Aeolothripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 9-segmented antenna, segments III and IV with linear sensoria, terminal dark segments V-IX
Fig. 2: Scape and pedicel of antenna
Fig. 3: Head dorsal with ocellar triangle
Fig. 4: 7-"segmented" maxillary palps
Fig. 5: Pronotum
Fig. 6: Meso- and metanotum
Fig. 7: Fore wing and distal region of fore wing
Fig. 8: Tergites II-IV
Fig. 9: Tergites V-VII
Fig. 10: Tergites VIII-XI

Allelothrips tenuicornis is a predator of other thrips and arthropods associated with grasses and cereals like sorghum and also on groundnuts. Female macropterous and with a wasp-like waist. Body color dark brown and with extensive red internal pigment; antennal segments I & II brown, II paler distally, III & IV white, V basally pale, VI-IX dark brown (Fig. 1 and 2); fore tibia distally and fore tarsi paler than mid and hind legs; fore wings with 3 dark transverse bands basally, medially, and apically (Fig. 7). Antennae 9-segmented, elongate; segment III exceptionally long and slender, and about 7-8 times as long as wide; segments IV & V subequal in length; length of segment V much shorter than VI-IX together; segments III & IV with simple linear, gently undulated sensory areas (Fig. 1 and 2). Head nearly as wide as long (Fig. 3), eyes prolonged ventrally; maxillary palps consist of 3 segments, although 3rd segment is subdevided into 5 to 6 pseudosegments (Fig. 4). Prothorax rectangular, without long setae (Fig. 5). Mesonotum minutely striate. Metanotum with a distinctive triangular area of striate sculpture, 1 pair of setae at anterior margin and 1 pair near posterior (Fig. 6). Tarsi 2-segmented, fore tarsus apically with stout recurved ventral hamus. Fore wing slender with apex rounded, cross veins prominent; costal margin with setae but no cilia (Fg. 7). Tergites with discal setae small; tergite X with pair of very small trichobothria (Fig. 8, 9 and 10). Sternites II-VII each with about 4 pairs of posteromarginal setae and 1-4 discal setae laterally. Sexually dimorphic.
Male smaller than female; antennal segment III distally and segments IV-IX grey-brown; abdomen slender.

The genus Allelothrips Bagnall, 1932
7 species are listed in this genus, 6 from Africa and 1 from India. The genus was defined largely on the number of maxillary palp segments, and the 3 nominal genera were separated on the fact that the maxillary palpi were 2-segmented (Arhipidothrips), 3-segmented (Pseudoaeolothrips) and 7- or 8-segmented (Allelothrips, Fig. 4) (Mound 1968). Now, all of them are united to the genus Allelothrips. Members of this genus have 9-segmented antennae, the metanotum with a distinctive triangular area of striate sculpture, and the antennal sensoria are linear and simple, sometimes gently undulated, but without scalloped margins (Mound & Kibby 1998).

Allelothrips tenuicornis as well as Allelothrips vilardeboi differs from other species of Allelothrips in the length of antennal segment V of female, that is much shorter than VI-IX together (other species with antennal segment V that is subequal to VI-IX together in females). Most of Allelothrips species have a mainly brown body color (except for Allelothrips talithae with yellow or light brown body color), fore wings with 3 dark transverse bands - basally, medially, and apically with extreme apex dark (except for Allelothrips vilardeboi with extreme apex pale), antennal segment IV of female is at least basally or completely pale (except for Allelothrips cincticornis and Allelothrips vilardeboi with antennal segment IV completely brown or dark brown), and antennal segments VI-IX have a brown to dark brown color (except for Allelothrips cincticornis with segments VI-IX pale). The species is similar to Allelothrips cameroni in having antennal segments I & II with brown color, at least in part (in contrast the color of antennal segments I & II of Allelothrips brunneus, Allelothrips cincticornis, Allelothrips talithae and Allelothrips vilardeboi is pale). Allelothrips tenuicornis as well as Allelothrips brunneus exhibit antennal segment III that is 7-8 times as long as wide (compared to Allelothrips cincticornis and Allelothrips talithae with antennal segment III that is 9-10 times as long as wide; Allelothrips cameroni and Allelothrips vilardeboi with antennal segment III that is only 5-6 times as long as wide).
Species of Allelothrips differ from Franklinothrips and Aeolothrips in having a metanotum with a distinctive triangular area of striate sculpture (Aeolothrips fasciatus with metanotum median area with irregular equiangular reticulation; species of Franklinothrips without sculpture medially). Furthermore, Franklinothrips species have antennal sensoria on segments III & IV that are linear with scalloped margins (those of Allelothrips species and Aeolothrips fasciatus are linear and simple but without scalloped margins), and 2 pairs of posteromarginal setae on sternites III-VI and 4 pairs of posteromarginal setae on sternite VII (Allelothrips species possess 4 pairs of posteromarginal setae on sternites III-VII; Aeolothrips fasciatus with 4 pairs of posteromarginal setae on sternites III-VII, and 2 pairs of supernumerary setae anterior to marginal setae S1 and S2 on sternite VII). Compared to Aeolothrips fasciatus, species of Allelothrips and Franklinothrips have discal setae laterally on sternites II-VII (Aeolothrips fasciatus without discal setae on sternites).

Host plants
The plants on which Allelothrips tenuicornis are found in association with prey are cereals and grasses like sorghum, and also groundnut.

Vector capacity
None identified

Damage and symptoms
-

Detection and control strategies
-

Additional notes
The species is very active and moves on plants with the antennae waving like a small Hymenopteron (Mound 1968).

Biogeography

West and East Africa. Senegal (Fété Olé), Sudan (Blue Nil Province, Wad Medani).

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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 Wissenschaften, Hohenwarsleben, 384 pp. ISBN 13: 978 3 89432 8917

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

Mound LA (1968). A review of R.S. Bagnalľs Thysanoptera collections. Bulletin of the British Museum (Natural History), Entomology. 11: 1-181

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

Palmer JM (1990). Identification of the common thrips of Tropical Africa (Thysanoptera, Insecta). Tropical Pest Management. 36 (1): 27-49

Pitkin BR & Mound LA (1973). A catalogue of West African Thysanoptera. Bulletin de ľInstitut Fondamental ďAfrique Noire, Série A. 35 (2): 407-449

Stannard LJ (1961). A new species of Allelothrips from South India, with notes on the synonymy and characteristics of the genus (Thysanoptera: Aeolothripidae). Bulletin of Entomology, Madras. 2: 9-11