Hemaris aethra (Strecker, 1875) Schmidt, 2018

Schmidt, B. Christian, 2018, Cryptic species among bumblebee mimics: an unrecognized Hemaris hawkmoth (Lepidoptera: Sphingidae) in eastern North America, Zootaxa 4399 (1) : -

Diagnosis of Hemaris aethra

Adult. EXTERNAl dIffERENCES bETWEEN H. aethra ANd diffinis ARE SUbTlE, ANd USUAllY dIffICUlT TO EVAlUATE WITHOUT COmPARATIVE SPECImENS IN HANd; PHOTOgRAPHS Of lIVE SPECImENS ARE dIffICUlT OR ImPOSSIblE TO dETERmINE. OVERAll, H. aethra AdUlTS APPEAR SlIgHTlY lARgER ANd mORE RObUST WITH AN OVERAll RICHER ORANgE-YEllOW TONE COmPAREd TO H. diffinis IN CORRESPONdINg SPRINg VS SUmmER bROOdS (FIgS. 3–6), ANd WITH A SlIgHTlY gREATER EXTENT Of REd SCAlINg ON THE fOREWINg APEX ANd HINdWINg ANAl mARgIN ( TAblE 2).

1 maximum width including eye.

2 males (n = 6); northern univoltine populations of H. aethra do not differ significantly from those of 1 st generation bivoltine populations.

MAXImUm HEAd WIdTH IS 8% WIdER THAN H. diffinis ( TAblE 2), ANd fOREWINg lENgTH IS 14% gREATER, i. e. 35–36% OVERAll gREATER WINg AREA THAN H. diffinis . THE COlORATION Of THE dORSAl VESTITURE Of H. aethra dIffERS IN HAVINg A STRAW-YEllOW RATHER THAN blONdE-bUff dORSOlATERAl lINE. DIAgNOSTIC dIffERENCES IN AdUlT VESTITURE ARE dIffICUlT OR ImPOSSIblE TO dISCERN IN flIgHT-WORN INdIVIdUAlS. SlIgHT dIffERENCES IN fOREWINg mARKINgS ARE AlSO EVIdENT. THE fOREWINg APEX Of H. aethra HAS A lARgER REddISH-bROWN PATCH THAT USUAllY COVERS HAlf OR mORE Of THE SCAlEd mARgINAl AREA dElImITEd bY VEINS R4 ANd R5. THE REddISH-bROWN SCAlINg Of THE HINdWINg ANAl mARgIN IS AlSO mORE EXTENSIVE, gIVINg THE HINdWINg mARgIN AN OVERAll bRIgHTER APPEARANCE. UNlIKE H. diffinis , THE fOREWINg mARgINAl bANd IS NOT NOTICEAblY THINNER IN SPRINg VERSUS SUmmER INdIVIdUAlS (COmPARE FIgS. 3–5 VERSUS FIgS. 4–6), SO SEASONAl VARIATION APPEARS TO bE lESS PRONOUNCEd IN H. aethra . THE dORSAl ANd mEdIAl VESTITURE Of THE THORAX ANd AbdOmEN dIffERS fROm H. diffinis IN bEINg A RICHER ORANgE-bROWN dORSO-lATERAllY, WITH THE dORSO-mEdIAl THORAX SlIgHTlY mORE CONTRASTINg RElATIVE TO THE OlIVE-bROWN TEgUlAE. SUmmER H. aethra SPECImENS dIffER fROm THOSE Of THE SPRINg bROOd IN bEINg SlIgHTlY lARgER ( TAblE 2), ANd WITH lESS EXTENSIVE PAlE dORSOlATERAl SETAE, THE dORSUm Of A5 IS AlSO dARKER OVERAll. NO CONSISTENT mAlE gENITAlIC dIffERENCES bETWEEN H. aethra ANd H. diffinis WERE ObSERVEd. FEmAlES dIffER STRUCTURAllY IN THE SHAPE Of THE POSTVAgINAl PlATE, WHICH APPEARS AS A ROUNdEd SqUARE IN H. aethra , (0.8–1.0X AS WIdE AS lONg) ANd NARROW IN H. diffinis (0.5–0.7X AS WIdE AS lONg), bUT lESS qUAdRATE ANd mORE Off-CENTER THAN IN H. thetis ( FIg. 12 ).

LITERATURE REfERENCES TO H. aethra ARE fEW; BARNES & MCDUNNOUgH (1910) CORRECTlY dIAgNOSEd THE TAXON (bUT AS A SUbSPECIES Of H. diffinis ). THE SPECImEN IllUSTRATEd bY HOdgES (1971) ON PlATE II, fIgURE 1 ANd THAT IllUSTRATEd bY TUTTlE (2007) ON PlATE 5, fIgURE 5 AS H. diffinis ARE bOTH H. aethra , ANd lIKElY AlSO THE SPECImEN IllUSTRATEd bY HANdfIEld (2011).

Larva. THE lARVA Of H. aethra IS dISTINCTIVE: IT IS THE ONlY NORTH AmERICAN Hemaris WITH bRIgHT REd SPIRAClES, A YEllOW PROTHORACIC COllAR ANd A PINK-PURPlE CAUdAl HORN WITH blACK APEX (FIg. 7). BY COmPARISON THE SPIRAClES Of H. diffinis ARE INVARIAblY blACK (FIg. 8), ANd YEllOW-ORANgE IN H. thetis . THE bASE Of THE CAUdAl HORN IS PINKISH-PURPlE, OCCASIONAllY YEllOW gRAdINg INTO PINKISH EdgINg (FIg. 7A), UNlIKE THE bRIgHT YEllOW bASE Of H. diffinis (FIg. 8). NEITHER THE bROWN mORPH (FIg. 8A) NOR THE bICOlOREd gREEN/dARK-bROWN mORPH fOUNd IN H. diffinis ANd thetis HAVE bEEN fOUNd IN H. aethra . THE APEX Of THE HORN IS OfTEN CURVEd SlIgHTlY CAUdAd, WHIlE THAT Of H. diffinis IS OfTEN CURVEd fORWARd ( TUTTlE 2007), bUT THIS WAS NOT A CONSISTENTlY dIAgNOSTIC TRAIT IN THE mATERIAl REAREd dURINg THIS STUdY. DESPITE THE mOdERATE bOdY Of HISTORICAl lITERATURE dESCRIbINg H. diffinis lARVAE, I COUld fINd NO ACCOUNTS ASCRIbAblE TO H. aethra lARVAE.

FIGUREs 3–4. Comparison of spring-brood adults of Hemaris diffinis (Fig. 3) and H. aethra (Fig. 4) from eastern Canada. 3a. ON: Ottawa Dist., Bells Corners, Timm Dr., 29.Apr.2010, voucher # CNCLEP 140388; 3b. ON: Lanark Co., California Rd. hydro cut, 24.May.2017, voucher # CNCLEP 140389; 3c. same data as (3a), voucher # CNCLEP 140390; 3d. same locality as (3a), 13.May.2009 DNA voucher # CNCLEP 62975. Hemaris aethra (Fig. 4): 4a. NB: Madawaska Co., Edmunston, 30.May.2006, DNA voucher # CNCLEP 41278; 4b. ON: Ottawa Dist., Dolan Hwy at Carp Ridge, 7.May.2012, DNA voucher # CNCLEP 92236; 4c. same data as (4c), DNA voucher # CNCLEP 92235; 4d. ON: Lanark Co., Bellamy Rd at hydro cut, 9.Jun.2017, voucher # CNCLEP 140384.

FIGUREs 5–6. Comparison of summer-brood adults of Hemaris diffinis (Fig. 5) and H. aethra (Fig. 6) from eastern Canada. 5a. ON: Ottawa Dist., Bells Corners, Timm Dr., 15.Jul.2016, voucher # CNCLEP 140391; 5b. ON: Lanark Co., Maberly, Old Brooke Rd., 26.Jul.2017, voucher # CNCLEP 140392; 5c. same data as (5a), voucher # CNCLEP 120070; 5d. same data as (5a), voucher # CNCLEP 140383; 6a. ON: Ottawa Dist., Dolan Hwy at Carp Ridge, ex larva on Diervilla lonicera 20.Jun.2016, emgd. 14.Jul.2016, voucher # CNCLEP 140385; 6b. same data as (6a), voucher # CNCLEP 140386; 6c. same data as (6a), voucher # CNCLEP 140387; 6d. same data as (6a), voucher # CNCLEP 140393.

FIGUREs 7–8. Comparison of H. aethra (Fig. 7) and H. diffinis (Fig. 8) larvae from Ontario, Canada. 7a. ON: Ottawa Dist., Carp Hills, June 2016, ex Diervilla lonicera ; 7b. ON: Ottawa Dist., June 1979, ex D. lonicera ; 7c. ON: Lanark Co., Almonte, June 1989, ex D. lonicera ; 7d. same data as (7a); 8a. ON: Ottawa Dist., Bells Corners, Timm Dr., August 2011, ex Lonicera tatarica; 8b. ON: Lanark Co., Christie Lake, June 2015, ex Symphoricarpos alba ; 8c. same data as (8a).

Biology. TO dATE, THE ONlY KNOWN lARVAl HOST PlANT Of H. aethra IS Diervilla lonicera , bASEd ON fOUR SEPARATE lARVAl COllECTIONS IN EASTERN ONTARIO. THE gEOgRAPHIC dISTRIbUTION Of H. aethra IS ENTIRElY WITHIN THE RANgE Of D. lonicera ( FIg. 10 ). CONVERSElY, H. aethra IS AbSENT fROm mORE XERIC HAbITATS WHERE Diervilla IS RARE OR AbSENT, bUT Symphoricarpos IS COmmON. NATIVE Lonicera SPECIES ARE mUCH lESS COmmON THAN Diervilla AT SITES WHERE H. aethra OCCURS, bUT THIS gENUS mAY AlSO SERVE AS A lARVAl HOST, AS IT dOES fOR H. diffinis . BY COmPARISON, H. diffinis lARVAE IN ONTARIO ARE mOST COmmONlY fOUNd ON S. albus , THE ONlY NATIVE SPECIES Of Symphoricarpos IN THE STUdY AREA. AN EARlY INSTAR Hemaris SUSPECTEd TO bE H. diffinis WAS AlSO fOUNd ON L. dioica (THE lARVA dIEd IN THE fIRST INSTAR). IN SOmEWHAT WEEdY HAbITATS SUCH AS Old fIEldS, PARTICUlARlY IN dRY, ROCKY SITUATIONS, lARVAE Of diffinis CAN bE RElATIVElY COmmON ON THE INTROdUCEd INVASIVE L. tatarica L. BOTH Lonicera ANd Symphoricarpos ARE COmmON HOSTS Of H. diffinis IN OTHER PARTS Of THE EASTERN RANgE ( TUTTlE 2007; WAgNER 2005); SmYTH (1900) AlSO gIVES Triosteum perfoliatum AdUlT H. aethra HAVE bEEN ObSERVEd AT flOWERS Of Vaccinium, Chichory , ANd L. tatarica.

HAlf Of THE 16 lARVAE COllECTEd IN lATE JUNE PROdUCEd AdUlTS A mONTH lATER IN lATE JUlY, WHEREAS THE REmAINdER ENTEREd PUPAl dIAPAUSE. IN CONTRAST, NONE Of THE 20 + SPRINg bROOd lARVAE Of H. diffinis ENTEREd PUPAl dIAPAUSE . IT THEREfORE APPEARS THAT THE SECONd, SUmmER gENERATION Of H. aethra IS ONlY PARTIAl IN EASTERN ONTARIO . THE gENERAllY lATER SPRINg flIgHT dATES fROm NORTHERN ANd CENTRAl ONTARIO INdICATE THAT H. aethra IS UNIVOlTINE fURTHER NORTH: NEARlY All RECORdS ARE fROm JUNE, PEAKINg IN THE lAST TWO WEEKS, ANd A fEW RECORdS EXTENdINg INTO mId-JUlY . IN SOUTHEASTERN ONTARIO , THERE IS AN EARlIER SPRINg flIgHT ANd ANOTHER flIgHT IN SUmmER, WITH EXTREmE flIgHT dATES fROm EARlY MAY TO EARlY AUgUST; mOST RECORdS ARE fROm EARlY TO lATE JUNE, ANd AgAIN fROm mId-JUlY TO EARlY AUgUST.

Habitat and Distribution. COmPAREd TO THE gENERAllY mORE XERIC SAVANNAH-lIKE HAbITATS SUCH AS Old fIEldS, AlVARS ANd bARRENS INHAbITEd bY H. diffinis , H. aethra fAVORS mORE mESIC, OPEN dECIdUOUS fOREST HAbITATS, ESPECIAllY WITH NATURAl OPENINgS ON IgNEOUS bEdROCK. THIS mAY bE INdICATIVE Of HOST PlANT REqUIREmENTS AS IT PARAllElS THE dISTRIbUTION Of Diervilla lonicera ( FIg. 10 ). IN ONTARIO H. aethra IS NOT KNOWN fROm SOUTH Of THE CANAdIAN SHIEld, A REgION UNdERlAIN bY IgNEOUS bEdROCK WITH D. lonicera lOCAllY AbUNdANT; SImIlARlY, Diervilla CAN bE A dOmINANT SUb- SHRUb IN PARTS Of THE MARITImE PROVINCES (R. WEbSTER, PERS. COmm.). Diervilla lonicera RANgES SOUTHWARd AlONg THE APPAlACHIAN mOUNTAIN CHAIN, bUT THERE IS CURRENTlY NO EVIdENCE THAT H. aethra dOES SO ( FIg. 9 ). AlTHOUgH HAbITAT PREfERENCES bETWEEN H. aethra VERSUS H. diffinis EXIST, THE TWO CAN OCCUR IN STRICT SYmPATRY WHERE HAbITAT CONdITIONS PERmIT; fOR EXAmPlE, THE CHRISTINA BAY SITE ON MANITOUlIN ISlANd ANd NEAR PAKENHAm, LANARK COUNTY, ONTARIO (APPENdIX A).

SPECImENS Of H. aethra WERE EXAmINEd fROm MANITObA , ONTARIO, QUébEC , NEW BRUNSWICK , NOVA SCOTIA, MICHIgAN ANd NEW YORK ( FIg. 9 ), ANd THE SPECIES lIKElY OCCUR THROUgHOUT THE NORTHERN GREAT LAKES REgION . THE ONlY CONfIRmEd RECORdS fOR THE UNITEd STATES ARE fOR NORTHERN NEW YORK (FRANKlIN CO.) ANd NORTHERN MICHIgAN (CHEbOYgAN CO.); HOWEVER, PHOTOgRAPHS Of WHAT IS PRObAblY THIS SPECIES INClUdE ONE fROm LAKE COUNTY , MINNESOTA ( HTTPS://WWW.INATURAlIST.ORg/ObSERVATIONS/7011536) ANd ANOTHER ON THE QUébEC/ NEW HAmPSHIRE bORdER ( HTTPS://WWW.INATURAlIST.ORg/ObSERVATIONS/7051935) . IT AlmOST CERTAINlY OCCURS THROUgHOUT NORTHERN MINNESOTA , WISCONSIN, MICHIgAN, VERmONT , MAINE ANd PERHAPS SOUTHWARd INTO THE NORTHERN APPAlACHIANS. BARNES & MCDUNNOUgH (1910) CITE SPECImENS Of “ Hemaris diffinis aethra ” fROm MAINE . DUE TO THE dIffICUlTY IN IdENTIfYINg AdUlTS fROm PHOTOgRAPHS, PARTICUlARlY lIVE INdIVIdUAlS, NEW OCCURRENCES (ESPECIAllY RANgE EXTENSIONS) SHOUld bE VERIfIEd bY PHOTOgRAPHS Of lARVAE ANd/ OR VOUCHEREd SPECImENS.

Figures

FIGURE 9. Distribution of examined specimens of H.aethra. Associated specimen data is provided in Appendix 1.

FIGURE 10. Comparison of the minimum range of H. aethra (red) and the distribution of its larval host plant, Diervilla lonicera (blue). Range of H. aethra is based on minimum shape incorporating examined specimens (Fig. 8), with unverified or potentialrecordsindicated by questionsmarks.Range of D. lonciera is basedon information inKartesZ (2015) and Canadensys Explorer (http://data2.canadensys.net).

FIGURE 12. Female genitalia of Hemaris thetis (A), H. diffinis (B) and H.aethra (C). Scale bar equals 1 mm.