Scent marking in the musk shrew (Suncus murinus)

Area of Science:

• Animal Behavior
• Endocrinology
• Mammalian Biology

Background:

• Scent marking is a crucial communication method in many mammal species.
• The hormonal basis of scent marking can vary significantly between sexes and species.
• Musk shrews (Suncus murinus) exhibit complex scent marking behaviors.

Purpose of the Study:

• To investigate the role of gonadal and adrenal hormones in regulating scent marking behaviors in male and female musk shrews.
• To determine if sexually monomorphic scent marking behaviors are under differential hormonal control in males and females.

Main Methods:

• Surgical manipulation including castration, ovariectomy, and adrenalectomy in adult musk shrews.
• Hormone replacement therapy with testosterone in castrated males.
• Quantification of the frequency of flank, perineal, and throat marking behaviors in experimental groups.

Main Results:

• In males, castration significantly reduced marking frequency, while testosterone administration restored perineal and throat marking.
• Female marking behavior was unaffected by ovariectomy, regardless of reproductive status (non-pregnant, pregnant, post-partum).
• In females, combined ovariectomy and adrenalectomy led to a significant decrease in flank and perineal marking, suggesting a role for adrenal hormones.

Conclusions:

• Scent marking behaviors in male musk shrews are primarily regulated by gonadal hormones (testosterone).
• In female musk shrews, flank and perineal marking are influenced by adrenal hormones, not gonadal steroids.
• Throat marking in female musk shrews appears to be independent of steroidal hormonal regulation.