One explanation for the evolution of sexual monomorphism is the sexual indistinguishability hypothesis, which argues that in group-living species individuals might benefit by concealing their sex to reduce sexual competition. We tested this hypothesis in long-tailed finches Poephila acuticauda. Males and females could not be reliably distinguished morphologically or by analysis of the reflectance spectra (300-700 nm) from the plumage and bill. Males seemed unable to distinguish the sex of an unfamiliar individual in the absence of behavioural cues; they were equally likely to court and copulate with unfamiliar males and females but rarely courted familiar males. Here we report the first experimental evidence that sexual monomorphism enables strategic concealment of sex. Males were more likely to reveal their sex when faced with a solitary unfamiliar individual than a group of unfamiliar individuals. When encountering an unfamiliar male that revealed his sex, subordinate males were more likely to conceal their sex than dominant males.
A meeting of the Council on May 10th, 1832 resolved that abstracts of papers submitted for publication in the Philosophical Transactions from the year 1800 be published in Proceedings. By the 3rd volume the abstracts were arranged under the order in which the papers had been read at the meetings; the report of each discussion meeting was headed by a brief account of the business which preceded the reading of the papers. Included in the publication was the Anniversary meeting and reports. In 1905 the bulk of Proceedings increased so much that it split into two series: Series A (papers on the Mathematical, Physical and Engineering sciences) and Series B, (Biological sciences). Obituary Notices were printed in Proceedings up to April 1932 but since then have appeared as a separate publication. Proceedings are now published (A) once or twice (B) each month and include original papers of important new research findings and interesting reviews that shed new light on a particular subject or field.
The Royal Society is a self-governing Fellowship of many of the world's most distinguished scientists drawn from all areas of science, engineering and medicine, and is the oldest scientific academy in continuous existence. The Society’s fundamental purpose, reflected in its founding Charters of the 1660s, is to recognise, promote, and support excellence in science and to encourage the development and use of science for the benefit of humanity. The Society has played a part in some of the most fundamental, significant, and life-changing discoveries in scientific history and Royal Society scientists continue to make outstanding contributions to science in many research areas.