Anti-predator behaviour of the red-legged partridge Alectoris rufa (Galliformes: Phasianidae) to simulated terrestrial and aerial predators

This study is intended to investigate the differences in anti-predator behavioural and acoustic response to terrestrial and aerial predators as well as the behavioural differences between sexes in the red-legged partridge. To this aim we observed the response of 114 partridge (57 males and 57 females) to dummy terrestrial and aerial predators, a raptor and a fox. We divided behavioural responses to predators into four mutually exclusive categories: vigilance, freezing, escape and non-anti-predator behaviours. We also recorded and analysed the vocalizations emitted during tests. The animals reacted differently to aerial and terrestrial stimuli. The reactions elicited by the terrestrial predator were ranked as follows: vigilance, escape, non-anti-predator behaviours, and freezing. Those elicited by the aerial predator were ranked as follows: vigilance, freezing, escape and non-anti-predator behaviours. Vigilance and escape were elicited more frequently by the terrestrial predator than by the aerial predator (vigilance: p 0.001; escape: p 0.001). Freezing was the most frequent behaviour following the appearance of the aerial predator (p 0.001). In fact, freezing may represent an effective strategy in an open space, combining camouflage from and detection by the predator. On the other hand, vigilance is an effective behaviour to detect and avoid a terrestrial predator hunting by ambush. We did not find clear-cut differences between sexes. The analysis of vocalizations revealed that the fox and the raptor elicited significantly different calls (p = 0.003); the fox evoked significantly more vocalizations than the raptor (p 0.001), differing in addition in frequency parameters. Thus partridges not only discriminate between aerial and terrestrial predators and behave consequently, but are also able to tune alarm calls in relation to the context of predation

The biological impact of blood pressure-associated genetic variants in the natriuretic peptide receptor C gene on human vascular smooth muscle.

Elevated blood pressure (BP) is a major global risk factor for cardiovascular disease. Genome-wide association studies have identified several genetic variants at the NPR3 locus associated with BP, but the functional impact of these variants remains to be determined. Here we confirmed, by a genome-wide association study within UK Biobank, the existence of two independent BP-related signals within NPR3 locus. Using human primary vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) from different individuals, we found that the BP-elevating alleles within one linkage disequilibrium block identified by the sentinel variant rs1173771 was associated with lower endogenous NPR3 mRNA and protein levels in VSMCs, together with reduced levels in open chromatin and nuclear protein binding. The BP-elevating alleles also increased VSMC proliferation, angiotensin II-induced calcium flux and cell contraction. However, an analogous genotype-dependent association was not observed in vascular ECs. Our study identifies novel, putative mechanisms for BP-associated variants at the NPR3 locus to elevate BP, further strengthening the case for targeting NPR-C as a therapeutic approach for hypertension and cardiovascular disease prevention

Gestational Exposure to Low Dose Bisphenol A Alters Social Behavior in Juvenile Mice

Bisphenol A (BPA) is a man-made compound used to make polycarbonate plastics and epoxy resins; public health concerns have been fueled by findings that BPA exposure can reduce sex differences in brain and some behaviors. We asked if a low BPA dose, within the range measured in humans, ingested during pregnancy, would affect social behaviors in prepubertal mice. We noted sex differences in social interactions whereby females spent more time sitting side-by-side, while males engaged in more exploring and sitting alone. In addition BPA increased display of nose-to-nose contacts, play solicitations and approaches in both sexes. Interactions between sex and diet were found for self grooming, social interactions while sitting side-by-side and following the other mouse. In all these cases interactions were produced by differences between control and BPA females. We examined brains from embryos during late gestation to determine if gene expression differences might be correlated with some of the sexually dimorphic or BPA affected behaviors we observed. Because BPA treatments ended at birth we took the brains during embryogenesis to increase the probability of discovering BPA mediated effects. We also selected this embryonic age (E18.5) because it coincides with the onset of sexual differentiation of the brain. Interestingly, mRNA for the glutamate transporter, Slc1a1, was enhanced by exposure to BPA in female brains. Also we noted that BPA changed the expression of two of the three DNA methyltransferase genes, Dnmt1 and Dnmt3a. We propose that BPA affects DNA methylation of Sc1a1 during neural development. Sex differences in juvenile social interactions are affected by BPA and in particular this compound modifies behavior in females

WATTLE SIZE IS CORRELATED WITH MALE TERRITORIAL RANK IN JUVENILE RING-NECKED PHEASANTS

We used morphological measurements and behavioral observations to investigate the relationship between male ornaments and male social rank during the breeding season in a free-ranging population of one-year-old Ring-necked Pheasants (Phasianus colchicus). The sample was of birds of the same age class to avoid the confounding effect of age differences. Tail length, used by females in mate choice, and tarsal spur length, used by males as a weapon in fights, were not correlated with male rank, whereas the size of the wattle was the most important trait. This combined with recent studies showing that wattle size reliably indicates male testosterone levels at the beginning of the breeding season suggest that, among males, wattle size may be used as a signal of aggression level, and body condition. Utilizamos medidas morfológicas y observaciones de comportamiento para investigar la relación entre los ornamentos de los machos y el rango social de éstos durante la época reproductiva en una población silvestre de faisanes Phasianus colchicus de un año de edad. La muestra consistió´ de aves de la misma clase de edad para evitar el efecto de diferencias entre edades. La longitud de la cola (utilizada por las hembras en la selección de pareja) y la longitud de la espuela tarsal (utilizada por los machos como un arma en enfrentamientos) no se correlacionaron con el rango de los machos, mientras que el tamaño de la carúncula fue el caracter más importante. En combinación con estudios recientes que muestran que el tamaño de la carúncula indica confiablemente los niveles de testosterona en los machos al inicio de la época reproductiva, esto sugiere que el tamaño de la carúncula podría ser usado como una señal de niveles de agresión y condición corporal entre los machos

Testosterone Affects The Acoustic Structure Of The Male Call In The Grey Partridge (Perdix Perdix)

The effects of testosterone (T) on the acoustic features of the ''rusty-gate'' call of the grey partridge, a non-oscine bird, were studied in 24 males kept in semi-natural conditions. Half of them were implanted subcutaneously with T propionate in Silastic tubes at 10 weeks of age, the remaining were sham operated as controls. After one month implanted males showed significantly higher T levels than controls, while treatment did not affect body size. Individual recordings of calls were analysed and accurate measurements were taken by a digital spectrograph. The duration of calls was significantly greater in T-males than in controls. A similar lengthening has been described in nature in spring, when plasma levels of androgens rise. The frequencies of the most intense portion of the call ranged more widely and had a lower minimum in T-males than in controls, suggesting an hormonal control on call system at the peripheral/central level. In conclusion T affects specific temporal and frequency features of the male calls. The relationship between T and call structure could enable females to assess quality and sexual motivation of their potential mates