Research
Interests
Insects play a vital role in our ecosystems, yet they can transmit diseases and inflict significant damage on agriculture and horticulture. It is crucial to manage 'pest' insects effectively while preserving 'beneficial' insects. Presently, insecticides are the main method for pest control, but they pose risks to human health and the environment and often lead to resistance. The Sterile Insect Technique (SIT) offers an environmentally friendly, safe, and species-specific alternative, suitable for integration into area-wide integrated pest management programs (AW-IPM). Traditional SIT involves releasing large numbers of sterilized males, produced in specialized facilities and made infertile through ionizing radiation, into infested areas. These males cannot produce offspring, leading to a gradual decline in the wild population. Key to SIT's success are strategies like sex separation in rearing facilities for male-only releases and ensuring male sterility.
Recent genetic advancements provide new avenues for enhancing SIT or other eco-friendly pest control methods for various insect pests. We are rigorously evaluating genetically modified strains, such as genetic sexing strains (GSS) and male-sterility strains, for potential use in integrated pest control programs, alongside other technologies. To enhance the safety and comparative analysis of transgenic systems, we are developing control strains and technologies for stabilizing and assessing the risks of transgenic insects. This involves impartial comparisons of genetically modified organisms (GMOs), conventional genetic strains, and emerging non-transgenic and non-GM strains and technologies.
Keywords: Environmentally friendly insect pest population control; Sterile insect technique (SIT), incl. genetic sexing strains (GSS); Risk assessment of transgenic insects; Evaluation of transgenic technologies for agricultural pests and mosquitoes; Development of molecular biological systems for transgene stabilization; Molecular biocontrol; CRISPR-Cas Gene Editing technologies; non-GM technologies
Projects
2022-ongoing, EU HORIZON Europe-RIA, Coordinator: Marc F. Schetelig
Read more about the project and follow us on:
REACT_insect on Linkedin | REACT homepage | IPCL Newsletter
Developing transgene-free CRISPR-based genetic sexing systems for insect pest control
2021-ongoing, DFG Research Grant to M.F. Schetelig and P. Papathanos
Together with Professor Philippos Papathanos from Israel, we aim to develop transgene-free genetic sexing systems for Ceratitis capitata and Aedes albopictus. This involves identifying a temperature-sensitive marker gene and modifying it for sex-specific expression. This approach facilitates selective breeding and release of one gender, typically males, to control pest populations. By utilizing temperature sensitivity, we ensure the lethal gene is activated only under certain conditions, offering a targeted and environmentally friendly solution for pest management.
Development of conditional CRISPR systems for functional genomics and pest control of insects
2021-ongoing, DFG Research Grant to Y. Yan
Drosophila melanogaster serves as an ideal model for functional genomics, yet maintaining strains with certain mutations is challenging due to lethal or sterile phenotypes. This proposal introduces a novel conditional CRISPR-based Sterile Insect Technique (ccSIT), utilizing heat induction and the Tet-Off system to control Cas9 expression. This allows breeding under specific conditions, with a shift to restrictive conditions producing only sterile males. Applied in Sterile Insect Technique programs, this approach also aids functional genomic studies, exemplified using the Spotted Wing Drosophila (Drosophila suzukii), a significant global pest.
Generic approach for the development of genetic sexing strains for SIT applications
2019-2025, Coordinated Research Project of the International Atomic Energy Agency
The goal of this Coordinated Research Project (CRP) is to create generic approaches for developing Genetic Sexing Strains (GSS). CRPs provide a valuable platform for global collaboration among scientists. This particular CRP unites 22 research contract and agreement holders, along with 32 observers from countries including Argentina, Australia, Canada, China, Germany, Israel, Italy, Mexico, South Africa, the UK, and the USA, all focused on advancing GSS for Sterile Insect Technique (SIT) applications. Regular meetings facilitate discussion and progress updates among participants.
Learn more about this CRP and our contributions in Gießen:
CRP Report | IPCL Newsletter, page 15
Organisms
Ceratitis capitata (Diptera: Tephritidae)
Ceratitis capitata, commonly known as the Mediterranean fruit fly or Medfly (German: Mittelmeerfruchtfliege), ranks among the world's most economically significant pests. Belonging to the Tephritidae family, this "true fruit fly" can infest over 200 types of fruits, vegetables, and nuts, including oranges, grapefruits, mangoes, guavas, plums, pears, and coffee. Female Medflies lay their eggs beneath the skin of ripening fruit. The larvae then reside within the fruit, feeding on its flesh, and causing extensive damage that amounts to billions of dollars in agricultural and horticultural losses globally. The Sterile Insect Technique (SIT) has been effectively employed to control Medfly populations, either by suppression, containment, prevention, or local eradication. Consequently, the Medfly is a prominent subject in SIT research due to its impact and the successful application of this control method.
In our research, we maintain approximately 20 distinct strains of Ceratitis capitata (Medfly) in our laboratories. This collection includes wild-type strains from various locations, natural mutants, and transgenic and genetically modified strains. Medflies thrive at warm temperatures, ideally around 25°C. Controlled environments enable us to effectively study and understand the various aspects of Medfly biology and behavior.
Drosophila suzukii
Drosophila suzukii, commonly known as the Spotted Wing Drosophila (SWD) or Cherry Vinegar Fly (German: Kirschessigfliege), is a significant pest affecting fruit crops and poses a substantial economic threat to soft-skinned fruits such as cherries, blueberries, raspberries, blackberries, and grapes. Unlike Drosophila melanogaster, SWD targets ripening fruits rather than decaying ones. Males are identifiable by distinct dark spots near their wingtips. Originally from East Asia, SWD has since spread to America and Europe. Effective and sustainable control methods are still lacking; current measures include traps, nets, parasitoids, and limited use of insecticides due to the timing of infestation close to harvest. Research is ongoing to explore gene editing for population control, but Sterile Insect Technique (SIT) is not yet established for SWD.
In our research, we culture various SWD strains, including wild type strains from different origins and genetically modified variants. We also maintain D. melanogaster cultures. All life stages of SWD are kept in vials at about 25°C, with a jellylike food mixture containing ingredients such as flour, malt, and molasses for the larvae, and yeast for the adults. This controlled environment enables comprehensive study and experimentation with these species.
Mosquitoes
Aedes aegypti, also known as the Yellow Fever Mosquito (German: Gelbfiebermücke oder Tigermücke), is responsible for approximately 200,000 Yellow Fever and 390 Mio Dengue cases leading to 30,000 and 36,000 deaths annually, respectively. It also transmits diseases such as Chikungunya and Zika. It's important to note that only female mosquitoes transmit these diseases, requiring blood for egg production. In contrast, males, which feed on sugar sources, are not involved in disease transmission. Control methods for the Yellow Fever Mosquito include using insecticides, infection with the bacterium Wolbachia, genetic modification, and the Sterile Insect Technique (SIT), currently in pilot testing phases.
In our research, we culture various strains of Aedes aegypti, encompassing wild-type strains from diverse locations, natural mutants, and genetically modified varieties. The species prefers warm and humid conditions. Adults are housed in large cages, with males fed sugar and females provided blood meals. Larvae and pupae are reared in water trays, simulating their natural breeding environment. This controlled rearing approach facilitates our in-depth study and development of novel control strategies for this mosquito species.
