Identification of the baculum in American pika (<i>Ochotona princeps</i>: Lagomorpha) from southwestern Alberta, Canada

Weimann, Bill; Edwards, Mark; Jass, Christopher N.

doi:10.1644/13-mamm-a-165

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…It was thought only to exist in eight of the mammalian orders: Afrosoricida, Carnivora, Chiroptera, Dermoptera, Erinaceomorpha, Primates, Rodentia and Soricomorpha [3,4]. However, it has recently been discovered that a Lagomorph, the American pika ( Ochonta princeps ), also has a small baculum [5]. This discovery suggests that baculum presence may be more prevalent across mammals than historically assumed.…”

Section: Introductionmentioning

confidence: 99%

Postcopulatory sexual selection influences baculum evolution in primates and carnivores

Brindle¹,

Opie²

2016

Proc. R. Soc. B.

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The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection (particularly, high levels of postcopulatory selection). However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here, we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection.

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Section: Introductionmentioning

confidence: 99%

Postcopulatory sexual selection influences baculum evolution in primates and carnivores

Brindle¹,

Opie²

2016

Proc. R. Soc. B.

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“…Most GBiF sites were not selected because they were within 3 km of an already chosen site; the coordinates were apparently estimated from general, verbal descriptions; or site examination using Google earth suggested that it was unlikely pika habitat. Location data cited in Weimann et al (2014) provided six additional sites for southwestern Alberta, separated by 3 km or more. Locations of the 114 sites are shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Are American Pikas (<em>Ochotona princeps</em>) in the Canadian Rockies vulnerable to climate change?

Shank

2015

Can Field Nat

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The American Pika (Ochotona princeps) is vulnerable to climate change as a result of its dependence on cool, moist conditions. Most research on climatic determinants of American Pika distribution has been done in the United States where conditions are different from those in the higher-latitude pika ranges of the Canadian Rockies. I examined recent (1980–2009) and future (2050s and 2080s) average and maximum mean summer temperatures for 114 current American Pika locations in Alberta to assess whether future conditions are likely to place these animals at risk. At all current sites, mean summer temperatures (MSTs) in the 2050s are expected to be below that chosen by the United States Fish and Wildlife Service as a threshold for at-risk status of O. princeps. By the 2050s, most current American Pika locations have sufficient elevation within 5 km to allow individuals to migrate vertically to reach habitat with MST similar to that of their current location. Even in the 2080s, almost all current sites have sufficient elevation within 5 km to maintain extreme single-year and average MSTs lower than the highest values recorded at those sites in the recent past (13.9°C and 12.5°C respectively). However, by the 2080s under an extreme greenhouse gas emissions scenario, only 34% of current pika sites will allow for such migration. Although considerable uncertainty remains, particularly with respect to availability of habitat, these results suggest that American Pika populations in Alberta will likely be capable of persisting throughout this century, although their survival will depend increasingly on successful vertical migration.

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“…The baculum (or os penis) is a mineralized bone located within the glans of the mammalian penis. The baculum is considered one of the most morphologically diverse bones within the mammalian skeleton [ 1 , 2 ] and its presence has been documented across nine modern Orders: Afrosoricida, Carnivora, Chiroptera, Dermoptera, Erinaceomorpha, Lagomorpha, Primates, Rodentia and Soricomorpha [ 3 , 4 ]. Yet, the evolutionary history of the baculum has only recently been resolved following the application of modern phylogenetic techniques [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Testing hypotheses for the function of the carnivoran baculum using finite-element analysis

2018

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The baculum (os penis) is a mineralized bone within the glans of the mammalian penis and is one of the most morphologically diverse structures in the mammal skeleton. Recent experimental work provides compelling evidence for sexual selection shaping the baculum, yet the functional mechanism by which this occurs remains unknown. Previous studies have tested biomechanical hypotheses for the role of the baculum based on simple metrics such as length and diameter, ignoring the wealth of additional shape complexity present. For the first time, to our knowledge, we apply a computational simulation approach (finite-element analysis; FEA) to quantify the three-dimensional biomechanical performance of carnivoran bacula (n = 74) based upon high-resolution micro-computed tomography scans. We find a marginally significant positive correlation between sexual size dimorphism and baculum stress under compressive loading, counter to the ‘vaginal friction’ hypothesis of bacula becoming more robust to overcome resistance during initial intromission. However, a highly significant negative relationship exists between intromission duration and baculum stress under dorsoventral bending. Furthermore, additional FEA simulations confirm that the presence of a ventral groove would reduce deformation of the urethra. We take this as evidence in support of the ‘prolonged intromission’ hypothesis, suggesting the carnivoran baculum has evolved in response to pressures on the duration of copulation and protection of the urethra.

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Identification of the baculum in American pika (Ochotona princeps: Lagomorpha) from southwestern Alberta, Canada

Cited by 10 publications

References 22 publications

Postcopulatory sexual selection influences baculum evolution in primates and carnivores

Postcopulatory sexual selection influences baculum evolution in primates and carnivores

Are American Pikas (<em>Ochotona princeps</em>) in the Canadian Rockies vulnerable to climate change?

Testing hypotheses for the function of the carnivoran baculum using finite-element analysis

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