Thrips (Mound and Masumoto, 2005)

Mound, Laurence A. & Nickle, David A., 2009, Species of the genus Thrips (Thysanoptera) from Peninsular Malaysia, with a checklist of recorded Thripidae, Zootaxa 2023, pp. 55-68 : 59-64

Key to the species of Thrips from Peninsular Malaysia

1. Sternites IV–VI with discal setae as well as posteromarginal setae ( Figs 27–28 )........................................................ 2

-. Sternites IV–VI with no discal setae, only with posteromarginal setae ..................................................................... 16

2. Pronotum with no prominent posteroangular setae ( Figs 13 , 21 )................................................................................. 3

-. Pronotum with 1 or 2 pairs of prominent posteroangular setae ................................................................................... 5

3. Sternites with at least 10 marginal setae ( Fig. 25 ); pleurotergites with discal setae ......................................... aspinus

-. Sternites with only 6 marginal setae ( Fig. 28 ); pleurotergites without discal setae ..................................................... 4

4. Pronotum with one pair of posteroangular setae about 15 microns long, clearly longer than discal setae ( Fig. 13 ); antennal segment VI uniformly brown ................................................................................................................. mirus

-. Pronotum with no posteromarginal or posteroangular setae longer than discal setae ( Fig. 21 ); antennal segment VI yellow in basal half ................................................................................................................................... hanifahi sp.n.

5. Pronotum with only 1 pair of long posteroangular setae ................................................................................. unispinus

-. Pronotum with 2 pairs of long posteroangular setae.................................................................................................... 6

6. Abdominal sternite VII with no discal setae ( Fig. 26 ) [forewing first vein setal row almost complete, at least with more than 8 setae on distal half] ................................................................................................................................. 7 -. Abdominal sternite VII with discal setae ( Fig. 27 ) [forewing first vein setal row never complete, usually with less than 8 setae on distal half]............................................................................................................................................ 9

7. Forewing clavus apical seta shorter than subapical seta (cf. Fig. 17 ) [forewing dark at base; metanotal sculptured reticles equiangular and with internal markings ( Fig. 12 )] ................................................................................. orientalis

-. Forewing clavus apical seta longer than subapical seta [forewing usually paler at base; metanotal reticles longitudinal or with no internal markings] ................................................................................................................................ 8

8. Metanotal reticles without, or with few, internal markings ( Fig. 15 ) ........................................................ parvispinus

-. Metanotal reticles with many internal markings................................................................................................. decens

9. Tergite VIII marginal comb absent or at least not developed medially ( Fig. 23 ) ....................................................... 10

-. Tergite VIII marginal comb complete ( Fig. 22 ).......................................................................................................... 11

10. Metanotum with some reticulation medially ( Fig. 7 ) ....................................................................................... leeuweni

-. Metanotum closely striate medially ( Fig. 16 ) ................................................................................................. vitticornis

11. Metanotal median setae arising at anterior margin ( Figs 4, 8 ) .................................................................................. 12

-. Metanotal median setae arising behind anterior margin ( Fig. 14 ) ............................................................................ 14

12. Pronotal posteroangular setae short, inner pair no longer than maximum width of fore tibia ................... melastomae

-. Pronotal posteroangular setae long, inner pair 1.1 to1.7 as long as maximum width of fore tibia ............................ 13

13. Forewing clavus apical seta longer than subapical seta ( Fig. 18 ); mesonotum with sculpture lines surrounding anterior pair of campaniform sensilla ( Fig. 8 )................................................................................................... hawaiiensis

-. Forewing clavus apical seta shorter than subapical seta ( Fig. 17 ); mesonotum with no sculpture lines surrounding anterior pair of campaniform sensilla ( Fig. 4 ) ................................................................................................... florum

14. Metanotal reticles usually with prominent internal markings ( Fig. 14 ) ............................................................. simplex

-. Metanotal reticles with no internal markings ( Fig. 3 ) ................................................................................................ 15

15. Abdominal pleurotergites with discal setae ........................................................................................................ facetus

-. Abdominal pleurotergites with no discal setae .............................................................................................. coloratus

16. Tergite VIII posteromarginal comb complete; females mainly yellow .................................................................... 17

-. Tergite VIII posteromarginal comb incomplete or absent; females mainly brown .................................................. 19

17. Head with ocellar setae III close together behind fore ocellus ( Fig. 20 ) .............................................................. flavus

-. Head with ocellar setae III posterolateral to fore ocellus ......................................................................................... 18

18. Metanotal sculpture lines converging near posterior margin ( Fig. 10 ) .................................................................. palmi

-. Metanotal sculpture lines irregularly sub-parallel, scarcely converging ( Fig. 1 ) ................................................ alatus

19. Forewing first vein with complete row of setae ................................................................................................ malloti

-. Forewing first vein setal row incomplete, with wide interval .................................................................................. 20

20. Forewing first vein with at least 12 basal setae .............................................................................................. javanicus

-. Forewing first vein with no more than 8 setae on basal half .................................................................................... 21

21. Metasternum with no more than 20 discal setae; antennal segments IV–V largely yellow ................................... alius

-. Metasternum with more than 20 discal setae; antennal segments IV–V brown ......................................................... 22

22. Femora yellow; metanotal reticles with few internal markings and only on anterior half of metanotum ( Fig. 11 ); male yellow .......................................................................................................................................................... levatus

-. Femora brown; metanotal reticles with internal markings on posterior as well as anterior half of metanotum ( Fig. 9 ); male brown ....................................................................................................................................................... morindae

Thrips alatus Bhatti. The original specimens of this species came from Uttar Pradesh in India, and also from Nepal. It is closely similar to Thrips palmi , of which it was described as “the Himalayan counterpart”. The metanotal sculpture differs slightly between these two, as indicated in the key above ( Figs 1, 10 ), but no other consistent differences have been observed. The species is here recorded from Malaysia on the basis of four females collected from Nasturtium flowers in the Cameron Highlands in March 2008. One female has also been studied from this same locality, collected in July, 1984 (in the Ewart Collection, Riverside, University of California).

Thrips alius Palmer. This species was described from banana flowers at Davao in The Philippines, and also recorded from the same plant in Yunnan, China. In the Rimba Ilmu at the University of Malaya, 7 females and 1 male were taken from the flowers of Alpinia speciosa (Zingiberaceae) in July 2006. The antennae of this species are unusually pale, with segments IV and V lightly shaded only in the apical third, and even the sixth segment shaded lightly only in the apical half. Similarly, the femora are extensively yellow with only light brown shading. The male is essentially yellow, with light brown shadings on the anterior margins of the head as well as on the tergites. A further Asian species that is closely similar in structure is Thrips pectiniprivus Priesner , known only from Krakatau. The type specimens of that species have been re-examined; the body of males is brown, and in females antennal segments IV–V are brown in the distal half with VI fully brown.

Thrips aspinus Mound and Masumoto. Described from mango flowers in the northeastern coastal region of Australia, a single female of this species has been studied from Kubang Pasu, Kedah, in northern Peninsular Malaysia, collected from mango flowers in December 2006. A closely related Oriental species that is likely to be found in Malaysia is T. subnudula (Karny) , but that has two pairs of pronotal posteroangular setae that are about twice as long as the pronotal discal setae ( Mound and Masumoto, 2005). Both species have numerous, irregularly arranged, discal setae on the sternites and the pleurotergites ( Fig. 25 ).

Thrips coloratus Schmutz. This is a widespread species across Asia , between Pakistan, Japan, New Guinea and northern Australia. It is usually not found in large numbers, and is particularly variable in colour and chaetotaxy ( Bhatti, 1980). Three females have been seen from Serdang , Selangor on different plants, and in the Natural History Museum, London there are three females from Kuala Lumpur. Also, in the Senckenberg Museum, Frankfurt, there are 12 females and one male from Macaranga flowers at Ulu Gombak near Kuala Lumpur. In females, the abdomen is generally yellow with a median brown mark on each tergite, but with the tenth tergite dark brown.

Thrips decens Palmer. This species is known only from a series of both sexes taken in the Genting Highlands, Malaysia, from Mussaenda flowers in October 1973. It is similar to T. javanicus in having a large number of setae at the base of the forewing first vein (10–14), but it has only a small number of discal setae on the sternites (0–6). The patterns of variation within and between populations require further study.

Thrips facetus Palmer. Known only from three females, two from the Cameron Highlands and one from Bangladesh, this species has the metanotal median pair of setae uniquely thickened, and the pronotal setae are also exceptionally robust. The number of abdominal pleurotergal discal setae varies from four to eight, and the median sternites have as many as 20 long discal setae.

Thrips flavus Schrank. Widespread across the northern hemisphere, this polyphagous species is similar to T. palmi in appearance, but has ocellar setae pair III close together behind the first ocellus ( Fig. 20 ). The metanotal sculpture lines form elongate reticles medially ( Fig. 6 ), and do not form an inverted arch at the posterior margin as is usual in T. palmi . The species is common in northern India, but a series of specimens has been seen from Malaysia, at MARDI, Serdang, Selangor, from Melastoma flowers in March 2008. There is also a series of both sexes in the Natural History Museum, London, taken from Gaultheria flowers at Tanah Rata.

Thrips florum Schmutz. The identity of this species, and its separation from the even more widespread species T. hawaiiensis , has been the subject of considerable study ( Palmer and Wetton, 1987; Bhatti, 1999). In addition to the two character states indicated in the key, specimens of T. florum usually have postocular setae pair II much shorter than pairs I and III. The three character state differences between these two species are not entirely consistent, and several specimens from different localities in Malaysia have been studied that have one or other of these characters intermediate between the two species.

Figures

FIGURES 25–28. Sternites of Thrips species. (25) T. aspinus sternites V–VI; (26) T. parvispinus sternites VI–VII; (27) T. vitticornis sternites VI–VII; (28) T. hanifahi sternites VI–VII.

FIGURES 1–13. Thrips species meso and metanota. (1) T. alatus; (2) T. alius; (3) T. coloratus; (4) T. florum; (5) T. hanifahi; (6) T. flavus; (7) T. leeuwenii; (8) T. hawaiiensis; (9) T. morindae; (10) T. palmi; (11) T. levatus (with pronotum); (12) T. orientalis; (13) T. mirus (with pronotum).

FIGURES 14–24. Thrips species. (14) T. simplex meso and metanotum; (15) T. parvispinus meso and metanotum; (16) T. vitticornis meso and metanotum; (17) T. florum forewing clavus; (18) T. hawaiiensis forewing clavus; (19) T. hanifahi head; (20) T. flavus head; (21) T. hanifahi pronotum; (22) T. coloratus tergites VII–VIII; (23) T. leeuwenii tergites VII–VIII; (24) T. hanifahi tergites VII–X.