Dolichothrips indicus (Hood)

Mound, Laurence A. & Okajima, Shûji, 2015, Taxonomic studies on Dolichothrips (Thysanoptera: Phlaeothripinae), pollinators of Macaranga trees in Southeast Asia (Euphorbiaceae), Zootaxa 3956 (1), pp. 79-96 : 90-91

Dolichothrips indicus (Hood)

( Figs 16 , 21, 22, 23 , 36 )

Neoheegeria indica Hood, 1919: 96 .

Dolichothrips pumilus Priesner, 1935: 362 . Syn.n.

Dolichothrips (Dolicholepta) rambhutanae Ananthakrishnan, 1960: 572 .

Dolichothrips nesius Stannard, 1961:457 . Syn.n.

Hood described indicus from specimens collected by Ramakrishna from shoots of Ailanthus (Simaroubaceae) at Coimbatore, southern India. Three females are listed below that were collected and identified by Ramakrishna as this species, and these are probably part of the original series. In describing this species Hood stated that the third antennal segment bears only two sense cones, and this statement was repeated by Stannard (1961). However, the Ramakrishna specimens listed here clearly have three sense cones on the third segment, and presumably these specimens include the “ syntype ” mentioned by Bhatti (1978) as having three sense cones. Moreover, this condition was confirmed on Hood’s holotype of indica by Greg Evans of USDA APHIS, Beltsville, who successfully photographed in different focal planes all three sense cones.

Hood described the postocular setae of indicus as “dilated at tip”, however this dilation is weak and less than the width of the seta near its base. The mid and hind tibiae are brown with the apex yellow, but the length of this yellow band is shorter than the distal width of a tibia. In contrast, the male listed below from Mallotus and identified as indicus by Ananthakrishnan has the postocular setae blunt at the apex. This male has the mid and hind tibiae similar in colour to the type series, and setae S2 on tergite IX are stout and longer than the iS setae. The female listed below from Rambhutan was labelled by Ananthakrishnan as rambhutanae , but this has finely pointed postocular setae, and the dark brown mid and hind tibiae are scarcely paler at the apex. In discussions about this variation, Dr Kaomud Tyagi of Kolkata commented (in litt. ii.2015) “I have checked eight specimens of Dolichothrips indicus , collected from Jasminum sambac , in which apices of postocular setae are blunt in six specimens but nearly pointed in two specimens. The colour of mid and hind tibia is brown with extreme apex yellow, this yellow area wider than long.”

Priesner described pumilus from Taiwan from an unspecified number of specimens. He did not designate any types, although someone subsequently has added a red holotype label to the slide listed below that bears the three original specimens. The mid and hind tibiae of these specimens are uniformly brown with the apex faintly paler but not clearly yellow. The female is without antennae, and has postocular setae that are bluntly pointed. One of the males has lost many of the major setae, including the postoculars, but has antennal segment VII almost uniformly dark brown. The second male has the postocular setae almost pointed, but antennal segment VII is largely yellow with brown shading in the apical third. Both males have the tergite IX setae S2 slightly shorter and stouter than the iS pair of setae.

Stannard, in describing nesius , referred to a female holotype deposited in the Bishop Museum, but he did not label as holotype either of the two specimens listed below from that museum. F. Bianchi placed a label on the reverse of both slides, and indicated that one female was probably the holotype, and that the other specimen was the “male allotype ”. However, this second specimen is actually a female. These two females were mounted into Hoyers Mountant, and by 2014 the mountant had dried out completely, crushing the specimens and obscuring all structural and colour characteristics. The putative holotype was remounted into fresh Hoyers Mountant, because it proved impossible to dissolve the old mountant and rescue the specimen. The mountant around the second female was dissolved after prolonged treatment in warm water, and the specimen was remounted into Canada balsam. It was thus possible to confirm the following character states: mid and hind tibiae with apices extensively yellow, the yellow area longer than the width of the tibial apex. The postocular setae of the holotype are broadly blunt at the apex, not pointed, but the postocular setae on the second female were lost during remounting. Stannard, in describing nesius , also mentioned that he had studied specimens from Sri Lanka.

From the above, it seems that, although some specimens of indicus from India have the postocular setae weakly dilated at the apex, the condition of these setae is variable among Indian populations. All other available specimens have the postocular setae blunt to pointed at the apex. The apical colour of the mid and hind tibiae is even more confusing. The type specimens of nesius have the most extensive yellow area, and the type specimens of pumilus have the least yellow. But specimens from other parts of the world suggest that there is almost continuous variation between these two extremes. Moreover, the chaetotaxy of the lateral areas of tergites II–IV varies considerably ( Figs 21–23 ), not only between specimens from single localities, but also on the left and right sides of the same individual. Considering these patterns of variation the conclusion is that indicus is a variable, polyphagous and widespread species, with both nesius and pumilus best considered synonyms in the absence of more secure data.

This species shares with reuteri the unusual character state of having the mesonotal lateral setae short and acute, although this condition is also found in two species that have the pronotum strongly sculptured, chikakoae and eriae . The mid and hind tibiae of reuteri , and its synonym flavipes , are considered to be consistently entirely yellow. Thus the specimens from southern Japan mentioned by Okajima (2006) as having these tibiae variable in colour are here regarded as indicus , as are the specimens from French Polynesia identified as flavipes in Hoddle et al. (2008).

Specimens examined. INDIA: 3 females (from type series?) from Ailanthus shoots, Ramakrishna coll. 29(a) ; 4 females without data, labelled by R. S.Bagnall; Madras , 1 female from Cassia , 9.vi.67 ( TNA54 ); Sirumalai , 1 male from Mallotus , 27.vii.67 ( TNA54 ); Kallar, from inflorescence of Rambhutan, 9.v.1959, in BMNH .

GUAM, Mt Lamlam,? holotype female of nesius and one paratype female, from young leaves of Melastoma marianum , Feb. 1958, N. Krauss, in Bernice P. Bishop Museum, Honolulu.

TAIWAN, Nisui , 1 female, 2 male syntypes of pumilus , from Diospyrus discolor , 1.xi.1928, R . Takahashi , in SMF .

HAWAIIAN ISLANDS, coll. F. Calvert: HAWAII, Keeau, 11 females from Macaranga tanarius , 20.v.2014; Kona, 4 females from Macaranga tanarius , 20.vi.2014; Hilo, 8 females from Hibiscus tiliaceus , 20.v.2014, 4 females from Mangifera indica , 20.v.2014, 2 females from Murraya koeigii , 21.vi.2014, 3 females from Acalypha hispida , 29.i.2010. OAHU, Waiamanalo, 8 females from Macaranga tanarius , 11.iii.2010, in ANIC. NEW CALEDONIA, Bouraille and La Foa, 2 females, 1 male from Hibiscus tiliaceus , i.2012, in ANIC. FRENCH POLYNESIA, Moorea, Rurutu, Tahiti, 5 females from Persea , Hibiscus and Musa , ix.2004, in ANIC. JAPAN, Okinawa Island, 18 females from Macaranga tanarius , 12.iv.2012, in ANIC. BARBADOS, 3 females from cotton, 14.i.2007, in ANIC. BRAZIL, Maranhão, São Luis, 3 females from Acacia , 22.vii.2011.

Figures

FIGURES 7 – 16. Dolichothrips species. Head & pronotum 7 – 9: (7) macarangai; (8) fialae sp. n.; (9) utae sp. n. Mesonotum and metanotum 10 – 15: (10) chikakoae sp. n.; (11) eriae sp. n.; (12) fialae sp. n.; (13) utae sp. n.; (14) franae sp. n.; (15) reuteri; (16) indicus mesonotum and pelta.

FIGURES 17 – 33. Dolichothrips species. (17) eriae sp. n. fore leg; (18) chikakoae sp. n. pelta, tergites II – III; (19) crassusensus tergites II – IV; (20) fialae sp. n. pelta, tergites II – III; (21) indicus (nesius holotype) tergites II – III; (22) indicus Syntype tergites II – IV; (23) indicus from Mo’orea, pelta, tergites II – III; (24) franae sp. n. tergites II – III. Pelta and tergites II – III 25 – 29: (25) eriae sp. n.; (26) longicollis; (27) macarangai; (28) utae sp. n.; (29) reuteri. Male pseudovirga 30 – 33: (30) fialae sp. n.; (31) longicollis; (32) macarangai; (33) reuteri.

FIGURES 34 – 38. Dolichothrips species mouth cone, prosternum and mesopresternum (34) fialae sp. n.; (35) franae sp. n.; (36) indicus; (37) longicollis; (38) reuteri.