) correlations between amounts of
food eaten and larval resting sites in arenas. While these resting sites
tendedtobe onthe sameleaves atwhich larval feedingoccurred, itwas
apparent from the outset of this research that resting site was an
insensitive index ofpreference. The correlations for the Juglandaceae
178 J. Res. Lepid.
Table 1. Mean correlation between resting positions on foods in arenas and
amountsofsamefoodseatenbyfirstinstar Catocalalarvae. R=Spearman
rank correlation coefficient. N = total number of arenas. Correlations
calculated for each arena, then pooled by species.
Species r n Species r n
habiiis 0.77 4 amatrix 0.95 4
judith 0.75 8 cara 0.72 5
obscura 0.83 9 concumbens 0.55 6
residua 0.83 8 meskei 0.54 3
parta 0.56 8
epione 0.65 11 relicta 0.65 14
palaeogama 0.70 11 unijuga 0.65 5
retecta 0.64 10
vidua 0.64 7 arnica 0.59 3
coccinata 0.86 8
subnata 0.96 11 ilia 0.42 6
lineella 0.76 4
neogama 0.70 4 micronympha 0.62 5
feeders are greater than those for either the Salicaceae or Fagaceae
feeders (pc.01 in each case, by Mann-Whitney U-tests using data from
individual arenas). The low correlations for several oak feeders are in
partduetosmallsamplesizes,whichareinturnduetothehabitsofthose
larvae to rest away from the food choices (on arena walls, and so forth).
This clearly reflects real biological differences in preferred natural
restingsites (e.g., offthetrees, as inilia). The lowercorrelations forthe
Salicaceaefeedersarenottraceabletolowersamplesizesaswiththeoak
feeders. Again,someoftheseSalicaceaefeedersdoubtlesstendtorestoff
theirfoodplants,buttheirnativelarvalbiologiesremainlessthoroughly
investigated.
2. JUGLANDACEAE-FEEDING CATOCALA
Figure 1 shows foodplant preferences for 18 Juglandaceae-feeding
Catocala species (data are from a total of 134 arenas, involving larval
broods from 45 different female moths).
Onlyneogama andpiatrixpreferredJuglans overallotherfoods, each
eatingblackwalnut(<J. nigra) andbutternut(J. cinerea) nearlyequally.
Unfed, newly hatched larvae offive neogama broods refused to feed on
either Carya ovata or Carya cordiformis, even when no other food was
offered. Although piatrix larvae ate more Juglans than Carya, they
clearly tolerated hickories better than did larvae ofneogama.
Larvae of subnata and nebulosa preferred bitternut hickory, Carya
cordiformis. Their distantly second-ranking food choice next to C.
cordiformiswasJuglansnigra. Unfedfirstinstars ofthreesubnata and
two nebulosa broods refused to eat any Carya and barely nibbled on
,
Juglansnigrawhenonlyitwasofferedasfood;larvaeofeachspeciesalso
0
0
29(3):173-194, 1990(91) 179
<8
I R
0
O O
angusi O. 0. 0.0.
n=5,m=U,pfi-1.05 (3. 0O
habilis i 0 0 O 0.0
rv=8,m=162, pf1=1.12 d 0. 0 O 0 0 00
iudith
n=11,m=l79, pf1=1.06 00 00
.
d 0
obscura 0. 0.
rv=8,iw=246, pfi=1.95 0
•
00. 00. 0,0
residua
n=8,m=417,pfi=2.69
O0
O
0.0.0
deiecta 0.0.
n=4, ro=Z74, pf=0.81
0
0
epione 0. 0.0. 0.0.
n=11,ra=748, pfi=0.47 .
0 0. 0 O O 0
flebilis 0.0.
n=5.m=66, pfi=0.76 . O0
0 O
insolabilis 0. 0. 0.0.
n=3,m=65, pfi=0.83 0 0 0 o©
©o.
laerymosa 0.
n=6, m=67, pfi=0.66 0 0 0 0 00
palaeoaama
0.
n=13, m=358. pfi=0.B1 00.0 0 00. .. 0
reteeta
0.
n=17,m=226, pfi=0.93
0 0 0 O O 0
ulalume 0.0.
n=2,m=219.pfi=0.72
0.00 o 0 0
vidua 0.0.
n=8, iii=273, pfi=0.68 . .
Fig.1.Foodplantarenaresultswithpreviouslyunfed firstinstarlarvaeofJuglandaceae-
feeding Catocala Areasofpies proportionaltoamounts (percent) offood
.
eaten;dot incenter=food notoffered. Pies havingthe samesubscripted
lettersarenotsignificantlydifferent atthe0.05level (Tukey HSDtests). N
=total numberof arenatests. M = mean amountoffood eaten perarena
in square mm. PFI = preferred foodplant index, here measuring
preference of C. ovata relative to other Carya foodplants (see text for
elaboration; the greaterthe PFI the greaterthe preference).
—
,,
180 J. Res. Lepid.
Figure 1 continued
-Ohi uoM
52 «M m H MM
i i i 50B3Ou 3?WPlf»®oiM| HS©36H2 g« gm
~
o •
“ o. o. 0.0. 0.0.
4
0.0.0
0.0. 0.0.
™
© O
©. O. 0.0. 0.0.
~
O
0. 0. 0. 0.0. 0.0.
acceptedpecan,Caryaillinoiensis(Wang.) K.Kochofsection§Apocarya
butthis foodplantwas notusedin arenas due to lack ofmaterial (pecan
is not native to Connecticut).
The other 14 Catocala species preferred Carya to other foodplant
genera(seebelowforresponsestoCaryacordiformis,whichwasusually
omitted as afood choice in their arenas). All butepione consumed more
C. ovatathananyotherCarya andlarvaeof5ofthe 14species angusi
, —
hahilis, Judith ohscura, and residua showed quite pronounced
,
preferences for C. ovata. This penchant for C. ovata is quantified in
Figure 1 bya“preferredfoodplantindex”(PFI), whichis here definedas
the amount of C. ovata consumed divided by the sum of all Carya
consumed. The PFIis higherforthe setoffive species includingangusi,
habilisJudith, obscura, and residua than forthe remainingnine Carya
feeders (u=0, nl=5, n2=9, pc.05 by Mann-Whitney IJ-test).
It is notable that only epione did not eat substantially more C. ovata
than other Carya. In contrast to the other 13 Carya feeders examined
(especially the taxa with larger numbers ofarena tests), epione did not
consumeJuglans as its second-rankingfooditemnexttoCarya. Infact,
epione was the only Juglandaceae feeder that ate significantly less
Juglans than it did its Type I Quercus/Populus controls (u=12, nl=8,
n2=8, pc.05byMann-WhitneyU-test;the amounts ofcontrolfood eaten
were nevertheless meager).
Among the Carya §EucaryaJeeding Catocala, the preference for C.
ovata is pronounced, anditis thus germaneto ask: whatpreferences do
these larvae exhibit if C. ovata is unavailable in arenas? Several
additionalarenaswereruninwhichCaryacordiformisreplacedC.ovata.
29(3):173“194, 1990(91) 181
In such arenas, test larvae ofJudith palaeogama, and residua each
,
increasedtheirconsumptionofC. tomentosaandJuglans,whilerefusing
to eat Carya cordiformis. Indeed, in otherno-choice rearing situations,
unfed first instars of all North American Carya §Eucarya-preferring
Catocala refusetofeed significantlyonCarya§Apocarya whenonlyitis
offered (my unpublished rearing and field data; see also below under
sleeve results). Larvae of neogama also refused to feed on Carya
cordiformis (see above); larvae oftwopiatrixbroods acceptedthis plant,
although they did not feed as readily as whenJuglans was offered.
Larvae ofluctuosa (one arena test only) preferred C. ovata two to one
overallotherfoods,butthelarvaeatemuchlessleafmaterialintotothan
didlarvaeofallthe otherCatocala speciestested. Moreover,luctuosa is
theonlyCarya£Ezmarya-preferringJuglandaceae-feedingCatocalathat
showed poor(40-60 percent) survival as larvaewhenreared onC. ovata
indoorsinthelab(thesurvivalrateIobtainwhenrearingallotherCarya
feedersindoorsis neverlessthan 75-80 percent). Initial fieldworkwith
luctuosa in Tennessee in 1987, and its geographic distribution in the
Nearctic indicate that this Catocala likely specializes on shellbark
hickory, Carya laciniosa (Michx.) Loud ofsection§Eucarya.
Testlarvae ofthree oftheJuglandaceae feederswere offspringfrom a
single mother: dejecta nehulosa and ulalume. Significant (p<.05 by
, ,
ANOVA) between-brood differences in preference existed for five ofthe
remaining species: epione hahilis, ohscura palaeogama and retecta.
, , ,
The significances forhabilis andobscura were traceable to one evening
of tests in 1980, in which the arenas became waterlogged (the larvae
rested on and ate mostlyJuglans). The between-brood differences were
morerobustforepione palaeogama andretecta. Thesethreespeciesalso
, ,
show the widest breadth in foodplant preference as both young and
mature larvae (see below). However, no consistent patterns emerged
when the known oviposition histories ofthe brood mothers were com-
pared to the foodplant preferences oftheir larvae (see Gall, 1991b; the
principal finding being that C. ovata best supports larval growth,
regardless offemale oviposition history).
3. Salicaceae-feeding Catocala
Figure 2 shows foodplant preferences for the 7 Salicaceae-feeding
Catocala(dataarefromatotalof47 arenatests,involvingoffspringof12
different females).
Only cara preferred willows over poplars. Larvae of cara did not
discriminate among the willows offered. The introduced lombardy
poplar, Populus nigra var. italica was the first-ranked food item for
,
amatrix meskei, andunijuga,butforonlyamatrixwasthis significantly
,
so (I regularly collect larvae ofamatrix on this plant in the city ofNew
Haven). Larvae of concumbens parta, and relicta all ate Populus
,
deltoidesastheirfirst-rankedfood,withthispatternbeingsignificantfor
concumbensandrelicta. AllSalicaceae-feedingspeciesexceptformeskei
0
182 J. Res. Lepid.
O0
O
amatriy 0. I 0. 0.0.
n=4, m=101
0 0 0
cara 0. 0. 0.0.
n=6, m=241 . .
0 0
concumbena 0. 0. 0.0. 0.0.
n=6, m=58? . .
0 0 0 ©.© ©o.
meafcei ©.
rv=3, m=267 . .
0 0 ©0. ©o.
parts 0. 0.
0=8, nv=442 0 0 .
©O.
relicta 0. 0. 0.0.
n=!4, m=296 0
0
unijuqa 0. 0. 0.0. 0.0.
n=6, m=329 ,
Fig. 2. Foodplantarena resultswith previously unfed larvae ofSalicaceae-feeding
Catocala. Areas ofpies proportional to amounts (percent) offood eaten;
dotin center=food notoffered. Pieshavingthesame subscriptedletters
arenotsignificantlydifferentatthe 0.05 level (Tukey HSDtests). N -total
numberofarena tests. M=meanamountoffoodeatenperarenainsquare
mm.
ate more ofthe Type I control (Carya/Quercus) thanthe Type II control,
and no species ate more Type I control than anysalicaceous food.
Three ofthe Salicaceae feeders were represented by a single mother:
cara,concumbens,andmeskei. Oftheremainingfourspecies,onlyrelicta
showed significant (pc.05 by ANOVA) between-brood differences in
preference. The oviposition histories ofthe relicta brood mothers were
not known.
4. Quercus-feeding Catocala
Figure3showsfoodplantpreferencesforthe5Quercus-feedingCatocala
(dataarefromatotalof36arenatests,involvinglarvaefrom 12different
females).
Thefoodplantpreferences oftheoak-feedingspecieswereless sharply
defined than those of either the Juglandaceae or Salicaceae feeders.
