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Biomedical subjects

W J Bell

Publications and source records attributed to W J Bell.

17 recordsLinked to original sources

Chemo-anemotaxis: a behavioral response to sex pheromone in nonflying insects.

The cockroach, Periplaneta americana, running on a Y-ring globe, moves downwind if an air current is directed toward the head. However, if the air current carries sex pheromone, then upwind movement is elicited. This orientation behavior is apparently a mechanism to facilitate the orientation of males searching for pheromone-secreting females.

Animals

Individual odor differences and their social functions in insects.

The evolution of individual or subgroup differences in odors of halictine bees is suggested from possible widespread intraspecific variation in pheromones. An important result of such variation may be maintenance of genetic polymorphisms; in nesting Hymenoptera odor differences may also facilitate individual nest recognition. In Lasioglosum zephyrum males habituate to odors of different females and perhaps thus save time by not trying to copulate with nonreceptive individuals. Guards (females) at nest entrances distinguish their few nestmates (other females) from other conspecific individuals by odors, seemingly pheromones. Duration of the habituation in L. zephyrum is at least an hour (perhaps much more) for males in relation to females and 6 or 7 days for guards in relation to nestmates. Studies of pheromones should take into consideration the possibility of pheromonal polymorphism in any species and the likelihood that it may be significant from biological and practical viewpoints.

Animals

Agonistic behavior in the German cockroach, Blattella germanica.

Agonistic behavior in Blattella germanica is delineated with an emphasis on fighting techniques and population factors affecting aggressiveness. Male-male, male-female, and male-male encounters are not significantly different in either level of aggressiveness or frequency. Female-female carrying oothecae are, however, more aggressive than other female-female. The mean intensity of aggression increases as population density is increased, but number of contacts per individual per unit time remains constant. Defense of specific, territories does not occur and aggressive interactions are most common during the dark portion of the photocycle, when many of the cockroaches are observed to be foraging.

Aggression