Visual and olfactory cue interaction in resource-location by the blowfly, Lucilia sericata

The interactions between olfactory and visual cues in the landing responses of the blowfly Lucilia sericata (Meigen) (Diptera: Calliphoridae) were exa mined in a laboratory wind tunnel. The odour of liver and sodium sulphide s olution released at 1 L/min, resulted in a greater number of landings, clos er to, but downwind of, the central odour release point, than when odour wa s absent. Three-day-old protein-deprived females landed in greater numbers than protein-fed female flies of the same age; no difference existed betwee n 6-day-old protein-fed or protein-deprived females. Six-day-old, protein-f ed flies landed closer to the odour source than did 3-day-old, protein-fed flies. In the presence of odour, flies landed closer to the central release point when it was accompanied by a visual cue. No such effect of the visua l cue was evident in the absence of odour. When a plain white sticky-surfac e (25 x 25 cm) was paired with an identical white surface plus odour, appro ximately equal numbers of flies landed when the surfaces were placed togeth er; increasingly higher numbers of flies landed on the surface with the odo ur cue when the distance between the surfaces was increased, When a white s urface with a visual cue was presented with the plain white surface plus od our, more flies landed on the white surface with the visual cue than on the plain white surface with odour when they were close together. However, as these two surfaces were moved apart, flies landed increasingly more on the surface with the odour than the surface with the visual cue. The results sh ow that while odour cues may enhance the induction of landing by female L. sericata, visual cues are important when selecting a final landing site.