scholarly journals Use of Larval Size, Instead of Larval Stage, to Study the Ecology of a Stomatopod Crustacean Oratosquilla oratoria

1995 ◽  
Vol 61 (1) ◽  
pp. 165-166 ◽  
Author(s):  
Tatsuo Hamano ◽  
Takashi Kikkawa ◽  
Shunshiro Ueno ◽  
Ken-Ichi Hayashi
Keyword(s):  
Larval Stage ◽  
Larval Size ◽  
Oratosquilla Oratoria

scholarly journals Density and body size of the larval stages of the invasive golden mussel (Limnoperna fortunei) in two neotropical rivers

2012 ◽  
Vol 23 (3) ◽  
pp. 282-292 ◽  
Author(s):  
Vivianne Eilers ◽  
Márcia Divina de Oliveira ◽  
Kennedy Francis Roche
Keyword(s):  
Body Size ◽  
Larval Stage ◽  
Larval Density ◽  
Limnoperna Fortunei ◽  
Larval Size ◽  
Larval Stages ◽  
Positive Effects ◽  
Paraguay River ◽  
Body Sizes ◽  
Golden Mussel

AIM: The present study involved an analysis of the monthly variations in the population densities and body sizes of the different stages of planktonic larvae of the invasive golden mussel (Limnoperna fortunei), in the rivers Paraguay and Miranda; METHODS: The study was carried out between February 2004 and January 2005. Monthly collection of the plankton samples was accompanied by physical, chemical and biological analyses of the water; RESULTS: The Miranda River presented higher values of calcium, pH, alkalinity, conductivity and total phosphorous. Larval density varied from 0-24 individuals.L-1 in the Paraguay River, with a peak in March of 2004, while in the Miranda River, densities varied between 0-9 individuals.L-1 with a peak in February of 2004. No larvae were encountered during the coldest months, May and June. No significant correlations were found between environmental variables and larval density in either river. Only the valved larval stages were recorded. The "D" and veliger forms were most abundant; umbonate larvae were rare in the Miranda River samples. Mean body sizes of "D", veliger and umbonate larval stages were, respectively, 111, 135 and 152 µm, in the Paraguay River, and 112, 134 and 154 µm in the Miranda River. Principal Components Analysis indicated positive relationships between "D" larval stage size and the ratio between inorganic and organic suspended solids, while negative relationships were found between larval size and calcium and chlorophyll-<img border=0 width=7 height=8 src="/img/revistas/alb/2012nahead/ALB_AOP_230307car01.jpg">; CONCLUSIONS: The larvae were recorded in the plankton during most of the year, with the exception of the two colder months. Neither densities nor larval stage body sizes were significantly different between the two rivers. Possible positive effects of food and calcium concentrations on body size were not recorded. This species may be adapted to grow in environments with elevated sediment concentrations.

Active and passive dispersal of Centroberyx affinis (Berycidae) and Gonorynchus greyi (Gonorynchidae) larvae on the Sydney shelf

2000 ◽  
Vol 51 (3) ◽  
pp. 229 ◽  
Author(s):  
Kimberley A. Smith
Keyword(s):  
Continental Shelf ◽  
Larval Stage ◽  
Shelf Break ◽  
Outer Shelf ◽  
Size Distributions ◽  
Passive Dispersal ◽  
Larval Size ◽  
Larval Behaviour ◽  
Eastern Australia ◽  
Spawning Periods

Distributions of small and large larvae of Centroberyx affinis (Berycidae) and Gonorynchus greyi (Gonorynchidae) were examined along a shore-normal transect across the Sydney continental shelf, south-eastern Australia during January and April 1994. Both species were abundant, and 3016 individuals of C. affinis and 3184 individuals of G. greyi were taken. Distributions of small and large C. affinis reflected hydrographic variability and suggested passive dispersal. Previous observations of high year-class variability for this species may therefore reflect oceanographic variability during the larval stage. In contrast, the distributions of G. greyi only partially reflected hydrography and appeared to be influenced by larval behaviour at both sizes. Size distributions during each month indicated protracted spawning periods for both species. Spawning by C. affinis may have occurred over the inner shelf although the location was unclear because of the complexity of nearshore currents. Spawning by G. greyi probably occurred over the outer shelf. An increasing influence of larval behaviour with larval size on the distribution of G. greyi restricted larger individuals to the shelf break; this may have been a response to higher productivity in this region.

The early development of antenna and antennal sensilla in the noctuid moth, Agrotis segetum (Insecta: Lepidoptera)

1990 ◽  
Vol 48 (3) ◽  
pp. 502-503
Author(s):  
Eric Hallberg ◽  
Lina Hansén
Keyword(s):  
Cell Death ◽  
Stem Cell ◽  
Early Development ◽  
Larval Stage ◽  
Pupal Stage ◽  
Agrotis Segetum ◽  
Antennal Sensilla ◽  
Noctuid Moth ◽  
Standard Procedures

The antennal rudiments in lepidopterous insects are present as disks during the larval stage. The tubular double-walled antennal disk is present beneath the larval antenna, and its inner layer gives rise to the adult antenna during the pupal stage. The sensilla develop from a cluster of cells that are derived from one stem cell, which gives rise to both sensory and enveloping cells. During the morphogenesis of the sensillum these cells undergo major transformations, including cell death. In the moth Agrotis segetum the pupal stage lasts about 14 days (temperature, 25°C). The antennae, clearly seen from the exterior, were dissected and fixed according to standard procedures (3 % glutaraldehyde in 0.15 M cacaodylate buffer, followed by 1 % osmiumtetroxide in the same buffer). Pupae from day 1 to day 8, of both sexes were studied.

INTERACTIONS BETWEEN CYSTICERCUS FASCIOLARIS AND COMMON RATS

2017 ◽  
Vol 23 (2) ◽  
Author(s):  
SHASHI KIRAN
Keyword(s):  
Granulation Tissue ◽  
Larval Stage ◽  
Histopathological Examination ◽  
Sylvatic Cycle ◽  
Mature Larva ◽  
Hepatic Cysts ◽  
Cysticercus Fasciolaris ◽  
Taenia Taeniaeformis ◽  
Relationship Of ◽  
The Relationship

The objective of this study was to determine the relationship of C. fasciolaris with common rats. Cysticercus fasciolaris is the larval stage of Taenia taeniaeformis . Development of metacestodes ( Cysticercus fasciolaris) occur in the liver of rodents. An urban and a sylvatic cycle occurs. A total of 40 liver specimens of rats were examined. Histopathological examination revealed the presence of multiple hepatic cysts, and the C. fasciolaris larva was surrounded by granulation tissue. Large and separated ûbroblasts in different orientations with some neoplastic changes were seen in advanced hepatic cysticercosis. The bladder involved the larva and large chamber containing the small chamber and opalescent fluid. The scolex of the mature larva is distinctly large, bearing four lateral distinct suckers, a rostellum armed with double, and alternating rows of hooks.

Phoronida

2017 ◽  
Author(s):  
Judith Fuchs
Keyword(s):  
Life Cycle ◽  
Small Group ◽  
Larval Stage ◽  
Intertidal Zone ◽  
Marine Invertebrates ◽  
Tree Of Life ◽  
General Morphology ◽  
Family Level ◽  
Planktonic Larval Stage

This chapter describes the taxonomy of Phoronida, a small group of exclusively marine invertebrates found in most of the world's oceans from the intertidal zone to about 400 metres depth. Phoronids are meroplanktonic with a planktonic larval stage usually less than 2 mm in length and a benthic adult whose length ranges from a few cm up to 50 cm. The chapter covers their life cycle, ecology, and general morphology. It includes a section that indicates the systematic placement of the taxon described within the tree of life, and lists the key marine representative illustrated in the chapter (usually to genus or family level). This section also provides information on the taxonomic authorities responsible for the classification adopted, recent changes which might have occurred, and lists relevant taxonomic sources.

The larva of Psychoda (Philosepedon) humeralis Meigen (Diptera, Psychodidae)

Parasitology ◽  
1963 ◽  
Vol 53 (1-2) ◽  
pp. 155-156
Author(s):  
Kenneth G. V. Smith ◽  
L. W. Grensted
Keyword(s):  
Larval Stage ◽  
Sensu Stricto ◽  
Present Account ◽  
Generic Rank ◽  
Detailed Treatment

Satchell (1947) described and keyed the larvae of 14 of the 19 British species of Psychoda, but this study did not include P. humeralis Mg., presumably because the author accorded generic rank to Philosepedon and Threticus which would put them outside his study of Psychoda sensu stricto. The larva of P. humeralis has been briefly described by Spärck (1920), but his figures are rather crude. A detailed treatment of the larval head is given by Anthon (1943). The present account is offered to facilitate identification of this species in the larval stage when used in conjunction with Satchell's comprehensive paper.

Capture of conspecific planktonic larvae by the suspension-feeding gastropod Crepipatella peruviana: association between adult and larval size

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
G A Rivera-Figueroa ◽  
J A Büchner-Miranda ◽  
L P Salas-Yanquin ◽  
J A Montory ◽  
V M Cubillos ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Larval Mortality ◽  
Feeding Preference ◽  
The Other ◽  
Suspension Feeding ◽  
Adult Size ◽  
Free Living ◽  
Larval Size ◽  
Suspension Feeders ◽  
Planktonic Larvae

ABSTRACT Free-living, planktonic larvae can be vulnerable to capture and ingestion by adult suspension-feeders. This is particularly the case for larvae that settle gregariously in benthic environments where suspension-feeders occur at high densities. Larvae of gregarious suspension-feeding species are at particularly high risk, as adults of their own species often serve as cues for metamorphosis. We conducted laboratory experiments to assess the extent to which adults of the suspension-feeding caenogastropod Crepipatella peruviana would capture and ingest their own larvae. Experiments were conducted with adults of different sizes, with larvae of different ages and sizes, and in the presence or absence of phytoplankton. Adults captured larvae in all experiments. The presence of microalgae in the water did not influence the extent of larval capture. On average, 39% of larvae were captured during the 3-h feeding periods, regardless of adult size. However, up to 34% of the larvae that were captured on the gill were later discarded as pseudofaeces; the other 64% were ingested. The extent of capture by adults was not related to adult size, or to larval size and, thus, to larval age. Our results suggest that the filtration of congeneric larvae by adult C. peruviana is a result of accidental capture rather than a deliberate feeding preference. Such ingestion could, however, still be an important source of larval mortality, especially when the advanced larvae of this species are searching for a suitable substrate for metamorphosis.

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