Limothrips cerealium Haliday, 1836

Thripinae, Thripidae, Terebrantia, Thysanoptera

Figures

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

Limothrips cerealium causes damage on various Poaceae, including cereal crops like barley, maize, oats and wheat. Female macropterous; body color brown; tarsi yellow; antennal segment III light brown with pedicel yellow; fore wings light brown, sometimes with clear area at base. Antennae 8-segmented; III asymmetric with simple sense cone on slight prominence, segment IV with sense cone simple (Fig. 1). Head longer than wide; projecting in front of eyes; 3 pairs of ocellar setae present, pair III arise anterolateral to ocellar triangle; postocular setae small (Fig. 2). Pronotum with 1 pair of long posteroangular setae; posterior margin with 4-5 pairs of setae (Fig. 3). Metanotum with mainly equiangular reticulate sculpture; median setae arise behind anterior margin; campaniform sensilla present (Fig. 4). Meso- and metafurca without spinula (Fig. 6). Mid and hind tarsi 2-segmented. Fore and hind wings present, more than half as long as abdomen (macropterous) or absent (apterous), fore wing first vein with 2 setae on distal half; second vein with about 8 irregularly spaced setae (Fig. 5). Tergites with reticulation medially and 1 pair of campaniform sensilla close to posterior margin ; tergal craspeda and posteromarginal comb on tergite VIII not developed (Fig. 8); tergite X with 1 pair of stout thorn-like setae (Fig. 9). Sternites II-VII with 5-10 discal setae; without craspeda; median pair of marginal setae on sternite VII arise in front of margin (Fig. 7).
Male apterous; head without ocelli; pterothorax transverse without wing buds; tergite IX with 2 pairs of equally small stout setae on tubercles, 1 pair medially 1 pair laterally with elongate projection on one side; sternites III-VII with small sub-circular glandular area.

The genus Limothrips Haliday, 1836
The western Paleartic genus Limothrips currently includes 6-8 species that are considered to be valid (zur Strassen 2003). These all live on various grasses and breed in leaves and leaf axils. Although they came originally from Europe, 3 species are now widespread in temperate areas around the world. All of them are characterized as large dark thrips and can be distinguished from other genera in having a pair of stout thorn-like setae on tergite X and a typical helmet shape head. In addition, antennal segment II or III asymmetric and prolonged externally (Mound & Kibby 1998), the pronotum has 1 pair of long posteroangular setae, and males are usually apterous and have no ocelli.

The genus Limothrips is commonly associated with the genus Chirothrips and related genera Arorathrips, and similar in general appearance to some other grass living thrips, particularly to members of the genus Bregmatothrips. However, most of the structural similarities are possibly related in sharing a similar habitat on the leaves and flowers of grasses. Limothrips cerealium can be distinguished from species of these genera in having antennal segment II symmetric but III with external margin weakly prolonged. Usually species of the genus Chirothrips and Arorathrips mexicanus have an antennal segment II with external margin prolonged, but III symmetric except for Chirothrips guillarmodi with segment II and III symmetric, Chirothrips manicatus and Chirothrips pretorianus with external margin of segments II and III prolonged. Bregmatothrips dimorphus with antennal segments II and III more or less symmetric. Furthermore, Limothrips cerealium differs from species of other genera by the broadly rectangular pronotum with 1 pair of elongate posteroangular setae (species of Chirothrips and Arorathrips mexicanus with a trapezoidal pronotum and 2 pairs of elongate posteroangular setae; Bregmatothrips dimorphus with rectangular pronotum and 2 pairs of elongate posteroangular setae), and in having a pair of typical stout thorn-like setae on tergite X (in other species all setae on tergite X slender). Compared to other species, Limothrips cerealium has no craspedum at posterior margin of tergites or sternites, but discal setae on sternites II-VII (other species with a craspedum at posterior margin of tergites and/or sternites, but without discal setae on sternites II-VII), and 1-segmented mid and hind tarsi (others with 2-segmented mid and hind tarsi).

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The total life cycle at fluctuating temperatures lasts 30-35 days (Sharga 1933).

Host plants
Various Poaceae, including cereal crops: barley, sorghum, maize, oats, rye, wheat.

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

Damage and symptoms
Breeding on the leaves and in the florets and causing dead tips in various grasses and young cereal crops (Lewis 1997). Sometimes causing yield reduction in cereal crops, also reduced germination of barley seed produced for the brewing industry. Thrips-injured plants have leaf sheaths an blades silvered, oviposition scars on blades, ears with whitened spikelets, either empty or with shrivelled grains (Bailey 1948; Köppä 1970).
Its one among the few thrips species whose biting of humans have been found to cause dermal pseudo-delusory syndrome (Guarneri et al 2006).

Detection and control strategies
Limothrips cerealium is equally attracted to a range of colours including yellow, blue, green, black, red and white (Teulon and Penman 1992).

Biogeography
Cosmopolitan, worldwide in temperate regions. Algeria, Egypt, Libya, Morocco, Seychelles, South Africa (Western Cape: Stellenbosch).

Bagnall RS (1927). Contributions towards a knowledge of the European Thysanoptera - II. Annals and Magazine of Natural History, Zoology, Botany and Geology. (Serie 9) 19: 564-575

Bailey SF (1948). Grain and grass-infesting thrips. Journal of Economic Entomology. 41 (5): 701-706

Bailey SF (1957). The thrips of California Part I: Suborder Terebrantia. Bulletin of the California Insect Survey. 4 (5): 143-220

Bournier A & Bernaux P (1971). Haplothrips tritici Kurdj. et Limothrips cerealium Hal. agents de la moucheture des bles durs. Annales de Zoologie - Écologie Animale. 3: 247-259

Davies RG (1969). The skeletal musculature and its metamorphosis in Limothrips cerealium Haliday (Thysanoptera - Thripidae). Transactions of the Royal Entomological Society of London. 121: 167-233

Faulde MK, Sorhage B, Ksoll A & Tisch M (2007). Human Limothrips cerealium infestation associated with onychomycosis. Journal of the European Academy of Dermatology and Venereology. 21 (6): 841-843

Guarneri F, Guarneri C, Mento G & Ioli A (2006). Pseudo-delusory syndrome caused by Limothrips cerealium. International Journal of Dermatology. 45 (3): 197-199

Haliday AH (1836). An epitome of the British genera, in the order Thysanoptera, with indications of a few of the species. The Entomological Magazine. 3 (5): 439-451

Hartwig EK (1948). Six new species of South African Thysanoptera, with statistical analysis of measurements. Journal of the Entomological Society of Southern Africa. 11: 83-126

Hinds WE (1903). Contribution to a monograph of the insects of the order Thysanoptera inhabiting North America. Proceedings of the United States National Museum. 26 (1310): 79-242

Holtmann H (1962). Untersuchungen zur Biologie der Getreide-Thysanopteren - Teil 1. Zeitschrift für Angewandte Entomologie. 51 (1): 1-41

Holtmann H (1962). Untersuchungen zur Biologie der Getreide-Thysanopteren - Teil 2. Zeitschrift für Angewandte Entomologie. 51 (2): 285-299

Jenser G (2009). New Thysanoptera species from Syria, with descriptions of Limothrips syriacus sp. n. (Thripidae). Folia Entomologica Hungarica. 70: 81-85

Karny H (1914). Beitrag zur Thysanopterenfauna des Mediterrangebietes. Verhandlungen der Zoologisch-Botanischen Gesellschaft in Ãsterreich. 64: 50-60

Köppä P (1970). Studies on the thrips (Thysanoptera) species most commonly occurring on cereals in Finland. Annales Agriculturae Fenniae. 9: 191-265

Lewis T (1962). Effects of temperature and relative humidity on mortality in Limothrips cerealium Haliday (Thysanoptera) overwintering in bark. Annals of Applied Biology. 50 (2): 313-326

Lewis T (1963). Effect of weather on emergence and take-off of overwintering Limothrips cerealium Haliday (Thysanoptera). Annals of Applied Biology. 51 (3): 489-502

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

Lewis T (1997). Thrips as crop pests. CAB International, Wallingford, 740 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

Moritz G, O'Donnell C & Parrella M (2009). Pest thrips of North America. Centre for Biological Information Technology, University of Queensland, Australia, CDROM ISBN-13: 978 1 86499 940 2

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

Mound LA & Marullo R (1996). The thrips of Central and South America: An introduction (Insecta: Thysanoptera). Memoirs on Entomology, International, Vol. 6. Associated Publishers, Gainsville, 487 pp

Mound LA & Palmer JM (1974).Notes on Thysanoptera from Israel. Entomologist's Monthly Magazine. 109: 102-106

Nickle DA (2003). A checklist of commonly intercepted thrips (Thysanoptera) from Europe, the Mediterranean, and Africa at U.S. ports-of-entry (1983-1999). Part I. Key to genera. Proceedings of the Entomological Society of Washington. 105 (1): 80-99

Nickle DA (2009). Commonly intercepted thrips at U.S. ports-of-entry from Africa, Europe, and the Mediterranean. IV. Miscellaneous thripine genera excluding Frankliniella, Iridothrips, and Thrips (Thysanoptera: Thripidae). Proceedings of the Entomological Society of Washington. 111 (1): 215-238

Sharga US (1933). Biology and life history of Limothrips cerealium Haliday and Aptinothrips rufus Gmelin feeding on Gramineae. Annals of Applied Biology. 20: 308-326

Teulon DAJ & Penman DR (1992). Colour preferences of New Zealand thrips (Terebrantia: Thysanoptera). New Zealand Entomologist, 15: 8-13

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

zur Strassen R (1968). Ãkologische und zoogeographische Studien über die Fransenflügler-Fauna (Ins., Thysanoptera) des südlichen Marokko. Abhandlungen der Senkenbergischen Naturforschenden Gesellschaft. 515: 1-125

zur Strassen R (1969). Neue Angaben zur Thysanopteren-Fauna (Insecta, Thysanoptera) der Kanarischen Inseln. Commentationes Biologicae. 31 (5): 1-74

zur Strassen R (1972). Über Limothrips cerealium, die "Gewitterfliege". Natur und Museum. 102 (9): 336-342

zur Strassen R (2003). Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. Die Tierwelt Deutschlands und der angrenzenden Meeresteile nach ihren Merkmalen und nach ihrer Lebensweise, 74. Teil. Goecke & Evers, Keltern, Germany, 277 pp

zur Strassen R (2006). Checklist of the Thysanoptera (Insecta) of southern Africa. African Entomology. 14 (1): 63-68