Life history and biology of Forbestra olivencia (Bates, 1862) (Nymphalidae, Ithomiinae)

2006·4 MB·

Volume 60, Number 4 203
JournaloftheLepidcrpterists Society
60(4),2006,203-210
LIFE HISTORYAND BIOLOGY OF FORBESTRA OLIVENCIA (BATES, 1862)
(NYMPHALIDAE, ITHOMIINAE)
Ryan Hill
I.
3060ValleyLifeSciencesBuilding,DepartmentofIntegrativeBiology,UniversityofCalifornia, Berkeley,CA94720
email: [email protected]
-ABSTRACT. Forbestraistheonlymechanitinegenuslackingathorough lifehistorydescriptionandlittleisknownofitsbiologv. Accord-
inglyIdescribetheimmaturestagesincludingfirstinstarchaetotaxy,andprovideobservationsonthebiologyofForbestraolivenciafromGarza
CochaineasternEcuador. MorphologicalcharactersfromdieearlystagesofForbestraolwenciaareidentifiedthatareuniquetoForbestraand
supportthecloserelationshipofForbestraandMechanitls. ForbestraolwenciawasamoderatelycommonbutterflyatGarzaCochaduringthe
sample period, far outnumbering other sympatric Forbestra. Ecological observations demonstrate similarities between F. olwencia and
Mechanitis,butsuggestF. olwenciaismorerestrictedtoshadedmicrohabitats.
Additionalkeywords: Mechanitini,Mechanitis,chaetotaxy
Introduction Materials and Methods
Ithomiinebutterflieshaveplayedanimportantrolein Observations were made intermittently between
W
the development of mimicry theory, having been the 2000-2005 at Garza Cocha (S 00°29.87\ 76°22.45'),
original models ofimitation describedbv Bates (1862). Provincia Sucumbios, Ecuador. Early stages were
In that paper Henry Bates described Mechanitis reared in plastic cups and plastic bags under ambient
olivencia based onwingcolorpattern differences being conditions (22-30° C, 70-100% relative humidity) in a
consistently' different from other sympatric Mechanitis wood buildingwith screen windows. During the drier
in the western Amazon basin. Forbes (1924) noted parts ofthe year (December to February) larvae were
characters ofthe colorpattern, wingvenation, and male moveddailyfrom thebuildingto ashadedenvironment
genitalia that distinguished "equicola and allies" from underanearbybuildingto maintainambientconditions.
"polymnia and allies". Fox (1967) erected the genus Observations were recorded daily and head capsules
Forbestra to contain "equicola and allies", including and pupal exuviae were collected. Larval specimens
olivencia, and identified characters of the female were boiled and subsequently stored and studied in
forelegs as distinct from Mechanitis In the 40 years 70% ethanol and deposited in the author's collection.
.
since its description little has been published on the First instar head capsuleswere treatedwith 10% KOH
biologyofspecies in the genus Forbestra, despite their to dissociate the mandibles and labrum. Host plant
being among the larger and more conspicuous vouchers were collected and depositedin the Herbario
ithomiines. Nacional de Ecuador (vouchernumber: RIH-596).
Recent systematic work on ithomiines has used Observations on adults were made at the same
characters from the early stages in phylogeny localityin the surrounding forest. Adults were marked
reconstruction (Brown & Freitas 1994, Motta 2003), and released, or collected forother studies. I recorded
makinguse ofthe factthat life historydataare available flight height, microhabitat conditions, and adult diet.
fornearlyallgenera. Photographsoflarvae andpupaof Forewinglengdiwas measuredwidi digitalcalipers and
F. equicola (Cramer) (Brevignon 2003) and a brief bodv mass was measured with a portable balance
description and drawing ofthe larva ofF. olivencia by (Acculab) accurate to 1 mg. Ithomiine taxonomy
Drummond (1976) are all the life history information follows Lamas (2004), except diat Mechanitis
that exists for Forbestra. Moreover, Forbestra is the messenoides Felder & Felder is treated as a species,
onlygenus lackingathorough life historydescription in ratherthanasubspeciesofM. mazaeus Hewitson,based
the tribe Mechanitini (Freitas & Brown 2002), a group onobserveddifferencesinhostplants, colorpatternand
comprisedofseveral mimeticcolorpatterns andthus of DNAsequence data atthis site (unpublished).
interest for the evolution of mimicry. Accordingly, I
Results
describe the early stages ofForbestra olivenciajuntana
(Haensch) from eastern Ecuador, and include in the Early Stage Biology
descriptions characters developed for phylogeny Host plant. Host plant specimens were compared
reconstruction (Brown &Freitas 1994, Motta2003). In with material in the Herbario Nacional de Ecuadorand
addition, I report observations on the ecology, behavior determined to be Solarium monarchostemon Knapp.
and morphologyofForbestra olivencia. and Michael Nee of the New York Botanical Garden
204 Journalofthe Lepidopterists' Society
confirmed the determination. Forbestra olivencia times to the host leaf surface. Host assessment took
juntana were only found using S. monarchostemon at nearly 10 minutes forone female, and females take one
Garza Cocha. However, Elias and Willmott (pers. to several minutes between laying each egg. Both
comm.) observedF. olivencia usingSolatiumthelopodim females first laid a pair of eggs close together, then a
Sendtn., in additionto S. monarchostemon, south ofthe single eggon adifferent leaf.
Rio Napo nearAnangu. Descriptionofearlystages:Egg. Fig. 1A. Duration:4(n= 1)to5
days(n= 15). Meaneggheight1.59mm,meanwidth0.87mm,with
recItorsdheodualtdLibmeonncootcedhatihsantotthSeolahtoisutmoafncFe.psolRiuviezn.ci&a mtheaannwaixdees,rwaitdieos(theiingmhitd/wdildet,h)taopfer1i.n8g3a(pnic=al3)l.ytTohneaergrgowisbwuhtitreo,utnadlleedr
Pav. as reported in Drummond (1976) and Drummond apex. Eggsurfacesculpturedwith13-17horizontalridges(n=4)and
& Brown (1987). The host specimen (Drummond r1o3-u1n5devedrtiocfaflr(iFidgg.es1(An)=.4)Tmhaekinfogufro-usri-dseiddecdelclellpsawtittehrnincnhearncgoersnertso
7315) listedin Drummond (1976)wasstudiedbyKnapp pentagonalandhexagonalcellsnearapex.
(20S0o0l)atainudmdemtoenramricnheodsttoemboenS.wmaosnarfcohuonsdteimnonp.rimary b(lna=c1ks6.t).inMsBteoaadr.nyhFsiepgaa.drsIceBalpyasnucdloeFviwegir.det2d.hw=Diu0tr.ha5t4idomanr:mk2(sndeat=yase1.4()n.=BHo1e5da)ydtocisa3psdpuaalylese
forest inwell-drained, well-lit areas and associatedwith translucentwithbluetintsateitherend,bluepalestinposterior. Body
gaps. Individuals hosting F. olivencia were 0.5 - 1.3 m palelaterallywithyellowtintsanddorsumgraytogreenwhereplant
material visible. Anterior ofsegment Tl whitish. Rounded lateral
tall, often with flowers and/or fruits, and found in protuberance present on abdominal segments Al-8. Dorsum
shaded areas neargaps, butnotatgap edges orin gaps. traversedbysubtlefleshywrinkles. SegmentA10withdarkanalplate.
A group ofsix Mechanitis messenoides eggs was found Thoraciclegsaredark. ProlegspalewithdarkpatchatbaseandA10
on S. monarchostemon and reared to be normal sized pqruaorlteegrbsaosfeedgagrskheerllth(ann=ot4h)eorsr.whNoelwelyeghgashteclhled(nla=rv3a).eeRaetsotnweittohdbiordeye-
adults. straightonundersideofleafalongsecondary'ortertiaryleafveins,or
Ants were commonly found patrolling Solarium nearholeinleaf. Larvaesometimeseatintoleafaroundthemselves
makinganisolatedpatchofhosttoreston(seeFig. IB).
monarchostemon. Ectatomma, Crematogaster,
Becausecharactersbasedon firstinstarmorphologyhaveproven
Wasmannia, Camponotiis (identified using Bolton informative forithomiine phylogeny (Brown & Freitas 1994, Motta
1994), and three unidentified genera were collected 2003),andForbestrawasmissinginMotta's(2003)analysis,Iprovide
from thehosts. Crematogasterwereobservedattacking TahdeetdaeislcerdidpetsicornipftoicounseosfotnheMoftirtsat'isns(t2a0r03c)hameotropthaoxyloignictahleAchpapreancdtiexr.s
and carrying away PI olivencia eggs on one host. so the description may be used for phylogenetic analyses. The
Ectatomma and other genera were not observed descriptionisbasedontwopreservedfirstinstarsandthreefirstinstar
interacting with eggs or larvae, and one female F. sheetaadecaarpessulheosw.nAirnrFaign.ge2.mentandrelativelengthsoffirstinstarbody
olivencia oviposited on ahostwith Ectatomma present. 2ndinstar. Fig. 1C. Duration: 1 day(n = 2) to2days (n = 13).
In addition to ants, an unidentified species ofbraconid Meanheadcapsulewidth = 0.74mm (n = 17). Likepreviousinstar
wasp was observed searching S. monarchostemon and yweiltlhotwhleatferoalllloy.winTglcihsapnagleesd.orsBaoldlyywlietshsbtlruaenstliunctse,ntanadndfitpsaslneugtloypwailteh-
larvae ofadifferentbraconidspecies emergedfrom 4th posterior of head capsule. Aorta is visible dorsally. Middle body
instarP olivencia. segments dorsallygray-green where foodvisible. PosteriortoA6-7
Oviposition. Eggs are laidon the upperleafsurface, pthreotduboerrsaunmceisonpalAe3-t6oryoeulnlodweids,htthuorsneinognbAllu-i2shaonnd AA78--98.areLamteorrael
but one eggwas observed on the host plant main stem. pointed and larger, with those on Al-2 largest. Thoracic legs and
Eggs were found laid singly (n=7), in pairs (n=ll), and prolegsarepalewiththoraciclegsdarkerthanprolegs. Oneindividual
observed eating circle into leafaround itselfon underside ofleaf.
occasionally in clusters of three (n=3) or four (n=3). Commonly rest on leafunderside with body straight, lying along a
One group ofeight eggs was also found. Host plants secondaryveinwithheadawayfromleafmidvein.
w(9eroeutcoofmm1o3npllyanftso)u,ndcowmitmhoneglgystownomoofrethtehlaanrgoenrehloesatf cfaopl3slourwldienigwniscdthtaarhn.g=esF.1i.g0.6ThImoD.rmax(Dnudro=artsi1uo2)mn.:n2eLairdklaeyyspwrh(einvtie=ouis1n1)ia.nnstteMarreioawrintohhfetTahlde
leaves. Eggs were found on small to large mature host turningblueinposteriorTl,thenfadestograyinT3. Thoraxiswhite
leaves with little to extensive herbivore damage. As laterally. Restofbodygrayish dorsally, turningblue again onA8-9.
mentioned above, eggs and larvae were not found on Segment A10 white dorsally and laterally. Lateral abdominal
protuberances yellowish in color, except for on A8, which is white.
plants in orborderinggaps. Lateral protuberances are rounded triangles with Al-2 longest and
Two oviposition events were observed at 11:00 and thinnerthan rest. Ventrallypale translucent. Reston undersideof
leafon midveinwith bodystraight. When disturbed raiseheadand
14:30respectively, andfemaleswereobservedsearching
thoraxoffleafsubstratemaintainingstraightposture.
forhosts between 11:00 and 16:00. Females search the 4th instar. Fig. IE. Duration: 2 days (n = 11). Mean head
hostverycarefullyforseveral minutes, hoveringinfront capsule width = 1.44 mm (n = 9). Like previous instar with the
followingchanges. ApairofsmalldorsalhumpspresentonTl. Tl-2
of leaves and main stem, inspecting both top and bluedorsallyandlaterally. AnteriorofT3faintbluedorsally,fadingto
bottom ofleaves and also descending slowly nearly to lightgray. T3paleyellowlaterally. Al-7yellowishgraydorsally. A8-
the groundwhile facingthe main stem, then ascending 10 blue dorsally, with AlO's posterior fading to pale. Lateral
to leafheight. Upon settling on a host leafthe female plornogtuabsetrhaonsceeoonnAA3l--A28.tapAe3r'isnlgatteortalhipnrfolteusbheyrparnocjeecltoinognesatboouftAt3w-i6cebuats
tests with antennae and touches her abdomen several shorterthanA7-8. Al-7lateralabdominalprotuberancesyellowish.
Volume 60, Number4 205
Figure1. Forbestraolivenclalifehistory. A. Leaf-topclusterof3eggs(imageisacompositeoftwophotosofsameclutchofeggs),inset
iseggdrawnfromspecimenafterstoragein70%ethanol. B. Firstinstar. C. Secondinstar. D.Thirdinstar. E. Fourthinstar. F.Fifthinstar.
G.Lateralviewoffifthinstarshowingdarkthoraciclegsanddarkpatchesonprolegs3-6. H. Pupawith firstdaycoloration. I.&J. Final
pupacolorationindorsolateral(I)andventralview(J).
1
206 Journalofthe Lepidoptemsts' Society
yellowstrongestonAl-2andA6-7. AS'slateralprotuberanceispale. thatareseparatedintopairsonsegmentsA2,A8,A9,partiallvfused
White stripe present on dorsal midline ofabdomen. White dorso- onsegmentsA3andA7andcompletelyfusedformingonelargespot
lateralstripepresentaboveabdominalprotuberanceonsegmentsA3- on segments A4-6 (arrow in Fig. II). A few individuals had dorsal
6, dien fading on A™. Rest on leafunderside with head down and blackspotsincompletelyfusedonA6. Togetherthispatternmakesan
bodystraight. Atrest,headcapsulepartlyobscuredindorsalviewby elongate narrow "X", with arms of "X" more widely separated at
Tl. Feed from leaf margin near its apex. Braconid wasp larvae anteriorend. Inbetweendorsalabdominalsegmentscoloredorange-
emergedfrom4thinstarsandresultedinlarvalmortality. brown. Transverse ridge present in anterior ofA3 making a small
5th instar Fig. IFandG. Duration:4days(n= 7)to5days(n= shelf. Antennae edged in black line that is broken into dashes in
3). Meanheadcapsulewidth=2.00mm(n=4). Likepreviousinstar middlethirdonly. Wingpadedgedblackventrallyfadingcompletely
with the following changes. Head capsule black with pale aftermid-length. Wingpadedgedbrownandblackdorsallvturning
pubescence,suturesvisibleaslightlines,andlabiumlightgray. TTs to dashed black line and ending nearapex. Wingpad marked only
dorsal fleshy humps more pronounced. Tl-2 blue dorsally and with thin black line near center. Thorax weakly keeled. Thoracic
laterally. T3dorsallydarkerthanTl-2,andpaleyellowlaterally. A7 dorsum colored with broad black stripe that splits around a brown
posterioris blue dorsally. Dorsum ofA8-9 blue, but AlO's whitish. patch in posterior. Anterior to black band of keel are two black
AbdomensegmentsAl-7yellowlaterallyincludinglateralabdominal roundedsquares. Additionalpairofblacksquares locatedatbaseof
protuberances,yellowextendingontodorsum. A8-A10palelaterally. antennae,andblacktrianglespresentonslightlypointedocularcaps.
White dorso-lateral stripe above lateral protuberance starting in The daybefore eclosion bluish tints develop, thenwingpad margin
posteriorofA2andendinginanteriorofA7(mainlyonA3-6). Lateral developsdistinctblackbeforethewingcolorsfinallyshowthrough.
protuberancesofAl-2andA7withwhitetips. Lateralprotuberance
ofA3-8triangulartobroadlytriangular. ProtuberanceonAl-2twice Adult Biologij: In 204 days of fieldwork at Garza
thelengthofthoseonA4-6. A3,A7,andA8withslightlylongermore CochabetweenJuly-August2000, May-July2001, May-
pointedprotuberancesthanthoseofA4-6. Spiraclesobviousanddark
onTl,Al-8. Dorsumwithcentralwhitetoyellowishlineoveraorta July2002,January-February2003 and December2004-
fromposteriorT3toA7. Aortavisibledorsally, andappearspaleT3- Januarv 2005, 83 individuals ofF. olivencia were seen
A7anddarkonT2andA8-9. Thoraciclegs areblack. Prolegshave (recaptures excluded), 68 ofwhich were captured and
dark gray to black sclerotized plate near base, this not strongly
sclerotized on A6 and A10 in some individuals. Prolegs with pale sexed (21 males, 47 females). F. olivencia ranked 13th
pubescence near base. Pale translucent ventrally with tracheae in abundance out of56 ithomiine species in the overall
vfiasdiebsl.e.WDhaeynbdeifsotruerpbeudpattuicoknhbeoaddyctauprsnusleveurnydyeerllTolw,atontdalbllyuoebsocfubroidnyg rank-abundance distribution ofcapture dataduringthis
headcapsuledorsally. Restheaddownonundersideofleafwithhead period. F. olivencia was much more common than
nearwhereeatingatmargin. Larvaeingroupsof2-4staytogetherin Forbestra equicola during the studyperiod (F equicola
allinstarsandnocannibalismwasobserved. ranked40th with 6 individuals), and a single F proceris
metaPlulpica,.elFoingg.at1eH,anIdapnedndJa.nt.DurAattifoirns:ta8lldyaeylslo(wnw=ith9)o.utRaenfylebcltaicvek (Weymer) was captured outside the study period in
markings other than cremaster. Within first 24 hours black marks June 2005. With respect to other mechanitines, F
developonyellowpupa(Fig. 1H)followedbyyellowturningtosilver olivencia tied Mechanitis mazaeus in abundance and
wliintehegxotledndhiinghglfigrhotmsc(rFeigm.asItIearntdor1Je)g.ioCnrbeemtawseteenrbsleagcmke.ntVsenAtrSalanbdlaAc9k was more common than otherMechanitis. F. olivencia
withpairofbumps, andthereexpandinglaterally,overall makingan was less common than Scada zibia (Hewitson) (11th in
anchor-shaped patch. Anterior to anchor-shaped patch, ventral rankabundancewith 99individuals) and morecommon
abdominalmidlinewithsmallfaintblackspotsthatareabsentinsome
individuals. Ventro-laterally, abdomen has pair ofblack flecks on than Thijridia psidii (Linnaeus) (46th in rank
segments A5-6, segment A6's smaller. Spiracles outlined in large abundance with two individuals). Among ithomiines
csrqeumaarsitsehr.blAacbkdospmoetsndonorsseugmmweintthsseAr3i-e8s,ofdeecigrhetassiqnugariinshsbizleactkoswpaortds with similarmimetic 'tiger' coloration (Beccaloni 1997),
F olivenciawas the third most abundant species.
^* -^ -• ^—
/ s^>
^ '" *
f /
'
/ »
/•: i 4 i
/ /
? y
— s— S o _^> ^s /
if
J— > —f- 1 / r -^ '—} L
T1 T2-3 A1 A2 A3-6 A7 A8 A9 A10
Figure2. Firstinstarbodychaetotaxy. Setaedrawntorepresentrelativelengths.
Volume 60, Number4 207
Forbestra olivencia was lowest in abundance in July-
August2000with onlyfourindividuals (0.11 individuals
per day) and more common in other sampling periods
with 13 individuals during May-July 2001 (0.23
individuals per day), 25 individuals during May-July
2002 (0.47 individuals per day), 19 individuals during
Januarv-Febmarv 2003 (0.76 individuals per day), and
22 individuals during December 2004-January 2005
(0.62 individuals perdav).
Forbestra olivenciainhabits primaryforest. Females
arecommonlyseenflvingintheunderstoryvvitiramean
m
flight height above the ground of 1.0 (n = 39, s.d. =
0.63). Males were observed flving higher than females
atamean height of1.6 m (n = 20, s.d. = 0.86; unpaired
f-test, t = -2.7, P = 0.009). Individuals were observed
only in shaded forest or near small forest gaps.
AlthoughnoindividualsofF. olivenciawereobservedin
open areas, F. proceriswas observedvisitingAsteraceae
flowers in acleared field.
Observed adult resources of F. olivencia at Garza
Cocha include bird droppings, and rarely splattered
fruit orother leaftop detritus. F. olivencia females visit
bird droppings (n = 5; Fig. 3A), and were observed
flving in the immediate vicinity of army ants (Eciton
spp.) stopping at white fungal patches on leaves and
birddroppings. One malewasobservedfeedingon bird
droppings. No F. olivencia were observed visiting
Asteraceae flowers or other pvrrolizidine alkaloid
sources duringthis study.
B
F. olivencia is sexuallydimorphicwith respectto size.
Forewing length ofwild-caught females (mean = 33.88
mm, s.d. = 2.30 mm, N = 27)is significantlylongerthan
wild-caught males (mean = 31.97 mm, s.d. = 2.64 mm,
N = 14; unpairedf-test, t = 2.40, P = 0.021). However
femalebodymass (mean = 72mg, s.d. = 19 mg, N = 20)
is not significantly higher than males (mean = 65 mg,
s.d. = 21 mg, N = 11; unpairedr-test, t = 0.99, P = 0.3). FIGURE3. AdultF. olivenciajuntana. A. Ventralwingpatternof
Mating takes place during the middle of the day as a femalefeedingonbirddropping. B. Dorsalwingpatternofmale
rearedfromlarva.
pair was seen in copula at 13:00 with the smaller
hindwingwith transverse blackbar, and forewingwidi
individual, presumablymale, flying. Forewinglengthof
orange, yellowandblackoblique stripes (Fig. 21.
reared females (mean = 32.80, s.d. = 0.85, n = 4) and Morphology of Forbestra olivencia early stages
males (mean = 31.33, s.d. = 1.88, n = 4) did not differ provides useful characters to identify F olivencia, and
from wild-caught individuals ofthe same sex (unpaired
corroborates both the generic status ofForbestra and
f-test, t = 0.91, P = 0.37 for females, and t = 0.45, P = the sister relationship between Mechanitis and
0.66 formales).
Forbestra. Characters of first instar ehaetotaxv
Discussion developed for phylogenetic analysis described in this
study (Appendix) are not discussed further. In addition
The genus Forbestra ranges throughout the Amazon
basin and Lamas (2004) recognizes three species (F. tMootFt.ao'lsive(n2c0i0a3,)daatnaalyfsoirs,Saiasndroswaleiraewenroet liancckliundgefdroimn
equicola, olivencia, and proceris). Forbestra species
Freitas and Brown's (2002) description of Sais rosalia
participate in "tiger" mimicry complexes with other
earlystages. Thus comparison offirst instarehaetotaxv
ithomiines and heliconiines (Beccaloni 1997, Brown
forall generaofMechanitiniwas not undertaken here.
1988). These species exhibit a combination oforange
208 Journalofthe Lepidopterists' Society
Two characters of F. olivencia early stages appear fleshy humps on Tl (albeit Forbestra olivencia's are
unique to this species. First, the pupa has dorsal black shorter and more rounded than in Mechanitis), and in
abdominalspotsthatmakeanarrow"X"andcompletely the pupa the dorsal abdominal spots lie neardie dorsal
merge only on A4 - 6 (arrow in Fig. II). F. equicola's midline.
black abdominal spots merge on A4 - 8 and no data on The sister relationship ofForbestra and Mechanitis
the immatures ofF proceris are yet available. Second, implies similarities in ecology and behavior between
F. olivencia larvae have elongate lateral protuberances these genera. Observations on F. olivencia at Garza
on Al-2 reminiscent of those along the abdomen of Cocha largely support this. For example, the single
Mechanitis. Such protuberances are not present on F. observation of Mechanitis messenoides using F.
equicola (Brevignon 2003). However, these elongate olivencia's host suggests similartolerances to host plant
lateral protuberances may be variable as Drummond's chemistry. Furthermore, F. olivencia feed on bird
(1976) larval drawing of Forbestra olivencia juntana droppings and follow army ants similar to Mechanitis
(called F. truncata juntana) from Limoncocha lacks (Bay & Andrews 1980). Though the data are few (five
elongateprotuberances on Al-2. females and one male were observed feeding on bird
Like Mechanitis, F. olivencia lays eggs on leaftops. droppings), diey show a female bias in feeding on bird
However, F. olivencia typically lays eggs singly or in droppings as documented for Mechanitis andMelinaea
small clusters of 2 - 4 and not large clusters as in (Bay&Andrews 1980).
Mechanitis. Although there is no information on F. Malesofithomiinespecies avidlyvisitAsteraceaeand
equicola egg clutch size in Brevignon (2003), the fact Boraginaceae flowers and plant parts to gather
that the larvae are together on a single leaf suggests pyrrolizidine alkaloids (Brown 1984a, 1984b, 1987,
equicola also lays eggs in groups of small size (~ 6). Brown et al. 1991, Pliske 1974, 1975). Mechanitis are
Thus the genus Forbestra appears to layeggs in smaller commonly seen feeding on Asteraceae in gaps,
clutches thanMechanitis andadditionalobservationson secondary growth and cleared areas at Garza Cocha.
Forbestra species would clarify whether there are Despite equal effort sampling all species ofithomiines
consistent differences between these genera. and makingobservations in the earlymorningatflowers
ThepupaofForbestra olivencia is strikinglysimilarto fed on by other ithomiine species, F. olivencia was not
Mechanitis messenoides and M. mazaeus at Garza observed feeding on flowers during this study. This
Cocha (unpublished). F. olivencia pupae differ from almostcertainlydoesnotreflectadifferencebetweenF.
those ofMechanitis primarilyinthe arrangementofthe olivencia and Mechanitis and instead is attributed to
rows of black dorsal abdomen spots. In F. olivencia chance. A male Forbestra proceris was found feeding
these spots completelyjoin on segments A4 - 6 making on Asteraceae in an open habitat in the early morning.
an "X" (arrow in Fig. II), and in F. equicola they are Furthermore A. Freitas has observed F. olivencia males
fused on A4 - 8 and separated on A2-3. In M. visitingAsteraceae in the early morning in Brazil (pers.
messenoides and M. mazaeus (and M. pohjmnia Fox comm.).
1967, Fig. 7) the spotscome closetogetheronsegments There does seem to be a microhabitat difference
A4 - A6 but do notjoin and other mechanitine genera related to host plant use between F. olivencia and
have them located more subdorsally (Brown & Freitas Mechanitis species at this site. F. olivencia adults were
1994, Fig. 4F and A. Freitas pers. comm.). Thus, in not observed in open areas or in forest gaps. Solatium
addition to genitalia, wing and leg characters (Forbes monarchostemon was found in and around gaps, and in
1924 and Fox 1967), die dorsal fusion ofthese spots on well-lit areas offorest. F. olivencia eggs andlarvaewere
A4 - 6 is likelyasynapomorphyforForbestra. not found on hosts in gaps or in sunny areas at gap
The close relationship between Forbestra and edges. In contrast, Mechanitis eggs and larvae are
Mechanitis recognized by Bates (1862), Forbes (1924), commonly found on their host plants in gaps and open
and Fox (1967) is supported by characters of the areas, andMechanitis are morecommonlyseenflyingin
immature stages (Brown & Freitas 1994, Fig. 1A) as gaps and very open areas at diis site. Differential
DNA
well as sequence data (Brower et al. 2006). microhabitat use by F. olivencia relative to Mechanitis
Synapomorphies from the immature stages (excluding deserves further investigation as it pertains to a
1st instar chaetotaxy) supporting this relationship correlationbetween microhabitatandmimicry(DeVries
identified by Freitas and Brown (1994) and et al. 1999, Mallet & Gilbert 1995).
corroboratedhereinclude: eggaxes ratio > 1.7, eggs laid Despite the observation that specimens ofForbestra
on upper side of leaf, and laying eggs in groups. In areuncommonin naturalhistorycollections (Fox 1967),
addition, two other characters identified in this study F. olivencia was moderately common at Garza Cocha
supportthis relationship: larvawithapairofshortdorsal during this study ranking as the 13th most abundant
Volume 60, Number4 209
ithomiine. F. olivencia was highest in abundance in the Literature Cited
drier months sampled (December to February) with Bates, H.W. 1862. ContributionstoaninsectfaunaoftheAmazon
0.76 individuals per dayin January-February 2003 and valley. Lepidoptera:Heliconidae.Trans.LinneanSoc.ofLondon.
0.62 individuals per day in December 2004 to January XXIII:495-566.
Beccaloni, G. W. 1997. Ecology, naturalhistoryandbehaviourof
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Thisworkwas facilitatedbyEric Schwartzandthe manage- rosalia(Nymphalidae, Ithomiinae). Lepid. Soc.56:104-106.
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Appendix: First instar chaetotaxy thantomaxillary(ventral)suture(46). GaventraltolinejoiningGl
and03 (47). Gaslightlynearerto equidistantto Gl relative to 03
Inthedescriptionoffirstinstarchaetotaxythatfollowsnumbersin (48). VI equidistantbetween P2and"V"group (49). Stemmataall
parentheses correspond to characters in Motta's (2003) Table 19.2. similar diameter (50). Distance fronfstemmaiii to ivshorter than
S(e1t9a8l4)noamnedncPleatteurrseonfo(l1l9o6w2s)Mwoetrteaa(l2s0o03c)o.nsuHlitnetd.onD(e1s9c4r6)i,ptKiiotncshianreg froMmaintdoiibi,laendaniidtoliaiibr(5u1m).. SSteteammMa2vaelqiugindeidstbaenttwteoenivLaIndavnid(5L22).or
givenhereratherthanatableofcharacterstatesbecauseofperceived alignedwithLI (53). SetaM2subtlyventraltolinebetween Mland
ambiguity or difficulty interpreting some ofthe characters. In the L2 (54). Seta Ml shifted dorsally relative to M2 (55). Distance
following descriptions Tl, 2, 3 are pro-, meso- and metathoracic between Ml setaeequivalenttodistancebetween Ml and M2setae
segments respectively, Al-10 are abdominal segments, and unless (56). SetaM2abouttwiceaslongasMl(57). PunctureS(called"S"
otherwisenotedsetalcharactersapplytoallsegmentswherepresent. inMotta2003,called"P"inPeterson 1962)locatednearertothebasal
Cephaliccapsule. SetaCIequidistanttofrontalandanteclypeal sutureorposteriorborderrelativetoMl andM2(58,61). Puncture
sutures(1). SetaC2nearertoCIthantoamedialimaginaryline(2). SlocateddorsallyandnearlyinlineverticallywithM2suchthataline
SetaC2samelengthatCI(3). SetaFlundoubtedlymoredorsaland connectingthetwowouldbenearlyparalleltoimaginarymidline(59).
medialtoC2(4). SetaFlnearertoC2thanitistocoronalbifurcation MeanangleoflinesconnectingMl,M2andpunctureS40-70°(60).
(5). Seta F2 equidistant or subtly nearer to frontal suture than to PunctureSinlineverticallywithlongestpartoflabrum (Iabrallobe)
imaginary medial line (6). Puncture Fa clearly above seta Fl (7). andveiydorsalofwidestpartoflabrum(betweenLi's)(62). SetaM3
DistancebetweenFapuncturessimilartotfiatbetweenFaandFl(8). ondistalborderoflabrum (63). SetaL2muchnearertoLI thanto
PunctureAFa,andsetaeAF1andAF2allpresent(9). PunctureAFa L3 (64). Seta LI veryslightly distal to widest part oflabrum (65).
medialtolineconnectingsetaeAF1andAF2,formingobtusetriangle Lesssclerotizedregionoflabrumspansnotchtojustbefore M3(66).
with angle between AFa andAF1/AF2 -160° (10). Puncture AFa Lesssclerotizedbasalpatches absent(67). InternalborderofIabral
closertosetaAF2relativetoAF1 (11). SetaeAF1andAF2similarin lobesmoothlycurved(68). Labralnotchangleobtuse (69). Ratioof
length(12). SetaAF2subtlyabovelevelofcoronalsuturebifurcation notchlength(= depth)tooveralllabrallength (labrallobetobase) -
(13). DistanceofsetaAF2tocoronalsuturesameasdistanceofAF1 0.8; ratioofnotchwidth,asmeasuredbetweenM3's,tolabrallength
tofrontalsuture(14). PunctureAaabovelineconnectingAF1andA2 ~0.8(70). Ratiooflabrumwiddi(betweenLi's)tolength(labrallobe
(15). Puncture Aa nearer to A2 than to AF1 (16). Seta A3 just tobase) -2(71). Morethanthreesmallmolarteeth(72). Incisors2
posteriortoimaginarylinebetweenstemmaivandPI;distanceofA3 and3similarlengths(73). Lateralgroovesradiatingfromeachsideof
totheimaginarylinelessthandistanceofA3tostemmaiv(17). Seta 4thincisor,4groovesintotal(74).
Al closertostemmaithaniiandalignedtoslightlyabove stemmai Body. No tubercles present on the thorax (75). Average seta
((1189)).. SSeettaaAA23alliognngeedrwiinthleinmgatghintahraynliAn2ebaentdweLeIn(s2t0)e.mmPauniicatnudreAFP1a lseetnagethonisTlelsswhthiacnhsaeregmneenatrlwyiadstlhoenxgcaesptsefgormetnhetlwoindgtehr(X77D).1CarnodcXheDt2s
ventraltoimaginarylineconnectingsetaeA2andA3 (21). Puncture arrangedinacirclepattern(78)withinnerandoutercrochetssimilar
PanearertosetaA2thantoA3(22). PuncturePbmedialtoimaginary length (79). Prolegs with more that 14 crochets on average (80).
linebetweensetaePIandP2(23). PuncturePbclosertosetaP2dran Cervical sclerite absent on XD1 and XD2 and Dl (81). Seta Dl
PI(24). SetaPIfartherfromcoronalsuturethanissetaP2(25). Seta shorterthanXD1andXD2whichareequivalentinlength(82). Setae
PItwiceaslongaslengthofP2(26). RelativedistanceofpunctureLa SD2andSD1alignedonTl,SD2shiftedslightlyposteriortoSD1on
to seta LI, 1/3 distance between LI and A3 (27). Alignment of T2 andT3, andSD2shiftedveryposteriorto SD1 onabdomen(83,
puncture Laandsetae LI andA3 formingatriangle (28). SetaOl 87). OnsegmentTl setaeLI andL2slightlydorsalofspiraclewith
nearlyin line withi and iv, equidistant to iii and iv; distance ofOl L2 between LI and spiracle (84). Setae Dl and D2 areequivalent
faanrdthversltioghitiilythlaesnsiith(a29n).90A°n(g3l0e).foSremtaed0b2eteqwueiednis0ta2ntantdosstteemmmmaattaaiivv lSeDn1gthasnd(8D5,29o1)n.aSbedtoamSeDn2(8c6l)o.seSrettoaSSDD12ovennttrhaolraaxndbuatliegqnueiddiwsittahntDtlo
andv(31). Seta02longerthanOl and03,withOl and03similar andD2onthoraxbutventralandposteriortoDlandD2onabdomen
lengths(32,33). Seta03alignedtoslightlyventralthanstemmavand (88). Seta SD1 longer than LI and equivalent to L2 on Tl; SD1
groove(34). PunctureOanearlyalignedwithstemmaiandsetaAl equivalent to LI and L2 on T2/3 and abdomen (89, 94). Seta L2
asntdemvemrayvneaanrds0t2em(m3a6)i.(3P5)u.ncPtuunrcetuOrbeeOqbuifdoisrtmainntgtaonvanagnlde0be2tw(e37e)n. Tp2r/e3s,enStDo2nsaengdmeDnlt/s2T1si-mAi8la(r90l)e.ngStehtsaoSnD2otlhoenrgesretghmaenntDsl(a9n2)d.D2SDo1n
SOIinventralendofantennalsocketsothatdistanceofSOI toend longerthanSD2onTl,SD1slighdyshorterdianSD2andequivalent
ofantennal socket is less than 1/2 distance between SOI and S03 toDl/2onT2/3, andSD1 equivalenttoslightlylongerthan SD2on
(38). S02subtlyventraltostemmatavandvi(39). S02equidistant abdomen (93). Seta L2 longer than LI on Tl and equivalent to
tovandvi(40). S03posteriortolinebetween stemmaviand SOI slightlylongerthan LI on other segments (95). Additional SVseta
(41). SOaalignedtoslightlynearertosuturerelativetolinebetween presentonlyonTlandA2(96). SegmentA9relativetoA7/8missing
S03andGl (42). SOafallsonlinebetweenS02andnearestpointof twosetae(oneofLl/2andoneofSD1/2(97). OnsegmentA10seta
maxillary(ventral)suture,SOaisclosertoS03thantothesutureand Dl longest, SD1 andLI equivalentandD2shortest (98). SetaePI
closertothesuturethantoS02(43). SObveryneartotheantennal andSP1bothpresentonsegmentA10(99).
socket (44). Relative distance ofSObto stemmavi and S03 varies
from nearer to stemmavi to equidistant (45). Gl closer to groove