Do Wolbachia-associated incompatibilities promote polyandry?

The genetic incompatibility avoidance hypothesis as an explanation for the polyandrous mating strategies (mating with more than one male) of females of many species has received significant attention in recent years. It has received support from both empirical studies and a meta-analysis, which concludes that polyandrous females enjoy increased reproductive success through improved offspring viability relative to monandrous females. In this study we investigate whether polyandrous female Drosophila simulans improve their fitness relative to monandrous females in the face of severe Wolbachia-associated reproductive incompatibilities.

Sexual selection: signals to die for.

Sexual signals are conspicuous and are typically assumed to be energetically costly, which keeps them honest. A recent study on fireflies has found that signal production is energetically cheap, but signalling remains expensive because of eavesdropping predators.

Mating behaviour: promiscuous mothers have healthier young.

A small marsupial has thrown new light on the question of why females typically mate with several males: promiscuous female antechinuses have many more surviving offspring because males that are successful in sperm competition also sire healthy offspring.

Wolbachia infection reduces sperm competitive ability in an insect.

The maternally inherited bacterium Wolbachia pipientis imposes significant fitness costs on its hosts. One such cost is decreased sperm production resulting in reduced fertility of male Drosophila simulans infected with cytoplasmic incompatibility (CI) inducing Wolbachia. We tested the hypothesis that Wolbachia infection affects sperm competitive ability and found that Wolbachia infection is indeed associated with reduced success in sperm competition in non-virgin males.

Association of benzodiazepine injection with the prescription of temazepam capsules.

Temazepam capsules have become a popular choice for benzodiazepine injection by injecting drug users, and serious vascular and tissue damage leading to ulcers and gangrene can result. We compared the self-reported benzodiazepine injecting behaviour of 91 heroin users with their Pharmaceutical Benefits Schedule (PBS) records for the preceding 5 years. We found that individuals prescribed PBS temazepam capsules were more likely to report injecting benzodiazepines than individuals who had either not been prescribed PBS temazepam capsules or had been prescribed PBS temazepam tablets.