Periphyllus allogenesSzelegiewicz, 1981 is an insect pest that exclusively damages Acer triflorum and its distribution is only recorded in Korea. To date, aptera viviparous generation of P. allogenes has been described worldwide (Szelegiewicz, 1981).

The genus Periphyllus is a highly polymorphic group comprising 52 monoecious and holocyclic species worldwide; however, not all morphs of Periphyllus spp. have been identified (Blackman and Eastop, 2022;Sugimoto, 2013;Wieczorek et al., 2017). For example, fundatrix generations have only been reported in approximately 10 Periphyllus species, and alate viviparous female generations have only been reported in approximately 31 species worldwide (Blackman and Eastop 2022;Essig and Abernathy, 1952;Lubiarz and Mackoś-Iwaszko, 2015). Recently, oviparous female and alate male generations of Periphyllus koeleruteriae have been identified (Junkiert and Wieczorek, 2019). However, before 2019, only apterous viviparous females, alate viviparous females, and aestivating nymph generation of P. koeleruteriae were described (Essig and Abernathy, 1952).

Identification of unknown morphs and knowledge of their life cycle type are important for effective control measures. In this study, the fundatrix and alate viviparous generations of P. allogenes are newly described, and their distribution, host plants, and photographs are also presented.

Materials and Methods

Samples of P. allogenes were collected from Acer triflorum Kom, 1901. Samples were preserved in 95% ethanol and mounted on Canada balsam following the method described by Blackman and Eastop (2000). Images and measurements were taken using LEICA (DM3000 LED) and LEICA (CTR6 LED). Live specimens were obtained using NICON D 850. All specimens were deposited at the Institute of Agriculture and Life Sciences, Gyeongsang National University.

The following abbreviations are used for morphological features in this study: BL, body length from the head to the end of cauda; BW, body width across abdomen; Ant.I-VI, antennal segments; BD.III, basal articular diameter of Ant.III; Ant.VIb, antennal segment base of Ant.VI; PT, processus terminalis; LS Ant.III, length of the longest seta of Ant.III; LS HEAD, length of the longest seta of head; URS, Ultimate rostrum segment; HT.I, first tarsal segment of hind leg; HT.II, second tarsal segment of hind leg; HTB, Hind Tibia; FEMORA, hind femur; ABDT, abdominal tergite; ABDT.I-VI, length of the longest seta of Abdominal tergite I-VI, respectively; ABDT.VII-VIII, length of the longest seta of Abdominal tergite VII-VIII, respectively; and SIPH, Siphunculi. Following abbreviations are used for the provinces: GW, Gangwon; GG, Gyeonggi; JB, Jeonbuk; JJ, Jeonju; HC, Hongcheon; and GP, Gapyeong.

Taxonomic Accounts

Periphyllus allogenes (Szelegiewicz, 1981)(Figs. 1-3; Table 1)

Periphyllus allogenesSzelegiewicz, 1981: 37

Periphyllus triflorumiLee and Seo, 1992: 254, 262.

Fundatrix (based on three specimens) (Figs. 1, 3A; Table 1)

Colour. In life: Whole body dark, ABDT.I-III dark red; In mounted specimens: Head, Ant.III basal-middle part pale, Ant.I-III, apical part of Ant.VI, SIPH, genital plate, cauda, whole leg dark black; ABDT variably sclerites. Morphological characters. Body oval and large 2.787-3.250 mm (Fig. 1A), BW 1.689-1.955 mm; Head flat, HW 0.595-0.640 mm (Fig. 1B), dorsum head with 8-10 pairs setae, LS HEAD 0.141-0.189 mm; Antenna 1.282-1.481 mm (Fig. 1C), 0.451-0.455 × BL, 0.757-0.759 × BW, Ant.I 0.101-0.106mm with 6-9 setae, Ant.II 0.078-094 mm with 3-4 setae, Ant.III 0.434-0.529 mm with 11-15setae, Ant.IV 0.248-0.250 mm with 4-5 setae, Ant. V 0.212-0.231 mm with 1-4 setae, BASE 0.139-0.166 mm with one seta, PT 0.070-0.105 mm, Ant.VIb clearly longer than PT, PT 0.503-0.632 × BASE, LS Ant.III 0.128-0.171 mm, 3.764- 4.384 × BD.III; Whole legs pointed, long and numerous setae; FEMORA 0.675-0.779 mm; HTB 1.184-1.306 mm (Fig. 1D) with rows of spinules to apical part; HT.I 0.060-0.069 mm with first tarsal chaetotaxy 6:6:6; HT.II 0.179-0.190 mm; URS 0.129-0.142 mm (Fig. 1E), reaching middle coxae, 0.720-0.747 × HT.II with 3-4 pairs setae; ABDT variably developed spinal, pleural, and marginal sclerite part with pointed, short and numerous setae, stout and longest setae in ABDT.I-VI 0.221- 0.254 mm, ABDT.VI between with 56-71 setae; Stout and longest setae in ABDT.VII-VIII 0.228-0.265 mm; SIPH (Fig. 1F) length 0.077-0.109 mm, SIPH width 0.142-0.218 mm, SIPH width longer than SIPH length, SIPH with rows of reticulation, clearly developed whole part; Cauda width 0.183-0.233 mm (Fig. 1G), in generally rounded with 15-24 setae.

Alate viviparous female (based on six specimens) (Figs. 2, 3C; Table 1)

Colour. In life: ABDT dark red; thorax, whole leg, head and Ant.I-VI black; wing vein brown. In mounted specimens: head, whole antenna, thorax, SIPH, genital plate, cauda, whole leg dark brown; wing vein brown. Morphological characters. Body elongate and large 2.259-2.873 mm (Fig. 3A), BW 1.018 -1.306 mm; Head flat, HW 0.509-0.574 mm (Fig. 3B), dorsum head with 9-13 pairs setae, LS HEAD 0.135-0.186mm; thorax sclerotized; Antenna 1.423-1.714 mm (Fig. 3C), 0.596-0.629 × BL, 1.312-1.397 x BW, Ant.I 0.074-0.096 mm with 6-9 setae, Ant.II 0.064-0.077 mm with 3-4 setae, Ant.III 0.526-0.631 mm with 8-18 setae and 26-34 secondary rhinaria, Ant.IV 0.238- 0.303 mm with 4-8 setae and 6-10 secondary rhinaria, Ant.V 0.220-0.245 mm with 2-5 setae, Ant.VIb 0.154-0.172 mm with 1-2 setae, PT 0.147-0.190 mm, PT slightly longer than Ant. VIb, PT 0.954-1.105 × BASE, LS ANT.III 0.128-0.146 mm, 4.294-4.413 × BD.III; Whole legs pointed, long setae; FEMORA 0.628-0.771 mm; HTB 1.177-1.365 mm (Fig. 3D) with rows of spinules to apical part; HT.I 0.049-0.067 mm with first tarsal chaetotaxy 7:7:6; HT.II 0.184-0.199 mm; URS (Fig. 3E) 0.118 -0.143 mm, slightly reaching the middle coxae, 0.641-0.718 × HT.II with 2-3 pairs setae; ABDT spinal and pleural sclerite irregularly placed 1-2 pairs setae, stout and long setae in ABDT.I-VI 0.181-0.261 mm, ABDT.VI between setae with 41-54; Spinal, pleural part with numerous pointed setae, stout and long setae in ABDT.VII-VIII 0.217-0.282 mm; SIPH width 0.133-0.218 mm (Fig. 3F) longer than SIPH length 0.083-0.152 mm, 8-11 rows of reticulation, clearly developed except basal; Cauda width 0.164-0.204 mm (Fig. 3G), in generally rounded with 10-19 setae; Wing length 2.920-3.892 mm, Wing width 0.953-1.582 mm.

Specimens examined. 3 fundatrix from Acer triflorum, Coll.#220515JH37, GNU, Hongcheon-gun, GW, 15.V.2022; 5 apterous viviparous females from A. triflorum, Coll.# 210429 JH73, GNU, Jeonju-si, JB, 29.IV.2021; 5 alate viviparous females from A. triflorum, Coll.# 220515JH38, GNU, Hong cheon-gun, GW,15.V.2022; 1 alate viviparous female from A. triflorum, Coll.# 220515JH50, GNU, Gapyeong-gun, GG, 14.V.2022

Host plant. Acer triflorum Kom. (Aceraceae).

Distribution. Korea