Alcidodes curvirostris Lyal, 2000

Lyal, C. H. C. & Curran, L. M., 2000, Seed-feeding beetles of the weevil tribe Mecysolobini (Insecta: Coleoptera: Curculionidae) developing in seeds of trees in the Dipterocarpaceae, Journal of Natural History 34 (9), pp. 1743-1847 : 1833-1834

Alcidodes curvirostris Lyal , n.sp.

Robust insects, lacking protruding humeral angles; length very variable, 4.25±8.31 mm (xÅ5 l6.17, m 6.38), PW 5 2.00± 3.94 mm (xÅ5 l2.99, m 3.11), HW 5 2.44±4.88 mm (xÅ5 l3.70, m 3.83) (n 5 l21, m 29) (®gures 37, 68, 88, 89).

Head. Rostrum strongly curved, longer and more slender in female (RL 5 2.06±5.13 mm, xÅ5 3.66 mm; RL/PW 5 0.93±1.34, xÅ5 1.16; RB/RD5 0.63±0.86, xÅ5 0.73; n 5 29) (®gures 88, 215) than in male (RL 5 2.19±3.59, xÅ5 2.73 mm; RL/PW 5 0.85±0.99, xÅ5 0.91; RB/RD 5 0.81±0.98, xÅ5 0.90; n 5 21) (®gures 87, 216).

Thorax. PL/PW 5 0.59±0.72 (xÅ5 l0.66, m 0.67); prothorax lacking a tubercle behind fore coxae. Elytra with interstriae smooth or with very weak granules basally, interstria 2 sometimes depressed basally, interstria 3 slightly broader on disc than interstriae 2 and 4, strial punctures narrower than interstriae, humeri with interstria 9 not projecting beyond 8 in dorsal view (®gure 37) or, in some larger specimens, just visible on angle of humerus; EL/HW5 1.06±1.23 (xÅ5 l1.14, m 1.13). Elytral pigmentation uniform; scales small, hair-like, uniform. Fore femur with ventral tooth as in ®gures 144, 178, 179, with proximal lobe virtually parallel to long axis of femur (slightly more apparent in female than in male), obtuse to broadly acuminate, central lobe at right angles to long axis of femur, distal margin with one large and several small teeth; fore tibia with ventral tooth, mid and hind tibiae lacking ventral tooth. Ventral margin of metasternum convex, not strongly divergent from elytral margin.

Abdomen. Ventrite 5 with pronounced oval depression medially in male and occupying approximately one-third the width of the segment (®gure 122), less strong in female; male with weak scale tuft either side of depression near posterior margin, these absent in female (®gure 123).

Male terminalia. As in ®gures 426±433. Tergite 7 (®gure 426) with posterior margin concave, 4±6 plectral tubercles in line on either side near posterior margin. Segment 8 as ®gure 427. Tegmen (®gures 429, 430) with parameres separate, approximately as long as width of tegminal ring. Membrane between tegmen and aedeagus extended into a pair of lobes (®gures 431, 433). Aedeagus (®gures 431±433) longer than wide, sides rounded to weakly rounded downturned apex; dorsal surface sclerotized continuously with ostiolar sclerites, these elongate and extending into endophallus; endophallus with a pair of small obscure membranous lobes apparently permanently everted, not clearly visible in all specimens.

Female terminalia. (®gures 434±436) Tergite 7 with three or four pairs of plectral tubercles, di cult to see (®gure 434). Tergite 8 with broadly rounded posterior margin; disc and median anterior margin more weakly sclerotized than other margins (®gure 435). Spiculum ventrale (®gure 436) with broad part quadrate, not as long as apodeme. Female genitalia as in ®gures 437±439; ductus seminalis arising on bursa away from junction with common oviduct; spermatheca with gland lobe bulbous (®gure 439).

Distinguishing features. The rostrum of both sexes is strongly and evenly curved (®gures 88, 89, 215, 216), more so than most other species, and certainly more so than in other species of the dipterocarpi group in which the proximal lobe of the fore femoral tooth lies along the femur (®gures 203±207). The male has a deeper and more distinct depression on ventrite 5 (®gure 122) than other members of this sub-group (®gures 110, 112, 114).

Comments. This species is apparently restricted to the seeds of Shorea species. Specimens from Shorea virescens tend to be smaller than those from other hosts (length 4.25±6.31 mm, xÅ5 5.53, cf. 5.50±8.31 mm, xÅ5 6.85). This diOEerence in size distorts some of the measurement s given above, especially those of the sexual diOEerence in the rostrum, this problem being compounded by the curvature. The specimen from Laos has a slightly narrower aedeagus compared with other specimens, but almost certainly falls within the same species. A still undescribed species has a narrower aedeagus still, although this is somewhat variable, and the apex of the proximal lobe of the fore femoral tooth is lifted slightly (other features of this species are too variable, given the small number of specimens available, to warant description at present). This species is otherwise very similar to A. curvirostris , although on average slightly larger, and is sympatric with it on some of the same hosts (one specimen was reared with the type of A. curvirostris from the seeds of S. macroptera ).

Of the recorded hosts, S. macroptera is section Mutica sect. Macroptera; S. obtusa has not been placed in a section, and all others are section Anthoshorea.

Etymology. The name is given because of the strongly curved rostrum.

Specimens examined

HOLOTYPE ,, l Malaysia, with labels:`Holo- / type’ and`’ l and`4831 / Malaysia / Selangor / Ulu Gombak / 31 January 1973 / F. R.I. / Kepong’ and`Attacks / Shorea / macroptera / seed’ on obverse and`Brit.Mus. / 1981-366’ and ` HOLOTYPE / Alcidodes / curvirostris / Lyal. 1997’ ( BMNH) .

PARATYPES: Laos: 2 ll, K. Sedone, 18 April 1965 ( BPBM); Wapi, 15/ 31 June 1967 ( IRSNB) .

Thailand: 4mm, Chaing Mai 300 m, 2 May 1974, (Beaver) ex Shorea obtusa fruit ( RAB) ; Namuang , 1, l21± 26 May 1993 (Pacholatko and Dembicky) ( ARC) ; 2 mm Soppong Pai ; 1± 8 May 1993 (Pacholatko and Dembicky) ( ARC) .

Malaysia: Peninsular Malaysia: 2 ll, 1m, Selangor: Kepong Dipterocarp Arboretum , March 1987 (Toy), reared from seeds of Shorea assamica (BMNH) .

Indonesia: Borneo: Kalimantan, Gunung Palung Nature Reserve, Cabang Panti Research Station, January± April 1991 (Curran), reared from seeds of: Shorea gratissima (10 ll, 10mm); Shorea lamellata (2 ll); Shorea virescens (11 ll, 11mm) ( BMNH, MZB, UMMZ).

Range. Laos, Thailand, Peninsular Malaysia, Borneo.

Hosts. Shorea assamica Dyer , S. gratissima (Wall. Ex Kurtz) Dyer , S. lamellata Foxw. , S. macroptera Dyer , S. obtusa Wall , S. virescens Parijs.