Roldán, C. T. Ausín y R. Mate, Guerra y Paz. En nombre de la política. Madrid, El rapto de Europa, 2004, pp. 349

Fil: Ercoli, César Adrián. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Ultraviolet plumage colors predict mate preferences in starlings

Avian plumage has long been used to test theories of sexual selection, with humans assessing the colors. However, many birds see in the ultraviolet (<400 nm), to which humans are blind. Consequently, it is important to know whether natural variation in UV reflectance from plumage functions in sexual signaling. We show that female starlings rank males differently when UV wavelengths are present or absent. Principal component analysis of ≈1300 reflectance spectra (300–700 nm) taken from sexually dimorphic plumage regions of males predicted preference under the UV+ treatment. Under UV− conditions, females ranked males in a different and nonrandom order, but plumage reflectance in the human visible spectrum did not predict choice. Natural variation in UV reflectance is thus important in avian mate assessment, and the prevailing light environment can have profound effects on observed mating preferences.

Interface between culturally based preferences and genetic preferences: female mate choice in Poecilia reticulata.

The relative contribution of genetic and socio-cultural factors in the shaping of behavior is of fundamental importance to biologists and social scientists, yet it has proven to be extremely difficult to study in a controlled, experimental fashion. Here I describe experiments that examined the strength of genetic and cultural (imitative) factors in determining female mate choice in the guppy, Poecilia reticulata. Female guppies from the Paria River in Trinidad have a genetic, heritable preference for the amount of orange body color possessed by males. Female guppies will, however, also copy (imitate) the mate choice of other females in that when two males are matched for orange color, an "observer" female will copy the mate choice of another ("model") female. Three treatments were undertaken in which males differed by an average of 12%, 24%, or 40% of the total orange body color. In all cases, observer females viewed a model female prefer the less colorful male. When males differed by 12% or 24%, observer females preferred the less colorful male and thus copied the mate choice of others, despite a strong heritable preference for orange body color in males. When males differed by 40% orange body color, however, observer females preferred the more colorful male and did not copy the mate choice of the other female. In this system, then, imitation can "override" genetic preferences when the difference between orange body color in males is small or moderate, but genetic factors block out imitation effects when the difference in orange body color in males is large. This experiment provides the first attempt to experimentally examine the relative strength of cultural and genetic preferences for a particular trait and suggests that these two factors moderate one another in shaping social behavior.

Sex proportions of Haemoproteus blood parasites and local mate competition.

Recent genetic evidence suggests that parasitic protozoa often reproduce by "selfing," defined as sexual stages from a single, clonal lineage fertilizing each other. Selfing favors production of an excess of female over male progeny. We tested whether the proportion of male gametocytes of blood parasites of the genus Haemoproteus was affected by variables that could influence the probability of selfing. Proportions of male Haemoproteus gametocytes from 11 passerine host populations were not affected by the age of the parasites' avian hosts, date in season, sex of host, intensity of host's infection, or prevalence of parasites within host populations.

Latitude 19,̊ a romance of the West Indies in the year of Our Lord eighteen hundred and twenty; being a faithful account and true, of the painful adventures of the skipper, the bo's'n, the smith, the mate, and Cynthia;

Mode of access: Internet.

Catálogo del material escolar enviado á la exposición anexa al IIIer Congreso Internacional de Higiene Escolar, Paris, 2-7 de agosto de 1910 con una noticia sobre la instrucción pública primaria. Catalogue de matériel scolaire présenté á l'exposition annexe au IIIe Congres International d'Hygiene Scolaire, Paris, 2-7 aoút 1910, avec une notice sur l'instruction publique primaire.

Mode of access: Internet.

Le maté, au point de vue agricole, médical, hygiénique, militaire et commercial, avec ses modes de préparation.

Mode of access: Internet.

Yerba mate: the tea of South America ...

"Reprinted from the May, 1916, issue of the Bulletin of the Pan American Union, Washington, D.C."