The subfamily Phlaeothripinae is the largest group of the family Phlaeothripidae including 3,068 species from 376 genera worldwide (ThripsWiki, 2023;Mound, 2021). In Korea, 30 species from 20 genera have been recorded in Phlaeothripinae until now (National Institute of Biological Resources, 2019).

The genus PachyliothripsOkajima, 2006 is monobasic with Pachyliothrips zelkovaeOkajima, 2006 as the type species. The genus belongs to the Liothrips-lineage, and has some generic characteristics as follow (Okajima, 2006): fore tarsal tooth present in both sexes, forewing without duplicated cilia in macroptera, abdominal terga II to VII each with only one pair of wing retaining setae, and B1 & B2 setae on tergum IX expanded in both sexes.

During our taxonomic study on Phlaeothripidae of Korea, we found the genus Pachyliothrips for the first time in Korea. In this paper, we report a new record of P. zelkovae with morphological characteristics and photographs of adult.

Materials and Methods

Samples were collected from under bark of Zelkova serrata and preserved in 95% ethanol. Before mounting samples, samples were treated in Collecting fluid, a mixture of 9 part of 10% ethanol and 1 part of acetic acid with a drop of TritonX- 100 to spread wings. Mounting was following the method of Heming (1969). Images and measurements were taken by LEICA (CTR6 LED). Abbreviations used in the material examined in Korea are as follow: CB, Chungcheongbuk-do; GB, Gyeongsangbuk-do; GN, Gyeongsangnam-do; JB, Jeollabuk-do; JN, Jeollanam-do. Depository abbreviations are also as follow: [GNU] Department of Plant Medicine, Gyeongsang National University; [NIAS] Division of Crop Protection, National Institute of Agricultural Sciences.

Taxonomic Accounts

Subfamily Phlaeothripinae

Genus PachyliothripsOkajima, 2006

Pachyliothrips zelkovaeOkajima, 2006 느티나무관총채벌 레(신칭)

Pachyliothrips zelkovaeOkajima, 2006: 497. (Type locality: Japan)

Female (microptera). body small, body length: 2.0-2.2 mm (Fig. 1B). Uniformly dark brown; tibia and some antennal segments a little paler (Fig. 2C). Head almost as long as broad, dorsal surface reticulate (Fig. 2A). Antennae eight-segmented; segment III and IX with one (0+1) and three (1+2) sense-cones, respectively. Eyes developed, smaller on ventral surface. Maxillary stylets long without maxillary bridge, reaching eyes. Mouth-cone long and pointed, reaching mesothorax (Fig. 2B). Prothorax developed with five pairs of major setae; basantra absent; notopleural sutures complete. Fore tarsal tooth present. Wings vestigial. Metathoracic sternopleural suture present (Fig. 2D); pelta broad (Fig. 2E). Tube shorter than head (Fig. 2F).

Male (microptera). Body length 1.7-1.9mm (Fig. 1A). very similar in color and structure (Fig. 3) to female (mic).

Material Examined. All samples were collected under the bark of Zelkova serrata. [GNU] 1 female, Boeun, CB, Korea, 3. II. 2023, leg I. Han; 3 females and 7 males, Jinju, GN, Korea, 5 & 9. III. 2023, leg I. Han; 1 female, Jinju, GN, Korea, 29. III. 2023, leg I. Han; 2 females and 1 male, Jinju, GN, Korea, 11. IV. 2023, leg I. Han; 1 female and 2 males, Geoje, GN, Korea, 3. V. 2023, leg I. Han; 1 female, Jeonju, JB, Korea, 17. III. 2023, leg I. Han; 2 females, Gwangyang, JN, Korea, 7. IV. 2023, leg I. Han. [NIAS] 3 females, Cheongwon, CB, Korea, 26.II. 1999, leg G.S. Lee; 1 female and 2 males, Boeun, CB, Korea, 26.II. 1999, leg G.S. Lee; 1 female, Yeongju, GB, Korea, 24.II. 1999, leg S. Lee; 1 male, Gunwi, GB, Korea, 24.II. 1999, leg G.S. Lee; 4 females, Gyeongju, GB, Korea, 25.II. 1999, leg G.S. Lee; 3 females and 4 males, Cheongdo, GB, Korea, 25.II. 1999, leg G.S. Lee; 2 males, Muju, JB, Korea, 26.II. 1999, leg G.S. Lee.

Distribution. Korea (new record from CB, GB, GN, JB, and JN) and Japan (Honshu).

Biology. As shown in materials examined above, P. zelkovae overwinters under the bark of Zelkova serrata (Ulmaceae) in Korea as in Japan (Okajima, 2006), but its biology is almost unknown. Although it is presumed to feed on the green leaves, it is not obvious whether the species is plant-feeder or not.