Sexual arousal, is it for mammals only?

Area of Science:

• Ethology
• Neuroscience
• Comparative Physiology

Background:

• Defining and measuring sexual arousal varies across species.
• Mammalian sexual arousal is often inferred from penile erection.
• Assessing sexual arousal in non-mammalian species, particularly birds, remains under-addressed.

Purpose of the Study:

• To identify suitable measures for assessing sexual arousal in birds.
• To explore behavioral and physiological indicators of sexual arousal in avian species.
• To compare arousal assessment methods between mammals and birds.

Main Methods:

• Studied male Japanese quail to identify arousal indicators.
• Observed appetitive sexual behaviors preceding copulation.
• Measured brain activation using immediate early gene expression (fos, egr-1) and 2-deoxyglucose autoradiography.
• Quantified dopamine release in the medial preoptic area via in vivo dialysis.

Main Results:

• Appetitive sexual behavior, specific brain activation, and medial preoptic dopamine release are viable indicators of sexual arousal in birds.
• These criteria allow for the assessment of sexual arousal in its broadest sense in avian species.
• Directly matching mammalian criteria (penile erection) for arousal assessment remains difficult in birds without advanced imaging.

Conclusions:

• Behavioral and neurophysiological measures provide a framework for assessing sexual arousal in birds.
• Dopamine release in the medial preoptic area is a key indicator of sexual arousal in male Japanese quail.
• Future advancements in in vivo imaging techniques may enable more direct comparisons of sexual arousal mechanisms across species with and without intromittent organs.