39 results found
Aviles EI, Rotenberry RD, Collins CM, et al., 2020, Fluorescent markers rhodamine B and uranine for Anopheles gambiae adults and matings, Malaria Journal, Vol: 19, Pages: 1-9, ISSN: 1475-2875
BackgroundMarking mosquitoes is vital for mark-release-recapture and many laboratory studies, but their small size precludes the use of methods that are available for larger animals such as unique identifier tags and radio devices. Fluorescent dust is the most commonly used method to distinguish released individuals from the wild population. Numerous colours and combinations can be used, however, dust sometimes affects longevity and behaviour so alternatives that do not have these effects would contribute substantially. Rhodamine B has previously been demonstrated to be useful for marking adult Aedes aegypti males when added to the sugar meal. Unlike dust, this also marked the seminal fluid making it possible to detect matings by marked males in the spermatheca of females. Here, marking of Anopheles gambiae sensu stricto with rhodamine B and uranine was performed to estimate their potential contribution.MethodsTwo fluorescent markers, rhodamine B and uranine, were dissolved in sugar water and fed to adult An. gambiae. Concentrations that are useful for marking individuals and seminal fluid were determined. The effects on adult longevity, the durability of the marking and detection of the marker in mated females was determined. Male mating competitiveness was also evaluated.ResultsRhodamine B marking in adults is detectable for at least 3 weeks, however uranine marking declines with time and at low doses can be confused with auto-fluorescence. Both can be used for marking seminal fluid which can be detected in females mated by marked males, but, again, at low concentrations uranine-marking is more easily confused with the natural fluorescence of seminal fluid. Neither dye affected mating competitiveness.ConclusionsBoth markers tested could be useful for field and laboratory studies. Their use has substantial potential to contribute to a greater understanding of the bio-ecology of this important malaria vector. Rhodamine B has the advantage that it appears to be perma
Epopa PS, Millogo AA, Collins C, et al., 2020, Anopheles gambiae (s.l.) is found where few are looking: assessing mosquito diversity and density outside inhabited areas using diverse sampling methods, Parasites and Vectors, ISSN: 1756-3305
Hunt C, Collins C, Benedict MQ, 2020, Measuring and reducing biofilm in mosquito rearing containers, Parasites and Vectors, Vol: 13, ISSN: 1756-3305
BACKGROUND: Mosquito rearing containers contain organic-rich water that nourishes numerous bacteria, some of which are capable of forming biofilms. Biofilm is broadly an extracellular polymeric matrix (EPS) in which living bacteria occur, and the accumulation of biofilm is possible during routine stock-keeping as most of these containers are re-used. Whether biofilm has an effect on the mosquito rearing is not a question that has been investigated, nor have measures to reduce biofilm in this context been systematically studied. METHODS: We measured biofilm accumulation in standard rearing containers by staining with crystal violet and determining the OD using a spectrophotometer. We also treated rearing containers with 0.1% sodium hypochlorite to determine its effectiveness in reducing biofilm abundance. Lastly, we performed an analysis of the relationship between the occurrence of biofilm and the likelihood of microbial blooms that were associated with larval death during trials of larval diets. RESULTS: We observed that soaking rearing containers overnight in 0.1% sodium hypochlorite greatly reduced biofilm, but we observed no relationship between the use of containers that had not been treated with bleach and subsequent microbial blooms. CONCLUSIONS: Larva rearing leaves detectable biofilm. While we were unable to correlate microbial blooms with the presence of biofilm, as a precaution, we recommend that plastic containers that are re-used be treated with 0.1% sodium hypochlorite occasionally.
Fletcher EI, Collins C, 2020, Urban Agriculture: Declining opportunity and increasing demand. How observations from London, U.K., can inform effective response, strategy and policy on a wide scale, Urban Forestry and Urban Greening, ISSN: 1610-8167
Savolainen V, Clottey VA, Doubi Bi TS, et al., 2020, Systems thinking creates opportunities for a circular economy and sustainable palm agriculture in Africa, Current Research in Environmental Sustainability, Vol: 1, Pages: 31-34, ISSN: 2666-0490
Palm agriculture has received strong criticism in recent years due to its link with deforestation, especially in Asia. Here we propose that there is instead an opportunity for sustainable palm futures in Africa. Applying interdisciplinary systems thinking and circular production models, food and economic security can be achieved sustainably by (i) promoting integrated production of nutritionally valuable insect and fungal protein using palm crop waste; (ii) increasing resilience and productivity of crop palms in the harsh tropical climates of sub-Saharan Africa; and (iii) promoting the development of palm plantations as biodiverse agroforestry ecosystems.
Hunt C, Benedict MQ, Collins C, et al., Surviving the journey: Comparisons of temperature-stabilizing materials for living arthropod shipments, The Journal of the American Mosquito Control Association, ISSN: 8756-971X
Shipments of living mosquitoes and other arthropods require temperatures that are within a range that is compatible with their health and survival. In addition to express shipping and insulated containers, shipments often include materials that either store heat (i.e. have thermal mass) or otherwise stabilize the temperature. In this manuscript, we present the results of comparisons of thermal mass and phase change materials to stabilize the temperature under various conditions. We compared a rigid foam refrigerant and a number of phase change materials to bubble wrap for their capacity to moderate temperature change by measuring the temperatures in standard uninsulated shipping containers during exposure to high (37°C), cold (4°C) and freezing (-20°C) temperatures. We make recommendations for shipments depending on the ambient conditions that are expected to be experienced en route.
Collins CMT, Quinlan MM, 2020, Auditing preparedness for vector control field studies, The American Journal of Tropical Medicine and Hygiene, Vol: 102, Pages: 707-710, ISSN: 0002-9637
The value of baseline entomological data to any future area-wide release campaign relies on the application of consistent methods to produce results comparable across different times and places in a stepwise progression to larger releases. Traditionally, standard operating procedures (SOPs) and operational plans support this consistency and, thus, the validity of emergent data. When release plans include transgenic mosquitoes for vector control or other novel beneficial insects, additional factors come into play such as biosafety permits, stakeholder acceptance, and ethics approval, which require even greater coordination and thoroughness. An audit approach was developed to verify the correct use of SOPs and appropriate performance of tasks during mosquito mark, release, recapture (MRR) studies. Audit questions matched SOPs, permit terms and conditions, and other key criteria, and can be used to support subsequent “spot check” verification by field teams. An external team of auditors, however, was found to be effective for initial checks in this example before the use of a transgenic strain of laboratory mosquitoes. We recommend similar approaches for field studies using release of novel beneficial insects, to ensure useful and valid data as an outcome and to support confidence in the rigor of the step-wise process.
Benedict MQ, Hunt CM, Vella MG, et al., 2020, Pragmatic selection of larval mosquito diets for insectary rearing of Anopheles gambiae and Aedes aegypti, PLoS One, Vol: 15, ISSN: 1932-6203
Larval mosquitoes are aquatic omnivorous scavengers which scrape food from submerged surfaces and collect suspended food particles with their mouth brushes. The composition of diets that have been used in insectaries varies widely though necessarily provides sufficient nutrition to allow colonies to be maintained. Issues such as cost, availability and experience influence which diet is selected. One component of larval diets, essential fatty acids, appears to be necessary for normal flight though deficiencies may not be evident in laboratory cages and are likely more important when mosquitoes are reared for release into the field in e.g. mark-release-recapture and genetic control activities. In this study, four diets were compared for rearing Anopheles gambiae and Aedes aegypti, all of which provide these essential fatty acids. Two diets were custom formulations specifically designed for mosquitoes (Damiens) and two were commercially available fish foods: Doctors Foster and Smith Koi Staple Diet and TetraMin Plus Flakes. Development rate, survival, dry weight and adult longevity of mosquitoes reared with these four diets were measured. The method of presentation of one diet, Koi pellets, was additionally fed in two forms, pellets or a slurry, to determine any effect of food presentation on survival and development rate. While various criteria might be selected to choose 'the best' food, the readily-available Koi pellets resulted in development rates and adult longevity equal to the other diets, high survival to the adult stage and, additionally, this is available at low cost.
Didham RK, Barbero F, Collins CM, et al., 2020, Spotlight on insects: trends, threats and conservation challenges, Insect Conservation and Diversity, Vol: 13, Pages: 99-102, ISSN: 1752-458X
There is mounting concern over the conservation status and long‐term trends in insect populations. Many insect populations have been reported to be falling and many species are threatened with extinction. While this is true, the evidence does not support unqualified statements of ‘global insect decline’. Global environmental change does not affect all species equally, and there are clear winners as well as losers from anthropogenic impacts.In this special issue of Insect Conservation and Diversity, we draw together articles that (i) identify key challenges in robust inference about insect population trends, (ii) present new empirical evidence for declines (and increases) in insect populations, spanning whole communities down to single species, in both aquatic and terrestrial ecosystems, and (iii) address the interacting drivers of population change, from empirical studies of environmental correlates, to experimental manipulation of driving mechanisms.We argue that the way forward for insect conservation includes more nuanced language and approaches when communicating ecological evidence to peer and public audiences, beyond just a simplistic focus on the insect decline narrative. This will require an expanded portfolio of approaches to promote the value of insects to society, which in turn, should reinforce the social licence to prioritise insect conservation research. This should help us to deliver the rigorous science necessary to document ongoing trends and understand the drivers and mechanisms of population change. Only then will we be able to mitigate or reverse declining populations.
Didham RK, Basset Y, Collins CM, et al., 2020, Interpreting insect declines: seven challenges and a way forward, Insect Conservation and Diversity, Vol: 13, Pages: 103-114, ISSN: 1752-458X
Many insect species are under threat from the anthropogenic drivers of global change. There have been numerous well‐documented examples of insect population declines and extinctions in the scientific literature, but recent weaker studies making extreme claims of a global crisis have drawn widespread media coverage and brought unprecedented public attention. This spotlight might be a double‐edged sword if the veracity of alarmist insect decline statements do not stand up to close scrutiny.We identify seven key challenges in drawing robust inference about insect population declines: establishment of the historical baseline, representativeness of site selection, robustness of time series trend estimation, mitigation of detection bias effects, and ability to account for potential artefacts of density dependence, phenological shifts and scale‐dependence in extrapolation from sample abundance to population‐level inference.Insect population fluctuations are complex. Greater care is needed when evaluating evidence for population trends and in identifying drivers of those trends. We present guidelines for best‐practise approaches that avoid methodological errors, mitigate potential biases and produce more robust analyses of time series trends.Despite many existing challenges and pitfalls, we present a forward‐looking prospectus for the future of insect population monitoring, highlighting opportunities for more creative exploitation of existing baseline data, technological advances in sampling and novel computational approaches. Entomologists cannot tackle these challenges alone, and it is only through collaboration with citizen scientists, other research scientists in many disciplines, and data analysts that the next generation of researchers will bridge the gap between little bugs and big data.
Hunt CM, Benedict MQ, Collins CM, et al., 2019, COMPARISONS OF TEMPERATURE-STABILIZING MATERIALS FOR LIVING ARTHROPOD SHIPMENTS, 68th Annual Meeting of the American-Society-for-Tropical-Medicine-and-Hygiene (ASTMH)
Collins C, Vaskou P, Kountouris I, 2019, Insect food products in the Western world: assessing the potential of a new ‘green’ market, Annals of the Entomological Society of America, Vol: 112, Pages: 518-528, ISSN: 0013-8746
Although two billion people already eat insects in the world and the benefits of edible insects are well known, these ‘green’ sources of protein are neither treated as conventional food products nor widely incorporatedinto Western diets. Using a school-based investigation surveying 161 children, aged 6–15, and 114 of theirparents in London, and an online consumer survey with mainly British and French consumers (N = 1,020), this research provides insights into the potential of the insect market in the West. This work supports the idea that incorporating insect food into our diets makes not only environmental but also business sense.A nonnegligible segment of the population surveyed is willing to pay for mealworm minced meat and young children and pre-teens could represent a substantial market segment, as yet unexplored. This analysis points to multiple marketing strategies, such as early exposure, education, reducing the visibility of insect parts, celebrity endorsement, or peer-to-peer marketing, all of which could facilitate the adoption of insect food in the ‘mainstream’ arena, according to the consumer segment being targeted. Generalizations from these results are restricted to an educated and youthful subset of the potential consumer pool and further work remains to understand the patterns of Western consumer acceptance for the range of insect foods.
McDade H, Collins C, 2019, How might we overcome ‘Western’ resistance to eating insects?, Edible Insects, Editors: Mikkola, Publisher: IntechOpen, ISBN: 978-1-78985-636-1
Entomophagy, the consumption of insects as a food source, occurs at a global scale with over 2 billion people seeing it as traditional. This practice does not extend into mainstream Western culture where its introduction is often met by a range of barriers, leaving entomophagy often seen as a taboo. The ‘disgust response’ of food neophobia and a lack of social and cultural contexts that reduce adoption may be overcome by strategic application of tools arising from innovation diffusion theory: relative advantage; compatibility; low complexity; trialability and observability. This chapter accessibly reviews known barriers to uptake and outlines the potential application of these concepts in promoting the wider acceptance of entomophagy.
Dickie F, Miyamoto M, Collins CM, 2019, The potential of insect farming to increase food security, Edible Insects, Editors: Mikkola, Publisher: Intech Open, ISBN: 978-1-78985-636-1
Insect protein production through ‘mini-livestock farming’ has enormouspotential to reduce the level of undernutrition in critical areas across the world. Sustainable insect farming could contribute substantially to increased food security, most especially in areas susceptible to environmental stochasticity. Entomophagyhas long been acknowledged as an underutilised strategy to address issues of food security. This chapter reviews and provides a synthesis of the literature surrounding the potential of insect farming to alleviate food security while promoting food sovereignty and integrating social acceptability. These are immediate and current problems of food security and nutrition that must be solved to meet the UNDP Sustainable Development Goals.
Benedict M, Hunt C, Vella M, et al., 2019, Pragmatic selection of larval mosquito diets for insectary rearing of Anopheles gambiae and Aedes aegypti, PLoS One
Abstract Larval mosquitoes are aquatic omnivorous scavengers which scrape food from submerged surfaces and collect suspended food particles with their mouth brushes. The composition of diets that have been used in insectaries varies widely though necessarily provides sufficient nutrition to allow colonies to be maintained. Issues such as cost, availability and experience influence which diet is selected. One component of larval diets, essential fatty acids, appears to be necessary for normal flight though deficiencies may not be evident in laboratory cages and are likely more important when mosquitoes are reared for release into the field in e.g. mark-release-recapture and genetic control activities. In this study, four diets were compared for rearing Anopheles gambiae and Aedes aegypti , all of which provide these essential fatty acids. Two diets were custom formulations specifically designed for mosquitoes (Damiens) and two were commercially available fish foods: Doctors Foster and Smith Koi Staple Diet and TetraMin Plus Flakes. Development rate, survival, dry weight and adult longevity of mosquitoes reared with these four diets were measured. The method of presentation of one diet, Koi pellets, was additionally fed in two forms, pellets or a slurry, to determine any effect of food presentation on survival and development rate. While various criteria might be selected to choose ‘the best’ food, the readily-available Koi pellets resulted in development rates and adult longevity equal to the other diets, high survival to the adult stage and, additionally, this is available at low cost.
Collins C, Cook-Monie I, Raum S, 2019, What do people know? Ecosystem services, public perception and sustainable management of urban park trees in London, U.K., Urban Forestry and Urban Greening, Vol: 43, ISSN: 1618-8667
Engagement with users and other public stakeholder groups is important when making planning and planting decisions for urban parks; it ensures the public feel involved and that decisions have longstanding support. Park trees provide an array of important ecosystem services but are threatened by pressures such as climate change, diseases and lack of management resources. It is important to ensure the public appreciate the breadth of services provided, and the challenges faced, by park trees. To evaluate the baseline public understanding of these issues, we surveyed 344 members of the public in London, U.K. parks to examine their perception of the importance of park trees and their understanding of the challenges they face. This exploratory study found that though the term ‘Ecosystem Service’ was largely unfamiliar, the public value park trees highly. Affluence and other demographic factors appear to have little influence on these perceptions, however, age and visit frequency slightly influenced the perceived importance of trees for their contribution to park aesthetics. Urbanisation and proximate human threats, especially pollution were considered by respondents the most important challenges facing park trees. Disease and climate change ranked 4th and 15th respectively, indicating that public education about the challenges facing park trees may be needed in advance of, or as part of plans for sustainable park management and plantings.
Epopa PS, Collins CM, North A, et al., 2019, Seasonal malaria vector and transmission dynamics in western Burkina Faso, Malaria Journal, Vol: 18, ISSN: 1475-2875
BackgroundIn the context of widespread mosquito resistance to currently available pesticides, novel, precise genetic vector control methods aimed at population suppression or trait replacement are a potentially powerful approach that could complement existing malaria elimination interventions. Such methods require knowledge of vector population composition, dynamics, behaviour and role in transmission. Here were characterized these parameters in three representative villages, Bana, Pala and Souroukoudingan, of the Sudano-Sahelian belt of Burkina Faso, a region where bed net campaigns have recently intensified.MethodsFrom July 2012 to November 2015, adult mosquitoes were collected monthly using pyrethroid spray catches (PSC) and human landing catches (HLC) in each village. Larval habitat prospections assessed breeding sites abundance at each site. Mosquitoes collected by PSC were identified morphologically, and then by molecular technique to species where required, to reveal the seasonal dynamics of local vectors. Monthly entomological inoculation rates (EIR) that reflect malaria transmission dynamics were estimated by combining the HLC data with mosquito sporozoite infection rates (SIR) identified through ELISA-CSP. Finally, population and EIR fluctuations were fit to locally-collected rainfall data to highlight the strong seasonal determinants of mosquito abundance and malaria transmission in this region.ResultsThe principal malaria vectors found were in the Anopheles gambiae complex. Mosquito abundance peaked during the rainy season, but there was variation in vector species composition between villages. Mean survey HLC and SIR were similar across villages and ranged from 18 to 48 mosquitoes/person/night and from 3.1 to 6.6% prevalence. The resulting monthly EIRs were extremely high during the rainy season (0.91–2.35 infectious bites/person/day) but decreased substantially in the dry season (0.03–0.22). Vector and malaria transmission dynamics generall
Collins CM, Bonds J, Quinlan M, et al., 2019, Effects of removal or reduced density of the malaria mosquito, Anopheles gambiae s.l., on interacting predators and competitors in local ecosystems, Medical and Veterinary Entomology, Vol: 33, Pages: 1-15, ISSN: 0269-283X
New genetic control methods for mosquitoes may reduce vector species without direct effects on other species or the physical environment common with insecticides or drainage. Effects on predators and competitors could, however, be a concern as Anopheles gambiae s.l. is preyed upon in all life stages. We overview the literature and assess the strength of the ecological interactions identified. Most predators identified consume many other insect species and there is no evidence that any species preys exclusively on any anopheline mosquito. There is one predatory species with a specialisation on blood‐fed mosquitoes including An. gambiae s.l.. Evarcha culicivora is a jumping spider, known as the vampire spider, found around Lake Victoria. There is no evidence that these salticids require Anopheles mosquitoes and will readily consume blood‐fed Culex. Interspecific competition studies focus on other mosquitoes of larval habitats. Many of these take place in artificial cosms and give contrasting results to semi‐field studies. This may limit their extrapolation regarding the potential impact of reduced An. gambiae numbers. Previous mosquito control interventions are informative and identify competitive release and niche opportunism; so while the identity and relative abundance of the species present may change, the biomass available to predators may not.
Facchinelli L, North AR, Collins CM, et al., 2019, Large-cage assessment of a transgenic sex-ratio distortion strain on populations of an African malaria vector, Parasites & Vectors, Vol: 12, ISSN: 1756-3305
BackgroundNovel transgenic mosquito control methods require progressively more realistic evaluation. The goal of this study was to determine the effect of a transgene that causes a male-bias sex ratio on Anopheles gambiae target populations in large insectary cages.MethodsLife history characteristics of Anopheles gambiae wild type and Ag(PMB)1 (aka gfp124L-2) transgenic mosquitoes, whose progeny are 95% male, were measured in order to parameterize predictive population models. Ag(PMB)1 males were then introduced at two ratios into large insectary cages containing target wild type populations with stable age distributions and densities. The predicted proportion of females and those observed in the large cages were compared. A related model was then used to predict effects of male releases on wild mosquitoes in a west African village.ResultsThe frequency of transgenic mosquitoes in target populations reached an average of 0.44 ± 0.02 and 0.56 ± 0.02 after 6 weeks in the 1:1 and in the 3:1 release ratio treatments (transgenic male:wild male) respectively. Transgenic males caused sex-ratio distortion of 73% and 80% males in the 1:1 and 3:1 treatments, respectively. The number of eggs laid in the transgenic treatments declined as the experiment progressed, with a steeper decline in the 3:1 than in the 1:1 releases. The results of the experiment are partially consistent with predictions of the model; effect size and variability did not conform to the model in two out of three trials, effect size was over-estimated by the model and variability was greater than anticipated, possibly because of sampling effects in restocking. The model estimating the effects of hypothetical releases on the mosquito population of a West African village demonstrated that releases could significantly reduce the number of females in the wild population. The interval of releases is not expected to have a strong effect.ConclusionsThe biological data produced to parameterize the model
Epopa PS, Millogo AA, Collins CM, et al., 2017, The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the Anopheles gambiae complex in Bana, a west African humid savannah village, Parasites & Vectors, Vol: 10, ISSN: 1756-3305
Background:Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village.Methods:Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407–5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling.Results:Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000–50,000) to the wet season (100,000–500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release loca
Ngiam RWJ, Lim WL, Collins CM, 2017, A balancing act in urban social-ecology: human appreciation, ponds and dragonflies, Urban Ecosystems, ISSN: 1573-1642
Green spaces in cities provide cultural ecosystem services (CES) such as nature connection, wildlife interaction and aesthetic appreciation which can improve aspects of human well-being. Recognising these benefits, researchers are now examining the complex relationship between humans and nature in urban social-ecology. Most studies investigate people’s appreciation and valuation of different green space features and their contribution to urban biodiversity.Recommendations arising from such studies are best practices to achieve a balance between landscape aesthetic and ecological objectives, but many knowledge gaps still exist. In asocial-ecological project in Greater London, appreciation of ponds and dragonflies in urban green spaces, and the environmental factors determining dragonfly diversity were investigated. We found ponds and their appearance were valued by people as enhancing their green space experience. The preference for wild-looking ponds was moderate. Dragonflies were enjoyed for their colour and high visibility, especially by those who had basic dragonfly knowledge. Species richness of dragonflies was positively associated with habitat heterogeneity in and around a pond. However, people were unable to relate a heterogeneous pond to more dragonfly species. For the first time, some factors that influence the human appreciation-ponds-dragonflies (HPD) relationship in an urban context are revealed. To fully realise the CES potential of ponds and dragon flies in Greater London, a HPD framework is proposed.The framework underpins strategies that foster cultural sustainability for ponds and dragonfly conservation.
Valerio L, North A, Collins CM, et al., 2016, Comparison of Model Predictions and Laboratory Observations of Transgene Frequencies in Continuously-Breeding Mosquito Populations., Insects, Vol: 7, ISSN: 2075-4450
The persistence of transgenes in the environment is a consideration in risk assessments of transgenic organisms. Combining mathematical models that predict the frequency of transgenes and experimental demonstrations can validate the model predictions, or can detect significant biological deviations that were neither apparent nor included as model parameters. In order to assess the correlation between predictions and observations, models were constructed to estimate the frequency of a transgene causing male sexual sterility in simulated populations of a malaria mosquito Anopheles gambiae that were seeded with transgenic females at various proportions. Concurrently, overlapping-generation laboratory populations similar to those being modeled were initialized with various starting transgene proportions, and the subsequent proportions of transgenic individuals in populations were determined weekly until the transgene disappeared. The specific transgene being tested contained a homing endonuclease gene expressed in testes, I-PpoI, that cleaves the ribosomal DNA and results in complete male sexual sterility with no effect on female fertility. The transgene was observed to disappear more rapidly than the model predicted in all cases. The period before ovipositions that contained no transgenic progeny ranged from as little as three weeks after cage initiation to as long as 11 weeks.
Valerio L, Collins CM, Lees RS, et al., 2016, Benchmarking vector arthropod culture: an example using the African malaria mosquito, Anopheles gambiae (Diptera: Culicidae), Malaria Journal, Vol: 15, ISSN: 1475-2875
BackgroundNumerous important characteristics of adult arthropods are related to their size; this is influenced by conditions experienced as immatures. Arthropods cultured in the laboratory for research, or mass-reared for novel control methods, must therefore be of a standard size range and known quality so that results are reproducible.MethodsA simple two-step technique to assess laboratory culture methods was demonstrated using the mosquito Anopheles gambiae s.s. as a model. First, the ranges of key development outcomes were determined using various diet levels. The observed outcomes described the physiologically constrained limits. Secondly, the same outcomes were measured when using a standard operating procedure (SOP) for comparison with the determined ranges.ResultsThe standard method resulted in similar development rates to those of high and medium diets, wing length between those resulting from the high and medium diets, and larval survival exceeding all benchmark diet level values. The SOP used to produce experimental material was shown to produces high-quality material, relative to the biologically constrained limits.ConclusionsThe comparison between all possible phenotypic outcomes, as determined by biological constraints, with those outcomes obtained using a given rearing protocol is termed “benchmarking”. A method is here demonstrated which could be easily adapted to other arthropods, to objectively assess important characters obtained, and methods used, during routine culture that may affect outcomes of research.
Facchinelli L, Valerio L, Lees RS, et al., 2015, Stimulating Anopheles gambiae swarms in the laboratory: application for behavioural and fitness studies, MALARIA JOURNAL, Vol: 14, ISSN: 1475-2875
Kanvil S, Collins CM, Powell G, et al., 2015, Cryptic Virulence and Avirulence Alleles Revealed by Controlled Sexual Recombination in Pea Aphids, GENETICS, Vol: 199, Pages: 581-593, ISSN: 0016-6731
Milcu A, Bonkowski M, Collins CM, et al., 2015, Aphid honeydew-induced changes in soil biota can cascade up to tree crown architecture, PEDOBIOLOGIA, Vol: 58, Pages: 119-127, ISSN: 0031-4056
Crossley R, Collins CM, Sutton SG, et al., 2014, Public perception and understanding of shark attack mitigation measures in Australia, Human Dimensions of Wildlife
Collins CM, Charles JG, Allegro G, et al., 2014, Insects and other pests of poplars and willows, Poplars and Willows: Trees for society and the environment, Editors: Isebrands, Richardson, Publisher: FAO & CABI, ISBN: 978-1-78064-108-9
Aqueel MA, Collins CM, Raza AM, et al., 2013, Effect of plant nutrition on aphid size, prey consumption and life history characteristics of green lacewing, Insect Science
Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea (S.) (Neuroptera: Chrysopidae) on the cereal aphids, Rhopalosiphum padi (L.) and Sitobion avenae (F.) at varying nitrogen fertilizer levels was calculated under laboratory conditions. Wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the C. carnea. Aphid densities of 10, 30 and 90 were offered to 1st, 2nd and 3rd instar larvae of green lacewing. Increased nitrogen application improved nitrogen contents of the plants and also the body weight of cereal aphids feeding on them. Aphid consumption by green lacewings was reduced with the increase in nitrogen content in the host plants of aphids. Predation of both aphid species by first, second and third instars larvae of C. carnea was highest on aphids reared on plants with the lowest rate of fertilization, suggesting a compensatory consumption to overcome reduced biomass (lower aphid size). Total biomass devoured by C. carnea on all nitrogen fertilizer treatments was not statistically different. Additionally, the heavier host prey influenced by the plant nutrition had an effect on the life history characteristics of green lacewings. The larval duration, pupal weight, pupal duration, fecundity and male and female longevity were significantly affected by the level of nitrogen fertilization to the aphid's host plants, except for pupal duration when fed on S. avenae. This study showed that quantity of prey supplied to the larvae affects the prey consumption and thereafter the life history characteristics of green lacewings.
Sharma MV, Collins CM, Leather SR, 2013, Anthropogenic influences on fruit crop in wild nutmeg from the Western Ghats of India, Journal of Sustainable Forestry, Vol: 3
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