Neoseiulus tunus ( De Leon, 1967 )

Ferragut, Francisco & Navia, Denise, 2022, The genus Neoseiulus Hughes (Mesostigmata: Phytoseiidae) in the Espinhaço Range, a great reservoir of biodiversity in Brazil, Zootaxa 5120 (4), pp. 523-542 : 536-538

Neoseiulus tunus ( De Leon, 1967)

Typhlodromips tunus De Leon, 1967: 29 .

Amblyseius tunus .— McMurtry & Moraes, 1989: 181.

Neoseiulus tunus .— Chant & McMurtry, 2003: 21.

Typhlodromips neotunus Denmark & Muma, 1973: 255 . Synonymy according to Cavalcante et al. 2017: 593.

Specimens examined. Eighteen females, three males on Tibouchina urvilleana (Melastomataceae) and one female on Tibouchina sp. (Melastomataceae) ; forest clump near Juquinha’s memorial, road MG-010, Serra do Cipó, 19º15’17”S, 43º33’10”W, 1354 m asl; 18 August 2011. One female on Lantana camara (Verbenaceae) ; Almadina, (Bahia), 14º47’47”S, 39º10’27”W, 1354 m asl; 14 January 2015 (Adeilma Carvalho coll.). Four females on unidentified Melastomataceae ; Ilha do Mel (Paraná), 25º32’25”S, 48º17’36”W, 5 m asl; 4 January 2009. Seven females on Miconia ligustroides (Melastomataceae) ; Canyon Guartelá (Paraná), 24º33’50”S, 50º15’21”W, 962 m asl; 7 January 2009.

Geographical distribution. Neotropical species reported from Argentina, Brazil, French Antilles, Jamaica, Perú and Trinidad.

Additional description (eight females). Dorsal shield 313 (306–317) long, 170 (166–174) wide. Dorsal setae of the series j -J, except j1 and j3, smooth; setae j1, j3, z2, z4, and s4 slightly barbed; setae Z1, S2, S4, and S5 smooth; setae Z4 and Z5 serrated. Length of j1 22 (20–23), j3 26 (25–27), j4 17 (14–18), j5 16 (15_17), j6 21 (19–22), J2 22 (20–23), J5 8 (7–9), z2 26 (24–27), z4 27 (25–29), z5 19 (18–20), Z1 25 (23–26), Z4 35 (33–37), Z5 50 (49–50), s4 34 (32–37), S2 31 (26–35), S4 27 (25–32), S5 21 (20–22). Sublateral setae r3 25 (23–26), R1 20 (18–21). Seven pairs of dorsal gland openings, some of them difficult to discern; gd1, gd2 and gd5 minute and punctiform, gd4, gd6 and gd8 small and elongate, gd9 medium-size and horseshoe-shaped. Peritremes narrow, extending near the bases of setae j1; 187 (186–188) long; internal groove with two lines of microvilli. Sternal shield distinctly broader than long, 66 (64–68) long, 78 (75–81) wide; anterior and posterior margins concave; presternal area sclerotised and granulate. Distance st1–st3 60 (59–64); st2–st2 64 (62–66). Epigynal shield 112 (107–115) long; distance st5–st5 59 (56–61). Ventrianal shield weakly striated transversally; length 108 (103–113), width at level of setae ZV2 78 (74–80), at level of anus 61 (59–64); distance between pre-anal pores 16 (13–21). Setae JV5 slightly barbed, 41 (38–44) long. Dentition of cheliceral fixed digit variable, from 8 to 11 teeth (always with two subapical teeth, followed by a variable comb of 6–9 teeth); movable digit tridentate. Genu II with eight setae (2 2/1, 2/0 1), genu III with seven setae (1 2/1, 2/0 1). Macrosetae on leg IV distally knobbed; on genu IV 19 (18–19), on tibia IV 18 (17–19), on basitarsus IV 35 (33–38) long.

Remarks. De Leon (1967) described briefly the species from a single female collected in the Caribbean island of Trinidad. Afterwards, Moraes et al. (2000) provided a more complete description with measurements of setae and other structures from the holotype and from females collected in several French Caribbean islands, and Guanilo et al. (2008b) were the first to mention that genu II has eight setae. Eventually, Cavalcante et al. (2017) presented detailed morphological information based on specimens from different parts of Brazil, pointing for the first time the number of dorsal solenostomes and proposing the synonymy between N. tunus and N. neotunus ( Denmark & Muma) (the assertion of these last authors that N. tunus has seven setae on genu II should be considered a mistake).

Measurements of setae and shields of females from Serra do Cipó agree well with those informed in the literature, with the exception of the dimensions of setae Z4, Z5 and S5, which are shorter. In particular, setae Z5 are noticeably shorter, not exceeding 50 µm, while other authors reported lengths between 63–80 µm ( Cavalcante et al. 2017; Kreiter et al. 2018).

The most striking differences between the examined specimens and the information reported in previous literature refer to the morphology of dorsal setae. Chant & McMurtry (2003) created the tunus species subgroup within the species group cucumeris to accommodate N. tunus , N. neotunus and N. plumosus ( Denmark & Muma), characterised by having the dorsolateral setae strongly barbed. The senior author of this work has examined females of N. tunus from different parts of Brazil (Almadina in the state of Bahia, Ilha do Mel and Canyon Guartelá in the state of Paraná and the mites collected in Serra do Cipó, state of Minas Gerais) reaching to the conclusion that the serration of these setae can be pretty variable. While specimens from Almadina and Ilha do Mel have all the dorsolateral setae except S5 and J5 serrate, some females from Canyon Guartelá show Z1, S4, S5 and J5 smooth whereas others have Z1 and S4 barbed and all the females collected in Serra do Cipó have setae Z1, S2, S4, S5 and J5 smooth and the remaining setae (except Z4, Z5, which are strongly barbed) smooth or with few barbs ( Figures 15 , 16 ). Recently, Ferreira et al. (2021) have reported morphological variations in this species depending on the diet. Females fed on the eriophyid mite Aculops lycopersici (Massee) showed significant longer dorsal setae, macrosetae of leg IV and width of the dorsal and ventrianal shields than females fed on the two-spotted spider mite Tetranychus urticae Kock. These authors did not mention or studied qualitative morphological traits as the setal serration.

Figures

FIGURE 15. A–D. Neoseiulus tunus, serration of dorsal setae Z1 and S2. A. setae Z1 and S2 smooth (Serra do Cipó, Minas Gerais); B. Z1 smooth, S2 barbed (Canyon Guartelá, Paraná); C. barbed Z1, serrated S2 (Canyon Guartelá, Paraná); D. barbed Z1, serrated S2 (Almadina, Bahia).

FIGURE 16. A–B. Neoseiulus tunus, smooth dorsal setae S4 and S5. A. female from Canyon Guartelá, Paraná; B. female from Serra do Cipó, Minas Gerais.