Diuncus ciliatoformis (Schedl)

Beaver, R. A., Sittichaya, W. & Liu, L-Y., 2014, A Synopsis of the Scolytine Ambrosia Beetles of Thailand (Coleoptera: Curculionidae: Scolytinae), Zootaxa 3875 (1), pp. 1-82 : 44-45

84. Diuncus ciliatoformis (Schedl) *

Xyleborus ciliatoformis Schedl, 1953: 290 .

Diuncus ciliatoformis (Schedl) : Hulcr & Cognato, 2009: 32.

Thai distribution: N: Chiang Mai; S: Nakhon Sri Thammarat, Surat Thani. New to Thailand .

New records: Chiang Mai, Doi Inthanon , 5.viii.2002 (K. Koivisto) (1); Nakhon Sri Thammarat, Khao Luang NP, headquarters, 08° 22' 21.6'' N, 99° 44' 14.7'' E, 196 m, EtOH trap, 1.xii.2010 (W. Sittichaya) (1); Namtok Yong NP, 8° 10.434' N, 99° 44.508' E, 80 m, pan trap, 29–30.vii.2008 (U-prai, K.) (1); Surat Thani, Khao Sok NP, Bang Huaraed, 8° 54.555' N, 98° 30.522' E, 122 m, MT, 23–30.xii.2008 (Pongphan) (1) .

Other distribution: ‘Borneo’, Malaysia (E. & W.), Papua New Guinea, Taiwan. Intercepted in Australia and Japan in timber imported from the region. (3)

Taxonomy: Hulcr and Cognato (2013) consider this species to be a synonym of Diuncus justus (Schedl) , but we prefer to keep the two species separate ( Beaver & Liu 2010). Diuncus ciliatoformis can be distinguished from D.justus by the following characters ( D.ciliatoformis characters given first): body length 1.7–1.9 mm vs 1.4 –1.6 mm; length to width ratio 2.38–2.56 vs 2.10–2.29; pronotum more broadly rounded anteriorly, the sides subparallel in basal half, the posterior angles subrectangular, the median pair of teeth on the anterior margin usually little larger than the next outer pair vs pronotum more narrowly and angularly rounded anteriorly, the sides evenly rounded in the posterior half, the posterior angles broadly rounded, the median pair of teeth on the anterior margin distinctly larger than the next outer pair; elytral length to width ratio 1.43–1.58 vs 1.30–1.43; sutural interstriae distinctly raised on elytral declivity, elytral pubescence denser with strial hairs present on disc and declivity vs sutural interstriae not raised on declivity, elytral pubescence sparser, strial hairs absent or very short. In Brunei and Sabah, where both species occur together, they remain distinct. DNA studies of the species in this group are needed.

Biology: The species of Diuncus are mycocleptic, making use of the ambrosia fungi of other ambrosia beetles, and lack mycangia ( Hulcr & Cognato 2010b). D.ciliatoformis appears to have a preference for ambrosia beetles attacking Dipterocarpaceae ( Browne 1961a) . The gallery system is simple with a terminal brood chamber in the longitudinal plane ( Browne 1961a).

Illustrations: P (Hulcr 2013 as synonym of Diuncus justus ).