The genus Cynaeus was originally described to type species, Platydema angustumLeConte, 1851 by LeConte (1862) and was found in the desert of the Colorado River, California. This genus belonging to the subfamily Diaperinae (Tenebrionidae), characterized by the following features: lateral sides of elytra without carinae and meso- and metatibiae with a fine crenulate ridge on outer surface (Ferrer, 1995). Cynaeus comprises only two species: C. opacusChampion, 1886 (a synonym of C. angustus) was described from Northern Sonoran in Mexico. Another member, C. depressusHorn, 1870, was described from the coastal range of California, but it has not been recorded in agricultural or urban situations (Dunkel et al., 1982).

C. angustus is found under bark and around the base of Yucca plants as a scavenger and part-time predator. Originally it was restricted to the south-west USA and north-west Mexico. However it has been spread progressively to north and east regions in the 1920s and 1930s and reached as far north as southern Canada in the 1940s (Dunkel et al., 1982). In the 1990s, it was found for the first time in Sweden of other continents (Ferrer and Andersson, 2002). In addition, it has become a pest of stored grain and is spreading in its distribution.

In this paper, we report a new stored grain pest by C. angustus (LeConte) in Korea. Morphological photographs of adult and larva, taxonomic diagnosis, and an interactive identification key to 17 tenebrionid pests detected from grain inspections of plant quarantine in Korea are provided.

Materials and Methods

Specimens for Cynaeus angustus (LeConte) were collected from corrugated cardboard traps (30×30 cm) in rice mills from Korea and are deposited in the Insect Collection of Sunchon National University. Specimens using in the interactive pictorial key are preserved in the Insect Collection of Sunchon National University (SCNU) and Animal and Plant Quarantine Agency (QIA). Many pictures of specimens displayed in the key were taken using a Leica DFC2900 digital camera and stacked using the Leica Application Suite Program (LAS Version 4.6.0; http://www.leica-microsystems.com).

The following abbreviations are used in this paper: GB, Gyeongsangbuk-do Province; GG, Gyeonggi-do Province; GN, Gyeongsannam-do Province; JB, Jeollabuk-do Province; JN, Jeollanam-do Province, Korea.

Results and Discussion

Taxonomic accounts

Family Tenebrionidae Latreille, 1802 거저리과

Subfamily Diaperinae Latreille, 1802 르위스거저리아과

Tribe Diaperini Latreille, 1802 르위스거저리족

Genus CynaeusLeConte, 1862

CynaeusLeConte, 1862: 233. [Type species: Platydema angustumLeConte, 1851]

Cynaeus angustus (LeConte, 1851) 북미쌀거저리(신칭)

Platydema angustusLeConte, 1851: 149. [Type locality: USA - California]

Cyanaeus opacusChampion, 1886: 156. [Type locality: Mexico - Northern Sonoran]

Common name. Larger black flour beetle.

Diagnosis. Adult (Fig. 1): Body elongate-oblong, almost parallel-sided, weakly convex dorsally, slightly glossy, reddish brown to blackish brown colour. Head widest at eyes from above. Eyes slightly incised by side margin of head and occupied the length of 3 or 4 facets laterally. Antennae gradually enlarged to apex. Pronotum transverse, strong microsculpture between punctures, about twice as broad as long, widest at middle, with lateral margin rounded from base to angulated anterior angles, with basal margin slightly bisinuate. Elytra with intervals flat; striae more regularly impressed. Elytral margin (pseudopleuron) obviously flattened and gradually narrowing towards tip. Meso- and metatibiae with a fine crenulate ridge on outer surface. Body length 5.0-6.0 mm.

Larva [Fig. 2; referred to Spilman (1986)]: Body elateriform; 12-15 mm long when fully grown; light brown in colour. Eye spot small and elongate. 2nd antennomere 1.6 times as long as 1st; 3rd antennomere 0.7 times as long as 1st; apical seta very long. Last abdominal tergum narrowed to a single acute apex and with a pair of short setae on each side near apex. Middle trochanter with short coarse seta apically on anterior surface near ventral border, and slightly less coarse setae at same location in posterior surface; middle femur with 2 coarse short setae on ventral surface and 1 long slender seta between, with 2 coarse short setae on distal half of posterior surface and a few slender setae on anterior surface; middle tibiotarsus with 3 coarse setae on ventral surface, 1 coarse seta at apex, 1 coarse seta at basal 1/3 on posterior surface, and a few slender setae on anterior surface; middle claw with 1 coarse seta ventrally. Hind leg same as middle, but coarse setae slightly longer.

Materials Examined. [GG] 1 adult, Hwaseong Rice Processing Complex (RPC), 6. VII. 2016; 1 adult, Yongin RPC, 12. VII. 2016; [JB] 1 adult, Iksan RPC, 20. XI. 2015; 1 larva, Iksan RPC, 6.VII. 2016; 7 adults, Namwon RPC, 6.VII. 2016; 2 adults, Gochang RPC, 18. VII. 2016; [JN] 3 adults, Naju RPC, 18. VII. 2016; [GB] 3 adults, Uiseong RPC, 21. VII. 2016; [GN] 25 adults, Ulsan RPC, 20.VII. 2016; 4 adults (1 ex. shortly after emergence), 1 larva, Jinju RPC, 12. XIII. 2015; 2 adults and 2 larvae, Jinju RPC, 16. XI. 2015; 2 larvae, Jinju RPC, 21.VII. 2016.

Distribution. Korea (new record - introduced), Germany (introduced; Reibnitz and Schawaller, 2006), Finland (introduced; Ferrer and Andersson, 2002), Sweden (introduced; Ferrer, 1995), Nearctic region.

Remarks. Recently, this species has become a pest of stored grain, and its distribution was spread into northern Europe in the 1990s. In Korea, this species is probably introduced pest because it was collected various life stages from several sites throughout the year. We guess that it was established on the grain storage condition in Korea. Due to the data (Table 1) using the PIS database (Pest Information System operated by QIA, which are accumulated interception data from 1996 to present), this species was intercepted 15 times on by-products of grains from U.S.A and China after the 2000s. Because we have no information about whether this pest is distributed in China, it should be continually to need more careful inspection of Chinese goods.

A pictorial identification key to tenebrionid pests detected during quarantine in stored products in Korea

The interactive identification key (Fig. 3) has been made to easily identify tenebrionid pests of stored grains thorough matching pictures of specific characteristic corresponding to the query. This key is composed of 18 queries for 17 tenebrionid pests including 13 species distributed in Korea and 4 exotic species, and can be easily used by warehouse managers, entomological researchers and quarantine inspectors.