Changes in Haemoproteus sex ratios: fertility insurance or differential sex lifespan?

Abstract:

There is little direct evidence of the fitness effects of changes in malaria gametocyte sex ratio. Gametocyte sex ratios in haemospororin parasites (phylum Apicomplexa) are usually female skewed. However, in some cases and especially in Haemoproteus parasites, less female–biased and even male–biased sex ratios are encountered. The ‘fertility insurance hypothesi’ tries to explain these biases as an evolutionary strategy to facilitate gamete encounter. Thus, the hypothesis pbkp_redicts that, if there is a reduction in gametocyte density (intensity of infection) or other factors preventing gametes from meeting, a change to a higher proportion of male gametocytes may be favoured. By contrast, a change in sex ratio may be caused by other non–adaptive mechanisms, for example differential survival of the gametocytes of each sex. We study within–host changes in Haemoproteus majoris sex ratios following an experimental …

Año de publicación:

2004

Keywords:

Fuente:

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