FORMATION, TRANSFER, AND ASSIMILATION OF THE SPERMATOPHORE OF THE HERMAPHRODITIC FLATWORM DUGESIA-GONOCEPHALA (TRICLADIDA, PALUDICOLA)

Citation
C. Vreys et al., FORMATION, TRANSFER, AND ASSIMILATION OF THE SPERMATOPHORE OF THE HERMAPHRODITIC FLATWORM DUGESIA-GONOCEPHALA (TRICLADIDA, PALUDICOLA), Canadian journal of zoology, 75(9), 1997, pp. 1479-1486
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Zoology
Journal title
ISSN journal
0008-4301
Volume
75
Issue
9
Year of publication
1997
Pages
1479 - 1486
Database
ISI
SICI code
0008-4301(1997)75:9<1479:FTAAOT>2.0.ZU;2-O
Abstract
The spermatophore of the simultaneously hermaphroditic planarian Duges ia gonocephala consists of a large stalked bladder that gradually form s inside the ejaculatory duct of the penis between successive copulati ons. In solitary individuals, spermatophore formation begins with the development in the penis of a tube that is sealed at the distal end an d may protrude slightly from the penis tip. In courting individuals, t his protruding part is widened into a bladder that further increases i n size when penises are mutually inserted. Spermatozoa are pumped into the bladder after the first few minutes of copulation and the resulta nt spermatophores are exchanged 3-4 1/2 h after the start of copulatio n. Reciprocal transfer is slightly asynchronous. After the spermatopho re is transferred into the bursa copulatrix, the stalk of the spermato phore is usually in or near the entrance to the bursal canal. Sperm st art to leave the spermatophore immediately after the partners separate and continue to do so for 3-4 days. During this period, the bladder o f the spermatophore shrinks but remains intact. Following spermatophor e donation, the penis may hold a new spermatophore after 1-2 days. Ind ividuals that engage in a new copulation rarely do so because they are allosperm depleted. In fact, the bursa may still hold a spermatophore from a previous copulation. We discuss the adaptive significance of s permatophore formation, transfer, and assimilation.