SURVIVAL OF AEDES LARVAE IN CONSTANT AREA PONDS IN SOUTHERN ALBERTA (DIPTERA: CULICIDAE)

1983 ◽  
Vol 115 (2) ◽  
pp. 183-188 ◽  
Author(s):  
G. Pritchard ◽  
P. J. Scholefield
Keyword(s):  
Survival Rate ◽  
Low Temperatures ◽  
Pupal Stage ◽  
Mortality Rates ◽  
Water Levels ◽  
Daily Mortality ◽  
Larval Stages ◽  
Constant Area ◽  
Southern Alberta ◽  
Heavy Mortality

AbstractMosquito eggs were hatched by artificially flooding dry pond beds and estimates of population size were made through larval development for one population of Aedes spencerii, two of A. cataphylla, and three of A. vexans. Overall daily mortality rates were between 8 and 21% and survival to the pupal stage was generally less than 20%, even though water levels were maintained. Mortality appeared to be higher in early larval stages than in later larval stages. Predation was unimportant and survival rate may have depended on food supply or temperature or an interaction between the two. In normal ponds populations often suffer heavy mortality when ponds dry up before development is complete. A. cataphylla, a spring species, developed faster than A. vexans, a summer species, at low temperatures but more slowly at high temperatures.

scholarly journals Population dynamics of Saissetia oleae. Ι. Assessments of ροpulation and mortality

2017 ◽  
Vol 8 ◽  
pp. 53 ◽  
Author(s):  
E. T. Stratopoulou ◽  
Ε.Τ. Kapatos
Keyword(s):  
Overall Survival ◽  
Population Dynamics ◽  
Survival Rate ◽  
High Temperatures ◽  
Mortality Rates ◽  
Overall Survival Rate ◽  
Population Changes ◽  
Mortality Factors ◽  
Saissetia Oleae ◽  
Heavy Mortality

The population dynamics of Saisselia oleae (Oliv.) (Homoptera: Coccidae) was studied in Corfu during five successive yearly generations (1981-1986). Successive estimates of the population of S. oleae were obtained within each of the five yearly generations and survivorship curves were constructed showing the progressive re­duction of the living population within each generation and population changes from generation to generation. The calculated mortality rates indicate that the population of S. oleae suffers heavy mortality. The major mortality factors were high temperatures during summer, the action of predators, particularly during spring, and mortality of crawlers during summer. Overall survival rate was very low and corresponded to total generation mortality that ranged from 99.693% to 99.987%. It is assumed that variation in the action of mortality factors cause considerable I’l Uctuations of the S. oleae population.

Lamb survival in two hill flocks

1959 ◽  
Vol 1 (1) ◽  
pp. 85-91 ◽  
Author(s):  
A. F. Purser ◽  
G. B. Young
Keyword(s):  
Birth Weight ◽  
Survival Rate ◽  
Age Structure ◽  
Maternal Age ◽  
Mortality Rates ◽  
The Mean ◽  
Lamb Survival

The effects of birth weight, maternal age and parity on survival of single lambs have been studied in a Blackface and a Welsh Mountain flock.In both flocks the maximum survival rate was found to occur among lambs with birth weights just above the mean. Mortality increased as lambs' birth weight increased or decreased from the optimum, but was especially heavy at the lower extreme of the range of birth weights.Mortality decreased with age of dam to 14·3% for lambs from 4- to 6-year-old Blackface ewes and to 9·4% for lambs of 3- to 4-year-old Welsh ewes. Ewes having their first lambs gave mortality rates twice as great as for the mature ewes in the same flocks. The lower chances of survival of first born lambs irrespective of dam's age accounts for the apparent trend of mortality with maternal age in the Blackface.Changes in mortality rates associated with variation in lamb's birth weight and with the age structure of the ewe flock were estimated. Possible means of improvement of survival rate are discussed.

Age composition of the filarial vector Culex quinquefasciatus (Diptera: Culicidae) in Calcutta, India

1996 ◽  
Vol 86 (3) ◽  
pp. 223-226 ◽  
Author(s):  
G. Chandra ◽  
B. Seal ◽  
A.K. Hati
Keyword(s):  
Culex Quinquefasciatus ◽  
Average Duration ◽  
Mortality Rates ◽  
Gonotrophic Cycle ◽  
Daily Survival Rate ◽  
Daily Mortality ◽  
Age Composition ◽  
Adult Females ◽  
Vector Mosquito ◽  
Filarial Vector

AbstractAge composition of the filarial vector mosquito Culex quinquefasciatus (Say) was determined by examining the number of ovariolar dilatations of 1200 adult females from Calcutta. Average duration of the gonotrophic cycle was 4.5 days. The proportion parous, the daily survival rate and daily mortality rates of the natural population were 0.53, 0.87 and 13%, respectively. The oldest mosquito sampled in the study area passed eight gonotrophic cycles in its lifetime.

Quantitative investigations of the hydraulic connection between a large reservoir and a buried valley aquifer in southern Alberta

2005 ◽  
Vol 42 (5) ◽  
pp. 1461-1473 ◽  
Author(s):  
B D Smerdon ◽  
C A Mendoza ◽  
A M McCann
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Hydraulic Head ◽  
Water Levels ◽  
Groundwater Flow Model ◽  
Reservoir Level ◽  
Hydraulic Connection ◽  
Southern Alberta ◽  
Approximate Location ◽  
Pumping Rates

Quantitative investigations, including two aquifer tests and development of a three-dimensional (3D) groundwater flow model, were required to determine the hydraulic connection between an irrigation reservoir and a buried valley aquifer in southern Alberta. Evidence of seepage was detected in the buried valley aquifer 10 km east of the Pine Coulee reservoir at the onset of filling in 1999, when the reservoir level exceeded an elevation of 1035 m above sea level (a.s.l.). Concern for an increase in the local water table and the creation of artesian conditions in the aquifer prompted this study to determine the approximate location of a seepage window that appeared to be connecting the reservoir and aquifer. Observations of hydraulic head in the aquifer during the pumping tests revealed a barrier boundary when the reservoir level was at an elevation of 1035 m a.s.l. and a recharge boundary condition when the elevation exceeded 1039 m a.s.l. These data were used to calibrate a 3D groundwater flow model, which was needed to determine the hydraulic properties and approximate location of the leakage zone. The quantitative investigation showed that seepage likely occurred through the sideslopes of the flooded coulee, rather than through the low-permeability coulee floor sediments or the embankment dam. Further simulations illustrated the expected seepage rates at various reservoir supply levels and the pumping rates required for relief wells installed in the buried valley aquifer to maintain historic aquifer hydraulic head. A brief postanalysis indicated that the forecasted pumping rates were only 15% lower than have been required to maintain preconstruction water levels in the buried valley aquifer.Key words: dams, seepage analysis, groundwater modelling, buried valley aquifer, pumping test.

scholarly journals Effect of Leaves and Fruits Ethanolic Extract of Duranta repens on Mosquito Culex pipens pipens

2011 ◽  
Vol 8 (4) ◽  
pp. 870-876 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Life Cycle ◽  
Mortality Rate ◽  
High Mortality ◽  
Culex Pipiens ◽  
Ethanolic Extract ◽  
Pupal Stage ◽  
Fourth Generation ◽  
Larval Instars ◽  
Larval Stages ◽  
Biological Performance

The study aimes to investigate the effects of leaves & fruits ethanolic extract of Duranta repens L. on biological performance for all stages of life cycle of the mosquito Culex pipiens piepiens L., For this purpose the mosquitoes were reared in the laboratory till the fourth generation .Different concentrations of leaves (800,1000,1200,1400ppm) and fruits (800,1000,1200ppm) were tested on (eggs,larval stages,pupal stages and the adult stages). The results revealed that the extracts gave highest mortality rate for the eggs at(100%) compared with control,fruits extract shown highest mortality rate of the four larval instars (100%)at 1200ppm compared with leave extract at(80,50,33.33,20%).Also the extract caused a high mortality rate for pupal stage compared with fruits extract at(76.66,53.33%)respectively.Also ethanolic extract caused a 83.33,76.66% for male &femail. Developmental deformation was observed.. In conclusion, the findings of the present study indicate that the leaves &fruits extracts of Duranta repens L., , can be widely and effectively used in the control of mosquito.

Histological evidence of reproductive senescence in Atlantic herring (Clupea harengus)

2020 ◽  
Vol 98 (1) ◽  
pp. 73-78
Author(s):  
Hugues P. Benoît ◽  
Kadra Benhalima ◽  
Jenni L. McDermid
Keyword(s):  
Survival Rate ◽  
Relative Frequency ◽  
Natural Populations ◽  
Mortality Rates ◽  
Reproductive Period ◽  
Clupea Harengus ◽  
Atlantic Herring ◽  
Reproductive Senescence ◽  
Histological Evidence ◽  
Adaptive Explanation

Senescence is the age-specific decline in fitness of adult organisms principally associated with a decline in survival rate (actuarial senescence) and fecundity (reproductive senescence). Although common in natural populations of many taxa, there are few examples in fishes. A recent study found age-specific increases in the relative frequency of macroscopically non-reproductive Atlantic herring (Clupea harengus Linnaeus, 1758), consistent with reproductive senescence in a number of Canadian populations. However, a non-adaptive explanation for these patterns, unrelated to senescence, could not be definitively ruled out. Here, we present the results of histological examination of herring gonads undertaken to examine this and another hypothesis. The sample size of macroscopically senescent gonads was small (n = 4 females), a function of the low abundance of large, older, purportedly senescent, herring in these populations subjected to high mortality rates, and constraints on obtaining fresh samples. The results indicate that these fish were senescent and not merely skip spawning, providing further evidence of senescence and the occurrence of a post-reproductive period in herring in Atlantic Canada. Based on existing theory for the evolution of senescence, observations of actuarial senescence in Norwegian spring-spawning herring suggest that this population may also experience reproductive senescence and that the phenomenon may occur broadly in the species.

Host and geographic distribution of Skrjabinoclava spp. (Nematoda: Acuarioidea) in Nearctic shorebirds (Aves: Charadriiformes), and evidence for transmission in marine habitats in staging and wintering areas

1990 ◽  
Vol 68 (12) ◽  
pp. 2539-2552 ◽  
Author(s):  
P. L. Wong ◽  
R. C. Anderson
Keyword(s):  
Gulf Of Mexico ◽  
Pacific Coast ◽  
The United States ◽  
Larval Stages ◽  
Marine Habitats ◽  
The Pacific ◽  
Southern Alberta ◽  
Wintering Areas ◽  
Charadrius Wilsonia ◽  
Charadrius Semipalmatus

Twelve species of shorebirds belonging to the families Charadriidae (N = 3) and Scolopacidae (N = 9) were infected with 11 species of Skrjabinoclava and there was little overlap of parasites between these two families of birds. Most Skrjabinoclava spp. are transmitted apparently in marine staging and (or) wintering areas of their hosts, as indicated by the presence of larval stages of six species. There was no evidence that transmission occurs on the breeding grounds in freshwater habitats. Skrjabinoclava tupacincai, found predominantly in sanderlings (Calidris alba (Pallas)), is transmitted on the Pacific (Washington, California, Chile) and Atlantic coasts (New Jersey) in winter and the Gulf of Mexico (Florida and Texas) in winter and spring. Skrjabinoclava myersi was found, with a single exception, only in sanderlings, and transmission is apparently restricted to coastal Washington and California in winter. Skrjabinoclava bakeri, found predominantly in western sandpipers (Calidris mauri Cabanis), is transmitted on the Pacific coast (California) and in the Gulf of Mexico in winter. Skrjabinoclava morrisoni and Skrjabinoclava pusillae were found mainly in semipalmated sandpipers (Calidrispusilla (L.)). Both parasites are transmitted in the Gulf of Mexico in spring, but S. morrisoni is also transmitted in the Bay of Fundy in fall. Skrjabinoclava inornatae, found mainly in willets (Catoptrophorus semipalmatus (Gmelin)), is transmitted in Louisiana, Texas, and Peru in winter. Skrjabinoclava kritscheri was found only in marbled godwits (Limosafedoa (L.)), and it is suggested that infected birds collected in southern Alberta in spring acquired their infections while wintering along the Pacific coast of the United States. Skrjabinoclava hartwichi, found in black turnstones (Arenaria melanocephala (Vigors)) wintering in California and ruddy turnstones (Arenaria interpres (L.)) wintering in Peru, is transmitted along the Pacific coast of North America. Skrjabinoclava semipalmatae was found in semipalmated plovers (Charadrius semipalmatus Bonaparte) wintering in California. Skrjabinoclava wilsoniae was found in Wilson's plover (Charadrius wilsonia Ord) wintering in Texas and in a black-bellied plover (Pluvialis squatarola (L.)) migrating through southern Alberta in spring. Skrjabinoclava bartlettae was found in black-bellied plovers collected in southern Alberta in spring and Louisiana in winter.

scholarly journals Developmental stages of a common grass yellow butterfly, Eurema hecabe

2015 ◽  
Vol 24 (1) ◽  
pp. 73-81
Author(s):  
M Hasina Arju ◽  
Md Kowser Miah ◽  
Nousheen Parven ◽  
MA Bashar
Keyword(s):  
Survival Rate ◽  
Laboratory Condition ◽  
Incubation Period ◽  
Food Consumption ◽  
Developmental Stages ◽  
Average Duration ◽  
Pupal Stage ◽  
Larval Instars ◽  
Eurema Hecabe ◽  
Pierid Butterfly

Developmental stages of pierid butterfly (Lepidoptera: Pieridae) Eurema hecabe, duration and survival rate of developmental stages was studied in laboratory condition under 29 ± 3ºC temperature with RH 78 ± 2%. Egg, five larval instars and pupal stage were distinct. The average duration from egg to adult, incubation period, larval and pupal period was recorded 22.0 ± 0.7, 5.7 ± 6, 10.5 ± 0.4 and 6.5 ± 0.4 days, respectively. Twenty seven out of 34 larvae were successfully completed their whole 5 instars. Positive correlation among the larval instars, amount of food consumption and excretion of faeces were observed. About 65% pupae emerged as adult at laboratory condition. Dhaka Univ. J. Biol. Sci. 24(1): 73-81, 2015 (January)

History of the Herring Fishery and Review of Artificial Propagation Techiques for Herring in Japan

1985 ◽  
Vol 42 (S1) ◽  
pp. s222-s229 ◽  
Author(s):  
Shou Morita
Keyword(s):  
Survival Rate ◽  
Egg Production ◽  
Northwest Pacific ◽  
High Survival ◽  
High Survival Rate ◽  
Larval Stages ◽  
Production Techniques ◽  
History Of ◽  
License System ◽  
Food Conditions

According to written records, a Japanese herring fishery has been carried out since 1447, but statistical catch data were not recorded until 1870. The Japanese herring fishery has harvested the so-called Hokkaido spring herring, which spawned near the coast of Hokkaido from March to May. In 1897, the landings reached a peak of 975 000 tonnes but the resources were depleted year by year and this stock became extinct in the 1950's. During the 1960's, Japanese fleets were exploiting the herring stocks in the Northwest Pacific. However, since 1970 these fisheries were limited in their operations by the Japan–Soviet Fisheries Committee and eventually ceased in 1976. At the present time, the Japanese catch of herring is at a low level of several thousand tonnes. The Japanese license system was not designed to conserve the resources, and herring studies were weighted to fishing forecasts only. Many Japanese scientists believed that the strength of herring year-classes fluctuated with changes in food conditions in the early larval stages. Based on artificial egg production techniques developed recently in Japan, herring eggs were successfully hatched, and larvae were cultured artificially and raised to 66.3-mm juveniles with a high survival rate.

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