Hoplothrips semicaecus (Uzel)

Mound, Laurence A., Wang, Jun & Tree, Desley J., 2020, The genus Hoplothrips in Australia (Thysanoptera, Phlaeothripinae), with eleven new species, Zootaxa 4718 (3), pp. 301-323 : 316

Hoplothrips semicaecus (Uzel)

( Figs 20 , 42, 43, 44 )

Trichothrips semicaeca Uzel, 1895: 249 .

Macropterous female. Body, femora and antennae light brown, tibiae and tarsi yellow, and antennal segment III partly yellow; fore wings pale. Head with maxillary stylets retracted to postocular setae, less than one fifth of head width apart medially; postocular setae bluntly pointed ( Fig. 20 ). Antennal segment III apex variable in shape with 2 (or 3) sense cones, IV with 2 (or 3–4) sense cones; ventrally IV–VI with variable number of small sensory hairs (up to 25 on IV); VIII only weakly narrowed to base ( Fig. 42 ). Pronotum without sculpture medially; with 4 pairs of pointed major setae, am small; prosternal basantra absent. Fore tarsal tooth small. Metanotum without sculpture medially. Fore wing with 8–10 duplicated cilia. Abdominal tergites II–VII with two pairs of curved wing-retaining setae; tergite IX setae S1 pointed, more than half as long as tube.

Female aptera. Largely yellow with tube brown, tergites shaded medially; antennal segment IV with fewer sensory hairs ventrally ( Fig. 43 ); compound eyes small, postocular setae long and finely pointed; maxillary stylets close together medially; fore tarsal tooth large; tergal wing-retaining setae small and straight. Male aptera. Eyes small, no ocelli; large males with fore femora swollen and tarsal tooth large; tergite IX setae S2 about half as long as S1; sternites IV–VII with specialised reticulate areas laterally, VIII with irregular transverse pore plate not extending the full width of sternite.

Specimens studied. Australian Capital Territory, Mt Majura , 1 male aptera from leaf litter, 9.i.1968 . Tasmania, Picton Valley , 1 female macroptera from dead wood, 29.v.2001 .

Comments. Described from Europe where it is widespread ( Mound et al. 2018), and with one synonym from North America, this species is also recorded from Japan and New Zealand. However, the range of variation recorded amongst specimens from New Zealand ( Mound & Walker 1986) suggests that this species originated in the southern hemisphere, with subsequent dispersal to Europe and America by human trading. Prior to the description above of bellingeni , the antennae of semicaecus were considered unique amongst Hoplothrips species worldwide in bearing ventrally on antennal segment IV a group of small sensory hairs ( Fig. 42 ) (sensilla basiconica). The similarity in the antennae of these two species might support the suggestion that semicaecus is part of the Australasian diversification within Hoplothrips , however bellingeni and semicaecus do not seem to be particularly closely related, judging from the differences in their maxillary stylets.

Figures

FIGURES 10–20. Hoplothrips species—head and pronotum. (10) lowdeni male; (11) lowdeni female; (12) nelsoni male; (13) nelsoni female; (14) oakeyi female; (15) oakeyi male; (16) reedi male; (17) reedi pronotum; (18) melanurus pronotum; (19) tarsus; (20) semicaecus female macroptera.

FIGURES 31–45. Hoplothrips species antennae. (31) bellingeni; (32) corticis (III–V); (33) giganteus; (34) lihongae; (35) lowdeni; (36) nelsoni; (37) oakeyi; (38) wrightae; (39) orientalis (III–V); (40) poultoni; (41) reedi; (42) semicaecus female macroptera; (43) semicaecus female microptera; (44) semicaecus male microptera; (45) woodsi.