Observations on the structure and function of the seminal receptacles and associated accessory pouches in ovoviviparous onychophorans from Australia (Peripatopsidae ; Onchophora)

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Title: Observations on the structure and function of the seminal receptacles and associated accessory pouches in ovoviviparous onychophorans from Australia (Peripatopsidae ; Onchophora)
Related: Journal of zoology, Vol. 270, Issue 3, p.531-542
DOI: 10.1111/j.1469-7998.2006.00121.x
Publisher: Blackwell Publishing
Date: 2006
Author/Creator: Walker, M. H
Author/Creator: Roberts, E. M
Author/Creator: Roberts, T
Author/Creator: Spitteri, G
Author/Creator: Streubig, M. J
Author/Creator: Hartland, J. L
Author/Creator: Tait, N. N
Description: The structure of the seminal receptacles and associated accessory pouches in the reproductive tracts of four species of Australian ovoviviparous peripatopsids is described to identify features that may relate to their inferred mode of insemination. "Euperipatoides rowelli" is a dermal inseminator whereas "Phallocephale tallagandensis", "Ruhbergia bifalcata" and "Cephalofovea clandestina", species with head structures in males, are considered to be vaginal inseminators. Contrary to our expectations, "E. rowelli", "R. bifalcata" and "C. clandestina" have very similar seminal receptacles and display two types of accessory pouches: funnel accessory pouches that open to the haemocoel and spherical accessory pouches in which destruction of excess sperm occurs. On the other hand, "Ph. tallagandensis" differs in the form of its accessory pouches. Although these pouches have no direct opening into the haemocoel, sperm were observed in the act of directly penetrating their walls to gain entry from the haemocoel. Hence, despite differences in the form of their accessory pouches, all species display features that provide the potential for entry of sperm into the female reproductive tract from the haemocoel. This finding has caused us to reconsider our initial assumptions of vaginal and dermal insemination as mutually exclusive reproductive strategies. Indeed, we propose that species of peripatopsids with head structures in males that were considered to be obligate vaginal inseminators may in fact be facultative, with vaginal insemination of sexually immature females when their uterus is short and free of developing embryos followed by dermal insemination to maintain the level of sperm in storage in the seminal receptacles. This study has also provided morphological evidence for mechanisms that may facilitate female control of paternity.
Description: 12 page(s)
Subject Keyword: 060800 Zoology
Subject Keyword: Onychophora
Subject Keyword: Peripatopsidae
Subject Keyword: seminal receptacles
Subject Keyword: accessory pouches
Subject Keyword: insemination
Subject Keyword: female control of paternity
Resource Type: journal article
Organisation: Macquarie University. Department of Biological Sciences

Identifier: http://hdl.handle.net/1959.14/13317
Identifier: mq:1497
Identifier: ISSN:0952-8369
Identifier: mq-rm-2006005781
Language: eng

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