The ecology of aphid hyperparasitoids
Shaw, J.V.M (2023) The ecology of aphid hyperparasitoids. Doctoral thesis, Harper Adams University.
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Jenna Shaw_Final Thesis_MPhil_Ecology of aphid Hyperparasitoids.pdf Download (1MB) | Preview |
Abstract
Aphids are economically important pests of protected horticulture crops such as sweet pepper (Capsicum annum Linnaeus 1753). Their control is partially achieved through augmentation biological control programmes based on supplemental releases of mass-reared primary parasitoid wasps. The efficacy of primary parasitoid wasps is, however, negatively impacted by naturally occurring hyperparasitoid wasps within the cropping environment. This project aimed to build upon existing knowledge of hyperparasitoid biology and ecology to aid the development of management tools that improve aphid IPM efficacy in UK protected sweet pepper crops. Experiments focussed on Myzus persicae Sulzer 1776, six commercially available primary parasitoid species: Aphidius colemani Viereck 1912, A. ervi Viereck 1912, A. matricariae Viereck 1912, Aphelinus abdominalis Dalman 1820, Ephedrus cerasicola Satry 1962 and Praon volucre Haliday 1833 and Asaphes suspensus Nees 1834, a hymenopteran hyperparasitoid common in United Kingdom sweet pepper cropping systems. The development of these species was observed and recorded with M. persicae taking, a mean of, seven to eight days to reach reproductive adulthood from first instar nymphs. The three Aphidius species took a mean of 13 to 14 days to develop from the point of oviposition to adult emergence, E. cerasicola took just between 14 and 15 days a mean of, P. volucre took the longest time with a mean of 17.4 days. Asaphes suspensus took between 17 and 19 days to fully develop from oviposition to emerging adult which was not significantly affected by which of the six parasitoid species it used as its host. This shows that hyperparasitoid development is not affected by which primary parasitoid species is used by a grower for aphid control. The apparent preference of primary parasitoids for specific aphid host developmental stage was investigated using choice and no-choice experiments offering individual parasitoid species M. persicae of different ages. This study validates previous studies that conclude A. colemani has higher parasitism levels in third instar M. persicae over all other life stages when given no choice between aphid developmental stage but also selected third instar aphids the most when given a choice of aphids at different developmental stages (Sampaio et al., 2008). Experiments carried out in Chapter Four investigated the impact of hyperparasitoid presence on a host plant has on primary parasitoid foraging behaviour. This experiment demonstrated that primary parasitoids parasitised fewer aphids when there had been four or eight hyperparasitoids previously present on the leaf, likely suggesting hyperparasitoids deposit a non-volatile semiochemical cue that the primary parasitoid detects and that might affect their oviposition success. This research has provided a foundation for hyperparasitoid research to develop the chemical ecology of hyperparasitoids and their use of semiochemicals in host selection. Further information on this could be used in developing hyperparasitoid monitoring and control techniques in the UK’s protected sweet pepper crops.
| Item Type: | Thesis (Doctoral) |
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| Divisions: | Agriculture and Environment (from 1.08.20) |
| Depositing User: | Mrs Terésa-Marie Brown |
| Date Deposited: | 14 Nov 2024 17:07 |
| Last Modified: | 14 Nov 2024 17:07 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/18148 |
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