The orientation of males of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) to pheromone-baited decoy ‘females’ in the field

Abstract

Field studies in Zimbabwe of the orientation of males of Glossina morsitans morsitans Westwood to decoy ‘females’ (9 × 3-mm rectangles of 2-mm thick brushed nylon, baited with sex pheromone, 15,19,23-trimethyl-heptatriacontane, and placed on a vertical, 1-m2 black cloth screen) demonstrated that (1) no olfactory response to air-borne pheromone was involved in the orientation of males to decoys, (2) the presence of decoys on a stationary screen did not increase the numbers of males landing on the screen, but they directed landings onto the decoys or the adjacent screen surface, (3) males did not differentiate between black or brown decoys, (4) males were more attracted to vertically oriented decoys on the screen surface than to decoys held away from the surface, and (5) males were more attracted to decoys at the centre of the screen than to decoys near the top or bottom edges. Points 1, 2 and 4 also applied in the case of G. pallidipes Austen using decoys dosed with its pheromone (13,23-dimethylpentatriacontane), but this species preferred black to brown decoys and showed less overt sexual activity than G. m. morsitans. Males of G. m. morsitans each removed 1–2μg of pheromone by contact with a decoy, leading to a gradual loss of the decoy's stimulatory power.

Characterization of the sexual responses of male tsetse flies, Glossina morsitans morsitans, to pheromone‐baited decoy ‘females' in the field

“…However, the sterilizing dose received, and therefore the effectiveness of the technique, is directly proportional to the duration of male-decoy contact. The present paper reports studies undertaken in the field to characterize and quantify the postlanding responses of male G.m.morsitans to such pheromone-baited decoys, complementing earlier studies on the pre-landing responses (Hall, 1987), with a view to improving prospects for the autosterilization technique.…”

“…All experiments were conducted between February 1983 and March 1985 at the Rekomitjie (Rukomechi) Research Station in the Zambezi Valley of Zimbabwe (Hall, 1987). G.rn.morsitans and the more abundant G.pallidipes were present, but only the former was studied.…”

“…All decoys were 9 x 3 mm rectangles of 2 mm thick, brushed-nylon material cleaned before use in ten changes of boiling chloroform. They were attached with their long axis vertical ('verticaldecoys';Hall, 1987) to a vertical cloth screen placed at 90" to the prevailing wind, with the side bearing the decoys facing an observation pit (Hall, 1987). Black decoys were used on a black screen since this is a most attractive colour combination (Langley et al, 1982b).…”

“…'Pendant-decoys' (Hall, 1987) were normal decoys attached to the lower end of a 5 cm length of 0.2 mm diameter wire hanging from a 2 mm diameter wire bar; the bar, and therefore the decoys. being held 5 cm away from a black 1~0 .…”

Odour-baited targets to control New World screwworm, Cochliomyia hominivorax (Diptera: Calliphoridae): a preliminary study

“…This aggregation response resembled the aggregation of muscids around stationary Glossina spp. On similar cloth targets (Hall, 1987) and may represent a behavioural response of C. hominivorax to alight on hosts near to other flies which have located a suitable site for feeding or oviposition. Aggregations were not noted on the electric nets even though some individuals did become stuck on the wires, implying that the response only occurred to flies on a solid surface.…”