The karyotype of the yellow dung fly, Scathophaga stercoraria, a model organism in studies of sexual selection.

Knowledge of karyotypical characteristics of a species is essential for understanding how sexually selected and sexually antagonistic traits evolve. The yellow dung fly Scathophaga stercoraria L. (Diptera: Scathophagidae) is an established model system for studies of sexual selection and sexual conflict, but karyotypical data are lacking to date.

Competitive PCR reveals the complexity of postcopulatory sexual selection in Teleogryllus commodus.

The outcome of mate choice depends on complex interactions between males and females both before and after copulation. Although the competition between males for access to mates and premating choice by females are relatively well understood, the nature of interactions between cryptic female choice and male sperm competition within the female reproductive tract is less clear. Understanding the complexity of postcopulatory sexual selection requires an understanding of how anatomy, physiology and behaviour mediate sperm transfer and storage within multiply mated females.

A cost of cryptic female choice in the yellow dung fly.

Female dung flies Scathophaga stercoraria (L.) store sperm from several males in three or four spermathecae. Selection on the number of spermathecae was successful and the morphological intermediate stages in the evolution from three to four spermathecae are illustrated.

Responses to selection on phenoloxidase activity in yellow dung flies.

Maintaining an immune system is costly. Resource allocation to immunity should therefore trade off against other fitness components. Numerous studies have found phenotypic trade-offs after immune challenge, but few have investigated genetic correlations between immune components and other traits.

Post-copulatory sexual selection and female fitness in Scathophaga stercoraria.

Whether sexual selection increases or decreases female fitness is determined by the occurrence and relative importance of sexual-conflict processes and the ability of females to choose high-quality males. Experimentally enforced polyandry and monogamy have previously been shown to cause rapid evolution in the yellow dung fly Scathophaga stercoraria. Flies from polyandrous lines invested more in reproductive tissue, and this investment influenced paternity in sperm competition, but came at a cost to immune function.

Anthelmintic baiting of foxes against urban contamination with Echinococcus multilocularis.

In recent years, increases in the urban fox population have been observed in many countries of the Northern Hemisphere. As a result, has entered the urban environment. Because of a possible increased risk for alveolar echinococcosis, intervention strategies need to be evaluated.

Maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies.

Direct costs and benefits to females of multiple mating have been shown to have large effects on female fecundity and longevity in several species. However, with the exception of studies examining genetic benefits of polyandry, little attention has been paid to the possible effects on offspring of multiple mating by females. We propose that nongenetic effects of maternal matings on offspring fitness are best viewed in the same context as other maternal phenotype effects on offspring that are well known even in species lacking parental care.

Field experiments on the distributions of eggs of different phosphoglucomutase (PGM) genotypes in the yellow dung fly Scathophaga stercoraria (L.).

Female yellow dung flies can, in the laboratory, influence the probability that stored sperm from different males are used to fertilize eggs. This matches offspring phosphoglucomutase genotypes to the environmental conditions in which the larvae will grow, increasing larval growth success. We conducted field experiments in which dung topology or shading conditions were controlled.

CORRECTING FOR SAMPLING BIAS IN QUANTITATIVE MEASURES OF SELECTION WHEN FITNESS IS DISCRETE.

We show with a simulation that nonrepresentative sampling of two discrete fitness classes leads to biased estimates of selection. Systematic underestimation occurs if the selected class is overrepresented in the sample and overestimation if the unselected class is overrepresented. The bias is greater the stronger the selection intensity, the smaller the true fraction of individuals favored by selected, and the lower the sample size.