Heterothripidae

Biology

Of the 66 species currently listed in this family, all but one are considered to be phytophagous, feeding and breeding in flowers, presumably exhibiting a high level of host specificity (Mound & Marullo, 1996), and pupating in a silken cocoon at soil level. The exception is Aulacothrips dictyotus that is known to breed on, as well as pupate on, the tergites of the homopteran, Aethalion reticulatum, and it presumably feeds as an ectoparasite on this bug (Izzo et al., 2002).

Recognition

Species of Heterothripidae all have nine antennal segments, the distal segments being more or less distinct from each other, and the sensoria on segments III and IV are continuous around the apex. Lenkothrips species have these sensoria curving basally on the segments, and in Aulacothrips the sensoria are convoluted over the entire surfaces of these two segments.

In the head the tentorial bridge is not developed, and sternite VII in females lacks the pair of supernumerary setae retained in Aeolothripidae that are considered to be derived from the ancestral sternite VIII. The metanotal median setae are close to the posterior margin, but the forewings are slender with two almost continuous rows of veinal setae. Prominent setae are developed only in Aulacothrips, but most species have conspicuous microtrichial combs on the posterior margins of the tergites.

Genus and species diversity

Four genera are recognised in this family, Heterothrips with 60 species, Scutothrips with four species, Lenkothrips with two species, and Aulacothrips with one species, see Mound's Thysanoptera pages.

Geographic distribution

Members of this family are known only from the Americas, and a key to these species is provided by Mound & Marullo (1996). Species of Heterothrips have been described between New York and Illinois in the North and Argentina in the South, whereas the species of the other three genera are known only from the Neotropics.

Systematics and classification

The Heterothripidae is one of eight families recognised in the Thysanoptera suborder Terebrantia.

Species in this family are unusual in having the sensoria on the third and fourth antennal segments forming a continuous band. In most species this sensorium is only around the segment apex, but in Lenkothrips it extends as a loop to the midpoint of both segments, and in Aulacothrips it is looped and highly convoluted (Mound et al., 1980).

Bhatti (2006) proposed that the family Heterothripidae should be considered as a superfamily, Heterothripoidea, and he placed Aulacothrips in a new family Aulacothripidae. The unusual structure of A. dictyotus is presumably related to its remarkable biology, and there is no reason to consider it as representing a distinct family, and thus the sister taxon of the other Heterothripidae (Mound & Morris 2007).

Families A-Z