Interactions between aphids, their insect and fungal natural enemies and the host plant

Multitrophic and intraguild interactions influence the success of biological control. The interactions between Acyrthosiphon pisum, three natural enemies (Pandora neoaphidis, Coccinella septempunctata and Aphidius ervi) and the host plant, Vicia faba, were assessed. Volatiles released from aphid-damaged plants had a direct effect on P. neoaphidis indicating they may act as synomones. However, volatiles did not increase efficacy of the fungus suggesting it is not a bodyguard species. Transmission was greatest during plant colonisation by aphids and was not affected by plant condition. Infection by P. neoaphidis had a direct negative effect on the fitness of the aphid through reduced reproduction and early host death. Avoidance of infected colonies by predators and parasitoids could reduce the effectiveness of guilds of natural enemies for biological control. However, at the laboratory scale A. ervi and C. septempunctata did not detect infection and entered and foraged in infected aphid colonies. Aphidius ervi spent longer searching for hosts on plants that had been damaged by aphid feeding (and were emitting aphid-induced species-specific volatiles) and this may increase fungal transmission. Coccinella septempunctata and A. ervi significantly reduced populations of A. pisum when introduced as individual species whereas P. neoaphidis had no effect on aphid population size. Foraging by both C. septempunctata and A. ervi increased the abundance and distribution of P. neoaphidis which may be sufficient to initiate an epizootic. The benefits of increased transmission by C. septempunctata outweighed the fitness costs to the fungus of intraguild predation. Pandora neoaphidis was associated with a decrease in the reproductive success of A. ervi, which was further reduced as the competitive advantage of the fungus increased. This could result in competitive exclusion of the parasitoid. Poly tunnel experiments confirmed that A. ervi did not discriminate between infected and uninfected aphid colonies at this spatial scale. However, A. ervi did not incur a fitness cost from foraging in patches containing the fungus. These results indicate that C. septempunctata and P. neoaphidis may be effective as multi-species biocontrol agents. In contrast, competition between P. neoaphidis and A. ervi may reduce their overall effectiveness as control agents. Further work is required at larger spatial scales and over several generations of both the pest and natural enemy species to confirm these interactions. The implications of these results for the use of P. neoaphidis as part of a multi-species biological control program are discussed

Interactions between aphids, their insect and fungal natural enemies and the host plant

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Interactions between aphids, their insect and fungal natural enemies and the host plant

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Manipulating fungal induced host-altered behaviour: a strategy for pest control?

The behavioural responses of insects to stimuli are extremely varied and can be manipulated as a strategy for pest control. For example our understanding of insect semiochemistry has enabled the development of novel pest control methods involving lures and repellents. Fungal pathogens (and indeed other pathogens and parasites) of insects are also known to alter insect behaviour. In most cases the behavioural alterations are not immediately applicable to pest management strategies but recent studies have demonstrated the importance of understanding the intricate nature of interactions between pathogens and their hosts particularly when the pathogen is being considered as a biological control agent. In this chapter we explore the way in which insect behaviour can be manipulated to enhance pathogen dissemination. We focus on linking current theory and understanding of insect behavioural manipulation with applications

Intraguild predation involving Harmonia axyridis: a review of current knowledge and future perspectives.

As an effective generalist predator of aphids and other hemipteran pests H. axyridis has been a successful biological control agent. However, the very functional traits that have contributed to its success in this regard also implicate it as an intraguild predator that poses a significant risk not only to the diversity of other natural enemies of Hemiptera (and their associated ecosystem services), but to biodiversity more widely. In this paper we will specifically review the existing data on intraguild predation involving H. axyridis, and consider the strength and symmetry of such interactions both within its native guild and within exotic guilds where it has established as an invasive alien. We will use these studies to interpret the observed population declines in predator diversity in the field, predict species at risk in regions not yet invaded and consider implications for resulting ecosystem services. We will also indicate gaps in our knowledge that require further study in order to identify opportunities for mitigation

Whose Book Is it Anyway?

Whose Book is it Anyway? is a provocative collection of essays that opens out the copyright debate to questions of open access, ethics, and creativity. It includes views — such as artist's perspectives, writer's perspectives, feminist, and international perspectives — that are too often marginalized or elided altogether. The diverse range of contributors take various approaches, from the scholarly and the essayistic to the graphic, to explore the future of publishing based on their experiences as publishers, artists, writers and academics. Considering issues such as intellectual property, copyright and comics, digital publishing and remixing, and what it means (not) to say one is an author, these vibrant essays urge us to view central aspects of writing and publishing in a new light. Whose Book is it Anyway? is a timely and varied collection of essays. It asks us to reconceive our understanding of publishing, copyright and open access, and it is essential reading for anyone invested in the future of publishing. As with all Open Book publications, this entire book is available to read for free on the publisher's website. Printed and digital editions, together with supplementary digital material, can also be found at www.openbookpublishers.co