Flower Bats (Glossophaga soricina) and Fruit Bats (Carollia perspicillata) Rely on Spatial Cues over Shapes and Scents When Relocating Food

Natural selection can shape specific cognitive abilities and the extent to which a given species relies on various cues when learning associations between stimuli and rewards. Because the flower bat Glossophaga soricina feeds primarily on nectar, and the locations of nectar-producing flowers remain constant, G. soricina might be predisposed to learn to associate food with locations. Indeed, G. soricina has been observed to rely far more heavily on spatial cues than on shape cues when relocating food, and to learn poorly when shape alone provides a reliable cue to the presence of food.Here we determined whether G. soricina would learn to use scent cues as indicators of the presence of food when such cues were also available. Nectar-producing plants fed upon by G. soricina often produce distinct, intense odors. We therefore expected G. soricina to relocate food sources using scent cues, particularly the flower-produced compound, dimethyl disulfide, which is attractive even to G. soricina with no previous experience of it. We also compared the learning of associations between cues and food sources by G. soricina with that of a related fruit-eating bat, Carollia perspicillata. We found that (1) G. soricina did not learn to associate scent cues, including dimethyl disulfide, with feeding sites when the previously rewarded spatial cues were also available, and (2) both the fruit-eating C. perspicillata and the flower-feeding G. soricina were significantly more reliant on spatial cues than associated sensory cues for relocating food.These findings, taken together with past results, provide evidence of a powerful, experience-independent predilection of both species to rely on spatial cues when attempting to relocate food

Norway Rats\u27 Communication About Foods and Feeding Sites

After interacting with a recently fed demonstrator rat (Rattus norvegicus), a naive observer rat exhibits substantial enhancement of its preference for whatever food its demonstrator ate. Such social effects on food preference in rats are surprisingly robust and able to reverse both congenital flavor preferences and poison-induced, learned flavor aversions. Analysis of the pheromonal signals emitted by demonstrator rats that alter the food preferences of their observers indicates that experience of CS2 (a substance present in rat breath) together with the odor of a food is sufficient to enhance an observer rat\u27s subsequent preference for the food. Adding CS2 to a food substantially increases intake of that food by both rats and mice (Mus domesticus), suggesting that CS2 could be used to enhance intake of poison baits by rodent pests. Recent analyses of the use by rats of odor trails indicate that additional pheromones attractive to rats remain to be described

Social influences on the mate choices of male and female Japanese quail

For the last decade, Japanese quail (Coturnix japonica) have served as subjects in an extended series of studies of social influences on reproductive behavior. The results of those studies are summarized here. Females prefer to affiliate with males that they have seen courting and mating, whereas males avoid females that they have seen courting and mating, and both males and females prefer to copulate with the same individuals with whom they prefer to affiliate. Further, females lay more fertilized eggs after mating with a male they have seen mate with another female than after mating with a male they did not watch while he mated. Female quail’s preferences among males are also affected by observation of males ’ aggressive interactions, with virgin females preferring dominant males and sexually experienced females preferring subordinates. Evidence is provided suggesting that: (1) responses of quail to observation of a member of the opposite sex mating is an adaptive specialization of information processing systems involved in quail social learning and (2) mate-choice copying in quail can influence the evolution of male secondary sexual characteristics