Topographic organization of sensory afferents of Johnston's organ in the honeybee brain

Abstract

Johnston's organ (JO) in insects is a multicellular mechanosensory organ stimulated by movement of the distal part of the antenna. In honeybees JO is thought to be a primary sensor detecting air-particle movements caused by the waggling dance of conspecifics. In this study projection patterns of JO afferents within the brain were investigated. About 720 somata, distributed around the periphery of the second segment of the antenna (pedicel), were divided into three subgroups based on their soma location: an anterior group, a ventral group, and a dorsal group. These groups sent axons to different branches (N2 to N4) diverged from the antennal nerve. Dye injection into individual nerve branches revealed that all three groups of afferents, having fine collaterals in the dorsal lobe, sent axons broadly through tracts T6I, T6II, and T6III to terminate ipsilaterally in the medial posterior protocerebral lobe, the dorsal region of the subesophageal ganglion, and the central posterior protocerebral lobe, respectively. Within these termination fields only axon terminals running in T6I were characterized by thick processes with large varicosities. Differential staining using fluorescent dyes revealed that the axon terminals of the three groups were spatially segregated, especially in T6I, showing some degree of somatotopy. This spatial segregation was not observed in axon terminals running in other tracts. Our results show that projection patterns of JO afferents in the honeybee brain fundamentally resemble those in the dipteran brain. The possible roles of extensive termination fields of JO afferents in parallel processings of mechanosensory signals are discussed.

Influence of Different Statuses of Honey Bee Queens, Apis mellifera L. on the Ultrastructure of the Flagella on (3-Day Old) Workers

“…According to [71], the Johnson's organs, which, in the honeybee, perceive movement of antennal flagellum, response to movements of air and considered as flight speed indicator and this appeared in our results as there is no significant difference in the (Tr IV) in most status. [72] indicated, Sensilla Trichodea discribed as mechanosensory function with some also chemosensory and/or thermosensitive functions.…”

Antennal hearing in insects – New findings, new questions

“…The number of JO scolopidia varies widely across taxa; the JOs of Drosophila and honey bees, for example, harbour some 230e240 scolopidia Ai et al, 2007), whereas ca. 7000 scolopidia are found in the JO of mosquito males Richards, 1975a, 1975b).…”

“…7000 scolopidia are found in the JO of mosquito males Richards, 1975a, 1975b). Each JO scolopidium typically contains 2e3 primary mechanosensory neurons (Boo and Richards, 1975a, b;Todi et al, 2004;Ai et al, 2007) and a cap cell, a scolopale cell, and a ligament cell Yack, 2004). The sensory neurons are bipolar, bearing a proximal axon and an apical dendrite whose outer segment represents a cilium with a 9 Â 2 þ 0 axoneme (e.g.…”

NeuronDepot: keeping your colleagues in sync by combining modern cloud storage services, the local file system, and simple web applications

“…The hive-mates detect and process airborne vibration caused by the bee's wingbeat during the waggle dance, which consists of vibration pulses with a highly specific temporal pattern. Several critical interneurons for processing the airborne vibration have been identified (Ai et al, 2007, 2009; Ai, 2010; Ai and Itoh, 2012; Ai and Hagio, 2013). However, the neural processing of these vibration signals has rarely been studied: types and roles of neurons involved, their circuitry, and their development are largely unknown.…”