Maacoccus piperis (Green)

Joshi, Sunil, Gupta, Ankita, Shashank, P. R., Pai, Sachin G., Mohan, M., Rachana, R. R., Dubey, Vinod Kumar, Sandeep, Angalakuditi & Deepthy, K. B., 2022, Recent adventive soft scale insects (Hemiptera: Coccomorpha: Coccidae) and mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) in India, Zootaxa 5194 (2), pp. 213-232 : 216-217

Maacoccus piperis (Green)

Lecanium piperis Green 1896: 10 ; Fernald 1903: 173; Varshney 1985: 26; Tang 1991: 113.

Material examined: INDIA, Karnataka, Bengaluru, Hosakote, N 13.0693°, E 77.7982°, on Piper nigrum L. ( Piperaceae ), 27.xi.2013, B. Manjunath coll., 2 ♀♀.

Appearance in life ( Fig. 1a ): Body bright reddish yellow to reddish brown, dorsal ridges and margin darker or even paler in some individuals; a few irregular dark brown radiating lines or chains of spots more or less distinct in different individuals. Dorsal surface covered with a thin transparent waxy or glassy coating. Eyes black, prominent, distinctly defined. Body broadly oval, moderately convex, broadest across median area and roughly pointed on front and back, with sharply defined median longitudinal and two transverse ridges, the median ridge touching the margin in front and terminating at the anal aperture, the anterior transverse ridge meeting the margin between anterior and posterior stigmatic clefts, posterior ridge extending to a point about midway between the posterior stigmatic cleft and the anal cleft.

Diagnosis of slide-mounted adult female (n=2) ( Fig. 2 ): Body 4.0–5.0 mm long, 3.0– 3.5 mm wide, oval to asymmetrical, broadest at level of mesothoracic legs ( Fig. 2a ); stigmatic clefts small but deep and distinct; anal cleft shallow, 750 µm long, about 1/7 th of body length.

Margin. Marginal setae each 21–25 µm long, curved posteriorly, broadening apically, sickle shaped, and serrated on outer margin ( Fig. 2b ); with 27–32 setae on each side between anterior and posterior stigmatic clefts, 80–90 setae between posterior stigmatic cleft and anal cleft, and 100–110 setae anteriorly between anterior stigmatic clefts. Stigmatic clefts each containing 9 to 13 stigmatic setae ( Fig. 2c ), each seta with rather parallel sides, bluntly pointed and slightly swollen at proximal end; median seta longest, 32–45 µm long, lateral setae (which all curve away from median seta) each 25-35 µm long. Stigmatic cleft deep, with highly sclerotized inner margin. Anal cleft with sides either closely adpressed but not fused, or slightly divergent ( Fig. 2d ). Eyespots situated on dorsum, each approximately dorsad to a point just posterior to antennal base; each lens 30–37 µm wide, situated in pale area 70–75 µm wide.

Dorsum. Derm highly sclerotized throughout at maturity, with fine reticulation ( Fig. 2e ) throughout; marginal and submarginal bands formed by pattern of lighter spots on the darker area and dark spots on the lighter area ( Fig. 2a ); median area relatively lighter, with randomly distributed small irregular dark patches; transverse ridges conspicuous by being completely colourless. Setae each shorter than width of basal socket ( Fig. 2f ) (could not be measured because of upright position), with bluntly rounded apex, frequent throughout but most abundant on submarginal areas. Pores not detected. Preopercular pores each oval to circular ( Fig. 2g ), 2.5–5.0 µm long, slightly convex, each situated on pale dermal area 12–15 µm in diameter, arranged in 3 groups on each side, forming 2 divergent lines extending anteriorly from anal plates to the abdominal segment I; first group with 63–75, second with 55–62 and third with 2–6 pores on each side. Tubular ducts absent. Submarginal tubercles absent. Anal plates together rather pyriform, with external margins convex ( Fig. 2d ); each plate with anterolateral margin considerably longer than posterolateral margin, outer angle rounded and apex with 4 setae: 1 present apically (10–17 µm long), 2 along inner margin and 1 on posterolateral margin, all probably small and fine; length of anal plates 145–160 µm, width of a single plate 54–60 µm. Ano-genital fold ( Fig. 2h ) with 2 pairs of minute setae present along anterior margin (9–10 µm long) and 2 or 3 pairs of longer fine setae laterally, each 22–25 µm long. Anal ring ( Fig. 2i ) with 8 setae.

Venter. Derm entirely membranous. Multilocular pores absent. Setae: with pairs of long setae on abdominal segments IV–VI measuring 105–110 µm, 70–80 µm and 50–60 µm (those nearest genital opening the longest); shorter setae ( Fig. 2j ), each 15–20 µm long, rather frequent, particularly medially on last few pregenital segments; with 2 pairs of interantennal setae, measuring 30–35 µm and 65–70 µm long, respectively. Submarginal setae ( Fig. 2k ) numbering 32–34 between anterior spiracular clefts, each side with 11–13 between anterior and posterior spiracular clefts and 29–34 between posterior spiracular cleft and anal cleft. Spiracles ( Fig. 2l ) normal with peritreme widths: anterior 28–36 µm, posterior 35–39 µm. Spiracular disc pores ( Fig. 2m ) each mainly with 5 loculi, present in a narrow band between margin and each spiracle, also a very few present more medially near coxae; with 25–55 disc pores in each anterior band and 30–60 in each posterior band. Legs quite well developed, each with tibia and tarsus separate but no articulatory sclerosis ( Fig. 2n ); claws each without a denticle; claw digitules both very broad, 40–50 µm long, longer than claw; tarsal digitules normal, longer than claw digitules (70–80 µm). Dimensions of hind legs: trochanter+femur 232–273 µm, tibia 131–170 µm, tarsus 101–142 µm. Antennae each 6-segmented ( Fig. 2o ), but one specimen with 8 segments on one side and 7 on other; third segment the longest, with 0–2 pseudoarticulations; total antenna length 500–585 µm; segments I–III each with a single fine seta, segment IV with 1 fleshy seta, segment V with 1 fine seta and 1 fleshy seta, and segment VI with 7 fleshy setae and 1 fine seta. Microducts minute ( Fig. 2p ), usually present around mouthparts but very hard to detect on available specimens, probably sparse. Tubular ducts ( Fig. 2q ) each with a wide outer ductule and a rather thin, indistinct, inner ductule with a small terminal gland, only present medially and mediolaterally on abdominal segment VI, in a band of 15–25 ducts. Labium about 75 µm wide.

Comparison: The early descriptions of this species by Green (1904; 1922) are scanty; the redescription by Tang (1991) is in Chinese and therefore not accessible to all. The above description based on Indian material matches those by Green (1904; 1922) and the keys to the species of the genus available, so we are sure that the Indian material is M. piperis .

Ecological notes: Macoccus piperis has been collected only once, at Bengaluru, Karnataka. Perhaps this species does not cause any economic damage at present and hence has been neglected previously, though it is probably present in other pepper-growing areas of India. In the present study, the scale was found in large numbers but more than 90% of the collected specimens had been parasitized, showing the exit holes of emerged adult parasitoids, so we could not collect or rear any parasitoids. This indicates that the population is being kept at a low level by these parasitoids. In the present study no ant species were found attending the scale insects, nor any predators preying on them.

Figures

FIGURE 1. Live appearance of: a. Maacoccus piperis (Green); b. Kilifia deltoides De Lotto; c. Paralecanium machili Takahashi; d. Fistulococcus pokfulamensis Hodgson & Martin; e. Antonina thaiensis Takahashi; f. Formicococcus simplicior (Green).

FIGURE 2. Maacoccus piperis (Green), diagnostic characters of slide-mounted adult female. a. Body derm; b. Marginal setae; c. Stigmatic setae; d. Anal plate; e. Preopercular pores; f. Dorsal seta; g. Preopercular pores; h. Anogenital fold; i. Anal ring; j. Ventral setae on pregenital segments; k. Submarginal setae; l. Spiracle; m. Spiracular pores; n. Hind leg; o. Antenna; p. Ventral microduct; q. Ventral tubular ducts.