BACKGROUND When some combinations of maternal and paternal alleles have a detrimental effect on offspring fitness, females should be able to choose mates on the basis of their genetic compatibility. In numerous Hymenoptera, the sex of an individual depends of the allelic combination at a specific locus (single-locus Complementary Sex Determination), and in most of these species individuals that...

In the endoparasitic wasp Venturia canescens (Hymenoptera: Ichneumonidae) two genetically distinct lines, which differ at the VLP1 gene locus, appear to coexist sympatrically in thelytokous as well as arrhenotokous field and laboratory strains. Both lines display quite distinct morphological, physiological and behavioural variations, such as different oviposition strategies, egg numbers and gro...

Insects are subject to attack from a range of natural enemies. Many natural enemies, such as parasitoids, do not immediately, or ever, kill their victims but they are nevertheless important in structuring biological communities. The lag that often occurs between attack and host death results in mixed populations of healthy and parasitised hosts. However, little is understood about how the effec...

Differences in learning and memory dynamics between populations are suspected to result from differences in ecological constraints such as resource distribution. The two reproductive modes (strains) of the parasitoid wasp Venturia canescens share the same geographical areas but live in contrasting habitats: arrhenotokous wasps live in the wild (generally orchards), whereas thelytokous ones live...

Inbreeding and inbreeding depression are key processes in small or isolated populations and are therefore central concerns for the management of threatened or (re)introduced organisms. Haplodiploid species of the order Hymenoptera have a particular status with regard to inbreeding depression. Although recessive deleterious alleles that are expressed in males should be purged, an alternative for...

The interference ideal free distribution (IFD) model of Sutherland makes a number of predictions that have yet to be tested and that have implications for the validity of subsequent extensions to the theory. We tested these predictions in a study using different densities of the parasitoid wasp, Venturia canescens, foraging on patches containing different densities of its host, Plodia interpunc...

BACKGROUND Coexistence of sexual and asexual populations remains a key question in evolutionary ecology. We address the question how an asexual and a sexual form of the parasitoid Venturia canescens can coexist in southern Europe. We test the hypothesis that both forms are adapted to different habitats within their area of distribution. Sexuals inhabit natural environments that are highly unpre...

Atriplex canescens (fourwing saltbush) is a C4 perennial fodder shrub with excellent resistance to salinity. However, the mechanisms underlying the salt tolerance in A. canescens are poorly understood. In this study, 5-weeks-old A. canescens seedlings were treated with various concentrations of external NaCl (0-400 mM). The results showed that the growth of A. canescens seedlings was significan...