The State of the World's Insects Eggleton, Paul
Annual review of environment and resources,
10/2020, Letnik:
45, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This article reviews the present state of insects, describing their taxonomic position, cost, and value as well as the threats to their well-being. Insects are an important source of both ecosystem ...services and ecosystem disservices. Recent studies have indicated a worrying decline in insect species, especially in flying insects in the northern temperate region, and this has spawned much media attention. Some decline has occurred, it is clear, due to agricultural intensification, urbanization, overuse of pesticides, and global climate change. A decline would seriously affect the ecosystem services that insects provide. However, there is too little data to warrant the belief that all insects are declining everywhere. There is a pressing need for more basic research on insect diversity in the context of a changing world.
ABSTRACT
Animal interactions play an important role in understanding ecological processes. The nature and intensity of these interactions can shape the impacts of organisms on their environment. ...Because ants and termites, with their high biomass and range of ecological functions, have considerable effects on their environment, the interaction between them is important for ecosystem processes. Although the manner in which ants and termites interact is becoming increasingly well studied, there has been no synthesis to date of the available literature. Here we review and synthesise all existing literature on ant–termite interactions. We infer that ant predation on termites is the most important, most widespread, and most studied type of interaction. Predatory ant species can regulate termite populations and subsequently slow down the decomposition of wood, litter and soil organic matter. As a consequence they also affect plant growth and distribution, nutrient cycling and nutrient availability. Although some ant species are specialised termite predators, there is probably a high level of opportunistic predation by generalist ant species, and hence their impact on ecosystem processes that termites are known to provide varies at the species level. The most fruitful future research direction will be to evaluate the impact of ant–termite predation on broader ecosystem processes. To do this it will be necessary to quantify the efficacy both of particular ant species and of ant communities as a whole in regulating termite populations in different biomes. We envisage that this work will require a combination of methods, including DNA barcoding of ant gut contents along with field observations and exclusion experiments. Such a combined approach is necessary for assessing how this interaction influences entire ecosystems.
Termites are instantly recognizable mound-builders and house-eaters: their complex social lifestyles have made them incredibly successful throughout the tropics. Although known as 'white ants', they ...are not ants and their relationships with other insects remain unclear. Our molecular phylogenetic analyses, the most comprehensive yet attempted, show that termites are social cockroaches, no longer meriting being classified as a separate order (Isoptera) from the cockroaches (Blattodea). Instead, we propose that they should be treated as a family (Termitidae) of cockroaches. It is surprising to find that a group of wood-feeding cockroaches has evolved full sociality, as other ecologically dominant fully social insects (e.g. ants, social bees and social wasps) have evolved from solitary predatory wasps.
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•Anaplecta is close to (potential sister of) Cryptocercidae+Isoptera, does not belong in Blaberoidea.•Corydiidae is paraphyletic with respect to Nocticolidae.•Wood-feeding may have ...been important in the development of isopteran eusociality.•Extant Blattodea diversity dates back 257mya (upper Permian).•Splits between major blattodean lineages no later than 200mya (end of Triassic).
Termites (Isoptera) offer an alternative model for the development of eusociality which is not dependent on a high degree of relatedness as found between sisters in hymenopterans (bees, wasps, ants). Recent phylogenetic studies have established that termites belong within the cockroaches as sister to the subsocial Cryptocercidae. Cryptocercidae shares several important traits with termites, thus we need to understand the phylogenetic position of Cryptocercidae+Isoptera to determine how these traits evolved. However, placement of Cryptocercidae+Isoptera is still uncertain. We used both molecular (12S, 16S, COII, 18S, 28S, H3) and morphological characters to reconstruct the phylogeny of Dictyoptera. We included all previously suggested sister groups of Cryptocercidae+Isoptera as well as taxa which might represent additional major cockroach lineages. We used Bayes factors to test different sister groups for Cryptocercidae+Isoptera and assessed character support for the consensus tree based on morphological characters and COII amino acid data. We used the molecular data and fossil calibration to estimate divergence times. We found the most likely sister groups of Cryptocercidae+Isoptera to be Tryonicidae, Anaplecta or Tryonicidae+Anaplecta. Anaplecta has never previously been suggested as sister group or even close to Cryptocercidae+Isoptera, but was formerly placed in Blaberoidea as sister to the remaining taxa. Topological tests firmly supported our new placement of Anaplecta. We discuss the morphological characters (e.g. retractable genitalic hook) that have contributed to the previous placement of Anaplecta in Blaberoidea as well as the factors that might have contributed to a parallel development of genitalic features in Anaplecta and Blaberoidea. Cryptocercidae+Isoptera is placed in a clade with Tryonicidae, Anaplecta and possibly Lamproblattidae. Based on this, we suggest that wood-feeding, and the resultant need to conserve nitrogen, may have been an important factor in the development of termite eusociality. Nocticolidae was placed as sister group to Latindia+Paralatindia (both Corydiidae), this clade was in turn placed as sister group to the remaining Corydiidae. The Nocticolidae+Corydiidae clade is supported by both morphological and COII amino acid changes. Our divergence time estimates placed the split between Mantodea and Blattodea at 273mya (middle Permian) and the splits between the major blattodean lineages no later than 200mya (end of Triassic).
1. Ants are diverse and abundant, especially in tropical ecosystems. They are often cited as the agents of key ecological processes, but their precise contributions compared with other organisms have ...rarely been quantified. Through the removal of food resources from the forest floor and subsequent transport to nests, ants play an important role in the redistribution of nutrients in rainforests. This is an essential ecosystem process and a key energetic link between higher trophic levels, decomposers and primary producers. 2. We used the removal of carbohydrate, protein and seed baits as a proxy to quantify the contribution that ants, other invertebrates and vertebrates make to the redistribution of nutrients around the forest floor, and determined to what extent there is functional redundancy across ants, other invertebrate and vertebrate groups. 3. Using a large-scale, field-based manipulation experiment, we suppressed ants from c.1 ha plots in a lowland tropical rainforest in Sabah, Malaysia. Using a combination of treatment and control plots, and cages to exclude vertebrates, we made food resources available to: (i) the whole foraging community, (ii) only invertebrates and (iii) only non-ant invertebrates. This allowed us to partition bait removal into that taken by vertebrates, non-ant invertebrates and ants. Additionally, we examined how the non-ant invertebrate community responded to ant exclusion. 4. When the whole foraging community had access to food resources, we found that ants were responsible for 52% of total bait removal whilst vertebrates and non-ant invertebrates removed the remaining 48%. Where vertebrates were excluded, ants carried out 61% of invertebrate-mediated bait removal, with all other invertebrates removing the remaining 39%. Vertebrates were responsible for just 24% of bait removal and invertebrates (including ants) collectively removed the remaining 76%. There was no compensation in bait removal rate when ants and vertebrates were excluded, indicating low functional redundancy between these groups. 5. This study is the first to quantify the contribution of ants to the removal of food resources from rainforest floors and thus nutrient redistribution. We demonstrate that ants are functionally unique in this role because no other organisms compensated to maintain bait removal rate in their absence. As such, we strengthen a growing body of evidence establishing ants as ecosystem engineers, and provide new insights into the role of ants in maintaining key ecosystem processes. In this way, we further our basic understanding of the functioning of tropical rainforest ecosystems.
Forested tropical landscapes around the world are being extensively logged and converted to agriculture, with serious consequences for biodiversity and potentially ecosystem functioning. Here we ...investigate associations between habitat disturbance and functional diversity of ants and termites—two numerically dominant and functionally important taxa in tropical rain forests that perform key roles in predation, decomposition, nutrient cycling and seed dispersal. We compared ant and termite occurrence and composition within standardised volumes of soil and dead wood in old growth forest, logged forest and oil palm plantation in Sabah, Malaysian Borneo. Termites occurred substantially less frequently in converted habitats than in old growth forest, whereas ant occurrences were highest in logged forest and lowest in old growth forest. All termite feeding groups had low occurrence in disturbed habitats, with soil feeders occurring even less frequently than wood feeders. Ant functional groups showed more variable associations, with some opportunist and behaviourally dominant groups being more abundant in degraded habitats. The importance of ants and termites in tropical ecosystems and such differing patterns of assemblage variation suggest that ecosystem functioning may be significantly altered in converted habitats.
A homologue of binding immunoglobulin protein/BiP-IRL201805 alters the function of immune cells in pre-clinical in vivo and in vitro studies. The aim of the study was to select biomarkers that ...clearly delineate between RA patients who respond to IRL201805 and placebo patients and reveal the immunological mode of action of IRL201805 driving the extended pharmacodynamics observed in responding patients. Biomarkers that distinguished between responding patients and placebo patients included downregulation of serum interferon-γ and IL-1β; upregulation of anti-inflammatory mediators, serum soluble CTLA-4, and intracellular monocyte expression of IDO; and sustained increased CD39 expression on CD3
CD4
CD25
CD127
regulatory T cells. In the responding patients, selected biomarkers verified that the therapeutic effect could be continuous for at least 12 weeks post-infusion. In secondary co-culture, pre-infusion PBMCs cultured 1:1 with autologous PBMCs, isolated at later time-points during the trial, showed significantly inhibited IL-6 and IL-1β production upon anti-CD3/CD28 stimulation demonstrating IRL201805 alters the function of immune cells leading to prolonged pharmacodynamics confirmed by biomarker differences. IRL201805 may be the first of a new class of biologic drug providing long-term drug-free therapy in RA.
Endoplasmic reticulum (ER) chaperones (e.g., calreticulin, heat shock proteins, and isomerases) perform a multitude of functions within the ER. However, many of these chaperones can translocate to ...the cytosol and eventually the surface of cells, particularly during ER stress induced by e.g., drugs, UV irradiation, and microbial stimuli. Once on the cell surface or in the extracellular space, the ER chaperones can take on immunogenic characteristics, as mostly described in the context of cancer, appearing as damage-associated molecular patterns recognized by the immune system. How ER chaperones relocate to the cell surface and interact with other intracellular proteins appears to influence whether a tumor cell is targeted for cell death. The relocation of ER proteins to the cell surface can be exploited to target cancer cells for elimination by immune mechanism. Here we evaluate the evidence for the different mechanisms of ER protein translocation and binding to the cell surface and how ER protein translocation can act as a signal for cancer cells to undergo killing by immunogenic cell death and other cell death pathways. The release of chaperones can also exacerbate underlying autoimmune conditions, such as rheumatoid arthritis and multiple sclerosis, and the immunomodulatory role of extracellular chaperones as potential cancer immunotherapies requires cautious monitoring, particularly in cancer patients with underlying autoimmune disease.
Five finely preserved termites from the mid‐Cretaceous (Cenomanian) amber of Myanmar provide new information allowing a reanalysis of the phylogeny of basal termites. The Mastotermitidae family is ...recovered as monophyletic, and a redefined Hodotermitidae sensu lato is also monophyletic to include Archotermopsidae, Hodotermitidae and Stolotermitidae. Such a phylogenetic relationship agrees with the results from previous molecular phylogeny. Alongside these findings, there are many taxa that can only be shown to be termites with no other phylogenetically informative data. These form a comb of ‘grade groups’ emerging in the Late Jurassic. The new amber specimens are described as two new species. Anisotermes xiai gen. et sp.n. is described from multiple castes and has symplesiomorphic characteristics: large body size, a broad pronotum, well‐developed reticulated veins, and a large anal lobe of the hindwings. It shares wing features with the other new species, Mastotermes monostichus sp.n. Both new taxa are assigned to the Mastotermitidae, as they are shown to have synapomorphies that unite the family.
This published work has been registered on ZooBank,
http://zoobank.org/urn:lsid:zoobank.org:pub:1AD5CECA‐27B7‐48D5‐88DC‐CEC5150962D7.
The oldest known mastotermitids, Anisotermes xiai gen. et sp.n. and Mastotermes monostichus sp.n., are described from multiple castes and wings, respectively.
A reanalysis of the phylogeny of the basal termites indicates that Mastotermitidae is a monophyly.
Hodotermitidae sensu lato is monophyletic to include Archotermopsidae, Hodotermitidae and Stolotermitidae.
Objective
To examine the potential of chronic severe bacterial infection to generate rheumatoid factor (RF) and anti–citrullinated protein antibodies (ACPAs), by studying patients with bronchiectasis ...(BR) alone and BR patients with rheumatoid arthritis (BR/RA).
Methods
We studied 122 patients with BR alone, 50 patients with BR/RA, and 50 RA patients without lung disease, as well as 87 patients with asthma and 79 healthy subjects as controls. RF levels were measured using an automated analyzer, and cyclic citrullinated peptide 2 (CCP‐2) was used to detect ACPAs. The fine specificities of citrullinated α‐enolase peptide 1 (CEP‐1), Cit‐vimentin, and Cit‐fibrinogen to their arginine‐containing control peptides (arginine‐containing α‐enolase peptide 1 REP‐1, vimentin, and fibrinogen) were measured by enzyme‐linked immunosorbent assay.
Results
Among the BR patients and control subjects, 39% and 42%, respectively, were ever‐smokers. The frequency of RF positivity in serum was increased in BR patients compared with controls (25% versus 10%), as were the frequencies of antibodies to CCP‐2 (5% versus 0%), CEP‐1 (7% versus 4%), Cit‐vimentin (7% versus 4%), and Cit‐fibrinogen (12% versus 4%), although only the differences for RF and Cit‐fibrinogen were significant (P < 0.05). We observed a corresponding increase in the frequency of antibodies to the arginine‐containing control peptides in BR patients compared with controls (for REP‐1, 19% versus 4% P < 0.01; for vimentin, 16% versus 4% P < 0.05), demonstrating that the ACPA response in patients with BR is not citrulline specific. The lack of citrulline specificity was further confirmed by absorption studies. In BR/RA patients, all ACPA responses were highly citrulline specific.
Conclusion
Bronchiectasis is an unusual but potent model for the induction of autoimmunity in RA by bacterial infection in the lung. Our study suggests that the ACPA response is not citrulline specific during the early stages of tolerance breakdown but becomes more specific in patients with BR in whom BR/RA develops.
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