Dichromothrips priesneri (Hood, 1938)

Thripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 8-segmented antenna, segments III and IV with forked sense cone, terminal segments V-VIII
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Fore wing, fore wing distal region
Fig. 6: Sternites VI and VII
Fig. 7: Tergites VI-VIII
Fig. 8: Tergites VIII and IX, VIII with posteromarginal comb
Fig. 9: Tergites IX-XI

Dichromothrips priesneri breeds on the leaves and flowers of orchids. Both sexes macropterous; body color dark brown with bright vermilion internal pigmentation in thorax and abdomen; tarsi and apices of tibiae yellow; antennal segments I & II dark brown with vermilion pigmentation, III-VIII paler than I & II and without internal pigmentation; fore wings dark brown with a nearly colorless sub-basal area. Antennae 8-segmented; segments III & IV with apex narrowed and long forked sense cone (Fig. 1). Head distinctly wider than long; with 2 pairs of ocellar setae, pair I absent, pair III anterolateral to ocellar triangle (Fig. 2). Pronotum with transverse lines of sculpture near anterior margin; with 1 pair of elongate posteroangular setae (Fig. 3). Meso- and metafurca with median spinula. Metanotal median area transverse striate at anterior, but scarcely sculptured postero-medially; median setae arising behind anterior margin; campaniform sensilla present (Fig. 4). Mid and hind tarsi 2-segmented. Fore wing first vein with 2 setae distally; second vein with complete row of 12-14 setae (Fig. 5). Tergites without sculpture medially, but lateral thirds with many transverse lines (Fig. 7); VIII with a complete comb of long microtrichia and a group of microtrichia anterolateral to spiracles (Fig. 8); X without longitudinal split (Fig. 9). Sternites without discal setae; sternite VII with 2 pairs of median setae arising in front of posterior margin (Fig. 6).
Male tergite IX with no stout dorsal setae, but lateral and posteroangular setae sometimes stout; sternites III-VII usually with paired oval or round glandular areas which sometimes fuse medially.

The genus Dichromothrips Priesner, 1932
This genus includes nearly 20 described species from orchids in the Old World tropics, and an identification key to 14 of these is given by Mound (1976). Species within this genus generally have 8-segmented antennae, antennal segments III & IV with apex narrowed and long forked sense cone, 1 pair of long pronotal posteroangular setae (with the exception of Dichromothrips corbetti), a well developed endofurca spinula on the metathorax, a long and regular comb of microtrichia on tergite VIII, all of them lack ocellar setae I, and the metanotum is never longitudinally striate (Mound 1976; Mound & Kibby 1998).

Dichromothrips priesneri is similar to Diarthrothrips coffeae and Scolothrips rhagebianus in having 8-segmented antennae with forked sense cone on segments III and IV, meso- and metasternal furca with median spinula, in lacking regular rows of fine microtrichia on lateral thirds of tergites, and lacking ctenidia laterally on tergites V-VIII. Compared to Dichromothrips priesneri, Diarthrothrips coffeae and Scolothrips rhagebianus possess 2 pairs of elongate posteroangular pronotal setae, 3 pairs of ocellar setae on head, and tergite VIII without a posteromarginal comb of microtrichia. Whereas Dichromothrips priesneri has 1 pair of elongate posteroangular setae on pronotum, 2 pairs of ocellar setae on head, and tergite VIII with a complete posteromarginal comb of long and slender microtrichia.

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take less than one week to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather (Lewis 1973).

Host plants

Vector capacity
None identified, but possible mechanical distribution of phytopathogenic fungi and bacteria.

Damage and symptoms
-

Detection and control strategies
-

Biogeography

Africa. Cameroon (Ossidinge).

Hood JD (1938). A new subgenus and species of Thysanoptera from the Cameroons. Proceedings of the Biological Society of Washington. 51: 11-14

Lewis T (1973). Thrips: their biology, ecology and economic importance. Academic Press Inc., London Ltd., 349 pp

Moritz G (2006). Thripse. Pflanzensaftsaugende Insekten, Bd. 1, (1. Auflage). Westarp, Hohenwarsleben, 384 pp. ISBN-13: 978 3 89432 891 7

Moritz G, Morris DC & Mound LA (2001). ThripsID - Pest thrips of the world. ACIAR and CSIRO Publishing Collingwood, Victoria, Australia, CDROM ISBN 1 86320 296 X

Moritz G, Mound LA, Morris DC & Goldarazena A (2004). Pest thrips of the world - an identification and information system using molecular and microscopical methods. Centre for Biological Information Technology, University of Queensland, Australia, CDROM ISBN 1 86499 781 8

Mound LA (1976). Thysanoptera of the genus Dichromothrips on Old World Orchidaceae. Biological Journal of the Linnean Society. 8 (3): 245-265

Mound LA & Kibby G (1998). Thysanoptera: An identification guide, (2nd edition). CAB International, Wallingford and New York, 70 pp