ABSTRACT
Nestmate recognition is fundamental for the cohesiveness of the colony in social insects. Acromyrmex landolti is a higher Attini, a leaf-cutter ant with largest nest and morphological castes. We studied the location of the recognition signal of A. landolti on the whole ant body, the isolation effect on the capacity of nestmaterecognition, and the role of the mandibular (MG) and post-pharyngeal glands (PPG) as putative sources for chemical recognition signals in this species. We performed behavioral bioassays and chemical analyses of MG and PPG glands; MG volatiles in different castes were also characterized. In order to determine the occurrence of nestmate recognition signals, behavioral tests were performed for which the whole body, body parts or gland extracts from a nestmate and an alien worker ant, were placed on the central axis of an active field trail. Besides, the isolation effect of the nestmate chemical signal persistence was evaluated by repeating the experiments with whole ant bodies after 12h, 24h and 48h of isolation. The agonistic behavior of the ants on the trail was classified as inspection, threatening and biting. Gland volatiles were obtained by headspace solid phase microextraction, and PPG by solid sample analyses; and chemical analyses were performed using gas chromatography-mass spectrometry. Workers performed agonistic behaviors more frequently towards non-nestmate whole bodies, body parts and gland extracts, primarily those from the post-pharyngeal glands. Nestmate thoraces odorized with alien extracts were also recognized from aliens. Nestmate recognition ability persists for 12h and 24h after isolation, but decreases after 48h, suggesting that the chemical signal changes over time. Inter-colonial chemical analyses showed no differences in the PPG hydrocarbon profiles, while the relative proportions of MG compounds showed significant differences between colonies. These results showed that nestmate recognition was achieved by MG volatiles. Possibly, the PPG secretion works as a matrix that absorbs MG volatiles. We report, for the first time, some mandibular gland compounds for the genus Acromyrmex and for the tribe Attini group.
El reconocimiento de compañeras de nido es fundamental para la cohesión de la colonia en los insectos sociales. Las señales de reconocimiento de compañeras en Acromyrmex landolti fueron estudiadas mediante bioensayos de comportamiento y análisis químicos de los componentes de la glándula mandibular (GM) y postfaríngea (GPF). Los bioensayos de comportamiento fueron realizados usando cuerpos completos de hormigas, partes del cuerpo y extractos glandulares de GM y GPF de una compañera de nido y una intrusa en el centro de una trilla activa. Los comportamientos agonísticos de las obreras se clasificaron en exploración, ataque y mordida. Las obreras se mostraron más agresivas hacia los cuerpos completos, partes del cuerpo y extractos glandulares de las intrusas que hacia los de las compañeras de nido. Los volátiles glandulares se obtuvieron mediante la técnica de espacio en cabeza con microextracción en fase sólida, y los hidrocarburos de la PPG por análisis de muestra sólida. Se encontró que los volátiles de la GM conforman la señal de reconocimiento. No se encontraron diferencias intercoloniales para los volátiles de la GM. Posiblemente los hidrocarburos cuticulares actúan como una matriz que absorbe volátiles de la GM.
Subject(s)
Animals , Ants/physiology , Nesting Behavior/physiology , Pharynx , Submandibular Gland , Ants/classification , Gas Chromatography-Mass Spectrometry , Time FactorsABSTRACT
As glândulas mandibulares de operárias recém-emergidas, nutridoras e campeiras, rainhas virgens e fisogástricas, e machos maduros de Scaptotrigona postica Latreille foram estudadas histológica e morfometricamente. Estas glândulas apresentam diferenças histológicas características para cada idade e/ou função do indivíduo. De acordo com a morfometria conclui-se que as glândulas mandibulares possuem um ciclo secretor determinado, no qual a secreção começa a ser produzida nas operárias recém-emergidas, e acumula-se no citoplasma e reservatório da glândula das operárias nutridoras. Nas operárias campeiras o citoplasma encontra-se bastante vacuolizado, o que foi interpretado como resultado da eliminação da secreção. Rainhas fisogástricas apresentaram as maiores áreas celulares e nucleares, ao oposto dos machos, os quais apresentaram as menores áreas.
The mandibular glands of newly-emerged, nurse and forager workers, virgin and physogastric queens, and mature males of Scaptotrigona postica Latreille were studied under histological and morphometrical analyses. These glands present differences in their histology, according to the age and/or function of the individuals. The morphometric results showed that the mandibular glands have a very markedly secretory cicle, in which the secretion starts to be produced in newly emerged workers, being accumulated into the cytoplasm and reservoir in the nurses. In forager workers the cytoplasm presents many vacuoles, which are remaining of the secretion releasing. Physogastric queens showed the largest cellular and nuclear areas. On the contrary, the males presented the smallest ones.
ABSTRACT
The ultrastructural features of the ectal mandibular glands of the paper wasp Polistes versicolor are described. Theseglands contained a secretory portion and a sac-shaped reservoir. Muscle fibers were observed around the secretorycells close to where slender ducts arose to reach the reservoir sac. These fibers were probably involved in the releaseof secretion. The early secretory cells contained rough endoplasmic reticulum and Golgi complex with varying features,as well as the mitochondria necessary to sustain the energy requirements for the secretory activity. Smooth endoplasmicreticulum appeared only during the late stages of the secretion cycle. Synthesis and secretion occurred simultaneouslyand continuously within each cell, with the secretory cycle being essentially asynchronous throughout the gland. Thecells of the reservoir wall differed from those in other hymenopterans by their lack of a dense cuticle lining the lumen.These cells also produced lipids that probably will contribute to the ultimate composition of the secretion.
Subject(s)
Animals , Exocrine Glands , Salivary Glands/anatomy & histology , Salivary Glands/ultrastructure , Hymenoptera , Salivary Glands , Wasps/anatomy & histology , Insecta , Microscopy, Electron , Wasps/physiologyABSTRACT
Insect mandibular glands are exocrine organs that produce chemical substances known as pheromones that play an important role in intra-specific communication of insects. The mandibular glands of Apis mellifera, which are more highly developed in queens than in workers, present caste-specific polymorphism which seems to be regulated by the juvenile hormone (JH). These glands develop at the pupation stage, during which the titer of JH is higher in queens. In spite of this observation, application recounted here of juvenile hormone on 5th-instar workers' larvae of Apis mellifera did not produce a significant effect on the size of the mandibular glands. Therefore, we may conclude that the response of insect organs to the exogenous application of JH varies according to the type of organ, its developmental program, and its developmental stage, as well as to the amount of hormone applied.
As glândulas mandibulares são órgãos exócrinos, produtores de substâncias químicas denominadas feromônios, cuja função é atuar na comunicação intra-específica. Essas glândulas apresentam polimorfismo casta-específico, o qual parece ser mediado pelo hormônio juvenil (HJ), e são mais desenvolvidas na rainha do que na operária. Seu desenvolvimento ocorre durante a pupação e, em rainhas, os níveis de HJ são mais altos. Apesar disso, aplicação experimental de hormônio juvenil em larvas de 5º instar de operárias de Apis mellifera não produziu efeito significativo sobre o tamanho das glândulas mandibulares. Pode-se concluir que a resposta dos órgãos das abelhas à aplicação exógena do HJ varia segundo o tipo de órgão, o programa e a fase de desenvolvimento do órgão analisado e o volume do hormônio utilizado.
ABSTRACT
The purpose of this study is to investigate the origin of neurons and afferent fibers projecting to submandibular gland by means of retrograde transport of Cholera Toxin B Subunit (CTB). CTB was injected into the both side submandibular gland or left side submandibular gland. In the rat brain stem, neurons were labeled with CTB in superior salivatory nucleus (SSN), facial nucleus, caudal region of hypoglossal nucleus, lateral horn of spinal cervical segment and their afferent fibers in nucleus tractus solitarius. At the most rostal level of SSN, the labeled cells were seen in lateral aspect of pontine reticular formation. At the level of facial nerve that traverse the dorsal part of the spinal trigeminal tract, the labeled cells of SSN extended to the anterolateral direction of lateral aspect of reticular formation. At the level of facial nucleus, the labeled cells of SSN were seen in the area of caudal prologation of the same region of rostral ones, but decreased in cell number. In the facial nucleus, the labeled cells were confined in central part of facial nucleus. In the first and second spinal cervical segment, the labeled cells were seen in the intermediomedial nucleus of lateral horn. The labeled nerve fibers in nucleus tractus solitarius were seen at the level of the 4th ventricle which the medial border of the nucleus tractus solitarius meets. Injection of CTB into the left submandibular gland labeled their neurons on the left and right superior salivatory nucleus (SSN), but other labeled cells and fibers were localized only on the left side.