Monilothrips kempi Moulton, 1929

Panchaetothripinae, Thripidae, Terebrantia, Thysanoptera

Figures

Fig. 1: 8-segmented antenna, segments III and IV with forked sense cone, terminal segments V-VIII
Fig. 2: Head dorsal with ocellar triangle
Fig. 3: Pronotum
Fig. 4: Meso- and metanotum
Fig. 5: Meso- and metasternum
Fig. 6: Fore wing and fore wing distal region
Fig. 7: Sternite VII and basal sclerites of ovipositor
Fig. 8: Segments 8-10 ventral with ovipositor
Fig. 9: Tergites VII and VIII
Fig. 10: Tergites VIII-XI

Monilothrips kempi damages various ferns. Both sexes fully winged. Body dark brown; legs brown with base and apex of tibiae yellow, also tarsi; antennal segments I & III brownish yellow, II pale, IV & V yellow at base, VI-VIII dark brown; fore wings light brown with a pale patch subbasally and interveinal surface pale. Antennae 8-segmented; segments III & IV with forked sense cone, VIII twice as long as VII (Fig. 1). Head with a broad reticulated posterior collar (3 rows of reticles), long ocellar setae of equal length, and 3 pairs of prominent postocular setae (Fig. 2). Pronotum relatively smooth, with stout transverse carina parallel to posterior margin, 1 pair of long posteroangular and 1 pair of long anteroangular setae (Fig. 3). Mesonotum reticulate, not divided longitudinally. Metanotum reticulate medially; median setae near posterior margin; without median triangle of sculpture (Fig. 4 and 5). Mid and hind tarsi 2-segmented. Fore wing first vein close or fused to costal vein; veins with two complete rows of long setae; anterior margin with setae and cilia but setae longer than cilia and up to twice as long as wing width; posteromarginal cilia undulated (Fig. 6). Tergites II-VIII polygonally reticulate behind the thin antecostal line, median setae small, posterior margins with broad craspedum (Fig. 9); IX & X nearly smooth (Fig. 10); X with complete longitudinal split. Sternites each with 3 pairs of long setae close to posterior margin; sternite II & III with complete craspedum at posterior margin, also laterally on IV-VII.
Male smaller than female; with 2 pairs of thorn-like setae on tergite IX; without sternal glandular areas.

The genus Monilothrips Moulton, 1929
Only one species is placed in the genus Monilothrips which is widespread in India, California and southern Africa. Monilothrips kempi has 8-segmented antennae with forked sense cone on segments III and IV, a single long seta at each angle of pronotum, 2 complete rows of setae on the fore wing, fore wing anterior margin with setae longer than costal cilia, and a broad craspedum on posterior margin of tergites II-VIII. Compared to mostly other Panchaetothripinae surface of head, pronotum and fore legs is not strongly reticulated except the occiptal collar on head.

Monilothrips kempi is a distinct species and differs from most other Panchaetothripinae due to the surface of head, pronotum and fore legs which is not strongly reticulated except the occiptal collar on head, and the presence of 2 pairs of elongated pronotal setae. It is similar to the species of Hercinothrips in having 2-segmented tarsi and two complete rows of setae on the fore wing. But in Hercinothrips head and pronotum have reticulate sculpture, head constricted posteriorly, without a distinct occipital ridge, and without elongated pronotal setae. Furthermore, the species is similar to Panchaetothrips noxius in having 2-segmented tarsi, a distinct occipital ridge, and in lacking a posteromarginal comb of microtrichia on tergite VIII. But unlike Monilothrips kempi, in Panchaetothrips noxius the head shows a reticulate sculpture and is constricted posteriorly, without elongated pronotal setae, the metanotum has a weakly defined sculptured triangle medially, first vein setal row incomplete and second vein without setae, tergites with conspicuously dark, stout and long setae, tergite X elongate and tubular. Xestothrips glabratus has no strong reticulate sculpture neither on head nor on pronotum. Compared to Monilothrips kempi, this species has a posteriorly constricted head, pronotum without long setae, fore wings uniformly dark brown and with first vein setal row incomplete, 1-segmented tarsi, and tergite VIII with a complete posteromarginal comb of microtrichia. Compared to other Panchaetothripinae with a distinct occipital ridge, only in Monilothrips kempi the occipital collar shows in contrast to the other part of the head a heavy reticulate sculpture. In Xestothrips glabratus collar and rest of the head are similar sculptured. In Helionothrips errans and Panchaetothrips noxius the collar is weakly sculptured to the rest of the head. Like Monilothrips kempi, Panchaetothrips noxius and Selenothrips rubrocinctus have fore wing costal setae up to twice as long as wing width medially. In contrast, Selenothrips rubrocinctus has uniformly dark brown fore wings, 1 segmented tarsi, a complete posteromarginal comb on tergite VIII and a pronotum with transverse striate sculpture.

Life history
As with other thrips species the life cycle from egg to adult is dependent on temperature. The full cycle can take about 15 days to over a month and adults may live for more than one month producing several generations in one year depending on seasonal weather (Lewis 1973). With greenhouse temperatures the developmental time from egg to adult can decrease to about one week.

Host plants
Recorded from various ferns, including Blechnum australe, Adiantum aethiopicum, Polystichum sp., Hypolepis sparsisora.

Vector capacity
None identified, but possible mechanical distribution of phytopathogenic fungi and bacteria.

Damage and symptoms
-

Detection and control strategies
-

Additional notes
Larvae and adults feed on fern fronds.

Biogeography

India, USA. (California), southern Africa. Lesotho (Mamathes), South Africa (Limpopo: Mariepskop).

Hood JD (1959). A note on Monilothrips kempi Moulton (Thysanoptera: Thripidae). Journal of the Entomological Society of Southern Africa. 22 (2): 489-493

Jacot-Guillarmod CF (1942). Studies on South African Thysanoptera - III. Journal of the Entomological Society of Southern Africa. 5: 64-74

Kudo I (1992). Panchaetothripinae in Japan (Thysanoptera, Thripidae), 3. Monilothripini and Tryphactothripini. Japanese Journal of Entomology. 60 (3): 467-482

Lewis T (1973). Thrips: their biology, ecology and economic importance. Academic Press Inc., London Ltd., 349 pp

Moulton D (1929). Thysanoptera from India. Records of the Indian Museum. 31 (2): 93-100

Wilson TH (1975). A monograph of the subfamily Panchaetothripinae (Thysanoptera: Thripidae). Memoirs of the American Entomological Institute. 23: 1-354

zur Strassen R (1960). Catalogue of the known species of South African Thysanoptera. Journal of the Entomological Society of Southern Africa. 23 (2): 321-367