Micropylar Plate Research Articles

Comparative morphology of the eggs from the eight species in the genus Agathemera Stål (Insecta: Phasmatodea), through phylogeneticcomparative method approach.

Morphology of Phasmatodea eggs is remarkably diverse and highly valuable in taxonomic research. Two alterative hypotheses have been proposed to describe the phylogenetic relationship of the species from the genus Agathemera Stål. Additionally, descriptions of the egg morphology within Agathemera have been done based on the eggs of two species. This small sample size does not represent the diverse egg morphology along the genus, thus we attempt to describe the eggs from all the known Agathemera species. The main goal of the present study is to determine whether the evolution of the eggs occurred through either divergent or convergent evolution. We based our descriptions on morphometrics, morphology and the ultrastructure. For data analysis, principal component analysis (PCA) was performed on morphometric variables and the characters emerged from the morphological and ultrastructure were mapped over the molecular phylogeny. The results show that it is possible to discriminate among species using the morphology of the different egg structures, and furthermore, a divergent event at the base of the tree, differentiate the overall egg shape and the internal micropylar plate shape. Finally, we conclude that both divergent and convergent evolution are shaping the different structures of the Agathemera eggs.

Revision of the Oriental subfamily Heteropteryginae Kirby, 1896, with a re-arrangement of the family Heteropterygidae and the descriptions of five new species of Haaniella Kirby, 1904.(Phasmatodea: Areolatae: Heteropterygidae).

Revision of the Oriental subfamily Heteropteryginae Kirby, 1896, with a re-arrangement of the family Heteropterygidae and the descriptions of five new species of Haaniella Kirby, 1904.(Phasmatodea: Areolatae: Heteropterygidae).

Studies on Neotropical Phasmatodea XVI: Revision of Haplopodini Günther, 1953 (rev. stat.), with notes on the subfamily Cladomorphinae Bradley & Galil, 1977 and the descriptions of a new tribe, four new genera and nine new species(Phasmatodea: "Anareolatae": Phasmatidae: Cladomorphinae).

Studies on Neotropical Phasmatodea XVI: Revision of Haplopodini Günther, 1953 (rev. stat.), with notes on the subfamily Cladomorphinae Bradley & Galil, 1977 and the descriptions of a new tribe, four new genera and nine new species(Phasmatodea: "Anareolatae": Phasmatidae: Cladomorphinae).

EGG CAPSULE MORPHOLOGY OF THE STICK INSECT BURRIA LONGIXIPHA BRUNNER (PHASMATODEA HETERONEMIIDAE) FROM SOMALILAND

SUMMARY The egg of the ramuline Burria longixipha Brunner (Phasmatodea Heteronemiidae) has been observed under the SEM and the general and fine chorionic features of ootaxonomic relevance are described. Size, shape, opercular and capsule patterns have been reported; structural details of the edge of the broken exochorion have also been given. The negative angle of the operculum (lacking a capitulum), the presence of an air-penetrated layer on the micropylar plate and the constitution of the micropylar cup together with the elegant network of fibres on the capsule and operculum appear to be the distinguishing features of B. longixipha. Comparative morphology of the chorion reveals a neat distinction from the species of the related genus Ramulus [R. affini s Schulthess-Schindler, R. sansibarus (Stai), R. lingulatus (Scali & Capra)] and further strengthens the idea that within the latter, the Ramulus affinis-iike group should be separated from the Ramulus sansibarus-like. group of species. Also, greater simi...

Structural features of eggs of the basal phasmatodean Timema monikensis Vickery & Sandoval, 1998 (Insecta: Phasmatodea: Timematidae)

Structural features of the eggs of a basal phasmatodean, Timema monikensis Vickery & Sandoval, 1998 (Timematidae) were examined. The eggs of this species are soft and deposited coated with soil and/or other extraneous particles. The chorion, which is transparent and weakly sclerotized, is composed of an endochorion and an exochorion. The non-inclined operculum is located at the anterior pole of the egg. The chorion in the marginal region of the operculum is thinned to form an opercular collar together with the chorion of the egg body. An inverted triangular micropylar plate is on the ventral side of the egg attached to the opercular collar. The micropylar plate is without external differentiations but is specialized inside the chorion. A single micropyle, with a simple funnel-shaped chorionic opening, occurs on either side of the micropylar plate. The posterior mound, located at the posterior pole, is a thickened chorion rich in fine vertical striations, and the serosal cuticle beneath is thickened and highly specialized. The eggs of Timematidae were characterized and compared with those of Euphasmatodea and Embioptera. A phylogenetic discussion is presented, strongly supporting the assemblage of Timematodea, Euphasmatodea and Embioptera as monophyletic.

Uma nova espécie de Cladomorphus Gray, 1835 (Phasmatidae, Cladomorphinae) de Minas Gerais, Brasil

Cladomorphus trimariensis sp. nov. é descrita de Três Marias, Minas Gerais. A nova espécie difere de C. phyllinus Gray, 1835 principalmente pelo opérculo e placa micropilar do ovo, ausência de espinhos nas pernas médias e posteriores e pelas projeções distais nos tergos IV e V, que são menos desenvolvidas.

Revision of Oriental Phasmatodea: The tribe PharnaciiniGünther, 1953, including the description of the world's longestinsect, and a survey of the family Phasmatidae Gray, 1835 withkeys to the subfamilies and tribes(Phasmatodea: "Anareolatae": Phasmatidae)

Revision of Oriental Phasmatodea: The tribe PharnaciiniGünther, 1953, including the description of the world's longestinsect, and a survey of the family Phasmatidae Gray, 1835 withkeys to the subfamilies and tribes(Phasmatodea: "Anareolatae": Phasmatidae)

Structure of the Specialised and Unspecialised Chorion of the Egg in the Stick Insect Malacomorpha cyllarum (Phasmatodea)

The chorion of deposited eggs of the bisexual phasmid Malacomorpha cyllarum (Westwood 1859) was examined by LM, SEM and TEM. The unspecialised chorion consists of three principal layers, from which especially the second one is heavily mineralised. Distinction of sublayers is possible mainly by their different electron density, spongy appearance, and mineralization or simply by phase interfaces, but appears rather arbitrarily in most cases. Specialised regions of the chorion are the operculum and the micropylar plate. The operculum largely shows the same series of layers, but is generally thicker as the unspecialised chorion. Stratification of the highly modified microplyar plate is more complex and characterised by additional spongy modifications, which appear to be derived from the innermost third principal layer. Two micropylar canals, collapsed distally and proximally, run through the micropylar strand. These canals neither open to the exterior nor to the interior of the egg. External and internal closure are achieved by chorion material rather than a secretory plug.

Light and sem studies on the life stages of illeis indica (TIMB.) and its predatism on phyllactinia corylea (PERS.) karst. infecting mulberry

The fungivonis insect Illeis indica is a potential biocontrol agent of Phyllactinia corylea which causes powdery mildew in mulberry. The present study by light and scanning electron microscopy explains the life stages of I. indica and its feeding behaviour on P. corylea borne on infected mulberry leaves. The eggs are laid in clusters of 5–23 on the abaxial surface of infected leaves. Each egg has 16–18 aeropyles circularly arranged at its distal end around a micropylar plate. Total larval period of I. indica is about 15.60 days with four instars and its life cycle is completed in 38.50 days. The grubs feed only on conidia during first instar, on conidia and conidiophores during second instar, and also on parts of mycelia during third instar. The final instar grubs feed on entire aerial mycelial mass leaving only stomatopodia and hyphal remnants attached to them. Pupation is for 6–7 days and the pupae remain motionless and attached to the abaxial leaf surface. Adults also feed voraciously on the fungal mass and the fertilized females lay eggs after about 7.03 ±0.144 days. The grubs and adults clear off the fungal mass from the infected leaves without leaving any mycelial patch and the fungus does not regenerate on such cleared leaves. Field observations indicated a drastic fall in the incidence of powdery mildew disease in mulberry even in the usual peak disease period, with the increased population of I. indica in the mulberry garden.

The micropylar plate of the eggs of Phasmida, with a survey of the range of plate form within the order

Eggs of Phasmida are characterized by the presence of a micropylar plate system. The nature of this plate is discussed and the relevance of differences in plate structure to the taxonomy of the order is considered. A survey is made of the range of plate structure throughout the order, covering the external plate structure of 384 species and the internal plate structure of 179 species in forty of the forty‐four subgroups of the order.

Descriptive terminology of the phasmid egg capsule, with an extended key to the phasmid genera based on egg structure

An attempt is made to standardize further the descriptive terminology of the phasmid egg capsule by introducing stricter definitions and standard abbreviations. In addition, the various forms of the internal micropylar plate are categorized. Eophasma Sellick is replaced by Eophasmodes nov.n. A key to 131 generic forms of these eggs is provided. Where more than one egg form is associated with a genus, a diagnosis of the subgroups is provided.

The range of egg capsule morphology within the phasmatodea and its relevance to the taxonomy of the order

Within the order Phasmatodea there is a basic egg capsule morphology which defines the order. This shows extensive variation in detailed form. Some of this is aberration, which can be recognised and excluded from taxonomic considerations. Much is adaptation to egg‐laying techniques and egg survival. Nevertheless the range of egg capsule form both externally and internally is a valuable aid to the classification at sub‐ordinal level and below of this group of insects. In particular this confirms the Timematodea as members of the order, confirms the distinct status of Phylliidae and shows some so far undivided groups such as Necrosciidae to be taxonomically very diverse. A new tribe Extatosomatini is proposed for Extatosoma Gray on the basis of both egg and adult morphology. A survey of internal micropylar plate types within the order is given.

Egg chorion architecture in stick insects (Phasmatodea)

Comparative analysis of egg chorion architecture by scanning and transmission electron microscopy is reported in about 50 species of stick insects (Phasmatodea). Particular attention has been paid to: (1) synthesis and structure of egg shell layers; (2) egg shape; (3) morphology of the external chorionic surface; (4) position and structure of the micropylar plate and its cup; (5) morphology and details of the operculum, including capitulum or pseudocapitulum; and (6) posterior pole differentiation (the so-called polar mound), The taxonomic value of the various characters is discussed: some are clearly species-specific, while others (such as general egg shape and micropylar plate) appear to reflect phylogenetic relationships of higher rank. Intraspecific features, such as the fine chorionic and opercular patterns of Bacillus and Clonopsis, have been recognized. In natural hybrids, egg chorion architectures were related to that of the parent species, resembling one of the parents in some cases and being intermediate between the 2. The study of the Phasmatodea egg can provide much taxonomic information that is useful in the definition of natural groups.

Morphogenesis of the micropylar apparatus in ovarian follicles of the fungus gnatBradysia tritici (syn.Sciara ocellaris).

The ultrastructure and morphogenesis of the micropylar apparatus (MPA) have been studied in follicles of the fungus gnatBradysia tritici. The MPA is formed by a group of follicle cells located at the anterior pole of the single large nurse cell. In principle, the MPA consists of two thickened plates made of vitelline membrane material, the lower (LMP) and upper micropylar plate (UMP). The former is synthesized by 3 follicle cells, the latter by 4 different follicle cells. The micropylar channel system consists of a central channel with a single outer orifice and three branches which reach the plasma membrane of the oocyte. The branches are moulded by cellular extensions of the LMP-forming cells which are sandwiched between the two growing micropylar plates. Microtubuli and microfilaments were identified parallel to the long axis of the cellular extensions. At the time of MPA synthesis the nurse cell is still large and hence the MPA-forming cells have no contact to the oocyte. At the end of oogenesis when the regression of the nurse cell is completed, the MPA becomes connected to the other parts of the egg shell. At this time an ultrastructurally homogeneous region forms in the adjacent ooplasm ("cytoplasmic cone"). The possible relevance of these cytological observations for the control of development is discussed.

Fine structure of the eggshells of four primitive moths: Hepialus hecta (L.), Wiseana umbraculata (Guénée) (Hepialidae), Mnesarchaea fusilella walker and M. Acuta philp. (Mnesarchaeidae) (Lepidoptera, Exoporia)

The eggshells of Hepialus hecta, Wiseana umbraculata (Hepialidae) and of Mnesarchaea fusilella (Mnesarchaeidae) (Lepidoptera, Exoporia) were studied by scanning electron microscopy (SEM) and transmission (TEM) electron microscopy. All 3 species show a very similar surface sculpture of the micropylar region which, however, is very different from the eggs of the Ditrysia. The micropylar plate is large and oval. There are only 2 or 3 micropylar openings. In the hepialid moths, the surface of the egg's main body is characterized by spherical protuberances. The radial fine structure of the eggshells of all 3 species as well as of alcohol-stored eggs of Mnesarchaea acuta (Mnesarchaeidae) is basically identical to the eggshell of Korscheltellus lupulinus (Hepialidae). The chorion consists of only one layer, which, in the hepialid species, shows a crystalline-like fine structure. The vitelline envelope is composed of a thin, laminated, outer layer (V-2) and a thick, rigid, inner layer (V-1) that is traversed by large numbers of canals. This kind of eggshell architecture is distinctively different from that of the ditrysian Lepidoptera.

THE EGGS OF STICK INSECTS,SIPYLOIDEA SIPYLUS(WESTWOOD) ANDORXINES MACKLOTTIDE HAAN (PHASMATODEA, HETERONEMIIDAE): A SCANNING ELECTRON MICROSCOPIC STUDY

Scanning electron microscopy, which has proven of great value for ootaxonomy in many insect orders has already been used to study Phasmatodea. We report here the description of the eggs of two Necrosciinae species, the amphigon, O. macklotti and the obligatory parthenogen, S. sipylus. In the latter, chorion sculpturing is characterized by a net of ridges covered by rows of conical processes and hairy spines which define irregular polygonal areas covered by short conical reliefs of varying heights. Such sculpturing is also found on the operculum. The chorionic pattern is common to the entire egg capsule in O. macklotti. An irregular net of 5 prominent ridges defines uneven areas covered by low mamelons. Evenly distributed spiny processes are found on ridges as well as in the intervening areas. Several features characterize the two species, but in both, the micropylar plate is lance-shaped, the micropylar cup is protected by a projecting blade, and the three-layered exochorion shows a spongy-columnar stratu...

Ultrastructure and amino acid analysis of the eggs of the stick insects, Lonchodes pterodactylus gray and Carausius morosus br. (Phasmatodea: heteronemiidae)

The scanning electron microscope morphology and the amino acid composition of the egg capsules of two Lonchodini, Lonchodes pterodactylus and Carausius morosus, are reported. In both species, the egg shows a structural organization common to all Phasmatodea so far investigated. Many details appear to be similar in the two species, such as the egg capsule tubercular sculpturing, the general features of the micropylar plate, and the presence of a well-developed opercular capitulum. These common characteristics fully support the inclusion of these two species within the same tribe. However, differences in the opercular sculpturing patterns, capitulum shape and implantation, micropylar cup conformation, the presence of tubercule-less pits on the egg capsule, and the polar mound in L. pterodactylus, indicate not only specific differences, but also at the generic level. Egg chorion characteristics therefore appear, to be of high taxonomic value in the Phasmatodea. From our analysis, it appears that the frequent anomalies of the micropylar plate in C. morosus are not directly related to the internal abdominal pressure in the female, as formerly suggested, but rather to ovariolar disturbances due to intersexuality. The chemical information obtained from amino acid analysis of the egg shell of the two species has confirmed a high glycine content, a stable quantity of serine, and trace amounts of cystine and methionine, and also showed a marked difference in tyrosine, when compared with the bacilline, Clonopsis gallica. The amino acid composition of the stick insect egg shell suggests that its proteins resemble silk proteins. Thus, the egg morphology at scanning electron microscope level and the amino acid composition data contribute to both ootaxonomy and better understanding of the phylogeny of the order.

Fine morphology and amino acid analysis of the egg capsule of the stick insect, Clonopsis Gallica (Charp.) (Cheleutoptera: Bacillinae)

The scanning electron microscope morphology and the amino acid composition of the egg capsule of the stick insect Clonopsis gallica have been studied. The egg capsule shows an irregular but characteristic pattern of rounded tubercules, which at higher magnifications reveal a still more detailed sculpturing. The micropylar plate shows specific structural characters, including a shallow square micropylar cup without micropylar orifices; ovariolar eggs, however, show a number (from 3 to 5) of wide, open micropyles. The opeculum does not possess the capitulum nor the pseudocapitulum, but among the prominent tubercules of the central area some aeropyles are present. The thick 3-layered chorion has a uniformly smooth internal surface; the spongy submicropylar plate possesses a tubule connecting the chorion to the vitelline membrane. The amino acid composition has revealed that glycine is the most common residue (33%), followed by serine and alanine (about 10% each), with traces of cystine and methionine. SEM features specifically identify the egg of C. gallica but also reveal some genuine similarities with the egg of B. rossius. The meaning of the existence of the micropylar orifices during egg development has been discussed. The amino acid composition is a new datum for the Cheleutoptera and it has been compared with that of insects having an orthopteroid structure. In particular, the high glycine content in C. gallica egg shell suggests a certain resemblance with the species of 5 families of Tettigonioidea, whilst there are definite differences with species of Gryllidae and Acrididae. Thus, the egg morphology and amino acid composition data can be utilized as aids in understanding the phylogeny and egg physiology in several insect orders.