Ants and their nests as indicators for industrial heavy metal contamination

Impact of environmental pollution on ant (Camponotus japonicus) development and labial gland disease

Metallic pollutants can have harmful impacts on ant morphology and physiology. We studied the occurrence of labial gland disease in Camponotus japonicus from two polluted areas (traffic pollution and industrial pollution) and one non-polluted area. We further analyzed the metal levels (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) and morphological characteristics (head width, body mass, and other morphological traits) of both diseased and healthy workers. Our results showed that labial gland disease was only present in polluted areas, indicating that pollution stress makes ants more vulnerable to infections. Our research revealed that diseased ants in polluted areas accumulate higher levels of metals in their bodies and have lower dry weight and residual body mass compared to healthy ants in non-polluted environments, negatively impacting their development. We evaluated the importance of these elements and found that Cu has the greatest impact on the health risk of C. japonicus. Our study underscores the significant impact of environmental pollution on ant morphology and physiology and raises concerns about the broader ecological implications.

Arthropods in landfills and their accumulation potential for toxic elements: A review

Landfills, as a source of potentially toxic elements (PTEs), pose a threat to the environment and human health. A literature review was conducted to explore the diversity of arthropods inhabiting solid waste landfills, as well as on the bioaccumulation of PTEs by arthropods. This review presents scientific papers over the last 20 years. Their importance in landfill ecosystems has been the subject of research; however, the issue of the accumulation of compounds such as toxic elements is emphasized only in a few studies. The bioaccumulation of PTEs was studied for 10 arthropod species that founded in landfills: Orthomorpha coarctata and Trigoniulus corallinus (class Diplopoda), Armadillidium vulgare and Trachelipus rathkii (class Malacostraca), the 6 species of the class Insecta - Zonocerus variegatus, Anacanthotermes ochraceus, Macrotermes bellicosus, Austroaeschna inermis, Calathus fuscipes and Harpalus rubripes.

Semi-arid's Unsung Heroes: Hymenoptera and the Vital Ecosystem Services Enabled by Encholirium spectabile, a Rupicolous Bromeliad in the Brazilian Semi-arid Region

The concept of Ecosystem Services (ES) recognizes the importance of natural ecosystems in supporting human well-being. Hymenoptera, a diverse group of insects including ants, bees, and wasps, play crucial roles in providing ESs. Despite their significance, the provision of ESs by Hymenoptera is often undervalued, leading to ecosystem degradation and loss of important services. This study focuses on the association between Hymenoptera and a rupicolous bromeliad species (Encholirium spectabile) and explores the ESs promoted directly and indirectly by these insects. The study area is located in the Caatinga region of Brazil, characterized by irregular rainfall and a dry season. The results show that Hymenoptera, particularly bees, ants, and wasps, provide a range of ESs including pollination, honey production, pest control, cultural symbolism, and educational value. These services are vital for plant reproduction, food production, and ecosystem functioning in both seasons; there are no differences in species richness between seasons, but rather in species composition. Understanding the importance of Hymenoptera for ESs is crucial for informing conservation and management practices to ensure the sustainability of natural ecosystems. The study highlights the need for conservation actions to protect the intricate ecological relationships between Hymenoptera and bromeliads, which indirectly support ESs by providing habitat and resources, especially during droughts when resources are scarce in the region. By recognizing the importance of bromeliads in supporting Hymenopteran communities, conservation efforts can focus on preserving these critical ecological interactions and maintaining ES provision.

Use of Honey Bees and Hive Products as Bioindicators to Assess Environmental Contamination in Targeted Areas of the Campania Region (Italy)

In recent years, biomonitoring has gained more attention, particularly when assessing the environmental health of significant areas, such as those near waste-to-energy facilities. These requirements coincide with the chance to detect environmental pollutants using sensitive organisms. Bees were shown to be quite effective in evaluating the presence of certain compounds by analyzing their associated matrices, such as pollen, honey, or wax. In our study, we employed the honey bee (Apis mellifera) as an indicator to initially monitor the vicinity of the waste-to-energy plant in Acerra, which is situated in the Campania region of Italy. The primary aim was to determine whether the facility was accountable for any environmental releases of dioxins or dioxin-like compounds. Then, we assessed the presence of additional pollutants in the same area, including trace elements, polycyclic aromatic hydrocarbons, and pesticides, released by human activities. To obtain further information about environmental quality, a second biomonitoring station was installed near the Caivano S.T.I.R. (Waste Shredding, Sifting, and Packaging Plant). The results showed the dioxin levels did not exceed predetermined limitations at the Acerra site, thus demonstrating the efficacy of the waste-to-energy facility and the bees' ability to detect the presence of other pollutants. Additionally, this biomonitoring system exhibited sensitivity to environmental variations, thereby enabling the evaluation of xenobiotic flux between two proximate zones and across temporal scales. This pioneering study suggests the advantages of utilizing bees to detect a wide range of contaminants, thereby providing valuable insights into environmental quality and potential health risks for both ecosystems and human populations.

Concentration of metals and metalloids in livers of birds of various foraging guilds collected during the autumn migration period in Poland

During migration, birds explore various habitats at stopover sites that differ in food resources and contamination levels. In this study, hepatic concentrations of 21 elements (metals and metalloids) in 11 species of birds, representing various foraging habitats (such as aquatic, aquatic/terrestrial, and terrestrial) and migration modes (migratory and sedentary) representing various foraging guilds (omnivores, piscivores, and molluscivores), were analyzed. The samples (N = 84) were collected during the autumn migration period in Poland. The concentrations of elements determined in this study exhibited high inter-species variability, reflecting the diversity in contamination levels depending on food resources used by specific bird groups. Many of the investigated individuals from different species showed exceeded levels of subclinical toxicity and moderate clinical poisoning due to Cd and Hg. Higher concentrations of As, Hg, and Ba and lower V concentrations were found in migratory birds as compared to sedentary birds. Species foraging in terrestrial habitat had different concentrations of some elements compared to aquatic and aquatic/terrestrial species. Some specific inter-species differences in hepatic elemental concentrations were found. Differences in elemental concentrations among various groups can primarily be attributed to their foraging guilds, with certain elements, particularly As, V, and Hg, playing a significant role in the dissimilarity of elemental concentrations between foraging habitat groups and migratory mode groups. The data collected confirmed the limited ability of As to enter ecosystem pathways. The results of this study contribute to understanding the year-round exposure of migratory birds to environmental contamination, which can have carry-over effects on their performance in wintering and breeding grounds.

Impact of Red Imported Fire Ant Nest-Building on Soil Properties and Bacterial Communities in Different Habitats

The red imported fire ant (Solenopsis invicta Buren) is a highly adaptable invasive species that can nest and reproduce in different habitat soils. We aimed to explore the adaptability of red imported fire ants in different habitats by analyzing changes in the physicochemical properties of nest soils and bacterial communities. Five habitat types (forest, tea plantation, rice field, lawn, and brassica field) were selected. The results showed that the pH of the nest soils increased significantly in all five habitats compared to the control soils of the same habitat. A significant increase in nitrogen content was detected in the nests. The Cr, Pb, Cu, and Ni levels were significantly reduced in the soils of the five habitats, due to nesting activities. Analysis of the composition and diversity of the soil microbial community showed that, although the richness and diversity of bacteria in the nest soils of red imported fire ants in the five habitats varied, the relative abundance of Actinobacteria significantly increased and it emerged as the dominant bacterial group. These results indicate that red imported fire ants modify the physicochemical properties of nest soils and bacterial communities to create a suitable habitat for survival and reproduction.

Comparative Analysis of Facial Coloration between Introduced and Source Populations of the Red Wood Ant Formica paralugubris

The variation in the typical black-reddish color of red wood ants (Formica rufa group) has been recently suggested as a good indicator of habitat quality, being dependent on environmental conditions. However, the relative contribution of external factors and heritability in shaping this trait is poorly investigated. In this study, we compared the facial coloration of workers from four introduced populations of Formica paralugubris with those of the two Alpine populations from which they had been taken. We used a Relative Warp Analysis to describe the variations in the shape of this trait. We expected each introduced population to be more similar to its population of origin if the color pattern was predominantly genetically determined. On the contrary, due to the considerable differences in habitat type and climate between the Alps and the Apennines, we expected to observe differences between the introduced population and their origin population if the coloration was mostly environmentally determined. With one exception that we discuss, the results showed that ants from the two source populations had different phenotypes, and that the introduced populations had a shape similar to the population of origin, suggesting a stable genetic background. Surprisingly, the habitat type seems to have a less clear effect, even if within-population differences suggest the influence of very localized environmental factors. Finally, we found that the facial coloration shape is affected by the ant’s size, a result in line with previous studies.

Sublethal Exposure to Cadmium Induces Chemosensory Dysfunction in Fire Ants

Ants easily accumulate cadmium (Cd) from the food web in terrestrial ecosystems. Cd contamination may cause olfactory dysfunction and consequently disorders in the social behavior of ants. To explore the molecular mechanism underlying the effect of Cd exposure on the chemosensory process of ants, we characterized the Cd-induced variations in the expression of genes involved in chemoreception and electrophysiological and behavioral sensitivity to semiochemicals by using the red imported fire ant, Solenopsis invicta, as a model system. As a result, Cd exposure increased Cd accumulation and decreased the survival rate of S. invicta. Cd exposure altered the expression profiles of odor binding protein genes of S. invicta (SiOBPs). Specifically, SiOBP15 protein expression was upregulated upon Cd exposure. Both SiOBP7 and SiOBP15 exhibited high binding affinities to limonene, nonanal, and 2,4,6-trimethylpyridine. S. invicta exposed to Cd showed less sensitive electrophysiological and behavioral response to the three chemicals but exhibited sensitive perception to undecane. Silencing of SiOBP7 and SiOBP15 abolished the behavioral response of S. invicta to nonanal and undecane, respectively, suggesting that SiOBP7 and SiOBP15 play essential roles in the chemoreception of S. invicta. In general, our results suggest that Cd contamination may interfere with olfactory signal transduction by altering the expression of SiOBPs, consequently evoking chemosensory dysfunction in fire ants.

Transfer of elements into boreal forest ants at a former uranium mining site

Ants can influence ecological processes, such as the transfer of elements or radionuclides, in several ways. For example, they redistribute materials while foraging and maintaining their nests and have an important role in terrestrial food webs. Quantitative data of the transfer of elements into ants is needed, e.g., for developing improved radioecological models. In this study, samples of red wood ants (genus Formica), nest material, litter and soil were collected from a former uranium mining site in Eastern Finland. Concentrations of 33 elements were analyzed by Inductively Coupled Plasma-Mass Spectroscopy/Optical Emission Spectroscopy. Estimated element concentrations in spruce needles were used as a proxy for studying the transfer of elements into ants via aphids because spruces host the most important aphid farms in boreal forests. Empirically determined organism/medium concentration ratios (CRs) are commonly used in radioecological models. Ant/soil CRs were calculated and the validity of the fundamental assumption behind the of use of CRs (linear transfer) was evaluated. Elements that accumulated in ants in comparison to other compartments were cadmium, potassium, phosphorus, sulfur, and zinc. Ant uranium concentrations were low in comparison to soil, litter, or nest material but slightly elevated in comparison to spruce needles. Ant element concentrations were quite constant regardless of the soil concentrations. Non-linear transfer models could therefore describe the soil-to-ant transfer better than conventional CRs.

Spatial Distribution of Heavy Metals in Near-Shore Marine Sediments of the Jeddah, Saudi Arabia Region: Enrichment and Associated Risk Indices

Red Sea coastal development has rapidly accelerated in recent decades that has led to a rise in the anthropogenic heavy metal levels in sediments. A total of 80 surficial sediment samples were collected from the shallow waters along the eastern Red Sea coast near Jeddah, Saudi Arabia. These samples were collected from three locations, designated as North, Middle and South of Jeddah, to assess the concentrations of six heavy metals: chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), and lead (Pb). The results showed that the concentrations (mg/kg) of these metals in the studied sediments follow this order: Pb (77.34 ± 150.59) > Mn (36.52 ± 37.72) > Zn (18.02 ± 23.94) > Cr (9.56 ± 5.81) > Cu (9.18 ± 13.67) > Ni (3.68 ± 4.54). The majority of the polluted sediments were recorded in the Middle and South locations. Pollution and enrichment indices such as Geo-accumulation indices (Igeo), Enrichment Factors (Ef), Contamination Factors (Cf), Pollution Load Indices (PLI), Potential Ecological Risk Indices (PERI) and Potential Toxicity Response Indices (RI) were calculated from the measured metals to establish baselines for the region and assess specific metal enrichments by location along the Jeddah coastline. The Igeo values showed that 30% of the Southern location stations are considered moderately to highly polluted. The Ef for all the studied sediments followed this order: Pb (extremely severe enrichment) > Zn > Cu > Cd > Cr (severe enrichment) > Ni (moderate enrichment).

Honey bees as biomonitors - Variability in the elemental composition of individual bees

Homogenized or pooled samples of honey bees are already used for monitoring of metal pollution in the environment for a couple of decades. This is the first study that analyzed the elemental composition of individual honey bees. One apiary with 21 hives was used to test in-hive and between-hive differences at the same location. Highest in-hive variability was observed for Al (14.1x), Li (10.3x), V (10.3x), As (8.9x) and Cd (7.9x). For the elements Cu, K, Mg, Na, P, S and Zn the smallest both in-hive (2.3x, 1.8x, 2.0x, 2.2x, 1.9x, 1.7x, 2.4x respectively) as well as between-hive variability (1.5x, 1.4x, 1.4x, 1.6x, 1.4x, 1.4x and 1.5x respectively) was observed. Nonetheless, between-hive variability was statistically significant for all the analyzed elements. We proved that these differences significantly influence comparison of element concentrations in bees from different locations. One hive from Mesić apiary had significantly lower concentrations of Al (hive 18: 18.6 mg kg^-1) and U (hive 1: 0.0013 mg kg^-1), while at the same time a different hive from the same apiary showed higher concentration of these elements (Al, hive 14: 125 mg kg^-1; U, hive 13: 0.012 mg kg^-1) compared to another location (thermal power plant, Al: 97 mg kg^-1, U: 0.0044 mg kg^-1). Therefore, when using honey bees as biomonitors, we recommend a larger number of hives to be sampled at each location to provide an adequate dataset for reliable interpretation of results. Comparing individual bee elemental concentrations, for Na, Mg, P, S, K, Fe, Cu, and Zn negative correlations were found between dry mass of a bee and concentrations of these elements. These negative correlations could be a consequence of higher honey or nectar content in some of the sampled bees. However, this should also be considered when using honey bees as bioindicators.

Cadmium exposure disrupts the olfactory sensitivity of fire ants to semiochemicals

Ants are eusocial insects and have evolved sensitive chemosensory systems for social communication. However, the effect of heavy metal contamination on the olfactory sensitivity of ants remains largely unknown. Here, we investigated the survival and olfactory response of Solenopsis invicta under cadmium (Cd) exposure. As a result, exposure to dietary Cd at different concentrations (100, 300 and 500 mg/L) caused higher Cd accumulation and lower survival of the ants compared with the control (0 mg/L). Cd exposure induced diverse expression patterns of odor binding protein genes (SiOBPs) in S. invicta antenna. Specifically, the expression of SiOBP4, SiOBP11, SiOBP12 and SiOBP16 was increased by 1.84-, 1.14-, 0.83- and 1.76-fold, respectively, at 300 mg/L Cd, while SiOBP7 and SiOBP9 were suppressed as Cd concentration increased. Electroantennography (EAG) and behavioral bioassays were performed to further evaluate the effect of Cd contamination on the olfactory sensitivity of S. invicta workers to 2, 4, 6-trimethylpyridine (TMP) and 2-ethyl-3,6(5)-dimethylpyrazine (EDP), the two frequent functional semiochemicals for S. invicta. The results showed that under no Cd exposure, S. invicta workers exhibited strong EAG response and apparent residing repellence to TMP and EDP, but Cd exposure suppressed EAG response and deprived the behavioral repellence to TMP and EDP of the workers, suggesting that Cd exposure decreases the olfactory sensitivity of S. invicta to these two functional semiochemicals. Further fluorescence competitive binding assay revealed that SiOBP7 had strong binding affinity to TMP and EDP, suggesting that the decrease in olfactory sensitivity may be attributed to the inhibitory effect of Cd exposure on SiOBP7. Overall, our results suggest that Cd exposure may not only directly decrease the survival of ants, but also affect their olfactory recognition.

Current permissible levels of metal pollutants harm terrestrial invertebrates

The current decline of invertebrates worldwide is alarming. Several potential causes have been proposed but metal pollutants, while being widespread in the air, soils and water, have so far been largely overlooked. Here, we reviewed the results of 527 observations of the effects of arsenic, cadmium, lead and mercury on terrestrial invertebrates. These four well-studied metals are considered as priorities for public health and for which international regulatory guidelines exist. We found that they all significantly impact the physiology and behavior of invertebrates, even at levels below those recommended as 'safe' for humans. Our results call for a revision of the regulatory thresholds to better protect terrestrial invertebrates, which appear to be more sensitive to metal pollution than vertebrates. More fundamental research on a broader range of compounds and species is needed to improve international guidelines for metal pollutants, and to develop conservation plans to protect invertebrates and ecosystem services.

Effects of native forest and human-modified land covers on the accumulation of toxic metals and metalloids in the tropical bee Tetragonisca angustula

The intensive shift on land cover by anthropogenic activities have led to changes in natural habitats and environmental contamination, which can ultimately impact and threat biodiversity and ecosystem services, such as pollination. The aim of this study was to evaluate the effect of native forest and human-modified land covers on the concentrations of chemical elements accumulated in the neotropical pollinator bee T. angustula. Eight landscapes, within an Ecological Corridor in the State of São Paulo, Brazil, with gradients of forest cover, spatial heterogeneity and varying land covers were used as sampling unities. Bees collected in traps or through actives searches had the concentration of 21 chemical elements determined by ICP-MS. Results show a beneficial effect of forested areas on the concentrations of some well-known toxic elements accumulated in bees, such as Hg, Cd, and Cr. Multivariate Redundancy Analysis (RDA) suggests road as the most important driver for the levels of Cr, Hg, Sb, Al, U, As, Pb and Pt and bare soil, pasture and urban areas as the landscape covers responsible for the concentrations of Zn, Cd, Mn, Mg, Ba and Sr in bees. The results reinforce the potential use of T. angustula bees as bioindicators of environmental quality and also show that these organisms are being directly affected by human land use, offering potential risks for the Neotropical ecosystem. Our study sheds light on how land covers (native forest and human-modified) can influence the levels of contaminants in insects within human-dominated landscapes. The generation of predictions of the levels of toxic metals and metalloids based on land use can both contribute to friendly farming planning as well as to support public policy development on the surrounding of protected areas and biodiversity conservation hotspots.

Assessment of legacy mine metal contamination using ants as indicators of contamination

Most legacy mines contributed to contamination of the environment before and after cessation of mining. Contamination from waste rock, slag and tailings can introduce large concentrations of metals and metalloids to the surface soil and downstream sediments. Since ants are able to accumulate metals in their bodies, we investigated the possibility of using the elemental compositions of ants as indicators of metals at legacy mines developed on ores rich in copper (Cu), zinc (Zn), arsenic (As), silver (Ag) and lead (Pb). Our results showed the concentrations of manganese (Mn) and Cu in ants were not significantly different between mine and reference samples and only Zn was significantly different between contaminated and reference areas. Crematogaster spp. and Notoncus spp. from reference areas accumulated larger concentrations of metals in their bodies compared to ants from the mine. Ants accumulated metals in different parts of their bodies. The abdomen was the main site for accumulation of Mn, iron (Fe) and Zn. Mandibles were only associated with accumulation of Zn. Copper and Pb showed no area of preferential accumulation and traces were detected in the whole body of the ants. Ants from five genera had similar regions for metal accumulation. The exoskeleton did not contribute to accumulation of metals; instead all metals were stored in internal organs. Not all genera were suitable for use as indicators; only Iridomyrmex spp. and Ochetellus spp. accumulated larger amount of metals in mine samples compared to reference samples.

Accumulation of metals in Lasius niger: Implications for using ants as bioindicators

The high capacity of many ant species to accumulate trace metals raises the question of whether the metal concentration in ants' bodies could reliably reflect the contamination of ecosystems. The idea of applying the metal accumulation in ants for bioindication purposes is tempting; however, the methods should consider that ants are unique organisms due to their social way of life. In this study, we describe the between-colony variation in the accumulation of Zn and Cd in workers of the common garden ant Lasius niger originated from the post-mining area of a zinc-and-lead smelter in southern Poland. We show that the accumulation of both metals differs significantly between colonies even within the same study site; at the maximum, we detected a three-fold difference in Zn accumulation and a six-fold difference in Cd. The results showed that in the study area, the capacity of L. niger to accumulate metals is highly colony-specific. If future studies on other ant species concur with our findings, this may suggest that incorporating the between-colony variation of metal accumulation in prospective bioindication protocols would provide a higher accuracy of the assessments on the contamination of impacted environments. We suggest that using ants for bioindication should be preceded by preliminary studies to assess representative samples of colonies that could reliably indicate the contamination of the investigated area.

Benefits of insect colours: a review from social insect studies

Insect colours assist in body protection, signalling, and physiological adaptations. Colours also convey multiple channels of information. These channels are valuable for species identification, distinguishing individual quality, and revealing ecological or evolutionary aspects of animals' life. During recent years, the emerging interest in colour research has been raised in social hymenopterans such as ants, wasps, and bees. These insects provide important ecosystem services and many of those are model research organisms. Here we review benefits that various colour types give to social insects, summarize practical applications, and highlight further directions. Ants might use colours principally for camouflage, however the evolutionary function of colour in ants needs more attention; in case of melanin colouration there is evidence for its interrelation with thermoregulation and pathogen resistance. Colours in wasps and bees have confirmed linkages to thermoregulation, which is increasingly important in face of global climate change. Besides wasps use colours for various types of signalling. Colour variations of well chemically defended social insects are the mimetic model for unprotected organisms. Despite recent progress in molecular identification of species, colour variations are still widely in use for species identification. Therefore, further studies on variability is encouraged. Being closely interconnected with physiological and biochemical processes, insect colouration is a great source for finding new ecological indicators and biomarkers. Due to novel digital imaging techniques, software, and artificial intelligence there are emerging possibilities for new advances in this topic. Further colour research in social insects should consider specific features of sociality.

Facing the threat: common yellowjacket wasps as indicators of heavy metal pollution

We investigated the common wasp, Vespula vulgaris as a bioindicator and biomonitor of metals in the industrial area. Using traps, we collected 257 yellowjackets along a pollution gradient in the Harjavalta Cu-Ni smelter in Southwest Finland. Our method detected metal elements such as arsenic (As), cobalt (Co), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), zinc (Zn), and mercury (Hg) in wasps. The data analyses revealed V. vulgaris can be a proper indicator for As, Cd, Co, Cu, Ni, and Pb, rather than for Fe and Zn contamination. Body burdens of As, Cd, Co, Cu, Ni, and Pb decreased with an increase in distance from smelter. Enrichment factor (EF) followed the pattern Pb ˃ Cd ˃ As ˃ Co ˃ Cu ˃ Ni. The highest bioaccumulation (BAF) values were revealed for Cd (5.9) and the lowest for Pb (0.1). Specially designed software (WaspFacer) allowed revealing body burdens of As, Cd, Co, Cu, Ni, and Pb to be associated with rather smaller than more asymmetric facial colour markings in yellowjackets. These results add to the body of literature on how heavy metal contaminants can have tangible phenotypic effects on insects and open future opportunities for using wasps as indicators of metal pollution.

The ecosystem services provided by social insects: traits, management tools and knowledge gaps

Social insects, i.e. ants, bees, wasps and termites, are key components of ecological communities, and are important ecosystem services (ESs) providers. Here, we review the literature in order to (i) analyse the particular traits of social insects that make them good suppliers of ESs; (ii) compile and assess management strategies that improve the services provided by social insects; and (iii) detect gaps in our knowledge about the services that social insects provide. Social insects provide at least 10 ESs; however, many of them are poorly understood or valued. Relevant traits of social insects include high biomass and numerical abundance, a diversity of mutualistic associations, the ability to build important biogenic structures, versatile production of chemical defences, the simultaneous delivery of several ESs, the presence of castes and division of labour, efficient communication and cooperation, the capacity to store food, and a long lifespan. All these characteristics enhance social insects as ES providers, highlighting their potential, constancy and efficiency as suppliers of these services. In turn, many of these traits make social insects stress tolerant and easy to manage, so increasing the ESs they provide. We emphasise the need for a conservation approach to the management of the services, as well as the potential use of social insects to help restore habitats degraded by human activities. In addition, we stress the need to evaluate both services and disservices in an integrated way, because some species of social insects are among the most problematic invasive species and native pests. Finally, we propose two areas of research that will lead to a greater and more efficient use of social insects as ES providers, and to a greater appreciation of them by producers and decision-makers.

Pollutants and Their Interaction with Diseases of Social Hymenoptera

Many insect species, including social insects, are currently declining in abundance and diversity. Pollutants such as pesticides, heavy metals, or airborne fine particulate matter from agricultural and industrial sources are among the factors driving this decline. While these pollutants can have direct detrimental effects, they can also result in negative interactive effects when social insects are simultaneously exposed to multiple stressors. For example, sublethal effects of pollutants can increase the disease susceptibility of social insects, and thereby jeopardize their survival. Here we review how pesticides, heavy metals, or airborne fine particulate matter interact with social insect physiology and especially the insects’ immune system. We then give an overview of the current knowledge of the interactive effects of these pollutants with pathogens or parasites. While the effects of pesticide exposure on social insects and their interactions with pathogens have been relatively well studied, the effects of other pollutants, such as heavy metals in soil or fine particulate matter from combustion, vehicular transport, agriculture, and coal mining are still largely unknown. We therefore provide an overview of urgently needed knowledge in order to mitigate the decline of social insects.

Comprehensive Resource Utilization of Waste Using the Black Soldier Fly (Hermetia illucens (L.)) (Diptera: Stratiomyidae)

The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), is a saprophytic insect that can digest organic wastes, such as animal manure, plant residues, and food and agricultural wastes. In the degradation process, organic wastes are converted into protein, grease, and polypeptides, which can be applied in medicine, the refining of chemicals, and the manufacturing of feedstuffs. After their conversion by the H. illucens, organic wastes not only become useful but also environmentally friendly. To date, the H. illucens has been widely used to treat food waste and to render manure harmless. The protein and grease obtained via this insect have been successfully used to produce livestock feed and biodiesel. In this article, the biological characteristics, resource utilization of protein and grease, and environmental functions of the H. illucens are summarized. This article provides a theoretical basis for investigating potential applications of the H. illucens.