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Colleterial glands of female insects are accessory glands responsible for producing secretions associated with egg-laying. Within Dictyoptera, they synthesize compounds of the ootheca. However, their morphology and role in termites are poorly understood. Here, we compared the morphology, development, and secretory activity of the colleterial glands between non- and egg-laying females of the pest termite Coptotermes gestroi under light and transmission electron microscopy. We also provide the first description of these glands for Rhinotermitidae. The glands are paired, divided into anterior and posterior units, which join in a common duct via basal trunks. They are highly developed within egg-laying females, especially the posterior gland, secreting glycoproteins to lubricate the genital chamber and/or stick the eggs together. Ultrastructure revealed glandular epithelia composed of bicellular units of Class 3, whose secretory activity varied between groups and units. Posterior gland of egg-laying females showed richness of mitochondria, rough endoplasmic reticulum, and secretory vesicles, including electron-dense secretory granules, indicating synthesis and transport of contents, especially proteins. The basal trunks were enfolded by muscles, supporting their role in conducting secretion. Morphophysiological modifications occur in the colleterial glands as females mature and lay eggs, and the mechanisms underlying the secretory cycle of the glands are discussed.

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Termites are among the insects that consume lichens and may be potential dispersers of these symbionts. This study evaluated the vitality of photobionts and mycobionts after passing through the digestive tract of Constrictotermes cyphergaster. The percentage of live and dead algae was verified throughout the alimentary canal of 450 workers, originating from five sampled colonies in the Caatinga Dry Forest, NE, Brazil. A progressive growth in algae mortality was observed in the crop, paunch and rectum, however more than 40% of the algae found in faeces presented signs of vitality. Photobiont morphology was different between cells extracted from thallus in natura and algae present in termite faeces. The photobiont cells presented more shrunken cytoplasms after passing through the alimentary canal of C. cyphergaster. There was also an increase between the cell wall space and the cytoplasm membrane of algae found in the termite faecal pellets. Only four broken spores were found in the intestine, which made the vitality analysis unfeasible for these cells. The record of photobiont vitality in termite faecal pellets is indicative of endozoochoric dispersal, suggesting that this relationship between insects and lichens extends beyond a trophic interaction.

Os térmitas estão entre os insetos consumidores de liquens e representam um potencial dispersor desses simbiontes. Este estudo avaliou a vitalidade de fotobiontes e micobiontes depois de terem passado pelo trato digestivo de Constrictotermes cyphergaster. O percentual de algas vivas e mortas foi verificado ao longo do canal alimentar de 450 operários, oriundos de cinco colônias amostradas em Caatinga Dry Forest, NE, Brazil. Um crescimento progressivo na mortalidade das algas foi observado no sentido papo, pança e reto, porém mais de 40% das algas presentes nas fezes apresentaram sinais de vitalidade. A morfologia dos fotobiontes foi diferente entre células extraídas de talos in natura e algas presentes nas fezes dos térmitas. As células do fotobionte apresentaram seu citoplasma mais encolhido, após a passagem pelo canal alimentar de C. cyphergaster. Também houve um aumento entre o espaço da parede celular e a membrana do citoplasma das algas encontradas nas pelotas fecais dos térmitas. Apenas quatro esporos quebrados foram encontrados no intestino dos cupins, o que inviabilizou a análise de vitalidade dessas células. O registro da vitalidade de fotobiontes nas pelotas fecais dos térmitas é um indicativo de dispersão endozoocórica, remetendo que a relação entre esses insetos e os liquens pode ir além de uma interação trófica.

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Research on food finding by pest termites can be used to inform the development of techniques to control their population; however, there is a paucity of information available on the foraging behavior of Nasutitermes corniger, an urban pest in South America. In the present study, we analyzed the effect of the distance between the nest and food on the exploration and recruitment of N. corniger during foraging behavior under laboratory conditions. Nests containing mature colonies were collected in the field and placed in a glass cube connected to a test arena (50.0 × 40.0 cm) in which Eucalyptus grandis blocks were supplied at three different distances: 10, 20 and 30 cm. In each test, the occurrence of the following events were recorded: initial exploitation, initial recruitment, and mass worker recruitment. Individuals in the blocks were counted at the end of each test and divided into the total number of recruited termites, recruited workers, consuming workers and recruited soldiers. Each test lasted 60 minutes and was repeated with 20 colonies. Nasutitermes corniger foragers showed the three behavioral events of interest at all three distances. The occurrences of initial exploitation and initial recruitment, the latency of the three events and the number of foragers were not affected by the distance between the nest and food. The occurrence of mass worker recruitment was the only event affected by this distance, with higher recruitment at shorter distances.

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For our knowledge, the roadside soils end up being the deposit of various residues discarded by drivers or passengers, plus, that coming from the runoff of rainwater. Basically, we do not know the impacts that this pollution causes on animals which inhabit these environments. Thus, in this study, our objective was to evaluate how the presence of plastic microfibers (MPFs), organic compounds and heavy metals affect the redox and cholinesterase homeostasis of mound-building termite [Cornitermes cumulans (workers) adults]. As a result, we noticed that MPFs were present in all sampled areas, being higher in road area (RA). Regardless of the presence of these pollutants, animals sampled in the RA were those in which we observed greater production of reactive oxygen species (ROS), hydrogen peroxide (H2O2) and nitric oxide (NO) (via nitrite), whose higher activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), was not able to counterbalance the oxidative stress suggested by the evaluated biomarkers. Moreover, we observed increase in acetylcholinesterase (AChE) activity in these same animals, which suggests a cholinesterasic effect. Such alterations were positively correlated with the contamination of soil samples by Cd, Pb, Zn, Fe and Cu, as well as with the presence of the 11,10-guaiane-type sesquiterpenoid compound, identified only in the RA. Thus, our unique study reveals that the contamination of roadside soils constitutes an additional environmental stressor to populations of C. cumulans, which reinforces the need for greater attention and further investigation to be given to the pollution of these environments.

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We report, for the first time, the presence of the termite Ereymatermes rotundiceps Constantino, 1991 as an inquiline of the termite Embiratermes neotenicus (Holmgren, 1906) in the Colombian Amazon, and provide new morphometric information on the species. Soldiers of E. rotundiceps were collected in epigeal nests built by E. neotenicus in pastures during the transition from the dry to the rainy season. The association between host and inquiline termites does not seem to be antagonistic, but the relationship between these two species still needs to be clarified.(AU)

Reportamos por primera vez la presencia de la termita Ereymatermes rotundiceps Constantino, 1991 como inquilino de Embiratermes neotenicus (Holmgren, 1906) en la Amazonia Colombiana y aportamos nueva información morfométrica para las especies. Soldados de E. rotundiceps fueron recolectados en nidos epigeos construidos por E. neotenicus en pasturas durante la transición de la estación seca a la lluviosa. La asociación entre las termitas hospederas e inquilinas parece no ser antagónica, sin embargo, las relaciones entre estas dos especies están aún por esclarecer.(AU)

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The variation in altitude drives the richness and density of species in tropical ecosystems. The diversity and richness of termites are influenced by the variations in temperature, humidity, and soil properties according to altitude elevation. This is well known for rainy forests and little information is found for semiarid areas of Brazil. In this study, we aimed to identify species richness and encounters density of termites in a hill inserted in the Caatinga Brazilian forest. We found variation in the composition of species as a function of altitude (in a comparison of top and foot of the hill) and in periods of the wet and dry, with an increase in the season wet. The increase the diversity in this period and altitude elevations can be explained by the increases in humidity after rainfalls and maintenance of temperature enabled by the conditions in the hill's top. Our findings provide valuable information regarding termite diversity in semiarid areas as a function of elevation and contribute to other studies that are expanding our understanding of how elevation can affect these organisms.

As variações na altitude modulam a riqueza e densidade de espécies em ecossistemas tropicais. A densidade e riqueza de cupins são influenciadas por variações na temperatura, umidade, e propriedades do solo de acordo com a elevação da altitude. Isso é bem conhecido para florestas úmidas, e pouca informação é encontrada para áreas semiáridas do Brasil. Neste estudo, tivemos por objetivo identificar a riqueza de espécies e densidade de encontros de cupins em uma serra localizada em floresta brasileira de Caatinga. Encontramos variação na composição de espécies em função da altitude (em comparação de topo e base da serra), e em períodos de seca e chuva, com aumento na estação chuvosa. O aumento na diversidade nesse período e nas elevações da altitude pode ser explicada pelo aumento na umidade após as chuvas, e a manutenção da temperatura propiciada pelas condições do topo da serra. Nossos dados fornecem informações importantes a respeito da diversidade de cupins no semiárido em função de elevações na altitude, e contribui com outros estudos que expandem o nosso conhecimento a respeito de como a elevação pode afetar esses organismos.

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Amazonian rainforests, once thought to be pristine wilderness, are increasingly known to have been widely inhabited, modified, and managed prior to European arrival, by human populations with diverse cultural backgrounds. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by pre-Columbian societies with sedentary habits. Much is known about the chemistry of these soils, yet their zoology has been neglected. Hence, we characterized soil fertility, macroinvertebrate communities, and their activity at nine archeological sites in three Amazonian regions in ADEs and adjacent reference soils under native forest (young and old) and agricultural systems. We found 673 morphospecies and, despite similar richness in ADEs (385 spp.) and reference soils (399 spp.), we identified a tenacious pre-Columbian footprint, with 49% of morphospecies found exclusively in ADEs. Termite and total macroinvertebrate abundance were higher in reference soils, while soil fertility and macroinvertebrate activity were higher in the ADEs, and associated with larger earthworm quantities and biomass. We show that ADE habitats have a unique pool of species, but that modern land use of ADEs decreases their populations, diversity, and contributions to soil functioning. These findings support the idea that humans created and sustained high-fertility ecosystems that persist today, altering biodiversity patterns in Amazonia.

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As the number or density of interacting individuals in a social group increases, a transition can develop from uncorrelated and disordered behavior of the individuals to a collective coherent pattern. We expand this observation by exploring the fine details of termite movement patterns to demonstrate that the value of the scaling exponent µ of a power law describing the Lévy walk of an individual is modified collectively as the density of animals in the group changes. This effect is absent when termites interact with inert obstacles. We also show that the network of encounters and interactions among specific individuals is selective, resembling a preferential attachment mechanism that is important for social networking. Our data strongly suggest that preferential attachments, a phenomenon not reported previously, and favorite interactions with a limited number of acquaintances are responsible for the generation of Lévy movement patterns in these social insects.

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The composition of chemical weaponry of termite soldiers show interspecific and intraspecific variation. However, spatial effects on the qualitative and quantitative compositions of these substances in Neotropical termites are poorly known. Hexane extracts of heads and the defensive secretion of soldiers of Constrictotermes cyphergaster from four localities in Northeast Brazil were analyzed by gas chromatography and mass spectrometry. Chemical analysis allowed the detection of 54 compounds from the head extract and from the direct extraction of the defensive secretion of soldiers, and the percentage of common substances and the presence of exclusive substances varied depending on the spatial distance between colonies. The profile of the chemical armament of soldiers consists basically of terpenoids: monoterpenes (45.53%-71.97 - for head extract and 57.41% - 78.56 for secretion) and sesquiterpenes (19.69% - 35.78% for head extract and 18.41% - 33.31%for secretion). In general, the main component of the chemical arsenal, regardless of the methodology used for extraction, was α-pinene (27.98-50.44%). Two chemotypes were identified based on chemical differences between populations of ecoregions with distinct spatial-environmental and climate characteristics: (1) α-pinene <33%; (2) α-pinene >33% for both extracts (head and secretion). The results reveal a similar pattern of chemical differentiation for soldiers in both extracts (head and secretion), with increasing differences as a function of distance between the analyzed colonies.

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Giardia comprises one genus with several morphologically distinct species described in mammals (including humans, marsupials, rodents), birds, and amphibians. This group of protists provokes diarrhoea diseases in humans and animals worldwide. Transmission of the parasite occurs through the faecal-oral route. Regarding the presence of Giardia in invertebrates, some works have shown that flies can transmit Giardia cysts by contact and transport between contaminated faeces and food. In this way, flies would eventually transmit this parasite. To date, Giardia's presence in the gut of other invertebrates has not been described in the literature. Here we show by first time, using scanning electron microscopy, the presence of Giardia-like trophozoites in the gut of termite Heterotermes tenuis. Two groups of Giardia were found based exclusively on the size and the flange shape of the protozoa: one presented eight flagella, a ventral disc, size, and shape very similar to Giardia intestinalis. In contrast, other cells were smaller and showed some differences in the external morphology. We cannot exclude the possibility that they correspond to the same species and that these differences result from protozoan heterogeneity.

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Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes which catalyze the oxidative cleavage of polysaccharides. LPMOs belonging to family 15 in the Auxiliary Activity (AA) class from the Carbohydrate-Active Enzyme database are found widespread across the Tree of Life, including viruses, algae, oomycetes and animals. Recently, two AA15s from the firebrat Thermobia domestica were reported to have oxidative activity, one towards cellulose or chitin and the other towards chitin, signalling that AA15 LPMOs from insects potentially have different biochemical functions. Herein, we report the identification and characterization of two family AA15 members from the lower termite Coptotermes gestroi. Addition of Cu(II) to CgAA15a or CgAA15b had a thermostabilizing effect on both. Using ascorbate and O2 as co-substrates, CgAA15a and CgAA15b were able to oxidize chitin, but showed no activity on celluloses, xylan, xyloglucan and starch. Structural models indicate that the LPMOs from C. gestroi (CgAA15a/CgAA15b) have a similar fold but exhibit key differences in the catalytic site residues when compared to the cellulose/chitin-active LPMO from T. domestica (TdAA15a), especially the presence of a non-coordinating phenylalanine nearby the Cu ion in CgAA15a/b, which appears as a tyrosine in the active site of TdAA15a. Despite the overall similarity in protein folds, however, mutation of the active site phenylalanine in CgAA15a to a tyrosine did not expanded the enzymatic specificity from chitin to cellulose. Our data show that CgAA15a/b enzymes are likely not involved in lignocellulose digestion but might play a role in termite developmental processes as well as on chitin and nitrogen metabolisms.

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Larger species tend to feed on abundant resources, which nonetheless have lower quality or degradability, the so-called Jarman-Bell principle. The "eat more" hypothesis posits that larger animals compensate for lower quality diets through higher consumption rates. If so, evolutionary shifts in metabolic scaling should affect the scope for this compensation, but whether this has happened is unknown. Here, we investigated this issue using termites, major tropical detritivores that feed along a humification gradient ranging from dead plant tissue to mineral soil. Metabolic scaling is shallower in termites with pounding mandibles adapted to soil-like substrates than in termites with grinding mandibles adapted to fibrous plant tissue. Accordingly, we predicted that only larger species of the former group should have more humified, lower quality diets, given their higher scope to compensate for such a diet. Using literature data on 65 termite species, we show that diet humification does increase with body size in termites with pounding mandibles, but is weakly related to size in termites with grinding mandibles. Our findings suggest that evolution of metabolic scaling may shape the strength of the Jarman-Bell principle.

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Planicapritermes Emerson, 1949 is a South American termite genus with two nominal species: Planicapritermes planiceps (Emerson, 1925) and Planicapritermes longilabrum Constantino, 1998. The soldiers of this genus are characterized by strongly asymmetrical mandibles. Planicapritermes planiceps was described from soldiers and workers, and P. longilabrum only from soldiers. Here we describe and illustrate workers of P. longilabrum based on specimens collected in Rondônia state, Brazil. We also present a comparison between workers and soldiers of P. planiceps and P. longilabrum, and describe the nest of P. planiceps.(AU)

Planicapritermes Emerson, 1949 é um gênero de cupins da América do Sul com duas espécies nominais: Planicapritermes planiceps (Emerson, 1925) e Planicapritermes longilabrum Constantino, 1998. Os soldados deste gênero são caracterizados por ter mandíbulas fortemente assimétricas. Planicapritermes planiceps foi descrita com base em soldados e operários, e P. longilabrum somente em soldados. Aqui nós descrevemos e ilustramos os operários de P. longilabrum com base em espécimes coletados em Rondônia, Brasil. Também comparamos operários e soldados de P. planiceps e P. longilabrum, e descrevemos o ninho de P. planiceps.(AU)

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Protease inhibitors are involved in the regulation of endogenous cysteine proteases during seed development and play a defensive role because of their ability to inhibit exogenous proteases such as those present in the digestive tracts of insects. Araucaria angustifolia seeds, which can be used in human and animal feed, were investigated for their potential for the development of agricultural biotechnology and in the field of human health. In the pine nuts extract, which blocked the activities of cysteine proteases, it was detected potent insecticidal activity against termites (Nasutitermes corniger) belonging to the most abundant termite genus in tropical regions. The cysteine inhibitor (AaCI-2S) was purified by ion-exchange, size exclusion, and reversed-phase chromatography. Its functional and structural stability was confirmed by spectroscopic and circular dichroism studies, and by detection of inhibitory activity at different temperatures and pH values. Besides having activity on cysteine proteases from C. maculatus digestive tract, AaCI-2S inhibited papain, bromelain, ficin, and cathepsin L and impaired cell proliferation in gastric and prostate cancer cell lines. These properties qualify A. angustifolia seeds as a protein source with value properties of natural insecticide and to contain a protease inhibitor with the potential to be a bioactive molecule on different cancer cells.

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Here, we characterize two novel GH5 endoglucanases (GH5CelA and GH5CelB) from an uncultured bacterium identified in termite gut microbiomes. Both genes were codon-optimized, synthetized, cloned, and expressed as recombinant proteins in Escherichia coli for subsequent purification. Both enzymes showed activity on the pNPC and barley ß-glucan substrates, whereas GH5CelB also showed low activity on carboxymethyl cellulose. The optimum conditions for both enzymes were an acid pH (5) and moderate temperature (35 to 50 °C). The enzymes differed in the kinetic profiles and patterns of the generated hydrolysis products. A structural-based modeling analysis indicated that both enzymes possess a typical (ß/α)8-barrel fold characteristic of GH5 family, with some differential features in the active site cleft. Also, GH5CelB presents a putative secondary binding site. Furthermore, adjacent to the active site of GH5CelA and GH5CelB, a whole subdomain rarely found in GH5 family may participate in substrate binding and thermal stability.Therefore, GH5CelA may be a good candidate for the production of cello-oligosaccharides of different degrees of polymerization applicable for feed and food industries, including prebiotics. On the other hand, GH5CelB could be useful in an enzymatic cocktail for the production of lignocellulosic bioethanol, because of the production of glucose as a hydrolysis product. Key Points • Synthetic metagenomics is a powerful approach for discovering novel enzymes. • Two novel GH5 endoglucanases from nonculturable microorganisms were characterized. • Structural differences between them and other GH5 endoglucanases were observed. • The enzymes may be good candidates for feed, food, and/or bioethanol industries.

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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.

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Acorhinotermes Emerson, 1949 is the only Neotropical Rhinotermitine genus with no major soldier. Herein Acorhinotermes claritae Castro & Scheffrahn, sp. nov. is described based on minor soldiers and an alate nymph collected in a secondary rain forest in the Colombian Amazon. The minor soldier of A. claritae Castro & Scheffrahn, sp. nov. has longer mandibular points and it is comparatively smaller than A. subfusciceps. An illustrated key to the minor soldiers of the Neotropical species of Rhinotermitinae is presented.

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Mercury pollution is currently a major public health concern, given the adverse effects of mercury on wildlife and humans. Soil plays an essential role in speciation of mercury and its global cycling, while being a habitat for a wide range of terrestrial fauna. Soil fauna, primarily soil-feeding taxa that are in intimate contact with soil pollutants are key contributors in the cycling of soil mercury and might provide relevant indications about soil pollution. We studied the enrichment of various mercury species in the nests and bodies of soil-feeding termites Silvestritermes spp. in French Guiana. Soil-feeding termites are the only social insects using soil as both shelter and food and are major decomposers of organic matter in neotropical forests. Nests of S. minutus were depleted in total and mobile mercury compared to nearby soil. In contrast, they were enriched 17 times in methylmercury. The highest concentrations of methylmercury were found in body of both studied termite species, with mean bioconcentration factors of 58 for S. minutus and 179 for S. holmgreni relative to the soil. The assessment of the body distribution of methylmercury in S. minutus showed concentrations of 221 ng g-1 for the guts and even higher for the gut-free carcasses (683 ng g-1), suggesting that methylmercury is not confined to the gut where it was likely produced, but rather stored in various tissues. This enrichment in the most toxic form of Hg in termites may be of concern on termite predators and the higher levels in the food chain that may be endangered through prey-to-predator transfers and bioaccumulation. Soil-feeding termites appear to be promising candidates as bio-indicators of mercury pollution in soils of neotropical rainforest ecosystems.

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The mechanisms that structure species communities are still debated. We addressed this question for termite assemblages from tropical dry forests in Colombia. These forests are endangered and poorly understood ecosystems and termites are important ecosystem engineers in the tropics. Using biodiversity and environmental data, combined with phylogenetic community analyses, trait mapping, and stable isotopes studies, we investigated the termite community composition of three protected dry forests in Colombia. Our data suggest that the structuring mechanisms differed between sites. Phylogenetic overdispersion of termite assemblages correlated with decreasing rainfall and elevation and increasing temperature. Food niche traits-classified as feeding groups and quantified by δ15N‰ and δ13C‰ isotope signatures-were phylogenetically conserved. Hence, the overdispersion pattern implies increasing interspecific competition with decreasing drier and warmer conditions, which is also supported by fewer species occurring at the driest site. Our results are in line with a hypothesis that decreased biomass production limits resource availability for termites, which leads to competition. Along with this comes a diet shift: termites from drier plots had higher δ13C signatures, reflecting higher δ13C values in the litter and more C4 plants. Our study shows how a phylogenetic community approach combined with trait analyses can contribute to gaining the first insights into mechanisms structuring whole termite assemblages.

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Two recombinant protease inhibitors from Bauhinia bauhinioides, rBbKI (kallikrein inhibitor) and rBbCI (cruzipain inhibitor) were evaluated for insecticidal activity against workers and soldiers of Nasutitermes corniger (order: Isoptera; family: Termitidae) through the inhibitors' effect on the insect's gut enzymes. The inhibitor rBbKI was more effective than rBbCI in inhibiting the termite's gut enzymes. The kallikrein inhibitor showed termiticidal activity in workers with an LC50 of 0.9 mg mL-1 after 4 days. Conversely, rBbKI did not affect the survival of soldiers and rBbCI did not show termiticidal activity against N. corniger. The two inhibitors showed different specificity towards the termite's gut enzymes, representing interesting tools to characterize N. corniger enzymes. The different effects of rBbKI and rBbCI on the termite's enzymes and survival may be linked to slight structural differences between these inhibitors.

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