scholarly journals Reproductive response of Calanus helgolandicus. I. Abnormal embryonic and naupliar development

1995 ◽  
Vol 129 ◽  
pp. 85-95 ◽  
Author(s):  
SA Poulet ◽  
M Laabir ◽  
A Ianora ◽  
A Miralto
Keyword(s):  
Reproductive Response ◽  
Naupliar Development ◽  
Calanus Helgolandicus

scholarly journals Reproductive response of Calanus helgolandicus. II. In situ inhibition of embryonic development

1995 ◽  
Vol 129 ◽  
pp. 97-105 ◽  
Author(s):  
M Laabir ◽  
SA Poulet ◽  
A Ianora ◽  
A Miralto ◽  
A Cueff
Keyword(s):  
Embryonic Development ◽  
Reproductive Response ◽  
Calanus Helgolandicus

The seasonal abundance of the copepodite stages of Calanus helgolandicus and Pseudocalanus elongatus off Plymouth

1993 ◽  
Vol 73 (1) ◽  
pp. 109-122 ◽  
Author(s):  
E. P. Green ◽  
R. P. Harris ◽  
A. Duncan
Keyword(s):  
Seasonal Variation ◽  
Relative Abundance ◽  
Spring Bloom ◽  
Food Limitation ◽  
The Body ◽  
Seasonal Abundance ◽  
English Channel ◽  
Major Period ◽  
Naupliar Development ◽  
Calanus Helgolandicus

The relative abundance of the six copepodite stages (CI-CVI) of Calanus helgolandicus Claus (Copepoda: Calanoida) and Pseudocalanus elongatus Boeck (Copepoda: Calanoida) was recorded at a station in the English Channel throughout 1989. There was a pronounced seasonal variation in the abundance of the early stages. Increased recruitment from the nauplii corresponded in both species to rising primary production early in the year, producing small CI abundance peaks in March. The major period of naupliar development occurred after the April/May spring bloom. During seasonal peaks the CI and CII stages typically formed 40% of the copepodites of these species but were scarce at other times. The body carbon weight of Calanus and Pseudocalanus CIs decreased by 38% and 21% respectively from May to August, indicating an increase in food limitation for the nauplii. Summer was passed predominantly in the CIV and CV stage at low abundances.

scholarly journals Whole blood and blood components from vertebrates differentially affect egg formation in three species of anautogenous mosquitoes

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ruby E. Harrison ◽  
Mark R. Brown ◽  
Michael R. Strand
Keyword(s):  
Serum Albumin ◽  
Whole Blood ◽  
Digestive Enzyme ◽  
Vertebrate Host ◽  
Cell Protein ◽  
Blood Components ◽  
Blood Proteins ◽  
Serum Albumins ◽  
Egg Formation ◽  
Reproductive Response

Abstract Background Most female mosquitoes are anautogenous and must blood feed on a vertebrate host to produce eggs. Prior studies show that the number of eggs females lay per clutch correlates with the volume of blood ingested and that protein is the most important macronutrient for egg formation. In contrast, how whole blood, blood fractions and specific blood proteins from different vertebrates affect egg formation is less clear. Since egg formation is best understood in Aedes aegypti, we examined how blood and blood components from different vertebrates affect this species and two others: the malaria vector Anopheles gambiae and arbovirus vector Culex quinquefasciatus. Methods Adult female mosquitoes were fed blood, blood fractions and purified major blood proteins from different vertebrate hosts. Markers of reproductive response including ovary ecdysteroidogenesis, yolk deposition into oocytes and number of mature eggs produced were measured. Results Ae. aegypti, An. gambiae and C. quinquefasciatus responded differently to meals of whole blood, plasma or blood cells from human, rat, chicken and turkey hosts. We observed more similarities between the anthropophiles Ae. aegypti and An. gambiae than the ornithophile C. quinquefasciatus. Focusing on Ae. aegypti, the major plasma-derived proteins (serum albumin, fibrinogen and globulins) differentially stimulated egg formation as a function of vertebrate host source. The major blood cell protein, hemoglobin, stimulated yolk deposition when from pigs but not humans, cows or sheep. Serum albumins from different vertebrates also variably affected egg formation. Bovine serum albumin (BSA) stimulated ovary ecdysteroidogenesis, but more weakly induced digestive enzyme activities than whole blood. In contrast, BSA-derived peptides and free amino acids had no stimulatory effects on ecdysteroidogenesis or yolk deposition into oocytes. Conclusions Whole blood, blood fractions and specific blood proteins supported egg formation in three species of anautogenous mosquitoes but specific responses varied with the vertebrate source of the blood components tested.

scholarly journals Does Habitat Diversity Modify the Dietary and Reproductive Response to Prey Fluctuations in a Generalist Raptor Predator, the Eurasian Buzzard Buteo buteo?

Birds ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 114-126
Author(s):  
Marek Panek
Keyword(s):  
Habitat Quality ◽  
Breeding Success ◽  
Common Vole ◽  
Habitat Diversity ◽  
Crop Fields ◽  
Buteo Buteo ◽  
Nestling Diet ◽  
Reproductive Response ◽  
Agricultural Habitat ◽  
Small Fields

Predators can modify their diet and demography in response to changes in food availability and habitat quality. I tested the prediction that some species can change their predation pattern, between specialist type and generalist type, depending on the complexity of habitat structure. It was hypothesized that their dietary response is stronger in diversified habitats than in simplified ones, but the opposite tendency occurs in the case of reproductive response. The nestling diet and breeding success of the Eurasian Buzzard Buteo buteo, the abundance of its main prey (the common vole Microtus arvalis), and that of the most important alternative prey group (passerines) were estimated over ten years in two types of agricultural habitat in western Poland, i.e., in the diversified habitat of small fields and the simplified habitat of large fields. The vole abundance was higher in large fields, but the abundance of passerines was greater in small fields. The frequency of voles in the Eurasian Buzzard nestling diet was higher in large fields than in small fields and increased with the abundance of this prey in crop fields. However, no difference in the relationship between the vole frequency in the diet of Eurasian Buzzards and the abundance of voles was found between the two habitat types. The breeding success of Eurasian Buzzards was dependent on the vole abundance, but this relationship did not differ between the two field types. It seems that the pattern of dietary and reproductive response of Eurasian Buzzards depends on the actual availability of individual prey species, which can be modified by habitat quality, rather than on relative prey abundance.

Secondary production of Calanus helgolandicus in the Western English Channel

2004 ◽  
Vol 313 (1) ◽  
pp. 29-46 ◽  
Author(s):  
Catherine Rey-Rassat ◽  
Delphine Bonnet ◽  
Xabier Irigoien ◽  
Roger Harris ◽  
Robert Head ◽  
...  
Keyword(s):  
Secondary Production ◽  
English Channel ◽  
Calanus Helgolandicus

On the Nutrition and metabolism of zooplankton IV. The forms of nitrogen excreted By Calanus

1967 ◽  
Vol 47 (1) ◽  
pp. 113-120 ◽  
Author(s):  
E. D. S. Corner ◽  
B. S. Newell
Keyword(s):  
Amino Acids ◽  
Positive Reaction ◽  
Laboratory Experiments ◽  
Long Island Sound ◽  
Acartia Tonsa ◽  
Nitrogenous Compounds ◽  
Nitrogenous Substances ◽  
Experimental Density ◽  
Island Sound ◽  
Calanus Helgolandicus

A study has been made of the nitrogenous compounds excreted by Calanus helgolandicus (Claus) collected at Plymouth.Most of the excreted nitrogen is in the form of ammonia which accounts for 60–100% (average 74.3%) of the total, and some of the remainder may be lost as urea. There is no evidence for the excretion of measurable amounts of amino acids.Whether the animals are starved or fed they are primarily ammonotelic, and the quantity of ammonia produced at 10° C (3.33 μg/g. dry body wt/day) is not significantly changed when the animals are used at an abnormally high experimental density. This latter condition does, however, lead to the production of large quantities of additional nitrogenous substances that give a positive reaction with ninhydrin.IntroductionThe amounts of nitrogen excreted by zooplankton have been measured by several workers. Harris (1959) used the method of Riley (1953) to estimate the copious quantities of ammonia produced by animals (mainly Acartia tonsa and A. clausi) collected from Long Island Sound; Beers (1964), in laboratory experiments with the chaetognath Sagitta hispida, estimated the excreted ammonia by the procedure of Kruse & Mellon (1952); and Corner, Cowey & Marshall (1965) determined the ammonia excreted by Calanus helgolandicus and C. finmarchicus, using a ninhydrin technique described by Moore & Stein (1954). The methods employed by Harris and by Beers are specific for ammonia: that used by Corner et al. estimates nitrogenous substances (e.g. amino acids) in addition to ammonia, but certain tests were made which seemed to exclude the possibility that these substances contributed significantly to the nitrogen excreted by the animals.

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