Abundance Of Diptera Research Articles

Pan traps: An effective tool for monitoring phenological changes in insect floral visitors and their relationship with floral resources in a coastal Mediterranean forest

Precise monitoring of insect floral visitors and their relationship with floral resources throughout the flowering season provides baseline information to help us understand long-term changes in plant-pollinator interactions and improve pollinator conservation strategies. Pan traps are one of the methods most used for monitoring insect floral visitors and several studies have already linked the abundance and richness of these floral visitors with floral resources. However, less research has been conducted into the effectiveness of pan traps for monitoring phenological changes in the floral visitor community with regard to floral resources. We used pan traps to study the species composition and the abundance of insect floral visitors and their relationship with flower richness in a coastal forest throughout the entire flowering season for two consecutive years. Captures were confirmed to be floral visitors through field survey studies. Pan traps were effective for revealing changes in the abundance and species composition of floral visitor communities during and between years that correlated with changes in floral richness and species composition. Changes in floral visitor abundance showed a different bias in their association with floral richness. Thus, while Hymenoptera and Diptera abundance tended to be negatively correlated with floral richness, Coleoptera abundance tended to be positively correlated, although such correlations could change from year to year. There were two significantly different groups of flowering plant and floral visitor species: one in spring and the other in summer. Each period was characterized by unique overlap between some floral visitors and their floral resources, suggesting that to monitor floral visitors effectively both communities need to be considered. Interestingly, the floral phenology in this coastal forest extended longer than that of more inland communities, so reliable monitoring of floral visitors throughout the floral season may help us to better understand the role of coastal plant communities in the stabilization of the pollinator networks of more inland communities. Overall, phenology patterns need to be taken into account for pan trapping to become an effective methodology for monitoring floral visitor communities, considering both intra-year (spring and summer communities) and inter-year variations.

Seasonal population dynamics of Diptera families in deciduous forests of Central European Russia

Seasonal rhythms have been found in practically all groups of insects, but in Diptera they have been studied to a lesser extent. In deciduous forests of the European part of Russia (Republic of Mordovia, Temnikov district) seasonal dynamics of Diptera abundance was studied in 9 families (Tipulidae, Lonchaeidae, Aulacigastridae, Milichiidae, Heleomyzidae, Anthomyiidae, Muscidae, Fanniidae, Calliphoridae). Two peaks in seasonal abundance dynamics were characteristic of Tipulidae, Heleomyzidae, Fanniidae. Anthomyiidae had one peak in early June. Milichiidae had one peak in July. Muscidae had one peak in mid-August. Lonchaeidae and Aulacigastridae had a three-peak pattern with the highest abundance in June. Calliphoridae experienced a gradual increase in abun-dance from June and had a peak in early September. Numbers of Phaonia pallida (Muscidae) were at a minimum in June at different heights from the soil surface and gradually increased with peaks in August and September. The first individuals of Thricops simplex (Muscidae) did not appear in the traps until the first half of July. Thereafter its numbers increased very rapidly and reached a maximum in early September.

Influencia de las prácticas agrícolas en los ensambles de macroinvertebrados en la Patagonia (Argentina)

Aquatic species in agricultural areas are often exposed to concentrations of pesticides and fertilizers that can affect the entire community. This study aimed to monitor the presence of nutrients and pesticides (organophosphates and carbamates) and evaluate their effects on the composition of macroinvertebrate assemblages at two sites in the Neuquén River, both upstream (UNR) and downstream (DNR) of an area of intensive cultivation of pome fruit trees. Physicochemical parameters in water samples from UNR and DNR were not significantly different, except for nitrate (NO3-). Pesticides analyzed were below detection limits in water and sediment samples. Insects constituted 52.76% of the total individuals in UNR and, among them, Ephemeroptera was the most abundant taxon (n=419). On the other hand, 67.67% of the individuals in DNR were insects, and most of them belonged to the Order Diptera (n=1156). The abundance of Diptera and Ephemeroptera individuals was significantly different between sites. In addition, the temporal variation of richness within each site showed significant differences (P<0.05). There were 15 shared species and a Jaccard’s abundance-based index indicated 37.8% taxonomic similarity. In summary, there were no significant differences in abundance and diversity between UNR and DNR. However, there were differences in taxa richness and composition, with a low percentage of similarity between sites. The above can be observed in the canonical correspondence analysis, which shows a clear relationship between environmental variables and the distribution pattern of macroinvertebrate assemblages.

Effects of aerial adulticiding for mosquito management on nontarget insects: A Bayesian and community ecology approach

AbstractDiseases transmitted by mosquitoes are emerging across the globe in a broad range of urbanized, rural, and natural environments inhabited by their vector species. Because applications of insecticides remain the most effective, and often the only available tool to prevent or control mosquito‐borne disease outbreaks, their use and scope continue to expand. However, the effects of multiple insecticide applications targeting adult mosquitoes on nontarget insect communities remain poorly characterized. To remedy this knowledge gap, we conducted an evaluation of five aerial insecticide applications on insect communities in a natural environment near Salt Lake City, Utah. Employing a before–after–control–impact approach, we assessed abundance and community composition changes over the study period utilizing Bayesian and community ecology analytical methods. We observed no discernible effects on most insect taxa, and there were no changes in the overall insect community composition. The abundance of Diptera, Coleoptera, and Hemiptera declined in control and treatment sites, Odonata increased over the period of the study, and Hymenoptera and Lepidoptera remained similar, suggesting seasonal trends rather than treatment effects. The only consistently detectable treatment effect was on nonbiting midges (Diptera: Chironomidae), that are closely related to mosquitoes taxonomically and have similar body size and diel activity. Midge abundance declined by 79.9% (95% credible interval: 58.4–91.9). Overall posttreatment abundance decline of 62.2% (95% credible interval: 22.5–87.8) was also detected for leafhoppers (Hemiptera: Cicadellidae), but, these declines were inconsistent and may be attributed to natural variability rather than the treatment effect. Treatment frequency, location, life‐stage targeting, and application techniques may mitigate the effects of mosquito control on nontarget insects to allow protecting human health while limiting environmental impacts.

Diversity of Diptera at Agri-Biodiversity Park, Hyderabad

The diversity and abundance of Diptera at the Agri-biodiversity Park, Professor Jayashankar Telangana State Agricultural University, Hyderabad was studied from September 2019 to January 2020. Five collection methods (pitfall trap, yellow pan trap, manual collection, light trap and yellow sticky trap) were used and 6739 individuals under 27 families were collected. The results revealed that the most abundant family was Dolichopodidae (10.76%) followed by Sarcophagidae (10.19%) and Ceratopogonidae (8.92%). Yellow pan trap collected maximum number of individuals (2789), and revealed occurrence of maximum number of families (18). Shannon-Weiner diversity Index, Margalef’s species richness index and Pielou’s evenness index of the study area were 2.953, 2.949 and 0.896, respectively, indicating rich diversity of Diptera.

Arthropod biodiversity associated to European sheep production systems

The rural territories linked to European sheep systems still cover wide areas and provide multiple ecosystems services although the current situation of the associated biodiversity is not fully understood. In this study the foliage arthropods (including pollinators), the vegetation cover and height, the number of flowers and plant species richness were evaluated in 9 sheep grazed lands from 5 EU countries with different livestock management strategies and dominant vegetation. The total abundance of arthropods, the abundance of Diptera and Heteroptera, sward height and plant species richness were higher in more extensive than in more intensively managed farms. The total abundance and the abundance of most of the orders were highest in mountain areas (MP) and lowest in improved pastures (IMP) whereas the total arthropod richness showed no differences and the richness of pollinators was lower in IMP than in MP (p < 0.01) and semi-natural pastures (SN, p < 0.01). The grass cover was higher in IMP than in the rest of the areas whereas forb cover was higher in SN than in IMP (p < 0.01). The plant species richness peaked in MP whereas the number of flowers showed no significant differences. Sward height correlated positively with forb cover, plant species richness, the richness of the whole arthropod community, the abundance of several orders like Araneae, Diptera or Homoptera, as well as with the richness of the pollinator community. The community composition of the total arthropod fauna (p < 0.01) and the pollinators in particular (p < 0.05) differed between management strategies and more diverse groups were linked to the areas under more extensive management. Both communities (total and pollinators) also differed in composition between the types of vegetation (p < 0.01) and less diverse assemblages with low abundant taxa were associated to IMP and SN whereas more diverse groups were linked to MP and grassland-forest (WP) in both cases. A better understanding of the flora-fauna dynamics in sheep grazed pasturelands is essential for the proper conservation of the biodiversity and other ecosystem services, as well as for the maintenance of sustainable sheep systems relying on the natural resources.

Landscape and farm-level management for conservation of potential pollinators in Indonesian cocoa agroforests

Cocoa (Theobroma cacao L.), a major commodity globally, depends on insects for pollination. However, the cocoa pollinator identity is largely unknown and there are important knowledge gaps regarding landscape and farm-level management driving pollinators. Here we analyzed flower visitation with two approaches to quantify how landscape and farm-level factors affect potential pollinators (flower visitors) of cocoa in Central Sulawesi, Indonesia. In the first approach (landscape and farm-level) we selected 18 farms and focused on the relative importance of distance to forest (m), potential-pollinator habitats surrounding the farm (i.e. secondary forests and cocoa agroforests [%]), canopy cover (%), leaf-litter amount (kg/m2), and cocoa flower abundance for flower visitors. In the second approach (experimental farm management) we manipulated leaf-litter in 24 farms, because high leaf-litter is suggested to enhance flower visitors. We found that ants and Diptera were the most common flower visitors, and although previous studies suggest ceratopogonids as main cocoa pollinators, none were captured in this study. In the landscape and farm-level approach, potential-pollinator habitats surrounding the farm, and increased canopy cover enhanced ant and Diptera abundance, whereas distance to forest had no effect. In the experimental farm management approach, potential-pollinator habitats surrounding the farm rather than leaf-litter manipulation increased Diptera and ant abundance. In summary conservation of forests and agroforests surrounding the farm, maintaining canopy cover and minimum leaf-litter enhance cocoa flower visitors. Thus, farms with shade trees embedded in a biodiversity-friendly landscape are important for conservation of potential pollinators and pollination services and, thereby, promotion of sustainable cocoa.

Dam cascade alters taxonomic composition of benthic macroinvertebrate community in upper Yangtze River

AbstractCascade dams segment river connectivity, modify the hydrological process, and change the hydraulic properties, thus influencing the river ecosystem significantly. Ecological effects of dams have been extensively studied, but investigations on zoobenthos in a large area covering tributaries and mainstream with cascade dams are lacking. Here, we studied the features of benthic macroinvertebrate assemblages in the lower Jinshajiang River, which is the upper reach of the Yangtze River. Over 15,000 macroinvertebrate individuals were collected in the mainstream and eight tributaries. Altogether, 105 taxa belonging to 19 orders and 55 families were identified. The structure of benthic macroinvertebrate assemblages was considerably different between the natural‐flow reach and the reservoir reach in the mainstream. The diversity and abundance of Ephemeroptera, Trichoptera, and Megaloptera decreased to almost zero as a result of dam impoundment. By contrast, the abundance of Diptera, Chironomidae, and Tubificida increased significantly in the mainstream reservoir reach. The diversity of macroinvertebrate species in the mainstream reservoir reach was only half of that in the natural‐flow mainstream. The difference between macroinvertebrate assemblages in natural‐flow mainstream and tributaries was insignificant. Therefore, dam construction was considered the main cause of macroinvertebrate assemblage changes. Our results highlighted the necessity of maintaining sufficient natural river sections between cascade reservoirs to conserve the biodiversity of benthic macroinvertebrate.

Aquatic insect communities in headwater streams of Ciliwung River watershed, West Java, Indonesia

Abstract. Wakhid, Rauf A, Krisanti M, Sumertajaya IM, Maryana N. 2021. Aquatic insect communities in headwater streams of Ciliwung River watershed, West Java, Indonesia. Biodiversitas 22: 30-41. Ciliwung is one of the major rivers flowing from Cisarua (Bogor) to Jakarta. This study was conducted to assess and compare aquatic insect biodiversity and community structure in various headwater streams with respect to different land-use types. Ten stream reaches of the first and second orders representing three different land-use types in the surrounding area (forest, tea plantation, village) were selected. At each stream reach, the aquatic insects were collected using a D-net (0.4 mm mesh). Physico-chemical properties of water were directly measured in the field. Samples were collected every two months from April until December 2018. A total of 26531 aquatic insect specimens belonging to 75 species/morphospecies, 46 families, and 10 orders were recorded. The order Trichoptera was the most abundant comprising 51.28% of the total collected insects, followed by Diptera (30.5%), Ephemeroptera (7.52%), and Plecoptera (6.25%). The highest proportion of functional feeding group was filtering-collectors (61.34%), followed by shredders (16.29%), gathering-collectors (15.32%), and predators (6.94%). Abundance of Diptera and Plecoptera was significantly higher in forest streams, while Ephemeroptera in plantation streams, and Trichoptera in village streams. The peak population of Diptera, Ephemeroptera, and Trichoptera occurred in June (dry period), while Plecoptera in December (wet period). The forest streams exhibited the highest species richness and diversity. Analysis of similarity (ANOSIM) showed a low dissimilarity among streams of the three land uses (Global R=0.217; P&lt;0.001). The non-metric multidimensional scaling (NMDS) analysis showed that forest streams somewhat separated from plantation and village streams. The study provided important information on aquatic insect biodiversity, and indicated the need for forest area preservation in the headwater streams of Ciliwung River watershed.

Changes in phenology and abundance of suction‐trapped Diptera from a farmland site in the UK over four decades

1. Recently documented insect declines have caused major concerns and an increased interest in studies using long‐term population‐monitoring data.2. Samples from a 12.2‐m suction trap were used to examine trends in phenology and abundance of Diptera over four decades.3. The timing of peak flight has advanced by an average of 17 days, from 23 July in 1974 to 6 July in 2014.4. The abundance of flies has decreased by 37% over the studied period (from April to September), and peak abundance has decreased by 48%. The flight period has started earlier in recent years, and in 2014, the number of flies was higher in spring until the 31st of May than in 1974. Possible causes and impacts of these changes are discussed.

The occurrence and diversity of flies (Diptera) related to ruminant farming in southern Poland

The aim of the study was to determine the biodiversity of flies (Diptera) occurring in livestock buildings and in their direct proximity, in various systems of ruminants rearing. Flies were collected by net sweeping during the summer, in two cowsheds (one large-scale, and one traditional farm), and one specialist sheepfold, located in the Lesser Poland region of Poland. The insects were captured – both inside and outside the premises – three times (at 10:00, 12:00 and 14:00) on selected warm and sunny days of June, July and September, when animals were assumed to be the most harassed. A total of 18365 flies belonging to 13 families were obtained. The largest relative abundance of Diptera were from the Drosophilidae family (61.4%), and dominating Muscidae species – Musca domestica L., 1758 (19.2%) and Stomoxys calcitrans (L., 1758) (5.7%). More than half (55.5%) of all flies were captured in the morning, and their vast majority not inside a livestock building (28.2%), but in its close proximity (71.8%). This was particularly true of the large-scale cattle farm. The smallest number of insects, although with the highest biodiversity, were collected at the sheepfold. Regardless of their particular animal preferences, the insect species found were commonly occurring in different livestock sectors.

Saproxylic Diptera assemblages in a temperate deciduous forest: implications for community assembly.

Saproxylic insects, those associated directly or indirectly with decaying wood for all or part of their life cycle, compose a large proportion of forest organisms. Flies (Diptera) are often the most abundant and species-rich group of insects in forest microhabitats, yet most work to date on saproxylic insect diversity and ecology has focused on beetles (Coleoptera). We compared saproxylic Diptera assemblages reared from two tree species (sugar maple and American beech) at two stages of decay (early/young and advanced/old) for a total of 20 logs in an eastern Canadian Nearctic old-growth forest. We found that communities are distinct within both species type and decay stage of wood. Early decay stage wood is more variable in community composition than later decay stage; however, as the age of the decaying wood increases, the abundance of Diptera increases significantly. Most indicator species are discernible in later decay stage and wood type. We venture to suggest that stochastic and deterministic processes may play a role in driving Diptera communities in temperate deciduous forests. To retain the highest saproxylic Diptera diversity in a forest, a variety of decaying wood types at different stages of decomposition is necessary.

Use of field margins managed under an agri-environment scheme by foraging Barn Swallows Hirundo rustica

ABSTRACTCapsule: Barn Swallows Hirundo rustica were more likely to forage along arable field margins that were enhanced with wildflowers or legumes than control grass margins.Aims: To determine if foraging Barn Swallows displayed preferences for specific arable field boundary habitats (grass margins versus floristically enhanced margins) that were managed as part of an agri-environment scheme. We also aim to determine how Barn Swallow food abundance related to these habitats.Methods: Two foraging activity surveys took place on all grass and floristically enhanced margins (n = 56) present within the 600 m foraging range of seven Barn Swallow colonies during June and July 2016. Margin habitat use was measured by recording the presence/absence of foraging individuals during surveys, the total number of individuals and by calculating an index of foraging activity. Habitat information relating to adjacent boundary type, transect crop type and neighbouring crop type were also recorded.Results: Foraging Barn Swallows were significantly more likely to be recorded when survey transects included a floristically enhanced margin, but there was no significant impact of floristically enhanced margins on the total number of individuals recorded or on the index of foraging activity. Foraging activity was higher along grass verges and hedgerows when compared to treelines and was positively related to length weighted Diptera abundance (a measure of food biomass).Conclusion: Our results suggest that there may be a role for floristically enhanced margins in the conservation of Barn Swallows on arable farmland. More research, however, is needed to determine whether invertebrate-rich agri-environment scheme habitats can influence colony size or improve the breeding success of this species.

The Effect of Road Proximity on Arthropod Communities in Yukon, Canada + Supplementary Appendix 1 (See Article Tools)

Roads affect the ecosystems they traverse: road construction and maintenance constitute substantial disturbance, while roads and vehicles have hydrological, thermal, and other abiotic effects. Arthropod communities respond to these abiotic effects of roads, as well as to the indirect effects of vegetation changes. The Dempster Highway is a year-round gravel highway that travels 737 km through the Subarctic and Arctic ecosystems of Yukon and the Northwest Territories, Canada. In July 2016, in a Subarctic region of Yukon, we established nine transects spaced at 4 – 12 km intervals along a 56 km segment of the Dempster Highway and sampled arthropods at 1, 10, and 100 m from the highway on each transect. Our objective was to determine the effect of road proximity on the diversity, abundance, and composition of arthropod communities, with a special focus on the functionally and phylogenetically diverse group, Hymenoptera. We found that total arthropod abundance was lowest at the intermediate distance from the road, a pattern driven by high Diptera abundance close to the road and high Collembola abundance far from the road. We suggest that Diptera may be responding to increased moisture and plant biomass near the road, while Collembola may be responding to changes in soil characteristics. Hymenoptera abundance was greater close to the road than farther away, a pattern that may be driven by high Diptera parasitoid abundance near the road. Our results suggest that arthropods are good indicators of ecosystem function and that roads may have important effects on Subarctic ecosystem services (e.g., pollination, pest control). As infrastructural development continues in the Canadian North, it is of vital importance to anticipate and predict the effects of this development on the unique and diverse fauna of the Subarctic ecosystem.

Dryland management regimes alter forest habitats and understory arthropod communities

AbstractDryland forests, those characterised as having low precipitation and soil nutrients, account for over a quarter of forests globally. Increasing their productivity often relies on irrigation and fertilisation, but the impacts on the wider habitat are largely unknown. Understory invertebrates, in particular, play key roles in forest systems (e.g. nutrient cycling), but their responses to dryland forest management practices are untested. We investigated the impacts of irrigation, fertilisation and a combination of both on soil chemistry, understory vegetation, tree growth and understory arthropod communities in aEucalyptusplantation to establish linkages between dryland management and ecosystem responses. Fertilisation increased all soil nutrients (N, NO3N, P and K) with similar effects on the chemical composition of understory grasses. Fertilisation also caused declines in foliar silicon concentrations, an important herbivore defence in grasses. Irrigation increased growth of both understory plants (+90%) and trees (+68%). Irrigation increased the abundance of ground‐dwelling arthropods by over 480% relative to control plots, but depressed higher level taxon arthropod diversity by 15%, declining by a further 7% (−22%) in combined treatment plots. Irrigation also caused a surge in the abundance of Collembola (+1300%) and Isopoda (+323%). Fertilisation drove increases in the abundance of Isopoda (+196%) and Diptera (+63%), whereas fertilisation combined with irrigation increased populations of Thysanoptera (+166%) and Acarina (+328%). Airborne arthropods were less affected, but fertilisation increased the abundance of Apocrita (+95%) and depressed populations of Thysanoptera (−77%). Diptera abundance was positively related to understory vegetation growth, whereas the abundance of other groups (Collembola, Isopoda, Thysanoptera and Acarina) correlated positively with tree growth. We proposed that the large increases in populations of key detritivores, Collembola and Isopoda, were linked to increased leaf litter from enhanced tree growth in irrigated and combined treatment plots. Our findings suggest that dryland management can increase both plant productivity and abundance of arthropods, but cause arthropod diversity at the higher taxon level to decline overall.

Microhabitat heterogeneity promotes soil fertility and ground-dwelling arthropod diversity in Mediterranean wood-pastures

Mediterranean wood-pastures are extensive agroforestry systems that hold great ecological, social and cultural values, which consist of mixtures of grassland, scattered trees and shrubs, primarily used for livestock grazing. For centuries, low-intensity management in these landscapes has resulted in multiple microhabitats that favour biodiversity and are considered key elements for the long-term persistence of wood-pastures. However, the relative contribution of each microhabitat type to wood-pasture biodiversity and functioning remains poorly studied. We investigated the impact that different wood-pasture microhabitats have on soil chemical fertility and the decomposition food web. We analysed the two main microhabitats that make wood-pastures up – open grasslands and isolated trees – and three additional “litter-trapping” microhabitats – shrubs scattered in the grassland matrix, canopied shrubs and piles of pruning debris—in terms of soil chemical properties (organic matter content, total N, C:N ratio, available P, and exchangeable base cations), collembolan and dipteran (mostly detritivores) abundance, and carabid (seed-eaters and predators) and staphylinid (mostly predators) beetle abundance, body size, biomass, species richness and composition. Grasslands were the most different microhabitats, with the lowest soil nutrient content and particular carabid and staphylinid species composition. Trees had the highest soil fertility levels and abundance of Diptera and staphylinids, and held unique staphylinid assemblages. “Litter-trapping” microhabitats had medium to high soil nutrient values and shared a distinct staphylinid assemblage compared to grasslands and trees. Besides, scattered shrubs provided shelter for large-sized carabid and staphylinid predators, while canopied shrubs held the highest carabid abundance and biomass. “Litter-trapping” microhabitats retained tree leaves that would otherwise be lost to the wood-pasture, recovering nutrients to the system, and provided new habitat, shelter and food for detritivores and unique predator assemblages. “Litter-trapping” microhabitats thus enhanced soil fertility and the decomposition process, at the same time as increased the abundance and diversity of the communities of ground-dwelling detritivores and predators inhabiting wood-pastures. These findings confirmed that microhabitat heterogeneity resulting from low-intensity management is essential to maintain both the primary production and the biodiversity conservation value of wood-pastures.

Environmental drivers of biotic traits and phenology patterns of Diptera assemblages in karst springs: The role of canopy uncovered

Springs are stable environments with constant abiotic factors and therefore of use in variety of ecological experiments. We investigated the influence of canopy coverage on abundance, diversity, phenology and feeding guilds among Diptera assemblages at two rheocrene karst springs located near each other. The springs differed by canopy coverage while physicochemical characteristics of the water were similar. We set six emergence traps for one year at each spring covering all available microhabitats proportionally. We hypothesized that canopy coverage will have a strong effect on assemblage composition of Diptera as well as on diversity, abundance, phenology and feeding guilds composition between sites and that it will have a stronger effect than microhabitat characteristics. Similarity of species composition among springs was only 37.5%, with 23 common species/taxa out of 74 species/taxa. Abundance of Diptera was 8.5× higher at the open canopy spring, while diversity and number of species/taxa was higher at closed canopy spring. Emergence started earlier at open canopy site and was prolonged even in winter months. The majority of species were detritus feeders followed by collectors and there was no substantial difference among sites. We conclude that at springs with similar water characteristics, canopy coverage is the main driver of Diptera assemblage structure, with water velocity as a complementary factor. Substrate and other physicochemical factors seem less important.

Impact of invasive Rosa rugosa on the arthropod fauna of Danish yellow dunes

We compared the arthropod fauna of Rosa rugosa patches to the adjacent native yellow dune vegetation by pitfall trapping in the National Park Thy at the Danish North Sea coast. R. rugosa changes the vegetation from a dune grassland (dominated by Ammophila arenaria) poor in flowering plants to a low monospecific shrubbery rich in large flowers. We predicted faunal responses according to the changes in resource availability and environmental conditions promoted by this particular invasive plant: increased populations of flower-visiting insects and species of the phytophagous and detritivorous guilds, and a decrease in thermophilic predator species. A matched-pairs sampling design allowed us to isolate the effects of the vegetation change from those of potentially confounding landscape gradients. The arthropod communities were significantly affected by the vegetation change (redundancy analysis). Six taxa (Opiliones, Lepidoptera larvae, Hymenoptera, Diptera, Tipulidae, Geotrupidae) increased in abundance, and three (Araneae, Staphylinidae, Auchenorrhyncha) were reduced in the rose patches. The main exception from predictions was the lack of effects on large detritivores (isopods, diplopods). Overall, total catches were increased by 45 % in the rose patches, primarily caused by an increase in the abundance of Diptera. Arachnids and carabid beetles were analyzed at species level: the assemblage structure was significantly affected in arachnids but not in carabids. Arachnids showed reduced species richness and diversity and increased dominance in the rose patches, due to reductions among xerotherm species. The results indicate that considerable faunistic impoverishment of thermophilic dune specialist species can be expected in the future if R. rugosa is allowed to continue its invasion across the dune habitat.

Seasonal patterns in Tree Swallow prey (Diptera) abundance are affected by agricultural intensification

In many parts of the world, farmland bird species are declining at faster rates than other birds. For aerial insectivores, this decline has been related to a parallel reduction in the abundance of their invertebrate prey in agricultural landscapes. While the effects of agricultural intensification (AI) on arthropod communities at the landscape level have been substantially studied in recent years, seasonal variation in these impacts has not been investigated. To assess the contention that intensive cultures negatively impact food resources for aerial insectivorous birds, we analyzed the spatiotemporal distribution patterns of Diptera, the main food resource for breeding tree swallows Tachycineta bicolor), across a gradient of AI in southeastern Quebec, Canada. Linear mixed models computed from a data set of 5000 samples comprising >150,000 dipterans collected over three years (2006-2008) suggest that both Diptera abundance and biomass varied greatly during swallow breeding season, following a quadratic curve. Globally, AI had a negative effect on Diptera abundance (but not biomass), but year-by-year analyses showed that in one of three years (2008), dipterans were more abundant in agro-intensive landscapes. Analyses also revealed a significant interaction between the moment in the season and AI: In early June, Diptera abundances were similar regardless of the landscape, but differences increased as the season progressed, with highly intensive landscapes harboring fewer prey, possibly creating an "ecological trap" for aerial insectivores. While global trends in our results are in agreement with expectations (negative impact of Al on insect abundance), strong discrepancies in 2008 highlight the difficulty of predicting the abundance of insect communities. Our study indicates that predicting the effects of AI may prove more challenging than generally assumed, even when large data sets are collected, and that temporal variation within a season is important to take into consideration. While further work is required to assess the direct impacts of these seasonal trends in Diptera abundance on bird breeding success and post-fledging survival, management strategies in agricultural landscapes may need to consider the phenology of breeding birds and their dipteran prey in order to mitigate the potentially negative effects of AI late in the breeding season.

Entomofaunal Diversity of Diptera at FELDA Besout 6 Oil Palm Plantation

A study on diversity and abundance of Diptera was conducted for six consecutive months in oil palm plantation located in Felda Besout 6. Traps used in this study ware Malaise traps which been installed in three different study sites in the oil palm area. A total number of 2381 Dipterans were succesfully collected comprising seven families and 37 morphospecies during this study. Margin area recorded the highest number of Diptera collected with 905 individuals (seven families, 33 morphospecies) collected while the beneficial plants recorded the least abundant of Diptera with 615 individuals (seven families, 32 morphospecies). Cecidomyiidae was the most abundant family with 1551 individuals followed by the Culicidae, Chironomidae, Tephritidae, Tachinidae, Muscidae and Tipulidae with 480, 203, 55, 43, 43 and 6 respectively. Based on Shannon-Wiener Index (H’), all study sites (margin of an oil palm plantation, the beneficial plants and the interior of an oil palm plantation did not differ significantly with P> 0.05 with respectively recorded value (H’= 2.641), (H’= 2.569) and (H’= 2.504). The study showed that diversity and abundance of Diptera was higher in the margin of FELDA BESOUT 6 compared to the interior of the oil palm plantation and the beneficial plants.