Understanding the factors that determine how species respond to threats such as climate change and habitat loss is crucial in predicting future trends and also in management of threatened species and habitats. Two potentially important factors in determining animal population abundance and resilience are the degree of (1) polyandry and (2) the size of the genome, but to date there have been virtually no tests of their effects. We propose to address these knowledge gaps using the British Lepidoptera (butterflies and moths) using several long-term monitoring schemes for these animals which have already been used to identify population trends for a large number of species1. This project will gather further data on British moths via a trapping programme plus a citizen science approach with amateur moth trappers contributing specimens, allowing the role of both these factors to be assessed with large, long-term datasets on each species.
In recent years it has become clear that strong precopulatory sexual selection, via female choice or intrasexual contests, can enhance adaptation rates and allow ‘evolutionary rescue’ when a population is faced with a changing environment2–4. There is, however, some evidence that postcopulatory sexual selection might have the opposite effect—ostracod species with larger sperm pumps are more likely to go extinct over geological time5 and dung beetle species with relatively large testes have reduced abundance in disturbed environments2. Whether this is a general effect is currently completely unknown. We will assess the degree of polyandry for a range of moth species by counting the spermatophores present in the reproductive tracts of freshly caught specimens — unlike other insect taxa the spermatophore membranes do not break down in the Lepidoptera6— and also by measuring relative testes size which is strongly correlated with the intensity of sperm competition7.
Recent research has found that genome size is an important determinant of many aspects of plant ecology, such as growth rate and the response to nutrient levels8,9. These effects are thought to arise because genome size impacts minimal cell size, which in turn influences for example water loss, carbon dioxide assimilation, cell storage and cell wall strength10. In animals too, genome size influences their biology. There is evidence, for example, that genome size influences larval development and life history traits in frogs11 and it is correlated with reproductive success in seed beetles12. In addition, genome size is thought to be reduced in birds to facilitate flight13 and it impacts growth rate under limiting nutrients in freshwater snails14. Indeed, building and maintaining cells with large genomes may be more nutrient demanding than smaller ones, because nucleic acids are so rich in nitrogen and phosphorus. It is perhaps for this reason that genome size might impact food quality and feeding preferences15, perhaps because of the nutritional value of nucleic acids.
Furthermore, genome size may impact the production of anucleic sperm used in polyandrous moth species to pug the female reproductive tracks after mating and reduce the success of competing males. Potentially there might be selection for individuals to produce more anucleic sperm if they have a large genomes. Lepidopteran genome sizes vary nearly 10-fold (range from 0.215 Gb/1C to 1.897 Gb/1C) and we anticipate that across this range there will be effects on the biology of the insects. We will use existing data (e.g. from the Darwin Tree of Life project and the animal genome size database) and supplement this with measurements of genome sizes of other species. Host plant genome sizes are available on the Kew Plant DNA C-values database. Using these data we will will test the hypotheses that Lepidopteran genome size impacts growth rate, sexual system (polyandry), generation times and host range of the plants (see16 for a preliminary test of the last)
The long-term Lepidoteran data sets to be used will be the Rothamsted Insect Survey and the National Moth Recording Scheme. These datasets will give a combination of time-series data at specific locations (RIS) and occupancy data (NMRS, National Moth Recording Scheme) allowing us to develop statistical models to test the effects of polyandry and genome size on a suite of important aspects of the ecology of these animals. These results will provide a uniquely detailed assessment of these important questions with considerable potential for high-impact publications.
You should normally have, or expect to obtain, at least 2:1 Honours degree (or international equivalent) in a related subject.
Eligibility and How to Apply
See our How to Apply page.
The NERC Panorama DTP are hosting ‘Demystifying the PhD application process’ webinars on the 9th and 12th December – sign up now!
The minimum English language entry requirement for postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.
Webinar recording
For more information on specific projects, why not watch a recording of the webinar we held on 29 November? You will be able to hear presentations on each of the projects, as well as on overview of the Panorama DTP and the question and answer session that followed the presentations.
Equal Opportunities:
Within the NERC Panorama DTP, we are dedicated to diversifying our community. As part of our ongoing work to improve Equality, Diversity and Inclusion within our PhD funding programme, we particularly encourage applications from the following identified underrepresented groups: UK Black, Asian and minority ethnic communities, those from a disadvantaged socio-economic background, and disabled people. To support candidates from these groups, we are ringfencing interviews, providing 1-2-1 support from our EDI Officer (contact Dr. Katya Moncrieff) and hosting a bespoke webinar to demystify the application process. Candidates will always be selected based on merit and ability within an inclusive and fair recruitment process.
Continue with Facebook
