Spectral Sensitivity of the Compound Eye of Coccinella septempunctata (Coleoptera: Coccinellidae)

Abstract

The spectral sensitivity of the compound eyes of three age groups of both sexes of Coccinella septumpunctata L. was measured electrophysiologically at wavelengths of 350-700 nm. Both sexes in each group show two peaks of sensitivity, one at 365 nm and a second at 500 nm. Female beetles were slightly more sensitive than male beetles, but the difference was not significant. Beetles 29-33 d old were significantly more sensitive than younger (16-24 d) or older (38-42 d) beetles. KEY WORDS Insecta, Coccinella septempunctata, spectral sensitivity, vision Coccinella septempunctata (L.) is a European predator on several species of aphids and is now established in the eastern and central parts of North America (Schaeffer et al. 1987). This study on the beetles visual sensitivity was done to determine what colors they could detect that may be important in mating, food selection, and host plant detection.

The role of vision and color in the close proximity foraging behavior of four coccinellid species

“…These results imply that C. septempunctata uses color contrast to increase its foraging eciency. C. septempunctata has photoreceptors in the UV, blue, and green, suggesting that this coccinellid is sensitive to green stimuli and that it has the ability to distinguish between red and green colors (Agee et al 1990;Lin and Wu 1992;Lin 1993). A consequence of these color cues is that the green morphs of the pea aphids could have a distinct advantage over the red morphs since the primary background, the host plant, of the pea aphids is green.…”

Food Relationships

“…The spectral sensitivity and structure of the compound eyes of C. septempunctata adults have been studied (Agee et al 1990 ) and photoreceptors for three electromagnetic wavelength ranges have been documented: UV, green and a third between UV and green. Storch (1976) found visual perception to be of little importance to fourth instar C. transversoguttata ; however, the prolegs were important in the detection of prey as they bear sensillae which detect prey at a distance.…”

Unconditioned and conditioned responses to colour in the predatory coccinellid, Harmonia axyridis (Coleoptera: Coccinellidae)

“…These pillars both reflected a signifi cant amount of light, as measured by a Cary 14 reflectance spectrophotometer, in the range of hues visible to ladybird bee tles, 310-600 nm ( Fig. 1) (Agee et al, 1990;Lin, 1993). …”

“…Ladybirds have three types of visual receptors: UV, blue, and green receptors that allow them to respond to wavelengths from 310-600 nm (Agee et al, 1990;Lin, 1993). Some ladybird species preferentially attack aphids that contrast with their background (Harmon et al, 1998), indicating colour perception.…”