The development of the egg of Didymuria cuilescens (Phasmatodea : Phasmatidae : Podacanthinae) - embryology and determination of the stage at which first diapause occurs

1970 ◽  
Vol 18 (2) ◽  
pp. 155 ◽  
Author(s):  
GO Bedford
Keyword(s):  
Instar Nymph ◽  
Posterior Pole ◽  
Anterior Pole ◽  
Warm Temperature ◽  
Continue Development ◽  
First Instar

Development of the egg of D. violescens commences as nuclei multiply and congregate at the posterior pole (stage 1A). A germ disk then forms which elongates and becomes segmented as it turns anticlockwise on the surface of the yolk. Anatrepsis is completed when the tail end of the embryo reaches almost halfway to the anterior pole on the micropylar side of the egg. Katatrepsis commences as the embryo moves head-first around the posterior pole and continues to differentiate. The process is completed when the head of the pharate first-instar nymph comes to rest beneath the operculum at the anterior pole of the egg. Eggs kept at a constant warm temperature enter first diapause when there are numerous nuclei at the posterior pole (stage 1A of embryology), and if held under these conditions for a prolonged period they may emerge from diapause irregularly and continue development. In the field eggs develop continuously but slowly, suggesting that diapause and embryogenesis may proceed together at temperatures favourable to both.

Instability of the anteroposterior axis in spontaneous double abdomen (sda), a genetic variant of Chironomus samoensis (Diptera, Chironomidae)

Development ◽  
1987 ◽  
Vol 101 (3) ◽  
pp. 591-603 ◽  
Author(s):  
K.L. Kuhn ◽  
J. Percy ◽  
M. Laurel ◽  
K. Kalthoff
Keyword(s):  
Genetic Variant ◽  
Laboratory Strain ◽  
Posterior Pole ◽  
Mirror Image ◽  
Anterior Pole ◽  
Spontaneous Formation ◽  
Pole Cells ◽  
Anterior Segments ◽  
Egg Polarity

We have isolated a laboratory strain of Chironomus samoensis in which determination of the anteroposterior egg polarity is disturbed. Most conspicuous is the spontaneous formation of ‘double abdomen’ embryos where head and thorax are replaced by a mirror image of the abdomen. Such double abdomens are found in about half of the egg clusters in this strain, which we call the spontaneous double abdomen (sda) strain as opposed to the normal (N) strain. Also observed in the sda strain, although less frequently, are ‘double cephalon’ embryos showing a mirror-image duplication of cephalic segments in the absence of thorax and abdomen. Moreover, embryos from the sda strain tend to form cells at the anterior pole resembling the pole cells at the posterior pole. Reciprocal crossings between the sda and the N strain indicate that the sda trait is inherited maternally. Spontaneous double abdomen formation is correlated with signs of disturbed egg architecture, including extruded yolk and detached cells. Double cephalons can also be generated by centrifuging embryos from the N strain, whereas centrifugation of sda embryos produces mostly double abdomens. Double abdomen formation can be induced experimentally by anterior u.v. irradiation of embryos from either strain. The sda trait and u.v. irradiation act in a synergistic fashion. The data suggest that the sda trait may be caused by one or more genomic mutations interfering indirectly with the activity of anterior determinants, i.e. cytoplasmic RNP particles necessary for the development of anterior segments. The sda defects may be ascribed to alterations in cytoskeletal components involved in anchoring anterior determinants and segregating them into anterior blastoderm cells.

Morphology of the first instar nymph of Leucaspis loewi Colvée (Hemiptera: Coccinea: Diaspididae)

2012 ◽  
Vol 81 (1) ◽  
pp. 43-47
Author(s):  
Elżbieta Podsiadło ◽  
Anna Mazurkiewicz
Keyword(s):  
Abdominal Segment ◽  
Instar Nymph ◽  
First Instar ◽  
Campaniform Sensillum ◽  
Anterior Spiracle

Morphology of the first instar nymph of Leucaspis loewi Colvée (Hemiptera: Coccinea: Diaspididae) The first instar nymph of Leucaspis loewi Colvée is redescribed and illustrated. The sex has not been determined. It has 5-segmented antennae, one trilocular disc pore associated with the anterior spiracle, one pair of well-developed lobes, and fimbriate plates on all abdominal segments. Tibia and tarsus are not fused - they are separated from each other by a septum. A campaniform sensillum is always present at the bases of the tarsi. Dorsal submedian setae are present on each abdominal segment 1-7.

Anterior Movement of the Crystalline Lens in the Process of Accommodation in Children

2007 ◽  
Vol 17 (4) ◽  
pp. 515-520 ◽  
Author(s):  
B.J. Kaluzny
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Crystalline Lens ◽  
Posterior Pole ◽  
Anterior Pole ◽  
Forward Movement ◽  
Ophthalmic Examination ◽  
Lens Thickness ◽  
Lens Position ◽  
Refractive Status

Purpose To investigate changes of crystalline lens position during accommodation in children with emmetropia, myopia, and hyperopia. Methods A total of 188 children (372 eyes) from 4 to 19 years old (mean age 11.3±4.43) with cycloplegic refractive error within a range +9.00 D to −9.00 D were enrolled. After a general ophthalmic examination, ultrasound biometry was performed, with the eye at a maximal accommodative effort. Cycloplegia was induced by triple installation of 1% tropicamide drops and 30 minutes later the biometric examination was repeated. Results In emmetropic eyes in the process of accommodation, the anterior pole of the crystalline lens moved forward by 0.144±0.14 mm (p ≤ 0.001); the position of the posterior pole did not change. In myopic eyes, the anterior pole moved forward by 0.071±0.13 mm (p≤0.001) and the posterior pole moved backward by 0.039±0.10 mm (p=0.003). In hyperopic eyes, the whole lens translocated anteriorly: anterior pole moved forward by 0.242±0.16 mm (p≤ 0.001) and posterior pole moved forward by 0.036±0.09 mm (p≤0.001). Differences among emmetropia, myopia, and hyperopia were statistically significant. Forward movement of the posterior pole correlated with a low axial length of the eye, and also with plus refractive error and with a smaller accommodative increase of lens thickness. Conclusions In children, accommodative changes of the crystalline lens position depend on refractive status.

scholarly journals Biologi Stenocranus pacificus Kirkaldy (Hemiptera: Delphacidae) pada tanaman jagung (Zea mays L.) di rumah kasa

2020 ◽  
Vol 17 (2) ◽  
pp. 104
Author(s):  
Dosma Ulina Simbolon ◽  
Maryani Cyccu Tobing ◽  
Darma Bakti
Keyword(s):  
Zea Mays ◽  
Life Cycle ◽  
Sex Ratio ◽  
Zea Mays L ◽  
Instar Nymph ◽  
Fourth Instar ◽  
The Third ◽  
First Instar ◽  
Corn Plants ◽  
North Sumatra

<p><em>Stenocranus pacificus </em>Kirkaldy (Hemiptera: Delphacidae) is destructive pest on corn plants in South Lampung and it has been reported to cause corn damages in North Sumatra. The  objective of this research was to study some aspects biology of <em>S. pacificus</em> on corn plants in screenhouse. The research was conducted by observing the biology of <em>S. pacificus</em> that was reared on corn plants in screenhouse.<em> </em>The results showed that life cycle of <em>S. pacificus </em>was 38–47 (41,60 ± 3,19) days: egg was 9–11 (10,20 ± 0,79) days, the first instar nymph was 3–4 (3,70 ± 0,48) days, the second instar nymph was 3–4 (3,90 ± 0,32) days, the third instar nymph was 3–4 (3,70 ± 0,48) days, the fourth instar nymph was 3–4 (3,80 ± 0,42) days, and the fifth instar nymph was 3–4 (3,60 ± 0,52) days. Age of female was 13–17 (15,30 ± 1,34) days. It was longer than age of male which was 8–12 (10,10 ± 1,20) days. Female could produce 181–214 (197,60 ± 11,64) eggs during its life. The sex ratio was 1:1,98.</p>

Biology and development of galls induced by Lopesia sp. (Diptera: Cecidomyiidae) on leaves of Mimosa gemmulata (Leguminosae: Caesalpinioideae)

2018 ◽  
Vol 66 (2) ◽  
pp. 161 ◽  
Author(s):  
Elaine Cotrim Costa ◽  
Renê Gonçalves da Silva Carneiro ◽  
Juliana Santos Silva ◽  
Rosy Mary dos Santos Isaias
Keyword(s):  
Growth And Development ◽  
Glandular Trichomes ◽  
Early Growth ◽  
Vascular Bundles ◽  
Nutritive Tissue ◽  
Development Stages ◽  
First Instar ◽  
Galling Insects ◽  
Late Growth

Analyses of gall biology and development allow determination of morphogenesis events in host-plant organs that are altered by galling insects. Currently, we assume that there is a correlation between Lopesia sp. instars and the alterations in gall tissues on Mimosa gemmulata that generate the gall shape. The development of Lopesia sp. (three larval instars, pupae and adult) correlates positively with gall growth, especially on the anticlinal axis. First-instar larvae are found in galls at the stage of induction, Instar 2 in galls at early growth and development, Instar 3 in galls at late growth and development, pupae in galls at maturation, and the adult emerges from senescent galls. At induction, the larva stimulates cell differentiation in pinnula and pinna-rachis tissues on M. gemmulata. At early growth and development stages, cell division and expansion are increased, and non-glandular trichomes assist gall closing. Homogenous parenchyma and neoformed vascular bundles characterise late growth and development. At maturation, tissues are compartmentalised and cells achieve major expansion through elongation. At senescence, galls open by the falling of trichomes, and mechanical and nutritive cells have thickened walls. The neoformed nutritive tissue nurtures the developing Lopesia sp., whose feeding behaviour influences the direction of cell elongation, predominantly periclinal, determinant for gall bivalve shape.

Taxonomy of Kermes greeni Bodenheimer (Hemiptera: Coccoidea: Kermesidae) with a new synonymy

Zootaxa ◽  
2012 ◽  
Vol 3545 (1) ◽  
pp. 67 ◽  
Author(s):  
MALKIE SPODEK ◽  
YAIR BEN-DOV ◽  
ALEX PROTASOV
Keyword(s):  
Adult Female ◽  
Instar Nymph ◽  
Type Material ◽  
First Instar ◽  
New Synonymy

The first-instar nymph and adult female of Kermes greeni Bodenheimer, 1931 are redescribed and a lectotype is designated. Kermes palestiniensis Balachowsky, 1953 is synonymized with K. greeni. This synonymy is based on a study of the type material of K. greeni and K. palestiniensis, as well as on fresh, topotypic material collected from Quercus calliprinos Webb in Israel.

Description of a new pest species of Hemilecanium Newstead (Hemiptera: Coccidae) on mango from Thailand, and a key to species of the genus

Zootaxa ◽  
2005 ◽  
Vol 1045 (1) ◽  
pp. 25 ◽  
Author(s):  
TAKUMASA KONDO ◽  
MICHAEL L. WILLIAMS
Keyword(s):  
Mangifera Indica ◽  
Scale Insect ◽  
Instar Nymph ◽  
Pest Species ◽  
Key To Species ◽  
Soft Scale ◽  
Adult Females ◽  
First Instar ◽  
A New Species ◽  
New Pest

The adult female and first-instar nymph of a new species of soft scale insect, Hemilecanium mangiferae Kondo & Williams sp. nov., are described and illustrated. This species was collected on the trunk and branches of mango, Mangifera indica L., in Nakhon Pathom and Sukhothai Provinces, Thailand. The insect can cause serious damage by depleting the host sap and by producing large amounts of honeydew on which sooty molds grow. Damage was severe on the local mango cultivar, Nam DokMai. Also included are a revised diagnosis of the genus, a revised key to the adult females of the five species currently placed in the genus, and a key to the known firstinstar nymphs.La hembra adulta y la ninfa del primer estadio de una nueva especie de escama blanda, Hemilecanium mangiferae Kondo & Williams sp. nov., se describe e ilustra. Esta especie fue colectada en el tronco y ramas del mango: Mangifera indica L. en las provincias de Nakhon Pathom y Sukhothai, Tailandia. Este insecto puede causar daños severos al mango deprivando el árbol de savia, y produciendo gran cantidad de melado cual induce el crecimiento de fumaginas. El daño fue más severo en un cultivar local conocido como Nam Dokmai. Tambien se incluyen una diagnosis revisada para el género, una clave revisada para las hembras adultas de las cinco especies actualmente incluidas en el género, más una clave para las ninfas del primer estadio conocidas.

Taxonomy of Toumeyella lomagundiae Hall and T. obunca De Lotto, and their transfer to Hallicoccus gen. nov. (Hemiptera: Coccoidea: Coccidae)

Zootaxa ◽  
2007 ◽  
Vol 1415 (1) ◽  
pp. 23-33
Author(s):  
TAKUMASA KONDO
Keyword(s):  
Instar Nymph ◽  
Scale Insects ◽  
Soft Scale ◽  
Taxonomic Key ◽  
Adult Females ◽  
First Instar

Two African soft scale insects, Toumeyella lomagundiae Hall and T. obunca De Lotto, are transferred to Hallicoccus gen. nov. The adult females of both species are redescribed, and the first-instar nymph of T. lomagundiae is described. A revised taxonomic key to separate the adult females is provided. The affinity of Hallicoccus gen. nov. with the genus Toumeyella Cockerell is briefly discussed.

Cissococcus Cockerell (Hemiptera: Coccoidea: Coccidae), a unique gall-inducing soft scale genus on Vitaceae from South Africa, with description of a new species

Zootaxa ◽  
2011 ◽  
Vol 2996 (1) ◽  
pp. 1 ◽  
Author(s):  
C. J. HODGSON ◽  
I. M. MILLAR ◽  
P. J. GULLAN
Keyword(s):  
South Africa ◽  
Type Species ◽  
Scale Insect ◽  
Instar Nymph ◽  
Closely Related Species ◽  
Soft Scale ◽  
First Instar ◽  
The Family ◽  
Gall Induction ◽  
A New Species

The gall-inducing genus Cissococcus Cockerell is revised to include two species. The family placement of Cissococcus has been uncertain, but characters of the first-instar nymph and adult male clearly show that Cissococcus is a soft scale insect (Coccidae) and is therefore the only member of the Coccidae known to induce a complex covering gall. All stages of the type species, C. fulleri Cockerell, are described and illustrated, plus the adult and third-instar female and first-instar nymph of a new, closely-related species, C. braini Hodgson & Millar sp. n. Both species are known only from wild vines in the southeast and C. fulleri also in the northeast of South Africa, but each induces a unique gall and each appears to be restricted to a different species of Rhoicissus (Vitaceae). The galls of each species are described and figured, and gall induction in the Coccidae is briefly discussed.

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