Comparison of Fossilized Schizochroal Compound Eyes of Phacopid Trilobites with Eyes of Modern Marine Crustaceans and Other Arthropods

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

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Hematodinium spp. infections in wild and cultured populations of marine crustaceans along the coast of China

Diseases of Aquatic Organisms ◽

10.3354/dao03119 ◽

2017 ◽

Vol 124 (3) ◽

pp. 181-191 ◽

Cited By ~ 7

Author(s):

JF Wang ◽

M Li ◽

J Xiao ◽

WJ Xu ◽

CW Li

Keyword(s):

Marine Crustaceans

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New species of bristletails of the genus Lepismachilis (Archaeognatha: Machilidae) from Serbia and Montenegro

Acta Entomologica Musei Nationalis Pragae ◽

10.2478/aemnp-2018-0049 ◽

2018 ◽

Vol 58 (2) ◽

pp. 577-587

Author(s):

Vladimir Kaplin

Keyword(s):

New Species ◽

Balkan Peninsula ◽

Species Group ◽

Compound Eyes ◽

Serbia And Montenegro ◽

Sensory Field ◽

Fore Femur ◽

Three New Species

Abstract The fauna of bristletails of the genus Lepismachilis Verhoeff, 1910 in Montenegro and Serbia includes only one species L. (Berlesilis) targionii (Grassi, 1887) with 2 + 2 eversible vesicles on abdominal urocoxites II–VI. Three new species of this genus are described: L. (Lepismachilis) prijepolja sp. nov., L. (Lepismachilis) limensa sp. nov. from Serbia, and L. (Lepismachilis) alexandrae sp. nov. from Montenegro. All described new species belong to the species group of the subgenus Lepismachilis s. str. with 2 + 2 eversible vesicles on abdominal urocoxites II–V. Lepismachilis prijepolja sp. nov. differs from L. y-signata Kratochvíl, 1945 and L. notata Stach, 1919 by the color, drawings and ratios of the compound eyes; ratios of sensory field on fore femur of male, number of divisions of ovipositor. Lepismachilis limensa sp. nov. differs from L. hauseri Bitsch, 1974 and L. abchasica Kaplin, 2017 by ratios of paired ocelli, sensory field on fore femur of male; ratios and chaetotaxy of maxillary and labial palps. Lepismachilis alexandrae sp. nov. differs from L. abchasica by the drawings of the compound eyes; ratios of paired ocelli, sensory field on fore femur of male; number of divisions of the parameres and gonapophyses. A list of the Machilidae occurring in Balkan Peninsula is also provided.

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In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

Scientific Reports ◽

10.1038/s41598-021-92230-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sándor Kecskeméti ◽

András Geösel ◽

József Fail ◽

Ádám Egri

Keyword(s):

Light Intensity ◽

Spectral Sensitivity ◽

Fungal Pathogens ◽

Light Trap ◽

Spectral Composition ◽

Wavelength Dependence ◽

Crop Damage ◽

Photon Flux ◽

Compound Eyes ◽

Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

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Dominant Enhancers of Egfr in Drosophila melanogaster: Genetic Links Between the Notch and Egfr Signaling Pathways

Genetics ◽

10.1093/genetics/147.3.1139 ◽

1997 ◽

Vol 147 (3) ◽

pp. 1139-1153 ◽

Cited By ~ 3

Author(s):

James V Price ◽

Edward D Savenye ◽

David Lum ◽

Ashton Breitkreutz

Keyword(s):

Notch Signaling ◽

Signaling Pathways ◽

Growth Factor Receptor ◽

Compound Eyes ◽

Egfr Signaling ◽

Wing Vein ◽

Developmental Context ◽

Epidermal Growth ◽

Hypomorphic Alleles ◽

Complex Signaling

The Drosophila epidermal growth factor receptor (EGFR) is a key component of a complex signaling pathway that participates in multiple developmental processes. We have performed and F1 screen for mutations that cause dominant enhancement of wing vein phenotypes associated with mutations in Egfr. With this screen, we have recovered mutations in Hairless (H), vein, groucho (gro), and three apparently novel loci. All of the E(Egfr)s we have identified show dominant interactions in transheterozygous combinations with each other and with alleles of N or Su(H), suggesting that they are involved in cross-talk between the N and EGFR signaling pathways. Further examination of the phenotypic interactions between Egfr, H, and gro revealed that reductions in Egfr activity enhanced both the bristle loss associated with H mutations, and the bristle hyperplasia and ocellar hypertrophy associated with gro mutations. Double mutant combinations of Egfr and gro hypomorphic alleles led to the formation of ectopic compound eyes in a dosage sensitive manner. Our findings suggest that these E(Egfr)s represent links between the Egfr and Notch signaling pathways, and that Egfr activity can either promote or suppress Notch signaling, depending on its developmental context.

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