Insect Species Richness Research Articles

The impact of forest characteristics, and bird and insect diversity on the occurrence of the Great Spotted Woodpecker Dendrocopos major and Grey-headed Woodpecker Picus canus in South Korea

ABSTRACT Capsule Although the Great Spotted Woodpecker Dendrocopos major and Grey-headed Woodpecker Picus canus have overlapping ranges in South Korea, they occur in areas with different forest structures and the occurrence of each species is associated with their main foods. Aims To investigate the biotic factors related to the occurrence of the Great Spotted Woodpecker and the Grey-headed Woodpecker, two species that frequently inhabit overlapping regions in South Korea. Methods Correlations between the occurrence of the two woodpecker species, forest characteristics, and bird and insect species richness were evaluated based on large-scale public data from the National Ecosystem Survey and a Forest Type Map. Results The occurrence of Great Spotted Woodpeckers was associated with forest stands with at least 75% coniferous trees, whereas the occurrence of Grey-headed Woodpeckers was negatively associated with forested areas with canopy cover exceeding 50%. The occurrence of both species was strongly and positively correlated with the species richness of forest birds. The occurrence of Great Spotted Woodpeckers was correlated with the species richness of Coleoptera, while that of the Grey-headed Woodpecker was correlated with the species richness of Hymenoptera and Diptera. Conclusion The co-occurrence of the two woodpecker species within shared habitats can be explained by low competition due to differences in preferred forest characteristics and in the food sources used by each species.

Large positive ecological changes of small urban greening actions

Abstract The detrimental effects of environmental change on human and non‐human diversity are acutely manifested in urban environments. While urban greenspaces are known to mitigate these effects and support functionally diverse ecological communities, evidence of the ecological outcomes of urban greening remains scarce. We use a longitudinal observational design to provide empirical evidence of positive ecological changes brought about by greening actions. We collected a plant–insect interactions data set 1 year before, and for 3 years after, a greenspace received a small greening action within a densely urbanised municipality. We then assessed how (i) insect species richness; (ii) the probabilities of occurrence, survival and colonisation of the insect community; and (iii) the plant–insect network structure varied across the 4 years of the study. As we understand, this is the first study to apply statistical and network analytical frameworks to quantitatively track how positive ecological changes accrue over time at a site after the implementation of a specific urban greening action. We show how a small greening action quickly led to large positive changes in the richness, demographic dynamics and network structure of a depauperate insect community. An increase in the diversity and complexity of the plant community led to, after only 3 years, a large increase in insect species richness, a greater probability of occurrence of insects within the greenspace and a higher number and diversity of interactions between insects and plant species. We demonstrate how large positive ecological changes may be derived from investing in small greening actions and how these contribute to bring indigenous species back to greenspaces where they have become rare or been extirpated by urbanisation. Our findings provide crucial evidence that supports best practice in greenspace design and contributes to re‐invigorate policies aimed at mitigating the negative impacts of urbanisation on people and other species.

Effects of nitrogen inputs and mowing on the abundance and species richness of herbivorous insects in a meadow steppe.

To reveal the effects of nitrogen (N) inputs and mowing on the abundance and richness of insect community in meadow steppe, we investigated the abundance and diversity of herbivorous insects under four treatments in Inner Mongolia meadow steppe in August 2022, including control, N addition, mowing, and combined N addition and mowing. At a long-term control experimental platform, we collected insects using the vacuum sampling method. The results showed that N addition significantly increased the abundance of herbivorous insects, and mowing significantly decreased the abundance of herbivorous insects. Nitrogen addition significantly increased insect abundance in unmown condition but not in the mown condition. The responses of insect abundance at the community level to N addition were mainly driven by the dominant groups, Cicadellidae and Lygaeidae, which was affected by the abundance of Gramineae species. In contrast, their responses to mowing were the opposite. Both N addition and mowing did not affect the diversity of herbivorous insects. Our results indicated that the responses of herbivorous insect abundance to N inputs and mowing were directly regulated by food resources. With increasing food resource availability, the abundance but not the diversity of herbivorous insects increased, with stronger responses of dominant groups than subordinate ones.

Description of the herbivore and natural enemy community associated with the seeds of an invasive plant in Brazil

Abstract Studies have shown that fruits of plants from the Fabaceae family harbour a diverse community of herbivorous insects and their natural enemies. Despite this observation, we still lack information on the specific interactions within these multi‐trophic communities. Herein, we describe the food web of insects associated with fruits and seeds of Leucaena leucocephala (Fabaceae), an invasive plant in Brazil, and their relationship with plant traits including seed biomass. We found 17 species of insects distributed across three trophic levels. The main herbivore species sampled was Acanthoscelides macrophthalmus (Coleoptera, Chrysomelidae, Bruchinae), which was responsible for most of the seed predation and associated with the highest parasitoid biodiversity (N = 10 species). Four other herbivorous species were lower in abundance, including a previously unreported Lepidopteran species with two parasitoids and one hyperparasitoid associated with it. Seeds with more mass promoted an increase in insect abundance, insect species richness, and the number of links and connectivity. We observed two native parasitoid species, Paracrias pluteus and Stenocorse suldamericanos, shift from herbivores on native plants to herbivores on the invasive L. leucocephala, consistent with a potential host shift. However, more investigation is required to ascertain the effects of recent shifts of native insect communities (on native plants) to non‐native ones and their consequences on plant fitness. Our study contributes to the understanding of the dynamics of communities and food webs in unknown systems, specifically in fruits of an invasive plant, and provides information about the influence of different plant traits on these communities.

Towards reliable estimates of abundance trends using automated non‐lethal moth traps

Abstract Monitoring insect abundance or species richness at high spatial and temporal resolution is difficult due to personnel, maintenance, and post‐processing costs as well as ethical considerations. Non‐invasive automated insect monitoring systems could provide a solution to address these constraints. However, every new insect monitoring design needs to be evaluated with respect to reliability and bias based on comparisons with conventional methods. In this study, we evaluate the effectiveness of an automated moth trap (AMT), built from off‐the‐shelf‐hardware, in capturing declines in moth abundance, by comparing it to a conventional, lethal trap. Both trap types were operated five times on 16 plots from the beginning of July 2021 to the end of August 2021. On average AMTs recorded fewer individuals than conventional traps. However, both trap types depicted the same seasonal decline of approximately 3% per day, which corresponded to a total difference of ~85% over the sampling period. Given our sample size, both trap types had the same limitations in their reliability to detect smaller changes in abundance trends. This first proof of concept demonstrated that AMTs depict large magnitude events such as phenological patterns just as well as conventional, lethal traps. Therefore, AMTs are a promising tool for future autonomous and non‐lethal monitoring, which paves the way for high temporal coverage and resolution in insect monitoring. However, this initial quantitative field test revealed that its long‐term applicability must be preceded by several adjustments to the image quality, power supply and to data transfer.

Changes in pollinators' flower visits and activities potentially drive a diurnal turnover of plant‐pollinator interactions

Abstract Plant‐pollinator interactions are essential to sustaining biodiversity and ecosystem functioning in terrestrial ecosystems and are variable on several spatiotemporal scales. On a fine temporal scale, the responses of pollinators to temperature and floral resource dynamics are likely to be related to the temporal turnover of plant‐pollinator interactions. However, the temporal dynamics of plant‐pollinator interactions on a fine scale are largely unknown. The present study aims to reveal the temporal turnover of plant‐pollinator interactions over a single day and investigates these interactions in semi‐natural grasslands in a Japanese agricultural landscape from the early morning to the evening. The interaction turnover was evaluated as temporal β‐diversity and divided into two components: interaction rewiring and species turnover. Insect species richness and the number of interactions showed hump‐shaped responses to the time of the day, and these responses differed for the different insect groups. Furthermore, the peak time of insect visitation frequency differed among 11 plant species. Interaction turnover (total β‐diversity) in the same day was higher than that in different days. Although interaction rewiring in different days was higher than that in the same day, species turnover had an opposite pattern. Over a single day, the relative importance of interaction rewiring was higher in the morning, while species turnover was higher in the evening. Around noon, interaction rewiring and species turnover were equally important. Therefore, the daily rhythm of pollinator activities and changes in the main floral resources drive the temporal turnover of plant‐pollinator interactions over a single day.

Insects benefit from agri-environmental schemes aiming at grassland extensification

One key target of agri-environmental schemes (AES) is maintaining biodiversity. However, if and how insect biomass and diversity benefit from grassland AES is not well known. Using Malaise trap samples from 72 grassland sites in four grassland dominated regions in Southern Germany, we investigated the effect of 1) local grassland AES (three levels: control, farm-wide, site-specific), and 2) an index of land use extensification (LEI, calculated for each site) on insect biomass and species richness of all insects, of five insect orders including all species (Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera), and two pollinator groups (Syrphidae, Apiformes). Moreover, the effect of grassland AES in the surrounding landscape was quantified. Insect samples were subjected to metabarcoding to create DNA barcode sequences which were then compared with reference libraries (BOLD; NCBI) and additionally classified using the Ribosomal Database Project (RDP) classifier. Resulting taxonomies were combined into a consensus taxonomy table and the potential minimum number of species per sample was estimated. Statistical analyses were carried out using Generalized linear mixed models and Bayesian inference. Our results indicated that species richness of many insect groups benefited from AES. As predicted by the regression model, presence of site-specific grassland AES increased the species richness of all insects (∼8%), Hymenoptera (∼27%), Lepidoptera (∼35%) and Syrphidae (∼26%). While Apiformes benefited most, we found an average increase of species richness in the presence of farm-wide AES by ∼82% and even more with site-specific AES ∼120%. We found that an increasing LEI, and thus more extensive management, positively affected insect diversity in grassland habitats. No effect of local AES and LEI on insect biomass was found. Moreover, the amount of grassland AES in the landscape was less important for insect diversity. We conclude that many grassland insects (especially pollinators) benefit from extensive management. However, we showed that the studied AES variants comprise variable management intensities hampering general AES recommendations for promoting insects. AES programs should, therefore, specifically reward extensification measures that were shown to benefit insect diversity. The integration of the land use extensification index (LEI) as a tool in the AES framework seems a promising approach to preserve and promote of insect diversity.

Assessing impacts of sulfur deposition on aquatic ecosystems: A decision support system for the Southern Appalachians

AbstractWith climate change and ongoing impacts from human development and resource extraction, US federal land management agencies are acutely concerned with managing for healthy aquatic ecosystems in the Southern Appalachian Mountain (SAM) Region. Here, we describe development of a spatial decision support application to assess the biological and ecological impacts of atmospheric S and N deposition on aquatic ecosystems of the region. We first summarize foundational published work to predict continuous maps of surface water acid neutralizing capacity (ANC) and soil base cation weathering (BCw). We use the predicted ANC and BCw maps to estimate steady‐state critical loads (CLs) of atmospheric S and N deposition. We included estimated CLs of atmospheric N to get a complete picture of CLs and potential exceedances. We then present a logic‐based decision support model for assessing effects of S and N deposition based on statistically modeled stream ANC and CL exceedance. The model is easily modified for continuous monitoring of CL exceedance patterns as new S and N deposition and ANC data become available. We present mapped model results for the SAM study area and an important subset of the region, the Great Smoky Mountains National Park. ANC modeling results revealed that predicted acid sensitivity was spatially variable, with areas of relatively low stream ANC (<50 μeq · L−1) and soil BCw (<50 meq · m−2 · year−1) predominantly found in certain critical areas. Within the Great Smoky Mountains National Park, evidence for S CL exceedance based on an ANC criterion of 50 μeq · L−1 was strong at locations where ambient S deposition was at least two times the CL. We also predicted likely impacts of CL exceedances on aquatic insect species richness and native fish abundance. Responses for insect species richness and fish impact showed variability similar to CL exceedance, with increasing impact positively correlated with elevation. Finally, we discuss ways that the decision support system can be used to prioritize management across the region.

Bird and insect pollinators differ in specialization and potential pollination services along disturbance and resource gradients

AbstractCombined studies of the communities and interaction networks of bird and insect pollinators are rare, especially along environmental gradients. Here, we determined how disturbance by fire and variation in sugar resources shape pollinator communities and interactions between plants and their pollinating insects and birds. We recorded insect and bird visits to 21 Protea species across 21 study sites and for 2 years in Fynbos ecosystems in the Western Cape, South Africa. We recorded morphological traits of all pollinator species (41 insect and nine bird species). For each site, we obtained estimates of the time since the last fire (range: 2–25 calendar years) and the Protea nectar sugar amount per hectare (range: 74–62 000 g/ha). We tested how post‐fire age and sugar amount influence the total interaction frequency, species richness and functional diversity of pollinator communities, as well as pollinator specialization (the effective number of plant partners) and potential pollination services (pollination service index) of insects and birds. We found little variation in the total interaction frequency, species richness and functional diversity of insect and bird pollinator communities, but insect species richness increased with post‐fire age. Pollinator specialization and potential pollination services of insects and birds varied differently along the environmental gradients. Bird pollinators visited fewer Protea species at sites with high sugar amount, while there was no such trend for insects. Potential pollination services of insect pollinators to Protea species decreased with increasing post‐fire age and resource amounts, whereas potential pollination services of birds remained constant along the environmental gradients. Despite little changes in pollinator communities, our analyses reveal that insect and bird pollinators differ in their specialization on Protea species and show distinct responses to disturbance and resource gradients. Our comparative study of bird and insect pollinators demonstrates that birds may be able to provide more stable pollination services than insects.

Little evidence for land-use filters on intraspecific trait variation in three arthropod groups

Abstract. Declines in species richness and abundance of insects over the last decades are often driven by anthropogenic land use and can have severe consequences for ecosystem functioning. Many studies investigated the effects of land-use intensification on the distribution of phenotypic traits across species at the community level, often with mixed results. However, biotic and abiotic environmental filters and potential selection act on individuals within each species, i.e., at the species' population level, and thus drive the extent of intraspecific phenotypic variation. Here, we compare the morphological trait variation within selected species of dung beetles, bees and grasshoppers and link this variation to land-use intensity in forests and grasslands. Selected traits included absolute body size measures and relative leg, wing or eye size, or shape and are often interpreted as “functional traits” in the context of specific ecological responses or effects. We predicted that trait variability among individuals of arthropod species is reduced in intensively used ecosystems (with pronounced environmental filtering) compared to low-intensity ones, particularly for arthropod species that were more abundant in intensively used sites (“land-use winners” compared to “losers”). In general, only few effects of land-use intensity on trait variation were found showing a decreasing variation with increasing land-use intensity in forests but an increasing variation in grasslands. Although many studies confirmed strong land-use impacts on species composition, diversity and trait distribution, including evidence from the same land-use gradients, we were not able to confirm consistent effects at the intraspecific level. However, the choice of which traits are included in analyses and the linkage between phenotypic variation and genetic variability can strongly influence the conclusions drawn on ecological processes. Therefore, we suggest extending the use of intraspecific trait variation on other, more specific response or effect traits and a broader range of species in future studies.

The Impact of Beehive Proximity, Human Activity and Agricultural Intensity on Diptera Diversity in a Mediterranean Mosaic of Agroecosystems, with a Focus on Pest Species.

Diptera, with their participation in pollination, significantly contribute to the maintenance of plant diversity, and they also have great potential for assessing habitat health and preserving it. A decline in their abundance and diversity has been recorded worldwide as a consequence of biotic, abiotic, and anthropic alterations. In addition to pollinators, these orders include agricultural and forestry pests, which are a threat to both cultivated and wild plants that are very important to the economy. Many pests have escaped from their native areas, and it is important to monitor their spread to implement sustainable means of control. Our study provides baseline information on Diptera and Vespidae diversity in the Mediterranean mosaic of agroecosystems, giving information on the importance of human influence on insect diversity. We carried out an insect inventory in Istria, Croatia, using a set of traps placed in the proximity of beehives. This study was also important in determining the presence of pests and newly introduced species. A total of 94 species from 24 families were recorded-7 important agricultural pests of Diptera and 17 new records for Croatia. The correlation between species diversity and environmental and anthropogenic factors leads to the conclusion that total insect species richness, pest species richness, and the first findings depend on human activities. The number of honeybee colonies negatively correlated with species richness, while anthropic influence positively affected total and pest species richness.

Diversity of insect flower visitors of cayenne pepper in agricultural landscapes, Banggai, Central Sulawesi

The existence of semi-natural habitats around agricultural land has the potential to support ecosystem services by providing resources for beneficial insects. The study aimed to analyze the abundance, diversity index, and evenness of the insects visiting cayenne flowers. This research was carried out in cayenne cultivation areas in the Banggai Regency. Sampling locations were divided into two categories: cayenne fields close to and far from forests or semi-natural habitats. Insect collection was carried out from June 2022 to August 2022, in the morning and evening, using insect nets. The results showed that 16 families and 52 cayenne flower-visiting insects were identified. Lasioglossum sp.3, Lasioglossum sp.5, Megachile sp.2, ?Parancistrocerus sp. and Rhynchium sp. have a higher abundance than the others. The highest Shannon and Wiener diversity index was found in cayenne fields in Tolisu Village (H'= 2.491), Mansahang (H'= 2.216), Salodik (H'= 2.145), and the lowest in cayenne fields in Kembang Merta Village (H'= 1.211), Dale-Dale (H'= 1.112 ), and Beringin Jaya (H'= 1.149 ). The highest evenness index (E) was found in the fields in Lembah Makmur Village (E= 0.9721) and Mansahang (E= 0.9172), and the lowest was found in cayenne fields in Petak Village (E= 0.3975) and Lenyek (E= 0.4405). The highest species richness was found in cayenne fields in Tolisu (14 species), Salodik (14 species), and Petak (12 species). Cayenne fields in the three villages are close to semi-natural habitats. Our findings show that agricultural land adjacent to semi-natural habitats has increased the species richness of cayenne flower visitor insects. Thus, semi-natural habitats are critical to sustaining insect communities in agricultural landscapes.

Arthropod fauna on the abaxial and adaxial surfaces of Acacia mangium (Fabaceae) leaves.

Acacia mangium (Willd., 1806) (Fabales: Fabaceae) is a fast growing, rustic, pioneer species, with potential to fix nitrogen, and for programs to recover degraded areas. The objective was to evaluate the distribution and the functional diversity of interactions and the K-dominance of arthropod groups on A. mangium saplings. The number of individuals of eleven species of phytophagous insects, three bee species, and fourteen natural enemy species were highest on the adaxial leaf surface of this plant. Abundance, diversity and species richness of phytophagous insects and natural enemies, and abundance and species richness of pollinators were highest on the adaxial A. mangium leaf surface. The distribution of five species of sap-sucking hemipterans and six of protocooperating ants (Hymenoptera), with positive interaction between these groups, and three bee species (Hymenoptera) were aggregated on leaves of A. mangium saplings. Aethalion reticulatum (L.) (Hemiptera: Aethalionidae) and Bemisia sp. (Hemiptera: Aleyrodidae); Brachymyrmex sp. and Camponotus sp. (Hymenoptera: Formicidae); and Trigona spinipes Fabricius (Hymenoptera: Apidae) were the most dominant phytophagous insects, natural enemies, and pollinators, respectively, on A. mangium leaves. Knowledge of preferred leaf surfaces could help integrated pest management programs.

Insect diversity on wheat as a new cultivation crop in West Sumatera

As a new crop is being introduced, wheat will affect the diversity of insects in the highlands, which is usually a vegetable planting area in West Sumatra. This study focuses on collecting, identifying, and comparing insect species richness and evenness on introduced wheat plants for one growing season. The result found 48 species from 45 families within seven orders of insects. The insect’s function was role of herbivores (12 families), predators (11 families), parasitoids (7 families), pollinators (6 families), and decomposers (9 families). The dominant insects found in wheat plantations are Aphididae as herbivores, Formicidae as predators, Onychiuridae as detritivores, Syrphidae as pollinators, and Ichneumonidae as parasitoids. Based on its function, the diversity index in herbivores is higher (H’=2.1) than in natural enemies (H’= 2) and detritivores (H’= 0.47). The highest evenness index was found for herbivores (E=0.85) from natural enemies (E=0.63) and detritivores (E=0.21). This paper will discuss wheat’s growth stages against species richness and evenness.

DIVERSITY, ABUNDANCE, AND SPECIES RICHNESS OF AERIAL INSECTS IN DRY LAND OF KEFAMENANU, NORTH CENTRAL TIMOR, EAST NUSA TENGGARA

Abstract: It is important to conduct this research to determine the diversity, species richness, and even distribution of aerial insects based on habitat characteristics in the dry land of Kefamenanu city, North Central Timor, East Nusa Tenggara. The research was conducted on three types of habitats, namely dry land, rivers, and lakes by purposive sampling method. Sampling was done by documenting specimens in each habitat, identified, inventoried, and analyzed quantitatively to obtain data on species diversity, species richness, and evenness of insect species. Results revealed that aerial insects in Kefamenanu City contained 9 orders, 25 families, 44 genera, 54 species, 1998 individuals in three habitat types with diversity index (H'=3,068), evenness index (E=0.774), richness index (R). = 6.974), and dominance index (0.074). Aerial insects in dry land habitat found in 8 orders, 18 families, 32 genera, 32 species, 514 individuals with diversity index (H'=2.735), evenness index (E=0.789), richness index (R=4.966), and dominance index. (0.092). Aerial insects in river habitat found 7 orders, 20 families, 40 genera, 47 species, 792 individuals with diversity index (H'=3.205), evenness index (E=0.833), richness index (R=6.892), and dominance index (0.075). Aerial insects in lake habitat found 8 orders, 18 families, 35 genera, 39 species, 692 individuals with diversity index (H'=2,906), evenness index (E=0.793), richness index (R=5.811), and dominance index (0.083).
 Keywords: dry land, aerial insect, species diversity, species richness, species evenness

Impact of Rice Cultivation Methods on Insect Pest Incidence and Their Management

Under the influence of fluctuating global climate scenario and limited resources of water availability, different methods of rice cultivation like System of rice intensification (SRI), Direct seeded rice (DSR), Alternate wetting and drying (AWD) and Aerobic rice have become popular as alternatives to conventional transplanting method. Due to these shifting cultivation situations, insect pest profiles have also undergone changes with associated influence on beneficial insects and other natural enemies. Multi-location studies carried out under All India Coordinated Rice Improvement Project (AICRIP) have revealed significantly less incidence of major pests like stem borers, planthoppers in SRI compared to normal rice transplanting method. Overall, the SRI method leads to more robust plant health with enhanced capacity to resist pest attacks. In case of DSR, AICRIP studies have consistently revealed higher incidence of all the insect pests in the normal transplanted method compared to DSR. However, few reports have indicated association of insect pest outbreaks with higher seed rate and plant densities. Limited studies have shown that AWD also has the potential to minimize the incidence of insect pests and diseases compared to irrigated rice. However, soil borne pests, particularly root-knot nematode can be more damaging under aerobic conditions. Field cum laboratory studies carried out at ICAR IIRR on impact of cultivation systems on the rich insect biodiversity in rice have revealed association of higher total abundance and greater richness of beneficial insect species with SRI management.

Diversity, Evenness, and Species Richness of Aerial Insects in Dry Land of Kefamenanu, North Central Timor, East Nusa Tenggara

This research was conducted to determine the diversity, richness, and evenness of aerial insects based on habitat characteristics in the dry land of Kefamenanu city, North Central Timor, East Nusa Tenggara. The research was conducted on three types of habitats, namely dry land, rivers, and lakes by purposive sampling method. Sampling was done by documenting specimens in each habitat, identifying, inventorying, and analyzing quantitatively to obtain data on species diversity, species richness, and species evenness. Results revealed that aerial insects in Kefamenanu City were found in 9 orders, 25 families, 44 genera, 54 species, and 1998 individuals in three habitat types with diversity index (H'=3,068), evenness index (E=0.774), richness index (R). = 6.974), and dominance index (0.074). Aerial insects in dryland habitats are found in 8 orders, 18 families, 32 genera, 32 species, 514 individuals with diversity index (H'=2.735), evenness index (E=0.789), richness index (R=4.966), and dominance index. (0.092). Aerial insects in river habitat found 7 orders, 20 families, 40 genera, 47 species, and 792 individuals with diversity index (H'=3.205), evenness index (E=0.833), richness index (R=6.892), and dominance index (0.075). Aerial insects in the lake habitat found 8 orders, 18 families, 35 genera, 39 species, 692 individuals with diversity index (H'=2,906), evenness index (E=0.793), richness index (R=5.811), and dominance index (0.083).

DIVERSITY AND DISTRIBUTION OF CLASS INSECTA FROM SELECTED AREA OF TUBA ISLAND RESERVE FOREST

Insects are ubiquitous and inhabit all types of ecosystems that include island ecosystems. A study on the diversity and distribution of Class Insecta was conducted at a selected forest area in Pulau Tuba using malaise traps. No insect study has been conducted at Pulau Tuba before. Three study sites namely forest fringe, middle forest, and inner forest were chosen. A total of 5883 specimens belonging to seven orders and 106 morphospecies of insects were collected. The orders identified were Blattodea, Coleoptera, Diptera, Hymenoptera, Hemiptera, Isoptera, and Lepidoptera. Diptera samples were the most found while Blattodea recorded the lowest number recorded. Shannon-Wiener Diversity Index (H’) showed that the inner forest had the highest diversity value with H’ = 0.53, followed by the forest fringe with H’ = 0.44, and the middle forest with H’ = 0.22. The Evenness Index (E’) and Margalef Richness Index (R’) also showed the highest value comes from the inner forest with E’ = 0.28 and R’ = 0.81 respectively. Kruskal-Wallis test showed that there was a significant difference in insect distribution across three study sites where P< 0.05. Overall, this study suggested that the diversity of Class Insecta at Pulau Tuba was low in the three locations confirming the low species richness of insects in the island forest ecosystem.

Fluctuating insect diversity, abundance and biomass across agricultural landscapes

Habitat destruction and deterioration of habitat quality caused a severe decline of biodiversity, such as insect diversity. In this study, we analyze insect diversity and biomass across agro-environments. We collected flying insects with 20 malaise traps across a landscape mosaic consisting of organic (eight traps) and conventional (four traps) farmland, as well as across agricultural land that has been recently converted from conventional to organic farming (eight traps). Sampling was conducted over 2 years, in 2019 and 2020, with in total 340 sampling events. We measured the dry weight of the captured organisms and identified species diversity by analyzing Operational Taxonomic Units (OTUs) and Barcode Index Numbers (BINs) via metabarcoding. The results obtained show temporal dynamics. The number of OTUs were always higher than the number of BINs. OTUs and BINs were moderately to highly correlated, while the number of OTUs and BINs were only moderately positively correlated with dry biomass. OTUs and BINs as well as biomass were highest in the recently transformed farmland if compared with pure organic and conventional farmland sites, which showed no significant differences in respect of insect diversity. OTU and BIN numbers but not the OTU/BIN ratio significantly decreased with increasing distance from the nearest forest fringe. The numbers of OTUs, BINs and the OTU/BIN proportion, as well as OTU and BIN/biomass proportions varied strongly over seasons, irrespective of agricultural practice. Based on our findings, we suggest to combine data on insect species richness and biomass measured over a period of time, to derive a largely complete and meaningful assessment of biodiversity for a specific region.

Conserving diversity in Irish plant-pollinator networks.

Beneficial insects provide valuable services upon which we rely, including pollination. Pollinator conservation is a global priority, and a significant concern in Ireland, where over half of extant bee species have declined significantly in recent decades. As flower‐visiting insects rely on flowering plants, one way to conserve and promote pollinator populations is to protect high‐quality habitat. We analyzed the structure of insect–flower interactions from multiple habitat categories in a large database of interactions from Ireland. Our primary goals were to compare spatial and temporal variation in Irish network structures, compare Irish networks to published networks from other countries, and provide evidence‐based recommendations for pollinator conservation in Ireland by identifying well‐visited plant species that may promote high pollinator diversity, abundance, and functional complementarity. Habitat types within Ireland differed substantially: seminatural grasslands had the highest pollinator species richness and largest number of unique pollinator species, while intensively managed habitats exhibited negative asymmetry (more plant than pollinator species). This negative asymmetry is notable because most plant–pollinator networks exhibit a positive asymmetry. Within intensively managed habitats, agricultural and urban habitats differed. Urban habitats had the highest number of non‐native plant species while agricultural habitats had the lowest pollinator species richness. We also found Irish networks varied across the growing season, where July had the highest plant and insect species richness. When comparing Irish networks to published networks from other countries, we found Irish networks had a higher ratio of plant species to pollinator species, and that this difference was most evident in agricultural habitats. This ratio means the typical network asymmetry (more pollinator than plant species) was flipped (more plant than pollinator species) in the Irish network. We conclude that conserving seminatural grasslands in Ireland will be an essential component of pollinator conservation and identify thirty‐five plant species important for restoring seminatural habitats.