Aleurodamaeus setosus ( Berlese, 1883 )

Seniczak, Stanisław, Ayyıldız, Nusret & Seniczak, Anna, 2012, Setal losses in the dorsal hysterosoma of Plateremaeoidea (Acari: Oribatida) in the light of ontogenetic studies, Journal of Natural History 46 (7 - 8), pp. 411-451 : 413-423

Aleurodamaeus setosus ( Berlese, 1883)

( Figures 1–8 , 9A )

Damaeus setosus Berlese, 1883 .

Gymnodamaeus gibbus Mihelčič, 1963 .

Gymnodamaeus nitidus Mihelčič, 1956 .

Aleurodamaeus setosus: Pérez-Íñigo 1972, 1995 ; Sergienko 1980; Subías 2004, 2011; Moraza and Peña 2005; Akrami 2007; Melamud et al. 2007.

Diagnosis

Adult dark brown, medium size (550–660 µm), and of damaeid shape ( Figure 1 ), with well-developed pedotecta behind acetabula I and II. Setae ro and le rather long ( Table 1), curved, seta ex shorter, seta in small. Bothridium rather large, rounded; sensillus long, setiform. Notogaster oval, arched, with four posterior pairs of setae (h 1 and p -series). Body and setae covered with granules of cerotegument ( Figures 2 , 3 ). Lyrifissures ia, im and ip conspicuous ( Figure 4A ). Adult often with gastronotic exuviae (scalps) of previous instars. Seven pairs of evenly distributed genital setae, and two pairs of adanal setae ( Figure 4B ). Formula of leg setae (and solenidia): I – 1-5-4(1)-4(2)-18(2), II – 1-4-4(1)-4(2)-16(2), III – 2-2-2(1)-4(1)-13; IV – 1-2-2-3(1)-13. Legs tridactylous.

Juveniles of damaeid shape, unpigmented. Prodorsal setae ro and le rather long, curved, seta in long in larva, but short in nymphs, seta ex of medium length in all juveniles. Bothridium of larva relatively larger than in nymphs, but sensillus long in all juveniles. Larva with 12 pairs of gastronotal setae, with longer dm, dp and h 1, nymphs also with 12 pairs, with long setae c 1, h 1, h 2 and p 1; large setae on tubercles. Body and setae covered with granules of cerotegument. Nymphs with gastronotic exuviae of previous instars, loosely fastened to gastronotum by long, distally flagellate gastronotic setae, tangled with setae of exuviae.

Description of juvenile stages

Larva of damaeid shape ( Figure 5 ), and unpigmented. Prodorsum subtriangular, with rounded rostrum, broadened behind level of leg I. Prodorsal setae rather long ( Table 1), ro and le strongly curved, other setae slightly curved; in longest, ex shortest. Bothridium large, rounded, with funnel-like rim protruding above surface; sensillus setiform and curved posteriorly.

Gastronotum with 12 pairs of setae, including h 3 inserted lateral to centre of anal opening ( Figure 6A ). Setae c 2 and h 3 short, other setae longer and curved, except for large dm and dp, and slightly smaller h 1; large setae on large tubercles; all long setae flagellate in distal parts. Paraproctal valves (segment PS) with two pairs of small setae. Gland opening gla lateral to seta h 3. Cupule ia posterior to seta c 3, cupule im anterior to seta lm, cupule ip between setae h 1 and h 2, and cupule ih near anterior margin of paraproctal valves. Anterior and lateral part of gastronotum with few folds. Body and most setae covered with granules of cerotegument.

Nymphs of damaeid shape, unpigmented, body and setae with granules of cerotegument. Gastronotum of protonymph with 12 pairs of setae; d -series lost and remain absent in deutonymph and tritonymph, whereas pseudanal setae (p 1 – p 3) appear on segment PS ( Figure 6B ), and remain in deutonymph ( Figure 7A ) and tritonymph ( Figure 7B ). Protonymph forms small posterior excrescence, with two pairs of setae (h 1 and h 2); all setae raised and flagellate in distal parts; in deutonymph similar, in tritonymph wider, with three pairs of setae (h 1, h 2 and p 1). In all nymphs seta lm inserted near seta lp and far from seta la. Genital valves of protonymph with single pair of short setae, three pairs added in deutonymph and two more pairs added in tritonymph. One pair of aggenital setae appears in deutonymph, lateral to genital valves, and remains in tritonymph. All genital papillae rather large, with typical development (one, two and three pairs in protonymph, deutonymph and tritonymph, respectively). Paraproctal valves of protonymph (segment AD) and Notes: Measurements are mean measurements of 4– 10 specimens in µm.

L, larva; PN, protonymph; DN, deutonymph; TN, tritonymph; AD, adult; Nd, not developed.

deutonymph (segment AN) glabrous, those of tritonymph with two pairs of small setae. In deutonymph two pairs of small adanal setae (ad 1, ad 2) appear on segment AD, and remain in tritonymph.

Prodorsum of tritonymph ( Figure 8 ) more triangular, and longer, relative to width, comparing to larva, prodorsal setae as in larva, except for minute seta in. Bothridium rounded, funnel-like, but relatively smaller than in larva, sensillus long, setiform. Nymphs with scalps of previous stages, with reticulate cuticle and some setae. Seta c 1 long, flagellate and tangled distally with setae on exuviae; setae c 2 and c 3 shorter. Setae h 1, h 2 and p 1 long, inserted on posterior excrescence, flagellate distally and tangled with setae on exuviae; all long setae on small tubercles. Exuviae loosely but securely connected to gastronotum mainly by rather short setae c 3, and long setae c 1, h 1 and h 2, and rarely lost from specimens during preparation on slides. Gland opening gla between setae lm and p 3. Cupules ia and im as in larva, cupule ip anterior to seta p 1, cupule iad lateral to anterior margin of anal opening, cupules ips and ih pushed laterally from anal opening. Tarsus I of tritonymph elongated, with two curved solenidia, ω 1 thinner than ω 2, famulus ε short ( Figure 9A ). Tibia I with two solenidia, ϕ 1 long, protruding beyond tarsal claw, ϕ 2 distinctly smaller. Most setae on legs curved, segments of legs, setae and basal parts of solenidia covered with granular cerotegument, except for claw and distal setae surrounding claw.

Summary of ontogenetic transformations

During ontogeny five pairs of setae are present on the prodorsum of Al. setosus , including a sensillus. Setae ro and le remain rather long and curved in all instars, whereas seta in is long in the larva, and gets short in the nymphal stages and adult. Seta ex is rather long in the larva, and gets relatively shorter in the nymphs and adult. The bothridium is rounded in all instars, but in the larva is relatively large, in the nymphs is smaller, and in the adult becomes large again. The sensillus is setiform in all instars.

The larva has 12 pairs of gastronotal setae, as do the nymphs (d -series lost, p -series added). The adult loses eight pairs of notogastral setae (c -, l -series, h 2 and h 3), so that only four pairs of setae remain (h 1 and p -series, Table 2). The formula of gastronotal setae is 12-12-12-12-4 (larva to adult), formulae of coxisternal setae are: 3-1-2 (larva), 3-1-2-1 (protonymph), 3-1-3-2 (deutonymph) and 3-1-3-3 (tritonymph and adult). In the larva, seta 1c is scaliform and covers Claparéde’s organ. The formula of genital setae is 1-4-6-7 (protonymph to adult), and that of segments PS–AN is 23333-0222-022.

Distribution and ecology

Aleurodamaeus setosus is considered a Palaearctic meridional species ( Subías 2004, 2011). Pérez-Íñigo (1972) found it in Canary pine forest litter ( Pinus canariensis C. Smith ), between Vilaflor and El Medano (Tenerife Island, Spain), and in several habitats of Los Monegros (Aragón, Spain) under rosemary ( Rosmarinus officinalis L.) and mosses ( Pleurochaetes squarrosa , Salsola vermiculata and Salsola venniculata ), but this species was most abundant in shrubby Russian thistle ( Salsola vermiculata L.) (Pérez-Íñigo 1995). Moraza and Peña (2005) found Al. setosus as frequent (23% of total 128 samples) in several habitats on Tenerife Island, but it was most abundant under herbs, and relatively abundant under Canary pine trees and evergreen bush ( Laurus sp. ). Melamud et al. (2007) recorded this species from litter in dense evergreen Palestine oak ( Quercus calliprinos Webb. ) and deciduous Pistacia palaestina Boiss. at the valley bottom, and on the north-facing slope of Mount Carmel ( Israel). Akrami (2007) found it in soil under fruit trees in Iran, while Sergienko (1980) recorded it from nests of bank swallows ( Riparia riparia L). Our studied material from Turkey was from mosses on large stones in steppe vegetation, in a suburb of Kayseri (38 ◦ 40.30 ′ N, 035 ◦ 31.57 ′ E, 1274 m above sea level). This is a new record for the fauna of Turkey ( Özkan et al. 1988, 1994; Erman et al. 2007).

Figures

Figure 1. Aleurodamaeus setosus, adult, dorsal aspect, scale bar 100 µm. Legs partially drawn. Explanation of labels in text.

Figure 2. Aleurodamaeus setosus, adult, scanning electron micrographs. (A) Dorsal aspect; (B) lateral aspect; (C) posterior part of notogaster; (D) granules of cerotegument.

Figure 3. Aleurodamaeus setosus, adult, scanning electron micrographs. (A) Proterosoma, lateral aspect; (B) hysterosoma, lateral aspect; (C) ventral aspect; (D) anogenital region.

Figure 4. Aleurodamaeus setosus, adult, scale bars 100 µm. (A) Lateral aspect; (B) anogenital region. Legs partially drawn. Explanation of labels in text.

Figure 5. Aleurodamaeus setosus, larva, dorsal aspect, scale bar 100 µm. Legs partially drawn. Explanation of labels in text.

Figure 6. Aleurodamaeus setosus, scale bars 50 µm. (A) Anal region of larva; (B) anogenital region of protonymph. Explanation of labels in text.

Figure 7. Aleurodamaeus setosus, anogenital region, scale bars 50 µm. (A) Deutonymph; (B) tritonymph. Explanation of labels in text.

Figure 8. Aleurodamaeus setosus, tritonymph. (A) Dorsal aspect, legs partially drawn, scale bar 100 µm; (B) posterior part of hysterosoma, lateral aspect. Explanation of labels in text.

Figure 9. Tarsus I and part of tibia I of tritonymph, scale bars 20 µm. (A) Aleurodamaeus setosus, paraxial aspect; (B) Licnodamaeus costula, fragment of tarsus with solenidia; (C) L. costula, paraxial aspect; (D) Licnobelba latiflabellata, fragment of tarsus with solenidia; (E) L. latiflabellata, paraxial aspect. Explanation of labels in text.