Ocellar adaptations for dim light vision in a nocturnal bee.

Growing evidence indicates that insect ocelli are strongly adapted to meet the specific functional requirements in the environment in which that insect lives. We investigated how the ocelli of the nocturnal bee Megalopta genalis are adapted to life in the dim understory of a tropical rainforest. Using a combination of light microscopy and three-dimensional reconstruction, we found that the retinae contain bar-shaped rhabdoms loosely arranged in a radial pattern around multi-layered lenses, and that both lenses and retinae form complex non-spherical shapes reminiscent of those described in other ocelli.

A three-dimensional atlas of the honeybee neck.

Three-dimensional digital atlases are rapidly becoming indispensible in modern biology. We used serial sectioning combined with manual registration and segmentation of images to develop a comprehensive and detailed three-dimensional atlas of the honeybee head-neck system. This interactive atlas includes skeletal structures of the head and prothorax, the neck musculature, and the nervous system.

Form vision in the insect dorsal ocelli: an anatomical and optical analysis of the dragonfly median ocellus.

Previous work has suggested that dragonfly ocelli are specifically adapted to resolve horizontally extended features of the world, such as the horizon. We investigate the optical and anatomical properties of the median ocellus of Hemicordulia tau and Aeshna mixta to determine the extent to which the findings support this conclusion. Dragonfly median ocelli are shown to possess a number of remarkable properties: astigmatism arising from the elliptical shape of the lens is cancelled by the bilobed shape of the inner lens surface, interference microscopy reveals complex gradients of refractive index within the lens, the morphology of the retina results in zones of high acuity, and the eye has an exceedingly high sensitivity for a diurnal terrestrial invertebrate.

Form vision in the insect dorsal ocelli: an anatomical and optical analysis of the Locust Ocelli.

The dorsal ocelli are commonly considered to be incapable of form vision, primarily due to underfocused dioptrics. We investigate the extent to which this is true of the ocelli of the locust Locusta migratoria. Locust ocelli contain thick lenses with a pronounced concavity on the inner surface, and a deep clear zone separating retina and lens.