Population decline and life-cycle changes in a phantom midge (Chaoborus flavicans) after introduction of planktivorous fish

2013 ◽  
Vol 58 (7) ◽  
pp. 1436-1446 ◽  
Author(s):  
Bishnu P. Regmi ◽  
Jan S. Wivegh ◽  
Anders Hobaek
Keyword(s):  
Life Cycle ◽  
Population Decline ◽  
Planktivorous Fish ◽  
Chaoborus Flavicans ◽  
Phantom Midge

scholarly journals The rise and fall of Anopheles arabiensis (Diptera: Culicidae) in a Tanzanian village

1995 ◽  
Vol 85 (1) ◽  
pp. 37-44 ◽  
Author(s):  
J.D. Charlwood ◽  
J. Kihonda ◽  
S. Sama ◽  
P.F. Billingsley ◽  
H. Hadji ◽  
...  
Keyword(s):  
Life Cycle ◽  
Survival Rate ◽  
Anopheles Arabiensis ◽  
Light Trapping ◽  
Population Decline ◽  
Malaria Vectors ◽  
General Applicability ◽  
Dry Spell ◽  
The Village

AbstractThe continual recruitment of new individuals makes it difficult to study both the survival of multivoltine mosquitoes, and the size of the infectious reservoir in narural populations of malaria vectors. During long-term surveillance of a population of Anopheles gambiae Giles sensu lato in a Tanzanian village by daily light trapping, a temporary dry spell resulted in the cessation of recruitment for a period of 33 days, and a decline in numbers of A. arabiensis Patton caught from over 2000 to less than 10 in a sentinel house. Traps placed elsewhere in the village indicated similar proportionate declines although numbers caught varied according to location. A survival rate of 83% per day was estimated from the rate of population decline. Survival was unrelated to the size of the mosquitoes. The infectious reservoir (the chance of a mosquito acquiring an infection) was estimated to be 2% per feed. The exploitation of fortuitous events which temporarily eliminate a single stage in the life cycle has general applicability in the study of the bionomics of multivoltine insects.

ON THE OCCURRENCE AND BIOLOGY OF NEPYTIA FREEMANI (LEPIDOPTERA: GEOMETRIDAE) IN UTAH

1971 ◽  
Vol 103 (1) ◽  
pp. 119-124 ◽  
Author(s):  
William H. Klein ◽  
Maxine W. Minnoch
Keyword(s):  
Life Cycle ◽  
Population Decline ◽  
Douglas Fir ◽  
Ground Vegetation ◽  
North Central ◽  
Permanent Damage ◽  
White Fir ◽  
Overall Effectiveness

AbstractNepytia freemani Munroe reached outbreak proportions in one area in north central Utah in 1965 and subsided in early 1967. The looper has a 1-year life cycle and overwinters in the egg stage. Larvae issue from eggs in mid-May, feed during the summer months, and begin pupation in late July. Adults appear in August and females lay clusters of small oval eggs on both sides of the needle. White fir is the preferred host but Douglas-fir is also fed on. Even though defoliation was extremely heavy, topkill was the only permanent damage. Starved larvae fed on ground vegetation in the understory. Parasitism was heavy but its overall effectiveness in causing the sudden population decline is unknown.

Chaoborus flavicans Meigen (Diptera, Chaoboridae) is a complex of lake and pond dwelling species: a revision

Zootaxa ◽  
2021 ◽  
Vol 4927 (2) ◽  
pp. 151-196
Author(s):  
JUKKA SALMELA ◽  
OSKARI HÄRMÄ ◽  
DEREK J. TAYLOR
Keyword(s):  
Species Complex ◽  
Fourth Instar ◽  
Dna Barcodes ◽  
Adult Males ◽  
European Species ◽  
Chaoborus Flavicans ◽  
Fourth Species ◽  
Shallow Ponds ◽  
Aquatic Predators ◽  
Phantom Midge

Chaoborus flavicans (Meigen) is a widespread and much studied lacustrine phantom midge. As larvae, these insects are important aquatic predators. Based on the available type material, morphology of immature stages and adults, their aquatic habitat, and DNA barcodes, C. flavicans is shown to be a composite of at least four species, with three of these named here. Chaoborus flavicans is primarily a lake-dwelling species with a Holarctic range. Chaoborus albipes (Johannsen, 1903 stat. rev.) and C. posio Salmela sp. n. are pond-dwelling Holarctic and north European species, respectively. The position of the larval subordinate mandibular tooth at the vertex of the second and fourth teeth is a synapomorphy of the Chaoborus flavicans species complex. We present an identification key to fourth instar larvae, pupae, and adult males. We also designate the lectotype and paralectotypes of Sayomyia rotundifolia Felt, 1904 (syn. nov. of C. albipes). We hypothesize that a fourth species of the species complex is present in Japan. Our revision indicates that Holarctic shallow ponds contain a hidden diversity of predators (C. albipes and C. posio sp. n.). 

scholarly journals CITIES THAT ARE LOSING INHABITANTS: AN ANALYSIS OF THE BRAZILIAN REALITY

2020 ◽  
Vol 6 ◽  
Author(s):  
Beatriz Rennó Biscalchim ◽  
Ana Barreira
Keyword(s):  
Life Cycle ◽  
Development Process ◽  
Population Decline ◽  
Urban Decline ◽  
Population Loss ◽  
Population Trajectory ◽  
Identification Analysis

Purpose: This article identifies the Brazilian cities that showed urban decline in the period between 1970 and 2010 based on the country's official census conducted by the IBGE (Brazilian Institute of Geography and Statistics). Based on this identification, analysis of the behaviors presented by the cities with population loss allows separate them according to the two theories that explain the loss of population: life cycle and persistent decline. Methodology: The article compares the Brazilian situation with countries from other continents, namely Europe, which also showed population decline in the cities. Findings: The results show a diversity of situations, whereby the population decline of cities is not a generalized phenomenon nor inevitable. Implication: This analysis allows the discussion about whether the loss of inhabitants in some cities is an inevitable part of a country's development process in the sense that as countries increase their development indices also increases the number of cities with population loss. Originality: This paper provides a comprehensive portrait of the lost of inhabitants in the Brazilian cities. The article is the first to analyze the population trajectory of all Brazilian cities, covering a period of four decades.

Predation by a visual planktivore perch (Perca fluviatilis) in a turbulent and turbid environment

2013 ◽  
Vol 70 (6) ◽  
pp. 854-859 ◽  
Author(s):  
Zeynep Pekcan-Hekim ◽  
Laura Joensuu ◽  
Jukka Horppila
Keyword(s):  
Escape Response ◽  
Interactive Effect ◽  
Perca Fluviatilis ◽  
Interactive Effects ◽  
Foraging Success ◽  
Chaoborus Flavicans ◽  
Perch Perca Fluviatilis ◽  
Prey Escape ◽  
Phantom Midge ◽  
Linear Decline

Turbulence and turbidity are thought to independently affect the foraging success of fish, but little is known about their interactive effects on the feeding of fish larger than a few centimetres. We experimentally tested for this interaction on the feeding of planktivorous perch (Perca fluviatilis). There was an interactive effect of root mean square (RMS) velocity (0, 1.3, 2.7, 5.5, and 18.3 cm·s−1) and turbidity (0, 30, and 60 nephelometric turbidity units; NTU) on perch feeding on phantom midge larvae (Chaoborus flavicans). In the 0 and 60 NTU conditions, there was no significant change in the feeding efficiency of perch. However, at 30 NTU, increasing turbulence enhanced perch feeding by increasing encounter rates and disabling the prey escape response. The proportion of encountered Chaoborus larvae that were consumed showed a linear decline with increasing turbulence under clear and 30 NTU conditions and a dome-shaped response under 60 NTU. The results indicate that turbulence has a strong effect on the post-encounter stages of the foraging cycle.

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

A freeze-fracture-etched study of the physarum polycephalum plasma membrane during early formation of the macroplasmodial stage

1993 ◽  
Vol 51 ◽  
pp. 346-347
Author(s):  
Randolph W. Taylor ◽  
Henrie Treadwell
Keyword(s):  
Plasma Membrane ◽  
Life Cycle ◽  
Growth Phase ◽  
Filter Paper ◽  
Physarum Polycephalum ◽  
Freeze Fracture ◽  
Petri Dish ◽  
Wire Screen ◽  
Wide Mouth ◽  
Sterile Filter

The plasma membrane of the Slime Mold, Physarum polycephalum, process unique morphological distinctions at different stages of the life cycle. Investigations of the plasma membrane of P. polycephalum, particularly, the arrangements of the intramembranous particles has provided useful information concerning possible changes occurring in higher organisms. In this report Freeze-fracture-etched techniques were used to investigate 3 hours post-fusion of the macroplasmodia stage of the P. polycephalum plasma membrane.Microplasmodia of Physarum polycephalum (M3C), axenically maintained, were collected in mid-expotential growth phase by centrifugation. Aliquots of microplasmodia were spread in 3 cm circles with a wide mouth pipette onto sterile filter paper which was supported on a wire screen contained in a petri dish. The cells were starved for 2 hrs at 24°C. After starvation, the cells were feed semidefined medium supplemented with hemin and incubated at 24°C. Three hours after incubation, samples were collected randomly from the petri plates, placed in plancettes and frozen with a propane-nitrogen jet freezer.

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