Terrestrial Insects Research Articles

From insects to mammals! Tissue accumulation and transgenerational transfer of micro/nano-plastics through the food chain

Despite extensive global attention on microplastic pollution, our understanding of the pathways underlying microplastic translocation, accumulation, and their potential impacts on ecosystems and human health through the food chain remains incomplete. To investigate the translocation and accumulation of microplastics from insects to mammals, we developed a novel oral exposure model that Tenebrio molitor larvae (yellow mealworms, invertebrate terrestrial insects) were firstly orally exposed to both micro and nanometer-sized plastics (M/NPs), and subsequently fed as a food source to mice (mammals). Our results provide clear evidence that micro/nanoplastics (M/NPs) do indeed translocate through the food chain, from lower to higher trophic levels. Fluorescence microscopy and tissue quantification revealed the accumulation of M/NPs in the digestive, somatic, and circulatory systems of the larvae. Specifically, the food chain transferred M/NPs were later detected in the digestive, respiratory, and urinary systems of mice, showcasing strong fluorescent signals in vital organs such as the lungs, liver, intestines, brain, and kidneys, as well as in embryos. These findings highlight the intricate dynamics of M/NPs contamination, emphasizing their ability to traverse biological barriers, accumulate in organisms, and potentially impact embryonic development via food chain transfer.

30 years of terrestrial insect richness patterns across elevation: What have we learned? A global meta-analysis.

Understanding elevation variation in biodiversity is a classic question in ecology and has implications for understanding climate change impacts on mountain ecosystems. While insects are the largest group of animals, the global trend in insect species richness with elevation is unknown. To date, single studies and taxa-specific syntheses have provided no single picture, finding variable patterns of insect richness with elevation. A global synthesis across systems would provide a better understanding of how insect species richness changes with elevation and the possible environmental correlates of those patterns. We used published studies of terrestrial insect elevation gradients from 1990 to 2020 to ask: How do insect species richness change with elevation, and which environmental variables best explain this relationship statistically? With 1486 sites spanning 151 species richness-elevation gradients from 80 studies from four diverse insect taxonomic groups and five biomes, we found that overall proportional richness reached a low-elevation plateau and then decreased. We also show that mean annual temperature and seasonality best explain this trend. We suggest best practices and areas of interest for the future of insect richness-elevation studies, including underrepresented groups, geographic areas, and more standardized methods.

Insects decline with host plants but coextinctions may be limited

The loss of wild plant populations is often assumed to lead to coextinctions, particularly among specialized insects. Despite global declines in both terrestrial insects and plants, the relationship between these trends remains elusive. Here, we address this gap by analyzing the relationship between population trends of insects and their host plants in Germany, encompassing over 150,000 interactions among 3,429 plant and 2,239 insect species, including both pollinators (bees and hoverflies) and herbivores (butterflies, moths, and sawflies). Our findings reveal parallel population declines of insects and host plants across taxa, except for more generalist hoverflies. However, simulated extinctions of threatened host plants led to limited coextinctions in insects. Notably, 96% of insect species retained over 25% of their host plant diversity, and among those, 98% still retained at least one common species in their interaction portfolio. Even highly specialized insects may persist because they tend to specialize in nonthreatened plant species. While uncertainties remain regarding the interchangeability of host plants, our findings suggest that insect coextinctions are far from a 1:1 match with plant extinctions. Our findings suggest the declining abundance of many plant species can contribute to insect decline yet challenge the common assumption that the extinction of threatened plant species will necessarily trigger an imminent extinction wave of associated insects. Interaction networks seem to be more resilient.

Distinct food-web transfers of 137Cs to fish in river and lake ecosystems: A case study focusing on masu salmon in the Fukushima evacuation zone

This study was conducted to elucidate the spatial and size variations, and food-web transfer of 137Cs in freshwater fish in the upper reaches of the Ukedo River system, a highly contaminated river system flowing through the Fukushima evacuation zone. Fish collection and environmental surveys were conducted in the summer of 2020 at five forest rivers and at the Ogaki Dam reservoir (an artificial lake) with different air dose rates (mean 0.20–3.32 μSv/h). From the river sites, two salmonid species (masu salmon and white-spotted charr) were sampled, with masu salmon generally exhibiting higher 137Cs concentrations, ranging widely (10.6 Bq/kg-wet to 13.0 kBq/kg-wet) depending on the fish size (size effect) and site. The 137Cs concentrations in masu salmon were explained by the air dose rates, 137Cs concentrations in water, sediments (excluding the lake site), and primary producers, with site-specific variations. In the rivers, masu salmon (fluvial type with parr marks) mainly fed on terrestrial insects with higher 137Cs concentrations compared with those of aquatic insects, indicating that 137Cs was transferred mainly to fish through the allochthonous forest food-web during summer. In the lake, masu salmon (lake-run type with larger size and silvery body coloration) mainly preyed on smaller fish with lower 137Cs concentrations, demonstrating that 137Cs is transferred to fish through the autochthonous lake food-web with biomagnification. Differences in 137Cs concentrations among masu salmon (mean 441 Bq/kg-wet) and other fish species (mean 74.8 Bq/kg-wet to 2.35 kBq/kg-wet) were also found in the lake. The distinct 137Cs transfers to river and lake fish were supported by stable isotope analysis: δ15N and δ13C values enriched stepwisely through the food-webs were, respectively, higher and lower in the lake. Our results obtained using multiple approaches clearly revealed the distinct food-web transfer of 137Cs in river and lake ecosystems. These findings can contribute to prediction of radioactive contamination in freshwater fish in the Fukushima evacuation zone.

Biochemical profile of the native seaweed fly Fucellia maritima (Haliday, 1838) (Diptera: Anthomyiidae) reared on five different substrates

Abstract The sustainability of aquaculture production is crucial for the industry’s long-term viability. Diversification of feed ingredients is a key component in achieving this sustainability. Considered a promising alternative to traditional feed ingredients, terrestrial insect meals often lack sufficient n-3 polyunsaturated fatty acids (PUFA). This study explores the potential of marine insect species, specifically evaluating the influence of five different substrates on the growth and composition of the European native seaweed fly, Fucellia maritima. The substrates tested include a brown seaweed (Fucus sp.), a green seaweed (Ulva sp.), a red seaweed (the invasive Agarophyton vermiculophyllum), the invasive freshwater hyacinth (Eichhornia crassipes), and fish processing waste (codfish Gadus morhua frames). Results show no significant difference in the number of individuals per substrate, although Fucus sp. had a higher total number of individuals completing their life cycle. In contrast, feeding on codfish frames resulted in a lower number of completed life cycles, while E. crassipes led to no survival. Protein content in adult flies ranged from 55.2% to 56.7%, and in pupae, it ranged from 46.1% to 48.7% across different feeding substrates. Notably, pupae fed with Ulva sp., exhibited the highest protein content at 48.7%. Lipid content in adult flies ranged from 10.0% to 13.0%, while in pupae, it ranged from 8.8% to 11.4%. Codfish frames had the highest lipid content in both pupae (11.4%) and adults (13%). The most abundant fatty acid in Fucus sp. – fed pupae and adult flies was oleic acid (18:1 n-9), while palmitoleic acid (16:1 n-7) dominated in other treatments. It is worth highlighting that docosahexaenoic acid (22:6 n-3) was reported for the first time in a seaweed fly, namely when supplied with fish processing waste. These findings suggest that Fucellia maritima may be a promising complementary ingredient for formulating marine aquafeeds.

Empirical evidence of alternative stable states in an estuary

Due to human activity, ecosystems are exceeding their ecological thresholds and shifting into undesired alternative stable states with new ecological configurations. Despite their purported ubiquity, it is uncertain whether estuaries can exist in multiple stable states. We use data from a 3.5-year study of invertebrate communities in an Australian estuary that is usually closed to the ocean to test for their existence. Sampling spanned a 1.5-year period of hypersalinity (>40 ppt) during a prolonged estuary closure, where salinity reached 122 ppt, and for two years during and after the estuary opened to the ocean when salinities were mesohaline (5–19 ppt). Two distinct community states occurred before and after the sandbar breached, with an intermediary period of invertebrate community impoverishment due to sediment scouring. During the closure, the community was simple (average of one taxa 100 cm−2) and dominated by larvae of terrestrial insects, most notably the halotolerant, non-biting midge Tanytarsus barbitarsis. After opening, the richness and abundance of invertebrates increased (average of four taxa and 84 individuals 100 cm−2) as polychaetes, molluscs and crustaceans colonised the estuary, although recovery was incomplete according to previous species records. Duration of estuary closure and salinity were the strongest drivers of composition. This study, together with evidence from the literature, suggests a salinity threshold of 60–65 ppt between states. These empirical data meet key criteria of alternative states, i.e. a clear transition between two distinct self-sustaining communities, indicating a regime shift triggered by an exogenous event. Our findings suggest that temporarily open and closed estuaries can exist in alternative stable states, with prolonged closures, hypersalinity, and sandbar breaching being key determinants of the switch between states. This situation may apply to other low-inflow estuarine systems, particularly in arid, semi-arid, or seasonally arid climates, and may become more frequent with human-induced climate change.

Exploring Aquaporin Diversity in Elateroidea: Insights From RNA-Seq Data Sets.

Osmoregulation, the physiological regulation of water and ion balance, is vital for the survival of both aquatic and terrestrial insects. In freshwater aquatic insects, such as those within the Lampyridae family, this function is important due to the natural variation of aquatic habitats. Aquaporins play a key role in this process by facilitating the rapid transport of water molecules across cell membranes, maintaining cellular water balance, and adapting to changes in external salinity. In this study, I investigate the genetic diversity and expression levels of aquaporins in Elateroidea, particularly focusing on the Lampyridae family, using transcriptomic data and in silico analyses. The results reveal the diversity of aquaporins and compare gene expression patterns between freshwater aquatic Lampyridae and terrestrial Elateroidea species, such as Lycidae, Phengodidae, and Elateridae. Phylogenetic analyses identify seven distinct clades of aquaporins and uncovered gene duplication events related to the diversification of Elateridae and Lampyridae. A comparative abundance analysis indicated higher aquaporin expression in aquatic fireflies, aligning with the need for efficient osmoregulation in aquatic environments. Additionally, stage-specific expression patterns in Aspisoma lineatum (Neotropical firefly) and Aquatica lateralis (Paleartic firefly) suggest species-specific strategies for coping with osmotic challenges during development. This study provides insights into the evolutionary adaptations of aquaporins in Elateroidea, highlighting their importance in both aquatic and terrestrial insect physiology.

Using Environmental DNA to Detect and Identify Sweetpotato Whitefly Bemisia argentifolii and Twospotted Spider Mite Tetranychus urticae in Greenhouse‐Grown Tomato Plants

ABSTRACTEnvironmental DNA (eDNA) consists of genetic material shed by living organisms, including those that are deceased, offering a unique opportunity to detect and identify terrestrial insect pests without requiring visual identification. The sweetpotato whitefly, Bemisia argentifolii, and the twospotted spider mite, Tetranychus urticae, are notorious for causing crop losses through virus transmission and direct feeding. Our study aimed to: (1) assess the effectiveness of B. argentifolii literature‐based PCR primers compared to newly developed primers for eDNA amplification, (2) evaluate the sensitivity of conventional PCR (cPCR) and real‐time quantitative PCR (qPCR) for detecting eDNA of B. argentifolii and T. urticae, (3) establish a rapid eDNA processing methodology using the LGC Biosearch Technologies QuickExtract DNA extraction kit and the Qiagen DNeasy Blood and Tissue kit, and (4) test the specificity of the developed primers against non‐target species. B. argentifolii and T. urticae were confined to tomato leaves (Solanum lycopersicum) using clip cages for 24 h, after which eDNA was collected from leaf surfaces using a water spray method, filtered, and processed for DNA amplification. While literature‐based primers showed sufficient sensitivity, their specificity for eDNA applications was inadequate, prompting the design of novel PCR primers for both pest species. Positive eDNA detection was achieved with both amplification methods, with qPCR proving more reliable than cPCR due to the latter's inconsistent performance with positive control samples. We also introduced a rapid eDNA processing approach using the QuickExtract DNA extraction kit, contrasting it with the more conventional Qiagen DNeasy Blood and Tissue kit. We believe that our findings are the first step toward the practical use of eDNA as a highly sensitive, early detection technique.

The bioconversion of dietary α-linolenic acid to eicosapentaenoic acid in Bombyx mori

n-3 Long-chain polyunsaturated fatty acids (n-3 LC-PUFAs), including eicosapentaenoic acid (EPA), are essential multifunctional nutrients in animals. Microorganisms such as microalgae are known to be n-3 LC-PUFA producers in aquatic environments. Various aquatic invertebrates, including Harpacticoida copepods, and a few terrestrial invertebrates, such as the nematode Caenorhabditis elegans, possess n-3 LC-PUFA biosynthetic enzymes. However, the capacity for n-3 LC-PUFA biosynthesis and the underlying molecular mechanisms in terrestrial insects are largely unclear. In this study, we investigated the fatty acid biosynthetic pathway in the silkworm Bombyx mori and found that EPA was present in silkworms throughout their development. Stable isotope tracing revealed that dietary α-linolenic acid (ALA) was metabolized to EPA in silkworm larvae. These results indicated that silkworms synthesize EPA from ALA. Given that EPA is enriched in the central nervous system, we propose that EPA confers optimal neuronal functions, similar to docosahexaenoic acid, in the mammalian nervous system.

Characterization of double-stranded RNA and its silencing efficiency for insects using hybrid deep-learning framework.

RNA interference (RNAi) technology is widely used in the biological prevention and control of terrestrial insects. One of the main factors with the application of RNAi in insects is the difference in RNAi efficiency, which may vary not only in different insects, but also in different genes of the same insect, and even in different double-stranded RNAs (dsRNAs) of the same gene. This work focuses on the last question and establishes a bioinformatics software that can help researchers screen for the most efficient dsRNA targeting target genes. Among insects, the red flour beetle (Tribolium castaneum) is known to be one of the most sensitive to RNAi. From iBeetle-Base, we extracted 12027 efficient dsRNA sequences with a lethality rate of ≥20% or with experimentation-induced phenotypic changes and processed these data to correspond to specific silence efficiency. Based on the first complied novel benchmark dataset, we specifically designed a deep neural network to identify and characterize efficient dsRNA for RNAi in insects. The dna2vec word embedding model was trained to extract distributed feature representations, and three powerful modules, namely convolutional neural network, bidirectional long short-term memory network, and self-attention mechanism, were integrated to form our predictor model to characterize the extracted dsRNAs and their silencing efficiencies for T. castaneum. Our model dsRNAPredictor showed reliable performance in multiple independent tests based on different species, including both T. castaneum and Aedes aegypti. This indicates that dsRNAPredictor can facilitate prescreening for designing high-efficiency dsRNA targeting target genes of insects in advance.

Exposure Pathways and Toxicity of Microplastics in Terrestrial Insects.

The detrimental effects of plastics on aquatic organisms, including those of macroplastics, microplastics, and nanoplastics, have been well established. However, knowledge on the interaction between plastics and terrestrial insects is limited. To develop effective strategies for mitigating the impact of plastic pollution on terrestrial ecosystems, it is necessary to understand the toxicity effects and influencing factors of plastic ingestion by insects. An overview of current knowledge regarding plastic ingestion by terrestrial insects is provided in this Review, and the factors influencing this interaction are identified. The pathways through which insects interact with plastics, which can lead to plastic accumulation and microplastic transfer to higher trophic levels, are also discussed using an overview and a conceptual model. The diverse impacts of plastic exposure on insects are discussed, and the challenges in existing studies, such as a limited focus on certain plastic types, are identified. Further research on standardized methods for sampling and analysis is crucial for reliable research, and long-term monitoring is essential to assess plastic trends and ecological impacts in terrestrial ecosystems. The mechanisms underlying these effects need to be uncovered, and their potential long-term consequences for insect populations and ecosystems require evaluation.

Influence of the dietary contribution of terrestrial insects to the condition factor of bleak Alburnus alburnus in a highly polluted lowland river.

Bleak Alburnus alburnus is a highly abundant but understudied fish species, and we know little about the trophic ecology of populations inhabiting rivers in central Europe. From an ecosystem perspective, this fish species is interesting as it is known to feed on surface insects, thereby linking the terrestrial with the aquatic habitat. In a previous study, we demonstrated that this flux is intensified, and dietary contribution of terrestrial insects is higher in fish inhabiting sections of the Spree River, Germany, that are polluted from iron oxides occurring from former lignite mining activities, and thus are characterized by lower abundances of aquatic insects. As terrestrial insects can be considered as food of lower quality (measured as long-chained polyunsaturated fatty acids, n-3 LC-PUFAs) compared to aquatic prey, it is reasonable to assume that the higher contribution of terrestrial insects is related to a lower body condition in fish. In this study, we explore the trophic ecology of riverine A. alburnus and their fitness consequences of feeding on terrestrial insects. We therefore modeled a terrestrial index from stable isotopes of hydrogen (δ2H) measured in the A. alburnus muscle tissue and compared individuals caught in locations upstream of a dam that were greatly influenced by iron oxides, with individuals caught in sections located downstream of a dam where passive remediation technologies are applied. The terrestrial index was significantly higher in A. alburnus caught in locations at high-iron concentrations, characterized by low abundances of aquatic prey, compared to A. alburnus caught in unpolluted habitats at low-iron concentrations. In contradiction to our hypothesis, the terrestrial index had no significant effect on the body condition of A. alburnus (measured as Fulton's condition factor K) in the sections downstream of the dam (i.e., at low-iron concentrations) and a significant positive, albeit weak, effect in sections upstream of the dam (i.e., at high-iron concentrations). However, the condition factor was generally lower in the high-iron section, potentially related to more direct effects of the iron oxide. We conclude that in A. alburnus, terrestrial insects can be considered as the less-favored food, unless the fish occur in environments where the aquatic food is of limited availability. Further research is needed to evaluate the direct and indirect effects, including the internal n-3 LC-PUFA synthesis as an adaption toward low-quality terrestrial prey on the fitness consequences of A. alburnus.

Functional traits of predators and decomposer prey determine context dependency in trophic control over ecosystems.

Research Highlight: Piccoli, G. C. d. O., Antiqueira, P. A. P., Srivastava, D. S., & Romero, G. Q. (2024). Trophic cascades within and across ecosystems: The role of anti-predatory defences, predator type and detritus quality. Journal of Animal Ecology, 00, 1-14. https://doi.org/10.1111/1365-2656.14063. Ecosystem functioning is controlled by the interplay between bottom-up supply of limiting nutrients and top-down animal feedback effects. However, the degree of animal versus nutrient control is context-dependent. A key challenge lies in characterizing this context dependency which is hypothesized to depend on differences in animal functional traits. Reporting on an important experiment, Piccoli etal. (2014) evaluate how interactions among functionally different predators and decomposer prey create context dependency in top-down control of a model system-tropical bromeliad tank ecosystems. Bromeliad plants hold water in their tanks supporting microcosm ecosystems containing terrestrial and aquatic insect larvae and arachnids. The ecosystems are supported by nutrients in plant litter that rains down from forest canopies into the tanks. Nutrients are released after litter is decomposed by a functionally diverse community of larval insect decomposers that differ in feeding mode and antipredator defence strategy. This decomposer community is preyed upon by an exclusively narrowly ranging aquatic insect larval predator and widely ranging spider predator that crosses between the aquatic and surrounding terrestrial ecosystems. Experimental manipulation of the animal community to test for the degree of control by predators mediated by the functionally diverse prey community included four treatments: (i) a control with the detritivores composing different function groups but without predators, (ii) the cross-ecosystem spider predator added, (iii) the purely aquatic damselfly larvae predator added and (iv) both predator types added to capture their interacting effect on ecosystem function (decomposition, nutrient release, and plant growth). Notably, the study resolved the causal pathways and strengths of direct and indirect control using structural equation modelling. These findings reveal how context dependency arises due to different capacities of the predators alone and together to overcome prey defences and control their abundances, with attendant cascading effects that diminished as well as enhanced decomposition and nutrient release to support bromeliad plant production. The study reveals that predators have a decided, albeit qualitatively and quantitatively different, hand in shaping the degree of bottom-up control through feedback effect on the release of limiting nutrients. This ground-breaking study provides a way forward in understanding the mechanisms determining context dependency in the control over ecosystem functioning.

Temperature influences desiccation resistance of bumble bees

Ongoing climate change has increased temperatures and the frequency of droughts in many parts of the world, potentially intensifying the desiccation risk for insects. Because resisting desiccation becomes more difficult at higher temperatures and lower humidity, avoiding water loss is a key challenge facing terrestrial insects. However, few studies have examined the interactive effects of temperature and environmental humidity on desiccation resistance in insects. Such studies on bees (Hymenoptera: Apoidea: Anthophila) are especially rare, despite their ecological and economic importance. Here, we crossed temperature (20, 25, and 30 °C) with humidity (<5, 50, >95 % RH) manipulations and measured time to mortality, water loss rates, and the water content at mortality of bumble bees (Bombus impatiens). We found that both higher temperature and lower humidity increased water loss rates, while warmer temperatures reduced survival time and lower humidity decreased water content at mortality. Additionally, we observed large intraspecific variation in water balance traits between colonies, and larger individuals survived longer and could tolerate more water loss before mortality. This study raises important questions about the mechanisms underpinning water loss in bumble bees and suggests that frequent access to nectar may be especially important for bumble bees’ water balance and survival in a warming and drying climate.

First evidence of feeding on micromammals and fish by a cyprinid species (Squalius carolitertii) in lacustrine food webs

The consumption of resources at multiple trophic levels reflects the omnivorous behaviour of various species. Despite the importance of omnivory in food web structure and stability, there are still few observational data to assess the omnivorous role of species in food webs. We first assessed the feeding of two cyprinid [northern Iberian chub (Squalius carolitertii) and northern straight-mouth nase (Pseudochondrostoma duriense)] and one salmonid (brown trout Salmo trutta) species in a mountain lake of the Iberian Peninsula, and then we studied the omnivorous behaviour and niche partitioning of the cyprinid species. A noteworthy result was the consumption of micromammals by northern Iberian chub. This species showed a high trophic flexibility feeding on diverse food types (detritus, vegetal rests, zooplankton, aquatic insects, terrestrial insects, micromammals and small fish), whereas northern straight-mouth nase fed mostly on detritus. We observed that the consumption of zooplankton decreased with increasing fish length in northern Iberian chub, whereas no evidence for ontogenetic dietary shifts were observed for northern straight-mouth nase. Brown trout fed only on cyprinids, acting as top predator in the studied mountain lake. Despite high dietary overlap between omnivorous cyprinids, our analyses suggested that omnivorous behaviour and ontogenetic dietary shifts of northern Iberian chub can be an important adaptive feature that may reduce food competition and enable species coexistence in mountain lakes. Our study shows that endemic omnivorous cyprinids can exploit alternative energy pathways and underlines the importance of omnivorous species as promoters of stability in lacustrine food webs. We highlight that the importance of occasional pulses of allochthonous energy sources fueling lacustrine food webs, such as micromammals and terrestrial insects, represent a particularly promising area for future research.

Lake food web structure in Teici Nature reserve, Latvia: fish presence shapes functioning of pristine bog lake food webs

Studies on the effects of fish presence on lake ecosystems are widespread but only a few have been conducted in pristine aquatic environments. We employed Ecopath model for assessing food web structure in two fish-inhabited and one fishless lake in a pristine bog area. We hypothesized that: (a) fish absence will raise trophic positions of macroinvertebrate predators; (b) fish predation will lead to higher overall predation rates on zooplankton; (c) fish predation on large bodied zooplankton will result in top-down cascading effect, increasing phytoplankton biomasses. We found that fish have direct and indirect effects on zoobenthic communities. Chironomid biomass was greater and predatory macroinvertebrate groups had a higher trophic level in the fishless lake than in fish-inhabited lakes. Consumption rates of the benthic consumer fraction were greater than that of the planktonic fraction in the fishless lake; the opposite was found in the two lakes with fish. No effects of fish presence on zooplankton were found and we explain this partly by the low water transparency masking the impact of fish. Terrestrial insects constituted a crucial part of adult fish diet and we conclude that terrestrial secondary production contributes to the trophic support of fish communities in pristine bog lakes.

A perspective on the impacts of microplastics on mosquito biology and their vectorial capacity.

Microplastics (plastic particles <5 mm) permeate aquatic and terrestrial ecosystems and constitute a hazard to animal life. Although much research has been conducted on the effects of microplastics on marine and benthic organisms, less consideration has been given to insects, especially those adapted to urban environments. Here, we provide a perspective on the potential consequences of exposure to microplastics within typical larval habitat on mosquito biology. Mosquitoes represent an ideal organism in which to explore the biological effects of microplastics on terrestrial insects, not least because of their importance as an infectious disease vector. Drawing on evidence from other organisms and knowledge of the mosquito life cycle, we summarise some of the more plausible impacts of microplastics including physiological, ecotoxicological and immunological responses. We conclude that although there remains little experimental evidence demonstrating any adverse effect on mosquito biology or pathogen transmission, significant knowledge gaps remain, and there is now a need to quantify the effects that microplastic pollution could have on such an important disease vector.

MEMS highly sensitive and large-area force plate for total ground reaction force measurement of running ant

Terrestrial insects exhibit agile manoeuvrability while running. However, the ground reaction force (GRF) in small insects remains poorly understood owing to its size and acting force. Here, we present a force plate for the measurement of total GRF during the running motion of ants with a force on the order of several tens of μN. The proposed force plate consists of a sufficiently large plate for several step cycles and four supporting cantilevers with highly sensitive piezoresistive elements. The plate and sensor chips were fabricated separately and combined during postprocessing. Two sizes of force plates were designed and fabricated for a large ant (Camponotus japonicas) and small ant (Messor aciculatus) with force resolution less than 1 μN. The developed force plates were calibrated by applying vertical forces at 32 points on the plate. Using the fabricated force plate, we measured the total GRF over several step cycles as the ant ran along the plate. Consequently, it was suggested that the ant ran with small vibrations in the direction of gravity.

Effects of mining activities on fish communities and food web dynamics in a lowland river.

Fish communities of streams and rivers might be substantially subsidized by terrestrial insects that fall into the water. Although such animal-mediated fluxes are increasingly recognized, little is known about how anthropogenic perturbations may influence the strength of such exchanges. Intense land use, such as lignite mining, may impact a river ecosystem due to the flocculation of iron (III) oxides, thus altering food web dynamics. We compared sections of the Spree River in North-East Germany that were greatly influenced by iron oxides with sections located downstream of a dam where passive remediation technologies are applied. Compared to locations downstream of the dam, the abundance of benthic macroinvertebrates at locations of high iron concentrations upstream of the dam was significantly reduced. Similarly, catch per unit effort of all fish was significantly higher in locations downstream of the dam compared to locations upstream of the dam, and the condition of juvenile and adult piscivorous pike Esox lucius was significantly lower in sections of high iron concentrations. Using an estimate of short-term (i.e., metabarcoding of the gut content) as well as longer-term (i.e., hydrogen stable isotopes) resource use, we could demonstrate that the three most abundant fish species, perch Perca fluviatilis, roach Rutilus rutilus, and bleak Alburnus alburnus, received higher contributions of terrestrial insects to their diet at locations of high iron concentration. In summary, lotic food webs upstream and downstream of the dam greatly differed in the overall structure with respect to the energy available for the highest tropic levels and the contribution of terrestrial insects to the diet of omnivorous fish. Therefore, human-induced environmental perturbations, such as river damming and mining activities, represent strong pressures that can alter the flow of energy between aquatic and terrestrial systems, indicating a broad impact on the landscape level.

Fatty Acid Profile and Escherichia coli and Salmonella sp. Load of Wild-Caught Seaweed Fly Fucellia maritima (Haliday, 1838) (Diptera: Anthomyiidae).

World aquaculture is expected to continue to grow over the next few decades, which amplifies the need for a higher production of sustainable feed ingredients for aquatic animals. Insects are considered good candidates for aquafeed ingredients because of their ability to convert food waste into highly nutritional biomass. However, commercially available terrestrial insect species lack n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), which are essential biomolecules for marine cultured species. Nevertheless, several coastal insect species feature LC-PUFAs in their natural fatty acid (FA) profile. Here, we analysed the lipidic profile of wild-caught seaweed fly Fucellia maritima, with a focus on their FA profile, to evaluate its potential to be used as an aquafeed ingredient, as well as to screen for the presence of pathogenic bacteria. Results showed that the flies had a total lipid content of 13.2% of their total dry weight. The main classes of phospholipids (PLs) recorded were phosphatidylethanolamines (PEs) (60.8%), followed by phosphatidylcholine (PC) (17.1%). The most abundant FA was palmitoleic acid (C16:0) with 34.9% ± 4.3 of total FAs, followed by oleic acid (C18:1) with 30.4% ± 2.3. The FA composition of the flies included essential fatty acids (EFAs) for both freshwater fish, namely linoleic acid (C18:2 n-6) with 3.4% ± 1.3 and alpha-linoleic acid (C18:3 n-3) with 3.4% ± 1.9, and marine fish, namely arachidonic acid (C20:4 n-6) with 1.1% ± 0.3 and eicosapentaenoic acid (C20:5 n-3) with 6.1% ± 1.2. The microbiological analysis found 9.1 colony-forming units per gram (CFU/g) of Enterobacteriaceae and no presence of Salmonella sp. was detected in a sample of 25 g of fresh weight. These findings indicate that Fucellia maritima biomass holds the potential to be used as an additional aquafeed ingredient due to its FA profile and the low count of pathogenic bacteria, which can contribute to the optimal growth of fish and shrimp with a low risk of pathogen transfer during the feed production chain.