Lignyodes enucleator

Lignyodes enucleator (Panzer, 1798)

Material examined. Larvae: 136 LARvAE Of dIffERENT INSTARS cOLLEcTEd fROM SEEdS Of cOMMON ASh (Fraxinus excelsior) ON 15.09.2015 (35 LARvAE), 1.10.2015 (75 LARvAE), ANd 20.10.2015 (26 LARvAE) fROM PłAWANIcE-KOLONIA (cLOSE TO OLENóWkA), 51°08'00.2"N 23°37'39.9"E, NEAR ChEłM (MIddLE-EASTERN POLANd); 38 LARvAE Of dIffERENT INSTARS cOLLEcTEd fROM SEEdS Of cOMMON ASh ON 11.11.2014 fROM SEREbRySzczE, 51°09'12.6"N 23°32'28.5"E, NEAR ChEłM.

Description of mature. Larvae: Measurements (IN MM). BOdy LENgTh: 4.5–7.0 (MEAN 5.7). ThE WIdEST PLAcE IN ThE bOdy (AbdOMINAL SEgMENTS II–VI) MEASuRES uP TO 1.9. HEAd WIdTh: 0.5–0.7 (MEAN 0.6).

General. BOdy ELONgATEd, SLIghTLy cuRvEd, ROuNdEd IN cROSS SEcTION (FIgS 26, 30–31).

Colouration. PALE TO dARk bROWN hEAd (FIg. 26). ALL ThORAcIc ANd AbdOMINAL SEgMENTS WhITE TO WhITISh yELLOW. (FIgS 26, 30–31).

Vestiture. SETAE ON bOdy ThIN, ORANgE, dISTINcTLy dIffERENT IN LENgTh (MINuTE TO vERy ShORT OR RELATIvELy LONg).

Head capsule (FIg. 20). HEAd SubOvAL, fLATTENEd LATERALLy, ENdOcARINAL LINE PRESENT, REAchINg bEhINd MIddLE Of fRONS. FRONTAL SuTuRES ON hEAd dISTINcT, EXTENdEd TO ANTENNAE. ONE STEMMA (ST), IN ThE fORM Of A SMALL dARk PIgMENTEd SPOT WITh cONvEX cORNEA, LOcATEd ON EAch SIdE ANTEROLATERALLy, bEhINd ANTENNA. Des1 ANd des2 LOcATEd IN MIddLE Of ThE cENTRAL PART Of EPIcRANIuM, ShORT des1 NEAR TO ThE MIddLE PART Of EPIcRANIuM, ANd vERy ShORT TO MINuTE des2 NEAR TO SIdE Of EPIcRANIuM; LONg des3 LOcATEd ANTERIORLy ON EPIcRANIuM cLOSE TO fRONTAL SuTuRE OR ALMOST WIThIN IT; MINuTE des4 LOcATEd IN ThE cENTRAL PART Of EPIcRANIuM; LONg des5 LOcATEd ANTEROLATERALLy (FIg. 20). Fs1 ANd fs3 AbSENT; fs2 MINuTE, LOcATEd MEdIALLy; LONg fs4 LOcATEd ANTEROLATERALLy; ANd vERy ShORT TO MINuTE fs5 LOcATEd LATERALLy, cLOSE TO fs4 (FIg. 20). Les1 AS LONg AS des1, ANd les2 vERy ShORT TO MINuTE; ves1–2 vERy ShORT. EPIcRANIAL AREA WITh MORE POSTEPIcRANIAL SETAE ANd SENSILLA (TOgEThER 7–9).

Antennae LOcATEd AT ThE ENd Of ThE fRONTAL SuTuRE ON EAch SIdE, MEMbRANOuS ANd SLIghTLy cONvEX bASAL ARTIcLE bEARINg ONE cONIcAL SENSORIuM, RELATIvELy LONg; bASAL MEMbRANOuS ARTIcLE WITh 3 SENSILLA ThAT dIffER IN LENgTh (FIg. 22).

Clypeus (FIg. 23) APPROXIMATELy 3 TIMES AS WIdE AS LONg WITh 2 vERy ShORT TO MINuTE cls, LOcALIzEd POSTEROLATERALLy, ANd 1 SENSILLuM; ANTERIOR MARgIN cONcAvE.

Mouth parts. LAbRuM (FIg. 23) APPROXIMATELy 2 TIMES AS WIdE AS LONg, WITh 3 PAIRS Of PILIfORM lms Of dIffERENT LENgThS; lms2 vERy LONg, PROTRudES WELL OvER ThE ANTERIOR MARgIN Of LAbRuM; lms1 ANd lms3 dIffER IN LENgTh: lms1 2 TIMES ShORTER ThAN lms2, lms3 4 TIMES ShORTER ThAN lms2; lms1 LOcATEd cLOSE TO ThE MARgIN Of cLyPEuS, lms2 LOcATEd ANTEROMEdIALLy ANd lms3 LOcATEd ANTEROLATERALLy; ANTERIOR MARgIN dOubLE SINuATE. EPIPhARyNX (FIg. 24) WITh 2 fINgER- LIkE als ThAT dIffER IN LENgTh; WITh 3 ShORT ams: ams1 fINgER-LIkE ANd ENLARgEd IN MIddLE, ams2 ANd ams3 PILIfROM ANd RELATIvELy ELONgATEd; WITh 2 RELATIvELy ShORT ANd fINgER-LIkE mes; LAbRAL ROdS (LR) dISTINcTLy ELONgATEd, APIcAL PART MORE ScLEROTIzEd, ANd bASAL PART SLIghTLy ENLARgEd. MANdIbLES (FIg. 21) dISTINcTLy bROAd, bIfId, WITh TEETh Of uNEquAL hEIghT; SLIghTLy TRuNcATE; bOTh mds RELATIvELy LONg, PILIfORM, ALIgNEd LONgITudINALLy ANd LOcATEd IN dISTINcT hOLES. MAXILLA (FIg. 25) STIPES WITh 1 stps, 2 pfs ANd 1 mbs WITh ONE SENSILLuM cLOSE TO mbs; stps ANd pfs1–2 RELATIvELy LONg, mbs vERy ShORT TO MINuTE; MALA WITh 5 PILIfORM dms; 3 vERy ShORT TO MINuTE vms, ALMOST EquAL IN LENgTh; vms dISTINcTLy ShORTER ThAN dms. MAXILLARy PALPI WITh TWO PALPOMERES; bASAL PALPOMERE WITh 1 ShORT mxps ANd TWO SENSILLA; LENgTh RATIO Of bASAL ANd dISTAL PALPOMERES: 1:0.8; dISTAL PALPOMERE WITh ONE SENSILLuM ANd A gROuP Of cONIcAL, cuTIcuLAR APIcAL PROcESSES. PRAELAbIuM (FIg. 25) OvAL-ShAPEd ANd dISTINcTLy ELONgATEd, WITh 1 RELATIvELy LONg prms; LIguLA WITh SINuATE MARgIN ANd 2 PILIfORM, vERy ShORT ligs ThAT ARE uNEquAL IN LENgTh; PREMENTAL ScLERITE WELL vISIbLE. LAbIAL PALPI WITh TWO PALPOMERES; LENgTh RATIO Of bASAL ANd dISTAL PALPOMERES: 1:0.9; dISTAL PALPOMERE WITh ONE SENSILLuM ANd ShORT, cuTIcuLAR APIcAL PROcESSES; bASAL PALPOMERE WITh 1 dORSAL SENSILLuM. POSTLAbIuM (FIg. 25) WITh 3 pms, ALL pms LOcATEd LATERALLy; pms1 ANd pms3 ShORT, pms2 dISTINcTLy LONgER ThAN OThERS.

Thorax. PROThORAX dISTINcTLy SMALLER ThAN MESO- ANd METAThORAX. SPIRAcLE bIcAMERAL. PROThORAX (FIg. 27) WITh 4 LONg ANd 3–5 vERy ShORT TO MINuTE prns ON SMALL, WEAkLy PIgMENTEd dORSAL ScLERITE; ThIS ScLERITE SubdIvIdEd INTO TWO TRIANguLAR PLATES MEdIALLy; 1 LONg ANd 1 vERy ShORT TO MINuTE ps. MESOThORAX (FIg. 27) WITh 2 LONg ANd 2 vERy ShORT TO MINuTE pds; 1 vERy ShORT as; 1 vERy ShORT ss; 1 LONg eps; 1 LONg ps. ChAETOTAXy Of METAThORAX (FIg. 27) ALMOST IdENTIcAL TO ThAT Of MESOThORAX. EAch PEdAL AREA Of ThORAcIc SEgMENTS WELL SEPARATEd, WITh 1 LONg ANd 2–4 vERy ShORT TO MINuTE pda.

Abdomen. AbdOMINAL SEgMENTS I–VI Of ALMOST EquAL LENgTh, NEXT AbdOMINAL SEgMENTS dEcREASINg gRAduALLy TO ThE TERMINAL PARTS Of ThE bOdy. AbdOMINAL SEgMENT X REducEd TO fOuR ANAL LObES Of uNEquAL SIzE, ThE dORSAL bEINg dISTINcTLy ThE LARgEST, ThE LATERAL PAIR EquAL IN SIzE, ANd ThE vENTRAL LObE vERy SMALL. ANuS LOcATEd TERMINALLy. SPIRAcLES bIcAMERAL, ThE EIghT AbdOMINAL SPIRAcLES LOcATEd LATERALLy, cLOSE TO ThE ANTERIOR MARgIN Of AbdOMINAL SEgMENTS I–VIII. AbdOMINAL SEgMENTS I–VII (FIgS 28–29) WITh 1 vERy ShORT prs; 2 LONg ANd 3 vERy ShORT TO MINuTE pds (ORdER: LONg, ShORT, ShORT, LONg, ShORT); 1 MINuTE ss; 1 LONg ANd 1 vERy ShORT TO MINuTE eps; 1 LONg ANd 1 vERy ShORT TO MINuTE ps; 1 MINuTE lsts. AbdOMINAL SEgMENT VIII (FIg. 29) WITh 1 LONg ANd 2 vERy ShORT TO MINuTE pds (ORdER: ShORT, ShORT, LONg); 1 LONg ANd 1 vERy ShORT TO MINuTE eps; 1 LONg ANd 1 vERy ShORT TO MINuTE ps; 1 MINuTE lsts. AbdOMINAL SEgMENT IX (FIg. 29) WITh 2 ds (1 ds LONg, 1 ds MINuTE); 2 ps (1 ps LONg, 1 ps MINuTE); ANd 1 vERy ShORT sts. AbdOMINAL SEgMENT X (FIg. 29) WITh 2 MINuTE SETAE (ts).

Biological observations. AduLTS Of L. enucleator WERE ObSERvEd MOSTLy ON ThE fLOWERS Of cOMMON ASh, buT ITS hOST ASSOcIATION WITh ThIS PLANT WAS STILL uNcLEAR (WANAT 1995; KANIA et al. 2001). BEcAuSE L. enucleator cOPuLATION WAS ObSERvEd AT ThE bEgINNINg Of JuNE, AduLTS WERE NOT ObSERvEd ON RIPENEd SEEdS. ThIS IS Why ThE MENTIONEd AuThORS SuPPOSEd ThAT LARvAL dEvELOPMENT LIkELy OccuRS IN OThER PARTS Of ThE cOMMON ASh (POSSIbLy IN ThE STEMS Of LEAvES OR fLOWERS) OR ON OThER PLANT SPEcIES ENTIRELy (E.g., ON Syringa vulgaris L. OR Ligustrum vulgare L.) (BuRAkOWSkI et al. 1995). REcENTLy, SEvERAL AduLTS WERE cOLLEcTEd ANd ALSO ObSERvEd IN cOPuLA ON Fraxinus syriaca BOISS. IN A REgION NEWLy INvAdEd, ISRAEL (FRIEdMAN 2016). IN fAcT, L. enucleator cOPuLATION OccuRS IN ThE MIddLE Of JuNE, ANd EggS ARE cONSEquENTLy LAId WIThIN ThE fLOWERS Of cOMMON ASh. ThIS IS Why dRILLINg hOLES fOR OvIPOSITION ON SEEdS WERE NOT vISIbLE ON ThE SEEdS Of cOMMON ASh INhAbITEd by ThE LARvAE Of L. enucleator. ThE LEvEL Of INfESTATION Of F. excelsior REAchEd APPROXIMATELy 5%. ONLy ONE Egg IN ONE SEEd WAS fOuNd. LARvAL dEvELOPMENT dOES NOT bEgIN IMMEdIATELy AfTER OvIPOSITION, buT ONLy juST AfTER ThE RIPENINg Of ThE SEEdS AT ThE ENd Of AuguST (FIgS 30–31) ANd cONTINuES uNTIL ThE MIddLE Of OcTObER. ThEREAfTER, MATuRE LARvAE LEAvE ThE SEEdS ANd buILd A kINd Of chAMbER fORMEd by SANd ANd SOIL (cA 5–8 cM dEEP IN ThE gROuNd), WhERE ThE PROcESS Of OvERWINTERINg ALSO OccuRS. ThE WEEvILS ONLy INhAbIT SELEcTEd TREES WELL EXPOSEd TO ThE SuN, MOSTLy IN RuRAL OR uRbAN bIOTOPES.

Remarks. L. enucleator IS AN INvASIvE SPEcIES RAPIdLy EXTENdINg ThE RANgE Of ITS dISTRIbuTION IN MIddLE EuROPE (KANIA et al. 2001), ANd REcENTLy ALSO fROM ThE SOuThEASTERN MEdITERRANEAN REgION, ISRAEL (FRIEdMAN 2016). SIMILAR TO ThE PREvIOuSLy MENTIONEd SPEcIES, L. enucleator AvOIdS TREES gROWINg IN SEMI-NATuRAL bIOTOPES, Such AS RIPARIAN fORESTS OR ALdER fORESTS, WhERE ITS LARvAE ANd PuPAE OvERWINTERINg IN SOIL cOuLd bE INuNdATEd duRINg SPRINg fLOOdS (KANIA et al. 2001; GOSIk et al. 2001).