Acquisition, persistence, and loss of reproductive symbionts
Heritable bacterial symbionts are an important component of arthropod ecology and evolution. Many of these symbionts are maternally transmitted, following an ovarial transmission route. Maternally transmitted symbionts can spread rapidly within arthropod populations by inducing various reproductive phenotypes. These phenotypes include: cytoplasmic incompatibility, parthenogenesis, and sex allocation distortion. We use a diversity of entomological systems to dissect the traits that shape the acquisition, persistence, and loss of (endo)symbiotic infection in arthropods. Our model systems include rove beetles, ants, leaf-mining flies, and spider mites (we love arthropods). Across these divergent systems, we unravel the mechanisms and efficiency of maternal transmission. We study the mechanistic basis of symbiont-mediated phenotypes from the perspective of host and symbiont. Our work also contributes to the development of effective and stable CI-based pest management.
Post-zygotic isolation (hybrid dysfunction)
Incompatible matings can result in dysfunctional hybrid offspring that suffers from various fitness penalties, including sterility and inviability. Hybrid dysfunction is a strong isolating barrier that drives speciation and maintains species barriers and its proximate basis has captivated evolutionary biologists since the early 20th century. The complex Tetranychus genus consists of cryptic species groups that are typified by widespread nuclear and mito-nuclear incompatibilities that cause multiple hybrid defects. We focus on characterizing the molecular-genetic mechanisms of conspecific and heterospecific hybrid dysfunction and identifying the causal incompatibility alleles.
Herbivory
Herbivory, or feeding on non-decayed plant material, has only evolved in approximately one third of all animal species. Plant feeding imposes major nutritional challenges to animals. Plant tissues are typically nutritionally imbalanced and contain complex phytochemicals, recalcitrant to enzymatic digestion. In addition, in response to feeding, plants have developed many chemical defense mechanisms to protect themselves. To counter these chemical defences, arthropods in turn develop an arsenal of enzymatic mechanisms. Multiple feeding guilds have evolved in herbivorous arthropods, including leaf-mining and cell-content feeding. Here, we can distinguish two research lines: host plant range evolution and phytochemical detoxification.
In our lab, we focus on cyanogenesis, a common plant defence mechanism that releases toxic cyanide upon herbivore feeding. We are currently tracking how herbivorous arthropods adapted to the varying levels of plant-produced cyanide. Here, we combine field entomology with population and molecular biology, using a wide range of arthopod model systems (such as mealybugs, spider mites, caterpillars, and sawflies).
Agromyzid leaf-mining flies are amazing. Within Liriomyza, we observe a dynamic host plant range, with specialists and generalists embedded within single species groups. We study genome evolution in this speciose cosmopolitan genus that is prone to hybridize.
