Identification of trail pheromone compounds from the labial glands of the stingless bee Geotrigona mombuca

Foragers of several species of stingless bees deposit pheromone spots in the vegetation to guide recruited nestmates to a rich food source. Recent studies have shown that Trigona and Scaptotrigona workers secrete these pheromones from their labial glands. An earlier report stated that species within the genus Geotrigona use citral from their mandibular glands for scent marking. Since convincing experimental proof for this conjecture is lacking, we studied the glandular origin of the trail pheromone of Geotrigona mombuca. In field bioassays, newly recruited bees were diverted by artificial scent trails that branched off from the natural scent trail deposited by their nestmates only when they were baited with extracts from the foragers` labial glands. Compounds extracted from the mandibular glands, however, did not release trail following behavior. This demonstrates that the trail pheromone of G. mombuca is produced in the labial glands, as in Trigona and Scaptotrigona. Furthermore, in chemical analyses citral was identified exclusively in the foragers` mandibular glands, which disproves its supposed role as a trail pheromone. The labial glands contained a series of terpene- and wax type esters, with farnesyl butanoate as major constituent. We, therefore, postulate that the trail pheromone of G. mombuca is composed of a blend of esters.

Unusual labial glands in snakes of the genus Geophis Wagler, 1830 ( Serpentes: Dipsadinae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ablation of caterpillar labial salivary glands: technique for determining the role of saliva in insect-plant interactions.

There has been an ardent interest in herbivore saliva due to its roles in inducing plant defenses and its impact on herbivore fitness. Two techniques are described that inhibit the secretion of labial saliva from the caterpillar, Helicoverpa zea, during feeding. The methods rely on cauterizing the caterpillar's spinneret, the principal secretory structure of the labial glands, or surgically removing the labial salivary gland. Both methods successfully inhibit secretion of saliva and the principal salivary enzyme glucose oxidase. Caterpillars with inhibited saliva production feed at similar rates as the untreated caterpillars, pupate, and emerge as adults. Glucose oxidase has been suggested to increase the caterpillar's survival through the suppression of inducible anti-herbivore defenses in plants. Tobacco (Nicotiana tabacum) leaves fed on by caterpillars with ablated salivary glands had significantly higher levels of nicotine, an inducible anti-herbivore defense compound of tobacco, than leaves fed upon by caterpillars with intact labial salivary glands. Tomato (Lycopersicon esculentum) leaves fed upon by caterpillars with suppressed salivary secretions showed greatly reduced evidence of hydrogen peroxide formation compared to leaves fed upon by intact caterpillars. These two methods are useful techniques for determining the role that saliva plays in manipulating plant anti-herbivore defenses.

Influence of the labial gland's semiochemicals on the feeding behavior of Coptotermes havilandi (Isoptera: Rhinotermitidae)

In termites, food search is mediated by semiochemicals that are liberated by exocrine glands. In the present work we investigated the effect of the secretion of the labial glands of workers on the feeding behavior of Coptotermes havilandi. The secretion of the labial glands exhibited phagostimulant effect on the workers of this species. The soldiers showed a low activity in response to the labial gland extracts suggesting that this gland's secretion might inhibit the recruitment of soldiers. Behavioral evidence for the regulation of food consumption by workers was observed.

Changes in chemical profile of cephalic salivary glands of Scaptotrigona postica (Hymenoptera, Meliponini) workers are phase-related

Most advanced eusocial bees recruit their nestmates to food resources. Recently, studies in Meliponini species showed that the cephalic salivary (labial) glands (CSGs) are responsible for the production of scent-trail pheromones. Studies on CSGs have shown changes in glandular cell morphology since the worker emerges from brood combs (newly emerged) till forager phase, which may be correlated to changes in the composition of secretion produced. However, no study has been made till now regarding to the composition of CSGs secretion of Scaptotrigona postica and the chemical changes that occur in this secretion according to the worker's life phase or tasks performed. In this study, the chemical profile of CSG secretion in S. postica workers was studied. Glands were taken from specimens newly emerged (NE), working in the brood combs area (CA) and forager (FO) and were analyzed by gas chromatography-mass spectrometry. The results showed that glandular secretion consists of oxygenated compounds of middle volatility (acids, alcohols, aldehydes, ketones, esters and ether), and their quantity varies among the different phases of life, increasing as the individual undergoes from intra- to extra-colonial activities. The NE phase contained the smallest variety and quantity of compounds. Due to the variability of compounds, the CA workers were separated into 3 groups according to the chemical constitution of their secretion. Forager workers showed the largest quantity and variety of chemical compounds. The major compounds in forager gland secretion are 7-hexadecen-1-yl acetate and 5-tetradecen-1-yl acetate. Statistical analysis indicates that the chemical composition of glandular secretion is task-related.

Olfactory eavesdropping between two competing stingless bee species

Foragers can improve search efficiency, and ultimately fitness, by using social information: cues and signals produced by other animals that indicate food location or quality. Social information use has been well studied in predator-prey systems, but its functioning within a trophic level remains poorly understood. Eavesdropping, use of signals by unintended recipients, is of particular interest because eavesdroppers may exert selective pressure on signaling systems. We provide the most complete study to date of eavesdropping between two competing social insect species by determining the glandular source and composition of a recruitment pheromone, and by examining reciprocal heterospecific responses to this signal. We tested eavesdropping between Trigona hyalinata and Trigona spinipes, two stingless bee species that compete for floral resources, exhibit a clear dominance hierarchy and recruit nestmates to high-quality food sources via pheromone trails. Gas chromatography-mass spectrometry of T. hyalinata recruitment pheromone revealed six carboxylic esters, the most common of which is octyl octanoate, the major component of T. spinipes recruitment pheromone. We demonstrate heterospecific detection of recruitment pheromones, which can influence heterospecific and conspecific scout orientation. Unexpectedly, the dominant T. hyalinata avoided T. spinipes pheromone in preference tests, while the subordinate T. spinipes showed neither attraction to nor avoidance of T. hyalinata pheromone. We suggest that stingless bees may seek to avoid conflict through their eavesdropping behavior, incorporating expected costs associated with a choice into the decision-making process.

Especializações glandulares, musculares e dentárias dos dipsadíneos goo-eaters (Serpentes: Dipsadinae) associadas à ingestão de suas presas

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

SCANNING ELECTRON-MICROSCOPY OF THE RHODNIUS-NEGLECTUS (HEMIPTERA) LABIAL SALIVARY-GLANDS AFTER STARVATION

Labial salivary glands are found in the majority of insects. They are relatively large, extend back into the thorax, and in Rhodnius, they are cherry red in color due to a pigment derived from traces of hemoglobin absorbed form the gut. In most insects they are acinous shaped, with long excretion channels that present differentiated regions which from salivary reservoirs. The glands may be relatively simple or complexly branched and convoluted. In Rhodnius they are described as being unilobed with no traces of division. The main duct leaves the gland at its anterior extremity. The acini have different kinds of cells but all of them are seen as sources of secretion. Our material has a different shape due to the fact that the animals spent 20 days under starvation conditions. New data are also obtained through treatment with collagenase and HCl. The importance of the study of these glands lies in the fact that it will further understanding of the transmission of Chagas' disease.

Changes in the size of cephalic salivary glands of Apis mellifera and Scaptotrigona postica (Hymenoptera: Apidae) queens and workers in different life phases

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cephalic salivary glands of two species of advanced eusocial bees (Hymenoptera: Apidae): morphology and secretion

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

PHEROMONES and EXOCRINE GLANDS IN ISOPTERA

Termites are eusocial insects that have a peculiar and intriguing system of communication using pheromones. The termite pheromones are composed of a blend of chemical substances and they coordinate different social interactions or activities, including foraging, building, mating, defense, and nestmate recognition. Some of these sociochemicals are volatile, spreading in the air, and others are contact pheromones, which are transmitted by trophallaxis and grooming. Among the termite semiochemicals, the most known are alarm, trail, sex pheromones, and hydrocarbons responsible for the recognition of nestmates. The sources of the pheromones are exocrine glands located all over the termite body. The principal exocrine structures considered pheromone-producing glands in Isoptera are the frontal, mandibular, salivary or labial, sternal, and tergal glands. The frontal gland is the source of alarm pheromone and defensive chemicals, but the mandibular secretions have been little studied and their function is not well established in Isoptera. The secretion of salivary glands involves numerous chemical compounds, some of them without pheromonal function. The worker saliva contains a phagostimulating pheromone and probably a building pheromone, while the salivary reservoir of some soldiers contains defensive chemicals. The sternal gland is the only source of trail-following pheromone, whereas sex pheromones are secreted by two glandular sources, the sternal and tergal glands. To date, the termite semiochemicals have indicated that few molecules are involved in their chemical communication, that is, the same compound may be secreted by different glands, different castes and species, and for different functions, depending on the concentration. In addition to the pheromonal parsimony, recent studies also indicate the occurrence of a synergic effect among the compounds involved in the chemical communication of Isoptera. (C) 2010 Elsevier B.V.

Morphological changes in the cephalic salivary glands of females and males of Apis mellifera and Scaptotrigona postica (Hymenoptera, Apidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphology of the male agouti accessory genital glands (Dasyprocta prymnolopha Wagler, 1831)

The morphology of the accessory genital glands of the male agouti was studied in twenty-three animals that were raised in captivity. Twenty animals had their genital glands dissected in situ for macroscopic description. The samples of each gland were recovered, embedded in paraffin, sliced and stained by Hematoxylin-Eosin technique. It was founded four pairs of glands: the vesicular glands, the coagulating glands, the prostate and the bulbourethral glands. Histological characteristics of the vesicular, coagulating and prostate glands showed similar morphology, within the pseudostratified columnar epithelium. The tubulo-alveolar type of the bulbourethral glands showed a lack of connective tissue among the tubules, a small amount of red stained presented it the cytoplasm, and the presence of vacuoles in the tissue. This study concluded that the agouti showed to have similar morphological aspect described in the others species of rodents.

Isolation of rabies virus from the parotid salivary glands of foxes (Pseudalopex vetulus) from Paraíba State, Northeastern Brazil

To determine the presence of rabies virus in the parotid salivary glands, 12 road-killed rabies-positive hoary foxes (Pseudoalopex vetulus) were tested by using the fluorescent antibody test (FAT) and mouse inoculation test (MIT). All 12 parotid salivary glands were positive for both tests, although in some cases several passages were required. The findings of this study support the importance of the hoary fox as rabies reservoir in the semi-arid region of Paraíba State, Northeastern Brazil.

Contact endoscopy for identifying the parathyroid glands during thyroidectomy

Aim of this study was to analyse contact endoscopy as an auxiliary method for identifying parathyroid glands during thyroid surgery and to identify other variables that may interfere with this correlation. overall, 125 patients underwent thyroid surgery between January 2004 and February 2006. The variables analysed were: the total duration of surgery; time taken to locate and identify parathyroid glands; improvement in identifying these; numbers of parathyroid glands located by the surgeon and confirmed by contact endoscopy; histopathological diagnosis; presence of thyroiditis; thyroid weight; number of parathyroid glands left in thyroid specimens; and number of parathyroid gland autotransplantations. A total of 331 parathyroid glands were observed by the surgeon. however, 282 glands were identified by contact endoscopy. nine parathyroid glands (7.2%) were observed together with thyroid specimens (Kappa = 0.534). The longer the total duration of surgery (p = 0.03) and time taken to locate and identify (p = 0.00) the parathyroid glands by contact endoscopy, the lower the observed agreement. The second year of performing contact endoscopy led to better agreement between the results (p = 0.02). in conclusion, contact endoscopy is an efficient auxiliary method for identifying parathyroid glands during thyroid surgery. During the period studied, association between total duration of surgery and time taken to locate and identify parathyroid glands was statistically significant.