The Central Nervous System of Heterosymelic Individuals of the Spider Tegenaria atrica

Abstract

This paper presents the results of research on the nervous system in individuals of Tegenaria atrica with heterosymely of walking legs, a pedipalp and the first walking leg. Temperatures alternating between 14 degrees and 32 degrees C every 12 hours were applied as a teratogenic factor in the early stage of embryogenesis. From the thus obtained specimens, histological sections were taken using the paraffin method and then stained. Analysis of the nervous system in individuals with partial heterosymely of walking legs showed no significant changes in the structure of subesophageal nervous mass. In most of the studied individuals with partial and total heterosymely of a pedipalp and walking leg no changes were observed in the relevant parts of the nervous system either, although in two cases a fusion of nerve ganglia was noted, from which the nerves branched off towards the conjoined legs.

Morphological and anatomical changes related to leg anomalies in Tegenaria atrica

“…Structural changes in the fused suboesophageal ganglia were previously recorded in different cases of oligomely (Jacuński et al 2005) and heterosymely (Napiórkowska et al 2013) of T. atrica . However, no information is available about defects of the nervous system of spiders affected by multiple anomalies.…”

“…Although an additional ganglion was identified, there was no additional venom gland associated with the additional chelicerae. Jacuński et al (2002) and Napiórkowska et al (2013) performed morphological and anatomical analysis of spiders with partial and total heterosymely of appendages. Despite the fact that they were fused, no changes in the position or shape of the ganglia which innervated them were noticed.…”

“…Internal deformities are found mainly in the digestive system and the central nervous system (Jacuński 1983; Jacuński et al 2002, 2005; Napiórkowska et al 2006, 2010, 2013). The central nervous system of Poecilotheria and Argiope aurantia (Lucas) was described in detail by Babu (1965, 1969, 1975).…”

Morphology and the central nervous system of Eratigena atrica affected by a complex anomaly in the anterior part of the prosoma

“…Complete and partial heterosymely of appendages was reflected in the CNS in two ways: (1) in the majority of investigated heterosymelic individuals (52) nerve ganglia were not fused, (2) only in two cases, heterosymely of the pedipalps and walking legs was connected with the fusion of corresponding ganglia (Napiórkowska et al 2013b). Similar phenomenon accompanied polymely of walking legs (Napiórkowska et al 2015).…”

“…Studies which provide analysis of these changes are extremely important because they facilitate the classification of the obtained deformity. It must be remembered that morphological changes are not always reflected in the structure of internal systems, as has already been demonstrated by Jacuński et al (2002a), Napiórkowska et al (2013b, 2015), who studied Eratigena atrica (previous name: Tegenaria atrica) . In order to evaluate changes in the CNS of teratogenically affected Eratigena atrica, we therefore included histological analysis in the present study.…”