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Due to its multifunctional and complex role in the honey bee colony functioning and health (construction material allowing food storage, brood rearing, thermoregulation, mediation in chemical and m...

SummaryAs a possible way to help control varroa mites, some beekeepers advocate the use of cells smaller than the regular size commonly used by beekeepers. This paper addresses two of their principal arguments, namely that honey bees built smaller cells under natural conditions in the past, and that a “fatal” error occurred at the turn of the 20th century when a new and allegedly misleading method of estimating cell density was introduced. Historical data show not only that cell sizes were not smaller in the past, but also that estimating cell densities was not an issue before the introduction of wax foundation. Moreover, not realizing that the two methods of estimating cell densities are equivalent, the proponents of small cells have erroneously corrected the data reported by the authors of the 17th, 18th and 19th centuries. In conclusion, the claim that cells were smaller in the past is not only not supported by the historical records, but rests on a distortion of the historical records resulting from a...

Two series of cafeteria tests involving six varieties of Trifolium repens were conducted to confirm the preference of fossorial Arvicola terrestris for acyanogenic white clover (T. repens) and to investigate their responses to repeated exposures to toxic plants. The animals were offered the choice between two bunches of freshly harvested white clover. In 261 simple choice tests, 160 individuals were tested for various combinations of three acyanogenic and three cyanogenic varieties. They showed a clear preference for the acyanogenic morphs, both in comparisons between opposite cyanotypes and in two control situations involving either self-comparisons or comparisons between similar cyanotypes. In 320 repeated choice tests, 40 voles assigned to three groups (comparisons between opposite cyanotypes and control comparisons between similar cyanotypes) were tested eight times for the same alternative. They showed a persistent preference for the acyanogenic morph and significantly reduced their total food consumption when they had a strictly cyanogenic diet. In the latter case, they stored or wasted more plant material than in the other treatments. These voles also ingested high amounts of cyanide which suggests good detoxification abilities and a possible habituation to cyanide.

We report experimental results showing that, under both laboratory conditions as well as in outdoor enclosures, the fossorial vole Arvicola terrestris preferentially feeds on acyanogenic white clover (Trifolium repens) when offered the choice between two varieties (Ladino and Aran) differing highly in their content in cyanogenic glycosides. We also observed that the voles adapted their diet and reduced their relative consumption of the cyanogenic variety during experiments conducted for two to three weeks in outdoor enclosures as compared to shorter tests conducted for 48 hr in laboratory cages. In addition, we report a similar preference for the acyanogenic Ladino variety for the slugs Arion ater and A. subfuscus.

regulatory effects was obscured by linear and nonlinear trends in one and two cases, respectively. The data support the hypothesis that time-delayed and nonlinear mechanisms of population regulation oper- ate in fossorial populations of A. terrestris. Furthermore, the data are consistent with regulatory mechanisms involving predator-prey interactions, while the causation of the unusually long cycle is still an open question. Finally, the presence of trends in these time series suggests that water vole populations track some long-term climatic changes in the environment.

The golden hamster carries food back to its nest along a direct path. In a situation combining a passive outward journey with the elimination of visual and various other exteroceptive cues, the subjects continued to return to their nest site and were not influenced by alterations of the earth's magnetic field. Experiments in which the animals started their hoarding trips from a changing point of departure, or were transferred to an unfamiliar experimental space, suggest that they orientate by path integration and that they assess the angular, but not the linear component of a passive outward journey.