Mating- and oviposition-dependent changes of the spermatheca and colleterial glands in the pest termite Cryptotermes brevis (Blattaria, Isoptera, Kalotermitidae).

The spermatheca and colleterial glands of female insects are organs associated with the reproductive system, responsible for sperm storage and secretion of egg coverings, respectively. Here we compared the development, secretory activity, and chemical nature of the secretion in the spermatheca and colleterial glands of different-aged females of the drywood termite Cryptotermes brevis. We also provide the ultrastructure of these organs in alate females. These structures have been poorly investigated in termites when compared to other eusocial insects (Hymenoptera) and termite-related dictyopterans (mantises and cockroaches). The spermatheca of C. brevis comprises a cone-shaped structure, connected to the genital chamber by a short duct. The colleterial glands, in turn, are divided into anterior and posterior tubules, each showing a basal trunk, and join into a common duct. Histological and histochemical analyses showed that the secretion of proteins and polysaccharides by the spermatheca takes place before pairing, but increases as females mate and store sperm. Colleterial glands of alates showed non-synchronous secretory activity, but the synthesis of products increased in egg-laying queens, together with the epithelium height. Ultrastructure of the spermatheca and colleterial glands revealed epithelia composed of class III secretory cells. Richness of mitochondria and electron-dense secretion in the spermatheca indicates synthesis and transport of content. Presence and absence of colleterial gland secretion in different individuals may reflect variable maturation stages of the females and secretory cells. Assuming that termites are iteroparous, the development and secretion of the spermatheca and colleterial glands play a crucial role for C. brevis queens.

Secretory oviducts contribute to the high egg-laying rate of physogastric termite queens (Isoptera: Termitidae).

Physogastric termite queens are characterized by a notorious enlargement of the abdomen triggered by an equal development of the ovaries. Other physogastry-related modifications have been reported on the fat body, cuticle, midgut, tracheal system, and hemolymph. Surprisingly, modifications on the lateral oviducts of these females, important sites for ovulation and egg transport, have received little attention. Here we took advantage of the high fecundity of physogastric queens in three termitid species to evaluate ovary development and also to compare the morphophysiological features of the lateral oviducts between early-mated and physogastric queens of Cornitermes cumulans. Older queens show well-developed ovaries, with numerous ovarioles connected to the lateral oviducts through pedicels. At these sites, several corpora lutea were observed, residual follicle cells from previous ovulation events. Such features were absent among early-mated queens and reflect then the maturity and ageing of the queens. Histological and histochemical analyses indicated that secretory activity of the lateral oviducts was also restricted to physogastric queens, in which proteins, but not polysaccharides, are secreted into the oviduct lumen. The likely function of these proteins, based on previous studies, is to lubricate the lateral oviducts and stimulate muscular contractions to the egg transport. The physogastry of termite queens is a notorious feature, characterized by several body modifications, especially concerning the ovaries. Our results shed light on the physogastry-related changes in the lateral oviducts of termite queens, as their increasing secretory activity is in agreement with the high number of eggs produced and transporting through these structures. Thus, such changes correspond to an important step allowing the high egg-laying rate shown by physogastric termite queens.

Differentiation of workers into soldiers is associated with a size reduction of higher-order brain centers in the neotropical termite Procornitermes araujoi.

Comparing the size of functionally distinct brain regions across individuals with remarkable differences in sensory processing and cognitive demands provides important insights into the selective forces shaping animal nervous systems. We took advantage of the complex system of worker-to-soldier differentiation in the termitid Procornitermes araujoi, to investigate how a profound modification of body morphology followed by an irreversible shift in task performance are translated in terms of brain structure and size. This behavioural shift is characterised by a reduction of the once wide and complex behavioural repertoire of workers to one exclusively dedicated to nest defence (soldiers). In accordance with soldier's reduced cognitive and sensory demands, we show here that differentiation of workers into soldiers is associated with a size reduction of the mushroom body (MB) compartments, higher-order brain regions responsible for multimodal processing and integration of sensory information, as well as learning, memory, and decision-making. Moreover, in soldiers, we found an apparent fusion of the medial and lateral MB calyces likely associated with its volume reduction. These results illustrate a functional neuroplasticity of the MB associated with division of labour, supporting the link between MB size and behavioural flexibility in social insect workers.

Functional Morphology and Development of the Colleterial Glands in Non- and Egg-Laying Females of the Pest Termite Coptotermes gestroi (Blattaria, Isoptera, Rhinotermitidae).

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.

On the reproductive strategies post-colony foundation: major termite pest species with distinct ecological habits differ in their oviposition dynamics.

Termite colony foundation precedes the incipient stage, when the first oviposition cycle takes place, followed by months of reproductive inactivity. The royal couple is supposed to cease oviposition during this period, investing energy to care for the first brood. When a suitable number of alloparents differentiate, egg-laying resumes. Here we followed oviposition dynamics, embryo development and queen/king body changes in laboratory colonies of the major pest species Coptotermes gestroi (Rhinotermitidae) and Cryptotermes brevis (Kalotermitidae) during 9 months. We show that they differ in these oviposition dynamics, as C. gestroi queens displayed an uninterrupted oviposition whereas C. brevis laid a cohort of eggs and ceased oviposition during a 3-month period (lag phase). C. gestroi oviposition dynamic was remarkable and suggests that occurrence of progeny was not a limiting factor, thus queens and kings were able to concomitantly invest energy in reproduction and parental care. These findings contrast those reported for rhinotermitids from temperate areas, and we discuss the likely reasons for such a condition, including endogenous rhythms, avoidance of a high mortality rate of the first progeny and adaptation to the weather conditions of the Neotropical region. Oviposition dynamic in C. brevis resembled those of several termite species, in which the royal couple cease reproduction to care for the first brood. Rearing conditions did not influence oviposition dynamics (egg-laying cycle followed by a lag phase), thus our results on the oviposition of C. gestroi and C. brevis correspond to different reproductive strategies post-foundation adopted by these pest species.

Post-embryonic development of the female reproductive system of the Neotropical termite Silvestritermes euamignathus (Isoptera: Termitidae: Syntermitinae).

In termites, the maturation of the female reproductive system is progressive following post-embryonic development. In Silvestritermes euamignathus, the imaginal line is characterized by five nymphal instars that develop into the imago, but it can deviate in some instars to neotenic reproductives. In order to understand the rate of development of the female reproductive system throughout post-embryonic development, we analyzed the morphology of the reproductive system of nymphs, characterizing the stage of development and comparing it with neotenics and primary queens. We also followed embryonic development and compared eggs from neotenics and primary queens from incipient and mature colonies. Our results showed that gonadal development follows the post-embryonic instars, and previtellogenic oocytes are present in third-instar nymphs and are retained for the next two successive nymphal instars. The full maturation of the ovaries with vitellogenic oocytes requires molting to either imagos or neotenics. Eggs from neotenics follow the same embryonic development and each stage presents similar volume when compared to those of mature primary queens. Eggs of primary queens from incipient colonies are greater in volume than those of mature primary queens and of neotenics, suggesting an investment in egg quality rather than quantity during colony foundation.

First Neotropical record of the association between brown sclerotium-forming fungi and termite eggs in a nest of Coptotermes gestroi (Blattaria, Isoptera, Rhinotermitidae).

Insects and fungi are abundant in many environments, in which facultative and/or obligate associations involving these groups have been established during evolution. In termites, mutualism with fungi is well reported for some termite lineages (e.g., Macrotermitinae). Within some subterranean termite species (Rhinotermitidae), egg-mimicking fungi, also referred to as "termite "balls", are often harbored inside the nest, mixed to the egg piles. Such interaction seems to be advantageous for both partners since the fungi are protected inside the nest while they may serve as an additional food source and also provide cellulases which may be incorporated into the termite digestive process. Although such mutualism has been reported for seven species of Reticulitermes and Coptotermes formosanus, all the samplings were restricted to temperate regions. Here, we provide the first Neotropical record of this termite-fungus association, and the first report for Coptotermes gestroi. The morphological characters of the "termite balls" observed in a C. gestroi nest resemble those already reported for Reticulitermes spp. and the congeneric species C. formosanus. They include a color ranging from light to dark brown, spherical shape, and a reduced diameter (0.23-0.34 mm). Our findings provide new insights into the geographical distribution of the association between termites and sclerotium-forming fungi. Future genetic analyses will be valuable aiming to identify the egg-mimicking fungi associated with C. gestroi and shed light on the evolution of this fascinating symbiosis.

Comparative reproductive biology of pre-, imaginal, and neotenic castes of the Asian termite Coptotermes gestroi (Blattaria, Isoptera, Rhinotermitidae).

The Asian subterranean termite Coptotermes gestroi is a worldwide structural pest, although its reproductive biology has been poorly investigated due to a cryptic habit and occurrence of polycalic nests. In this study, we investigated ovarian development and oogenesis in different-aged females of C. gestroi: fourth-instar nymphs, non-functional neotenics, alates, and functional queens. We show that the ovaries develop gradually according to their age and functionality, as younger individuals possess immature oocytes, whereas alates and functional queens always undergo vitellogenesis. Oocytes were classified into previtellogenic (stages I, II, and III) or vitellogenic (stages IV, V, and VI). Ovary development varied among non-functional neotenics, and a rapid differentiation and/or the presence of primary reproductives are believed to influence such a maturation. Immature oocyte stages were shared between fourth-instar nymphs and neotenics. These characteristics, together with other neotenic features (wing buds, body pigmentation, and eye color), should be evaluated in detail aiming to clarify which nymphal instars differentiate into secondary reproductives. Oogenesis was not uniform among alate females, and cross-sectional area of terminal oocytes was significantly smaller in alates when compared to functional queens, suggesting different degrees of maturation in swarming individuals. Functional queens always had mature terminal oocytes (stage VI). Ovariole number and oocyte maturation in C. gestroi relies on several factors and may therefore differ among individuals of the same caste. Future studies should take into account these reproductive features to evaluate how they impact colony development.

Salivary glands in workers of Ruptitermes spp. (Blattaria, Isoptera, Termitidae, Apicotermitinae): a morphological and preoteomic approach.

Salivary glands are omnipresent in termites and occur in all developmental stages and castes. They function to produce, store, and secrete compounds, ranging from a feeding function to defensive mechanisms. Here, we provide a complete morphological overview of the salivary glands in the soldierless species Ruptitermes reconditus and R. xanthochiton, and the first proteomic profile of the salivary glands in a Neotropical Apicotermitinae representative, R. reconditus. Salivary glands from both species were composed of several acini, roughly spherical structures composed of two types of central cells (type I and II) and peripheral parietal cells, as well as transporting ducts and two salivary reservoirs. Central cells were richly supplied with electron-lucent secretory vesicles and rough endoplasmic reticulum, a feature of protein-secreting cells. Parietal cells of Ruptitermes spp. had conspicuous characteristics such as electron-lucent secretory vesicles surrounded by mitochondria and well-developed microvilli. Moreover, different individuals showed variation in the secretory cycle of salivary acini, which may be related to polyethism. Ultrastructural analysis evidenced a high synthesis of secretion and also the occurrence of lysosomes and autophagic structures in central cells. Proteomic analysis of the salivary glands revealed 483 proteins divided into functional groups, highlighting toxins/defensins and compounds related to alarm communication and colony asepsis. Soldierless termites are quite successful, especially due to morphological adaptations of the workers, including unknown modifications of exocrine glands. Thus, according to our morphological and proteomic findings, we discuss the potential roles of the salivary gland secretion in different social aspects of the sampled species.

Involvement of the Salivary Glands in the Suicidal Defensive Behavior of Workers in Neocapritermes opacus (Blattaria, Isoptera, Termitidae).

Suicidal behavior in termite workers is an extreme defensive strategy, probably a consequence of having a low number of soldiers available in the colony and there being high predation from enemies. We investigated the suicidal mechanism in workers of the Neotropical termite Neocapritermes opacus, which involves salivary gland autothysis followed by body cuticle rupture and the release of a defensive secretion. Autothysis was triggered by a physical stimulus such as a soldier bite that causes the protrusion of the salivary acini, burst reservoirs, and foregut. Histochemical and ultrastructural analyses showed salivary acini composed of peripheral parietal cells and two types of central cells, types I and II. Type I cells are filled with large electron-lucent secretory vesicles, which reacted positively to bromophenol blue and xylidine-Ponceau tests, indicating the occurrence of proteins. Type II cells are elongated and display smaller apical secretory vesicles. Parietal cells present an intracellular canaliculus with dense microvilli and cytoplasm rich in mitochondria and large electron-dense vesicles, which may participate in the self-destructive mechanism. Worker suicidal behavior was previously reported for N. taracua and N. braziliensis. N. opacus is a new species in which a salivary weapon has been developed and factors contributing to this altruistic response are discussed.

Ergatoid reproductives in the Neotropical termite Nasutitermes aquilinus (Holmgren) (Blattaria: Isoptera: Termitidae): developmental origin, fecundity, and genetics.

Termite colonies are usually headed by primary reproductives, which establish nests during the swarming season. However, secondary reproductives may develop in some species and become supplementary or replacement breeders, extending colony lifespan. Here we investigate the developmental origin, fecundity and genetic characterization of ergatoid reproductives in the Neotropical termite Nasutitermes aquilinus (Holmgren), using morphometrical and histological techniques, five microsatellite loci and the COI mitochondrial DNA. Twelve measurements performed on 208 apterous individuals of N. aquilinus revealed 10 groups, including ergatoid females, which developed from major workers through two successive molts, and were characterized by the presence of imaginal features such as eyes and wing buds. The differentiation of these features was correlated to physogastric development in these ergatoids. Histology revealed oocytes in all maturation stages in worker-derived reproductives of N. aquilinus, presence of nonflagellate spermatozoa inside the spermatheca, and royal fat body. Thus, ergatoid reproductives were reproductively functional. According to the genotypes of 221 individuals from 11 nests, and mitochondrial haplotypes of 43 ergatoids, 73% of the colonies were simple families, whereas 27% were extended families. Despite the occurrence of related reproductives, low inbreeding rates were detected within and among colonies. Such values could be explained given that sib mating itself cannot result in a higher inbreeding rate but depend on several factors discussed in detail. This is the first study to investigate the genetic structure of termite colonies influenced by the development of ergatoids, and further investigations are encouraged to understand the influence of these reproductives on colony lifespan.

Development and comparative morphology of the reproductive system in different aged males of the drywood termite Cryptotermes brevis (Blattaria, Isoptera, Kalotermitidae).

Termites are eusocial cockroaches, which have received great attention due to their diversity of reproductive strategies. Although these novelties allow new interpretations concerning the mating biology of these insects, studies highlighting the structure of the reproductive system are limited to some termite lineages. Here we provide the first comparative analysis of the reproductive system of a drywood termite, using different aged males of Cryptotermes brevis as models. This species represents an important structural pest in tropical regions, and most aspects of its reproductive biology remain unknown, especially on males. The reproductive apparatus of C. brevis is equipped with paired testes, composed of seven testicular lobes, in which developing spermatozoa are located. The basal portion of the lobes connects to the vasa deferentia and transport spermatozoa to a pair of enlarged chambers, the seminal vesicles. These structures join in a median ejaculatory duct, which opens to the external region through a retractile penis. Spermatozoa were observed in all C. brevis males, exhibiting elongated morphology and measuring about 10 µm in length/4 µm in width. Compared with last-instar nymphs and alates, functional kings showed enlarged testes and seminal vesicles, as well as an intense secretory activity towards the lumen of the latter structures. Histochemical tests evidenced strongly PAS and xylidine Ponceau positive reactions of the secretion only in functional kings, indicating the occurrence of glycoproteins. Thus, we suggest that morphophysiological changes establish during the maturation of the reproductive system in C. brevis.

Proteomic-components provide insights into the defensive secretion in termite workers of the soldierless genus Ruptitermes.

Termite soldiers constitute the defensive frontline of the colonies, despite workers also perform such tasks, especially within the Neotropical Apicotermitinae, in which all species are soldierless. Workers of the genus Ruptitermes display an extreme form of defense, characterized by body rupture and release of a sticky secretion. Previous observations suggested that such behavior may be advantageous against enemies, but the chemical composition of this secretion has been neglected. Here we firstly provide the proteomic profile of the defensive secretion of Ruptitermes reconditus and Ruptitermes pitan workers. Additionally, the mechanisms of action of this behavior was evaluated through different bioassays. A total of 446 proteins were identified in R. reconditus and 391 proteins in R. pitan, which were classified into: toxins, defensins and proteolytic enzymes; sticky components/ alarm communication; proteins related to detoxification processes; proteins involved in folding/conformation and post-translational modifications; housekeeping proteins; and uncharacterized/hypothetical proteins. According to the bioassays, the self-sacrifice is triggered by a physical stimulus, and the defensive secretion may cause immobility and death of the opponents. Assuming that termites are abundant in the tropics and therefore exposed to predators, suicidal behaviors seem to be advantageous, since the loss of an individual benefit the whole colony. SIGNIFICANCE: Although recent studies have reported the biochemical composition of different weapons in soldiered species of termites, such efforts had not been applied to sordierless taxa up until now. Thus, this is the first report of the defensive mechanisms in soldierless termite species based on proteomic analysis. The diversity of compounds, which included toxin-like and mucin-like proteins, reflect the mechanisms of action of the defensive secretion released by termite workers, which may cause immobility and death of the opponents. Our findings may contribute to the knowledge regarding the development of defensive strategies in termites, especially in groups which lost the soldier caste during the evolution.

A Glycoproteinaceous Secretion in the Seminal Vesicles of the Termite Coptotermes gestroi (Isoptera: Rhinotermitidae).

Coptotermes gestroi is a subterranean termite with colonies generally headed by a pair of primary reproductives, although neotenics may occur. In this study, the male reproductive system was compared during different life stages of nymphs, alates, neotenic reproductives, and kings of C. gestroi, focusing on the modifications of this system along the maturation of these individuals. The structure of the male reproductive system follows the pattern described for insects, although C. gestroi males do not exhibit conspicuous penises and differentiated accessory glands. In kings, each testis consisted of about seven lobes, significantly increased in size as compared to younger males. The spermatogenesis begins in third-instar nymphs, which already presented spermatozoa in the testes. The seminal vesicles are individualized in C. gestroi and have a secretory distal portion and a proximal portion with a role in spermatozoa storage. The secretion of the seminal vesicles is strongly periodic acid Schiff (PAS)-positive, whereas the xylidine Ponceau test revealed proteins that increase in quantity while the males become older. This is the first record of glycoproteins in the lumen of seminal vesicles in termites. Further studies will clarify how they are produced and interact in the physiology and nutrition of the non-flagellate spermatozoa of C. gestroi.

Facing death: How does the subterranean termite Coptotermes gestroi (Isoptera: Rhinotermitidae) deal with corpses?

Social insects display a range of sophisticated behaviors to deal with cadavers, which together act to guarantee the health and social homeostasis of their colonies. In termites, cadaver management involves an entire repertoire of activities, such as antennation, grooming, retreat, alarm and agonistic behaviors. We performed different bioassays to evaluate whether postmortem-age, origin and caste of a cadaver influence the behavior of Coptotermes gestroi. Quantitative analyses of corpse management behaviors indicated that C. gestroi is able to discriminate the origin and caste of cadavers. Cadavers of worker nestmates were preferentially cannibalized while corpses of alien workers were buried. In addition, soldiers that had been dead for 24hours were buried while freshly dead soldiers were either buried, consumed or ignored, indicating a plastic behavioral response that depends on postmortem age. Corpse consumption is an important component of corpse management repertoire because this process eliminates contaminant and enables nutrient recycling. The physical isolation of the termite corpse through burial after grooming also helps to prevent other colony members from contacting the cadaver, further mitigating against the potential spread of disease.

Worker Defensive Behavior Associated with Toxins in the Neotropical Termite Neocapritermes braziliensis (Blattaria, Isoptera, Termitidae, Termitinae).

Termite societies are abundant in the tropics, and are therefore exposed to multiple enemies and predators, especially during foraging activity. Soldiers constitute a specialized defensive caste, although workers also participate in this process, and even display suicidal behavior, which is the case with the species Neocapritermes braziliensis. Here we describe the morphology, mechanisms of action, and proteomics of the salivary weapon in workers of this species, which due to the autothysis of the salivary glands causes their body rupture, in turn releasing a defensive secretion, observed during aggressiveness bioassays. Salivary glands are paired, composed of two translucent reservoirs, ducts and a set of multicellular acini. Histological and ultrastructural techniques showed that acini are composed of two types of central cells, and small parietal cells located in the acinar periphery. Type I central cells were abundant and filled with a large amount of secretion, while type II central cells were scarce and presented smaller secretion. Parietal cells were often paired and devoid of secretion. The gel-free proteomic approach (shotgun) followed by mass spectrometry revealed 235 proteins in the defensive secretion, which were classified into functional groups: (i) toxins and defensins, (ii) folding/conformation and post-translational modifications, (iii) salivary gland detoxification, (iv) housekeeping proteins and (v) uncharacterized and hypothetical proteins. We highlight the occurrence of neurotoxins previously identified in arachnid venoms, which are novelties for termite biology, and contribute to the knowledge regarding the defense strategies developed by termite species from the Neotropical region.

Behavioural repertoire of termites in corpse management: A comparison between one-piece and multiple-pieces nesting termite species.

Corpse disposal is an essential adaptation to social life. This behaviour promotes nest hygiene and prevents the spread of pathogens in the colony of social insects. The current study verified the corpse management in two termite families towards cadavers of different origins. We carried out bioassays with subcolonies of Cryptotermes brevis and colonies of Cornitermes cumulans, in which corpses of termite workers from the same colony, from another colony and from another species were introduced. The results showed that C. brevis consumed the corpses regardless of their origin, but they avoided the chitinous parts of the head. In this species, consumption of dead individuals, besides performing a hygienic function, seems to be a strategy for nitrogen and water acquisition. In the C. cumulans species, interspecific and intercolonial corpses were covered with soil and faeces after being groomed. Nestmate corpses were entombed, transported to the nest or ignored after being submitted to grooming. Our findings indicate that a one-piece nesting termite, as C. brevis, exhibited a simplified corpse management repertoire in relation to that performed by C. cumulans, a multiple-piece nesting species, whose approach was more complex and diverse. Behavioural responses are associated with the nesting of the species.

Food Storage by the Savanna Termite Cornitermes cumulans (Syntermitinae): a Strategy to Improve Hemicellulose Digestibility?

It has been suggested that food storage inside the nest may offer termites with a nutritional provision during low resource availability. Additionally, feces employed as construction material provide an excellent environment for colonization by microorganisms and, together with the storage of plant material inside the nest, could thus provide some advantage to the termites in terms of lignocellulose decomposition. Here, we conducted for the first time a comprehensive study of the microbial communities associated to a termite exhibiting food storage behavior using Illumina sequencing of the 16S and (ITS2) regions of rRNA genes, together with enzymatic assays and data collected in the field. Cornitermes cumulans (Syntermitinae) stored grass litter in nodules made from feces and saliva located in the nest core. The amount of nodules increased with nest size and isolation, and interestingly, the soluble fraction of extracts from nodules showed a higher activity against hemicellulosic substrates compared to termite guts. Actinobacteria and Sordariales dominated microbial communities of food nodules and nest walls, whereas Spirochetes and Pleosporales dominated gut samples of C. cumulans. Within Syntermitinae, however, gut bacterial assemblages were dissimilar. On the other hand, there is a remarkable convergence of the bacterial community structure of Termitidae nests. Our results suggest that the role of nodules could be related to food storage; however, the higher xylanolytic activity in the nodules and their associated microbiota could also provide C. cumulans with an external source of predigested polysaccharides, which might be advantageous in comparison with litter-feeding termites that do not display food storage behavior.

Hypopharynx in termites: Morphological and functional aspects.

The hypopharynx morphology in workers, pseudergates, and soldiers was described in six families of Isoptera using scanning electronic microscopy. This is the first comparative study to detail the hypopharynx among different species of termites, and included 4 one-piece type (OP) and 9 multiple-pieces type termites (MP). The results showed different arrangements of the hypopharynx trichomes, with fewer of these structures in the frontal region of the hypopharynx in pseudergates and soldiers of OP termites. These characteristics did not apply to Serritermes serrifer, since its pseudergates displayed a large quantity of trichomes on the frontal surface. This species may not resemble other OP termites because it does not live inside a piece of wood, but rather are inquilines inside Cornitermes spp. nests. Similar morphology of this mouthpart was observed in the different species of MP termites, with workers exhibiting many unidirectional trichomes on the frontal surface and soldiers presenting fewer of these trichomes. The morphology of the hypopharynx seems to reflect the lifestyle of these species, because MP termites are able to exploit external water sources. Since different arrangements of hypopharynx trichomes are used for water intake via capillary action, the present data reinforce the soldiers' dependence on workers to obtain water and food through the process of trophallaxis. Three different types of sensilla were observed on the lateral region of the hypopharynx: chaetica, basiconica and campaniformia. Chaetica act as chemoreceptors, while basiconica and campaniformia are mechanoreceptors, used in feeding and environmental perception. Better understanding of hypopharynx morphology permits the inference of ecological habits among OP and MP termites, and reflects the physiological differences between workers and soldiers.