Dominance,Coloration, and Social and Sexual Behavior in Male Drills <Emphasis Type="Italic">Mandrillus leucophaeus</Emphasis>

Sexual selection has driven the evolution and elaboration of a wide variety of displays and ornaments in male nonhuman primates, including capes, cheek flanges, and sexual coloration. Among the most sexually dimorphic of all primates is the drill (Mandrillus leucophaeus), the males of which can be 3 times the mass of females, possess large canines, and exhibit extremely bright sexual skin coloration. However, the function of male coloration in this species has never been examined. Here, we present data on male color (measured objectively using digital photography), dominance rank, measures of male-female association, and key sexual behaviors, of adult male drills (n = 17) living in four semi free-ranging enclosures at the Drill Rehabilitation and Breeding Center in Nigeria. We test the hypothesis that male coloration is a badge of status, indicating dominance rank, and the hypothesis that male coloration attracts females. We found that male coloration did indicate rank, and that high ranking, strongly colored males were more likely to associate with adult females, and more specifically with fully tumescent females. These males also engaged in more sexual activity. However, measures of male-female association and sexual behaviors were not related to male color once rank had been taken into consideration; i.e., for males of a given rank, females did not prefer those that were more colorful. We discuss the results in light of what is known about the wild drill social system, in which unfamiliar individuals may come together in “supergroups,” and in which quality indicators of competitive ability may be particularly important.     

Paleoecological reconstruction of changes in the productivity of a small,meromictic lake in Southern Ontario,Canada

Some aspects of the paleoproductivity of meromictic Crawford Lake, near Toronto, are inferred from a study of its sedimentary pigments, and diatoms. Several stages of lake development are observed over the 35 cm-deep sediment core removed from the center of Crawford Lake. Evidence of changes in lake productivity during the last 300 years was reflected by significant stratigraphic sediment pigment changes which were associated with European settlement in the Crawford Lake watershed and recent alterations associated with the area's operation by the Conservation Authority (1969 — present). One of the most important factors correlated with paleoproductivity was land clearance (mainly logging of white oak and pine). Deforestation during the last century is correlated with an increase in the amount of algal pigments deposited in the lake's sediments during the 1800's. During the last 10 years a striking increase in the accumulation of chlorophyll derivatives was observed. This is correlated with a dramatic increase in the number of visitors to the lake.Stratigraphic changes in the ratio of cyanobacterial to phototrophic bacterial pigment accumulation are used to infer changes which occurred during the shift from mesotrophy to eutrophy in Crawford Lake.     

Sex ratio and intrasexual kin competition in mammals

Summary Asymmetries in both intrasexual competition and generation overlap occur in Antechinus (Dasyuridae; Marsupialia). We show that the range of interpopulation variation in the sex ratio of pouch young spans and exceeds the range of sex ratios at birth hitherto recorded from eutherians (Clutton-Brock and Albon 1983). Although postweaning dispersal and male mortality are similar among all Antechinus populations, interpopulation variance in female longevity leads to variable duration of mother/daughter interaction. As this duration increases, parental investment is increasingly biased toward males, supporting the view that local competition among female kin for resources may influence mammalian sex ratios.     

Application of response surface methodology to optimization of the fixation of ribonuclease a on glutaraldehyde activated amine silica

Summary We have used response surface methodology to study the interactions between various parameters (pH, temperature, enzyme concentration) controlling the immobilization of ribonuclease A on to glutaraldehyde activated-amine Spherosil beads. The optimum activity of immobilized ribonuclease A was observed at pH=9.1. The specific activity of the immobilized enzyme was affected by the pH and by the enzyme concentration.     

Isolation, characterization, and expression of a second beta-tubulin-encoding gene from Colletotrichum gloeosporioides f. sp. aeschynomene.

Colletotrichum gloeosporioides f. sp. aeschynomene is a fungal plant pathogen of Aeschynomene virginica. A beta-tubulin-encoding gene (TUB2) from this pathogen was cloned and sequenced. The deduced amino acid sequence of TUB2 had a high degree of homology to other fungal beta-tubulins. A portion of TUB2 from a benomyl-resistant C. gloeosporioides f. sp. aeschynomene mutant was also cloned and sequenced. A point mutation resulting in a glutamic acid-to-lysine substitution at amino acid 198 likely confers benomyl resistance. The mutation is relevant for use as a selectable marker in developing a gene transfer system in C. gloeosporioides f. sp. aeschynomene. Northern (RNA) hybridizations with C. gloeosporioides f. sp. aeschynomene TUB2 and another C. gloeosporioides f. sp. aeschynomene beta-tubulin-encoding gene (TUB1) as probes showed differential expression of these genes in different cell types.     

Influence of growth rate on pigment and lipid composition of the microalgaIsochrysis aff.galbana clone T.iso

A continuous culture ofIsochrysis aff.galbana clone T.iso, used to feedPecten maximus larvae at IFREMER (Brest, France), was carried out in a chemostat at its optimum temperature for growth (26 °C). Changes in pigments, lipid class (neutral, glyco- and phospholipids) and degree of fatty acid unsaturation were studied at three different growth rates (0.33, 0.5, 1 d^–1). As predicted by chemostat theory, a slow growth rate produced higher cell numbers and higher biomass per unit volume. These cells were low in chlorophylla and carotenoids, but rich in neutral lipids. In contrast, cultures with a fast growth rate yielded lower cell concentrations, buth higher chlorophylla, carotenoid and membrane lipid contents per cell. Changes in polyunsaturated fatty acid distribution were related to differences in algal growth rates. Neutral lipids contained mainly saturated and monounsaturated fatty acids (C18:19) at low growth rates whereas they were enriched in polyunsaturated fatty acids, especially C22:63, at high growth rates. Therefore, it is suggested that the growth rate in continuous cultures be controlled so as to adjust the relative proportions of polyunsaturated fatty acids in lipid classes of the diet meant for larval nutrition.Author for correspondence