Aphid ecology and population dynamics

Lead Research Organisation: Rothamsted Research
Department Name: Unlisted

Abstract

Many insects are pests of agriculture, horticulture and forestry and vectors of plant, animal and human diseases. Many others are beneficial, contributing to ecosystem services such as pollination, biological control and enjoyment of the countryside. The long-term datasets from the Rothamsted Insect Survey suction and light trap networks provide unmatched opportunities for investigating impacts of climatic change on the phenology, abundance and distribution of a range of species.

Objectives:
The objectives of this project are to investigate and predict the impacts of climate change on the dynamics of pest and beneficial insects within the wider framework of predicting climate change impacts on agricultural systems.

Methods
Data from the suction and light trap networks will form the basis of this project. Correlative analyses examining relationships between aspects of population dynamics (phenology, abundance, distribution) of a range of insect taxa, and both exogenous drivers (especially climate) and endogenous drivers (e.g. Density dependent feedback mechanisms) will be undertaken. Responses of different groups will be compared and a traits-based approach used to examine the transferability of results between taxa and to predict the results for taxa not specifically examined. Climate change scenarios will be substituted into resulting models and predictions of insect dynamics made on the basis of such scenarios. Hypotheses will be generated to explain the mechanisms behind observed relationships between datasets, and these hypotheses will be tested.

Publications

10 25 50
 
Description Climate is important in synchronising population dynamics of aphids over large scales.
Many pest insects are becoming increasingly abundant in a changing climate whilst many insects of conservation concern are becoming rarer. This is thought to be because the traits leading to pest status (e.g. high mobility, high fecundity) also assist adaptation to change.
Climate change as differentially on the phenology (seasonality) of different trophic levels, primary producers advancing their seasonality more rapidly than primary consumers, and these more than secondary consumers. This leads to potential "trophic mismatch" and hence disruption of ecological processes.
Invasion by the harlequin ladybird has led to declines in some native ladybird species.
Culicoides midge vectors of blue-tongue disease have become more abundant over the past 40 years, their flight seasonality has advanced by more than a day per year and the duration of their flying season increased.
The distribution of two species of aphid drives the distribution of different genotypes of wild Arabidopsis thaliana with different chemical defence mechanisms against the insects.
The important cereal aphid pest Schizaphis graminum (greenbug) is not present in the UK, but two very closely related species feeding on wild grasses have been much more abundant in the last 20 years for unknown reasons worthy of further investigation.
Exploitation Route The work continues under project BBS/E/C/00005191. The data will continue to be used in a wide range of projects spanning the complete fundamental to applied spectrum, all aimed ultimately at rationalising decisions in pest control and conservation.
Sectors Agriculture, Food and Drink,Environment

URL http://www.rothamsted.ac.uk/insect-survey
 
Description The long-term data (which have been assembled under this and previous projects) from both the suction-trap and light-trap networks have been used to attract funding for a wide range of projects spanning the full spectrum of fundamental to applied science. At the more applied end, the information on aphids is used continuously to inform the farming industry of current risks from aphids and the viruses they transmit. Information is also provided on the insecticide-resistance status of key species, enabling rational control decisions and optimum stewardship of the increasingly limited range of active ingredients. Weekly bulletins are distributed widely and many talks given to the grower community. The aphid data were also used in a project that determined the true identity of an aphid thought to be the highly noxious pest of cereals known as "greenbug". This aphid is not currently present in the UK, and the species that caused initial concern turned out to be very closely related species feeding only on wild grasses. The group is always watchful for potential new pests. The suction-traps also yield data on insects other than aphids and, over the period of the project, increasing extent of these data has spawned additional funding and publications. Particular highlights were collaboration in studies of (with CEH and Oxford University) declines in native ladybirds as a result of invasion of the harlequin ladybird, and studies (with The Pirbright Institute and CEH) of the changing dynamics of the culicoides midge vectors of blue-tongue virus of sheep and cattle. The use of the data in the latter study led to a re-evaluation of the so-called "vector-free period" during which it is considered safe to move livestock in an outbreak situation. Data from the light-trap network have been used to chart the changing fortunes of British moths and have contributed to high profile reports such as the RSPB's "State of Nature" and Butterfly Conservation's "State of British Moths". Only once trends are clear is it possible to examine the reasons behind them and seek mitigation measures. The Rothamsted Insect Survey are widely recognised as being extremely important in this regard. As a result of the long-term, standardised nature of the data from both networks, the project is uniquely placed to research climate change impacts on insects by using statistical techniques. This leads to hypotheses on causes that can be tested by the group, often in collaboration with others. Work in this area has included studying the changing impact of climate in synchronising population dynamics over different distances, important in understanding the geographical scale that is relevant to forecasting climate change impacts. The data have also been used in a multi-partner project led by CEH examining the impacts of climate change in disturbing the ecological equilibrium between trophic levels, very important in assessing the risks in pest control and conservation issues of the future. A key aspect of the data assembled through this and previous projects is the wide range of, sometimes unexpected, uses to which they are put. A good example is an approach we had from colleagues in Switzerland the USA who had a theory that natural enemies can drive geographic variation in plant defences. Only because our data collection system has been standardised and used by others across Europe was it possible to support this theory with real data. A high profile publication in the journal Science resulted.
Sector Agriculture, Food and Drink,Environment
Impact Types Economic,Policy & public services

 
Title PAUL 
Description A new database recording aphids and other insects from the UK and European suction-trap network is being developed. Once complete it will be possible for collaborators to acquire data direct from a website instead of us downloading it and forwarding it. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact This should enhance collaborative potential and save the group time.