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Full-Text Articles in Animal Sciences
Left-Sided Directional Bias Of Cloacal Contacts During House Sparrow Copulations, Karen Nyland, Michael Lombardo, Patrick Thorpe
Left-Sided Directional Bias Of Cloacal Contacts During House Sparrow Copulations, Karen Nyland, Michael Lombardo, Patrick Thorpe
Michael P Lombardo
Most female birds have only a left ovary and associated oviduct. The entry to the oviduct is on the left side of the urodeum of the cloaca. This arrangement may favor males that mount females from the left during copulation if it results in sperm being placed closer to the opening of the oviduct. Therefore, we predicted a left-sided directional bias of cloacal contacts during House Sparrow (Passer domesticus) copulations. Cloacal contacts from the left outnumbered those from the right 74 to 25 (3:1) during 25 bouts of copulation at 11 House Sparrow nests. While this pattern suggests that a …
Within-Pair Copulations: Are Female Tree Swallows Feathering Their Own Nests?, Michael Lombardo
Within-Pair Copulations: Are Female Tree Swallows Feathering Their Own Nests?, Michael Lombardo
Michael P Lombardo
A variety of hypotheses has been proposed to explain why socially monogamous birds copulate repeatedly with their mates when only a single copulation is necessary to fertilize an entire clutch (Birkhead and Møller 1992, Petrie 1992, Hunter et al. 1993). Petrie (1992) hypothesized that a female should copulate frequently with her mate so as to reduce her mate’s involvement in extrapair copulations. By reducing her mate’s involvement in extrapair copulations, a female may: (1) avoid the transmission of parasites and sexually transmitted diseases (Hamilton 1990); (2) may avoid sperm depletion by her mate; and (3) may monopolize her mate’s paternal …
Left-Sided Directional Bias Of Cloacal Contacts During Tree Swallow Copulations, Aaron Petersen, Michael Lombardo, Harry Power
Left-Sided Directional Bias Of Cloacal Contacts During Tree Swallow Copulations, Aaron Petersen, Michael Lombardo, Harry Power
Michael P Lombardo
Most female birds have only a left ovary and associated oviduct with entry to the oviduct on the left side of the urodeum of the cloaca. We hypothesized that male cloacal contacts during copulation would occur from the left side of females because this would put sperm closer to the entrance of the oviduct. We observed that cloacal contacts from the left outnumbered those from the right by a margin of 3:1 during tree swallow, Tachycineta bicolor, copulations at nestboxes in western Michigan in 1999. The directional bias of cloacal contacts may have an adaptive function.