HORNET BUILDING ORIENTATION IN ADDITIONAL MAGNETIC FIELDS

Abstract

In artificial breeding boxes (ABBs), as in nature, hornet (Vespa oriental is) workers build combs oriented downwards connected by pedicles to the roof. The cells in such combs face downwards with a scatter angle of 3−14° from the vertical. This vertical direction seems to be the result of the combined influence of both the gravitational force and the vertical component of the earth's magnetic field intensity vector. Hornet workers placed in ABBs in additional static magnetic fields, compensated the vertical component of the earth's magnetic field vector, built small combs or singl cells on the side walls, or on the floor. They initiated the cells in the horizontal direction. In the boxes where the compensating field was uniform the cells' axes were directed horizontally, whereas in the boxes placed in a non-uniform compensating field, the cells were gradually oriented downwards. In very nonuniform horizontal additive fields with intensities of the same order of magnitude as that of the earth's field, hornets were disoriented. They built combs and single cells directing them towards the regions where the magnetic field was weakest, and even upwards.