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Loss of effective antibiotics through antimicrobial resistance (AMR) is one of the greatest threats to human health. By 2050, the annual death rate resulting from AMR infections is predicted to have climbed from 1.27 million per annum in 2019, up to 10 million per annum. It is therefore imperative to preserve the effectiveness of both existing and future antibiotics, such that they continue to save lives. One way to conserve the use of existing antibiotics and build further contingency against resistant strains is to develop alternatives. Non-biological complex drugs (NBCDs) are an emerging class of therapeutics that show multi-mechanistic antimicrobial activity and hold great promise as next generation antimicrobial agents. We critically outline the focal advancements for each key material class, including antimicrobial polymer materials, carbon nanomaterials, and inorganic nanomaterials, and highlight the potential for the development of antimicrobial resistance against each class. Finally, we outline remaining challenges for their clinical translation, including the need for specific regulatory pathways to be established in order to allow for more efficient clinical approval and adoption of these new technologies.

Context African production landscapes are diverse, with multiple cassava cultivars grown in small patches amongst a diversity of other crops. Studies on how diverse smallholder landscapes impact herbivore pest outbreak risk have not been carried out in sub-Saharan Africa. Objectives Bemisia tabaci is a cryptic pest species complex that cause damage to cassava through feeding and vectoring plant-virus diseases and are known to reach very high densities in certain contexts. However, the factors driving this phenomenon are unclear. Methods Bemisia density data in cassava across a large number of sites representing a geographic gradient across Uganda, Tanzania and Malawi were collected. We tested whether in-field or landscape factors associated with land-use patterns underpinned Bemisia density variability and parasitism. Results We found the B. tabaci SSA1 species dominated our study sites, although other species were also common in some cassava fields. Factors associated with the surrounding landscape were unimportant for explaining variability in adult density, but the in-field variables of cassava age and cultivar were very important. The density of nymphs and the parasitism of nymphs was heavily influenced by a diversity of landscape factors surrounding the field, including the size of focal cassava field, and area of cassava in the landscape. However, unlike the trend from many other studies on drivers of natural enemy populations, this pattern was not solely related to the amount of non-crop vegetation, or the diversity of crops grown in the landscape. Conclusions Our findings provide management options to reduce whitefly abundance, including describing the characteristics of landscapes with high parasitism. The choice of cassava cultivar by the farmer is critical to reduce whitefly outbreak risk at the landscape-scale.

Refereed/Peer-reviewed The spread of antimicrobial resistance (AMR) is a rapidly growing threat to humankind on both regional and global scales. As countries worldwide prepare to embrace a One Health approach to AMR management, which is one that recognizes the interconnectivity between human, animal, and environmental health, increasing attention is being paid to identifying and monitoring key contributing factors and critical control points. Presently, AMR sensing technologies have significantly progressed phenotypic antimicrobial susceptibility testing (AST) and genotypic antimicrobial resistance gene (ARG) detection in human healthcare. For effective AMR management, an evolution of innovative sensing technologies is needed for tackling the unique challenges of interconnected AMR across various and different health domains. This review comprehensively discusses the modern state-of-play for innovative commercial and emerging AMR sensing technologies, including sequencing, microfluidic, and miniaturized point-of-need platforms. With a unique view toward the future of One Health, we also provide our perspectives and outlook on the constantly changing landscape of AMR sensing technologies beyond the human health domain.

Management of agricultural pests requires an understanding of pest species diversity, their interactions with beneficial insects and spatial-temporal patterns of pest abundance. Invasive and agriculturally important insect pests can build up very high populations, especially in cropping landscapes. Traditionally, sampling effort for species identification involves small sample sizes and is labour intensive. Here, we describe a multiprimer high throughput sequencing (HTS) metabarcoding method and associated analytical workflow for a rapid, intensive, high-volume survey of pest species compositions. We demonstrate our method using the taxonomically challenging Bemisia pest cryptic species complex as examples. The whiteflies Bemisia including the"tabaci" species are agriculturally important capable of vectoring diverse plant viruses that cause diseases and crop losses. Our multiprimer metabarcoding HTS amplicon approach simultaneously process high volumes of whitefly individuals, with efficiency to detect rare (i.e., 1%) test-species, while our improved whitefly primers for metabarcoding also detected beneficial hymenopteran parasitoid species from whitefly nymphs. Field-testing our redesigned Bemisia metabarcoding primer sets across the Tanzania, Uganda and Malawi cassava cultivation landscapes, we identified the sub-Saharan Africa 1 Bemisia putative species as the dominant pest species, with other cryptic Bemisia species being detected at various abundances. We also provide evidence that Bemisia species compositions can be affected by host crops and sampling techniques that target either nymphs or adults. Our multiprimer HTS metabarcoding method incorporated two overlapping amplicons of 472 bp and 518 bp that spanned the entire 657 bp 3' barcoding region for Bemisia, and is particularly suitable to molecular diagnostic surveys of this highly cryptic insect pest species complex that also typically exhibited high population densities in heavy crop infestation episodes. Our approach can be adopted to understand species biodiversity across landscapes, with broad implications for improving transboundary biosecurity preparedness, thus contributing to molecular ecological knowledge and the development of control strategies for high-density, cryptic, pest-species complexes.

Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the "Debug" Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

Significance With over 40% of humans at risk from mosquito-borne diseases such as dengue, yellow fever, chikungunya, and Zika, the development of environmentally friendly mosquito-control tools is critical. The release of reproductively incompatible male mosquitoes carrying a Wolbachia bacterium can drive mating events that kill the eggs. Through replicated treatment and control experiments in northern Australia, regular releases of Aedes aegypti males infected with a Wolbachia from Aedes albopictus was shown to drive strong population suppression in mosaic populations of wild-type (no Wolbachia) and wMel-Wolbachia–carrying Ae. aegypti. In a demonstration of bidirectional incompatibility between different Wolbachia strains in the field, we also demonstrate that one season’s suppression experiment can also show an ongoing effect into the following season., Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the “Debug” Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

Self-medication with antibiotics is a major contributing factor to antimicrobial resistance. Prior research examining factors associated with antibiotic self-medication has focused on an individual’s knowledge about antibiotics, antibiotic usage practices, accessibility to antibiotic medication, and demographic characteristics. The role of psychological distress associated with perceived health risks in explaining antibiotic self-medication is less understood. This study was designed to address this knowledge gap in the context of the COVID-19 pandemic in Australia. An online survey of 2217 participants was conducted at the height of the initial outbreak and revealed that 19.5% of participants took antibiotics to protect themselves from COVID-19. Multivariate logistic analysis examined the predictors of taking antibiotics for protection against COVID-19. An integrative framework developed from the results illustrates potential pathways and facilitating factors that may contribute to prophylactic self-medication with antibiotics. Specifically, COVID-19 pandemic-induced psychological distress was significantly positively related to self-medication. Preventive use of antibiotics was also facilitated by a lack of understanding about antibiotics, inappropriate antibiotics usage practices, the nature of the patient-doctor relationship, and demographic characteristics. The findings highlight that to combat antimicrobial resistance due to self-medication, interventions need to focus on interrupting entrenched behavioural responses and addressing emotional responses to perceived health risks.

Projected climate changes are thought to promote emerging infectious diseases, though to date, evidence linking climate changes and such diseases in plants has not been available. Cassava is perhaps the most important crop in Africa for smallholder farmers. Since the late 1990’s there have been reports from East and Central Africa of pandemics of begomoviruses in cassava linked to high abundances of whitefly species within the Bemisia tabaci complex. We used CLIMEX, a process-oriented climatic niche model, to explore if this pandemic was linked to recent historical climatic changes. The climatic niche model was corroborated with independent observed field abundance of B. tabaci in Uganda over a 13-year time-series, and with the probability of occurrence of B. tabaci over 2 years across the African study area. Throughout a 39-year climate time-series spanning the period during which the pandemics emerged, the modelled climatic conditions for B. tabaci improved significantly in the areas where the pandemics had been reported and were constant or decreased elsewhere. This is the first reported case where observed historical climate changes have been attributed to the increase in abundance of an insect pest, contributing to a crop disease pandemic.

Synthetic gene drives could provide new solutions to a range of old problems such as controlling vector-borne diseases, agricultural pests and invasive species. In this paper, we outline methods to identify hazards and detect potentially adverse ecological outcomes at the individual (genotype, phenotype), population, community and ecosystem level, when progressing Gene Drive Modified Organisms through a phased test and release pathway. We discuss the strengths and weaknesses of checklists and structured hazard analysis techniques, identify methods to help meet some of the challenges of detecting adverse ecological outcomes in experiments and confined field trials, and discuss ways to improve the efficiency and statistical rigour of post-release monitoring strategies.

BACKGROUND This study examines whether leaf spectra can be used to measure damage to cassava plants from whitefly (Bemisia tabaci), and the potential to translate measurements from leaf to landscape scale in eastern Africa. Symptoms of the cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) viruses, and sooty mould (SM) blackening of lower leaves from whiteflies feeding on the upper leaves, were measured at the leaf scale with a high resolution spectroradiometer and a SPAD meter, which retrieves relative chlorophyll concentration. Spectral measurements were compared to the 5-level visual scores that used to assess the severity of each of the three damaging agents in the field, and also to leaf chemistry data. RESULTS Leaves exhibiting severe CBSD and CMD are spectrally indistinguishable from leaves without any symptoms. Severe SM is spectrally distinctive but likely to be difficult to map due to its occurrence in the lower crown. SPAD measurements are highly correlated with most foliar chemistry measurements and field scores of disease severity. Models between simulated Sentinel 2 bands, field scores and SPAD measurements are strongest using wavelengths with high importance weightings in random forest models. CONCLUSION SPAD measurements are highly correlated to many foliar chemistry parameters, and should be considered for use in mapping disease severity over larger areas. Remaining challenges for mapping relate to the subtle expression of symptoms, the spatial distribution of disease severity within fields, and the small size and complex structure of the cassava fields themselves.

BACKGROUND The whitefly Bemisia tabaci complex harbours over 40 cryptic species that have been placed in 11 phylogenetically distinct clades based on the molecular characterisation of partial mitochondrial DNA COI (mtCOI) gene region. Four cryptic species are currently within the invasive clade i.e. ‘MED’, ‘MEAM1’, ‘MEAM2’ and IO’. Correct identification of these species is a critical step towards implementing reliable measures for plant biosecurity and border protection, however no standardised B. tabaci-specific primers are currently available which has caused inconsistencies in the species identification processes. RESULTS We report three sets of PCR primers developed to amplify the mtCOI region which can be used for genotyping ‘MED’, ‘MEAM1’, and ‘IO’ species and tested these primers on 91 MED, 35 MEAM1 and five IO individuals. PCR and sequencing of amplicons identified a total of 21, six and one haplotypes in MED, MEAM1 and IO respectively, of which six haplotypes were new to the B. tabaci database. CONCLUSION These primer pairs enabled standardisation and robust molecular species identification via mtCOI screening of the targeted invasive cryptic species and will improve quarantine decisions. The use of this diagnostic tool could be extended to other species within the complex.

Molecular species identification using suboptimal PCR primers can over-estimate species diversity due to coamplification of nuclear mitochondrial (NUMT) DNA/pseudogenes. For the agriculturally important whitefly Bemisia tabaci cryptic pest species complex, species identification depends primarily on characterization of the mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene. The lack of robust PCR primers for the mtDNA COI gene can undermine correct species identification which in turn compromises management strategies. This problem is identified in the B. tabaci Africa/Middle East/Asia Minor clade which comprises the globally invasive Mediterranean (MED) and Middle East Asia Minor I (MEAM1) species, Middle East Asia Minor 2 (MEAM2), and the Indian Ocean (IO) species. Initially identified from the Indian Ocean island of Réunion, MEAM2 has since been reported from Japan, Peru, Turkey and Iraq. We identified MEAM2 individuals from a Peruvian population via Sanger sequencing of the mtDNA COI gene. In attempting to characterize the MEAM2 mitogenome, we instead characterized mitogenomes of MEAM1. We also report on the mitogenomes of MED, AUS, and IO thereby increasing genomic resources for members of this complex. Gene synteny (i.e., same gene composition and orientation) was observed with published B. tabaci cryptic species mitogenomes. Pseudogene fragments matching MEAM2 partial mtDNA COI gene exhibited low frequency single nucleotide polymorphisms that matched low copy number DNA fragments (

Invasive species policy could be better informed if we understood how much people value reductions in the risks posed by these organisms. This study investigates the public’s willingness to pay (WTP) for additional measures to reduce the risk of invasion of the Australian mainland by the Asian tiger mosquito (ATM). The study contributes to the literature by applying a stated preference method to estimate the public’s WTP to reduce the risk of an ATM invasion, expressed as a change in probability. It is the first ex ante invasive species analysis to test over two discrete invasion reduction probabilities based on management effort. Further, to overcome the challenges in valuing changes in probabilities, the study presented respondents with a well-defined discrete difference in the final probability, with one scenario reducing risk from 50 to 25% and the other from 50 to 5%. We find a significant difference in the mean WTP values between these two scenarios (A$67 vs. A$90). The overall conclusion is that estimated benefits of reducing the probability of an ATM incursion outweigh the costs.

The United Nations (UN) launched the 2030 Agenda for Sustainable Development to address an ongoing crisis: human pressure leading to unprecedented environmental degradation, climatic change, social inequality, and other negative planet-wide consequences. This crisis stems from a dramatic increase in human appropriation of natural resources to keep pace with rapid population growth, dietary shifts toward higher consumption of animal products, and higher demand for energy (1, 2). There is an increased recognition that Sustainable Development Goals (SDGs) are linked to one another (3, 4), and priorities such as food production, biodiversity conservation, and climate change mitigation cannot be considered in isolation (5⇓⇓–8). Hence, understanding those dynamics is central to achieving the vision of the UN 2030 Agenda. Infectious zoonotic diseases typically emerge as a result of complex interactions between humans and wild and/or domestic animals. Image credit: Pixabay/sasint. But environmental change also has direct human health outcomes via infectious disease emergence, and this link is not customarily integrated into planning for sustainable development. Currently, 65 countries are engaged in the Global Health Security Agenda (GHSA) and are finalizing a strategic plan for the next five years (the GHSA 2024 Roadmap) to better prevent, detect, and respond to infectious disease outbreaks in alignment with SDGs 2 and 3 on food security and human health. Without an integrated approach to mitigating the disease emergence consequences of environmental change, countries’ abilities to achieve SDGs and GHSA targets will be compromised. Emerging infectious diseases (EIDs) such as Ebola, influenza, SARS, MERS, and, most recently, coronavirus (2019-nCoV) cause large-scale mortality and morbidity, disrupt trade and travel networks, and stimulate civil unrest (9). When local emergence leads to regional outbreaks or global pandemics, the economic impacts can be devastating: The SARS outbreak in 2003, the H1N1 pandemic in 2009, and … [↵][1]1To whom correspondence may be addressed. Email: moreno.dimarco{at}uniroma1.it. [1]: #xref-corresp-1-1

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Simple Summary Cassava is one of the most important subsistence crops for smallholder farmers in East and central Africa. Cassava is increasingly infested by the whitefly Bemisia tabaci that transmits two diseases that in combination with the direct feeding damage cause significant yield losses. Land-use changes due to crop rotations can impact pest dynamics but not much is known about these processes in dynamic smallholder production landscapes. This study investigated how seasonal land-use changes impacted B. tabaci and its parasitoids in an agricultural landscape in Uganda using a semi-manipulative field-experiment on smallholder farmers land. The dominant species of B. tabaci on cassava was Sub-Saharan Africa 1 (SSA1), which was also found on some other surrounding crops and weeds. The highest abundance of B. tabaci SSA1 nymphs in cassava fields occurred at times when landscapes had large areas of weeds, low to moderate areas of maize, and low areas of banana. These results are important to guide the development of land-use strategies that smallholder farmers can employ to manage whitefly pests. Abstract Cassava (Manihot esculenta Crantz), an important commercial and food security crop in East and Central Africa, continues to be adversely affected by the whitefly Bemisia tabaci. In Uganda, changes in smallholder farming landscapes due to crop rotations can impact pest populations but how these changes affect pest outbreak risk is unknown. We investigated how seasonal changes in land-use have affected B. tabaci population dynamics and its parasitoids. We used a large-scale field experiment to standardize the focal field in terms of cassava age and cultivar, then measured how Bemisia populations responded to surrounding land-use change. Bemisia tabaci Sub-Saharan Africa 1 (SSA1) was identified using molecular diagnostics as the most prevalent species and the same species was also found on surrounding soybean, groundnut, and sesame crops. We found that an increase in the area of cassava in the 3–7-month age range in the landscape resulted in an increase in the abundance of the B. tabaci SSA1 on cassava. There was a negative relationship between the extent of non-crop vegetation in the landscape and parasitism of nymphs suggesting that these parasitoids do not rely on resources in the non-crop patches. The highest abundance of B. tabaci SSA1 nymphs in cassava fields occurred at times when landscapes had large areas of weeds, low to moderate areas of maize, and low areas of banana. Our results can guide the development of land-use strategies that smallholder farmers can employ to manage these pests.

BACKGROUND The flat grain beetle (FGB) species Cryptolestes ferrugineus, C. pusillus, C. pusilloides and C. turcicus are major stored-product pests worldwide, of which the first three are present in Australia. C. ferrugineus is also a species with high phosphine resistance status in various countries. Morphological identification of Cryptolestes species is difficult and represents an additional barrier to effective management of phosphine resistance in FGBs. RESULT Mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene characterisation enabled differentiation of the four major FGB pest species through direct sequence comparison, and enabled the development of a PCR-RFLP method for rapid species differentiation. We detected two mtDNA haplotypes (Cunk-01, 02) present at low frequencies with an average nucleotide divergence rate of 0.079 ± 0.011 (SE) from C. pusillus. This nucleotide divergence rate is similar to that between C. ferrugineus and C. pusilloides (0.088 ± 0.012). Male and female genitalia morphologies of the Cunk-02 individuals indicated they were consistent with C. pusillus, yet DNA sequence analyses suggested species-level divergence. The mtDNA COI gene of phosphine-bioassayed, lab-reared F1 generation survivors supported the presence of strong phosphine resistance in C. ferrugineus, but unexpectedly also in C. pusilloides and C. pusillus F1 survivors. CONCLUSION We demonstrated the utility of molecular DNA techniques for differentiating closely related insect species, and its usefulness in assisting the management of pest insect species. The likely presence of a cryptic C. pusillus species in Australia and the possible development of strong phosphine resistance in Australian FGB pest species require further investigation. © 2014 Society of Chemical Industry

Extreme risks are challenging to learn from, prepare for and protect against, and they invite the development of new approaches to complement existing methods of risk management. We describe a systematic ex ante approach to support the strategic preparedness of risk management and apply it to a biosecurity case study. Our framework integrates a war-game model and a structured decision making approach. The model provides interactive maps that help stakeholders in visualizing the economic impacts of the extreme risk under different management scenarios, and it facilitates adaptive management by translating science-based results into stakeholder perspectives. The structured decision making approach not only offers an analytical structure to organize the multiple objectives of risk management, but also functions as a platform for group deliberation among alternative courses of management action with uncertain consequences. We found that this integration helped stakeholders develop a better understanding of the complexities and interconnectedness of the extreme risk management and reached a consensus regarding the most preferred management option.

Versatile molecular tools for creating driving transgenes and other invasive genetic factors present regulatory, ethical, and environmental challenges that should be addressed to ensure their safe use. In this article, we discuss driving transgenes and invasive genetic factors that can potentially spread after their introduction into a small proportion of individuals in a population. The potential of invasive genetic factors to increase their number in natural populations presents challenges that require additional safety measures not provided by previous recommendations regarding accidental release of arthropods. In addition to providing physical containment, invasive genetic factors require greater attention to strain management, including their distribution and identity confirmation. In this study, we focus on insects containing such factors with recommendations for investigators who are creating them, institutional biosafety committees charged with ensuring safety, funding agencies providing support, those managing insectaries handling these materials who are responsible for containment, and other persons who will be receiving insects—transgenic or not—from these facilities. We give specific examples of efforts to modify mosquitoes for mosquito-borne disease control, but similar considerations are relevant to other arthropods that are important to human health, the environment, and agriculture.

Members of the whitefly Bemisia tabaci species complex cause millions of dollars of damage globally and are considered one of the world’s most invasive species. They are capable of causing extensive damage to major vegetable, grain legume and fiber crops. All member of the species complex are morphologically identical therefore, data from the partial mitochondrial cytochrome oxidase subunit I (mtCOI) gene sequence has been used to identify the various species. The current reference dataset that is widely used is found on the CSIRO data portal. However, the reference set stored on the CSIRO data does not include newly added sequences (2013-2017), therefore an updated reference dataset is needed. All mtCOI data for the Bemisia tabaci species complex were downloaded on 22 May 2017 from GenBank and after quality checking, a dataset of 1,071 unique sequences and 696 base pairs was generated (https://doi.org/10.6084/m9.figshare.5437420.v1).

We provide the first evidence for interspecific warfare in bees, a spectacular natural phenomenon that involves a series of aerial battles and leads to thousands of fatalities from both attacking and defending colonies. Molecular analysis of fights at a hive of the Australian stingless bee Tetragonula carbonaria revealed that the attack was launched by a related species, Tetragonula hockingsi, which has only recently extended its habitat into southeastern Queensland. Following a succession of attacks by the same T. hockingsi colony over a 4-month period, the defending T. carbonaria colony was defeated and the hive usurped, with the invading colony installing a new queen. We complemented our direct observations with a 5-year study of more than 260 Tetragonula hives and found interspecific hive changes, which were likely to be usurpation events, occurring in 46 hives over this period. We discuss how fighting swarms and hive usurpation fit with theoretical predictions on the evolution of fatal fighting and highlight the many unexplained features of these battles that warrant further study.

Interception data collected at the Australian quarantine border on the orders Coleoptera, Hemiptera, Lepidoptera and Diptera during 1986–2005 were cross-referenced to incursion data. For insects from these four orders, detection at the quarantine border was a poor predictor of successful incursions over the corresponding period. Most species that successfully mounted an incursion during the 1986–2005 period were not recorded as being intercepted at the quarantine border over the same period. This may be due to either organisms arriving via pathways that are not subject to border inspection, or that the inspection sensitivity is low, or that species discovered are not reliably identified, recorded and reported. The end result is that the border inspection, at least during the period 1986–2005, would have been largely ineffective as an early warning system for a large proportion of incursions occurring over that period. This finding is contrary to the expectation that interception data is a useful tool for predicting future incursions and opens the question as to whether different approaches to collecting interception data might improve predictive power. That said, within those species that were intercepted, those with a higher interception rate had an increased probability of a recorded incursion, particularly for incursions before 1986, and so supports the argument that propagule pressure is a key factor in invasion establishment.

This paper takes inspiration from the field of bio-mimicry to suggest what a plant biosecurity system might look like if it was modelled on the human immune system. We suggest structural and institutional changes to current biosecurity systems that would facilitate adaptive preparation and response policies, focusing particularly on the Australian plant biosecurity system. By improving information exchanges, interpretation and managing overlapping complementary response capabilities of this system, novel policies emerge that increase resilience to harmful weeds, pests and diseases. This is achieved by adding an element of flexibility in invasion response to cope with different circumstances and contexts, rather than a 'one size fits all' approach. While we find bio-mimicry to be a potentially useful system design tool, there are key differences between the immune and biosecurity systems that the analogy makes clear. Perhaps the most important of these stems from the inability of immune systems to imagine future threats. (C) 2014 Elsevier Ltd. All rights reserved. (Less)

Human trade and transport is a major contributor to the global spread of invasive species and biodiversity change. Much of the focus on anthropogenic spread has been the movement of species between countries with far less attention being placed on the within country spread. For invasive arthropods, trade in ornamentals is a key contributor to global spread, but the role played by the transport of ornamentals within countries has been less well explored. In China, the hosting of major international events is an important expression of national and international pride and prestige. Hosting these is associated with the substantial use of landscaping to beautify the sites, all of which need to transport considerable numbers of plants to the event sites from various parts of China. To assess the consequences of this in terms of the spread of arthropod pests we sampled ornamental plants used to landscape the 29th Olympic Games in Beijing and the 16th Asia Games in Guangzhou. Plants used to landscape the Olympic Games were transported from ten provinces from across the eastern half of China. A total of 44 species of herbivorous arthropods belonging to six orders were recorded with eight species being new records for Beijing. Plants used at the 16th Asian Games came from five provinces. In total 32 species of arthropod herbivores belonging to six orders were recorded with four being new records for Guangdong province. Our results suggested that measures need to be considered to reduce the likelihood of invasive species spread when hosting major international events.

Bemisia tabaci has had a colorful nomenclatural past and is now recognized as a species complex. This new species framework has added many new areas of research including adding new insight into the virus transmission specificity of the species in the B. tabaci species complex. There is a wide disparity in what is known about the transmission of plant viruses by different members of the B. tabaci species complex. In this paper, we have synthesized the transmission specificities of the plant viruses transmitted by species belonging to the complex. There are five genera of plant viruses with members that are transmitted by species of the B. tabaci species complex. The transmission of viruses belonging to two of these, Begomovirus and Crinivirus, are well studied and much is known in regards to the relationship between species and transmission and etiology. This is in contrast to viruses of the genera, Torradovirus and Carlavirus, for which very little is known inregards to their transmission. This is the first attempt to integrate viral data within the new B. tabaci species complex framework. It is clear that matching historical transmission data with the current species framework is difficult due to the lack of awareness of the underlying genetic diversity within B. tabaci. We encourage all researchers to determine which species of B. tabaci they are using to facilitate association of phenotypic traits with particular members of the complex. © 2014 Society of Chemical Industry

BACKGROUND Bemisia tabaci is a cryptic species complex. In Pakistan, members of the complex, MEAM1 and AsiaII 1, are the predominant species infesting cotton. The biology of the two on cotton, collard, cucumber and tomato was studied. RESULTS In all cases there were significant interactions between species and host. MEAM1 developmental periods did not differ significantly across hosts, whereas AsiaII 1 developed more slowly on vegetables than on cotton. MEAM1 survival was highest on tomato (53.5 ± 1.1%), while AsiaII 1 survived best on cotton (67.3 ± 11.6%). MEAM1 longevity and fecundity were highest on tomato (14.7 ± 1.7 days and 82.4 ± 9.9 eggs), while AsiaII 1 longevity and fecundity were highest on cotton (23.7 ± 2.5 days and 135.2 ± 13.6 eggs). The MEAM1 intrinsic rates of increase (rm) on cotton and vegetable were similar (0.08–0.10), whereas the AsiaII 1 rm on cotton (0.15) was higher than on vegetables (0.11–0.13). The biology of MEAM1 from Pakistan was compared with published studies; it had a consistently slower rate of development, lower percentage survival, lower adult longevity, longer generation time, lower net reproductive rate and lower rm. CONCLUSIONS MEAM1 performed similarly across all hosts, whereas AsiaII 1 performed better on cotton. The comparison between the Pakistani MEAM1 with published studies suggests that the invasive MEAM1 may have higher performance. © 2013 Society of Chemical Industry

The aphelinid parasitoid Eretmocerus hayati ZolnerowichRose (Hymenoptera: Aphelinidae) was recently released in Australia as a biocontrol agent against the crop pest Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). It was found that the parasitoid can spread over several kilometers in a single generation and continue laying eggs for over a fortnight. A simple wind-advection model was fitted to emergence data from a first release between Fassifern and Kalbar, Queensland, and its predictive ability was tested against the second release near Carnarvon, Western Australia. The fitting of the model was used to develop several hypotheses about the dispersal of E. hayati, which were validated by the second release: E. hayati flies in the same direction as the wind to a distance proportional to the wind speed; this wind-borne flight takes place at any time during daylight hours; a flight is attempted every day after emergence unless there are high wind conditions during that day; and the high wind condition that will delay flight is wind speeds in excess of ≍2 m/s. This model of E. hayati dispersal may be contrasted with previous models fitted for Eretmocerus species, for which dispersal was dominated by diffusion processes, and parasitoid spread was constrained to the scales of tens and hundreds of meters.

While Australia has lifted its outright ban on banana imports, very strict pre-entry requirements remain in place making it prohibitively expensive for foreign suppliers to land product in Australia. These include the establishment and maintenance of areas of low pest prevalence (following guidelines described in FAO, 2005; FAO, 2007, respectively), trash minimization procedures and post-harvest fungicide treatments (Biosecurity Australia, 2008). Strict though these import requirements are and small the risk of exotic disease transference may be, the potential consequences of some disease outbreaks to the Australian banana industry is potentially huge. In this paper we provide quantitative estimates of these potential damages (in Australian dollars, A$) and discuss the implications for Australia's import risk assessment process using the example of black Sigatoka. In 2001 this disease was detected in the Tully region of Queensland, a major banana production region. The cause of the outbreak remains unknown (Molina et al., 2005), but it was detected early enough to be eradicated at a cost A$17 million (Sosnowski et al., 2009). This outbreak has failed to quell calls to relax banana import requirements further, and criticism continues to be directed at Australia's import risk assessment process and its associated appropriate level of protection (Javelosa and Schmitz, 2006; Leroux and Maclaren, 2011). This is a locus of disease arrival probabilities and outbreak consequences with a unique product which forms a maximum expected damage a product entering the country can pose before violating Australian quarantine regulations. However, in practice the appropriate level of protection is not stated in quantitative terms, but is instead defined in rather ambiguous qualitative terms as very low. Our analysis provides quantitative evidence suggesting that in the case of banana imports, the appropriate level of protection corresponds to an expected damage of A$60 million per annum. This suggests that although current quarantine regulations are trade-restrictive, the appropriate level of protection corresponds to a relatively severe level of damage. (C) 2013 Elsevier Ltd. All rights reserved.

The differences in the ability of the invading whitefly, Bemisia tabaci (Gennadius) (commonly known as biotype B and hereafter as B) and Trialeurodes vaporariorum (Westwood) (both Hemiptera: Aleyrodidae) to utilize salivary phenol-oxidizing enzymes – polyphenol oxidase (PPO) and peroxidase (POD) to detoxify plant defensive phenolic compounds were explored. Polyphenol oxidase and POD were found in the saliva of both B and T. vaporariorum. For tomato colonies, the PPO and POD activities in the watery saliva of B were 2.27- and 1.34-fold higher than those of T. vaporariorum. The PPO activities against specific phenolic compounds commonly found in plants were compared. The activities of those from B were significantly greater than those from T. vaporariorum. We also measured PPO activity in both species after they had fed on plants that were undamaged or had been previously damaged with either a plant pathogen [Phytophthora infestans (Mont.) de Bary (Peronosporales)] infection, mechanical damage, B infestation, or exogenous salicylic acid. For B, PPO activities in watery saliva increased 229, 184, 152, and 139% in response to the four treatments, whereas those of T. vaporariorum only increased 133, 119, 113, and 103%, respectively. Biotype B infestation significantly increased the total phenolic content of tomato leaves. Meanwhile, feeding on tomato infestation with B had no significant effect on the survival rate of B, but decreased the survival rate of T. vaporariorum significantly. These results suggest that B has stronger ability utilizing PPO to detoxify high concentrations of phenolics than T. vaporariorum, and this contributes to a significant advantage for B to hold high fitness on plants with induced resistance. Possible roles of salivary PPO in the competition between B and T. vaporariorum are discussed.

The whitefly Bemisia tabaci complex harbours over 40 cryptic species that have been placed in 11 phylogenetically distinct clades based on the molecular characterization of partial mitochondrial DNA COI (mtCOI) gene region. Four cryptic species are currently within the invasive clade, i.e. MED, MEAM1, MEAM2 and IO. Correct identification of these species is a critical step towards implementing reliable measures for plant biosecurity and border protection; however, no standardized B. tabaci-specific primers are currently available which has caused inconsistencies in the species identification processes.We report three sets of polymerase chain reaction (PCR) primers developed to amplify the mtCOI region which can be used for genotyping MED, MEAM1 and IO species, and tested these primers on 91 MED, 35 MEAM1 and five IO individuals. PCR and sequencing of amplicons identified a total of 21, six and one haplotypes in MED, MEAM1 and IO respectively, of which six haplotypes were new to the B. tabaci database.These primer pairs enabled standardization and robust molecular species identification via mtCOI screening of the targeted invasive cryptic species and will improve quarantine decisions. Use of this diagnostic tool could be extended to other species within the complex. © 2017 Society of Chemical Industry.

Invasive species present significant threats to global agriculture, although how the magnitude and distribution of the threats vary between countries and regions remains unclear. Here, we present an analysis of almost 1,300 known invasive insect pests and pathogens, calculating the total potential cost of these species invading each of 124 countries of the world, as well as determining which countries present the greatest threat to the rest of the world given their trading partners and incumbent pool of invasive species. We find that countries vary in terms of potential threat from invasive species and also their role as potential sources, with apparently similar countries sometimes varying markedly depending on specifics of agricultural commodities and trade patterns. Overall, the biggest agricultural producers (China and the United States) could experience the greatest absolute cost from further species invasions. However, developing countries, in particular, Sub-Saharan African countries, appear most vulnerable in relative terms. Furthermore, China and the United States represent the greatest potential sources of invasive species for the rest of the world. The analysis reveals considerable scope for ongoing redistribution of known invasive pests and highlights the need for international cooperation to slow their spread.

Background In an effort to eliminate dengue, a successful technology was developed with the stable introduction of the obligate intracellular bacteria Wolbachia pipientis into the mosquito Aedes aegypti to reduce its ability to transmit dengue fever due to life shortening and inhibition of viral replication effects. An analysis of risk was required before considering release of the modified mosquito into the environment. Methods Expert knowledge and a risk assessment framework were used to identify risk associated with the release of the modified mosquito. Individual and group expert elicitation was performed to identify potential hazards. A Bayesian network (BN) was developed to capture the relationship between hazards and the likelihood of events occurring. Risk was calculated from the expert likelihood estimates populating the BN and the consequence estimates elicited from experts. Results The risk model for “Don’t Achieve Release” provided an estimated 46% likelihood that the release would not occur by a nominated time but generated an overall risk rating of very low. The ability to obtain compliance had the greatest influence on the likelihood of release occurring. The risk model for “Cause More Harm” provided a 12.5% likelihood that more harm would result from the release, but the overall risk was considered negligible. The efficacy of mosquito management had the most influence, with the perception that the threat of dengue fever had been eliminated, resulting in less household mosquito control, and was scored as the highest ranked individual hazard (albeit low risk). Conclusions The risk analysis was designed to incorporate the interacting complexity of hazards that may affect the release of the technology into the environment. The risk analysis was a small, but important, implementation phase in the success of this innovative research introducing a new technology to combat dengue transmission in the environment.

After the invasion of Australia by the Bemisia tabaci species Middle East-Asia Minor 1 (MEAM1, commonly known as the B biotype), the native parasitoid Eretmocerus mundus (Australian parthenogenetic form) was found to be an ineffective control agent. Eretmocerus hayati was therefore introduced and has substantially improved the level of control. A laboratory study was under taken to determine whether superior life history traits were one explanation for the better performance of E. hayati. We compared adult longevity, daily fecundity and proportion of female progeny of both mated and unmated females. We also compared the traits across females that were either treated with or without the antibiotic rifampicin, an antibiotic that had already been shown to deplete Wolbachia and enable E. mundus to produce males. We found that E. hayati adults survived longer and produced more progeny than E. mundus. Unmated E. hayati females produced only males. Rifampcin had no effect on any of the traits for E. hayati. In contrast, without rifampicin E. mundus females produced mostly female progeny whereas treated females produced mostly males. Recent studies suggest that E. hayati co-evolved with MEAM1, whereas the E. mundus in Australia co-evolved with the entirely distinct Asia members of the complex. This suggests that the underlying evolutionary relationships within the B. tabaci complex may be an important consideration when selecting agents for biological control.

The worldwide distribution and extensive genetic diversity of the whitefly, Bemisia tabaci, has long been recognized. However, the levels of separation within B. tabaci and the nomenclature of the various genetic groups have been a subject of debate. Recent phylogenetic analyses indicate that B. tabaci is a complex composed of >28 morphologically indistinguishable species. In this article, we first review the debate and difficulties associated with B. tabaci's taxonomy and systematics, and argue for the need to apply the biological species concept in order to elucidate B. tabaci's systematics. We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B. tabaci. Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs, and observations on mating behaviour have been conducted for seven species pairs. Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species. We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility. Finally, we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B. tabaci groups and propose future research directions on the systematics of this complex.

Since 2007 we have began to consider the relationships between the different members of the Bemisia tabaci species complex in a more structured and systematic way. Much of these relationships has been infered from considerations of a portion of the mitochondrial cytochrome oxidase one (mtCOI) gene. While this is a quite limited approach which would benefit from the consideration of a much greater diversity of genetic material, it is the only publically available data that spans the diversity of the species complex. Despite the limitations, the phylogenetic reconstruction that can be derived from this data is useful and can be used as a basis to frame questions and construct testable hypotheses that will form the basis for future research. This study uses the largest available mtCOI dataset, consisting of 383 unique mtCOI haplotypes that spans the full diversity of the B. tabaci species complex as we currently know it, to make a range of observations which are then used to develop questions as guide for future research.

Predation or parasitism on species introduced as biological control agents is a common explanation for failure of biological control programs. Although there is clear evidence from some biological control programs that hyperparasitism can impact a parasitoid biological control agent, it is not clear whether hyperparasitoids have the potential to cause control failure. We performed glasshouse experiments using cages containing 48 plants to address whether the hyperparasitoid Asaphes suspensus can potentially eliminate a population of the primary parasitoid Aphidius ervi, a biological control agent of the pea aphid Acyrthosiphon pisum. Although As. suspensus has a low intrinsic rate of increase, only one-half that of A. ervi and one-third that of pea aphids, it was nonetheless capable of eliminating the A. ervi population within seven A. ervi generations. In contrast, in the absence of As. suspensus, A. ervi eliminated the pea aphid population. Field surveys, however, found that As. suspensus does not eliminate entire natural populations of A. ervi in lucerne crops, probably due to the high frequency of disturbance that favours high intrinsic rates of increase and short generation times. Nonetheless, the ability of As. suspensus to eliminate A. ervi in cages despite its low intrinsic rate of increase underscores the potential for hyperparasitism to disrupt biological control. Small populations are expected to be particularly susceptible to hyperparasitism, such as when releases of a new biological control agent are made.

In 2010 a proposal to release the yellow fever mosquito, Aedes aegypti, containing an intracellular symbiotic bacterium, Wolbachia, as a means of reducing the severity of outbreaks of dengue fever was lodged in Australia. The mosquito was infected with Wolbachia through embryonic microinjection. This proposal uncovered a gap in the regulatory process normally used to assess the release of species into Australia. Firstly, while the association between the mosquito and the bacterium was new, both species naturally occurred in Australia and so legislation governing the introduction of new species into Australia was ruled not relevant. Secondly, the infection of the mosquito with Wolbachia did not involve gene technology and so was not subject to legislation governing the approval of genetically modified organisms. The solution came through the decision to use existing legislation to regulate Wolbachia as a veterinary chemical product. This was a good outcome as it overcame the barrier that a lack of regulatory oversight may have posed to field trials taking place. Furthermore, the approach taken demonstrated a very high level of scrutiny with regard to biosafety. This case is an example of how science is leading to advances that outstrip existing regulatory frameworks. An acceptable regulatory solution has been found, but the novelty of the science is such that the appropriateness of the regulatory process now needs to be reviewed to ensure that it is no more onerous for both the proponents and the regulators than it needs to be.

Bemisia tabaci has long been considered a complex species. It rose to global prominence in the 1980s owing to the global invasion by the commonly named B biotype. Since then, the concomitant eruption of a group of plant viruses known as begomoviruses has created considerable management problems in many countries. However, an enduring set of questions remains: Is B. tabaci a complex species or a species complex, what are Bemisia biotypes, and how did all the genetic variability arise? This review considers these issues and concludes that there is now sufficient evidence to state that B. tabaci is not made up of biotypes and that the use of biotype in this context is erroneous and misleading. Instead, B. tabaci is a complex of 11 well-defined high-level groups containing at least 24 morphologically indistinguishable species.

Pest risk maps are powerful visual communication tools to describe where invasive alien species might arrive, establish, spread, or cause harmful impacts. These maps inform strategic and tactical pest management decisions, such as potential restrictions on international trade or the design of pest surveys and domestic quarantines. Diverse methods are available to create pest risk maps, and can potentially yield different depictions of risk for the same species. Inherent uncertainties about the biology of the invader, future climate conditions, and species interactions further complicate map interpretation. If multiple maps are available, risk managers must choose how to incorporate the various representations of risk into their decisionmaking process, and may make significant errors if they misunderstand what each map portrays. This article describes the need for pest risk maps, compares pest risk mapping methods, and recommends future research to improve such important decision-support tools.

Summary 1. Predicting which species are more likely to invade a region presents significant difficulties to researchers and government agencies. Methods for estimating the risk of establishment are often qualitative and rely on consultation with experts and stakeholders. The inherent subjectivity of this process can lead to ambiguities in any estimate of a species’ risk of establishment. 2. Using global presence ⁄ absence data of insect crop pests employed a self-organizing map (SOM) to categorize regions based on similarities in species assemblages. This technique enabled them to generate a list of species and rank them based on an index of the risk of establishment. However, the sensitivity of this risk list to errors in the presence ⁄ absence data has never been tested. 3. We evaluated the sensitivity of the SOM method by altering the original presence ⁄ absence data by increasing amounts and compared estimates of risk with those generated by a national coordinating body (Plant Health Australia) utilizing expert stakeholder opinion. 4. The risk list was unaffected by alterations of up to 20% of data over all regions. The error rate we detected in the data was within these limits. 5. Comparison with the expert stakeholder methodology revealed significant differences in the estimates of establishment risk. Further analysis of the Australian data revealed that a number of regions with strong trade links to Australia supported species assemblages similar to those in Australia, suggesting they are possible sources of pest species with high probability of establishment. 6. Synthesis and applications. This analysis confirms that the SOM methodology is a robust tool in the quantification of risk of establishment. In addition, SOMs can deliver a level of objectivity, which can complement current consultative processes employed by many biosecurity agencies around the world, providing a better overall assessment of invasion risk. This assessment can inform research and development funding decisions and incursion management plans for both government and host industries. While SOMs are utilized in this work for the prioritization of pest insects they can potentially be applied to any taxa (pest or native) or at any scale in which the data are available.

Establishment failure by immigrant species, while believed to be a common occurrence, is difficult to observe and so factors contributing to failure are poorly explored. Human mediated disturbance is a key element in facilitating biological invasions, but its role in preventing establishment is rarely considered. In Australia, the whitefly, Bemisia tabaci biotype B was first detected in 1994 and has since spread widely and displaced an indigenous competitor. However, in one location it has failed to establish permitting an indigenous competitor to persist. In this area, the dominant plant host is Euphorbia cyathophora. Through a combination of laboratory and field experimentation we show that while both can utilise the young, upper leaves only the indigenous competitor can use the older lower leaves. We then demonstrate that the removal of the upper leaves as part of foreshore vegetation management is the key factor in preventing the establishment of the invader and subsequent displacement of its competitor. While human mediated disturbance coupled with complex biological interactions may promote invasion they may equally well retard rather than facilitate invasion, a factor that appears to have been largely ignored. Complexities of this kind must be conceived in our thinking to achieve a comprehensive understanding of biological invasion.

While competition for resources leading to invasion success is well recognized, avoidance of competition is much less so. Changes in behaviour that lead to avoidance are usually displayed by the weaker competitor. In our case though it was the stronger competitor that changed its behaviour by choosing a host for oviposition that was unacceptable to its competitor and avoiding one that was mutually acceptable; this accelerated the displacement of the competitor. We showed this by enclosing both invader (Middle East Asia Minor 1, B biotype) and indigenous (Australia, AN biotype) members of Bemisia tabaci species complex (sap sucking insects known as whiteflies) into field cages with either two plants that were a mutually acceptable oviposition host or one host that was acceptable to both and the other acceptable to the invader only. When only the mutually acceptable host was available, invader and indigenous females oviposited equally across the two plants. However, when given the choice, adult invaders still distributed themselves evenly across both hosts, but shifted their oviposition away from the mutually acceptable host and instead laid mostly on the host poorly utilized by the indigenous competitor. This indicates that the invader can change ovipositional choice to escape into competition free space.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a species complex that is one of the most devastating agricultural pests worldwide and affects a broad range of food, fiber and ornamental crops. Unfortunately, using parsimony and neighbor joining methods, global phylogenetic relationships of the major races/biotypes of B. tabaci remain unresolved. Aside from the limitations of these methods, phylogenetic analyses have been limited to only small subsets of the global collection of B. tabaci, and thus limited taxon sampling has confounded the analyses. To improve our understanding of global B. tabaci phylogenetic relationships, a Bayesian phylogenetic technique was utilized to elucidate the relationships among all COI DNA sequence data available in GenBank for B. tabaci worldwide (366 specimens). As a result, the first well-resolved phylogeny for the B. tabaci species complex was produced showing 12 major well-resolved (0.70 posterior probability or above) genetic groups: B. tabaci (Mediterranean/Asia Minor/Africa), B. tabaci (Mediterranean), B. tabaci (Indian Ocean), B. tabaci (sub-Saharan Africa silverleafing), B. tabaci (Asia I), B. tabaci (Australia), B. tabaci (China), B. tabaci (Asia II), B. tabaci (Italy), B. tabaci (New World), B. tabaci (sub-Saharan Africa non-silverleafing) and B. tabaci (Uganda sweet potato). Further analysis of this phylogeny shows a close relationship of the New World B. tabaci with Asian biotypes, and characteristics of the major sub-Saharan Africa non-silverleafing clade strongly supports an African origin of B. tabaci due to its position at the base of the global phylogeny, and the diversity of well-resolved sub-clades within this group. Bayesian re-analyses of B. tabaci ITS, COI, and a combined dataset from a previous study resulted in seven major well-resolved races with high posterior probabilities, also showing the utility of the Bayesian method. Relationships of the 12 major B. tabaci genetic groups are discussed herein.

The host instar preferences of Encarsia bimaculata and Eretmocerus sp. nr. furuhashii parasitizing Bemisia tabaci and their development on four host plants, collard, eggplant, cucumber and tomato, were studied in the laboratory. Both of the parasitoids accepted all nymphal stages of B. tabaci, but E. bimaculata preferred third and fourth instars while Er. sp. nr. furuhashii preferred second and third instars under both choice and no choice conditions. Regardless of host stage parasitized, adults of parasitoids emerged only from fourth instars. When given the simultaneous choice of all instars, E. bimaculata reduced parasitization of first and second instars (3.73 and 4.76%, respectively) while increasing parasitization of third and fourth instars (5.44 and 6.93%, respectively), in contrast Er. sp. nr. furuhashii increased its parasitization of second and third instar nymphs (1.27 and 3.17%, respectively) and decreased that of first and fourth instars (7.0 and 3.06%, respectively). Host plants did...

Quantifying the impact of alien invasive species on ecosystem services is an essential step in developing effective practices and policy for invasive species management. Here we develop a stochastic bioeconomic model that enables the economic impact of an invasive pest to be estimated before its arrival, based on relatively poorly specified ecological and economic parameters. We developed the model by using a hypothetical invasion of the varroa bee mite (Varroa destructor) into Australia and the negative flow-on effects that it would have on pollination by reducing honey bee populations, giving rise to a loss of pollination services, reduced crop yields, and additional production costs. If the mite were to continue to be prevented from entering the country over the next 30 years, we estimate that the economic costs avoided would be U.S. $16.4-38.8 million (Aus $21.3-50.5 million) per year. We suggest that current invasion response funding arrangements in Australia, which do not acknowledge these avoided damages, require amendment.

In this study, we investigated patterns of egg production and inclusion of bacterial endosymbionts in the whitesy Bemisia aff. gigantea Martin, a species native to lowland tropical rain forests of North Queensland, Australia. Development of the female reproductive system of B. aff. gigantea becomes evident in fourth instar/pharate adults, with extensive accumulation of mature (chorionated) eggs occurring 1Ð2 d before adult eclosion. Evidence from light and electron micros- copy indicates that bacteriocytes (specialized cells containing bacterial endosymbionts) appear scattered through the abdominal region in close association with the developing eggs. In pharate adults, bacteriocytes seem to enter developing eggs basally through the pedicel, and after oviposition they move distally from the pedicel as the embryo matures. In addition, developing ova without bacteriocytes were evident in 3-d-old females, indicating that oogenesis and bacteriocyte inclusion is an ongoing process. RESUMEDans cette etude, nous nous interessons ala production dOIufs et alOinclusion de bacteries endosymbiotiques de la mouche blancheBemisia aff.gigantea Martin, une espece originaire des plaines des forets tropicales du nord-est de lOAustralie. Le developpement du systeme reproducteur femelle de B. aff. gigantea appraoˆt au stade adulte pharate, avec une importante accumulation dOIufs matures se deroulant 1 a` 2 jours avant lOemergence de lOadulte. Des observations aux microscopes optique et electronique montrent que les bacteriocytes (cellules specialisees contenant les bacteries endosym- biotiques) sont disperses dans la region abdominale en relation etroite avec les Iufs en developpe- ment. Au quatrieme stade larvaire et au stade adulte, les bacteriocytes penetrent dans les Iufs en developpement par la base, au niveau du pedicelle. Apres lOoviposition, ils sOeloignent du pedicelle au fur et amesure que les embryons se developpent. De plus, des Iufs en developpement sans bacteriocytes sont presents chez des femelles de three jours, indiquant que lOoogenesis et lOinclusion de bacteriocytes sont des phenomenes continus.