Organisms that inhabit the surface of the Earth have evolved an endogenous 24 hour clock that infiltrates every level of biological organisation from the molecular to the ecological. This biological timer is a critical adaptation to living on a rotating planet with predictable daily and seasonal cycles of light and dark, warmth and cold. The fruitfly Drosophila melanogaster has provided the model system by which the highly conserved genetic and molecular basis of animal rhythmicity was initially dissected, winning a Nobel Prize in 2017 to its discoverers. Our network INCITE (INsect Clock Initial Training Experience) will provide state-of-the-art doctoral training to doctoral candidates in insect molecular chronobiology using a comparative approach in which the circadian clock will be studied from a variety of perspectives. These will include the recruitment of the clock for i) insect seasonal ‘hibernation’ or diapause, a critical life-history feature that has important implications for range expansion under global warming, ii) in pollination, ii) in pest control, iv) in optimising the development of insects mass-reared as a protein source for human/animal consumption – a sustainable model for agriculture and vi) in fundamental circadian biology of the model insect, D. melanogaster. In addition to their research projects, doctoral candidates will be seconded to partners both academic and industrial within the network and be further exposed to a variety of successful well-defined and time-tested courses that supplement those already offered at their local institutions, and will enhance and develop their scientific, entrepreneurial and transferable skills. INCITE will generate highly-trained, mobile and employable graduates that will be welcomed both in academia and industry. These two advertised positions at the University of Groningen are part of a total of 17 PhD positions that available at European partner institutes within this Marie Sklodowska-Curie Doctoral Network.

Project 1 Improving mass rearing of houseflies by optimizing the circadian environment
The project aims to obtain fundamental knowledge on house fly circadian organisation and photoperiodism and exploit their influence on growth and reproduction to optimize mass rearing. The black soldier fly (H. illucens) and housefly (M. domestica) are being developed as protein sources for feed and food. Growth and reproduction in insects are regulated by photoperiod and temperature and responses to these environmental variables is under the control of the circadian system. By altering light and temperature regimes and tuning them for optimal growth, substantial economic benefit may be gained. This requires knowledge of the circadian system of the housefly and understanding of the influence of daylength and light conditions on its growth and reproduction. Locomotor activity is a read out for circadian behaviour and requires knowledge of the underlying molecular regulation of clock genes. Social context, such as population density and sex ratio can also affect activity patterns. There is a need to study how temperature and light regimes affect activity patterns, reproduction and growth under mass rearing conditions. In addition, selection lines of houseflies are currently being generated for commercial use that can grow efficiently on particular kinds of waste streams that are, for example, rich in starch or sugar. Such selection for nutrient conversion can affect gene expression and physiology/metabolism of flies, which in turn will affect behaviour. The interaction between food composition and the circadian clock will also be investigated in the mass rearing context. We will first establish basic properties of circadian light entrainment and temperature effects on life history of larval and adult houseflies. We will measure circadian clock gene transcription in response to light and temperature stimulation as well as diet in larvae and adults. We will test whether shortened or lengthened light-dark cycles, particular light wavelengths, and constant light affect larval growth, to find the optimal combination of temperature and photoperiod for mass rearing. Finally, as flies of different geographical origin may be adapted to local photoperiodic conditions we will investigate responses of populations from various latitudes.

Supervisors:

Prof. Leo W. Beukeboom, l.w.beukeboom@rug.nl
Prof. Jean-Christophe Billeter, j.c.billeter@rug.nl
Prof. Bregje Wertheim b.wertheim@rug.nl

Project 2 Photoperiodism: circadian photoreception driving body composition changes in migratory Lepidoptera
To investigate the circadian and photoperiodic inputs in migratory Lepidoptera. Migratory animals typically undergo dramatic changes in body composition before migration. In multivoltine butterflies and moths, these changes occur in the generations that prepare for migration and typically encompass increase in fat body size and thoracic flight muscles. Such annual changes in behaviour and body composition are seasonally synchronized by photoperiod. The photoreceptive pathway and the role of the circadian system are only partly described in the diurnal migratory Monarch butterfly, but are lacking in nocturnal moths. In this project we will describe the photoreceptor system involved in the photoperiodic response in diurnal and nocturnal Lepidoptera at different life stages, such that spectral composition of light can be optimized to induce changes in body composition. Sensitivity in photoperiod response mechanisms will be described by comparing a nocturnal moth and diurnal butterfly. Autographa gamma (moth) and Pieris brassicae (butterfly) are the first choice since they can be easily raised on cabbage and are both multivoltine migratory species. Photoperiod sensitive life cycle stages will be established and will be subsequently used to establish spectral sensitivity of the photoperiodic response leading to adaptive changes in body composition. The circadian involvement in the photoperiodic body composition response will be established by knockdown or CRISPR-Cas9 genetic manipulation.

Supervisors:

Prof. Roelof Hut, r.a.hut@rug.nl
Prof. Casper van der Kooi, c.j.van.der.kooi@rug.nl

Additional information
https://research.rug.nl/en/organisations/beukeboom-lab-evolutionary-genetics
https://research.rug.nl/en/persons/jean-christophe-billeter
https://research.rug.nl/en/organisations/hut-lab-chronobiology
https://research.rug.nl/en/organisations/van-der-kooi-lab-evolutionary-biophysics

Organisation
Founded in 1614, the University of Groningen enjoys an international reputation as a dynamic and innovative institution of higher education offering high-quality teaching and research. Flexible study programmes and academic career opportunities in a wide variety of disciplines encourage the 34,000 students and researchers alike to develop their own individual talents. As one of the best research universities in Europe, the University of Groningen has joined forces with other top universities and networks worldwide to become a truly global centre of knowledge.

The PhD is expected to contribute to the organization of the project in terms of collecting research data, participation in consortium meetings, and to the analysis and writing of the shared output. The candidate will be based in the research groups of Profs. J-C. Billeter and L.W. Beukeboom (project 1) and Profs. R.A. Hut and C.J. van der Kooi (project 2) at the University of Groningen. Project 1 is co-supervised with Prof. B. Wertheim (Wageningen University) and Prof. J. Terblanche (Stellenbosch University). For project 1 the candidate is expected to spend a period in Stellenbosch, South Africa, to cooperate and develop the research with the connected research group (Prof. Terblanche).

The successful candidate should have

- A Master degree (or equivalent) in chronobiology, entomology or a related field.
- High motivation in pursuing academic research.
- High and demonstrated English proficiency.
- Effective communication (both written and spoken in English) and collaboration abilities.
- Willingness to travel abroad, perform secondments in partner groups and attend network meetings.
- For project no. 1 spend a period in Stellenbosch, South Africa.
- Demonstrable time management skills.

Fixed-term contract: 42 months.

We offer you, following the Collective Labour Agreement for Dutch Universities:

- A salary of € 2,872 gross per month in the first year, up to a maximum of € 3,670 gross per month in the fourth and final year for a full-time working week.
- A holiday allowance of 8% gross annual income and an 8.3% year-end bonus.
- A full-time position (1.0 FTE) for 42 months (3.5 years). The successful candidate will first be offered a temporary position of one year with the option of renewal for another 2.5 years.
- Prolongation of the contract is contingent on sufficient progress in the first year to indicate that a successful completion of the PhD thesis within the next 2.5 years is to be expected.
- A PhD training programme is part of the agreement and the successful candidate will be enrolled in the Graduate School of Science and Engineering.
- For project 1 a double degree from the Universities of Stellenbosch and Groningen.
- An international training programme in a Marie Sklodowska-Curie Doctoral Network funded programme with regular network meetings.

The applicant must not have resided for more than 12 months in the last 3 years prior to the singing her/his contract in the country of the host institute.