The 20th annual Symposium will be held on Thursday, April 23, 2009.

Penile Structure and Function in the Cavimorph Rodent Octodon degus
Norris 102, 1:45 PM

Alexander  McKelvy,   '10 49
   Major: Biology
   Hometown: Midland, MI

Sponsor(s): Tammy Jechura
Support:  

Abstract: 
Octodon degus, a social diurnal rodent from the western slopes of the Andes mountain range, exhibit interesting penile characters similar to other Cavimorph rodents, including pronged barbs on the length and long spikes on the distal end of the penis. It has recently been shown that the length, abundance, arrangement and color of these spikes are dependent on testosterone levels. The aim of this study is to determine whether the characteristic of the penile features provide some reproductive advantage through sperm competition among males. The spikes could have evolved to provide a means by which male degus could be more assured of paternity of offspring, possibly by being used for a copulatory lock mechanism, sperm removal device, mechanism for vaginal stimulation of the female resulting in induced ovulation, or some novel function. It’s also possible that they spikes are simply an evolutionary vestige that serve no true function. We are also examining the possibility that the number and size of spikes, which increase with increasing testosterone levels, are correlated with female mate choice.

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