Responses of phytophagous insects to a changing flora

Roy, Helen E.; Bantock, Tristan; Botham, Marc; Preston, Chris D.; Roy, David B.; Stewart, Alan. 2012 Responses of phytophagous insects to a changing flora. [Keynote] In: A Great Leap Forward – Biological Recording since the 1962 Atlas of the British Flora, Edinburgh, 20-21 Sept 2012. (Unpublished)

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Changes in the distribution of the British flora have been well documented (Preston et al., 2002; Braithwaite et al., 2006). One might expect phytophagous insects, particularly host plant specialists, to respond to such changes, as they are dependent on plants for their food supply. However, large-scale assessments of the changes in distribution of insect taxa are rare, even though insects represent a major component of terrestrial biodiversity and there has been a long tradition of biological recording. In particular, the absence for most insect groups of repeat national surveys has limited the extent to which we can compare surveys at different time-periods. However, changes in the ranges of many species over time can be identified from the available sequence of records, and current research is providing more rigorous techniques to extract trend information from continuous records (Hill, 2011). Furthermore, phytophagous insects may respond to changes in the availability of food plants growing as agricultural crops, in parks and gardens and in the wild, whereas botanical studies usually provide information solely on wild populations. Assessment of insect population trends in relation to plant distributions are also complicated by the fact that other aspects of the environment have been changing simultaneously. We will review emerging evidence from analyses of insect distribution datasets in relation to changes in the distribution of plants alongside the effects of climate change, the arrival of non-native species and habitat modification. Lepidoptera are the most extensively studied group of insects in the UK and as such provide a wealth of evidence highlighting changes in the geographical range, abundance, phenology and biotic interactions of species. Some species of Lepidoptera have switched hosts in recent years. The Brown Argus butterfly, Aricia agestis, has expanded its distribution northwards in the UK, spreading away from calcareous grassland habitats (where its main host plant is Helianthemum nummularium) into other types of grassland, where its larvae feed on Geraniaceae species (mainly Geranium molle and Erodium cicutarium). This change in host plant association has been facilitated by warming climate rather than changes to the distribution of plants. The arrival and spread of non-native plants has been one of the most noticeable changes to the UK landscape. There are many documented examples of the arrival and establishment of non-native phytophagous insects which are dependent on these non-native plants. The planthopper, Prokelisia marginata, on cordgrass, Spartina anglica, provides one such example. There are a number of conifer-specialists that have recently arrived in Britain and are feeding on conifers within parks and gardens. The western conifer seed bug Leptoglossus occidentalis, native to North America, arrived in Britain in 2008. Some native insects are also benefiting from the proliferation of conifers in gardens. Eremocoris fenestratus was historically associated with junipers in the Chilterns and had not been recorded since the 1960s until 2010 when specimens of this bug were found on garden cypresses in London. Here we provide examples of changes in the distribution patterns of phytophagous insects in response to changing flora and interactions with environmental change. We conclude that change in the distribution of host plants is simply one of several simultaneous environmental changes to which phytophagous insects are responding. Braithwaite, M.E., Ellis, R.W. & Preston, C.D. 2006. Change in the British Flora 1987-2004. Botanical Society of the British Isles, London. Hill, M.O. 2011. Local frequency as a key to interpreting species occurrence data when recording effort is not known. Methods in Ecology and Evolution, 3, 195-205. Preston, C.D., Pearman, D.A. & Dines, T.D., eds 2002. New atlas of the British & Irish flora. Oxford University Press, Oxford.

Item Type: Publication - Conference Item (Keynote)
Programmes: CEH Topics & Objectives 2009 - 2012 > Biodiversity > BD Topic 3 - Managing Biodiversity and Ecosystem Services in a Changing Environment > BD - 3.3 - Develop integrated environmental assessments and modelling ...
UKCEH and CEH Sections/Science Areas: Pywell
NORA Subject Terms: Ecology and Environment
Date made live: 13 Nov 2012 14:59 +0 (UTC)

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