Search Results (52)

Despite flies regularly visiting flowers, limited research has gone into their pollination ability on commercial crops. A national project in Australia aimed to identify fly species as potential managed pollinators for the horticultural industry and, in particular, avocado. This study investigated the ability of two calliphorids (Calliphora dubia and Calliphora vicina) and a syrphid (Eristalis tenax) fly species to pollinate Hass avocados in southwestern Australia. Four (4) field trials over three (3) years showed that each fly species (all found across Australia) was capable of pollinating Hass avocados when released into netted enclosures around multiple trees (12–26) during flowering. Trees enclosed with Eristalis tenax produced the highest fruit yield (18.0 kg/tree) outperforming trees pollinated by either C. dubia (11.6), managed honey bees in the open orchard (10.5) or C. vicina (6.8). Increasing fly numbers from 10,000 to 15,000 in the enclosures provided no additional pollination benefit. These results suggest that either E. tenax or C. dubia could be valuable managed pollinators for the avocado industry either with or without honey bees. Calliphora dubia was a significant pollinator during warmer flowering seasons and C. vicina was a useful pollinator during cold and wet flowering seasons. Full article

We conducted a mark–release–recapture study of the ringlet butterfly, Erebia pronoe glottis, in the Pyrenees to study population density, flight activity, dispersal, and nectar plant preferences. We found differences between both sexes in population density (males: 48/ha; females: 23/ha), sex ratio (2.1), and behaviour (75.4 vs. 20.5% flying). Both sexes used a wide range of nectar plants (Asteraceae, 40.6%; Apiaceae, 34.4%; Caprifoliaceae, 18.8%). However, local abundance appeared to be limited by the availability of nectar plants. Compared to a population of an extensively used pasture in the Alps, a significant increase in flight activity, but not in range, was observed. Movement patterns showed the establishment of home ranges, which significantly limited the dispersal potential, being low for both sexes (mean fight distances-males: 101 m ± 73 SD; females: 68 m ± 80 SD). A sedentary taxon such as E. pronoe glottis does not seem to be able to avoid the pressure of resource shortage by dispersal. As a late-flying pollinator, Erebia pronoe competes seasonally for scarce resources. These are further reduced by grazing pressure and are exploited by honey bees as a superior competitor, resulting in low habitat quality and, consequently, in comparatively low abundance of E. pronoe glottis. Full article

The honey bee is a crucial pollinator in urban ecosystems but faces multiple challenges, including habitat degradation, pollution, and parasitism by species such as the phorid fly, Apocephalus borealis Brues (Diptera: Phoridae). This study investigated honey bee abundance and the percentage of A. borealis parasitism in an urban environment in San Francisco, California. We monitored six sites weekly for six months using two sampling methods. Individual bees were weighed and observed for parasitoid emergence under controlled laboratory conditions. Our results indicate fluctuations in honey bee parasitism by A. borealis from September 2024 to May 2025, with four distinct peaks occurring in mid-September, February, late March, and early May. The highest parasitism rates exceeded 50% in early May, coinciding with increased temperatures and drops in relative humidity. These results suggest a potential link between abiotic conditions and parasitoid activity, highlighting the importance of long-term monitoring to understand the seasonal dynamics of host–parasite interactions in urban environments. Full article

Spring ephemerals have different pollination strategies to avoid the rareness and/or low activity of insect pollinators caused by low temperature in early spring. However, limited research has been conducted on the effects of elaborate petals and the pseudonectaries on petals on pollinator attraction. We examined the role of the elaborate petals and the pseudonectaries in pollinator attractions of the spring ephemeral Eranthis stellata (Ranunculaceae) using a combination of observational and experimental approaches. The results indicated that the color contrast created by the yellow pseudonectaries that did not secrete nectar on the white petals, was more attractive to both bees and flies as nectar guides, but only bees with relatively longer tongues could access nectar at the base of the petal tubes. Also, the pseudonectaries were food deception for fly visitors. Food deception as a mechanism to increase the efficiency of pollination has not been reported for Ranunculaceae or other basal eudicots. Full article

Essential oils have been utilized in the health, learning/memory, and agricultural fields, but not much is known about the biological activity of their individual components. Terpinyl acetate is a p-menthane monoterpenoid commonly found in cardamom, pine, cajeput, pine needle, and other essential oils. Using a cell culture model system, we found that terpinyl acetate is a potent and specific inhibitor of mitochondrial ATP production, suggesting it might function as a plant toxin. Remarkably, however, terpinyl acetate was not cytotoxic because cells switched to glycolysis to maintain ATP levels. Based on these findings, we hypothesized that terpinyl acetate might be employed to benefit plant survival by modulating metabolism/behavior of plant pollinators such as the honey bee. This hypothesis was tested by investigating terpinyl acetate’s effect on honey bee foraging. Free-flying honey bee flower color choice was recorded when visiting a blue-white dimorphic artificial flower patch of 36 flowers. The nectar–reward difference between flower colors was varied in a manner in which both learning and reversal learning could be measured. Terpinyl acetate ingestion disrupted reversal learning but not initial learning: this change caused bees to remain faithful to a flower color longer than was energetically optimal. Full article

Plastic pollution has become a critical environmental issue, with vast amounts of plastic waste accumulating in aquatic and terrestrial ecosystems. Plastic pollution poses significant risks to biodiversity by introducing toxic chemicals and disrupting biological functions. The drone fly, Eristalis tenax, is perhaps the most globally widespread hoverfly. This success is aided by its development as a rat-tailed maggot in a wide array of aquatic environments where it feeds on decaying organic matter. As an adult, E. tenax is a vital pollinator, visiting a wide range of crops and wild plants, and has been shown to vector pollen over hundreds of kilometres during seasonal migrations. Exposure to microplastics during larval stages has the potential to alter the provision of these ecosystem services and to provide a route for the long-distance vectoring of microplastics. To investigate this, we rear E. tenax in water contaminated with different concentrations of microplastic particles. We show that these plastics are retained in the gut from larval through to pupal to adult developmental stages. This contamination resulted in reductions of 33% and 60% in pupal and adult weight when exposed to the highest concentrations of microplastic particles but resulted in no detectable effects on mortality or developmental length. Our results demonstrate the potential for the vectoring of microplastics by this highly mobile species. However, the associated reductions in body size likely have profound consequences for movement capability in terms of foraging and migration and should be further investigated for their impact on ecosystem service provision. Full article

The semi-deciduous Brazilian Atlantic Forest has faced intense fragmentation, impacting Metrodorea nigra St. Hill., a fly-pollinated and autochorous tree. We investigated population structure, inbreeding, and spatial genetic structure (SGS) across adult (Adu) and juvenile (Juv) generations in three fragmented populations of M. nigra in Ribeirão Preto, São Paulo, Brazil. We tested whether the magnitude of these effects could result from its mating system, seed dispersal, anthropogenic disturbances, matrix, and fragment size. Populations affected by selective logging, fire, and trail openings include M13-Rib (84 ha) and FAC-Crav (8 ha), both surrounded by sugar cane and BSQ-Rib (3 ha) in an urban matrix. We evaluated phenological events and germination rates in the BSQ-Rib fragment. We sampled leaves and amplified their DNA using ISSR (UBC 1, 2, 820, 834, 851, 858, 860, 886) and SSR (Mtn 1, 3, 13, 16, 19, 87, 95) molecular markers. Fst, PCoA, and AMOVA values suggest a lack of generational isolation, with most variance within generations. Inbreeding values were significant in all populations (Fis and Fit, p = 0.001), probably intensified by natural seed dispersal and pollinator behavior favoring geitonogamy. However, fragmentation, anthropogenic disturbances, and the surrounding matrix influenced SGS. The urban BSQ-Rib fragment recorded the highest SGS values (26 m Juv, 24 m Adu [ISSR]; 7 m Juv, 9 m Adu [SSR]), which may result in low fruit and seed production and germination rates. Despite being the largest fragment, M13-Rib shows SGS in the first distance class (19 m Juv, 24 m Adu [ISSR]; 0 m Juv, and 10 m Adu [SSR]), possibly due to selective logging and fire. FAC-Crav, a more conserved fragment, showed no SGS in adults but punctual SGS in juveniles (27 m [ISSR] and 8 m [SSR]), pointing to it as a promising source for seed collections for reforestation purposes. In summary, inbreeding in M. nigra, influenced by pollinator behavior and seed dispersal, along with fragmentation, anthropogenic disturbances, and the surrounding matrix, are critical in shaping SGS. These factors potentially impact the reproductive success of M. nigra and their long-term survival in the face of climate change. Full article

Orchids have evolved flowers with unique morphologies through coevolution with pollinators, such as insects. Among the floral organs, the lip (labellum), one of the three petals, exhibits a distinctive shape and plays a crucial role in attracting pollinators and facilitating pollination in many orchids. The lip of the terrestrial orchid Habenaria radiata is shaped like a flying white bird and is believed to attract and provide a platform for nectar-feeding pollinators, such as hawk moths. To elucidate the mechanism of lip morphogenesis, we conducted time-lapse imaging of blooming flowers to observe the extension process of the lip and analyzed the cellular morphology during the generation of serrations. We found that the wing part of the lip folds inward in the bud and fully expands in two hours after blooming. The serrations of the lip were initially formed through cell division and later deepened through polar cell elongation. Transcriptome analysis of floral buds revealed the expression of genes involved in floral organ development, cell division, and meiosis. Additionally, genes involved in serration formation are also expressed in floral buds. This study provides insights into the mechanism underlying the formation of the unique lip morphology in Habenaria radiata. Full article

Indonesia is known for its incredible diversity of insects. Being ectothermic, insects are influenced by environmental factors. The relationship between insect diversity and the environment can be understood using multivariate analysis. The Paseh District in Sumedang Regency has various land uses, including gardens, rice fields, and plantations. Changes in land use due to the construction of the Cisumdawu Toll Road can impact environmental factors, such as soil quality, microclimate, and water availability, which are critical for sustaining diverse insect communities. Similarly, changes in vegetation cover can alter temperature and humidity levels, impacting terrestrial insects adapted to specific climatic conditions. This study aims to gather information on the relationship between insect diversity and environmental factors in different land use types in the Paseh District. A preliminary survey was carried out to record land use types and determine sampling locations. An intensive survey was done to collect and identify flying insect samples, as well as to measure the environmental factors. The results were analyzed using the Shannon–Wiener Diversity Index (H’), Evenness Index (E’), Simpson’s Diversity Index (C), and Canonical Correspondence Analysis (CCA). The study found 115 species of flying insects, with mixed gardens having the highest diversity. The CCA results showed that temperature strongly and positively correlated with insect diversity across all land uses, while wind speed correlated positively with insect diversity in gardens. Altitude correlated negatively with insect diversity in mixed gardens but positively in rice fields. Humidity had a strong positive correlation with insect diversity in other land uses. This research is important for understanding how land use types and environmental factors influence flying insect diversity, which is crucial for conserving biodiversity and maintaining essential ecosystem services such as pollination and pest control. Its impact lies in providing scientific data to guide sustainable land management practices, support agricultural productivity, and inform policies for biodiversity conservation in the Paseh District and similar regions. Full article

Among flying insects, Diptera were the main visitors and colonisers of aquatic and terrestrial habitats in an Alpine glacial floodplain (NE Italy) at 2400 m a.s.l. In all, 4317 dipteran adults were collected using different collection techniques in, on, and out of the water: pond and drift nets, and emergence and Malaise traps, with a different periodicity: biweekly and every three hours for four consecutive days, in early and late summer 2015. Thirty-eight families in all, and 56 species within seven Brachycera families, were identified. Specifically, Chironomidae (36%) within Nematocera and Empidoidea families (23%), and Muscidae (9%) within Brachycera, prevailed. Chironomidae seemed to emerge and fly mainly in late morning–early afternoon, while most Brachycera were more active in late afternoon. Some ecological notes are given for seven Brachycera families, including Muscidae as the predominant family of anthophilous dipterans and the most efficient pollinators in mountain habitats and in the deglaciated areas of the proglacial forelands. Three genera of Muscidae were found as the main representatives of these environments: Thricops Rondani, Spilogona Schnabl, and Phaonia Robineau-Desvoidy). Among these genera, noteworthy was the finding of Spilogona triangulifera (Zetterstedt) as being new to the Italian fauna. Full article

Climate change effects, including temperature extremes and water stress, cause abiotic stress in plants. These changes directly affect flowering and the flower reward system for pollinators, influencing plant–pollinator interactions and ultimately seed production in flowering plants. Here, we tested the effects of water deprivation on the behavior of various pollinator species, plant–pollinator interactions, and the seed yield of sunflower, Helianthus annuus L. (Asteraceae). Sunflower was sown during four different months (January–April) and subjected to two different water availability levels (well-watered and water-deprived). Pollinator abundance was recorded five times a day (8:00 am, 10:00 am, 12:00 pm, 2:00 pm, and 4:00 pm) from flower heads and the florets. In addition, foraging behavior was also recorded. We found that lowest abundance, visit duration, and visitation rate occurred in April-sown sunflower. The European honey bee Apis mellifera L. (Hymenoptera: Apidae) was the most abundant visitor to sunflower, the hover fly Eristalinus aeneus (Diptera: Syrphidae) exhibited the longest visit duration, while Xylocopa sp. (Hymenoptera: Apidae) exhibited the highest visitation rate. The visitation rate of bees was significantly affected by water stress, with more bee visits occurring under well-watered conditions. Additionally, plant parameters, including flower head diameter, head weight, seed number, and seed weight, were significantly lower in the water-deprived treatments in April-sown sunflower. Open flowers without the pollination exclusion cages showed a higher yield, indicating the pollination dependence of sunflower. In conclusion, the plant modifications induced by sowing months and water-deprived conditions may alter pollinator behavior and may ultimately affect sunflower yield. Full article

Ceratitis capitata, known as the Mediterranean fruit fly (Medfly), is a major dipteran pest significantly impacting fruit and vegetable farming. Currently, its control heavily relies mainly on chemical insecticides, which pose health risks and have effects on pollinators. A more sustainable and species-specific alternative strategy may be based on double-stranded RNA (dsRNA) delivery through feeding to disrupt essential functions in pest insects, which is poorly reported in dipteran species. Previous reports in Orthoptera and Coleoptera species suggested that dsRNA degradation by specific nucleases in the intestinal lumen is among the major obstacles to feeding-mediated RNAi in insects. In our study, we experimented with three-day adult feeding using a combination of dsRNA molecules that target the expression of the ATPase vital gene and two intestinal dsRNA nucleases. These dsRNA molecules were recently tested separately in two Tephritidae species, showing limited effectiveness. In contrast, by simultaneously feeding dsRNA against the CcVha68-1, CcdsRNase1, and CcdsRNase2 genes, we observed 79% mortality over seven days, which was associated with a decrease in mRNA levels of the three targeted genes. As expected, we also observed a reduction in dsRNA degradation following RNAi against nucleases. This research illustrates the potential of utilizing molecules as pesticides to achieve mortality rates in Medfly adults by targeting crucial genes and intestinal nucleases. Furthermore, it underscores the importance of exploring RNAi-based approaches for pest management. Full article

Optical sensors have shown significant promise in offering additional data to track insect populations. This article presents a comparative study between abundance measurements obtained from a novel near-infrared optical sensor and physical traps. The optical instrument, named an Entomological Bistatic Optical Sensor System, or eBoss, is a non-destructive sensor operating in the near-infrared spectral range and designed to continuously monitor the population of flying insects. The research compares the mosquito aerial density (#/m³) obtained through the eBoss with trap counts from eight physical traps during an eight-month field study. The eBoss recorded over 302,000 insect sightings and assessed the aerial density of all airborne insects as well as male and female mosquitoes specifically with a resolution of one minute. This capability allows for monitoring population trends throughout the season as well as daily activity peaks. The results affirmed the correlation between the two methods. While optical instruments do not match traps in terms of taxonomic accuracy, the eBoss offered greater temporal resolution (one minute versus roughly three days) and statistical significance owing to its much larger sample size. These outcomes further indicate that entomological optical sensors can provide valuable complementary data to more common methods to monitor flying insect populations, such as mosquitoes or pollinators. Full article

The use of the blow fly Calliphora vicina as a potential pollination species to augment the current reliance on honeybees (Apis mellifera) in Australian horticulture requires knowledge of how best to mass-rear this fly species. Calliphora vicina lays eggs onto carrion soon after death, and the resultant larvae that hatch are necrophagous and feed on the decomposing tissues of the dead animal. Newly hatched larvae of this fly were provided with plant-based meals (soya bean and canola) and compared with larvae provided with livestock-derived meatmeal to determine if plant-based meal could be used to mass-rear this blow fly species. Both soya bean and canola meal media did not support larval survival through to adult emergence. The addition of only 10% whole egg powder to the plant-based meals enabled survival to eclosion of 39% and 13% on soya bean and canola-based media, respectively, compared with 76% on livestock-based meatmeal with 10% whole egg powder. Larvae fed a diet of livestock-based meatmeal with 10% whole dried egg powder had the fastest development to the pupal stage, the highest pupation rate, the heaviest pupae, and the highest subsequent adult eclosion. This study concluded that the use of plant-based meals as a diet for the mass-rearing of the blow fly C. vicina was not a viable option. Full article

Insects play an essential role as pollinators of wild flowers and crops. At the same time, pollinators in agricultural environments are commonly exposed to pesticides, compromising their survival and the provision of pollination services. Although pollinators include a wide range of species from several insect orders, information on pesticide sensitivity is mostly restricted to bees. In addition, the disparity of methodological procedures used for different insect groups hinders the comparison of toxicity data between bees and other pollinators. Dipterans are a highly diverse insect order that includes some important pollinators. Therefore, in this study, we assessed the sensitivity of two hoverflies (Sphaerophoria rueppellii, Eristalinus aeneus) and one tachinid fly (Exorista larvarum) to a neonicotinoid insecticide (Confidor^®, imidacloprid) following a comparative approach. We adapted the standardized methodology of acute contact exposure in honey bees to build dose–response curves and calculate median lethal doses (LD₅₀) for the three species. The methodology consisted in applying 1 µL of the test solution on the thorax of each insect. Sphaerophoria rueppelli was the most sensitive species (LD₅₀ = 10.23 ng/insect), and E. aeneus (LD₅₀ = 18,176 ng/insect) the least. We then compared our results with those available in the literature for other pollinator species using species sensitivity distribution (SSD). Based on the SSD curve, the 95th percentile of pollinator species would be protected by a safety factor of 100 times the Apis mellifera endpoint. Overall, dipterans were less sensitive to imidacloprid than most bee species. As opposed to most bee species, oviposition and fecundity of many dipteran species can be reliably assessed in the laboratory. We measured the number of eggs laid following exposure to different insecticide doses and assessed the potential trade-off between oviposition and survival through the sublethal sensitivity index (SSI). Exposure to imidacloprid had a significant effect on fecundity, and SSI values indicated that oviposition is a sensitive endpoint for the three dipteran species tested. Future studies should integrate this information related to population dynamics in simulation models for environmental risk assessment. Full article