Natural history of the flea beetle genus Arrhenocoela ...

Ital J Zoo l , 69 83-93 (200 2)

Natural history of the flea beetle genus Arrhenocoela Foudras (Coleoptera, Chrysomelidae, Alticinae) MAURI ZIO BIONDI

GIUSEPPINA DE NARDIS

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Dipartimento di Scie nze Ambientali, Uni ve rs ity of L'Aquila,

via \Te toio, 1-67010 Coppito (AQ) (Ira l)')

INTRODUCTION

The ge nus Arrhenocoela was described by Foudras (1860), who separated it from the ge nu s CrePidodera Chevrolat, 1836 (sensu Chevrolat, 1836) "par la disposi tion du corselet qui n'offre pas de dépression transver sa le , mais en sillon profond et limité de chaqu e cote par une fossette qui n'atteint pas le bord postérieur. .. La forme du derni e r segment de l'abdome n du mal e est très-rema rquable ainsi que celle de l'hémicycle et de l'é deage". This tlea beetle genus includes the o nl)' species A . lineata CRossi, 1790) occurring mainly in the coastal areas of the Mediterranean Basin. Our stud)' regards many aspects of this genus, such as its systematic pos ition, new ecological an d biologica l info rmation and a complete description of the egg and the fjrst-instar larva.

MATERIALS A N D METHODS Adult specimens of A . linea/a living o n Erica arborea (Erica ceae) were co llected in September 1998 in Lido cli Ostia (Rome), O m a.s.l. (Latium, Ital )'} For the rearing , preservation, ancl slide pre pa ration proceclures usecl in thi s stucl ), we re fer to LeSage (1984) ancl Biondi & cl e Na rclis (998). The materia l was prese rvecl in 70% e th )'1 alcohol. Adults and larvae were clissected using a stereosco p ic microscope. For a delaile cl morphological stucly of th e anato mi ca lly minute stru crures , the Iarva e we re placed in Faure liq uicl , mountecl o n slid es, and observed w ith a transmitte d-light micro scope (Le itz, Ortholux 2: ob j. lO, 25 / 1.25) or, afte r preparation throu g h 'c riticai point drie r' ancl 'sputtering techniqu e ', analysed witb the sca nning el ectron ic microscope (SEM, Philips XL30 CP).

ABSTRACT Some taxon omical , biological and eco logical n otes for Arrbeno coela lineala are repo ned, and the systematic pos ition of the ge nus Arrbenocoela is cliscussed . The complete cl escriptions of the egg a nel the first-instar larva are also given. Line elrawings and sca nning e lectro n micrographs of particul ,lr mo rpholog ica l aspects fo r both the aclult ancl the larva are also prov id ed .

KEY \XfORDS: Co leo ptera Chrysomeliclae - Arrbenocoela linea/a - Larval morphology - Biolog)' - Taxo no my.

AKNOWLEDGEMENTS We thank Dr. Maria Giamm alteo for he r rec hnica l assista nce with the scanning e lectron microscope (SEIvI) This research was s uppo rtecl by a grant from "Ministero clell'Univers ità e clella Ri ce r ca Tec nologica e Scientifi ca " (CLUSTER-J1 ). (Rece-ived 2/uly 2001 - Accepted 9 Oclober 2001)

Abbreviati o ns usecl: ab, abdomi nal segme nt CI to X); am , a rtic u lating membrane; ch, chorion; cl, clypeus; cls, clypeolabral suture; CUla ' firs t s ubb ranc h of th e c u b itu s vein; cUl a-c u lb' c rossvein be twee n Cu la ancl Cu 11>; CUl b' seco ncl subbranch o f the cubitus vein ; l Cuc, first cubital celi ; cx, coxa; cls, digitifo rm seta; eb, egg burster; ech, ep icho ri o n ; eph, epipha rynx ; fe , femur ; fl s, filiform seta; fr, frons; ga, galea; hy, bypopharyfL'(; i, inseltion of seta ; le, lacinia ; leps, lo ng ca pitate seme; 19, ligul a; lb , long sens illum basi conicum; lp, lab ial palpus; Ir, la brum; M3, third branch of the me d ia ve in; mncl, mandible; msx, mesotbora x; mtb, microtubercle; nux, metathorax; mxp , maxillary pa lpus; oc, ocellus; Pcu, p ost-cu bitus ve in: pcla , peelunco late seta; p e, peritreme ; pf, palpifer; pie, placoid se nsillum; pm, prementum; po, p)'gopodium ; psm , post mentum ; pv, pulvillu s : px , prothorax ; py, p)'gicliul11 ; r-m , cros svein be twee n meclial ancl radia i veins; sa, se nsory appen clage: s b . s hort se ns illum basiconi c um: scps , s h o rt capi tate se ta; spo, spiracular ope ning; 5S, st)'loco nic sensillum; sst, se nsory stru cture ; st, slipes: ti , tibia ; tI', trocante!': trn , trocantin; ts. ta rsungulu s.

TAt'{ONOMIC ACCOUNTS

A rrhenocoela lineata (Ross i, 1790) (Figs 1-43)

MOIphological description oj the egg (Figs 19-21) Size: le ngth = 1.12 ± 0 .18 mm; width = 0.60 ± 005 mm (n = 40) Shape: subcylindrical. Colo ur: orange yel

84

M. mONDI, G. DE NA RDIS

Head (Figs 23-27, 42E-I)

Hypogna th ous, subglobose , srro ngly scle rified (Fig. 23). Cephalic su tures compie re and c1early disrincr ; en docarina straig hr, black, posterio rly fused with the coro na i suture ; coronai suture shorr and thin alo ng the ep i crani a l suture inne r margino Frontal sutu res Y-shapecl , pale . Epistomal suture well sclerified form ing with the endoca rina a unique blackish T-s hapeel suture. Antennae ( Fi g. 24) one-segmented, sup porred by a well-devel oped translucid articulation membrane. Anren nomere cylinelrical, wirh strongly sclerified annu lar ring with five sensorial pores (two dorsal and three ventral); uppe r siele membranose , with a big conical sensory pa pilla basa lly slightly raised , with nine bas iconic sens illa different in shape and size; three long basi con ic sensilla (cf Ritcey & McIver, 1990; Bartler et aL, 1999) of which rwo longer, more rhin, distall y poi nred , slig htly cu rved ; one peg-like se nsilla , finge r-shapeel ; six sho rt basiconic sensiIla of which three lo nger, cone-shaped , ra ised fro m bul bous base, and three very small , denriform.

Figs 1-8 - A nhenocoela lineata, adult. l - Head, d o rsa l v iew (73x) 2 - Ditto, ventral vi ew (67x). 3 - Pronotum C66x). 4 - SC lI tellum C478x) 5 - Prosternllm (64x). 6 - Meso notum (60x). 7 Mesos ternum C53x). 8 - Pygidillm d' C73x).

low when laid; later, brown yellow, or reddish yellow . Surface : epichorion mgose, densely covered with sma ll proruberances; chorion translu cid , wi thout evide nr reti cu lation. MOlphoLogical description ol the first-instar Larva

Th e larva of A. Lineata was first described by Pe rris 0873, 1876) For those times , the description su pplied by the French autho r, based on mature larva e ["Lo ng . 6 milI. " (Penis, 1876: 198)), can be cons id ereel a goocl one. However, it is scarcely useful be cause prac tically lacki ng in precise references to the chaetotaxy and the distribu tion o f tube rcl es. We therefore believe it neces sary [O report a comple te and up-ro-elate re-description o f the first -instar larva of this species. Size: body length = 1. 27 ± O15 mm; pronota l width = 0.37 ± 0.03 mm (n = 30) Habitus: subcylindrical, thick set, gradually narrowed fro m the head to the pygidium (Fig. 22) Co lour body lemon yel low with bla ckis h cephal ic capsule , pronotum, tubercles, legs and pygi dium . Distribution anel nomencl ature of rhe tubercles is reporred in Table II.

Figs 9-16 - Arrhenocoela linea/a, ad llit. 9 - Front leg d' C35x) . lO Tarsal c1a w of the fro nt leg C282x) 11-12 - Metafe m o ral spring, anterior and posterior view (J51x). 13 - Dorsal view o f the me dian lobe of the aedeag us C54x). 14 - Ditto, ven tra l view of the distai part C203x). 15 - Ditto, dorsal vie w o f the dista i part C200x) 16 - Dino, lateral view C54x)

85

THE GENUS ARRHENOCOELA

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ly with two pairs of filiform setae; ventral membranose area with eight groups bf campaniform sensilla, symme trically arrangeel laterally to the ventral sagittal axis. Mandibles (Fig 42F, G) strongly sclerifieel, reeldish brown, ventrally concave and elorsally with two setae ancl two sensorial pores, five-dentate; tooth I reclucecl, vely short; tooth III serrate; tooth V shorter than IV Mo la not present. No ialine process along the inner basaI margino Stipes subcylindrical, thickset, partially strongly sclerified, with one pair of sensoriaI pores and six pairs of setae elifferent in shape and in size, MaxilJary articula tion membrane translucido Cardo triangular, strongly sclerified with two lateral filiform setae. Palpiferi ellypti cal, with two long setae. Maxillary palpi (Figs 26-27, 42E) three-segmented; segments 1-2 subcylindrical, seg ment 3 elongate, stumped, with the apical part membra nose, with ten smaJl cone-shaped sensorial structures: nine arrangecl in a circle and one centraI (similar to the short basiconic sensilla III type of Ritcey & McIver, 1990, but not arising from a raised bulbous base). BasaI seg ment with two senso riaI pores; middle segment with one sensorial pore and two setae; apical segment with one large placoid sensillum, one lateral external long ba siconic sensillum anel one lateral inner small seta. Galea (Fig. 42E) lobate, ventrally supported by a subrectangu-

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Fig. 17 - Arrhenocoela lineata. A, spermatheca, dorsal view. B, ditto, inner laleral view. C, ovopositor slyli, ventral view. D, ditto, dorsal view.

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Epicranium posteriorly with four pairs of minute tri choid sensilla anel two pairs of sensorial pores; elorsally with four pairs of filiform setae, one pair of small setae, two pairs of sensorial pores anel one pair of cupuliform ocelli in postero-lateral position to the antennae; latero ventrally with four pairs of filiform setae and one pair of sensorial pores; posterior epicranial margin arcuate. Frons wiele, subpentagonal with six filiform setae, of which the centraI ones much shorter anel thin, and two sensorial pores in proximal position. Clypeus (Fig. 42H) transverse, trapezoielal, laterally rounded especially at the basaI haLf. Anteclypeus scleri fteel, mediaUy weakly inciseel, with eight trichoid sensil la; postclypeus membranose with distaI margin straight. Labrum (Fig, 42H) strongly sclerified, subtriangular, with four filiform setae and two sensorial pores; distaI margin meelially weakly incised. Epiphaly~,{ (Fig. 420 rectangu[ar, in the middle elensely covered by microtricha (styloconic sensiLia sensu Bartlet et al., 1999); dorsal side laterally with five pairs of robust pedunculate setae, weakly uncinate; elistal margin dorsal

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86

M. BIO

DI, G. D E NARDIS

Figs 19-26 - Arrbenocoela linea/a. Egg: 19 - Egg with the exit ha le (h) of the new-born larva. 20 - ditto, delai!. 21 - Ep icho rion. First-in sta r la rva: 22 - HabiLus, late r:tI view. 23 - I1ead , lale ral view . 24 - L\: ft antenna , dorsal view. 25 - Ocellus. 26 - Maxillae and labium, ven tro-Ia teral view

87

THE GENUS ARRHENOCOB.A

T ABLE

I - M01phological differences between the genera Arrhenocoela and Altica.

Genu s Arrhenocoela

Genus Altica

AD ULT

ADULT

- Procoxal cavities closecl (Fig. 5)

- Hind win g ve nation with an evident CUla' linkecl to the CU1b

by a short crossvei n (CLllo-CUIl,) (G alerucinae type) (Fig. 18A) - The Pcu ve in directly assoc iated with the CUlb to form the 1Cuc; - Pcu disa ppears after assoc iating with the CUlb (Fig. 18A) - Elytral punctation arranged in regular rows - Metafemora l s pring attributable to the Blepharida Morpho-GroliP (Figs 11-12) (cf. Furth , 1985)

- Procoxal cavities partially ope n

_ Hind wing venation without CUl a (A lticinae type)

FIRST-IN STAR LARVA

FIRST-INSTAR lARVA

- Ante nna e l -seg me nted (Fig. 24)

- Tllberc1es Dai e Dpi se parated (cf. Table 11)

- Tllbercles Dm of the abdomen present (cf. TabJe II)

- Tllbercles Dpe with 1 long seta (cf. Tab le II)

- Annlllifo rm tllbe rcl es witll accesso rial rooms (Figs 41C-E)

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lar sclerite with seven setae along the apical margin anel two basiconic sensilla, peg-shaped , in the middle area. Lacinia membranose, with robust setae gathe red behind the ga lea. Prementum me mbra nose, supported by a narrow semicircul a r sclerite bearing two filiform setae a nel two sho rt basiconic sensilla . Ligula narrow and convex, with five pairs of small setae. Labial palpi two segmented; segment 1 subcylindrica l with one sensorial pore; segments 2 w ith o ne placoid sensillum, one long basiconic sensillum and six-seven apica l cone-shapecl sensorial stru ctures si mil arly to segment 3 of maxillary palpi. Postmemum shorr , sclerified with four fiJiform se tae and four sensorial pores. Hypopha rynx with rugose surface, covered with sensorial laminate structures simi lar to an indented fan. 7horax (Figs 28-34, 41C, 41 F, 41H, 42A-D) Segments subcylindrica l. Prothorax slightly larger. Pro notum eJlyptical with nine pairs of setae different in length, seven pairs of minute trichoid sensiU a and two three pairs of sensorial pores. Med ian ecdysial line pale dividing the pronotal p late imo two symmetrical parts, each with two groups of setae, o ne anterior constitutecl by six filiform setae apically poimed and another by three long club-shaped setae. Mesonotllm and me tanotum with simil ar distribution to tllbercles. Ruptor ov i blackish, dentiform , in ce ntrai position near the capitate seta of tubercl e Dlpi (Fig . 30) (cf. Tabl e II). Mesothoracic sp iracle annuliform with darker circular peritreme (F igs 29, 41C). Legs (Figs 28 , 42A-D) robust, mod e rately elongate. Metathoracic legs larger and lo nger. Legs partially me m branose, six-segmented with trochant in, coxa , trochan ter, l'emur, tibia , tarsu ngulus and pulvillus. Coxa circular, normally w ith four robust filiform setae distinctly poin

- The Pcu vein completely fll sed w ith the Cll1b to become

indistinguishable from the latter - Elytral punctatiou confused - Metafemoral spring attributable [O che Altica Morph o-Group (cf Furth, 1985)

Anteuna e 2-segmemed Tubercles Dai e Dpi united Tllbercles Dm of che a bclomen absent Tubercles Ope with 2 lo ng setae Annllliform spi racles simple

ted and ten minute spiniform sensilla. Trochanter stron gly sclerified , narrow, subcircular, with seven-e ight sen sorial pores; membranose area between trochanter and femur with four robust filiform seta e of w hich the ven traI one very long and pointed . Femur strongly scleri fied with five setae of which four along th e distaI mar gin; membranose ventral area between femur and ti bia with two long anel robust pointed seta e; tibi a lo nge r than l'emur, with five setae and one sensorial pore in elorsal-apical position. Tarsungullis (Fig. 32) stro ngly curveel anel uncinate, with one long and weakly arcuate basiconic sensillum. Abdomen CFigs 35-40, 41D-E, 41G, 43A-C)

Segments I-VII similar in chaetotaxy and tube rcle d is position but different in size; dorsa lly with two main rows of tubercles Dm (cf. Table II). Intersegmental arti culation membrane constitutecl by many transverse and tiule cleep folds and densely covered by subtriangular and imbricate microtubercles, apically posteriorly ben t. Segment VIII with posterior dorsal tu bercles fllsed along a median line (cf. Table II) ; spiracles constituted by an atriul11 wi th cirClllar transversal section generally sur rounded by nine accessoria I chambers C'air tubes', cf. Booth et al , 1990) regularly distributed along the peri mete I' Cannular multiforus spiracle) (Fig 41D, E) Pygidium (Fig. 43A) eJliptical, well sclerified in the dorsal centraI area ; dorsal setae capitate of which eight very long, placed along the external margin, and two prox ima l very short; ventral side more membranose with a subrectangular tubercle supplied with four long filiform setae and two minute trichoid sensilla. Pygopo dium (Fig. 43B) cylindrical, partially membranose, with a ventral sclerified area with two filil'orm setae, si.,'\( mi crosetae and four trichoid sensilla.

88

M. BIONDI, G. DE NARDIS

Figs 27-34 - Arrhenocoela linea/a, first-instar larva. 27 - Maxi ll ary and labial pa lpi, detail. 28 - ventro-lateral view, legs of diffe rent size. 29 - Mesothoracic spiracle. 30 - Lefr egg- burster, dorsal view. 31 - Right meta thoracic leg, front view. 32 - Metathoracic tarsungulus, front view. 33 - tarsungu lus and pulvillus of th e metat hora cic leg, lateral view 34 - Pulvillus of the metatb oracic Jeg, posterior view.


89

Figs 35-40 - Arrbenocoela lineata, first-Ìl1star larva. 35 - TerminaI part of tl1e abdomen , latera l view. 36 - Abclominal segmenr V, setae on the tubercles Dai ancl Dm, lareral view. 37 - Abclominal segmenr VI, capitate sera on the tubercle Dae. 38 - Abclominal segment V, ca pitare seta in transversal secrion. 39 - Abclominal segment VI, cligiriform se ra on the tubercle D m . 40 - Abdom inal segments VII , VIII and IX (pygiclium), dorsa l view (for abbrevia tio ns of the tubercles see Table II).

DISCUSSION

Particu!arly interesting is the shape of the larva l dorsal setae in A. lineetta obta inecl with SEM. They show, from the thorax to the pygidium, a gradua! increase of the capi tate shape with distaI part distinctly bulbous CFigs 35-38). Similar setae were described by Boving (1929)

for some species of Galerucinae. This author distingui shed 'clava te' and 'capitate ' setae according to a nar rower or larger ap ica l part. However, the morphology of most of the dorsal setae in A. lineata is very partiCll lar. They show a cylindrical shape in almost a11 their length , while the apical part is similar to a sma ll mem branose bulb, translucid an d weakly sclerifi ed. In tran

90

M. BlONDI, G. DE NARDIS

TABLE II A. lineata.

- Distribution 01 tbe tubercles in tbe lirst-insta r larva 01 OR

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C",","m~ Regio ns of tbe body: 1, protborax; 2, mesorbo rax; 3, rnetatho rax; I X, abdominal segments; DR, dorsal reg io n; DLR, dors o-Iatera l re g ion; EPR, epipleural region; PR, pleu ral region; SR, stern al region. Tubercle nomencl ature ancl abbreviations: D-DL-EPa , dorsa l, cl or so-Iate ral ancl e pipleurai ante rior fuse d; Da , dOl'sal anteri or (Dai fus ed on rnesot borax); Oae , dorsal antero-exteri or; Da i, dorsal an tero-i nterior; OLae , do rso-Iateral antero-exte rio r; OLe, clo rso-Iateral exte rior; OLp, clo rso-Iare ra l p os teri o r; OLp-S, clorso-Iatera l poste ri or anel spiracula r fu sed; Dm, dorsa l median (scural tubercle) ; Op , dorsal p osterio r (clorsa l postero-inte rio r and dorsal poste ro exterior fu sed on VIU); Dpi , clo rsal p os tero-interior; Ope, do rsal postero-exte ri or; Dp e-DLpi, clorsal pos tero-exteri or and clorso-la teral poste ro-inte rior fused); EP, e p ip leural; EPa , e piple ural ante rior; EPp, e pipleural posterior; ES, eusternal; ES-SS , euste rnal anel stern e ll ar fu secl ; P, pleura l; PST, presternal, S, spiracu lar; SS, ste r nellar: T, trocantin .

sversal sectio n, these setae show centrally a longitudinal channel ru nning from the base to the bulb o Probably, the bu lb co ntai ns urtica ting liquid; the surface of the bulb seems smooth and without po res. Tbe prox imal setae of the prono tal plate and the setae on the tu be r cles Dm are more properly c1avate-digitiform.

The SEM morph ological study also allo wed us to cla rify th e morphology of the pulvillus and the tarsungulu s (Figs 32-34). The pulvillus is constituted by a flexible, w ide and plea ted membrane, inserte d between the pos te rio r side of the tarsungulu s and the ti bia; in d o rsal view , it appears as a he mispheric hood p rote cting th e tarsung ulu s below . The pulvillus is asymme tricaJly in serted o n the distai part of the legs. Therefore , the tar sungulus is anterio rly completely uncovered consenting the larva to ca tch at the pl a nt without impedime nts from the pro tectio n membrane . This species generally lives in the coastal areas of the Mediterranea n Basin (cf. Gruev & D6 berl , 1997) ; some times it ca n penetrate inne r regio ns fo ll owing the ma q uis vegetatio n . It is assoc iated w ith Ericaceae; the ad ults mate fro m Septembe r to Nove mber; the la rval developme nt is in spring; th e p upa tion is in th e soi\. Females lay their eggs o n p lants of Erica a rborea and E. scopa ria , mainly in the bifurcations of young termi nai branches or on the leaves. The eggs, always singly laid , are almost compl e te ly co ve re d by vege taI frag me nts assuming a cryptic aspect. At the beginning, the colo ration of the egg is orange yello w then, wh en it be comes l'ipe, red dish brown. The larva comes o ut from the egg thro ug b the part of the chorion in contact with the plant, using a sma ll ho le made with the mandibles in sub-ap ical positio n. In laboratory, the incubatio n pe riod is very lo ng, about 2.5 mo nths. Ve ry probably this species spends the w inter as an egg. The first-instar larva shows an aposematic lemo n ye l low colo ration , with cepha lic capsule, pygid ium and tu bercles smooth black, which contrasts strongly w ith the green leaves, the reddish brown branches, and the white (E. arborea) or greenish flowers (E. scoparia) of Erica. From laborato lY observations, it emerged that the lar va penetrates into fl owers through a small circular hole made in the corolla and feeds o n covering tiss ue of the ovary and the immature ovules (Fig 41A, B). No first-in star larva was o bserv.ed to feed on foliar pare nchyma or fl oral coroll a.

The systematic position al the genus Arrhenocoela Some authors have co nside red Arrhenocoela closety related to NeocrePidodera He ike rtinger, 1911 (= Asiore stia J acobso n, 1925 (cf. Ko nsta ntinov & Vandeberg, 1996); = CrePidodera Chevrolat, 1836 se nsu Foudras, 1860], mainly fo r its having an evid e nt pronotal tra n sve rse antebasal sul cus laterally delimited and the e ly trai punctatio n arranged in regul ar rows. Heik e rtin ge r (1950) also incl udecl Arrhenocoela within hi s " CrePidodera- Ve rwa nclschaft", taxo no mical grou p comprehencling some Holarctic and Orie ntai ge nera characterised by: ante nnae l1-segmented; pro no tum normally with a tra nsverse antebasa l sulcus laterally clelimited ; elytral punctation arranged in regular rows; procoxal cavities generally posteriorly closed ; tibiae un modified.

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Fig. 41 - Arrhenocoela lineata, first-instar larva. A, first-instar larva in the flower of Erica arborea. B, first-instar feeding in the ovary. C, mesothoracic spiracle. D, abdominal spiracle, segments I-VII. E, abdominal spiracle, segment VIII. F, meso- and metathorax, dorsal view. G, abdominal segments VI-VIII, dorsal view. H, left side of the prothorax, dorsal view.

More recently, other authors (cf. Doguet, 1994) ha ve consiclerecl Arrbenocoela closely relatecl to the genus Altica Geoffroy, 1762. This hypothetical affinity is basecl on the following characteristics: larvae ectophagous in both genera; similar shape of the meclian lobe of aeclea gus ancl, especially, of the spermatheca; host plants re presentecl exclusively (Arrbenocoela) or partially (Alti ca) by Ericaceae. On the basis of some characters of Galerucine type hinclwing venation (Fig. 18A), such as: the presence of CUla (associateci with CUlb); the presence of the cros svein cUla-culb; the Pcu clirectly associatecl with CUlb to form the 1Cuc (cf. Suzuki, 1994), the genus Arrhenocoe la can be consiclerecl a taxon of ancient origino Howe ver, on the basis of some morphological characters mainly regarcling the particuJar shape of the meclian 10 be of aedeagl.ls (Figs 13-16) and abclomen in male (Fig.

8), spermatheca (Fig. 18A, B), ovopositor styli (Fig. 17C, D) ancl spiculum ventraJe (Figs 18A, D) in femaJes, this Mecliterranean genus shows evolutionary novelties that make more problema tic the interpretation of its syste matic position within the Western PaJearctic flea beetle fauna. Our comparative morphoJogical stucly revealecl that Arrbenocoela occupies a rather isoJatecl position, with respect to the other flea beetle genera occurring in the western Palaearctic Region. In our opinion, the affinities of Arrbenocoela must be Jookecl for in some genera from the Orientai Region (see below). With regard to the relationship between An-benocoela ancl Neocrepidodera, these two flea beetJe genera show a different metafemoraJ spring morphology. In fact, Neo crePidodera has a metafemoraJ spring with an evident 'recurve flange', a characteristic not present in Arrbeno

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YPV Fig. 42 - Arrhenocoela lineata, first instar larva. A-D, mesothoracic leg, posterior, front, dorsal and ventral view. E, right maxilla, inner lateral view. F, G, right mandible, dorsal and ventral view. H, clypeus ancl labrum, c10rsal view; I, epipharynx, inner view.

92

M. BIONDI, G. DE NARDIS

In ou r opini on, Arrhenocoela is more closely related to the Xuthea Baly, 1865, flea beetle genus widespread with lO species mainly in the Orientai Regio n a ne! asso ciated with Urticaceae (Se n Gupta & Basu, 1977; Sche rer, 1983; Mee!vee!ev, 1997) This affinity is based on the following sharee! morphological characters: procoxal cav ities posteriorly closed (Fig. 5); tarsal claws a ppenclicu late (Fig. lO); anterior intercoxal process apically clearly widened (Fig. 5); pronotal sulcu s laterally delimited (by short longitudinal furrows not reaching the pronotal base in Arrhenocoela; by long longi tuclinal furrows reaching the pronotal base in Xuthea; prono ta l base sinous (Fig. 3); frontal tuberc1es subrriangular, well delimited (Fig. I); maxillary palpi with segment 4 elongate and the seg ment 3 not enlargee!, about of the sa me len gth as seg ment 2 (Fig. 2); e lytral pun cta ti o n arranged in regular rows; metafemoral spring of the 'Btepharida morpholog ica l-group ' (Fu rth & Suzuki, 1998) (Figs 11 -12); similar hindwing ve natio n , with evident Cu la and crossve in cUl a-culb (Fig. 18A). Unfortunate ly, no info rmatio n aboLlt the morph ology of the larval stages of the genus Xuthea is yet avai lable.

l ! o;

REFERENCES B

Fig. 43 - Arrhenocoela lineata, first-instar larva. A , a bclo minal seg ments VIII ancl IX (pygicliu m) , clorsal view. B, pygopoclium , ven trai view. C , abclominal segmems VIIl , IX ,lncl X, latero-ve mral view.

coeta (Figs 11-12) (cf. Furth, 1985) Moreover, with re spect to A rrhenocoela, the genus NeocrePidodera shows: the longitudinal furrows on pronotum long and reaching the pronotal base; the frontal tubercles not di stinctly delimited and the hindwing venation more sim plified with absence of CU]a- Among the gene ra near Neo c rePidode ra, the nerva ture CU 1a is only sometimes very weakly visible in CrePidodera Chevrolat, 1836 ( = Chalcoides Foudra s, 1860) Oolivet, 1959; personal data). Some cha racters present in Arrhenocoela, such as the similar hine!wing venation (Fig. 18A) , the transverse an tebasal prono tal sulcus late rally delimited (Fig. 3), the procoxal caviries posteriorly closed (Fig. 5) and the ely traI punctation arrangee! in regular rows, are shared with the genus Afrorestia Bechyné , 1959 occurring in the Afrotropical Region . However, also in this case Afro restia has a different metafemoral spring with an evi dent 'recurve flange' (pe rs. data). Concerning the supposed affinity of Arrhenocoela to Altica, we think that many significant diffe rences ex isting between these two genera both in the adult ane! in the larva (see Table I) allow them to be consid erecl pbylogenetically distant and the sharee! ecologica I simi larities su cb as convergences, to be eva luated.

Banlet E , Romani R.. Williams I. H., Is icl oro N., 1999 - Functional a na tomy of se nsory structures o f th e a mennae of Psy//iodes chrysocephala L. (Co leoplera: Chryso melicla e ). 1m. ). Insect Morphol. Embryo l. , 28: 291-300. Bio ncli M. , De Narclis G ., 1998 - Descrizione clella la rva cii primo staclio cii Longltarsus minimus e L pratensis (Co leoptera, Chry some liclae). Fragm. Ento mo l. , 20: 1-11. Booth R. G. , Cox M L. , Maclge R. B., 1990 - Guicles to insects of impo rtance to ma n, 3. Coleoptera . C. A. B. Imernat iona l, Wal lingforcl, Oxon, 384 pp. Bov ing A. G, 1929 - Beelle larvae o f lhe s ubfa mily Ga lerucime. Proe. U S. natI. Mus. , 75: 1-49 Chevrolat L. , 1836 - In: P E. Dejean (ecl ), Ca talogue des coléoptères cl e la collection cle M. le comte Dejean, 2ncl ecl . Pa ris, Livr. 5, 443 pp. Doguet S., 1994 - Faune cle France, 80. Coléoptères, Chrysomeli cl ae . Volume 2: Alticinae. Féclération Française cles Sociétés cle Scie nces naturell es, Paris, 681 pp. Fouclras c. , 1860 - Altisicles. In: E. Mulsant (ecl.), His toi re naturel le cles co léoptères cle France. Magnin, Blancha rcl e t (ie, Paris, 384 pp. Furth D . G. , 1985 - Relationships of Palearcti c ancJ Neartic genera of Alticina e. Entomography, 3: 375-392 Furth D. G., Suzuki K , 1998 - Stuclies o f Orie ntai anel Au str:dia n Alti cinae genera basecl o n the compa rative morph o logy o f the me tafemoral spr ing, genitalia , ancl hincl wing ve na tio n. In: M. Bi o ndi, M. Da cco rcli & D. G . Furth (ecls), Proceeclings of the FOLlIth inte rnariona l Symposium o n the Chrysomeliclae, Procee clings of XX l. C.E. Firenze, ] 996. Museo Regio nale cii Scienze Naturali, Torino, pp 91 -124. Gruev B., Dbberl M., ] 997 - Ge nerai distributi o n of the fl ea bee tles in the Palaearctic s ubregion CCo leoptera, Chrysome licl ae: Alticinae). Scopolia, 37: 1-496 f-1 e ike rtinger F , 1950 - Bestimmungstabe llen europaisc he r Kiifer. LXXXII. Fam . Chrysomelicl ae. 5. Subfam. Hal ticinae. 2. Gatr. Crepidodera- Verwan clscha ft weites ten Sin nes . Koleop tero l Runclsch., 31: 15-139 Jolivet P. , 1959 - Recherc hes s ur l'aile des Chrysom eloicl ea (Co leoptera). Deuxième Pa rtie. Mé m. lnst. R. Sci. nar. Belg. Sér. 2, 58: 1-] 52; pls. XXI-XL

THE GENUS ARlU-IENOCOELA

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LeSage L., 1984 - Immature stages o f Ca naclian Neoch lam isus Kar ren (Coleopte ra : Chryso meliclae) . Can. Ento mo!., 11 6: 383-409. Medveclev L. N., 1997 - A new subgenus