Hormonal control of female sex pheromone biosynthesis in the redbanded leafroller moth,Argyrotaenia velutinana

Pheromone biosynthesis in female redbanded leafroller moths (RBLR) is under control of a neuropeptide produced in the brain. A bioassay consisting of isolated abdomens was developed to test the mode of action of the pheromone biosynthesis activating neuropetide (PBAN). Pheromone titer and incorporation of radiolabeled acetate into pheromone could be monitored with this bioassay. Synthetic PBAN with sequences identical to PBAN isolated from Heliothis zea and Bombyx mori were active in inducing synthesis of pheromone in RBLR. Removal of the ventral nerve cord in isolated abdomens did not inhibit the action of PBAN. Small amounts of PBAN-like activity was found in hemolymph collected from normal females but not from decapitated females. Severing the VNC in vivo in normal females did not lower the pheromone titer. These data indicate that PBAN is released into the hemolymph and then travels to its site of action. A two-fold increase in both pheromone titer and radiolabeled acetate incorporation upon incubation with PBAN was shown with isolated pheromone glands. However, the differences between control and PBAN-induced values were smaller than those obtained with the isolated abdomen culture bioassay where a seven-fold increase was observed. A decrease in pheromone titer was seen upon the in vivo removal of the corpus bursae from normal females. Removal of the corpus bursae in the isolated abdomen cultures also abolished the activity of PBAN. However, cutting the cervix bursae and leaving the corpus bursae in the abdomen culture increased both titer and radiolabeled acetate incorporation into pheromone without the presence of PBAN. An aqueous extract made from the corpus bursae of 5-day-old females was also active by itself in inducing pheromone biosynthesis in the isolated abdomen cultures. Experiments performed using newly emerged females confirmed that the corpus bursae extracts will induce pheromone biosynthesis. These results indicate that both PBAN and the corpus bursae are involved in controlling pheromone biosynthesis in RBLR.     

Morphology of the sternal and tergal glands producing the sexual pheromones and the aphrodisiacs among the cockroaches of the subfamily oxyhaloinae

Among cockroaches in the subfamily of Oxyhaloinae, the adult males produce two essential and successively active chemical signals: the sex pheromone attracting females from a distance secreted by the sternal glands, and the aphrodisiac required for mating which is secreted by the tergal glands. The adult males of the seven species studied, Nauphoeta cinerea, Henschoutedenia flexivitta, Leucophaea maderae, Jagrehnia madecassa, Gromphadorhina portentosa, G. laevigata, and G. chopardi, possess well-developed sternal and tergal glands whose number varies according to the species and methods of mating (three to six sternal glands and four to seven tergal glands). These glands are basically composed of type three glandular units (glandular cell + duct cell) and type 2 cells (modified oenocytes) which exhibit no significant external cuticular modification except for tergite 2 of L. maderae. The extreme variance in development of these glands can be linked to sexual behavior. The hypothesis put forward here is that of a regressive evolution of the tergal glands, related to a modification of the role played by the aphrodisiacs which they secrete.     

Structure development and evolution of the male pheromone system in some noctuidae (Lepidoptera)

Pheromone systems from seven species of noctuid are examined. Much of the structure of scales from the wings and/or the abdomen is interpreted as a modification for secretion or release of a pheromone. Scales with an extremely complex surface provide a large evaporation surface, while those connected to secretory cells show less superficial folding than body-covering scales. The development of the secretory gland and diseminatory scales in Mamestra configurata is followed from the exuvial pharate adult stage to emergence. Both components are paired and develop from epidermal cells lining a pair of large lateral invaginations. They may have resulted through division of a group of less specialized cells that originally combined the function of pheromone production and release.     

Development of functionally competent cabbage looper moth sex pheromone glands

Unlike some moths, pheromone production in Trichoplusia ni is not regulated by a pheromone activating neuropeptide. Rather, competency to produce pheromone apparently is linked with changes in the ecdysteroid titer that occur late in metamorphosis. In contrast to adult pheromone glands, glands from pharate adults 2 days before eclosion were non-competent, and (1) had undetectable levels of the pheromone, (Z)-7-dodecenyl acetate, and pheromone-specific intermediates, (2) showed little or no conversion of radiolabeled substrate to product in enzyme assays of fatty acid synthetase, Δ11 desaturase, and acetyltransferase, and (3) failed to incorporate radiolabeled acetate into pheromone in gland culture. Glands 1 day before adult eclosion exhibited low titers of pheromone and the intermediate, (Z)-11-hexadecenoate, and showed low levels of radiolabeled acetate incorporation into pheromone in gland culture. By the time of adult eclosion, the gland was fully competent. Precocious development of pheromone gland competency was induced by removing the head and thorax from pupae 2 days before adult eclosion. This effect appears to result from the reduction of ecdysteroid, since it was blocked by the administration of 20-hydroxyecdysone. This ability to manipulate the development of the pheromone gland was restricted to a critical period, since removal of head and thorax from younger pupae did not induce pheromone gland competency, and administration of 20-hydroxyecdysone to older pupae did not block its onset. In addition to differences in competency, early pharate and adult glands exhibited dissimilarities with respect to (1) the types of proteins synthesized in gland culture, and (2) the types of proteins translated from mRNA in vitro.     

Determination of the site of pheromone emission in the virgin females Culicoides nubeculosus Meigen (Diptera: Ceratopogonidae)

The zone of emission of the sex pheromone from the body of Culicoides nubeculosus was investigated. The amount of pheromone emitted was evaluated by counting the number of matings between males and females exposed to a flow of air coming from a chamber containing virgin females. The number of matings is higher than that recorded when the air flow comes from an empty chamber (control). Three parts of the body were examined: head, thorax and abdomen. Each part was studied by neutralizing the effect of the others. The head was neutralized by decapitation and the females continued to emit pheromone. The head is, therefore, not indispensible for pheromone emission. The roles of the thorax and abdomen were studied by coating these with paraffin wax. When the thorax is coated, pheromone emission continues, but when the abdomen is coated, it stops. It appears that the abdomen alone is responsible for emission of the sex pheromone.     

Location,morphology and histology of sex pheromone glands of the female gypsy moth, Lymantria dispar (L.)

Scanning electron microscopy, histology and a male wing fanning bioassay were used in this study to locate the sex pheromone-producing glands of the female gypsy moth, Lymantria dispar. When exposed to female sex pheromone, adult males exhibit a strong wing fanning behaviour prior to take off. We found that adult males showed positive response to calling females and to tissue extract from both dorsal and ventral portions of the intersegmental membrane between 8th and 9th-abdominal segments. A typical male response usually starts with elevation of antennae, movement of head in different directions, walking, wing fanning and onset of search flight. Histological and scanning electron microscopic studies suggested that the sex pheromone glands are located on the dorsal and ventral aspects of the intersegmental membrane. The glands appear as two highly convoluted integumentary areas with hypertrophied glandular epidermal cells.     

Protein metabolism by the salivary glands and other organs of the larva of the blowfly, Calliphora erythrocephala

Protein metabolism in salivary glands, gut, haemolymph, and fat body during the last larval instar of the blowfly, Calliphora erythrocephala, has been investigated. In salivary glands, protein release, protein synthesis, amylase, and pepsin-like protease activity were maximal in 6 day larvae, this being at a time when the larvae had finished feeding. All these functions declined in glands from the rounded-off white puparial stage (R.O.) while acid phosphatase activity rose throughout the third instar to a maximum at the R.O. stage, Glands from 6 and 7 day larvae released protein which on disk gel electrophoresis separated into four minor bands and two major bands one of the latter possessing protease activity.In the gut, pepsin-like protease activity was maximal in 4 day larvae after which it fell rapidly thus following the feeding pattern of the larva in contrast to that in the salivary glands which did not.In vitro experiments showed that protease was released from 6 day glands through the basal membrane of the cells and not via the duct. A pepsin-like protease was also found in the haemolymph and fat body, the activity in the fat body rising rapidly during the latter part of the third instar, a rise which is attributed to the fat body sequestering protease from the haemolymph. Acid phosphatase activity in the fat body was maximal in 5 day larvae indicating that this enzyme was synthesized early in the third instar. It was shown that fat body sequestered ¹⁴C-labelled protein synthesized by and released from the salivary glands, most of the ¹⁴C activity being associated with a 600 g precipitable, acid-phosphatase rich fraction.It is proposed that in late third instar larvae the salivary glands function as glands of internal secretion, releasing protease into the haemolymph, which is then sequestered by the fat body (and perhaps other tissues) and is subsequently used in the lysis of the tissues at the time of metamorphosis.     

Selectivity and neuroendocrine regulation of the precursor uptake by pheromone glands from hemolymph in geometrid female moths, which secrete epoxyalkenyl sex pheromones

Macrolepidopteran female moths in families such as Geometridae produce epoxyalkenyl sex pheromones, which are biosynthesized via epoxidation of polyunsaturated hydrocarbons in their pheromone glands. The precursors, however, are expected to be produced outside of the pheromone glands, probably in oenocytes or in the fat body, and transported to the glands via hemolymph. Based on these facts, the selectivity of the epoxidation substrates and of the precursor uptake by pheromone glands was examined with two geometrid species, Hemerophila artilineata and Ascotis selenaria cretacea, using binary mixtures of deuterated precursors and their analogs, which were topically applied to the pheromone glands or injected into the abdomen. GC-MS measurements of pheromone extracts showed equal epoxidation of two polyenes, indicating a low selectivity for both processes, while the epoxidation proceeded at only one double bond specific to each species. This result makes it possible to conclude that the formation of species-specific epoxyalkenyl pheromones results from the rigid formation of polyunsaturated precursors and their epoxidation at a fixed position. Next, the neuroendocrine regulation of these processes was studied with in vivo and in vitro experiments using decapitated females. The epoxy pheromones disappeared completely within 36 h of decapitation, and epoxidation of the injected precursors was not detected in the decapitated females, which restarted the reaction by treatment with a pheromone biosynthesis-activating neuropeptide (PBAN). The precursors topically applied to glands of the decapitated females, however, were converted into epoxy pheromones without PBAN, indicating that this neuropeptide hormone accelerated the precursor uptake by pheromone glands but not the epoxidation already underway in the glands.     

Ultrastructure of the glands producing sex pheromones of the male Nauphoeta cinerea (Insecta,Dictyoptera)

Summary The abdominal glands described here play a decisive role in the typical sexual behavior of Nauphoeta cinerea. Unlike other cockroaches, the males of this species produce two successive chemical signals: the sex pheromone itself, produced by the sternal glands, attracts the female from a distance, and the aphrodisiacs, secreted by the tergal glands, are licked by the female who is thus in a favorable position for mating. The well developed glandular apparatus is composed of 5 sternal glands (St3 to St7) and 7 tergal glands (T2 to T8). These glands appear as a thickening of the epithelium without significant modification of the external cuticle. The glandular epithelium is made up of several kinds of cells: ordinary epidermal cells (which only exist in the sternal glands), cells with microtubules, type 2 cells (oenocytes), and especially type 3 glandular units (composed of a secretory cell and a canal cell). The products secreted by the sternal glands are chiefly volatile products and fatty acids and those secreted by the tergal glands are primarily fatty acids and proteins. In this work, the relationship between the cytology of the glandular cells and the nature of the secreted products is discussed.     

Morphology of the reproductive system and antennal lobes of gynandromorphic and normal black cutworm moths,agrotis ipsilon (Hufnagel) (Lepidoptera : Noctuidae)

Sexually dimorphic characteristics of a bilaterally asymmetric gynandromorphic black cutworm moth, Agrotis ipsilon (Hufnagel), were compared with those of normal males and females. On one side of the body, the gynandromorphs wings were larger and darker than on the other side, and the antenna was filiform. On the other side of the body, the wings were smaller and lighter in color, and the antenna was pectinate. Females were usually larger and more pigmented than males. Female antenna were filiform and those of males pectinate. At the tip of the abdomen, the gynandromorph had 2 valves, as normal males do, but the one on the female side was smaller. The antennal lobes of the gynandromorphs brain included only ordinary glomeruli on the female side, and ordinary glomeruli plus a partially developed macroglomerular complex (MGC) at the base of the antenna on the male side. Normal female antennal lobes contained only ordinary glomeruli. Normal male antennal lobes contained ordinary glomeruli and a fully developed MGC, consisting of one large and 3 smaller glomeruli. In the gynandromorph, female reproductive organs were partially developed or absent. A portion of the oviduct was missing together with several ovarioles, and no spermatheca or seminal duct were found. The male reproductive track was complete, except for the paired structures, which in the gynandromorph were single. Normal females had paired accessory glands and ovaries, and single oviduct, bursa copulatrix, and spermatheca. Normal males had fused testes, paired accessory glands, and a single ejaculatory duct and aedeagus. The gynandromorph assumed a calling posture and attracted one male, but it did not respond to the pheromone from females.     

Localization and fine structure of the female sex pheromone-producing glands in Bruchidius atrolineatus (PIC) (Coleoptera : Bruchidae)

The sex pheromone glands of female Bruchidius atrolineatus (Coleoptera: Bruchidae) have been localized by recording the electric response of the antenna of males subjected to a stream of air, containing the volatile sex pheromone (electroanntennography-EAG). Some 50 unicellular glands are distributed irregularly in the ventral and dorsal intersegmental membranes situated at the extremity of the pygidium, each gland containing a short ductule with an evacuation pore, 0.5–1 μm in diameter. The receiving canal is composed of a network of fine epicuticular filaments. The glands are type 3. The ultrastructure of these sex pheromone-producing glands is described in females whose production-emission activity had been previously verified with EAG. Deep basal invaginations and inflated intercellular spaces indicate the transport of substances from the hemolymph to the gland cells. The presence of numerous elongated mitochondria, diverse inclusions, vesicles containing crystalline bodies, and abundant apical microvilli, all reveal elevated cellular activity, which is never observed in young or diapausing females that do not produce sex pheromone. The ultrastructural differences in different types of females (sexually active or diapausing), combined with comparative EAG recordings obtained with intact females or those in which the suspected glandular zone was masked, made it possible to localize the glands.     

Biosynthesis of the acetate ester precursor of the spruce budworm sex pheromone by an acetyl CoA: Fatty alcohol acetyltransferase

The biosynthesis of 11-tetradecenyl acetate, the major storage precursor of the aldehyde pheromone of Choristoneura fumiferana, the eastern spruce budworm, has been found to be catalyzed by an acetyl-CoA: fatty alcohol acetyltransferase. In vitro, acetyltransferase activity was found almost exclusively in extracts from the pheromone producing gland, and could be demonstrated in vivo by topical application of [¹⁴C]tetradecanol to the glands. Moreover, the activity was under developmental regulation, being low before and immediately after emergence of the moths from the pupal stage, and rising to a maximum in concert with the increase in glandular pheromone levels. Maximum activity with saturated alcohols was observed for acceptors of 12 to 15 carbons in chain length, with higher activities being found for the cis or trans monounsaturated analogs. The specificity of this enzyme with respect to substrate, morphological location and developmental regulation, indicates that it plays a key role in regulation of pheromone biosynthesis.     

The morphology of the sex pheromone gland in Drosophila grimshawi

The morphology of a sex pheromone-producing gland found in the abdomen of Drosophila grimshawi males was studied by light and electron microscopy. This gland, consisting of two intra-anal lobes, contains cells that resemble those of other insect pheromone glands. However, in contrast to many other insect pheromone glands that release pheromone through the cuticle, cells of the intra-anal lobes secrete into a canaliculi-duct system that empties into the anal region. The liquid secretory product flows along the surface of the intra-anal lobes and is brushed onto the substrate by fingerlike projections on the lobes' surfaces.     

Cell differentiation during the ontogeny of larval salivary glands of the fly, Telmatoscopus albipunctatus

Using the larvae, pharate pupa, and pharate adults of the moth fly, Telmatoscopus albipunctatus, histological and ultrastructural features of the salivary glands were investigated. The gland lumen contains a milky secretion from the first instar. This secretion continues to ccur at all subsequent developmental stages; with the onset of the pharate pupal stage, however, the secretion becomes transparent and rather viscous. Histochemical tests revealed that it is mainly proteinaceous. Glands from the same developmental stage may respond differently to PAS-reaction.Various cell organelles were compared at consecutive stages of larval development and of secretory activity of the salivary glands. In first and second instar larvae autophagic vacuoles are virtually absent in the salivary gland cells. They were occasionally found in the third instar, when they appear to be engaged in the process of organelle turnover. Histolysis of the larval glands is initiated towards the close of the fourth instar when the number of autophagic vacuoles starts to increase. Simultaneously, the cytoplasm, previously full of ribosomes and endoplasmic reticulum, starts losing these structures. At the beginning of the pharate adult stage, the cytoplasm becomes practically devoid of all structures other than those engaged in autophagy.Polyteny of the chromosomes during ontogeny of the larval salivary glands is also discussed.     

白蚁信息素研究进展

白蚁是最古老的社会性昆虫, 其社会性的维持需要信息素的相互作用。本文回顾了近年来国内外白蚁信息素研究的最新进展, 内容涉及白蚁踪迹信息素、 性信息素、 告警信息素和促食信息素的功能、 化学成分及产生信息素的外分泌腺。白蚁分泌信息素的腺体主要有背板腺、 腹板腺、 后腹板腺、 额腺和唾腺。绝大多数白蚁信息素是挥发性物质。白蚁在化学通讯上存在节俭策略, 即同一种化合物由不同的白蚁种类的不同外分泌腺分泌, 可具有不同的功能。总结了各类信息素在白蚁物种间、 同一物种的品级间和性别间的异同和作用方式, 强调了白蚁信息素的反应阈值、 最佳浓度、 有效期和物种特异性对其功能的影响。目前对白蚁信息素的研究尚处于起步阶段, 其研究成果对等翅目系统发育研究和白蚁防治具有重要的意义。文章最后展望了白蚁信息素在白蚁防治上的应用前景。     

Secretory and structural changes in the parotid salivary gland of sheep and lambs after parasympathetic denervation.

The effect of the parasympathetic nerve supply on the development of the parotid gland in the immature lamb and its maintenance in the adult sheep has been investigated by unilateral postganglionic denervation. Seventy-seven to ninety-three days after denervation secretory activity of the gland was examined and material taken for histological examination. The adult denervated glands secreted at lower rates than the innervated and their atropine-resistant secretory flow was reduced to as low as one fifth of that of the innervated glands. In two lambs an atropine-resistant flow did not develop in the denervated glands: in another two, flows of saliva from the denervated glands were present but were much less than in the contralateral innervated glands. After denervation glands were, with one exception, smaller than the contralateral innervated glands. The acinar cells of the denervated adult and lamb glands were smaller than the cells of the innervated glands but similar in size to those of 7-14 day old unoperated control lambs. Acinar cells in denervated glands had periodic acid Schiff staining material but the staining reaction to pyronin-methyl green was similar in the innervated and denervated. The results indicate that the integrity of the parasympathetic innervation is essential for the development of the parotid gland of the sheep and for its maintenance in the adult animal.     

Development of the anal vesicle, salivary glands and gut in the egg-larval parasitoid Chelonus inanitus: tools to take up nutrients and to manipulate the host?

Larvae of endoparasitoids undergo extensive morphological changes and often have special features to allow their development inside the host. We present the first detailed study on the development of the anal vesicle and the gut. The analyses reveal that the anal vesicle is first seen on the dorsal side of the abdomen as an internal structure covered by a membrane. The morphology of the abdomen then changes intensively: new segments are formed and the anal vesicle develops from a crest of large cells to a protrusion. Towards the end of the first instar, the anal vesicle is fully evaginated and no longer covered by a membrane; the large epithelial cells have microvilli on their apical side which suggests uptake of nutrients from the host's haemolymph. When the larva has moulted to the second instar, the ultrastructure of the anal vesicle begins to change and shows signs of degeneration. In this stage the epithelium of the midgut is fully developed and has a brush border which suggests that nutrient uptake occurs now primarily through the midgut. The anal vesicle then degenerates completely. The salivary glands are prominent already in first instar larvae and appear to produce and release a host regulatory 212 kD protein.     

花背蟾蜍蝌蚪皮肤的结构与发育

为研究花背蟾蜍(Bufo raddei)蝌蚪在变态发育期皮肤的显微结构特点,选取G19、G22、G26、G36、G41、G43和G46共7个发育期蝌蚪的连续石蜡切片及成体的背部皮肤切片,采用H.E和AB-PAS染色方法,观察了皮肤各层结构的发育时序并进行了相应的测量.结果表明,在G19、G22和G26蝌蚪表皮均为1层细胞;G36蝌蚪皮肤细胞形态和层数在背腹部出现了显著的区别;在G41基本完成了表皮2层细胞的构建;G43期完成完整的真皮构建,其中分布有毛细血管和2种皮肤腺.G46皮肤在厚度、腺体和毛细血管分布等方面表现出了明显的区域性差异,并与成体皮肤结构有明显的差别,显示出蝌蚪在发育过程中皮肤结构的变化与其生存环境之间紧密的关联性.     

腔阔盘吸虫尾蚴及后蚴穿刺腺等腺体的组织化学及其功能的初步研究

本文报道应用组织化学反应方法初步观察了腔阔盘吸虫(Eurytrema coelomaticum)尾蚴及后蚴体中单细胞腺的组织化学成分及其生理功能。尾蚴的5对大单细胞腺主要分泌粘蛋白、酸性粘多糖及微量碱性蛋白质,当子胞蚴被排到外界时,此腺体物质分泌出充满子胞蚴内囊腔并包被着各尾蚴。尾蚴在此腺体分泌物保护下渡过其在外界生存的时间。尾蚴的4对小单细胞腺主要包含中性糖蛋白及结合氨基的蛋白质(可能是含酶物质),此腺体物质可能是在尾蚴进入昆虫宿主(草螽)体内穿钻其胃壁进入血腔时分泌出能溶解胃壁组织帮助尾蚴的穿钻行为。成熟后蚴的穿刺腺对PAS反应呈强阳性,其分泌物可以溶解囊蚴的囊壁,使后蚴迅速脱囊。各幼虫期其他器官组织的组化成分也经观察。     

Diversity and morphology of abdominal glands in workers of the ant genus Myopias (Formicidae,Ponerinae)

Histological examination of serial sections through the abdomen of workers of three species of Myopias ants revealed the presence of several exocrine glands. These include the common venom and Dufour glands as well as the pygidial gland, but also more specific sternal glands and glands associated with the sting base and the gonostyli. Two of these glands have not been reported previously among ants: one is the paired oblong plate gland, that occurs next to the oblong plate and may have a pheromonal function. The other novel gland is the paired sting shaft gland, that occurs at the dorsal side in the proximal region of the sting shaft. A remarkable characteristic of these Myopias ants is that all glands of class-3 show ducts with gradually widening internal diameter. Myopias emeryi shows a clearly more simple variety of abdominal glands than Myopias maligna and M. sp.1.