Bioactivity of beaver castoreum constituents using principal components analysis

Area of Science:

• Behavioral Ecology
• Chemical Ecology
• Mammalian Biology

Background:

• North American beaver (Castor canadensis) utilize castoreum as a crucial social and territorial chemosignal.
• Previous studies assessed beaver responses to castoreum components individually, lacking a composite measure of bioactivity.
• Understanding the full behavioral repertoire elicited by castoreum is vital for interpreting beaver communication.

Purpose of the Study:

• To develop a composite measure of biological activity for synthetic castoreum components.
• To compare the bioactivity of synthetic castoreum components with natural castoreum using principal components analysis (PCA).
• To investigate family unit responses to castoreum signals.

Main Methods:

• Observed and quantified beaver responses including sniffing, land visits, and visitation duration to experimental scent mounds (ESM).
• Utilized principal components analysis (PCA) to integrate six measures of observed response and overnight visitation data.
• Compared responses to synthetic compounds with those elicited by natural castoreum control.

Main Results:

• The first principal component (PC) derived from PCA explained most variation, enabling a composite bioactivity ranking of samples.
• A second PCA on response trials indicated synthetic samples elicited less complete and weaker responses compared to natural castoreum.
• Natural castoreum elicited significantly more multiple land visits, suggesting family-level signaling.

Conclusions:

• Principal components analysis (PCA) provides a robust method for assessing the composite bioactivity of chemical signals.
• Synthetic components, while eliciting responses, do not fully replicate the complex signaling of natural castoreum.
• Interpreting beaver chemosignals necessitates considering the family unit's collective response, not just initial individual interactions.