Frankliniella borinquen Hood, 1942

Thripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: Antenna, scape, pedicel and first segment of flagellum, segments IV-VIII
Fig. 2: Special shape of pedicel
Fig. 3: Head dorsal with ocellar triangle
Fig. 4: Pronotum
Fig. 5: Metanotum
Fig. 6: Forewing, mid and distal region
Fig. 7: Sternites IV and V
Fig. 8: Tergite VIII
Fig. 9: Adult female

Frankliniella borinquen breeds on a wide range of plants e.g. beans and cruciferous plants. In Kenya and Uganda, this species is very closely associated with Tithonia diversifolia. Both sexes fully winged. Body color nearly uniformly pale yellow, deepest in pterothorax; legs paler than body; major setae dark brown; antennal segments I & II whitish yellow, III & IV pale yellow basally and brown apically, V pale with faint shades at base and at tip, VI yellowish brown at base otherwise like VII & VIII brown; fore wings pale (Fig. 9). Antennae 8-segmented; segments III & IV with forked sense cone, segment III pedicel distal to basal ring with a convex swelling and ill-defined collar, segment VIII equal in length to or less shorter than segment VII (Fig. 1). The pedicel between the II and III antennal segment is swollen, with edged ring surmounted by a distinctive swelling and a slightly flared collar (cup and saucer shaped) (Fig. 1, 2). Head wider than long; 3 pairs of ocellar setae present, pair III about as long as distance between the midpoints of hind ocelli and arising on anterior margins of or just within anterior margins of ocellar triangle; postocular setae pair I present, pair IV longer than other postoculars and as long as distance between hind ocelli (Fig. 3). Pronotum with 4-5 pairs of elongate setae (1 pair anteromarginally, 1 pair anteroangularly, 2 pairs posteroangularly and 1 pair of moderately elongate posteromarginal submedian setae) (Fig. 4). Mesofurca with spinula. Metanotal median area transverse at anterior and with irregular reticulations on posterior half; median setae longer than lateral setae and arising at anterior margin; campaniform sensilla present (Fig. 5). Mid and hind tarsi 2-segmented. Fore wing with 2 complete rows of veinal setae (Fig. 6). Tergites V-VIII with paired ctenidia laterally, ctenidia sometimes weakly developed on IV, on VIII anterolateral to spiracle; posteromarginal comb on VIII complete, with short microtrichia arising from triangular bases, rarely with 1 tooth missing (Fig. 7 and 8). Sternites III-VII without discal setae; median setae of sternite VII arising at or close to posterior margin.
Male similar to female; sternites III-VII with transverse glandular area.

The genus Frankliniella Karny, 1910
This genus is mainly known from the New World and contains about 230 species, many of them from the Neotropics (Mound & Marullo 1996, Cavalleri & Mound 2012). Some species are widely known as crop pests - Frankliniella occidentalis, Frankliniella intonsa, Frankliniella schultzei (all of them vectors of tospoviruses) and Frankliniella williamsi. The members in this genus are sometimes quite difficult to separate from one another and the classification has been in flux with many species later synonymized in association with color variations. They most have 3 pairs of well developed ocellar setae, 8-segmented antennae with segments III and IV having forked sense cones, usually 4-5 pairs of elongate pronotal setae (1 pair anteromarginally, 1 pair anteroangularly, 2 pairs posteroangularly, and 1 pair of moderately elongate posteromarginal submedian setae S2 which are longer than median seta S1), metanotal median setae arising at anterior margin, when present wings with complete rows of setae on the wing veins, paired ctenidia laterally on tergites V-VIII with those on VIII anterolateral to the spiracles, no discal setae on sternites, and the males are generally smaller and paler than the females (Mound & Marullo 1996; Stannard 1968).

Frankliniella borinquen differs from other species of Frankliniella by the shape of pedicel of antennal segment III (Frankliniella borinquen has a pedicel swollen, with edged ring surmounted by a distinctive swelling and a slightly flared collar; Frankliniella occidentalis as well as Frankliniella schultzei and Frankliniella williamsi have a simple pedicel), and by the length of the last antennal segment (Frankliniella borinquen with antennal segment VIII equal in length to or shorter than segment VII; other three species with antennal segment VIII longer than segment VII). (The pale colouration of antennal segment V as compared to other segments is also a typical character state differentiating the species, Frankliniella occidentalis, Frankliniella schultzei - light brown to brown as compared to brownish IV and VI; Frankliniella borinquen- V pale compared to brownish IV and VI; Frankliniella williamsi - pale V as compared to an equally pale IV and brownish VI). The species is very similar to Frankliniella occidentalis, in both ocellar setae III on head are about as long as distance between external margins of hind ocelli (Frankliniella occidentalis) or between the midpoints of hind ocelli (Frankliniella borinquen), whereas in Frankliniella schultzei and Frankliniella williamsi they are about as long as distance between hind ocelli (in some pale forms of Frankliniella schultzei the ocellar setae III length should be shorter than between the midpoint of hind ocelli). In Frankliniella borinquen as well as Frankliniella schultzei the length of postocular setae IV are about as long as distance between hind ocelli (in Frankliniella occidentalis postocular setae IV are longer and in Frankliniella williamsi distinctly shorter than distance between hind ocelli). In Frankliniella borinquen, Frankliniella occidentalis and Frankliniella williamsi ocellar setae III arising on anterior margins of or just within anterior margins of ocellar triangle, and campaniform sensilla on metanotum are present (only Frankliniella schultzei with ocellar setae III arising very close together between anterior margins of hind ocelli either on or behind the tangent across the anterior margins of the hind ocelli, and without metanotal campaniform sensilla). Like in Frankliniella occidentalis, females of Frankliniella borinquenpossess a complete posteromarginal comb of short microtrichia arising from triangular bases on tergite VIII (in Frankliniella occidentalis those microtrichia short or long). In constrast, Frankliniella williamsi has tergite VIII always with posteromarginal comb of long and fine, closely spaced microtrichia on broadly triangular bases, and Frankliniella schultzei has a comb weakly developed or complete absent. Compared to Frankliniella williamsi which has 1 or 2 median discal setae in addition to marginal setae on sternite II, other species of Frankliniella possess sternite II without median discal setae.
Species of the genus Frankliniella are similar to species of Thrips, Stenchaetothrips, Microcephalothrips abdominalis, Larothrips dentipes and Fulmekiola serrata, in having tergites V-VIII which bear a pair of ctenidia laterally, but in those species ctenidia of the tergite VIII lie posteromedial to the spiracle, whereas species of Frankliniella have ctenidia on tergite VIII which lie anterolateral to the spiracle. Compared to the species listed above without ocellar setae I on head, species of Frankliniella have 3 pairs of ocellar setae well developed.

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle for Frankliniella borinquen 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
Crops: amaranth, beans (broad bean, hyacinth bean), brocolli, cabbage, cassava, eggplant, green gram, kale, onion, pumpkin, sunflower, sweet potato, tomato.
Weeds: Achyranthes aspera, Ajuga remota, Bidens pilosa, Carthamus sp., Guizotia scabra, Hibiscus tiliaceus, Lantana camara, Ornithogalum sp., Tithonia diversifolia.

Damage and symptoms
Infestation with Frankliniella borinquen results in silvering and bleaching of leaves and flowers. Severe infestation can lead to drying of Tithonia diversifolia plants.

Detection and control strategies
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Additional notes
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Life history
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Additional notes:
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Biogeography

Africa. Caribbean, Middle and North America. Kenya, Uganda.

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