title: Bicephality, a seldom occurring developmental deformity in Tegenaria atrica caused by alternating temperatures.
abstract: The experiment was aimed at demonstrating the relationship between deformities of the front part of the prosoma accompanied by changes in the brain structure in bicephalous Tegenaria atrica and exposure of their embryos to temperature fluctuations. By exposing spider embryos to alternating temperatures of 14 and 32°C for the first 10 days of embryonic development, we obtained eight two-headed individuals, subsequently divided into three groups according to morphological differences. We described in detail morphological abnormalities of the prosoma identified in members of each group. Histological examination confirmed a close relationship between morphological deformities and the brain structure of teratogenically changed spiders. The fusion of appendages (pedipalps and chalicerae) was accompanied by the fusion of corresponding ganglia. The absence of appendages (pedipalps) was accompanied by the absence of corresponding ganglia. This correlation may have resulted from previously impaired neuromere development which led to changes in the morphological structure of the prosoma. Since no deformities were identified in control animals, it can be concluded that bicephaly was caused by exposing embryos to alternating temperatures.
authors: Department of Invertebrate Zoology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Toruń, Poland. Electronic address: tnapiork@umk.pl.
authors: Teresa
authors: T
authors: Napiórkowska
authors: Department of Hydrobiology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Toruń, Poland.
authors: Paweł
authors: P
authors: Napiórkowski
authors: Department of Invertebrate Zoology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Toruń, Poland.
authors: Julita
authors: J
authors: Templin
authors: Department of Vertebrate Zoology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, 87-100 Toruń, Lwowska 1, Poland.
authors: Katarzyna
authors: K
authors: Wołczuk
mesh_terms: D000818:Animals; D001921:Brain / Q000002:abnormalities / Q000196:embryology; D004625:Embryo, Nonmammalian / Q000002:abnormalities*; D005260:Female; D008297:Male; D013112:Spiders / Q000033:anatomy & histology* / Q000196:embryology*; D013696:Temperature
keywords: Alternating temperatures; Bicephalous spider; Brain; Malformation