Ability of Spalangia endius (Hymenoptera: Pteromalidae) to Parasitize Bactrocera dorsalis (Diptera: Tephritidae) after Switching Hosts

We studied the parasitism capacity of Spalangia endius as a pupal parasite of Bactocera dorsalis after switching hosts. We used pupae of B. dorsalis and M. domestica as the hosts and studied parasitism by S. endius in the laboratory. The parasitism capacities were compared at different host densities and different parasitoid ages. The two functional responses of S. endius fitted a Holling Type II equation. More M. domestica were parasitized than B. dorsalis at all the densities. The ability of S. endius to control M. domestica was α/Th (parasitism capacity) = 32.1950, which was much stronger than that of control B. dorsalis, which was α/Th = 4.7380. The parasitism rate of wasps that had parasitized B. dorsalis had decreased by the emergence time of parasitoids. These results suggest that the parasitoid-pest ratio should be 1:25 to maintain a relatively stable parasitism rate for control of B. dorsalis. The S. endius colony reared on M. domestica successfully controlled a low-density population of B. dorsalis in the lab. We provide evidence suggesting that the parasitism capacity of S. endius needs to be improved.

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Effect of predation on the low-density dynamics of vendace: significance of the functional response

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-132 ◽

2001 ◽

Vol 58 (10) ◽

pp. 1909-1923 ◽

Cited By ~ 13

Author(s):

Outi Heikinheimo

Keyword(s):

Functional Response ◽

Brown Trout ◽

Salmo Trutta ◽

Dynamic Modelling ◽

Perca Fluviatilis ◽

Low Density ◽

Functional Responses ◽

Density State ◽

Brown Trout Salmo Trutta ◽

Stock Recruitment

During the past 20 years, there have been prolonged vendace (Coregonus albula) recessions in several Finnish lakes. Hypotheses have been proposed that predation by brown trout (Salmo trutta m. lacustris) or perch (Perca fluviatilis) on young-of-the-year vendace could prevent the recovery of the vendace stocks from a low-density state. In this study, dynamic modelling was applied to examine the effect of predation, assuming a dome-shaped spawning stockrecruitment relationship for vendace, type II or III functional responses to predation by brown trout and perch, and a constant rate of fishing. The results showed that the form of the functional response is crucial in determining the significance of the predation on vendace stocks that have a steep dome-shaped stockrecruitment relationship. In all cases, however, predation by perch had more effect than that by brown trout, probably due to perch occupying the pelagic zone when the vendace stock is sparse. This may make the mortality of vendace increase with decreasing population density (depensatory mortality) at certain density levels.

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Glycoprotein 330 and low density lipoprotein receptor-related protein mediate internalization of prourokinase and complexes of urokinase with pai-1 in type II pneumocytes

Fibrinolysis and Proteolysis ◽

10.1016/0268-9499(94)90362-x ◽

1994 ◽

Vol 8 ◽

pp. 28 ◽

Cited By ~ 1

Author(s):

M.Z. Kounnas ◽

S. Stefansson ◽

D.K. Strickland ◽

W.S. Argraves

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Low Density ◽

Lipoprotein Receptor ◽

Type Ii ◽

Related Protein ◽

Type Ii Pneumocytes ◽

Density Lipoprotein Receptor ◽

Lipoprotein Receptor Related Protein ◽

Pai 1

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Low‐Density Graphite Grains and Mixing in Type II Supernovae

The Astrophysical Journal ◽

10.1086/306551 ◽

1999 ◽

Vol 510 (1) ◽

pp. 325-354 ◽

Cited By ~ 134

Author(s):

Claudia Travaglio ◽

Roberto Gallino ◽

Sachiko Amari ◽

Ernst Zinner ◽

Stan Woosley ◽

...

Keyword(s):

Low Density ◽

Type Ii ◽

Density Graphite

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A fencing experiment on a high-density population of Microtus townsendii

Canadian Journal of Zoology ◽

10.1139/z77-151 ◽

1977 ◽

Vol 55 (7) ◽

pp. 1166-1175 ◽

Cited By ~ 40

Author(s):

Rudy Boonstra ◽

Charles J. Krebs

Keyword(s):

Survival Rate ◽

Breeding Season ◽

Population Regulation ◽

Control Area ◽

High Density ◽

Low Density ◽

Vole Population ◽

Sharp Decline ◽

Density Population ◽

Microtus Townsendii

If dispersal is prevented, a low-density vole population will increase to unusually high densities. A mouse-proof fence was constructed around a vole population that had already reached high density and both this population and one on a control area were live-trapped from January 1975 to November 1975. The population on the control remained at peak densities. The enclosed population increased to even higher density once the breeding season had started and had a higher survival rate than the control population. By midsummer the enclosed population had severely overgrazed the vegetation and went into a sharp decline. Dispersal losses from the control were estimated at 32% for males and 31% for females in these high-density populations. Microtus townsendii populations thus responded to a fence in a manner similar to that of other species that have been studied. This experiment indicates the importance of dispersal to population regulation in voles even at peak densities.

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Anatomy and physiology of Cattail as related to different population densities

Planta Daninha ◽

10.1590/s0100-83582015000100001 ◽

2015 ◽

Vol 33 (1) ◽

pp. 01-12 ◽

Cited By ~ 7

Author(s):

F.F. CORRÊA ◽

R.H. MADAIL ◽

S. BARBOSA ◽

M.P. PEREIRA ◽

E.M. CASTRO ◽

...

Keyword(s):

Growth Rate ◽

High Density ◽

Root Anatomy ◽

Low Density ◽

Typha Angustifolia ◽

Anatomy And Physiology ◽

Shoot Ratio ◽

Root Shoot Ratio ◽

Apoplastic Barriers ◽

Density Population

The objective of this work was to evaluate the effects of the population density of Typha angustifolia plants in the anatomical and physiological characteristics. Plants were collected from populations of high density (over 50% of colonization capacity) and low density (less than 50% of colonization capacity) and cultivated under controlled greenhouse conditions. Plants from both populations were grown in plastic trays containing 4 L of nutritive solution for 60 days. At the end of this period, the relative growth rate, leaf area ratio, net assimilatory rate, root/shoot ratio, leaf anatomy, root anatomy, and catalase and ascorbate peroxidase activities were evaluated. Plants from high density populations showed increased growth rate and root/shoot ratio. Low density populations showed higher values of stomatal index and density in leaves, as well as increased palisade parenchyma thickness. Root epidermis and exodermis thickness as well as the aerenchyma proportion of high density populations were reduced, these plants also showed increased vascular cylinder proportion. Only catalase activity was modified between the high and low density populations, showing increased values in low density populations. Therefore, different Typha angustifolia plants show differences in its anatomy and physiology related to its origins on high and low density conditions. High density population plants shows increased growth capacity related to lower apoplastic barriers in root and this may be related to increased nutrient uptake capacity.

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Maternal loading with very low-density lipoproteins stimulates fetal surfactant synthesis

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00021.2002 ◽

2002 ◽

Vol 283 (2) ◽

pp. L310-L318 ◽

Cited By ~ 16

Author(s):

Alan J. Ryan ◽

Jheem D. Medh ◽

Diann M. McCoy ◽

Ronald G. Salome ◽

Rama K. Mallampalli

Keyword(s):

Fatty Acids ◽

Knockout Mice ◽

Low Density Lipoproteins ◽

Alveolar Epithelial Cells ◽

Type Ii Cells ◽

Low Density ◽

Type Ii ◽

Very Low Density Lipoproteins ◽

Pregnant Rat ◽

Apolipoprotein E Knockout Mice

We examined whether administration of very low-density lipoproteins (VLDL) to pregnant rats increases surfactant phosphatidylcholine (PtdCho) content in fetal pre-type II alveolar epithelial cells. VLDL-triglycerides are hydrolyzed to fatty acids by lipoprotein lipase (LPL), an enzyme activated by heparin. Fatty acids released by LPL can incorporate into the PtdCho molecule or activate the key biosynthetic enzyme cytidylyltransferase (CCT). Dams were given BSA, heparin, VLDL, or VLDL with heparin intravenously. Radiolabeled VLDL given to the pregnant rat crossed the placenta and was distributed systemically in the fetus and incorporated into disaturated PtdCho (DSPtdCho) in pre-type II cells. Maternal administration of VLDL with heparin increased DSPtdCho content in cells by 45% compared with control ( P < 0.05). VLDL produced a dose-dependent, saturable, and selective increase in CCT activity. VLDL did not significantly alter immunoreactive CCT content but increased palmitic, stearic, and oleic acids in pre-type II cells. Furthermore, hypertriglyceridemic apolipoprotein E knockout mice contained significantly greater levels of DSPtdCho content in alveolar lavage and CCT activity compared with either LDL receptor knockout mice or wild-type controls that have normal serum triglycerides. Thus the nutritional or genetic modulation of serum VLDL-triglycerides provides specific fatty acids that stimulate PtdCho synthesis and CCT activity thereby increasing surfactant content.

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