Many insects cannot see red, but two beetle species from the Mediterranean region are unique in their ability to perceive this color, according to an international research team.

Insect eyes are typically sensitive to ultraviolet, blue, and green light. Except for certain butterflies, most insects lack the ability to see red. However, bees and other insects are drawn to red flowers like poppies, not because of the color red itself, but due to the UV light reflected by these flowers.

Unlike other insects, two beetle species from the eastern Mediterranean, Pygopleurus chrysonotus and Pygopleurus syriacus of the Glaphyridae family, can see the color red. These beetles primarily feed on pollen and are attracted to plants with red flowers such as poppies, anemones, and buttercups.

Photoreceptors for Long-wave Light

Dr. Johannes Spaethe from the Chair of Zoology II at Julius-Maximilians-Universität (JMU) Würzburg in Germany, along with Dr. Elena Bencúrová and researchers from the Universities of Ljubljana and Groningen, conducted experiments that revealed the beetles' ability to perceive red. The study, published in the Journal of Experimental Biology, utilized electrophysiology, behavioral experiments, and color trapping to demonstrate that these beetles have four types of photoreceptors in their retinas that respond to UV, blue, green, and deep red light.

Field experiments confirmed that the beetles use true color vision to identify red targets and exhibit a clear preference for red colors. This discovery positions the Glaphyrid family as a valuable model system for studying beetle visual ecology and the evolution of flower signals and pollinator detection.

New Insights for Evolutionary Studies

The researchers suggest that flower colors have evolved to match the visual systems of pollinators over time. However, the diverse color preferences among the Eulasia, Glaphyrus, and Pygopleurus genera within the Glaphyrid family indicate a flexible physiological and behavioral basis for perceiving red and other colors.

The researchers propose that the visual systems of these beetles may adapt to flower colors more than previously thought, given the wide range of flower colors in the Mediterranean region and the varying color preferences of the beetles.

Source: Mirage News