Lachnodius lectularius Maskell, 1896

Hardy, Nate B., Beardsley Jr, John W. & Gullan, Penny J., 2019, A revision of Lachnodius Maskell (Hemiptera, Coccomorpha, Eriococcidae), ZooKeys 818, pp. 43-88 : 43

Lachnodius lectularius Maskell, 1896 Figs 2a, b, 7

Lachnodius lectularius Maskell, 1896: 400-402.

Diagnosis.

Gall of adult female does not cover any of dorsum; adult female with marginal fringe of close-set setae; one size class of dorsal macrotubular ducts.

Description.

Adult female (n> 10). Body outline circular to oval; length 2.1-9.3 mm (4.0 mm for lectotype), greatest width 1.9-7.4 mm (3.0 mm for lectotype). Eyes 25-50 μm wide, on margin. Antennae seven-segmented; length 620−1440 μm; with 3-6 hair-like setae on segment I, 5-13 hair-like seta on segment II, 3-5 hair-like seta on segment III, 2-6 hair-like seta on segment IV, 2-3 hair-like + one fleshy seta on segment V, 2-4 hair-like setae + one fleshy seta on segment VI and six hair-like setae + three fleshy setae on segment VII. Frontal lobes 155-440 µm long, 88-175 µm wide. Tentorial box 330−500 μm long, 180-270 μm wide, with anterior extension of the dorsal arms. Labium 140-250 μm long, 120-190 μm wide. Spiracles 140-290 μm long, 100-285 μm wide across atrium. Legs: trochanter + femur 500-1340 μm, tibia 370-1150, tarsus 150−300 μm; claw 53-120 μm; coxa with 5-10 setae, trochanter with 6-14 setae, femur with 13-35 setae, tibia with 19-41 setae, tarsus with 11-21 setae; tarsal digitules 70-125 μm long, claw digitules 50-70 μm long; translucent pores on all segments of hind leg. Anal ring 73-185 μm wide, with 15-24 setae; ring setae 43-210 μm long. Pair of elongate caudal setae absent.

Dorsum. Derm membranous. Dorsal setae 5-8 μm long, each with constriction near base and apex acute, scattered over dorsum. Macrotubular ducts with rim of dermal orifice 5 µm in diameter, duct shaft 10-14 µm long, scattered over dorsum. Microtubular ducts ca. 5 μm long, with rim of dermal orifice ca. 2 μm wide, scattered over dorsum. Dorsum delimited by fringe of setae, each 38-90 µm long, ca. 300 setae in total on each side of body.

Venter. Ventral setae 15-210 μm long; elongate setae medial of each coxa 60-190 μm long; longest setae on head 165-300 μm long. Macrotubular ducts similar to those on dorsum; found wherever setae occur, in transverse band across each segment, scattered throughout submargin. Quinquelocular pores 5 μm in diameter, distributed as macrotubular ducts, with cluster near each spiracle, dense on median of posterior abdominal segments, near vulva.

Notes.

Adult females feed in a pit in a swollen stem or bud of the host eucalypt (Fig. 2a, b). The body color is variable; it is green with a red longitudinal stripe on the dorsum of younger females and fully orange or red to brown in older females. In life, females can lift up their abdomen and expose their venter. Each seta forming the marginal fringe surrounding the dorsum is covered in a glassy secretion. The life history of L. lectularius is similar to that of L. eucalypti . For details see Notes under L. eucalypti . One exception is that the galls of developing young females of L. lectularius are located on succulent young twigs and buds rather than on leaves. Mature females of L. lectularius were collected by JWB from Eucalyptus camaldulensis at La Trobe, and on other hosts and localities in Victoria during a relatively short period (February 14 to 20, 1972). This suggests that L. lectularius may reproduce with more synchrony than L. eucalypti . Eggs from females of L. lectularius held in the laboratory by JWB began to hatch approximately two weeks after oviposition.

In an unpublished manuscript, JWB treated as a separate species some of the larger specimens of what we consider to be L. lectularius . He noted that these specimens closely resemble the type material of L. lectularius and that the first-instar nymphs were identical, but pointed out several differences: specifically, the larger females have longer setae, more tubular ducts, a larger anus, more expanded tibial apices, and more translucent pores on the hind legs. Each of these traits appears to be correlated with body size across Lachnodius species. Therefore, we have opted to interpret this as part of the phenotypic variation found within L. lectularius .

Maskell (1896) described the adult female, the second-instar female, and the first-instar nymph of this species. Apparently, his description was based on material sent to him from Victoria by Mr C French. Type material of this species consists of specimens on 6 unstained slides prepared by Maskell, one adult female in the USNM and eleven adult females mounted by JWB from specimens from two boxes of dried material in NZAC. The original Maskell slides are labelled "Dactylopius lectularius" with “Dactylopius” crossed out and “Lachnodius” written above it, and "1895 - W. M. M." There are no locality or collector data on these slides. The dry material was labelled only "Dactylopius lectularius - Australia" but the boxes were lost (see explanation in Materials and Methods). Only one of the original Maskell slides contains an entire adult female. JWB labelled that specimen as the lectotype in 1972 but this action was not published until now (see below). Of the remaining slides (paralectotypes), one contains female mouthparts, one the posterior body and antenna of an adult female, one a second-instar female, and two contain first-instar nymphs. When JWB slide-mounted specimens from Maskell’s dry material in 1972, he labelled the slides with the collection data from the original description (but with the wrong collector name), rather than what was written on the box.

Concerning the type material of L. lectularius , Maskell (1896: 401) only stated that "Mr. French has sent me a number of specimens and says, 'It does great damage to young trees at Mooroopna, Goulburn River, Victoria’.” Therefore, we assume that all of his material was from this one source. Specimens in the dry material are mostly parasitized mummies, and JWB only obtained two satisfactory slide preparations. Both of these adult females show evidence of having been parasitized, containing parasitoid mandibles, encyrtiform eggshells, and small sclerotized first-stage parasitoid larvae. Maskell (1896: 401) recorded the habitat from which the type material was derived as "In Australia, on Eucalyptus rostrata." Eucalyptus rostrata is a junior synonym of E. camaldulensis , the "river red gum," a common species throughout southeastern Australia ( Chippendale 1988).

The adult female specimens of L. lectularius in the Maskell collection do not agree in all details with his published description and figures. We consider that the discrepancies are errors in Maskell’s interpretation. Morrison and Morrison (1922) noted that Maskell’s descriptions often were inaccurate. Here we point out the mismatches between his description and specimens. In his 1896 description, Maskell stated that the adult female has an "Epidermis bearing many short fine hairs, and near the cephalic and abdominal extremities are two curved series of stronger spiny hairs, about sixty in each." His figure of the female abdomen ( Maskell 1896: Plate XXI, fig. 16) shows a series of spine-like setae in the area behind the anal ring. In the drawing these are thicker and more conical in form than the fringe setae, which are depicted (Plate XXI, fig. 17) as being nearly digitiform. By contrast, the Maskell specimens do not have conical or spiniform setae posterior to the anal area, although many of the setae appear to have been broken off and look somewhat like stiff bristles. On the other hand, in fresh preparations, the ventral setae in this region are quite elongate. Thus, we think that he simply confused body surfaces. Maskell also refers to a pair of "strong short conical spines" set close together between the antennae in some specimens, but not in all. In this position in the lectotype, we found a pair of parasitoid mandibles, which he must have mistaken for spines. Likewise, he mistook several pairs of parasitoid mandibles for spines in his description of the second-instar female. Maskell counted 24 of these structures, which is consistent with JWB’s observation that the encyrtids that attack Lachnodius species can be highly gregarious.

In his notes, JWB recorded having studied two specimens that were not seen by PJG or NBH: Queensland: two adult females: Eucalyptus sp., gall no. 9, Acacia Ridge, Brisbane, 10 Jan1968, EC Dahms (these probably are housed in the Queensland Museum in Brisbane).

Material examined.

Lectotype (here designated): Victoria: adult female: on slide labelled: "Lachnodius / Dactylopius / lectularius / adult female / 1895 W.M.M." (ANIC). Paralectotypes: Victoria: five slides: adult female mouth parts, adult female posterior body and antennae, one second-instar female, and two first-instar nymphs: same label data as lectotype (NZAC); eleven adult females, on six slides prepared and labelled by JW Beardsley from Maskell dry material: "VICTORIA / Mooroopna / Goulburn Riv. /?1896 / W. W. Froggatt [SIC] / Eucalyptus / rostrata in / twig depression" (NZAC); one adult female, on slide labelled: "Lachnodius / lectularius / Mask. / Australia / Mask. Coll. No. 453" (USNM). Note that JWB made an error in writing the collector as "W.W. Froggatt", as the original specimens were collected by C. French. Also, the dry material that JWB mounted did not bear the collection data that he put on his slide labels, but was added by JWB based on the data cited in Froggatt’s original description. Additional material: Australian Capital Territory: one adult female, ex pit in swollen woody stems, Eucalyptus sp., Canberra, Black Mountain, Coll. 6 Dec 1996, JH Martin 6845 (ANIC). New South Wales: three adult females: Eucalyptus sp. (bloodwood), 5 km W of Bogangar, 23 Nov 1986, S Bhatti, PJG, and C Reid (ANIC); two adult females: ex pits in swollen stems, E. dives , 2 km S of Captain’s Flat, 35.58S, 149.47E, 4 Jan 2009, PJG (ANIC); one adult female: ex pit gall, Eucalyptus sp., Congo, 35.95S, 150.15E, 6 Jan 1992, PJG (ANIC); one adult female: ex swollen stem, Eucalyptus sp., 22 km NE of Griffith, Whitton Stock Route, 34.15S, 146.20E, 30 Oct 1993, PJG (ANIC); one adult female: Eucalyptus sp., E of Walcha, Oxley Highway, 31.21S, 151.90E, 1130 m, 25 May 2005, LG Cook, LGC00345, NH87 (ANIC); two adult females: ex depressions in swollen fruit, Eucalyptus sp., N. Sydney, Beacon Hill, Peninsula Views Estate, 18 Sep 1993, LG Cook, LachB (ANIC). Queensland: four adult females (all parasitized): Eucalyptus drepanophylla , R-8 Doongul, 27 Sep 1939, AR Brimblecombe (QDPC); one adult female, three second-instar nymphs, 14 first-instar nymphs: E. crebra , Moggill, 20 Nov 1953, AR Brimblecombe (QDPC) (these three slides could not be located at QDPC). South Australia: eleven adult females, three second-instar females, one first-instar nymph: ex swellings on twigs or stems, E. camaldulensis , Glen Osmond, 6 Oct 1982, GS Taylor, HMB Specimen Index No. 20/82 (ANIC). Victoria: five adult females, seven first-instar nymphs: ex pits in twigs, Eucalyptus radiata , 20 miles [32 km] W of Drouin, 20 Feb 1972, JWB (BPBM except one slide of nymphs in ANIC); 14 first-instar nymphs: ex ovisac on bark, E. camaldulensis , Bundoora, La Trobe University, Coll. 21 Feb 1972, JWB (BPBM); three adult female: ex pits in twigs, E. camaldulensis , Bundoora, La Trobe University, Coll. 14 Feb 1972, JWB (BPBM); two adult females, one second-instar male: under bark, E. camaldulensis , Bundoora, La Trobe University, Wildlife Reserves, Ring Road, 37.72S, 145.05E, 14 Feb 2005, NBH and PJG, NH41, NH154, NH161 (ANIC); two adult females: ex pits in swollen stems, E. viminalis , Cranbourne, Royal Botanic Gardens Cranbourne, Possum Gully Track, 38.13S, 145.28E, 9 Feb 2005, PJG, NH40, NH115 (ANIC); one adult female: ex pit in swollen stem, E. aromaphloia , Grampians Nat. Park, Victoria Valley, Glenelg River Road, 37.23S, 142.41E, 6 Feb 2005, NBH and PJG, NH119 (ANIC); one adult female: ex pit in swollen stem, E.?polyanthemos, Melbourne, North Warrandyte, corner of Overbank Road and Glynns Road, 37.73S, 145.20E, 14 Feb 2005, NBH and PJG, NH46 (ANIC); one second-instar female: ex pit in twig, E. radiata , Mt Eliza, 22 Feb 1972, JWB (BPBM); one adult female: in depression on swollen stem, Eucalyptus sp., near Hattah, Nov 1993, LG Cook (ANIC); five adult females, one second-instar female: ex pits in twigs, E. viminalis , Tooborac, 24 Feb 1972, JWB (BPBM); two adult females: ex pits in flower buds, E. viminalis , Tyabb, junction of Tooradin-Tyabb Road and Callanans Lane, 38.21S, 145.25E, 13 Feb 2005, NBH and PJG (NMV).