Generalization of convex shapes by bees: what are shapes made of?

For about 70 years, bees were assumed not to possess the capacity to discriminate among convex shapes, such as a disc, a square or a triangle, based on results of early studies conducted by presenting shapes on horizontal planes. Using shapes presented on a vertical plane, we recently demonstrated that bees do discriminate among a variety of convex shapes. Several findings, summarized here, provide indirect evidence that discrimination is based on a cue located at the shapes' boundaries.

Importance of learning in the response of ewes to male odor.

Exposure of anestrous ewes to a ram or its odor results in the activation of the luteinizing hormone (LH) secretion leading to reinstatement of cyclicity in most females. Sexual experience and learning have been suggested as important factors to explain the variability of the female responses. In experiment 1, we compared the behavioral and endocrine responses of four groups of anestrous females that differed in age (young or adult) and previous exposure to males [naive (no exposure) or experienced (courtship behavior for young and numerous mating for adults)].

Shape discrimination by wasps (Paravespula germanica) at the food source: generalization among various types of contrast.

Wasps ( Paravespula germanica) were trained and tested at an artificial feeding site, using convex shapes that produced colour contrast, luminance contrast, or motion contrast against the background. With each of the three types of contrast, we tested the wasps' capacity to discriminate the learned shape from novel shapes. In addition, in each experiment we tested the wasps' capability to recognize the learned shape when it offered a different type of contrast than that it had during the training.

Discrimination of closed shapes by two species of bee, Apis mellifera and Megachile rotundata.

In the present study, the performance of two bee species, the honeybee Apis mellifera and the leaf-cutter bee Megachile rotundata, in discriminating among various closed (convex) shapes was examined systematically for the first time. Bees were trained to each of five different shapes, a disc, a square, a diamond and two different triangles, all of the same area, using fresh bees in each experiment. In subsequent tests, the trained bees were given a choice between the learned shape and each of the other four shapes.

Visual localization within single geometric planes of a space habitat.

Background: The present study investigated how human subjects capture and restore visual information within a line representation drawing the three-dimensional configuration of a space module.

Methods: Nine subjects were asked to perform a visual localization task within this geometric model. The task consisted of localizing a light point appearing during 3 s in 40 different spatial positions and for 8 tilt angles of the model in the following random order: 0 degree, 45 degrees, 180 degrees, 225 degrees, 90 degrees, 315 degrees, 135 degrees, and 270 degrees.