title: Sperm dynamics in spiders (Araneae): ultrastructural analysis of the sperm activation process in the garden spider Argiope bruennichi (Scopoli, 1772).
abstract: Storage of sperm inside the female genital tract is an integral phase of reproduction in many animal species. The sperm storage site constitutes the arena for sperm activation, sperm competition and female sperm choice. Consequently, to understand animal mating systems information on the processes that occur from sperm transfer to fertilization is required. Here, we focus on sperm activation in spiders. Male spiders produce sperm whose cell components are coiled within the sperm cell and that are surrounded by a proteinaceous sheath. These inactive and encapsulated sperm are transferred to the female spermathecae where they are stored for later fertilization. We analyzed the ultrastructural changes of sperm cells during residency time in the female genital system of the orb-web spider Argiope bruennichi. We found three clearly distinguishable sperm conditions: encapsulated sperm (secretion sheath present), decapsulated (secretion sheath absent) and uncoiled sperm (cell components uncoiled, presumably activated). After insemination, sperm remain in the encapsulated condition for several days and become decapsulated after variable periods of time. A variable portion of the decapsulated sperm transforms rapidly to the uncoiled condition resulting in a simultaneous occurrence of decapsulated and uncoiled sperm. After oviposition, only decapsulated and uncoiled sperm are left in the spermathecae, strongly suggesting that the activation process is not reversible. Furthermore, we found four different types of secretion in the spermathecae which might play a role in the decapsulation and activation process.
authors.affiliation: University of Greifswald, Zoological Institute and Museum, Department of General and Systematic Zoology, Greifswald, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Vöcking
authors.forename: Gabriele
authors.initials: G
authors.lastname: Uhl
authors.forename: Peter
authors.initials: P
authors.lastname: Michalik
mesh_terms: D000818:Animals; D048430:Cell Shape; D005260:Female; D005836:Genitalia, Female / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D013094:Spermatozoa / Q000502:physiology / Q000648:ultrastructure*; D013112:Spiders / Q000166:cytology*
references.citation: Annu Rev Entomol. 2007;52:351-74
references.pmid: 16968204
references.citation: J Morphol. 2005 Jan;263(1):118-32
references.pmid: 15562503
references.citation: Biol Rev Camb Philos Soc. 2008 May;83(2):191-208
references.pmid: 18397179
references.citation: Zoology (Jena). 2006;109(1):14-25
references.pmid: 16386412
references.citation: Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6261-6
references.pmid: 15071179
references.citation: J Insect Physiol. 2007 Apr;53(4):319-31
references.pmid: 17276455
references.citation: J Morphol. 2005 Mar;263(3):284-309
references.pmid: 15672391
references.citation: J Cell Biol. 1963 Apr;17:208-12
references.pmid: 13986422
references.citation: Biol Rev Camb Philos Soc. 2011 Feb;86(1):249-70
references.pmid: 20608927
references.citation: J Struct Biol. 2003 May;142(2):311-8
references.pmid: 12713959
references.citation: J Morphol. 2008 Apr;269(4):464-78
references.pmid: 18157861
references.citation: Front Zool. 2005 Jun 29;2(1):12
references.pmid: 15987506
references.citation: J Morphol. 2008 Sep;269(9):1122-33
references.pmid: 18553422
references.citation: Proc Biol Sci. 2004 May 7;271 Suppl 4:S134-7
references.pmid: 15252964
references.citation: J Ultrastruct Res. 1969 Jan;26(1):31-43
references.pmid: 4887011
references.citation: Peptides. 2004 Sep;25(9):1477-90
references.pmid: 15374649