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The insect crisis : the fall of the tiny empires that run the world
\"A devastating exploration of how the collapse in insect populations around the world threatens everything from wild birds to the food on our plate. From the ants scurrying under leaf litter to the bees able to fly higher than Mount Kilimanjaro, insects are seemingly everywhere. Three out of four of the planet's known species are insects, but a torrent of recent evidence suggests this kaleidoscopic group of creatures is suffering the greatest existential crisis in its remarkable 400-million-year history. Oliver Milman delves into why insect numbers are plummeting and outlines the dire consequences of losing the tiny empires that hold life aloft on Earth. Along the way, readers encounter a researcher who collects insect guts from the windshields of cars, the bees sent on long-haul truck journeys to prop up our food supply, and a desperate attempt to move trees up mountains to save an iconic butterfly. The mounting losses threaten to unpick the web of life we rely upon. Illuminating and inspiring, The Insect Crisis is a wake-up call for all of us\"-- Provided by publisher.
Book
Designing monitoring protocols to measure population trends of threatened insects: A case study of the cryptic, flightless grasshopper Brachaspis robustus
Designs and tests new population density and site occupancy monitoring protocols for the nationally endangered New Zealand flightless grasshopper Brachaspis robustus by comparing a) comprehensive plot and transect searches at one site and b) transect searches at two sites representing two different habitats (gravel road and natural riverbed) occupied by the species across its remaining range. Uses power analyses to determine a) the number of transects, b) the number of repeated visits and c) the grasshopper demographic to count to accurately detect long term change in relative population density. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
Journal Article
Mild Winter Causes Increased Mortality in the Fall Webworm Hyphantria cunea (Lepidoptera: Arctiidae)
The fall webworm Hyphantria cunea (Drury) is native to North America and Mexico and has currently expanded its distribution to the temperate areas of the Northern Hemisphere including Japan. According to the data on seasonal fluctuations of this moth for 18 years collected in western-central Japan, the abundance of adults of the overwintered generation showed a negative correlation with winter temperature. We investigated survival, weight loss, and fungal infection of diapausing pupae at 3.0 (an approximate temperature of cold winter) and 7.4 °C (a temperature of mild winter). In the results, mortality was higher and weight loss was larger in pupae exposed to 7.4 °C than in those exposed to 3.0 °C. In addition, pupae that were heavier at the start of cold exposure survived longer than lighter ones. Furthermore, almost all pupae that died at 7.4 °C were infected by fungi. It has been reported that the distribution range of this moth shifts to higher latitudes. According to the experiments conducted, it has been observed that warm winters can lead to a decrease in pupae weight and an increase in fungal deaths; however, the impact of warm winters on populations in the field can be more complicated and multifaceted.
Journal Article
Effect of seasonality on the population density of wetland aquatic insects: A case study of the Hawr Al Azim and Shadegan wetlands, Iran
Aim: Wetlands are extremely suitable ecosystems to assess the effect of climate change on the density of aquatic insects. This study aimed to assess the effect of seasonality on populations of aquatic insects in the Hawr Al Azim and Shadegan wetlands. Materials and Methods: The insect samplings were conducted at a large area of the Hawr Al Azim and five different sites of the Shadegan wetlands. In total, 18,534 arthropods of different life stages, including 12 orders containing 51 families, were collected and identified from the selected sites of the Shadegan and Hawr Al Azim wetlands. Results: Results showed that the population density of wetland aquatic insects gradually increased as the average daily temperature decreased, positively increased with daily mean relative humidity and precipitation, and decreased with the mean daily evaporation between October and April. Conversely, the population density of wetland aquatic insects gradually decreased with increasing average daily temperature and reduction of the mean relative humidity and precipitation and increasing the average evaporation from April to September. When differences between the average daily and water temperatures reached minimum in April, the population density of wetland aquatic insects reached maximum and turned mainly to families that they have high level of biological indices, indicating that wetlands have clean waters around the spring. While around the autumn conversely, they mostly changed to families that they have low level of biological indices, indicating that wetlands have unclean waters. Conclusion: The present study showed an optimum condition for the growth of insects around spring. Seasonality affects the population density of wetland aquatic insects during a year.
Journal Article
Insecticide resistance and its molecular basis in urban insect pests
Insecticide resistance is one of the most important evolutionary phenomena for researchers. Overuse of chemicals has induced resistance in insect pests that ultimately has led to the collapse of disease control programs in many countries. The erroneous and inappropriate management of insect vectors has resulted in dissemination of many vector-borne diseases like dengue, malaria, diarrhea, leishmaniasis, and many others. In most cases, the emergence of new diseases and the revival of old ones can be related with ecological changes that have favored rapid growth of vector densities. Understanding molecular mechanisms in resistant strains can assist in the development of management programs to control the development and spread of resistant insect populations. The dominant, recessive, and co-dominant forms of genes encoding resistance can be investigated, and furthermore, resistance development can be addressed either by the release of susceptible strains or timely insecticide rotation. The present review discusses the resistance level in all important insect vectors of human diseases; the molecular basis of evolvement of resistance has also been discussed.
Journal Article
Mangroves are an overlooked hotspot of insect diversity despite low plant diversity
Background
The world’s fast disappearing mangrove forests have low plant diversity and are often assumed to also have a species-poor insect fauna. We here compare the tropical arthropod fauna across a freshwater swamp and six different forest types (rain-, swamp, dry-coastal, urban, freshwater swamp, mangroves) based on 140,000 barcoded specimens belonging to
ca.
8500 species.
Results
We find that the globally imperiled habitat “mangroves” is an overlooked hotspot for insect diversity. Our study reveals a species-rich mangrove insect fauna (>3000 species in Singapore alone) that is distinct (>50% of species are mangrove-specific) and has high species turnover across Southeast and East Asia. For most habitats, plant diversity is a good predictor of insect diversity, but mangroves are an exception and compensate for a comparatively low number of phytophagous and fungivorous insect species by supporting an unusually rich community of predators whose larvae feed in the productive mudflats. For the remaining tropical habitats, the insect communities have diversity patterns that are largely congruent across guilds.
Conclusions
The discovery of such a sizeable and distinct insect fauna in a globally threatened habitat underlines how little is known about global insect biodiversity. We here show how such knowledge gaps can be closed quickly with new cost-effective NGS barcoding techniques.
Journal Article
Comparative resilience and precision of digitized optical counting using ImageJ during routine mosquito
Surveillance is integral for the targeted and effective function of integrated vector management. However, the scale of surveillance efforts can be prohibitive on manpower, given the large number of traps set, collected, processed, and enumerated. For many public health agencies, the sheer effort of weekly trapping, combined with the processing of numerous traps, is a major capacity challenge. To reduce employee fatigue and increase throughput, estimation methods are used in a diagnostic capacity to determine threshold numbers of mosquitoes (Diptera: Culicidae) for operational decision-making. Historically, volume and mass measures correlated to a known number of mosquitoes are the oldest and most widely used within mosquito control programs. Image processing methods using digital counting software, such as ImageJ, have not been tested rigorously in the context of high throughput usage experienced in mosquito operations. We stresstested volume, mass, and image processing methods using sample calibrations from early in the year and applied them throughout a mosquito active season. We additionally tested resilience with samples that had been frozen, desiccated, old, or from an excessively large trap collection. Furthermore, we compared magnitudes of error after intentionally deviating from best practices. In all cases, mass and volume encountered significant errors. In contrast, the digitized-optical counting method was resilient to going long periods of use without recalibrating, handling different species compositions, and processing aged or damaged samples. If a program has limited logistical power, the aforementioned image-processing method confers the best balance of accuracy and expediency for time-sensitive workloads and efficient operational decision making.
Journal Article
A Non-Invasive Method of Estimating Populations of ITomicus Piniperda/I on Scots Pine
Larger pine shoot beetle (Tomicus piniperda), which occupies a dominant position among secondary pests of Eurasian pine stands, is also a species whose activity leads to a number of favourable effects in relation to the functioning of ecosystems and broadly defined biodiversity. Thus it is necessary to have available an accurate, statistically based method for estimating its population. A fully non-invasive method for determining the numbers of T. piniperda can explain approximately 93% of the variation in the number of galleries in natural traps. The method may serve as a valuable supplement to existing methods used in the monitoring of T. pinierda populations. It may be used in nature reserves and in conservation-oriented forestry. The fully non-invasive method presented here can be used to evaluate Tomicus piniperda L. population sizes in areas subject to strict protection. Data were collected in 2021–2022 in forests containing P. sylvestris, with different stand structures, in the Suchedniowsko-Oblęgorski Landscape Park, Poland. Entomological analyses were carried out on natural traps made from live uncolonised trees. Stepwise regression was used to describe the size of T. piniperda populations. From a set of features representing stem colonisation parameters, stem traits and habitat, the following had a significant effect (p < 0.05) on the total number of galleries of T. piniperda on stems: (1) the number of T. piniperda maternal tunnels in the sixth stem section covering 2.5% of the total length, (2) the length of the stem section with bark thickness greater than 7 mm, and (3) stand structure (homogeneous Scots pine stands). The model can explain 93% (R[sub.adj] [sup.2] =0.9333) of the variability in the total number of T. piniperda galleries on trap trees. The mean relative error of estimation is 20.1%. The proposed method is particularly valuable in a climate context. The data obtained enable the prediction of the direct effects of climate change on the population dynamics of T. piniperda in natural forests.
Journal Article