Interspecific territoriality may play an important role in structuring ecological communities, but the causes of this widespread form of interference competition remain poorly understood. Here, we investigate the phenotypic, ecological and phylogenetic correlates of interspecific territoriality in wood warblers (Parulidae). Interspecifically territorial species have more recent common ancestors...

—The Homerus Swallowtail, Papilio (Pterourus) homerus, is an endangered butterfly endemic to Jamaica. We report conspecific male interactions observed in the Cockpit Country. Field observations of the patrolling behavior and the conspecific male circular flights suggest that males are territorial. Unlike most previous reports of male butterfly territoriality, physical contact occurs in the male...

In vertebrates, circulating androgen levels are regulated by the hypothalamic-pituitary-gonadal (HPG) axis through which the brain controls the gonads via the pituitary. Androgen levels ultimately depend on factors including season, temperature, social circumstance, age, and other variables related to reproductive capacity and opportunity. Previous studies with an African cichlid fish, Astatoti...

In diploid animals, males and females share most of the genome (except sex-specific elements, such as sex chromosome genes), yet despite sharing the underlying genes that hard-wire traits, males and females may differ in their phenotypes when traits are controlled by proximate mechanisms, such as hormones. In color polymorphic species where coloration is only expressed in one sex, the design of...

Androgen hormones have been shown to facilitate competitive ability in courtship and territorial behavior, while suppressing paternal behavior. The rock-pool blenny, Parablennius parvicornis, provides an excellent model to study the proximate regulation of such a trade-off between territorial and parental behavior, because nest-holder males of this species display these behaviors simultaneously...

The sexual selection strategies of territorial Odonata that do not present courtship behavior is still not completely understood, especially the role of the females. Diastatops obscura Fabricius (Odonata: Libellulidae) females participate in mate selection in a passive manner, allowing copulation with the first male that captures them and afterwards choosing whether to oviposit or not. This stu...

Males of Chrysozephyrus smaragdinus were active from late morning to late afternoon, during which they showed territorial behavior, perhaps for mating. The territorial male stayed in a particular area and occasionally flew around it, referred to hereafter as the inspection area. When other male intruded into this area, the territorial male rushed to him. Then, they engaged in a circling flight ...

OBJECTIVE Our purpose was to determine the usefulness of single-axis diffusion-weighted imaging versus trace diffusion-weighted imaging in the evaluation of cerebral infarctions. SUBJECTS AND METHODS Twenty-six patients harboring 34 infarctions were examined using single-axis and trace diffusion-weighted imaging within 48 hr of the onset of symptoms. Two neuroradiologists who were not aware o...

BACKGROUND Male song sparrows (Melospiza melodia) are territorial year-round; however, neuroendocrine responses to simulated territorial intrusion (STI) differ between breeding (spring) and non-breeding seasons (autumn). In spring, exposure to STI leads to increases in luteinizing hormone and testosterone, but not in autumn. These observations suggest that there are fundamental differences in t...

Vertebrates show a diverse array of social behaviors associated with territoriality. Field and laboratory experiments indicate that underlying themes-including mechanisms-may exist. For example in birds, extensive evidence over many decades has implicated a role for testosterone in the activation of territorial aggression in reproductive contexts. Territoriality at other times of the year appea...