Microcephalothrips abdominalis
Recognition data
Distinguishing features
Both sexes either fully winged or with wings shorter than thorax width. Body brown, fore tibiae, tarsi and antennal segment III paler; forewings brown. Head small, wider than long, only two pairs of ocellar setae present, pair III small and anterolateral to ocellar triangle. Antennae 7-segmented; segments III � IV with small forked sensorium. Pronotum wider at posterior than anterior margin; two pairs of short posteroangular setae, five pairs of posteromarginal setae. Metanotal sculpture linear but forming lens-like shape posteriorly, campaniform sensilla present; median setae arise behind anterior margin. Forewing first vein with three setae on distal half, second vein with about three setae. Abdominal tergites with craspedum of triangular lobes on posterior margins, discal area without sculpture on posterior half; tergites V � VIII with paired ctenidia, on VIII posteromesad to spiracle; tergite VIII posteromarginal comb with slender microtrichia arising from broad bases. Sternites with double row of discal setae, without craspeda. Male smaller and paler; tergite VIII posterior margin with craspedum of triangular lobes similar to preceding segments; sternites with craspeda of triangular lobes, III � VII with small circular glandular area.
Variation
The sensoria on antennal segments III � IV are usually forked, although one half of these forks is sometimes difficult to observe. However, individuals have been studied from various localities in which the sensorium on one or both segments is simple not forked, or more rarely with just the apex developed into a short fork. Variants of this sort have been described from China as separate species, but these are listed here as synonyms.
Related and similar species
Only one species is known in the genus Microcephalothrips. It is closely related to the genus Thrips, but has a distinctive craspedum on the posterior margin of the abdominal tergites, and the head is unusually small in comparison to the pronotum.
Taxonomic data
Current valid name
Microcephalothrips abdominalis (Crawford DL)
Original name and synonyms
Thrips abdominalis Crawford DL, 1910: 157
Thrips femoralis Jones, 1912: 4
Thrips crenatus Watson, 1922: 35
Thrips microcephalus Priesner, 1923: 116
Thrips (Ctenothripiella) gillettei Moulton, 1926: 126
Thrips oklahomae Watson, 1931: 342
Microcephalothrips armatus Ananthakrishnan, 1956: 133
Aureothrips marigoldae Raizada, 1966: 278
Stylothrips brevipalpis Karny, 1927: 206
Paraphysopus burnsi Girault. 1927: 2
Microcephalothrips chinensis Feng, Nan & Guo, 1998: 257
Microcephalothrips jigongshanensis Feng, Nan & Guo, 1998: 258
Microcephalothrips yanglingensis Feng, Zhang & Sha, 2002: 167
Family placement
Thripidae, Thripinae
Common names
Sunflower thrips
Biological data
Life history
Breeding in flowers
Host plants
Various Asteraceae, sometimes abundant in crops of sunflowers (Helianthus annuus) (Asteraceae).
Tospoviruses vectored
None
Crop damage
No serious damage recorded, but large populations can cause some distortion of flowers such as Pyrethrum and Sunflowers.
Distribution data
Area of origin
Possibly Central America
Distribution
Widespread in the USA, also around the world in the tropics and subtropics.
