Pseudococcus variabilis von Ellenrieder & Watson

Ellenrieder, Natalia Von & Watson, Gillian, 2016, A new mealybug in the genus Pseudococcus Westwood (Hemiptera: Coccomorpha: Pseudococcidae) from North America, with a key to species of Pseudococcus from the New World, Zootaxa 4105 (1), pp. 65-87 : 67-73

Pseudococcus variabilis von Ellenrieder & Watson , sp. nov.

( Figures 1–3 )

Etymology. We name this species variabilis (Latin meaning ‘variable’) in reference to the great variability it displays in the diagnostic characters traditionally used to distinguish between the various groups and species of Pseudococcus , such as the presence or absence of discoidal pores by the eyes and translucent pores on the hind femur.

Type material. Holotype female. U.S.A., California: San Diego County, San Marcos, outdoor landscape on Agave sp., 15.iv.2013, T. Rangel & T. Ellis leg. [ CSCA, PDR # 370P06143551]. Paratypes: 112 ♀, 15 ♂. Ex MEXICO: 1 ♀, intercepted at U.S.A.: Arizona, Nogales on Agave sp., 22.ii.1975, J. Bache-Wiig & G. Ehni leg. [ USNM]; Jalisco State: 2 ♀, El Arenal Municipality, Llano Grande, on A. tequilana , 29.xi.2014, H. González Hernández leg. [ CSCA, molecular vouchers 15T336, 15T337]. U.S.A., California: Los Angeles County: 12 ♀, Redondo Beach, on Agave sp., 29.viii.1992, J. Beardsley leg. [ BPBM]; 12 ♀, Sierra Madre, on A. americana , 24.ix.1993, J. Beardsley leg. [ BPBM]; 4 ♀, Irwindale, in nursery on Agave sp., 31.i.2012, Bakri leg. [ CSCA]; 2 ♀, Malibu, in nursery on Agave sp., 2.iii.2012, I. Milled and Matsumoto leg. [ CSCA]. San Diego County: 5 ♀, Encinitas, outdoors in ornamental planting on A. shawii , 2.xii.2011, D. Kellum leg. [ CSCA]; 2 ♀, San Marcos, in retail outlet on Agave sp., 25.i.2012, A. Romo & T. Ellis leg. [ CSCA]; 2 ♀, same data but [ CPFT]; 10 ♀, 4 ♂, San Marcos, outdoor landscape on Agave sp., T. Rangel & T. Ellis leg., 15.iv.2013 [ CSCA]; 3 ♀, San Diego, in nursery on Agave sp., 11.v.2012, I. Torres leg. [ CSCA]; 3 ♀, Fallbrook, on roadside on Agave sp., 28.vi.2012, I. Torres leg. [ CSCA]; 5 ♀, 4 ♂, Vista, in backyard on Agave sp., 11.vii.2012, I. Torres leg. [ CSCA]; 2 ♀, Vista, in nursery on Agave sp., 22.viii.2012, G. Terhall leg. [ ASCA]; 4 ♀, 1 ♂, Valley Center, in nursery on Agave sp., 23 vii 2012, R. Delaval & M. Wube leg. [ CSCA]; 2 ♀, 1 ♂, San Diego, San Diego Zoo, on Agave sp., 29.ix.2015, T. Ellis leg. [ BMNH]; 2 ♀, 1 ♂, same data but 30.ix.2015 [ FSCA]. Santa Barbara County: 1 ♀, Montecito, in nursery on Agave sp., 29.iii.1981, R.A. Flock leg. [ CSCA]; 5 ♀, Montecito, in nursery on A. americana, J. Karl & G. Davidson leg., 18.x.1984 [ CSCA]; 5 ♀, 4 ♂ (reared), Montecito, in nursery on Agave sp., 28.xi.1984, J. Karl & G. Davidson leg. [ CSCA]; 2 ♀, Santa Barbara, in nursery on Agave sp., 6.iv.1981, Doutt leg. [ CSCA]; 17 ♀, Santa Barbara, in nursery on Agave sp., 1.x.1984, J. Karl leg. [ CSCA]; 5 ♀, same data but [ CPFT]; 5 ♀, same data but [ USNM]; 3 ♀, Carpinteria, in nursery on Aloe [probably incorrect host listed], 22.iii.2012, M.A. Rajala leg. [ CSCA]; 1 ♀, Carpinteria, in nursery on Agave sp., 17.vi.2014, M. Towne leg. [ UCDC].

Description of the adult female. Macroscopic appearance ( Fig. 1 ). Body of live adult female pale pink, with a thin coating of powdery white wax and paired, lateral filaments of white wax on margins of abdomen, with longest pair projecting from posterior-most segment. Color of body in alcohol pale pink-orange, not turning black when placed in 10% KOH (unlike Paracoccus gillianae von Ellenrieder & Stocks , which often occurs on the same host-plants in California).

Slide-mounted characters ( Fig. 2 ). Body of adult female oval, 2.50 ± 0.55 [2.32] (1.48–3.38) mm long, maximum width at level of hind coxae 1.38 ± 0.39 [1.2] (0.72–1.94) mm. Anal lobes moderately developed, each with an apical seta 161 ± 16 [162] (132–180) µm long and ventral sclerotization approximately rectangular. Antennae each 485 ± 26 [474] (456–534) µm long, with 8 segments, distal segment partly divided by an oblique membranous area, mostly visible ventrally but extending partially onto dorsal surface as well, in all examined specimens. Legs well developed, hind tibia 265 ± 21 [276] (240–309) µm long, hind femur 260 ± 21 [270] (219–294) µm long, hind trochanter + femur 332 ± 29 [324] (285–372) µm long, hind tibia + tarsus 360 ± 25 [360] (321–402) µm long; claw well developed, 29 ± 2 [30] (24–33) µm long. Ratio of lengths of hind tibia + tarsus to hind trochanter + femur 1:0.9 ± 0.02 [1:0.9] (1:0.87–1:0.97). Ratio of lengths of hind tibia to tarsus 1:0.4 ± 0.02 [1:0.33] (1:0.31–1:0.38). Dorsal surface of hind tibia distally with 12–67 [5–9] translucent pores, and dorsal surface of hind femur with 0–21 [3–9] translucent pores. Labium 197 ± 13 [204] (180–216) µm long (measured as l in Fig. 2 ); tentorium 216 ± 12 [135] (192–234) µm long (measured as t in Fig. 2 ); ratio of lengths of labium to tentorium 1:0.9 ± 0.05 [1:0.94] (1:0.85–1:0.97). Circulus present between SIII and SIV, 159 ± 26 [132] (102–210) µm wide, divided by intersegmental line. Four apodemes associated with vulva, two anterior and two posterior, always present. Anterior and posterior ostioles moderately developed. Anal ring 96 ± 8 [93] (78–105) µm in diameter, bearing 6 setae, each 129 ± 17 [126] (102–138) µm long. Cerarii numbering 15–16 pairs [16]; anterior metathoracic cerarii (C10) absent, and pair located between anterior ostioles and procoxae (C14) sometimes absent. Anal lobe cerarii (C1) each containing 2 conical setae, each seta 25 ± 2 [24] (24–30) µm long, 5–7 auxiliary setae and a concentration of trilocular pores on a weakly sclerotized area. Other cerarii with conical setae in each cerarius numbering 2 on SII–IX, 2–3 on SI, and 2–4 on thorax and head.

Dorsal surface. Slender flagellate setae of two types present: shorter setae each 9 ± 0.9 [9] (9–12) µm long; longer setae each 39 ± 4 [21] (30–48) µm long. Multilocular pores absent. Trilocular pores evenly distributed except absent from segmental folds. Discoidal pores, each slightly smaller than a trilocular pore, scarce, a few scattered throughout and some located near some OR. OR absent from SVIII, 24–46 [36] present medially, submedially, submarginally, and/or marginally on abdomen in loose rows as follows: SI 1–7 [7]; SII 5–10 [6]; SIII 5–7 [6]; SIV 5–8 [6]; SV 4–7 [5]; SVI 2–5 [3]; SVII 2 or 3 [3]; prothorax 1 or 2 [1]; mesothorax 2–8 [2]; metathorax 6–11 [11]; and head 6–8 [7], with one always present between eye and anterior ostiole on each side.

Ventral surface. Setae, normal, flagellate. Cisanal setae each 49 ± 6 [31] (39–60) µm long, obanal setae each 48 ± 12 [50] (30–72) µm long, anal lobe seta 161.4 ± 16 (132–180) µm long. Multilocular pores each 8 ± 0.4 µm [8] (8–9) in diameter, present in medial area of abdomen, anteriorly as far forward as SI–III, absent from submarginal or marginal areas; thorax with some multilocular pores scattered on medial area near bases of legs. Trilocular pores evenly distributed except absent from segmental lines and around coxal bases. Discoidal pores same size as on dorsum, scattered, with 0–3 [0] situated near eyes. OR present in marginal and submarginal areas of SI or II to SIV and thorax, and near each frontal cerarius on head, absent medially. OC of 2 sizes; larger type slightly wider than and smaller type slightly narrower than a trilocular pore, both fairly numerous, intermixed, forming rows medially on SIII–VIII and marginal groups on SII–VIII; some OC also scattered submedially on head and thorax, with 0–13 [6 or 7] present submarginally on each side at level of front coxa, absent submarginally at level of middle coxa.

Variation. About 50% of females have at least one discoidal pore near one eye, only 1.5% have at least one pore associated with both eyes, and 50% lack discoidal pores near eyes entirely. About 50% of females have 1 to 21 (usually less than 9) translucent pores on hind femur, and 50% lack any on both hind femora. One female (less than 1%) lacks any ventral OC submarginally on both sides at the level of the front coxae (most commonly 5 or 6 present on each side).

Description of the adult male. Slide-mounted characters ( Fig. 3 ). Body of adult male elongate oval, 1.17 ± 0.1 (0.97–1.28) mm long, with maximum width of 0.38 ± 0.04 (0.30–0.46) mm at SIII–IV; both hair-like (hs) and fleshy (fs) setae present throughout. Antennae slightly shorter than half of total body length. Most available males (92 %) brachypterous, with wing buds as long as about 0.08–0.25 of total body length and 0.42–0.64 as wide as long; one male macropterous, with wings 0.86 as long as total body length and 0.49 as wide as long.

Head. Width across genae 181.6 ± 11.5 (164.2–195.2) µm. Each side with about 8–19 dorsal head setae (1–4 fs, 7–15 hs), 11–16 genal setae (6–13 fs, 3–7 hs), 0 dorsal ocular setae, and 0–2 multilocular pores near each scape. Ventral head setae: 15–24 (3–10 fs, 11–14 hs) on each side, in three groups; one situated on longitudinal median line between ventral eyes, another group forming a transverse band between each ocellus and ventral midcranial ridge, and a third along a line on each side of ventral arm of midcranial ridge. With 2 pairs of round simple eyes; dorsal eyes each placed approximately dorso-laterally to ventral simple eyes, each 26.8 ± 1.5 (23.8–28.6) µm wide, ventral eyes 27.2 ± 3.2 (21.4–30.9) µm wide. Ocular sclerites weakly sclerotized, and weakly reticulated dorsally. Ocelli pronounced, situated laterally, each 19.4 ± 2.6 (15.5–23.8) µm wide, located between preocular and postocular ridges. Dorsal arm of midcranial ridge extending beyond posterior margin of dorsal eye, and ventral ridge extending from lateral arms posteriorly to just anterior to ventral simple eyes. Preocular ridge well developed, extending from inner margin of dorsal simple eyes antero-laterally to base of each scape and then postero-laterally to join post-ocular ridge just ventral to each ocellus. Post-ocular ridge well developed, extending from posterior to each dorsal simple eye antero-laterally past each ocellus and then fusing with the preocular ridge before extending postero-laterally to near mouth. Interocular ridge hinted at as a slightly more sclerotized bar dorsad to each ocellus. Preoral ridge weakly developed. Cranial apophysis not detected.

Antennae. Ten segmented and filiform; 522 ± 73.5 (404.6–629.5) µm, as long as 0.45 ± 0.03 (0.40–0.49) of total body length. Scape, 40.3 ± 5.2 (30.9–47.6) µm long, with 6–10 hs. Pedicel 64.4 ± 6.7 (51.2–71.4) µm long, with 6–11 fs, 7–12 hs. Lengths of segments III–X (µm): III, 75.2 ± 12.7 (52.4–95.2); IV, 54.7 ± 10.4 (42.8–73.8); V, 45.8 ± 8 (35.7–59.5); VI, 49.8 ± 9.8 (38.1–64.3); VII, 46.2 ± 8.2 (34.5–57.1); VIII, 44.7 ± 7.2 (32.1–54.7); IX, 44.5± 7.9 (30.9–54.7); X, 56.3 ± 6 (50–71.4). Approximate number of fleshy setae, hair-like setae, and bristleshaped setae (ab) on each segment III–X: III 8–12 fs, 8–17 hs; IV 6–13 fs, 7–11 hs; V 5–10 fs, 4–9 hs; VI 6–10 fs, 5–10 hs; VII 8–11 fs, 6–10 hs; VIII 1 ventral ab, 6–9 fs, 5–8 hs; IX 1 ventral ab, 8–9 fs, 6–7 hs; X 3 subapical ab, 1–5 fs, 4–5 hs, 2 subapical capitate setae; sensilla basiconica not detected.

Prothorax. Pronotal ridge heavily sclerotized; pronotal sclerite represented by a subtriangular sclerotization dorsolaterally. Pronotum medially with 0 or 1 fs, 2 or 3 hs, 0–4 multilocular pores, and 1–3 discoidal pores on each side; post-tergite well developed with 3–6 fs and 1–3 hs. Pronotum laterally with 1–3 hs, 2–11 multilocular pores, and 2–4 discoidal pores. With 1–3 antero-spiracular dorsal hs, 0–2 antero-spiracular dorsal multilocular pores, and 2 or 3 discoidal pores; and with 1 or 2 antero-spiracular ventral hs, 1 or 2 antero-spiracular ventral multilocular pores, and 1–3 discoidal pores. Sternum triangular, with well-developed prosternal ridge; with 0 or 1 fs and 2–5 hs, 0–2 multilocular pores, and 0–2 discoidal pores on each side. Anteprosternal setae absent.

Mesothorax. Prescutum oval, sclerotized, prescutal ridge well developed, prescutal suture distinct, with 0–3 prescutal hs on each side. Scutum sclerotized antero-laterally, with a longitudinal median narrow membranous area, with about 4–8 scutal hs on each side; prealar ridge and triangular plate well developed. Scutellum with 2–4 scutellar hs on each side; anterior and posterior pronotal wing processes well separated. Basisternum bounded anteriorly by a marginal ridge, posteriorly by strong precoxal ridges, median ridge absent, with 4–12 basisternal hs on each side, mainly along anterior and medial area; 6–12 prescutal fs, 3 or 4 prescutal hs on each side; lateropleurite narrow, mesepisternum and mesepimeron distinct; furca well developed, arms divergent and extending about halfway to marginal ridge anteriorly. Mesepisternum sclerotized, subepisternal ridge long and well developed. Postalare without setae. On each side posterior to mesospiracle 4–7 postmesospiracular fs, 1–3 postmesospiracular hs, 1–3 multilocular pores, and 1 or 2 discoidal pores. Tegula present, with 3 or 4 tegular hs.

Metathorax. Metapostnotal sclerite and metapleural ridge well developed; with 5–8 metatergal hs on each side; precoxal ridge well developed and metasternal apophyses distinct. Metepisternum and metepimeron weakly sclerotized. 1 metapleural fs, 0–2 hs, and 2 or 3 multilocular pores posterior to each metathoracic spiracle. Metasternum membranous, on each side 1 or 2 anterior metasternal fs and 2 or 3 hs, 2 or 3 anterior multilocular pores, and 1 or 2 anterior discoidal pores.

Wings. Hyaline, in macropterous male 1,101.6 mµ long and 541 mµ wide, in brachypterous males 88.1–309.4 mµ long and 50–130.9 mµ wide. Ratio of length to width 1:0.5 ± 0.1 (1:0.42–1:0.64); ratio of total body length to wing length 1:0.2 (1:0.08–1:0.86); alar lobe well developed and each wing with 2 or 3 alar setae in both macropterous and brachypterous males; 1 or –2 circular sensoria in macropterous male, absent in brachypterous males. Hamulohalteres fully developed, 64.3 µm long with an apical hamulus in macropterous male; in brachypterous males entirely absent in those with wing buds less than 155 µm long, and represented by a membranous lobe 36.9–39.3 µm long with no apical hamulus in those with wing buds longer than174 µm.

Legs. Metathoracic legs longest; hind femur 197.4 ± 24.7 (161.8–229.7) µm; hind tibia 243.6 ± 35.6 (185.6–297.5) µm; hind tarsus 98.5 ± 26.5 (76.2–102.3) µm; hind tarsal claw 28.8 ± 1.8 (26.2–30.9) µm. Ratio of hind femur length to hind tibia length 1:1.2 ± 0.1 (1:1.15–1:1.32); ratio of hind tibia length to hind tarsus length 1:0.4 ± 0. 1 (1:0.35–1:0.57). Hair-like and fleshy setae present, numbering: coxa I 0–3 fs, 6–14 hs, II 2–6 fs, 7–12 hs, III 4–8 fs, 10–20 hs; trochanter I 0–2 fs, 1–3 hs, II 0 fs, 3 or 4 hs, III 0–2 fs, 3 or 4 hs; femur I 1–7 fs, 26–40 hs, II 2–16 fs, 29–38 hs, III 8–22 fs, 23–28 hs; tibia I 15–22 fs, 28–34 hs, II 12–38 fs, 25–44 hs, III 16–37 fs, 30–32 hs; tarsus I 0 or 1 fs, 17–25 hs, II 0–2 fs, 18–28 hs, III 0–3 fs, 16–27 hs. Each trochanter with 3 campaniform pores arranged in a triangle medially on each side. Tibiae with apical spurs: I 2–4, II 3–6, III 3–7. Tarsi 2 segmented, tarsal digitules capitate, claw digitules acute.

Abdomen. SI–VII: Small slightly sclerotized abdominal tergites present sometimes medially on SVII (detected in 3 specimens). Sternites unsclerotized except for a small anterolateral area on each side of SVIII, and usually around base of setae of SVIII and sometimes also of SVII. Each segment with dorsal setae numbering: SI 0–2 fs, 5 or 6 hs; SII 0–4 fs, 5–7 hs; SIII 0–4 fs, 6–8 hs; IV 1–5 fs, 5–8 hs; SV 3–6 fs, 6–8 hs; SVI 2–6 fs, 5–7 hs; SVII 0–3 fs, 4–8 hs; pleural setae and pores on each side numbering: SI 4–5 hs + 3–10 multilocular pores + 4–5 discoidal pores; SII 3–5 hs + 1–5 multilocular pores + 3–5 discoidal pores; SIII 3–5 hs + 0–4 multilocular pores + 2–4 discoidal pores; SIV 4–5 hs + 0–3 multilocular pores + 1 or 2 discoidal pores; SV 4 or 5 hs + 1–5 multilocular pores + 2 or 3 discoidal pores; SVI 4 or 5 hs + 1–6 multilocular pores + 3–5 discoidal pores; SVII 5 or 6 hs + 1–8 multilocular pores + 3–5 discoidal pores. Ventral setae numbering: SII 0–4 fs, 2–13 hs; SIII 0–4 fs, 6–8 hs; SIV 1–5 fs, 5–8 hs; SV 3–6 fs, 6 or 7 hs; SVI 2–6 fs, 4–6 hs; SVII 0–3 fs, 4 or 5 hs. With a pair of indistinct ostioles laterally between segments SVI and VII. SVIII: tergite slightly sclerotized medioposteriorly with 4 or 5 hs, and with 6–8 anteanal setae; sternite with a small slightly sclerotized anterolateral area on each side of SVIII, without ventral setae; caudal extension rounded with 2 or 3 pleural setae, their bases usually surrounded by a small sclerotized area. Glandular pouches shallow, each with 7–28 multilocular pores spreading out around pouch, 1–3 discoidal pores, and 2 long glandular pouch setae, each 312.5 ± 11.6 (295.1–335.6) µm long, and 1 shorter seta, 55.9 ± 10.7 (47.6–71.4) µm long.

Genital segments. Penial sheath subtriangular, 146.7 ± 10.2 (130.9–161.8) µm long, 83.4 ± 6.3 (72.6–90.4) µm wide across basal ridge, ratio of penial sheath length to width 1:0.6 ± 0.03 (1:0.54–1:0.63). Anal opening not detected but probably present just posterior to tergite SIX on dorsal surface. Dorsally with 3 small setae near base of style on each side. Ventrally, style approximately parallel sided with truncate apex; basal ridge well developed and with a small anteromedial projection on each side; lateral processes of penial sheath indistinct; with 2–6 small setae on anterior portion of penial sheath and a row of 2–6 minute setal sensilla along medial side of penial sheath slit. Basal rod distinct, extending anteriorly to basal ridge. Aedeagus 104.2 ± 10.8 (88.1–121.4) µm long, approximately parallel sided, tapering apically to a blunt point, extending beyond end of penial sheath to 0.66–0.75 of style length.

Diagnosis. Females of Pseudococcus variabilis differ from females of all other species of Pseudococcus known to feed on Agavaceae except for Pseudococcus floriger Ferris in Zimmerman and P. orchidicola Takahashi ( Table 1 ), and from most other species of Pseudococcus known from the New World ( Table 2 ), by the presence of a ventral OR posterior to each frontal cerarius. The following combination of characters allows separation of females of P. variabilis from these two species as well ( Tables 1 , 2 ): presence on each side of a dorsal OR between eye and anterior ostiole; ventral OC on thoracic submargin present at level of front coxa only; translucent pores on hind leg limited to tibia and femur; 15 or 16 pairs of cerarii, those on SII (C7) well developed; ventral multilocular pores on abdomen present from SVIII to SIV or III; eye lacking a sclerotized rim; dorsal setae 30–48 µm long; hind tibia 240–309 µm long; anal lobe seta 132–180 µm long.

Adult males of 11 species of Pseudococcus have been described: P. antricolens , P. calceolariae , P. comstocki , P. cryptus , P. floriger , P. longispinus , P. lycopodii , P. montanus , P. multiductus Beardsley , P. pipturicolus , and P. viburni ( Beardsley 1960, 1962; Gilliomee 1961; Afifi 1968). With the exception of P. multiductus (which is Australasian), all the other species occur in the New World. The adult male of P. variabilis shares the penial sheath medial slit lacking distinct lateral processes only with those of P. ca l ce o l a r i a e, P. comstocki , P. c r yp t us, and P. viburni . It differs from these four species (character-states for other species in parenthesis) in having: (a) tip of aedeagus simple (forked in P. viburni ), (b) dorsal and ventral abdominal setae subequal to or shorter than half the length of the segment they occupy (longer than half the length of the segment they occupy in P. calceolariae ), (c) penial sheath 131–162 µm long, with sides narrowed abruptly at level of base of style (penial sheath 200 µm long, tapering gradually to tip of style in P. cryptus ), and (d) basal ridge of penial sheath with a small anteromedial projection on each side, penial sheath ventrally with 2–6 small setae on anterior portion and a row of 2–6 minute setal sensilla along each side of medial slit (basal ridge of penial sheath lacking projections, penial sheath ventrally with about 12 small setae on medial portion and no row of minute setal sensilla along each side of medial slit in P. comstocki ).

Molecular data. The DNA sequences of Pseudococcus variabilis are available at GenBank under the following accession numbers and associated data:

KU234772 , Pseudococcus variabilis von Ellenrieder & Watson, U.S.A. , California, San Diego County, Encinitas, on Agave shawii , 2 xii 2012, D. Kellum leg., CSCA- FTC code 11H102; KU234773 , P. variabilis von Ellenrieder & Watson, U.S.A. , California, San Diego County, Oceanside, on Agave vilmoriniana , 2 xi 2011, G. Terhall leg., CSCA- FTC code 11H103; KU234774 , same data but CSCA-FTC code 11H106; KU234772 , same data but on variegated Agave , CSCA- FTC code 11H110; KU234776 , P. variabilis von Ellenrieder & Watson , Mexico, Jalisco, El Arenal, Llano Grande, 29 xi 2014, H. González Hernández leg., CSCA-FTC code 15T336; KU234777 , same data but CSCA- FTC code 15T337.

The COI sequences of the specimens of P. variabilis from Encinitas and Oceanside in California differ by one base pair (out of about 600 base pairs), and they differ from the sequences of the specimens from Mexico by eight (about 1.3 %) and nine (about 1.5 %) base pairs.

Pseudococcus variabilis differs from the other Pseudococcus species sequenced so-far for a comparable sequence of the COI (based on Park et al. 2011 sequences in GenBank and CSCA database) by 10–11 % ( P. pseudobscurus ), 11.8–12.3 % ( P. maritimus , P. viburni ), 13 % ( P. comstocki ), 12.9–13.2 % ( P. longispinus ), and 14–15 % ( P. calceolariae , P. cryptus , P. importatus , P. jackbeardsleyi ).

Hosts. Agave spp., including A. americana , A. shawii , A. tequilana blue variety, and A. vilmoriniana ( Liliales : Agavaceae ). The single record on Aloe (Xanthorrhoeaceae) is probably an error in host labeling.

Biology. Adult females of P. variabilis produce cottony ovisac wax that, in heavy infestations, coalesces into a mass of wax mixed with females, eggs, crawlers and males ( Fig. 1 a). The mealybugs are generally restricted to the underside of the leaves and infestations are usually heavier on the lower leaves ( Fig. 1 b), which appear shriveled, brown, and covered in wax, and can eventually die. In Mexico, P. variabilis was reported infesting Agave tequilana (blue variety) plants, used in the production of tequila, from the base near the roots to the underside of the leaves and the leaves at the heart ( González Hernández et al. 2007 as Pseudococcus sp. nov.). González Hernández et al. (2007) studied the fluctuations in population density of P. variabilis in three areas of Jalisco where A. tequilana is grown and found that it peaks in July, or July and August, and decreases in winter, from December to March or April. They also mentioned that several unidentified species of Encyrtidae (Hymenoptera) parasitize P. variabilis in these populations. López Domínguez (2008) recorded an average incidence of 7.12 % by the encyrtid parasitoid Pseudleptomastix mexicana Noyes and Shauff on P. variabilis in Jalisco. Populations of P. variabilis from California are occasionally found coexisting with P. gillianae .

Distribution. Pseudococcus variabilis was not recorded by McKenzie (1967) for California, so it is probably native to Mexico and is only more recently adventive to southern California. The species appears to be moving about in the nursery trade on Agavaceae , and it could also have been introduced to other southern states of the United Sates where its host plants are used for landscaping. In California, it has been found in nurseries in Los Angeles, San Diego, Santa Barbara and Riverside Counties, and outdoors in landscaped areas in the first three counties. In Mexico, it has been recorded from Jalisco State as Pseudococcus sp. nov. ( Solis Aguilar et al. 1999; González Hernández et al. 2007) infesting Agave tequilana but it most likely has a wider distribution and host range within Agavaceae .

Figures

FIGURE 1. Pseudococcus variabilis sp. n. Macroscopic appearance. 1 a. Adult female, ovisac wax, eggs and juveniles on Agave sp. leaf from Nursery in Irwindale, California, U. S. A. Photograph: Gevork Arakelian. 1 b. Agave sp. plant at the San Diego Zoo in California, U. S. A., with infestation of Pseudococcus variabilis sp. n. near base and on underside of lower leaves. Photograph: Tracy Ellis.

FIGURE 2. Pseudococcus variabilis sp. n. Holotype female, U. S. A., California, San Diego Co., on Agave sp., deposited at CSCA. Enlargements of structures are not drawn to scale. l: measurement of labium length; t: measurement of tentorium length.

FIGURE 3. Pseudococcus variabilis sp. n. Male paratype, U. S. A., California, San Diego Co., on Agave sp., deposited at CSCA. Enlargements of structures are not drawn to scale.