Search

Live and dummy stimulus fishes were used to determine why female convict cichlids, Cichlasoma nigrofasciatum, develop orange ventral coloration. Results show that male cichlids are insensitive to ventral color variation, while females seem to use color pattern as a visual cue. Females tend to be aggressive towards brightly colored fishes, while bright females exhibit the least aggression towards an intruding female of intermediate coloration. The findings indicate that sexual dichromatism in C. nigrofasciatum influences intrasexual aggression among females.

Many critical cellular processes, including cell proliferation and tissue repair, exhibit melatonin sensitivity. We examined the effects of exogenous melatonin, photoperiod and temperature on regeneration in Phagocata gracilis, a common North American turbellarian. Planarian regeneration involves the proliferation and migration of pluripotent stem cells capable of replacing missing body components. A characteristic mass of cells (blastema) forms during planarian regeneration, and its formation, growth and differentiation provide reliable endpoints for the study of regenerative processes. We tested the effects of exogenous melatonin at two concentrations and three photoperiods on both head and tail regenerates under seasonal diurnal temperature regimes. High temperatures and melatonin treatment increased mortality in P. gracilis, and surviving melatonin-treated subjects exhibited delayed regeneration. Asymmetrical and deficient regeneration was more common in melatonin-treated, high temperature and dark treated subjects. Additionally, high temperature and melatonin induced a novel locomotor dysfunction. [ABSTRACT FROM AUTHOR]

This case study examines differences between how the animal-behavior-research fields of ethology and sociobiology account for female ornamental traits. I address three questions: 1) Why were female traits noted in early animal-behavior writings but not systematically studied like male traits? 2) Why did ethology attend to female signals before sexual-selection studies did? 3) And why didn't sexual-selection researchers cite the earlier ethological literature when they began studying female traits? To answer these questions, I turn to feminist and other science-studies scholars and philosophers of science. My main framework is provided by Bruno Latour, whose model I position within relevant feminist critique (Latour ). This approach provides an interactive account of how scientific knowledge develops. I argue that this embedded approach provides a more compelling reading of the relationship between gender and science than does focusing on androcentric biases. My overall aim is to counter arguments by some feminist biologists that feminist tools should emphasize the correction and removal of biases, and to address their fears that more rigorous critiques would lead to relativism or otherwise remove science as a tool for feminist use. [ABSTRACT FROM AUTHOR]