Postembryonic Development of the Central Nervous System in the Wolf Spider. Arctosa kwangreungensis (Araneae: Lycosidae)

Abstract

Microstructural characteristics of the central nervous system from postembryo to early instar spiderings in the wolf spider Arctosa kwangreungensis were studied using paraffine embedded tissue preparation and three dimensional image reconstruction techniques. The CNS of the postembryo was fully functional, despite its primitive microstructure. The CNS consists of a supraesophageal ganglion (brain) and a subesophageal mass, and they are joined with circumesophageal connectives. The brain of 1st instar spidering after a molt of the postembryo is also made up of a protocerebral and tritocerebral ganglion. Moreover, the subesophageal ganglionic mass is composed of a single pair of pedipalpal ganglia, four pairs of appendage ganglia, and a fused mass of abdominal neuromeres. For image processing and reconstruction, serially sectioned paraffin blocks were scanned with research complex microscopy and 3D images were reconstructed from the brain sections. The image stacks of the central complex and surrounding neuropils obtained from the brain sections were processed using Amira 5.3.2 software.