Ultrastructure of the contact chemoreceptors of Apis mellifera L. (Hymenoptera : Apidae)

Abstract

Sensilla chaetica of different sizes were found by scanning electron microscopy on the glossa, labial palps, galeae, antennae and tarsi of the worker honey bee. Sensilla basiconica also were found on these structures, except the antennae and glossa. With the exception of the mandibles, whose sensilla are all innervated by one sensory neuron, transmission electron microscope studies showed these receptors are similar in ultrastructure to taste receptors previously described in other insects. It was determined that sensilla on the mouthparts and tarsi possess 5 sensory neurons, one of which ends at the sensilla base as a mechanoreceptor, the other 4 extending up the lumen of a two-chambered hair. Many of the sensilla are tipped with either a pore or a papilla. About half of the sensilla observed on the antennae are innervated by 6 sensory neurons. A peculiarly shaped sensillum trichodeum occurs on the mandible which breaks off at pupal eclosion. A spatulate peg on the tarsal claw is also present.