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Phenological aspects of male and female function in hermaphroditic plants

Article Abstract:

The male-female function trade-off in hermaphroditic angiosperms was investigated using a sexual allocation model in which the plant chooses the time in the season in which to allocation to male or female functions. The model was used to study how the timing of investment influences the male-female trade-off. Afterwards, different fitness isoclines for different combinations of male and female input were determined and used to pinpoint what allocation maximizes fitness.

Physiological aspects, Plant physiology, Hermaphroditism, Phenology

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A herbivore paradox: why salt marsh aphids live on poor-quality plants

Article Abstract:

A study of the salt marsh aphid, Uroleucon ambrosiae, living on four types of the host plant, Iva frutescens, reveals a preference of the aphids for short plants that are disturbed physically and physiologically. The presence of the predatory ladybird beetles on taller plants induces the aphids to choose short plants, thereby forcing the aphids to occupy resources of poor quality. The rate of plant population growth is higher in tall plants of good quality.

Analysis, Aphididae, Aphids, Host plants

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Sexual inequalities in helminth infections: a cost of being a male?

Article Abstract:

Analysis of parasitology publications was conducted to determine the relationship between parasite levels and host sex. Factors such as infection resistance and exposure are also considered. Results reveal that male birds and mammals have slightly higher infection levels than females. The bias, however, exists mostly in nematodes parasitizing mammals and may be caused by high testosterone levels which can lead to immunosuppression.

Health aspects, Helminths, Parasitic diseases, Males

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