A metagenome wide association (MGWA) study of bacterial host association determinants in Drosophila predicted that LPS biosynthesis genes are significantly associated with host colonization. We were unable to create site-directed mutants for each of the predicted genes in Acetobacter, so we created an arrayed transposon insertion library using Acetobacter fabarum DsW_054 isolated from Drosophil...

the black bean aphid, aphis fabae scopoli, is a major pest of broad bean, vicia faba l. and sugar beet, beta vulgaris l., the most abundant parasitoid of a. fabae in agroecosystems is lysiphlebus fabarum (marshall), a multivoltine species with mainly thelytokous reproduction in central europe. since l. fabarum females mimic ants to obtain honeydew directly from aphids it was reasoned that a fem...

The presence of nonprey or nonhosts is known to reduce the strength of consumer- resource interactions by increasing the consumer's effort needed to find its resource. These interference effects can have a stabilizing effect on consumer-resource dynamics, but have also been invoked to explain parasitoid extinctions. To understand how nonhosts affect parasitoids, we manipulated the density and d...

Antagonistic coevolution between hosts and parasites can result in negative frequency-dependent selection and may thus be an important mechanism maintaining genetic variation in populations. Negative frequency-dependence emerges readily if interactions between hosts and parasites are genotypespecific such that no host genotype is most resistant to all parasite genotypes, and no parasite genotyp...

The aphid parasitoid Lysiphlebus fabarum is suspected to form distinct, host-associated lineages and exhibits poorly understood variation in reproductive mode including thelytokous and arrhenotokous populations. As a tool to study these issues, we developed 11 polymorphic microsatellite markers. The observed number of alleles ranged from two to 35, and the observed heterozygosity ranged from 0....