Corticosterone regulation in house sparrows invading Senegal

Area of Science:

• Ecology
• Physiology
• Endocrinology

Background:

• Organismal range expansion is influenced by various traits, but physiological and endocrinological factors are understudied.
• Corticosterone (CORT) is a key stress hormone, and its role in invasion biology is largely unexplored.
• Previous work in house sparrows in Kenya indicated stronger CORT responses at invasion range edges.

Purpose of the Study:

• To investigate if stress hormone regulation patterns observed in Kenya are replicated in a separate, more recent house sparrow invasion in Senegal.
• To determine the role of corticosterone (CORT) in mediating range expansion.
• To explore potential biomarkers for invasion risk.

Main Methods:

• Comparing corticosterone (CORT) responses to restraint stress in house sparrows from range-edge and core populations in Senegal.
• Measuring baseline CORT levels in Senegalese house sparrows.
• Analyzing the influence of sex, body mass, and body size on CORT levels.

Main Results:

• House sparrows at the Senegal range edge exhibited stronger CORT responses to stress compared to core populations.
• Lower baseline CORT levels were observed in range-edge birds than in core birds.
• Individual sex, body mass, or body size did not significantly affect CORT levels.

Conclusions:

• The findings suggest that glucocorticoid regulation, specifically stress hormone responses, may play a role in facilitating range expansion.
• Stress response patterns observed in Kenya were mirrored in the independent Senegal invasion.
• Corticosterone regulation is implicated as a mediator of range expansion success, with stress responses potentially serving as biomarkers for invasion risk.