The effects of gregarine parasites, body size, and time of day on spermatophore production and sexual selection in field crickets

In laboratory experiments measuring the rate of spermatophore production in the field crickets Gryllus veletis and G. pennsylvanicus by confining single males with a conspecific female, 0–10 spermatophores were produced by each male within 24 h. The number of spermatophores produced was unrelated to a male's body size, but was significantly negatively correlated with the natural levels of gregarines, a protozoan gut parasite, in the males. Spermatophore production in the laboratory peaked between 0600 and 1000 h, as did the proportion of courtship songs given by male crickets in the field, suggesting that mating may occur more frequently in the morning. When single males were placed in jars with two conspecific females, 49% transferred spermatophores to both females, whereas 51% of males only gave spermatophores to one of the females. The results support the hypothesis that parasites are important in sexual selection, and are used to propose a new interpretation of post-copulatory guarding in crickets.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46882/1/265_2004_Article_BF00324437.pd

The use of plant extracts for stored product protection

A wide range of plant extracts have been used alternatively to chemical insecticides against stored product insect pest species. These substances could be used alone or in combination with other alternatives or synthetic insecticides in order to enhance their action. Botanicals can be applied with the same techniques that are used for the application of traditional contact insecticides or fumigants. Given that stored product insects exhibit different levels of sensitivity or tolerance to plant extracts, a wide screening of these substances has been carried out to widen the available tools against these harmful organisms with interesting results. © 2014 Springer India. All rights reserved