Aero-micropylar Processes Research Articles

Stenozygum coloratum (Klug, 1845) (Heteroptera: Pentatomidae)’un Spermateka ve Yumurta Morfolojisi

The spermathecae and egg morphology of Stenozygum coloratum (Klug, 1845) were examined with light and scanning electron microscopy, and their external morphology was characterized in detail (egg chorion surface, operculum, and aero-micropylar processes, and spermatheca morphology). Eggs barrel-shaped; operculum round and the hatching line can be easily distinguished in the scanning electron photograph. The egg batches usually consist of 12 eggs. Because of the thick egg chorion, embrionic development was not visible from the outside. The eggs of S. coloratum are usually laid in two rows and are glued to the Capparis spinosa (Capparacea) plants. The egg burster is highly sclerotized, thick and T shaped. It is clearly observed in the hatched egg. Egg-burster is remains attached with the inside lateral surface of the egg. The well-marked operculum intersects the ring of 18–20 short pipe shaped micropylar projections that are found between the tubercles around the hatching line. In S. coloratum, the spermathecae has a semi-oblong spermathecal bulb. The spermathecal duct, pumping region, dilation of spermathecal duct and distal and proximal ducts. The pumping region has distal and proximal flanges. The balloon-like median spermathecal dilation has sclerotized rod and is narrowed distally and tipped. The proximal area of the spermathecal duct is close to the vagina opening. Two V-shaped sclerites and two ring sclerites are localized on the genital chamber (vagina) wall in to which opens the spermathecae. Egg and spermathecae structures in insects differ from species to species. In this study, spermathecae and egg structures of this species, which have not been studied before, were examined in detail, and it was aimed to contribute to systematic and taxonomic studies.

The eggs and nymphs of predatory stink bugs (Hemiptera: Pentatomidae: Asopinae): what do we know?

The Asopinae are known for their predatory behavior, differing from the phytophagous habits of most pentatomoids, feeding mostly on soft body insects such as larvae of Lepidoptera and Coleoptera. For this reason, asopines have been studied as biological controllers in integrated pest management programs. Notwithstanding their clear relevance, the general knowledge about Asopinae has important gaps, especially regarding immature. Thus, the importance of studying eggs and nymphs of true bugs (Heteroptera) is evident, contributing to understand their classification, biology, and evolution. In this perspective, we conducted a research about immature of predatory stink bugs, highlighting critical features for identification. We present: (1) a literature overview about eggs and nymphs of predatory stink bugs guided by selected categories; (2) images of females laying eggs of ten species and nymphs of thirty-four species, obtained on websites with a citizen science approach; (3) a comparative morphology of immature of six species reared under laboratory conditions, which we examined using light and scanning electron microscopy. We found a remarkable morphological diversity of both eggs and nymphs of Asopinae, revealing key features to establish diagnoses for identification and potential characters to phylogenetics, such as the aero-micropylar processes and chorion scultpturing of the eggs; and the coloration, labium and abdominal plates morphology of nymphs. The results show that little is known about Asopinae immature considering the diversity of the group; however, information obtained by citizen science initiatives, for instance, can improve this knowledge.

Morphology of Immature Stages, Chromatic Polymorphism of Adults and Natural History of Oplomus catena (Heteroptera: Pentatomidae: Asopinae).

The predatory stink bugs are well known by their behavior, but the knowledge of the immature morphology and their natural history are scarce. Studies on predatory stink bugs are important to better understand their evolution and their use as biological controllers. Here, we describe the morphology of egg and the five nymphal instars of Oplomus catena (Drury, 1782), using optical and scanning electron microscopy. In general, O. catena immatures are very distinctive from other Asopinae species already studied. The egg is black, with short aero-micropylar processes and similar to those described for Stiretrus species. The nymphs can be diagnosed by the abdominal plates very large and bright blue. The color polymorphism of adults is fully illustrated, and four color patterns are proposed. The natural history of the species is described based on field and laboratory observations. The known prey of the species is reviewed and new preys are reported. The morphological and biological traits here described are discussed in order to better understand the biological role of predatory stink bugs.

External morphology of immature of Tynacantha marginata Dallas, 1851 (Hemiptera, Heteroptera, Pentatomidae).

Immature stages of Neotropical Asopinae have been poorly studied. Here, the external morphology of eggs and nymphs of Tynacantha marginata Dallas are described using light and scanning electron microscopy. The egg is barrel-shaped with smooth surface, and long aero-micropylar processes. In the first instar, the color of abdomen varies along the development from yellow to red, the dorsal plates are pale, and the surface of evaporatorium bears spiked projections. From the second, the evaporatorium surface is reticulated. From third instar, the pronotum is orange with black lateral margins. The eggs and nymphs of T. marginata are unique among Neotropical Asopinae species of which the morphology is known, allowing the early identification of the species.

Comparative Morphology of Eggs of the Predators Brontocoris tabidus and Supputius cincticeps (Heteroptera: Pentatomidae)

Abstract Brontocoris tabidus (Signoret)and Supputius cincticeps (Stal) (Heteroptera: Pentatomidae) are natural enemies of lepidopteran defoliator pests. Therefore, more detailed information regarding the morphology of their eggs will certainly enhance the identification of these predators during the initial developmental stages for easy recognition of their presence in the field. In this study, eggshell morphology and morphometry of B. tabidus and S.cincticeps were examined. The diameter of the B. tabidus eggs was 2.03 ± 0.12 mm, height of 2.86 ± 0.08 mm, and the number of aero-micropylar processes were 14.8 ± 0.74; for eggs of the S.cincticeps, the diameter was 1.80 ± 0.32 mm, height 2.05 ± 0.27, and aero-micropylar processes 12.6 ± 1.18 mm. The eggs are oval to subglobose in shape, narrowing from the base to the apex; the operculum is circular convex with a circular array of aero-micropylar process on the anterior pole of the egg. The spicules seen on the flattened side of the B. tabidus and S.cincticeps eggs are fewer than those found in the operculum. Egg height and the number of aero-micropylar processes were higher in B. tabidus than in S.cincticeps. Such distinctive characters enable the identification of these predator's eggs.

External egg structure of the Pentatomidae (Hemiptera: Heteroptera) and the search for characters with phylogenetic importance.

The chorionic structure of sixteen pentatomid species is described. Morphological patterns in different taxonomic levels are discussed. In addition, egg characters useful in cladistic analyses are listed, and some of those characters are tested for congruence with two cladistic analyses previously conducted within Pentatomidae. Descriptive studies were conducted with Banasa induta, Capivaccius bufo, Catulona pensa, Chinavia armigera, Chinavia aseada, Chinavia brasicola, Chinavia runaspis, Dichelops furcatus, Euschistus heros, Euschistus riograndensis, Euschistus paranticus, Mormidea cornicollis, Podisus distinctus, Podisus nigrispinus, Serdia apicicornis, and Thoreyella maracaja. The eggs were examined and photographed under light and scanning electron microscopy. Based on literature data, a list of 40 egg characters with potential phylogenetic importance has been compiled. Some of these characters were included in the cladistic analyses of the genus Nezara (six characters) and of the Chinavia obstinata group (five characters). Both analyses were performed in TNT with equal weighting of characters. The eggs of most of the Neotropical species studied were barrel-shaped, chorion translucent and spinose, with aero-micropylar processes that were short and clubbed. The patterns of egg morphology could be identified in Carpocorini, Procleticini, and in the genera Banasa, Chinavia, Euschistus, Mormidea, and Podisus. In the cladistic analyses, the inclusion of egg characters did not affect the topology of the trees shown in the original papers. For the analyses, the egg characters were somewhat informative. At present, a total of 286 Pentatomidae species have their egg stage described.

Morphology and Postdepositional Dynamics of Eggs of the Predator Podisus distinctus (Stål) (Heteroptera: Pentatomidae: Asopinae).

The predator Podisus distinctus (Stål) (Heteroptera: Pentatomidae: Asopinae) has been reared to control lepidopteran defoliators. In this study, we describe this predator's morphology, postdepositional dynamics and eggs in different developmental stages under scanning electron microscope. Its eggs are subglobular and ovoid, narrower at the base than at the top, with a convex, circular operculum. They measure 1.09±0.03 mm in height and 0.90±0.04 mm in diameter. The aero-micropylar processes number 16.00±2.00 and are arranged radially at the egg anterior pole. Immediately after laying, the egg color is pearl-like, and soon after turns gray. Orientation of the spine-like projections and aero-micropylar processes also change after deposition. Though the eggs of P. distinctus are similar to those of other species of the genus Podisus, certain aspects, including the egg size and shape, chorion micro-sculptures, and number of aero-micropylar processes, are specific, allowing for differentiation from other related species.

Morphology of Immatures of Caonabo pseudoscylax (Bergroth) (Hemiptera: Pentatomidae)

Characters of immatures are potentially useful in identifying taxa, but few immatures of Pentatomidae were described. The objectives here are to describe the egg and five nymphal instars of Caonabo pseudoscylax (Bergroth) under light and scanning electron microscopy. Adults, eggs, and nymphs were collected on Homolepsis glutinosa during 2008, in Criciúma (Santa Catarina, Brazil). The egg of C. pseudoscylax is subcylindrical, chorion reddish brown, slightly translucent, and with granulate surface. Aero-micropylar processes translucent, spongy, and strongly clavate. Nymphs without punctures, spiracles placed near the lateral abdominal margin. The dorsal abdominal gland has rounded ostioles bearing cuticular valve; spout peritreme smooth, directed anteriorly; evaporatorium network-shaped; and microsculpture poorly ornamented. Humeral angles of the pronotum were produced from fourth instar. The almost marginal placement of abdominal spiracles may diagnose the nymphs of C. pseudoscylax from first instar to adulthood.

Description of the immature stages of Glyphepomis spinosa Campos & Grazia (Hemiptera: Pentatomidae: Pentatominae: Carpocorini)

The study of immature stages is important in phylogeny, as well to the recognition and control of pest species. Glyphe-pomis Berg is included in the tribe Carpocorini. This paper describes the morphology of eggs and nymphs of Glyphepomis spinosa Campos & Grazia. Adult specimens were collected on rice plants in Formoso do Araguaia, Tocantins, Brazil, and they were reared in the laboratory. The immatures obtained were analyzed with a light stereomicroscope and scanning electron microscope. Eggs and nymphs were measured and illustrated and/or photographed. Eggs are barrel-shaped, light green; operculum round and convex; chorion translucent, bright and granulated; aero-micropylar processes clubbed, 68 on average. All instars have oval body and obtuse tylus, surpassing jugae. In the 1st instar, head, thorax and abdominal plates are black, and abdomen is reddish brown; punctures are absent. From 2nd instar on, head and thorax are grayish with dark punctures, and the abdomen is whitish with dark-red punctures. In relation to other Carpocorini species that occur on rice, the eggs of G. spinosa resemble those of Oebalus poecilus (Dallas), a major rice pest in South America. However, nymphs of both species can be easily differentiated by their general color: in O. poecilus all instars have a dark head and thorax and red abdomen.

Morphology of spermatheca and eggs of Coptosoma putoni Montandon, 1898 (Hemiptera: Plataspidae)

Bu calismada Coptosoma putoni Month. (Hemiptera: Pentatomidae)’ nin yumurta ve spermatekasi isik ve taramali elektron mikroskobuyla (SEM) incelenmistir. Coptosoma putoni yumurtalari genellikle basak seklinde ve iki sira halinde birakilmaktadir. Bir yumurta kumesinde 12-16 arasinda yumurta bulunmaktadir. Yumurtalarin uzunlugu ortalama 0.81 mm, genisligi ise 0.48 mm.dir. Yumurtalarin her iki yan yuzeyi hafif iceri cokuktur. Yumurta yuzeyi koryonik cikintililarla kaplidir. Mikropiller operkulum cevresine dairesel olarak dizilmistir ve sayilari 26-29 arasinda degismektedir. C. putoni de spermateka siferikal spermatekal rezervuar, pompalama bolgesi, pompalama flangeleri, spermatekal kanal, bir genital oda ve skleritler ile karakterize edimektedir

External morphology of the egg and the first and fifth instars of Cyrtocoris egeris Packauskas & Schaefer (Hemiptera: Heteroptera: Pentatomidae: Cyrto-corinae)

Cyrtocorinae is an uncommon, small, and exclusively Neotropical group in Pentatomidae, whose immatures are poorly understood. In this paper, the egg and first and fifth instars of Cyrtocoris egeris Packauskas & Schaefer are studied with the scanning electron microscopy (SEM). Specimens were collected in Maquiné, Rio Grande do Sul, Brazil. Immatures were analyzed with light stereomicroscope and SEM. The egg’s chorion surface is predominantly smooth alternated with granulated areas, and an average of 54 clubbed aero-micropylar processes are arranged in three irregular rows. In the first and fifth instars, organization of the external dorso-abdominal scent efferent system suggests an analogy to the metathoracic external scent efferent system of the adult, because of structures similar to the evaporatorium, evaporatory channel, and auricle peritreme; the last structure is absent in the first instar. Abdominal sterna III–VII have 1+1 (first instar) and 2+2 trichobothria (fifth instar). Ultrastructural observations allowed recognition of unique characters at the egg stage and conserved features at the nymphal stage in C. egeris.

Description of spermatheca and eggs of Eurygaster austriaca (Schrank, 1778) (Heteroptera: Scutelleridae),based on optical and scanning electron microscopy

Spermatheca and egg morphology of Eurygaster austriaca (Schrank, 1778) were studied by optical and scanning electron microscopy (SEM). The spermatheca of E. austriaca is characterized by a spermathecal bulb, a pumping region, distal and proximal flanges and ducts, and a genital chamber. Each female was shown to deposit 14 green eggs on average in mass. The spherical eggs averaged 1.05 ± 0.05 mm in diameter. The first external evidence of embryonic development was the appearance of 2 red eye spots opposite each other beneath operculum followed by the appearance of a blackish T-shaped egg-burster between the eye spots. The thickened highly sclerotized egg-burster has sucker-shaped structures on the both sides of the tail. Egg surfaces are covered with clearly marked polygon patterns with tubercles. There were 17-19 aero-micropylar processes shaped like truncated cones scattered among the polygons.

Morphological features of the eggs of Pentatomidae (Hemiptera: Heteroptera)

Eggs of 14 species within two subfamilies (Edessinae and Pentatominae, tribes Carpocorini, Nezarini, Pentatomini, Procleticini, and one unplaced species) of neotropical pentatomids were studied with scanning electron microscopy, and their external morphology was characterized in detail (chorion surface, operculum, and aero-micropylar processes). Eggs of these species have similar characteristics to those already described for other pentatomids. Most of them are barrelshaped, except in Edessa meditabunda (with spherical eggs) and Odmalea basalis (whose eggs have flattened lateral faces). A “T”-shaped ruptor ovis is present in all studied species; eclosion line at the operculum rim may be visible or not. Average size of eggs (length x width) ranges from 0.9 ± 0.12 x 0.9 ± 0.05 mm (Euschistus picticornis) to 2.1 ± 0.12 x 1.7 ± 0.10 mm (Chinavia erythrocnemis); the number of the aero-micropylar processes ranges from 10 (C. musiva) to 86 (C. obstinata). Chorion surface has a variable aspect: eggs of Euschistus spp., Loxa deducta, and Pallantia macunaima have the spinose chorion type; C. erythrocnemis, C. longicorialis, C. obstinata, C. pengue, and Grazia tincta have a reticulate chorion; C. musiva, O. basalis, and E. meditabunda have a granulated chorion; and Thyanta humilis has a salebrose chorion type. All the species with described eggs in the Edessinae share the same diagnostic features. In Pentatominae, we did not identify shared characters among the species at subfamily or tribe level. Chorion sculpture pattern and aero-micropylar processes shape, as well as number, are diagnostic features at genus level; however, a few species could be identified in the egg stage.

Morphology of eggs and spermatheca of Odontotarsus purpureolineatus (Heteroptera, Scutelleridae)

The morphology of the spermatheca and eggs of Odontotarsus purpureolineatus were studied by optical microscopy and scanning electron microscopy. The spherical eggs were about 1.35 mm long and 1.09 mm wide. The egg batches generally consist of 13–14 eggs. The egg surface is covered by polygonal (hexagonal and pentagonal shapes prevail) ridges and tiny chorionic tubercles. There were 8–10 aero-micropylar processes between the polygons. The spermatheca of O. purpureolineatus is characterized by a spherical spermathecal bulb, a pumping region, a flange of pump and dilation of spermathecal duct. Spermathecal processes and a median spermathecal dilation with sclerotized rod are missing. The spermathecal bulb and the pumping region possess many pores.

Descrição dos estágios imaturos e biologia de Chinavia pengue (Rolston) (Hemiptera, Pentatomidae)

Adultos de Chinavia pengue (Rolston, 1983) foram coletados em Garopaba, SC, e criados em laboratório sob condições controladas (24 ± 1°C; UR 70 ± 10%; 12hL:12hE). Como alimento, adultos e ninfas receberam vagens verdes de feijão (Phaseolus vulgaris L.). Os ovos de C. pengue seguem o padrão de coloração e esculturação do cório e coloração e forma dos processos aero-micropilares descrito para as espécies neotropicais de Chinavia. Ninfas de 1º instar possuem uma mancha ovalada no dorso da cabeça e tórax, característica das espécies de Chinavia. Em C. pengue, essa mancha tem coloração laranja-avermelhada, e as manchas abdominais (4+4 manchas laterais e uma mediana) são brancas. Características exclusivas das ninfas de 2º a 5º ínstares de C. pengue são a coloração laranja-avermelhada das manchas do pro- e mesotórax e das manchas circulares no centro das placas abdominais laterais. Não se observou sobreposição nas medidas da largura da cabeça entre os cinco ínstares. Cada fêmea depositou 15,9 ± 4,18 posturas e 218,8 ± 48,60 ovos, sendo 14 ovos/postura o arranjo mais freqüente. A fertilidade foi de 70,0% ± 19,01; a mortalidade no 2º ao 5º estádio foi de 1,6% ± 4,49. A razão sexual obtida foi de 1 macho: 1 fêmea. A duração da fase imatura (ovo a adulto) foi de 45,7 ± 2,99 dias.

Descrição dos estágios imaturos de Chinavia erythrocnemis (Berg) (Hemiptera: Pentatomidae)

Adults and nymphs of Chinavia erythrocnemis (Berg) were colected on Sebastiania commersoniana (Baill.) Smith & Downs in the Parque Estadual do Espinilho in Barra do Quarai county, RS, and used to establish a laboratory culture reared on green pods of Phaseolus vulgaris L. Egg coloration is light-brown, chorion is reticulated and aero-micropylar processes are clubbed and white; mean number of aero-micropylar processes is 61. Eggs are very similar to those from other Neotropical Chinavia species, but the average number of 12 eggs/mass is unique among Chinavia species. Nymphs are predominantly black, with the distal part of the head, femur, and the basal part of tibia, red. First instar has the dorsal maculae of the head and thorax in red coloration, and the abdomen with a series of 3+3 dorsal white maculae. Second to fifth instars have 1+1 white maculae on lateral margins of pronotum and 2+2 white maculae on abdome. Fourth and fifth instars show an ovate white maculae in the middle of lateral plates of abdomen. Nymph coloration and the size, number and position of the maculae on pronotum and abdomen are diagnostic to C. erythrocnemis.

Optical illusions in scanning electron micrographs: the case of the eggshell of Acrosternum ( Chinavia) marginatum (Hemiptera: Pentatomidae)

Scanning electron microscopy revealed that—as is common in this family of the Hemiptera—the eggs of the green stink bug Acrosternum ( Chinavia) marginatum are roughly barrel-shaped and possess at their apical pole a row of slender extensions, the aero-micropylar processes. The outer surface of the eggshell carries hexagonally arranged pits. The analysis of cross-fractured eggshells showed that the pits have slender basal extensions with transverse diaphragms. When scanning electron micrographs of the egg surface of A. marginatum are viewed upside down, the perception flips and the pits appear as elevations to all observers addressed. Thus, we are dealing with an optical illusion, which is known as the ‘shape-from-shading effect’. The perceived dents remain robust to changes in the angle of recording (zero to ca. 60° tilt), the magnification (ca. ×100 to ×1400), and the number of pits included in the micrograph (one to several hundred). When through appropriate positioning of the specimen under the electron beam, contrast is significantly reduced and the distinct shadows at the slope of the pits are eliminated, the optical illusion does not appear. It is inferred that shades provide the decisive clue that determines whether bumps or dents will be perceived. Owing to the low resolution of their compound eyes, the shape-from-shading effect on the eggshell of the bug is in all likelihood not perceived by insects.

Egg Shell Architecture of the Stink Bug, Eocanthecona furcellata (Wolff.): Ultrastructure of Micropylar Processes and Egg Burster

Scanning electron microscopic examination of the egg shell and associated structures of Eocanthecona furcellata (Wolff.) (Hemiptera: Pentatomidae) reveals a distinct pattern of structural elements, viz. microsculpture of the chorion, pseudoperculum, egg burster and aeromicropylar processes. The egg shell has a highly decorated chorion with a structural difference at both the anterior and posterior ends. A reticulate type of microsculpture with varying sizes of spine-like projections measures 4.02 ± 0.06 to 8.12 ± 0.05 μm and forms an asteroid-like shape at the anterior pole, while the surface at the posterior end has elongated striations over the chorion measuring 72.00 ± 0.074 μm. The pseudoperculum of the egg shell is a circular lid measuring 518 ± 11.43 μm in diameter. During hatching the line of rupture follows the micropylar ring, and this sometimes extends beyond the ring of micropylar processes. An inverted T-shaped black egg burster measures 202 ± 4.63 μm in length, is well developed and can be seen prior to hatching within a thin and transparent egg shell. It is a median sclerotised part of embryonic cuticle. The aeromicropylar processes are situated at the anterior pole of the barrel-shaped eggs. There are 26–28 aeromicropylar processes arranged in a circle at almost equidistance and each micropylar process is slightly curved opposite to the pseudoperculum lid with a bulbous end at the apex. The aeromicropylar processes are 25.40 ± 0.083 μm in length and 3.02 ± 0.07 μm in width. Each micropylar process has a central canal for the passage of sperm whereas the rest of its body is porous, and allows respiratory interchange.

Egg morphology and hatching in Mormidea pictiventris (Hemiptera: Pentatomidae)

Egg morphology and hatching in the stink bug Mormidea pictiventris (Hemiptera: Pentatomidae) are described with the aid of scanning electron microscopy. In addition, the eggshell is analyzed using transmission electron microscopy and the distribution of follicle cells at the surface of ovarian eggs is studied by epifluorescence microscopy using a DNA-specific fluorescent dye. The surface of the barrel-shaped eggs carries numerous slender processes. Binucleate follicle cells, in most cases arranged in a hexagonal pattern, are responsible for the synthesis of this portion of the eggshell. The rim at the anterior pole of the egg is studded at irregular intervals with short columnar processes, the aero-micropylar processes. Hatching occurs at this pole. The prolarva is wrapped in an embryonic cuticle. Its head portion carries a Y-shaped element, the egg-burster. The major features of the inner face of the eggshell are subtle, radially oriented grooves at the anterior plate and a hexagonal pattern to the surface ornamentation throughout the remainder of the eggshell. Transmission electron microscopy revealed that the processes extending from the surface of the eggshell have a coarse texture, while the eggshell proper is composed of amorphous material. The innermost layer, however, has a trabecular organization. The findings in M. pictiventris are compared with morphological observations on the eggshell in other families of Hemiptera and suggestions are made concerning the meaning of the diverse structures.

Egg morphology and hatching in <i>Mormidea pictiventris</i> (Hemiptera: Pentatomidae)

Egg morphology and hatching in the stink bug Mormidea pictiventris (Hemiptera: Pentatomidae) are described with the aid of scanning electron microscopy. In addition, the eggshell is analyzed using transmission electron microscopy and the distribution of follicle cells at the surface of ovarian eggs is studied by epifluorescence microscopy using a DNA-specific fluorescent dye. The surface of the barrel-shaped eggs carries numerous slender processes. Binucleate follicle cells, in most cases arranged in a hexagonal pattern, are responsible for the synthesis of this portion of the eggshell. The rim at the anterior pole of the egg is studded at irregular intervals with short columnar processes, the aero-micropylar processes. Hatching occurs at this pole. The prolarva is wrapped in an embryonic cuticle. Its head portion carries a Y-shaped element, the egg-burster. The major features of the inner face of the eggshell are subtle, radially oriented grooves at the anterior plate and a hexagonal pattern to the surfa...