Caliothrips graminicola (Bagnall & Cameron, 1932)

Panchaetothripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 8-segmented antenna, segments III and IV with forked sense cone
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Head and pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Meso- and metasternum with lyre-shaped furca
Fig. 6: Fore wing, distal region of fore wing
Fig. 7: Tergites II-IV
Fig. 8: Tergites IV-VI
Fig. 9: Sternites V-VII
Fig. 10: Tergites VIII and IX

Caliothrips graminicola is a grass feeding pest. Female macropterous; body dark brown; all tarsi and bases and apices of tibiae yellow; antennal segments III & IV yellow with apical half light brown, V mainly yellow with apex shaded (Fig. 1); fore wings brown, with two white cross bands, sub-basally and sub-apically, also variably pale on anterior part of median dark band, extreme apex dark (Fig. 6). Antennae 8-segmented; segments III & IV with long forked sensorium, VIII at least twice as long as VII (Fig. 1). Head not constricted at base (Fig. 2). Pronotum without long setae, with irregular longitudinal reticles and many markings within each reticle (Fig. 3). Metanotum irregularly reticulate, one pair of major setae near anterior margin (Fig. 4); metafurca elongate and lyre-shaped (Fig. 5). Mid and hind tarsi elongate but 1-segmented; hind coxae with coiled internal apodeme. Fore wing first vein close to or fused to costal vein, second vein with about 5 setae; costal cilia shorter than costal setae (Fig. 6). Tergites lateral thirds with widely-spaced transverse lines and many markings between these (Fig. 7 and 8); tergite VIII with craspedum medially, tooth-like microtrichia laterally; median split on X about half as long as tergite (Fig. 10). Sternites with transverse reticulation (Fig. 9).
Male: tergite IX with 3 pairs of stout setae medially; sternites IV-VII with small transverse glandular area (rudimentary sternal gland on sternite III).

The genus Caliothrips Daniel, 1904
The genus Caliothrips currently includes more than 20 species. Members of this genus are dark brown, head and pronotum with a heavy net-like sculpture and with internal markings inside each reticle. Head without neck and dorsal ridge. Fore wings banded (usually dark with pale areas) and antennae with 8 segments, and forked sense cone on antennal segments III & IV. Most of the species in this group are found living in grasses and legumes (Mound & Kibby 1998).

Caliothrips graminicola, Caliothrips phaseoli and Caliothrips sudanensis - all of them have tergites with transverse striate lines in lateral thirds, Caliothrips graminicola with many markings between these lines, Caliothrips phaseoli with few markings present in anterior half of each tergite and Caliothrips sudanensis without markings in between. Furthermore, pronotum of Caliothrips graminicola is always with irregular longitudinal reticulations, in Caliothrips phaseoli and Caliothrips sudanensis the reticulations are in parts transverse. Tergites of other species (Caliothrips fasciatus and Caliothrips impurus) have usually polygonal reticulations and numerous internal wrinkles on lateral thirds. Caliothrips fasciatus is the only species sculptured on pronotum with mainly equiangular reticulations (other species with irregular longitudinal reticulations). Compared to Caliothrips sudanensis with pale extreme apex on fore wings, other species have a dark extreme apex. In Caliothrips fasciatus and Caliothrips graminicola the forked sense cone on antennal segment IV scarcely extending beyond base of segment V, whereas in Caliothrips impurus, Caliothrips phaseoli, and Caliothrips sudanensis the forked sense cone on antennal segment IV extends to a point at least a third to base of segment V.
Members of Caliothrips can be recognised by their reticulate sculpture that bears internal markings. Only Retithrips syriacus also has complex markings within each of the reticles, and fore wings bearing anteromarginally 3 curious blister-like callosities and minute setae. Compared to the closely related genera Hercinothrips and Selenothrips, the head of Caliothrips species is not constricted into a neck. Hercinothrips has 2-segmented tarsi (Caliothrips and Selenothrips with 1-segmented tarsi), and in Selenothrips the hind margin of tergite VIII has a complete comb of long teeth, the pronotum has a transverse striate sculpture and the metanotum a dominant sculptured triangle medially (in Caliothrips and Hercinothrips tergite VIII posteromarginal comb of microtrichia is only present laterally, pronotum with reticulate sculpture, and metanotum without dominant sculptured triangle medially).

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take about 15 days (Lewis 1973) to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather.

Host plants
Grasses (Poaceae): junglerice (Echinochloa colona), lemongrass (Cymbopogon sp.), sorghum.

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

Damage and symptoms
-

Detection and control strategies
-

Biogeography

Old World tropics, Australia, Yemen, Africa. South Africa (Gauteng: Pretoria District, KwaZulu-Natal: St. Lucia Estuary), Sudan (Wad Medani), Zimbabwe (Mount Silinda, Chipinge).

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Faure JC (1957). South African Thysanoptera - 6. Journal of the Entomological Society of Southern Africa. 20 (1): 79-105

Faure JC (1962). Thysanoptera of Africa - 7. Entomologisk Tidskrift. 83 (1-2): 4-43

Girault AA (1927). Thysanoptera nova australiensis, II (paper No. 38). Published privately, Brisbane, 2 pp

Hood JD (1927). New neotropical Thysanoptera collected by C. B. Williams. II. Psyche. 34 (6): 230-246

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

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

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

Palmer JM, Mound LA & Du Heaume GJ (1989). 2. Thysanoptera, 73 pp. In Betts CR [ed.], CIE Guides to insects of importance to man. CAB International, Wallingford, Oxon, UK

Wilson TH (1975). A monograph of the subfamily Panchaetothripinae (Thysanoptera: Thripidae). Memoirs of the American Entomological Institute. 23: 1-354

zur Strassen R (1960). Catalogue of the known species of South African Thysanoptera. Journal of the Entomological Society of Southern Africa. 23 (2): 321-367