Family: HETEROTHRIPIDAE

 

This family comprises 70 species in four genera, all from the Americas (Mound & Marullo, 1996). They have 9-segmented antennae, with distinctive sensoria that comprise a continuous porous band around the apex of segments III and IV. Little is known of their biology, but they are probably all flower-feeders, and some species are host specific. Sometimes they are locally common, but none is known to damage any crop.


Heterothrips arisaemae Hood

Available names: Original name Heterothrips arisaemae Hood, 1908.


Biology: So far as is known, this species breeds only in the flowers of the pitcher plant, Arisaema triphyllum, commonly known as Jack-in-the-Pulpit.


Distribution: Eastern North America.


Recognition: Body brown, tarsi and apices of tibiae yellow; antennae brown, segment III yellow; forewing brown with sub-basal white band. Antennal segment III elongate conical, basal stem divided into 3 sections, apical sensorium continuous around segment with irregular double row of pores. head with setae small, one pair arising within ocellar triangle. Pronotal setae all short, surface with little sculpture. Metanotum with transverse lines of sculpture on anterior half but concentric lines on posterior half, all bearing microtrichia. Tergites II to VIII with median pair of setae long and close together medially; lateral thirds of tergites with many discal microtrichia and posterior margins with long microtrichia arising from small plates; tergites VI, VII and VIII with posteromarginal comb complete medially. Sternites with numerous discal microtrichia and 4 pairs of marginal setae.
Male micropterous with very small wing lobe; sternites III to VIII with broadly oval glandular area medially.


Related species: More than 60 species are known in this genus. Mound & Marullo (1996) provided a key to these, but identification of many is difficult because of the lack of studies on intraspecific variation.


Generic relationships: Four genera are currently recognised in the Heterothripidae, all from the New World, but most of the species are placed in the genus Heterothrips. Species in these genera have 9-segmented antennae that, unlike the species of Melanthripidae, have the sensoria on segments III and IV continuous around the apex of these segments. The wings are slender as in species of Thripidae.

         

Heterothrips arisaemae

 

Antennal segments III-IX