Wax Glands Research Articles

Secretion of squalene by ticks

The nature of the fluid secreted from the dorsolateral surface of certain ticks was analyzed chemically and by correlating secretory activity with the presence of glands. A waxy fluid flows from particular linearly arranged pores (“sagittiform sensilla”) that characterize metastriate ticks when their legs are pressure-stimulated. The secretion is released from a reservoir located beneath the cusp-like valves of the inner chamber of the gland and comprises almost 2% of the tick's body weight. It is replenished within 10 days, regardless of the water relationships of the tick. Gas chromatographic and mass spectral analysis demonstrate that its dominant component (at least 25% of non-volatile mass) is squalene. This pressure-stimulated, squalene-containing secretion of the “large wax glands” of metastriate ticks has the characteristics of a defense secretion.

Temporal and spatial patterns of wax secretion and related behavior in the division of labour of the honeybee (Apis mellifera capensis)

Current ethograms for honeybee behavior are hypothesized to consist of age-related cohorts of workers having a high probability of performing a small set of related tasks in a restricted portion of the nest. Wax secretion and wax working related activities were assayed in this light. It is shown that wax secretion is significantly affected by worker age and that bees between 3 and 21 days old form such a cohort. Comb building festoons, previously thought to be the site of wax secretion, represent only a small fraction of newly secreted wax in the nest. Wax secretion remains constant relative to age in the cohort but varies significantly with season as does bee participation in festooning behavior. Wax secretion and wax working are both definable in terms of time and space in the nest, the relative probability of activity changing with season. Secretion itself is constrained by the cyclical activity of the underlying wax gland complex.

Observation on the composition and biosynthesis of egg wax lipids in the cattle tick, Boophilus microplus.

The biosynthesis of wax lipids by Gené's organ, the egg waxing organ in ticks, was investigated. Gené's organ, a complex dermal gland system, applies a superficial wax layer to the eggs during oviposition which prevents desiccation and is essential for egg viability. The detailed anatomy and histology of the three gland cell types are unambiguously described. Serial sectioning of ticks showed that all three gland cell types are capable of contributing to the egg wax. The wax synthetic ability of these three gland types was characterized. The composition of wax lipids extracted from the surface egg wax, and from the three types of wax gland dissected from ovipositing ticks, was analysed using thin-layer and gas-liquid chromatography. Injection of ovipositing ticks with radiolabelled acetate resulted in the incorporation of the label into wax lipids by gland cells of Gené's organ. The egg wax was a complex mixture of long-chain alkanes and fatty acid esters. The gland cells contained a greater proportion of shorter chain alkanes than were present in the egg surface wax. Some unsaturated long-chain fatty acids were present, and these were more abundant in the gland cells than in the surface wax of oviposited eggs, suggesting that oxidation occurs after oviposition. The results confirm that the tubular glands, acinar accessory glands and lobular glands of Gené's organ all contribute to the egg waxes, although the lipid components differed in relative abundance. The results are also consistent with alkane synthesis from fatty acids in Gené's organ by a chain-elongation-decarboxylation pathway.

Synthesis and secretion of beeswax in honeybees

Summary — The ultrastructure of the cells of the wax gland complex in honeybee workers was studied in relation to the synthesis and secretion of beeswax. The hydrocarbon and fatty acid profiles of epidermal cells and oenocytes were determined in relation to the ages of the bees. Smooth endoplasmic reticulum (SER) is absent from both epidermis and adipocytes from adult emergence until the end of wax secretion. The oenocytes are rich in SER. The hydrocarbon and fatty acid content of the oenocytes, averaged for age, closely matches that of newly secreted wax. That the oenocytes are the probable source of the hydrocarbon fraction of beeswax is consistent with histochemical and autoradiographic data for honeybees and with biosynthetic data from other insects. The cyclical changes of organelles and chemical composition of the wax gland complex closely coincide with measured, age-related rates of wax secretion in honeybee workers.

Taxonomy based on chemical constitution: Differentiation of heavily Africanized honeybees from moderately africanized honeybees

Lavine, B.K., Ward, A.J.I., Han Jian Hwa, Smith, R.-K. and Taylor, O.R., 1990. Taxonomy based on chemical constitution: differentiation of heavily Africanized honeybees from moderately Africanized honeybees. Chemometrics and Intelligent Laboratory Systems, 8: 239–243. Heavily Africanized honeybees can be differentiated from moderately Africanized honeybees based on differences in chemical constitution. The test data (i.e. training set) consisted of 70 chromatograms of hydrocarbon extracts obtained from the cuticle, exocrine and wax glands of heavily Africanized and moderately Africanized foragers. Each chromatogram contained 65 peaks corresponding to a set of standardized retention time windows. However, only 13 of these 65 gas chromatographic (GC) peaks were used for discriminant analysis. The feature selection process that was employed to select these peaks was based on a priori considerations, e.g. well defined baseline, reliable integration counts. A discriminant function was developed from this set of 13 GC peaks using the linear learning machine. The linear discriminant correctly classified every chromatogram in the training set and also achieved a high classification success rate for the prediction set which contained 118 chromatograms.

Application of gas chromatography/pattern recognition techniques to the problem of identifying Africanized honeybees

Capillary column gas chromatography and pattern recognition techniques were used to develop a potential method for distinguishing heavily and moderately Africanized honeybees from European honeybees on the basis of differences in chemical constitution. The test data consisted of 232 chromatograms of hydrocarbon extracts obtained from the cuticle, exocrine, and wax glands of heavily Africanized honeybees, moderately Africanized honeybees, and European honeybees. Each chromatogram contained 65 peaks corresponding to a set of standardized retention time windows. A linear discriminant function, developed by a nonparametric pattern recognition procedure called the linear learning machine, correctly assigned the chromatograms to their respective classes: European or Africanized. The discriminant was then tested, using an external prediction set of 251 chromatograms. Two hundred forty-seven out of two hundred fifty-one prediction set samples were correctly classified. Since many samples in the prediction set were hybrids, these results clearly demonstrate that information derived solely from the nonisoprenoid hydrocarbons could correctly categorize the bee specimens as to race.

The formation of plasma membrane reticular systems in the oenocytes of an insect

Plasma membrane reticular systems (RSs) are infolds of the plasma membrane found in cells of several insect tissues that are not transporting epithelia. They form a subsurface reticular lymph space that may be involved in the loading and unloading of hemolymph carrier molecules. The development of a new RS during the fifth larval stadium has been studied in the oenocytes of Calpodes ethlius by scanning electron microscopy. The RS forms by the extension and progressive apical fusion of cell processes leaving a reticular lymph space below. Reticular system formation occurs in a front moving over the cell surface. The RS made in the 4th stadium persists through the moult to the 5th stage but diminishes for the next 3 days. A new intermoult RS then forms very quickly. Its time of formation follows the commitment ecdysteroid peak rather than the beginning of secretion by the wax glands. This new 5th stage RS is maintained during the period of intermoult synthesis, after which it declines and is nearly absent by the time of pupation.

Colopha hispanica sp.n. (Homoptera: Aphidoidea: Pemphigidae): an unusual endophytic aphid living inside the stems of Scirpus holoschoenus (Cyperaceae)

Abstract. A new aphid species of the genus Colopha (Pemphigidae: Eriosomatinae), Colopha hispanica is described from Spain. The apterae differ from those of other species of Colopha in the shortness of their antennae and legs, in the greater number of their wax glands and in the underdevelopment of the setal socket on the forelegs. These aphids live inside the stems of Scirpus holoschoenus (Cyperaceae); this is the first record of a truly endophytic aphid. The adults are immobile. C. hispanica is compared with the other known species of Colopha, with Kaltenbachiella pallida, a similar species also found in Spain and with Gharesia polunini, a primitive species of Eriosomatinae. The distribution and host plants of Colopha species are reviewed and discussed.

Fine structure of wax glands, wax morphology and function in the female scale insect, Pulvinaria regalis canard. (Hemiptera : Coccidae)

The fine structure of wax glands and their secretions are described; their function is discussed in the female scale insect Pulvinaria regalis Canard (Homoptera : Coccidae). The quinquelocular wax glands, composed of only one type of glandular cell, whose cytoplasm contains a well-developed smooth endoplasmic reticulum, are associated with stigmatic furrows. They produce white hydrophobic waxy secretions that protect the air passage going to the spiracles. Both the multilocular wax gland, formed from one type of glandular cell producing white C-shaped curled filaments, and the tubular wax gland, comprised of 2 types of glandular cell (lateral cells with well-developed SER and one central glandular cell with well-developed RER), produce long white filaments that are associated with the constructions of the ovisac. In order to avoid honeydew contamination, the scale insect propels excrement away from the body by an anal apparatus. The 6 setae of this device, which play the role of a catapult, are covered by wax filaments produced by numerous small glands whose pores open onto the anal ring.

Ultrastructure comparee des glandes tegumentaires de treize familles de cochenilles (Homoptera : Coccoidea)

Wax glands and their secretions are described in 13 families of scale insects. The wax-producing cells are characterized by a well-developed smooth endoplasmic reticulum and cuticular specializations (filaments, tubular structures, and epicuticular pores), which allow passage of the secretion to the outside. Four basic types of secretions were observed: long filaments without lumina ( Cryptococcus); long filaments with lumina ( Eriococcus); short curled filaments ( Llaveia); amorphous ( Ceroplastes, Kerria). An analysis of the components of the secretion of Llaveia revealed that the major component, an ester of fatty acid with a long chain C 68, comprises approximately 98% of the secretion. This comparative ultrastructural study of the wax glands shows an evolutionary trend from the primitive Monophlebidae to the higher families in terms of successive numerical reductions in both the wax glands and the glandular cells. The modifications of the shapes and the structures of the pore, the ductule and the duct are observed from Monophlebidae to Phoenicococcidae. The number of types of wax glands increases up to the family Coccidae and then shows a successive regression. The modifications of the wax gland system in scale insects shows an increasing complexity, followed by a regression, which leads to uniformity and concentration of these glands.

Ultrastructure comparee des glandes tegumentaires des cochenilles diaspines (Homoptera : Diaspididae)

This study describes the fine structure, function and secretion of the integumentary glands of armored scale insects (Homoptera : Diaspididae). There are 2 types of glandular organizations: (1) glands with ducts, involved in the production of the protective scales; (2) glands without ducts (e.g. peristigmatic glands, protecting the orifices of the spiracles or perivulva glands, protecting the eggs and the vulva area). The glands with ducts are composed of 5 – 6 cells. The central glandular cell has a well-developed rough endoplasmic reticulum, which secretes a glyco-proteinaceous substance; the 2 lateral glandular cells have a well-developed smooth endoplasmic reticulum (SER), which secretes the waxy component of the secretion. The secretion, a white ribbon made up of 2, rarely 3, hollow strands stuck together, the structure of the duct, and especially that of the spinneret responsible for the shape and structure of the secretion, are characteristic of the family Diaspididae. The glandular cells of the peristigmatic and perivulva glands are of only 1 type and have a well-developed SER. The secretion, comprised of long filaments, passes from inside to the outside through a special cuticular structure, having respectively 3 components: filaments, tubular structure and epicuticular pores. The evolution of the wax gland system within the family Diaspididae shows a numerical reduction and concentration. The numerically more reduced, localised and uniform glandular system is found among the Aspidiotini, which are considered as more evolved.

Structure et Fonctions des Glandes Tégumentaires de Cochenilles Pseudococcines et de Leurs Sécrétions

SummaryA comparative ultrastructural study of wax glands of the Pseudococcidae showed three general types of glandular organization and their fonctions: 1, gland without duct constitued only one type glandular cell which has a well-developped smooth endoplasmic reticulum, secretes lipoproteic substance. 2, gland with duct, 3, gland coupled. The last two types have a central glandular cell, which has a well-developped rough endoplasmic reticulum, secretes a glycoproteinaceousus substance and the lateral cells which have a well-developped SER, secretes lipoproteic substances.The cuticular specializations (filaments, tubular structure and epicuticular pores) linked to the emission of the secretion is described.The various pores and ducts and the secretions were studied with a scanning electron microscope and the mechanism of the formation of the secretion was precised. Three basic types of secretion were determined: long filaments longitudinally ribbed on the outside; short curled filaments hollowed out like a gutter; flat microfilaments edged on one side and intertwined in a spiral. The basic function for all three types is that of protection against immersion, dessication, natural ennemies and honeydew.

A function for plasma membrane reticular systems

The basal surface in transporting epithelia is infolded in a way that encourages the formation of standing gradients. Many insect cells have a similar infolded reticular system (RS) although they are clearly not transporting epithelia. These cells are like one another metabolically in that they sequester lipid from hemolymph lipophorins (lipid transporting proteins). Dietary lipids enter the hemolymph from the midgut RS which may be an adaptation for lipophorin loading. The plasma membrane reticular system of tissues metabolizing lipids (fat body, wax glands, oenocytes, lenticles) may be an adaptation for lipophorin reception and unloading. Cationic ferritin (pI 8.5) shows all RSs are covered by a lamina functioning as a negatively charged sieve. The basal plasma membrane leading to the RS is also negatively charged. The RS is a container with charged entrances that would be expected to affect the composition of the contents. Midgut cells release lipid particles into their RS. The particles are positively charged since in tracer studies they associate with anionic but not cationic ferritin. Lipophorins are anionic. The electrostatic binding of lipid to lipophorin would make it less anionic and more likely to leave the RS when loaded, thus carrying lipid to the hemolymph. Conversely, at the destination RS, loaded lipophorin would penetrate more easily than unloaded. A change in charge with unloading would be expected to alter the equilibrium between entering and leaving lipophorin, causing protein concentration in the RS of lipid receiving tissues as has been observed in the fat body. Reticular systems may thus be reaction vessels for interactions between carrier proteins and their load.

Ultrastructure of the wax-gland system in subterranean scale insects (homoptera, coccoidea, margarodidae).

The ultrastructure of wax glands (integumentary, stigmatic, and peristigmatic glands) was investigated in larvae, cysts, and adult females and males of species belonging to the genera Porphyrophora, Sphaeraspis, and Eurhizococcus. The general organization and cytological characteristics are similar for all glands studied. Each gland is composed of a single layer of 8 to 40 cells. The glandular cells are characterized by a very large quantity of smooth endoplasmic reticulum which forms dense zones throughout the cytoplasm, but is always placed near the collecting canals in the presence of mitochondria. Each cell has a central canal reservoir which penetrates it deeply and gives rise to a large number of lateral collecting canals, formed by the invagination of the apical plasma membrane. The canals open into a subcuticular cavity forming a common reservoir in which the secretion is accumulated. This reservoir is covered by a modified cuticle formed from the endocuticle and the epicuticle. The endocuticle is composed of a network of fine tubular structures and has many filaments on its surface. The epicuticle is perforated by numerous pores. There is no cuticular duct. The secretion crosses the cuticle in three successive steps. First, it passes through the filaments, then through fine tubular structures of the endocuticle, and finally through the epicuticular pores.

Fine Structure of the Wax Gland in a Scale Insect, Eriococcus lagerstraemiae KUWANA (Homoptera : Ericoccidae)

The dorsal surface of the female Ericoccus lagerstraemiae is covered by a thick shield made of long, thin, tubular wax filaments. The integumentary wax gland producing these filaments are distributed throughout the dorsal surface. Each gland is composed of a cuticular duct, one large main cell, six lateral cells and a ductule cell. The main cell stores in its reservoir a massive secretory substance which shows positive reactions to the tests for lipids, proteins and carbohydrates. The cytoplasm of the main cell contains well-developed rough-surfaced endoplasmic reticulum and numerous secretory globules which are discharged into the lumen of the reservoir. The lateral cells may also contribute some secretion to the covering wax filament, but their precise role is unknown. The ductule cell contains a thin cuticular ductule which is formed by the cell itself. The formative mechanism of the tubular filament is of special interest. The amorphous secretory substance is transported from the main cell to the bottom of the cuticular duct via the ductule, met by the secretion of the lateral cells there, and then is molded into a tube by the trough-shaped cast cuticle present there.

Biosynthesis of wax in the honeybee, Apis mellifera L.

The composition of the cuticular wax of the honeybee is quantitatively different from that of the comb wax. The major component of the cuticular lipids is hydrocarbon, which comprises 58% of this wax. In contrast, hydrocarbon comprises only 13–17% of the comb wax, and monoester is the largest component ( Tulloch 1971). The major fractions of the cuticular wax were analyzed by gas-liquid chromatography, and were shown to be qualitatively similar to those of the comb wax. The incorporation of injected radio-labelled acetate into hexane extractable wax by worker honeybees not actively producing comb wax resulted in the recovery of much of the radioactivity in the hydrocarbon fraction. In insects actively producing comb wax, a higher percentage of radioactivity was recovered in the monoester fraction. A dramatic effect of age on the distribution of radioactivity from acetate into the various wax fractions from honeybees studied in the summer months was observed. In insects from eleven to eighteen days following emergence to adults, the major wax component synthesized was monoester, whereas in younger and older insects, hydrocarbon was the major wax component formed. Both in vivo and in vitro experiments using insects actively producing comb wax showed that the abdomen produced significant amounts of monoester, hydrocarbon, and other esters, whereas the thorax synthesized mostly hydrocarbon. These data show that the epidermal cells and wax glands each produce a wax with a distinct composition, and that the age and seasonal differences observed in wax synthesis are due to the presence or absence of active wax glands.

Wax synthesis by an enzyme system from the honey bee

1. 1. A cell-free system prepared from the worker honey bee, containing enzymes from active wax glands, is described which readily incorporated a long-chain fatty alcohol, [1- 3H]tetracosanol (24:0), into wax esters. About 16% of the label is recovered in the wax ester fraction after 1 hr of incubation at 37°C. 2. 2. ATP, CoA, Mg 2+, and a pH of 7.1 are required for maximum activity. The fatty acid component of the wax ester is derived from the endogenous lipids of the enzyme preparation. The wax-synthesizing enzyme is not highly specific for the longer chain fatty alcohols, since hexadecanol (16:0) was also incorporated into wax by the system. The system is highly sensitive to detergents. 3. 3. The findings indicate the monoester wax component of beeswax is biosynthesized by the reaction of a long-chain alcohol, such as tetracosanol, with a fatty acyl-CoA.

Fine structure and metamorphosis of the wax gland cells in a psyllid insect, Anomoneura mori schwartz (Homoptera).

The fine structure of the wax gland of Anomoneura nymph and its metamorphic change were investigated. In the nymph, this organ encircles the anus, and consists of two kinds of cells, derived from epidermal cells: (1) very tall, slim wax cells, which produce and secrete the wax, and (2) flat interstitial cells found among the wax cells. The whole gland is covered by a wax-secreting cuticle with a delicate surface sculpture. Each wax cell has a long, wide duct which opens at the cuticle and penetrates the entire cell. Its cytoplasm is rich in mitochondria and smooth endoplasmic reticulum while that of interstitial cells contains rough endoplasmic reticulum. During each nymphal molt, the cluster of primordial wax gland cells - derived from the epidermis - proliferates rapidly and forms the gland of the next instar. The gland of the preceding instar meanwhile degenerates. Interstitial cells play an important role in cuticle formation and shedding at each molt. These cells alone produce and deposit the new cuticle of the next instar; the wax cells, specialized for wax production, cannot produce cuticle. The apical portion of the wax cell is cut off from the main cell body by growth of the surrounding interstitial cells. Thereafter, the wax cells degenerate, resulting in the rapid disappearance of the previous instar's wax gland. Adults lack this gland entirely.

Bionomics of Haplaxius crudus (Homoptera: Cixiidae) 12

Haplaxius crudus nymphs feed and live in the thatch layer and on the roots of St. Augustinegrass, bahiagrass, centipedegrass, bermudagrass, paragrass, yellow nutsedge, broomsedge, foxtail, and other sedges. Secretions from the abdominal wax glands protect the nymphs from wetness, disease, and predators. Average nymph size after each molt at 24°C was 0.80, 1.35, 1.80, and 2.47 mm for 4 respective molts. No differences in size were noted at 30°C. Wingpad development between each molt is a unique characteristic for identifying nymphal age. All nymphal instars developed more rapidly at 30° than at 24°C. Cool temperature (15°C) had an adverse effect on nymph development. Large nymphs survived an extended period without feeding. Eggs were 0.5–0.6 mm in length and 0.15–0.20 mm in width with one blunt end. Parthenogenic reproduction was not observed. The mean life span for adult males on St. Augustinegrass was 7.3 days and 7.8 days for adult females. The mean generation time at 30°C was 52.6 days and 80.8 days at 24°C. The adult H. crudus survived 37 and 50 days on coconut and veitchia palms, respectively. Coconut cultivars differed significantly in numbers of H. crudus attracted. The numbers of adults attracted to palm differed significantly among seasons. H. crudus was found in palms more in the evening hours than in the morning hours.

The existence of two species of Euceraphis (Homoptera: Aphididae) on birch in Western Europe, and a key to European and North American species of the genus

Abstract. Aphids formerly regarded as Euceraphis punctipennis (Zetterstedt) are distinguished as two species, E.punctipennis and E.betulae (Koch), on the basis of cytological and morphological differences. E.punctipennis is primarily associated with Betula pubescens Ehrh., and E. betulae with B.pendula Roth. Seasonal variations in morphometrics, pigmentation and development of wax glands in the two species are described and compared. A key to European and North American species of Euceraphis is provided.