The role of multiple cues in mate choice has been much discussed. In many animals, signals of different modalities, such as acoustic, visual, chemical or mechanical, are given simultaneously and accompanied by sophisticated behavior during courtship.

When males produce a variety of signal types, it is often not clear whether all of these signals are important in female mate choice. Courtship signals sometimes reach of an extreme complexity and these signals seem to provide even redundant information about their signaler.

One should distinguish long range and close range communication signals. Long distance, or calling, signals are primarily used to attract conspecific mates (mates of own species) at a distance. The calling signal has to provide reliable species-specific identification and ease of localization. It is suggested that the long range mating signals are likely to be subject of a stabilizing selection.

Another situation appears in the course of close range communication. Courtship songs produced by a male in a close proximity of a female allows her not only to recognize conspecific mate, but also evaluate the mate “quality”. In long range systems, which are relatively stable, it is much easier to extract information about the species of a signaler than about the quality of a signaler. In close range systems, some courtship parameters can be more stable and may be used for species recognition, whereas other, more variable, parameters may serve for the evaluation of mate quality. It is suggested that courtship signals are to a great extent driven by sexual selection and therefore, could evolve faster than the long range signals. We will discuss possible mechanisms underlying evolution of mate preferences for multiple courtship traits.

Space visual perception keeps being actively investigated even after decades of research. Including the function level we are far from full understanding of many fundamental questions of perception, key ones being, firstly, the detection of function connections between physical and visually perceived space and, secondly, the investigation of those physical parameters of the environment that are crucial for structure definition and visual space construction. The transition of a flat 2D retinal image to a 3D one is determined by sophisticated types of human visual system activity. These are investigated by differently specialized biologists joined by engineers and mathematicians who develop technical vision systems. Painters also should be added to this list, because space visual perception has always been topical for art, so important theoretical and practical experience has been accumulated in this sphere. Really, an artist painting, for example, a landscape or a portrait faces a paradoxical task to transmit the tridimensional world on a flat surface (paper, a canvas or a board) (Raushenbach, 2002). ancient wall painting, medieval, renaissance pictures or modern art are different examples of solving this space visual task. In different historical periods and cultures painters worked out their own way of the transmission of space depth and volume on a surface including geometrical ways (direct perspective, inverted perspective axonometric). The fact that in spite of all the conventionality of the art an observer looking at a picture almost always has a strong illusion of depth proves that artists intuitively have worked out some ways of the transmission of space depth and volume that don’t contradict natural visual perception mechanisms. Different ways of the transmission of space depth and volume in painting will be analyzed in the presentation in the context of visual perception mechanisms.