Baliothrips kroliBaliothrips kroliBoth sexes fully winged. Body and femora dark brown, tibiae light brown with apices paler, tarsi yellow; antennae brown with segment III yellow, IV light brown; fore wings shaded, scarcely paler medially but pale at base. Antennae 7-segmented; segments III–IV with short forked sense cone; III almost 3 times as long as wide, VII short. Head longer than wide, projecting in front of eyes, with two pairs of ocellar setae; pair III small, arising on anterior margins of ocellar triangle near the first ocellus, pair II longer than III; postocular setae pair II displaced posterior to this row of setae; maxillary palps 3-segmented. Pronotum with 2 pairs of long posteroangular setae, with no discal setae. Metanotum with irregular longitudinal striations, median setae arising well behind anterior margin; campaniform sensilla absent. Fore wing first vein with 2–4 setae on distal half; second vein with row of about 10 setae. Abdominal tergite II with 4 lateral marginal setae; tergites V–VIII with paired ctenidia laterally, on VIII posteromesad to spiracles; tergite VIII posterior margin with a few small fine teeth laterally; pleurotergites without discal setae. Sternites II–VII with three pairs of marginal setae, S1 arising in front of posterior margin; sternites without discal setae.
Male smaller and paler than female; tergite VIII posterior margin apparently without a comb; sternites III–IV with large oval pore plate.
Three species are now placed in the genus Baliothrips (Bhatti & Mound, 1980; Collins, 2010a; Zhang et al., 2018). Two of these occur in Britain, and they share the unusual character state of setal pair S1 on sternite II arising sub-marginally. Together with Stenothrips graminum, these three species possibly represent a European radiation of grass-living species from the genus Thrips, in which there is a tendency to reduce the maxillary palps to a 2-segmented condition, although this reduction is not seen in B. kroli. This contrasts with the Asian radiation of grass-living species derived from Thrips that are placed in the genera Stenchaetothrips and Fulmekiola, all of which have 3-segmented palps. B. kroli differs from dispar in that the head projects forward of the eyes, campaniform sensilla are not present on the metanotum, and in the male there are oval pore plates only on sternites III–IV.
Feeding and breeding on the leaves of various Poaceae and Cyperaceae, including Glyceria, Phragmites, Carex and Scirpus, often in damp areas.
Recorded from the southern half of England as far north as Manchester and Yorkshire (Mound et al., 1976). It is also found widely across Europe from France and Scandinavia to Romania and Russia (zur Strassen, 2003; as Euchaetothrips kroli (see Collins, 2010a)).
THRIPIDAE - THRIPINAE
Baliothrips kroli (Schille)
Thrips Kroli Schille, 1912: 7
Thrips picea Schille, 1914: 126
Euchaetothrips ingens Priesner, 1921: 119
Euchaetothrips kroli f. adusta Maltbaek, 1928: 176
Euchaetothrips kroli f. pallens Maltbaek, 1928: 176
Bhatti JS & Mound LA (1980) The genera of grass and cereal-feeding Thysanoptera related to the genus Thrips (Thysanoptera: Thripidae). Bulletin of Entomology 21: 1–22.
Collins DW (2010a) Thysanoptera of Great Britain: a revised and updated checklist. Zootaxa 2412: 21–41.
Mound LA, Morison GD, Pitkin BR & Palmer JM (1976) Thysanoptera. Handbooks for the Identification of British Insects 1 (11): 1–79.
Zhang SM, Wang ZH, Li YJ & Mound LA (2018) One new species, two generic synonyms and eight new records of Thripidae from China (Thysanoptera). Zootaxa 4418 (4): 370–378.
zur Strassen R (2003) Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. Die Tierwelt Deutschlands 74: 1–271.
