Valid Names Results

Bystracoccus mataybae Hodgson, Isaias & Oliveira, 2013 (Eriococcidae: Bystracoccus)

Nomenclatural History

• Bystracoccus mataybae Hodgson, Isaias & Oliveira 2013: 317-330. Type data: BRAZIL:Uberlândia, Minas Gerais, in leaf gall on Matayba guianensis, 7/9/2011, by D. Oliveira. Holotype, female and first instar, by original designation Type depository: Belo Horizonte: Taxanomic Collection of UFMG , Brazil; accepted valid name

Common Names

Ecological Associates

Hosts:

Families: 1 | Genera: 1

Geographic Distribution

Keys

Remarks

• Systematics: In having the dorsal surface of the abdomen heavily sclerotised, Bystracoccus shows some affinities with Aculeococcus Lepage, another eriococcid genus found in South America (and China) (Hodgson & Miller, 2010). However, on the latter, the sclerotisation also covers the dorsum of the thorax and most of the head as well. In addition the division into head, thorax and abdomen is reasonably clear on Aculeococcus whereas this is obscure on Bystracoccus. Other apparent similarities between adult females of these two genera are: (i) venter becoming much larger than dorsum on mature adults; (ii) legs complete but mainly malformed and obviously nonfunctional; (iii) metacoxae either becoming much enlarged or with a sclerotised area of venter associated with each metacoxa; (iv) absence of macrotubular ducts, and (v) mouthparts with a large pair of apodemes extending anteriorly from tentorial box. Bystracoccus differs from Aculeococcus, however, in the complete absence of multilocular disc-pores on the abdomen, whereas they form broad bands across several of the more posterior segments in the latter species. (Hodgson, et al., 2013) Other genera of South American Eriococcidae that have onion-dome-shaped setae in the first instar nymph are Aculeococcus Lepage and Tectococcus Hempel (Hodgson & Miller, 2010). The first instar nymph of B. mataybae differs from the latter in having two types of dorsal setae (only one type, in a submedial row, in T. ovatus) and from that of A. morrisoni Lepage in having only 3 pairs of onion-dome-shaped pores medially whereas A. morrisoni has six. The distribution of the non-onion-dome-shaped setae is also quite different, those on A. morrisoni being restricted to medially on abdominal segments III, V & VI. Of the known first-instar nymphs of South American eriococcids, that of B. mataybae appears to be most similar to that of A. morrisoni. (Hodgson, et al., 2013) The sclerotised dorsal plate of the adult female of this species bears a close resemblance to that of Danumococcus parashoreae, currently included in the Beesoniidae. Despite this great similarity in the adult females, Bystracoccus is considered to belong to the Eriococcidae because of the similarity of the first-instar nymphs to those of other eriococcids, and thus the similarity between the dorsal plates of Danumococcus and Bystracoccus appears to be a good example of convergent evolution. (Hodgson, et al., 2013)
• Structure: Adult female approximately round in dorsal view but margin indented laterally near anterior spiracles and almost flat ventrally. Derm mainly membranous apart from large mediodorsal sclerotised plate, latter 200-350 µm long, 230-380 µm wide. Venter expanding greatly during maturity, probably forming most of derm in oldest specimens. Margin not demarcated and without marginal setae. Eyespots apparently absent. The uppermost surface of the dorsal plate appears to be fairly smooth and more or less round, with a flat surface, but with a narrow marginal indentation posteriorly, which is probably the anal cleft, and this extends ventrally to the anal ring which has setae but no pores. The anal ring, thus, appears to lie beneath the upper surface of the dorsal plate. The upper surface of the dorsal plate has two pairs of small setose setae towards the anterior margin and two lines of small pores along each posterolateral margin. The dorsal plate looks as though it has been formed by fusion of the dorsums and margins of all of the abdominal segments. However, lying "beneath" the upper surface of the dorsal plate is what appears to be another layer! This layer has a series of large, heavily sclerotised apodemes arising from it which also appear to be segmentally arranged (i.e. there are about seven pairs) and extend more or less laterally. In the mature adult female, these apodemes are very well developed and extend a long way out from beneath the margins of the dorsal plate.(Hodgson, et al., 2013) Second-instar female similar to adult female but smaller; body more or less round when young but becoming flask-shaped with a rounded "bottom" and a short "neck" when older. Body red in life. (Hodgson, et al., 2013) First-instar nymph body reddish about 0.25 mm long and oval. Wintering population inducing pit galls on twigs. (Hodgson, et al., 2013)
• Biology: Inducing galls on the leaf of Matayba guianensis (Sapindaceae), with gall opening on upper (adaxial) leaf surface. Each gall with a funnel-shaped outer chamber and a roundish inner chamber. Gall opening slightly recessed on upper leaf surface but forming a round convex mound on lower leaf surface; each mature gall 5-6 mm wide. Body of insect flask-shaped with a flat "bottom" and a short "neck", latter with heavily sclerotised dorsal plate on apex that fills inner cavity opening. Body red (but white when stored in alcohol). (Hodgson, et al., 2013) Gall induction takes place in the youngest leaves, most commonly in September and October. The leaf galls are light green with red spots, are glabrous and intralaminar, with a narrow projection through which the gall opens on the adaxial surface. The galls are all similar in shape and size, each with two chambers, an outer chamber which appears to be empty and an inner chamber in which the insect lives. There is just one insect in each gall. Small galls are also abundant on the twigs of M. guianensis during the dry season (winter) (June-August). These pit galls are about 2 mm across, each with a single first-instar nymph in the center and when very abundant, the galls tend to fuse. (Hodgson, et al., 2013)
• General Remarks: Detailed description, illustrations, and photographs of galls in Hodgson, et al., 2013.

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Citations