Learning and discrimination of coloured papers in the walking blowfly, Lucilia cuprina

Abstract

A new training and testing paradigm for walking sheep blowflies, Lucilia cuprina, is described. A fly is trained by presenting it with a droplet of sugar solution on a patch of coloured paper. After having consumed the sugar droplet, the fly starts a systematic search. While searching, it is confronted with an array of colour marks consisting of four colours displayed on the test cardboard (Fig. 1). Colours used for training and test include blue, green, yellow, orange, red, white and black. Before training, naive flies are tested for their spontaneous colour preferences on the test array. Yellow is visited most frequently, green least frequently (Table 2). Spontaneous colour preferences do not simply depend on subjective brightness (Table 1). The flies trained to one of the colours prefer this colour significantly (Figs. 5 and 9-11). This behaviour reflects true learning rather than sensitisation (Figs. 6-7). The blue and yellow marks are learned easily and discriminated well (Figs. 5, 9, 11). White is also discriminated well, although the response frequencies are lower than to blue and yellow (Fig. 11). Green is discriminated from blue but weakly from yellow and orange (Figs. 5, 9, 10). Red is a stimulus as weak as black (Figs. 8, 9). These features of colour discrimination reflect the spectral loci of colours in the colour triangle (Fig. 14). The coloured papers seem to be discriminated mainly by the hue of colours, but brightness may also be used to discriminate colour stimuli (Fig.13).

Colour in the eyes of insects

“…Further physiological data are necessary to put these conjectures to the test. We may note that the central photoreceptors of flies mediate colour vision in blowflies (Fukushi 1989;Troje 1993). A specific colourful role has also been inferred for the central photoreceptors of dolichopodids, which have two types of spectrally conjugated corneal reflectors organized in extremely regular, interlaced patterns (Bernard 1971).…”

“…Convincing evidence for colour vision in other insects has been obtained only recently. The photoreceptor cells mediating colour vision in the blowfly Lucilia, the central photoreceptors R7 and R8 (Fukushi 1989;Troje 1993), exist in two pairs with different visual pigments. The two pairs are randomly distributed in the retina, i.e.…”

Calliphorid fly (Diptera, Calliphoridae) attraction to different colored traps in the Tingua Biological Reserve, Rio de Janeiro, Brazil

“…HALL (1995) also observed the preferential attraction of L. cuprina to the color yellow, and observed similar behavior by phytophagous species that are preferably attracted to this color. On the other hand, FUKUSHI (1989) observed that the more attractive trap colors for this species were blue and yellow, with red and black being the least attractive colors. WALL & SMITH (1996) studied the color discrimination by the sheep blowfly Lucilia sericata (Meigen, 1826).…”

Different parameters support generalization and discrimination learning in Drosophila at the flight simulator

“…It is generally agreed that R7 and R8 receptors feed into color-coding mechanisms; however, the exact contribution of the two subtypes of R7 and R8 receptors belonging to two ommatidial types is still unknown. Experiments by Troje (1993) and Fukushi (1985Fukushi ( , 1989 with Lucilia indicate that both subtypes may be involved. Since in our experiments the UV range was not used, the R8 receptors were the most strongly excited ones (Fig.…”