Matthew Thomas - Academia.edu (original) (raw)

Papers by Matthew Thomas

Ecological Entomology, 2005

Malaria Journal, 2012

Background: New products aimed at augmenting or replacing chemical insecticides must have operati... more Background: New products aimed at augmenting or replacing chemical insecticides must have operational profiles that include both high efficacy in reducing vector numbers and/or blocking parasite transmission and be long lasting following application. Research aimed at developing fungal spores as a biopesticide for vector control have shown considerable potential yet have not been directly assessed for their viability after long-term storage or following application in the field.

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protect... more 1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere.

Agricultural and Forest Entomology, 2000

1 Thermal behaviour of the variegated grasshopper, Zonocerus variegatus, was investigated in the ... more 1 Thermal behaviour of the variegated grasshopper, Zonocerus variegatus, was investigated in the humid tropical zone of southern Benin, west Africa, in the dry seasons of 1996 and 1998. In 1998, investigations included studies of a population of grasshoppers sprayed with an oil-based formulation of the entomopathogenic fungus Metarhizium anisopliae var acridum. 2 Body temperature measurements and observations of thermal behaviour both in the ®eld and on thermal gradients in the laboratory, suggest that Z. variegatus was not an active behavioural thermoregulator. Although it did show shade-seeking behaviour at high temperatures, no overt behavioural postures or microhabitat selection associated with heat gain and elevation of body temperatures was observed. Moreover, no alterations to thermal behaviour were found in response to infection by Metarhizium. 3 Body temperatures exhibited by Z. variegatus in the ®eld will lengthen disease incubation of M. anisopliae var acridum compared with laboratory maintained, constant temperature conditions and may have a signi®cant impact on pathogens with a lower thermal tolerance. 4 Habitat structure appeared to be an important factor determining the extent of body temperature elevation. The effect of habitat differences on infection and growth of M. anisopliae var acridum and other entomopathogenic fungi is discussed.

Pesticide Science, 1997

The residual infectivity of an oil formulation of the fungal entomopathogen Metarhizium ýavovirid... more The residual infectivity of an oil formulation of the fungal entomopathogen Metarhizium ýavoviride was measured during a üeld trial against the rice grasshopper, Hieroglyphus daganensis, in north Benin.

The American journal of tropical medicine and hygiene, Jan 10, 2015

The unprecedented global efforts for malaria elimination in the past decade have resulted in alte... more The unprecedented global efforts for malaria elimination in the past decade have resulted in altered vectorial systems, vector behaviors, and bionomics. These changes combined with increasingly evident heterogeneities in malaria transmission require innovative vector control strategies in addition to the established practices of long-lasting insecticidal nets and indoor residual spraying. Integrated vector management will require focal and tailored vector control to achieve malaria elimination. This switch of emphasis from universal coverage to universal coverage plus additional interventions will be reliant on improved entomological monitoring and evaluation. In 2010, the National Institutes for Allergies and Infectious Diseases (NIAID) established a network of malaria research centers termed ICEMRs (International Centers for Excellence in Malaria Research) expressly to develop this evidence base in diverse malaria endemic settings. In this article, we contrast the differing ecolog...

Scientific reports, 2015

Malaria parasites alter mosquito feeding behaviour in a way that enhances parasite transmission. ... more Malaria parasites alter mosquito feeding behaviour in a way that enhances parasite transmission. This is widely considered a prime example of manipulation of host behaviour to increase onward transmission, but transient immune challenge in the absence of parasites can induce the same behavioural phenotype. Here, we show that alterations in feeding behaviour depend on the timing and dose of immune challenge relative to blood ingestion and that these changes are functionally linked to changes in insulin signalling in the mosquito gut. These results suggest that altered phenotypes derive from insulin signalling-dependent host resource allocation among immunity, blood feeding, and reproduction in a manner that is not specific to malaria parasite infection. We measured large increases in mosquito survival and subsequent transmission potential when feeding patterns are altered. Leveraging these changes in physiology, behaviour and life history could promote effective and sustainable contr...

PloS one, 2015

Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatu... more Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range ...

Pesticide Science, 1996

A study was carried out to investigate the relative infectivity of aerial and submerged conidia o... more A study was carried out to investigate the relative infectivity of aerial and submerged conidia of Metarhizium Javouiride to Schistocerca gregaria and Zonocerus uariegatus. The effect of formulation and application method on initial infectivity and field persistence of these conidia was investigated.

Outlooks on Pest Management, 2006

Trends in parasitology, 2014

Vector life-history traits and parasite development respond in strongly nonlinear ways to changes... more Vector life-history traits and parasite development respond in strongly nonlinear ways to changes in temperature. These thermal sensitivities create the potential for climate change to have a marked impact on disease transmission. To date, most research considering impacts of climate change on vector-borne diseases assumes that all populations of a given parasite or vector species respond similarly to temperature, regardless of their source population. This may be an inappropriate assumption because spatial variation in selective pressures such as temperature can lead to local adaptation. We examine evidence for local adaptation in disease vectors and present conceptual models for understanding how local adaptation might modulate the effects of both short- and long-term changes in climate.

PLoS ONE, 2014

Adult female mosquitoes need blood to develop their eggs and both sexes use nectar and honeydew a... more Adult female mosquitoes need blood to develop their eggs and both sexes use nectar and honeydew as carbohydrate resources for flight, survival and to enhance reproduction. However, there are also a few reports in the literature of mosquitoes feeding on haemolymph of soft-bodied insects such as caterpillars. The frequency and significance of this entomophagous behavior is not well understood, but is thought to be a vestige of ancestral feeding behavior or an opportunistic behavior that has evolved over time. In our current paper we investigated the extent to which the malaria mosquito, Anopheles stephensi, is attracted to, and can successfully feed on, larvae of two common moth species, Manduca sexta and Heliothis subflexa. Using y-tube olfactometer assays we found that female An. stephensi readily flew upwind to and landed on the caterpillars of both moth species. The nature of the volatile cues used in host location remains unclear but respirometer studies suggest a possible role of CO 2 . Laboratory cage assays further showed that the female mosquitoes were able to actively feed on moth larvae and gain sufficient nutritional benefit to influence survival. The extent to which such an opportunistic behavior occurs in the field has yet to be explored but our results suggest that this haemolymph feeding behavior could play a role in malaria mosquito life history and could provide a novel mechanism for horizontal transmission of pathogens and other micro-organisms between hosts.

Progress in Biological Control, 2006

Page 1. Chapter # TROPHIC AND GUILD INTERACTIONS AND THE INFLUENCE OF MULTIPLE SPECIES ON DISEASE... more Page 1. Chapter # TROPHIC AND GUILD INTERACTIONS AND THE INFLUENCE OF MULTIPLE SPECIES ON DISEASE Matt B. Thomas1,2, Steve P. Arthurs1 and Emma L. Watson1 1NERC Centre for Population Biology, Imperial ...

Scientific Reports, 2014

Very recently, the Asian malaria vector (Anopheles stephensi) was stably transinfected with the w... more Very recently, the Asian malaria vector (Anopheles stephensi) was stably transinfected with the wAlbB strain of Wolbachia, inducing refractoriness to the human malaria parasite Plasmodium falciparum. However, conditions in the field can differ substantially from those in the laboratory. We use the rodent malaria P. yoelii, and somatically transinfected An. stephensi as a model system to investigate whether the transmission blocking potential of wAlbB is likely to be robust across different thermal environments. wAlbB reduced malaria parasite prevalence and oocyst intensity at 286C. At 246C there was no effect on prevalence but a marked increase in oocyst intensity. At 206C, wAlbB had no effect on prevalence or intensity. Additionally, we identified a novel effect of wAlbB that resulted in reduced sporozoite development across temperatures, counterbalancing the oocyst enhancement at 246C. Our results demonstrate complex effects of temperature on the Wolbachia-malaria interaction, and suggest the impacts of transinfection might vary across diverse environments. OPEN SUBJECT AREAS: ECOLOGY MOLECULAR BIOLOGY ECOPHYSIOLOGY

Nature communications, 2010

Predicting and ranking potential invasive species present significant challenges to researchers a... more Predicting and ranking potential invasive species present significant challenges to researchers and biosecurity agencies. Here we analyse a worldwide database of pest species assemblages to generate lists of the top 100 insect pests most likely to establish in the United States and each of its 48 contiguous states. For the United States as a whole, all of the top 100 pest species have already established. Individual states however tend to have many more 'gaps' with most states having at least 20 species absent from their top 100 list. For all but one state, every exotic pest species currently absent from a state's top 100 can be found elsewhere in the contiguous United States. We conclude that the immediate threat from known invasive insect pests is greater from within the United States than without. Our findings have potentially significant implications for biosecurity policy, emphasizing the need to consider biosecurity measures beyond established national border inter...

Agricultural and Forest Entomology, 1999

1 The role of pathogens in insect population dynamics remains poorly understood and their perform... more 1 The role of pathogens in insect population dynamics remains poorly understood and their performance in biological control is erratic. Here we identify that temperature and host thermal behaviour, both the active interaction with environmental temperature and solar radiation via thermoregulation and the passive interception of these factors by thermal generalists, are central to understanding host±pathogen interactions. 2 We demonstrate that pathogenicity, the latent period of infection and host recovery rate can all vary dramatically across and between seasons due to thermal biology of the host and changes in environmental temperature. 3 Such effects have not been thoroughly explored in any previous investigations but may have major implications for disease dynamics in insects and possibly in ectotherms in general, and for development of effective biopesticides.

Trends in Ecology & Evolution, 2011

The notion that climate change will generally increase human and wildlife diseases has garnered c... more The notion that climate change will generally increase human and wildlife diseases has garnered considerable public attention, but remains controversial and seems inconsistent with the expectation that climate change will also cause parasite extinctions. In this review, we highlight the frontiers in climate change-infectious disease research by reviewing knowledge gaps that make this controversy difficult to resolve. We suggest that forecasts of climate-change impacts on disease can be improved by more interdisciplinary collaborations, better linking of data and models, addressing confounding variables and context dependencies, and applying metabolic theory to host-parasite systems with consideration of community-level interactions and functional traits. Finally, although we emphasize host-parasite interactions, we also highlight the applicability of these points to climate-change effects on species interactions in general.