Effects of sexual pairing pattern on behaviour and reproductive performance in domestic pigeons

Same sexual pairing is a widespread but complex phenomenon across a variety of animal groups. However, previous research on its behaviours and potential mechanisms has been limited by small sample sizes and inconsistent experimental conditions. The purpose of this study was to explore the effects of different sexual pairing patterns on the reproductive performance, behaviour dynamics, and plasma reproductive hormone profile of pigeons. During the 270-day experimental observation period, the performance of female-male (FM) pairing and female-female (FF) pairing was systematically compared. The results showed that compared with FM pairing, the average monthly egg production per female of FF pairing was significantly lower (2.98 ± 0.07 vs. 3.84 ± 0.08 eggs/female/month; P < 0.05). However, no significant differences were observed in the single egg rate and egg weight. Behavioural analysis showed that the frequency of nesting behaviour in FF pairing was significantly higher, but the frequency of walking, allopreening, and courtship feeding was lower than that in FF pairing (P < 0.05). The results of hormone determination showed that in the post-oviposition period, the concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E₂) in plasma gradually increased, while the levels of prolactin (PRL) decreased. Compared with FM pairing, FF pairing showed significantly higher PRL concentration in the late period of egg-laying interval (P < 0.05). These findings suggest that pairing patterns regulate hypothalamic-pituitary-gonadal (HPG) axis activity and affect reproductive outcomes by modulating responses to social stimuli. The study provides insights into the endocrine and behavioural mechanisms underlying different sexual pairing patterns in pigeons and supports the potential application of FF pairing as an alternative production strategy in pigeon production.