Competition between female kin for local limiting resources may explain a male-biased secondary sex ratio in the prosimian Galago crassicaudatus. Data demonstrating the skewed sex ratio, a brief summary of field observations on the species, and a simple mathematical statement of the hypothesis are presented. Local resource competition may influence sex ratio in other mammals.

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The shy-bold continuum is recognized as a fundamental axis of behavioral variation in humans, but 3 major issues have not been addressed. First, the taxonomic distribution of shyness and boldness is unknown. Second, the ecological consequences of shyness and boldness have not been studied in natural populations. Third, no one has tried to predict and test patterns of shyness and boldness that might result from natural selection. We show that a shy-bold continuum, which influences diet, predator risk, and parasite fauna, exists in juvenile pumpkinseed sunfish (Lepomis gibbosus). Individual differences are relatively stable in nature but seem to disappear when the fish are held in social and ecological isolation in the laboratory. Thus, phenotypic stability may not reflect innate tendencies to be shy or bold but rather environmental conditions that maintain differences between phenotypically plastic individuals.In humans and at least some other species, individual organisms vary along a behavioral continuum from extreme shyness to extreme boldness (for humans, Kagan, 1991;

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Despite widespread theoretical interest in genetic conflict between parents and offspring, there is little empirical evidence that it exists in nature. Theoretical models suggest two outcomes of conflict not predicted by alternate theories: (1) offspring that control the allocation of parental investment might show escalated demand behaviours (e.g., begging) and demand more resources than they could efficiently use and (2) parents might evolve behavioural counterstrategies which prevented offspring from obtaining extra resources, but which were more costly than a "laissez-faire" parental strategy allowing offspring control. These predictions were tested in budgerigars, (Melopsittacus undulatus) in large flight cages at Davis, California. Budgerigar clutches hatch extremely asynchronously, yet all nestlings grew at similar rates and fledged at similar sizes and ages. This independence of hatch order and performance seemed due primarily to the mother budgerigar's allofeeding strategy: females allofed offspring mainly on the basis of size, and only secondarily attended to begging rate. Offspring of a given age and size were treated the same by their mothers regardless of hatch order, and offspring undersized for their age were fed as if they were younger. In contrast, male budgerigars attended to offspring begging rates. Males tended to initiate feeding bouts when offspring begged, and to allofeed vigorous beggers more often. Variance in male allofeeding behaviour allowed comparisons of size-matched families in which females performed nearly all of the allofeeds to nestlings (= female-fed families) with families in which males and females both allofed nestlings (= male-aided families). The parent controlled the allocation of food in female-fed families, while offspring had greater control over food allocation in male-fed families. As was predicted by conflict theory, the female counterstrategy was effective but potentially costly: the food delivery rate of females was only half as fast as males'. Conversely, offspring control resulted in an escalation of beg rate for the same degree of need (as measured by size and growth), and male-aided offspring obtained nearly three times more regurgitations than female-fed nestlings, yet grew at comparable rates and fledged at comparable sizes and ages. Hence, offspring demanded and obtained more food than they could effectively use. Other avian parents also seem to use effective but potentially costly counterstrategies, and other avian offspring may demand more food than they require. Even if initial hatch asynchronies functioned in brood reduction, the parental strategies described here would allow parents to retain control over the timing and conditions for offspring loss.