Pulvinaria polygonata Cockerell, 1905

Tanaka, Hirotaka & Kamitani, Satoshi, 2020, Review of the Pulvinaria (Hemiptera: Coccomorpha: Coccidae) species of the Ryukyu Islands, Japan, Zootaxa 4868 (3), pp. 408-422 : 411-414

Pulvinaria polygonata Cockerell, 1905

( Fig. 2 )

Pulvinaria polygonata Cockerell, 1905: 131 ; Robinson, 1917: 10; Morrison, 1920: 184; Kawai, 1980: 152; Williams & Watson, 1990: 151; Qin & Gullan, 1992: 141; Ben-Dov, 1993: 276; Kawai, 2003: 305, 558.

Material examined. JAPAN, Okinawa Prefecture: Ishigaki Is., Ishigaki-shi, Hirakubo , on Murraya paniculata , 05.iii.2014, coll. H. Tanaka, 4 adult females mounted singly (2 EUMJ, 2 ELKU) ; Okinawa Is., Ogimi-son, Kijoka , on Citrus depressa , 6.x.2019, coll. H. Tanaka, 4 adult females mounted singly and 4 adult females on 2 slides (4 EUMJ, 4 ELKU) .

Redescription. Live appearance: adult female elongate oval, usually flat. Dorsum greyish brown with a dark brown longitudinal line in centre, without visible wax before oviposition, but with a small amount of granular or filamentous wax produced on dorsum during oviposition period. Ovisac short, about 1–2 times as long as body; posterior part of body strongly uplifted by ovisac.

Slide-mounted adult female (n=12). Body elongate oval, 2.3–3.3 mm long, 1.4–2.1 mm wide, margin with a distinct and relatively deep indentation at each stigmatic cleft; anal cleft approximately 1/5–1/7 of body length.

Dorsum. Derm membranous, dermal areolations well developed and forming a distinct polygonal pattern. Dorsal setae spiniform, frequent, scattered over entire dorsum, each 4–9 µm long with a well-developed basal socket. Preopercular pores each oval to circular, 2–4 µm in diameter, barely sclerotised and often difficult to see and count, with 6–20 present anterior to the anal plates. Tubular ducts and microducts frequent throughout, each one situated within an areolation ( Fig. 2 DA). Dorsal tubercles of normal convex type present in submarginal areas, with 1–7 between anterior stigmatic clefts, and each side with 0–2 between anterior and posterior stigmatic clefts, and 0–3 between posterior stigmatic cleft and anal cleft. Anal plates together quadrate; each plate 129–173 µm long, 68–90 µm wide, with a well-developed supporting bar, a slightly convex posterolateral margin and 3 or 4 apical setae. Ano-genital fold with 1 or 2 pairs of setae along anterior margin and 2 or 3 pairs laterally. Anal ring bearing 6 setae. Eyespots present on submarginal area.

Margin. Marginal setae with well-developed basal sockets and tips fimbriate / frayed / spatulate / split or simply pointed; each seta 14–175 µm long, each side with 15–31 setae between anterior and posterior stigmatic clefts. Stigmatic clefts distinct and rather deep, each with 3 to 6 (mostly 4 or more) stigmatic spines, longest spine 50–80 µm long, approximately 2–5 times as long as other spines.

Venter. Derm membranous. Multilocular pores each 4–8 µm wide, with 3–8 (mostly 7) loculi, present around genital opening and on medial areas of preceding 3 to 5 abdominal segments; a small group also present lateral to each metacoxa and occasionally also laterad to each mesocoxa. Spiracular pores each 3–5 µm wide, mostly each with 5 loculi, present in rather narrow bands 1–4 pores wide between margin and each spiracle; anterior bands each containing 22–54 pores, posterior bands each with 32–69 pores. Microducts scattered throughout venter. Tubular ducts of three types: type I each with large outer ductule (about 2–3 µm wide and 8–10 µm long), a stout inner ductule (about 2–3 µm wide and 10–15 µm long) and a well-developed flower-shaped terminal gland, present in posterior medial area of head, medial area of all thoracic segments and anterior abdominal segments, also in inner submarginal area extending from near anterior abdominal segments to prothoracic segments; type II tubular ducts each with a rather small outer ductule (2–3 µm wide and 5–7 µm long) and a shallow cup-shaped invagination leading to a narrower inner ductule (<1 µm wide and 15–20 µm long) with a well-developed terminal gland, mostly occurring in medial area of the posterior abdominal segments and inner submarginal area of head, thoracic and abdominal segments; type III ducts similar to type II, but each with a short, filamentous inner ductule (<1 µm wide and 1–3 µm long) and a minute terminal gland, present intermixed with type I and type II ducts in inner submarginal areas of head, thorax and abdomen and in a broad submarginal band on head, thorax and abdomen, forming an almost complete submarginal ring, but ducts on head apex scarce or absent. Posterior 3 abdominal segments each with 1 pair of long ventral setae present on the medial area. With 3 or 4 pairs of long setae present between antennae, 0–3 pairs of long setae present on area mesad of each coxa and occasionally 0–2 pairs of long setae present on medial area of thoracic and anterior abdominal segments; other setae short and fine, distributed over entire venter. Spiracles normal for the genus but each surrounded by a weak sclerotised spiracular plate; peritreme widths: anterior spiracle 39–60 µm, posterior spiracle 50–72 µm. Legs well developed, each with a completely articulated tibio-tarsal joint and an articulatory sclerosis; claw without a denticle; both claw digitules rather broad and slightly shorter than thin tarsal digitules. Hind trochanter + femur 211–338 µm long, hind tibia 138–234 µm long, and hind tarsus 90–137 µm long. Antennae each 7 or 8-segmented (mostly 8), 314–497 µm long. Labium 46–74 µm long, 75–138 µm wide.

Host-plants in Japan. Anacardiaceae : Mangifera indica ( Kawai 2003) ; Apocynaceae : Plumeria spp. ( Kawai 2003); Rutaceae : Citrus spp. ( Kawai 1980, 2003), C. depressa , Murraya paniculata ( Kawai 1980, 2003). Worldwide host-plants records of this species are given by García Morales et al. (2016).

Remarks. Pulvinaria polygonata is most similar to P. aurantii in having (i) eyespots located on the submarginal area of the dorsum, (ii) multilocular pores mostly each with 7 loculi, and (iii) in the distribution of ventral tubular ducts (type III). However, it differs from P. aurantii in usually having more than three stigmatic spines per cleft ( P. aurantii usually has three) and a darker body colour in the pre-oviposition period ( P. aurantii is relatively pale, with a yellowish-white area in the medial part of the dorsum at this stage). Pulvinaria polygonata is also similar to P. psidii in having fimbriate marginal setae, eyespots located in the submarginal area of the dorsum, and the presence of a sclerotised plate around each spiracle. However, it differs from P. psidii in having multilocular pores with mostly each 7 loculi (those of P. psidii mostly each have 10 loculi) and an undivided supporting bar underneath each anal plate (the bar in P. psidii is bifurcate). Important diagnostic morphological character states for P. polygonata plus a comparison with the type species of the genus, P. vitis , are summarised in Table 1. Pulvinaria polygonata can be separated from other Pulvinaria species distributed in Ryukyu Islands and P. vitis by condition of dermal areolation, location of eyespots, shape of marginal seta apices, Type III ventral tubular duct distribution, the number of loculi in each multilocular pore, and the number of stigmatic spines in each stigmatic cleft.

The adult female morphology of P. polygonata described here mostly agrees well with the redescription of the species by Qin & Gullan (1992). However, the present description slightly differs from that of Qin & Gullan (1992) as follows (character states of the redescription by Qin & Gullan (1992) are given in parentheses): (i) body 2.3–3.3 mm long (2.8–4.8 mm long); and (ii) preopercular pores numbering 7–20 (34–56). These morphological discrepancies might be due to regional morphological variation. Qin & Gullan (1992) wrote that the species has “two types of ventral tubular ducts”, in contrast to our description above, which records three types of ventral tubular ducts in the species; however, the three types of ventral tubular ducts are clearly separated in their illustration and their description does say that the second type of duct has 2 sizes. It therefore seems clear that they recognized three types of ventral tubular ducts in the species. Most researchers working on Coccidae only recently accepted that there are three types of ventral tubular ducts in most Pulvinaria species (C. J. Hodgson personal communication). A similar case is also found in Qin & Gullan’s (1992) descriptions and illustrations of P. psidii and P. urbicola .

Populations of Pulvinaria polygonata collected from different locations in Japan show possible morphological variation in the length of the appendages, although they have almost same body sizes. In the population collected from Ogimi-son, Okinawa Is., antennal length is 314–401 µm and hind trochanter + femur length is 211–259 µm but body length is 2.4–3.3 mm and body width is 1.4–2.1 mm; on the other hand, in the population collected from Hirakubo, Ishigaki Is., antennal length is 457–498 µm and hind trochanter + femur length is 322–338 µm but body length is 2.8–3.2 mm and body width is 1.8–2.0 mm. Probably similar morphological variations may be found in some populations in other regions of the world.

Figures

FIGURE 2. Pulvinaria polygonata Cockerell, 1905, adult female collected in Okinawa prefecture in 2019. ANT, antenna; AP, anal plate; DA, dermal areolations; DMD, dorsal microduct; DS, dorsal seta; DT, dorsal tubercle; DTD, dorsal tubular duct; LG, leg; MP, multilocular pores; MS, marginal setae; POP, preopercular pores; SDP, spiracular disc pore; SSP, stigmatic spines; VMD, ventral microduct; VTD, ventral tubular ducts of types I–III. Scale bars: 100 µm for ANT, AP, DA and LG; 50 µm for MS and SSP; 10 µm for others.