NOTES ON THE BIOLOGY OF TETROPIUM PARVULUM (COLEOPTERA: CERAMBYCIDAE) IN ALBERTA

1973 ◽  
Vol 105 (5) ◽  
pp. 757-760 ◽  
Author(s):  
A. G. Raske
Keyword(s):  
Life Cycle ◽  
Early Summer ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Excess Heat ◽  
Engelmann Spruce ◽  
Wood Borer

AbstractThe wood borer Tetropium parvulum Casey is an economically important borer of white and engelmann spruce logs in Alberta. It has a 1-year life cycle. The adults emerge in early summer, the larvae mature by September, overwinter in L-shaped galleries, and pupate in the spring. The L-shaped galleries penetrate the wood to an average of 25–35 mm. Four natural mortality factors were: a suspect disease, the parasite Rhimphoctona alaskensis (Ashmead), excess heat, and woodpeckers. Of these, the suspect disease was the most evident, killing 57% of the mature larvae in one sample.

Natural mortality from poor condition in Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Impact ◽  
Fish Muscle ◽  
Early Summer ◽  
Wild Fish ◽  
Natural Mortality ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Poor Condition

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.

scholarly journals Performance of the Natural Mortality Factors of Aphis gossypii (Hemiptera: Aphididae) as a Function of Cotton Plant Variety and Phenology

2018 ◽  
Vol 47 (2) ◽  
pp. 440-447 ◽  
Author(s):  
António Chamuene ◽  
Tamíris Alves Araújo ◽  
Gerson Silva ◽  
Thiago Leandro Costa ◽  
Paulo Geraldo Berger ◽  
...  
Keyword(s):  
Cotton Plant ◽  
Aphis Gossypii ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Plant Variety

The life-cycle of Bucephalus haimeanus Lacaze-Duthiers, 1854 from Cardium edule L.

Parasitology ◽  
1973 ◽  
Vol 67 (3) ◽  
pp. 341-350 ◽  
Author(s):  
R. A. Matthews
Keyword(s):  
Life Cycle ◽  
Cyst Wall ◽  
Adult Stage ◽  
Comparative Morphology ◽  
Early Summer ◽  
Host Tissue ◽  
Remaining Life ◽  
Estuarine Habitat ◽  
Main Site ◽  
First Time

Bucephalus haimeanus is shown to be an estuarine species. The cercaria from Cardium edule is briefly redescribed to include details of the nephridial system. The metacercaria is described for the first time, having been obtained experimentally in Pomatoschistus microps and Pleuronectes platessa. In Pomatoschistus microps it survives at least 10 months, development within this host being completed within 2 months. The main site of infection is the liver. Migration is completed within 1 h and in some instances within 10 min. During this period the metacercaria actively feeds on host tissue, the gut being greatly distended with food on encystment. A hyaline cyst wall is maintained throughout the remaining life of the metacercaria. ‘O’ group plaice are highly susceptible to invasion by B. haimeanus during early summer and 100% infections were recorded in catches from Ynys-las, Dovey Estuary, in June. Experiments showed that only 2% of the metacercariae survived more than two weeks and that ‘l’ group plaice were non-susceptible to infection. Plaice are therefore considered accidental hosts. The metacercaria was linked with the adult stage from Morone labrax on the basis of comparative morphology and the ecology of the hosts, the bass entering the estuarine habitat during the summer months. The adult is considered synonymous with Bucephalus minimus Stossich, 1887.

Mortality of Cocoons of the Larch Sawfly, Pristiphora erichsonii (Htg.), in Relation to Distance from Small-Mammal Tunnels

1959 ◽  
Vol 91 (9) ◽  
pp. 535-542 ◽  
Author(s):  
C. H. Buckner
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Natural Mortality ◽  
Mortality Factors ◽  
Forest Reserve ◽  
Pristiphora Erichsonii ◽  
Larch Sawfly ◽  
The Relationship

The relationship between the fate of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), and distance from small-mammal tunnels was studied during 1958 in the Whiteshell Forest Reserve of eastern Manitoba. The objects were to determine the distance that small mammals can detect cocoons and to observe possible effects of the interactions of small-mammal predation and other natural mortality factors of the insect. Additional analyses of the data provided information on the behaviour of the predators and the ecology of the prey insect.

Life cycles of four species of Pseudocalanus in Nova Scotia

1989 ◽  
Vol 67 (3) ◽  
pp. 552-558 ◽  
Author(s):  
I. A. McLaren ◽  
Estelle Laberge ◽  
C. J. Corkett ◽  
J.-M. Sévigny
Keyword(s):  
Life Cycle ◽  
Nova Scotia ◽  
First Generation ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Late Winter ◽  
Early Winter ◽  
Temperature Dependent ◽  
Scotian Shelf

The primarily arctic Pseudocalanus acuspes, relict in Bedford Basin, Nova Scotia, produces a first generation (G1) in late winter; most G1 individuals mature in late spring. The G1 then produces a G2, most of which "rest" in copepodite stages III and IV until early winter. These stages store large amounts of lipid in early summer, which slowly diminish subsequently. A small number of G2 individuals continue to develop at temperature-dependent rates, maturing in early autumn and producing G3 adults in November. Copepodites developing in winter and spring store less lipid. The primarily arctic Pseudocalanus minutus, rare in Bedford Basin and on the Scotia Shelf, is strictly annual, developing to a lipid-filled copepodite stage V after spawning in late winter. The arctic–temperate Pseudocalanus newmani is abundant on the Scotian Shelf, but may not be self-sustaining when advected into Bedford Basin. It stores little lipid and appears to have at least three mature generations at temperature-dependent intervals over Browns Bank between May and November. It may rest in winter, or its life-cycle synchrony by spring could result from food-limited development during winter. The temperate Pseudocalanus moultoni appears to have a life cycle similar to that of P. newmani, but was less common during summer on Browns Bank. These life cycles are appropriately adapted to the geographical ranges of the species, and show some parallels with species of Calanus.

Natural mortality of juvenile rabbits (Oryctolagus cuniculus ) in North Canterbury, New Zealand

1993 ◽  
Vol 20 (6) ◽  
pp. 815 ◽  
Author(s):  
DL Robson
Keyword(s):  
New Zealand ◽  
Soil Type ◽  
Oryctolagus Cuniculus ◽  
Early Summer ◽  
Late Spring ◽  
Natural Mortality ◽  
Marked Influence ◽  
Breeding Activity ◽  
Pasture Quality

Rabbit-breeding stops were monitored over 35ha of improved farmland, with relatively stable rabbit numbers, in North Canterbury, New Zealand. The number of stops dug varied seasonally, with most in spring, fewest in autumn. Pasture quality appeared to have a marked influence on breeding activity and productivity of the rabbits. Of the 427 breeding stops located, litters were found in 33%. Most (97%) of these stops were lined with grass and belly fur from the doe. Most juvenile rabbit mortality occurred prior to weaning. Of the 126 litters monitored, 38% were preyed upon, 29% drowned and 20% were either preyed upon or drowned prior to emergence. Young drowned when sufficient rainfall for a particular soil type caused flooding of stops. In all, 13% of litters were weaned and left the breeding stop, with late spring-early summer being the most favourable period for survival. Predator numbers were lowest during this period. Ferrets were the most numerous predator; cats and harriers were also present. Disease was not significant. Of those rabbits that emerged, approximately 50% survived to 14 weeks of age. Less-frequent drowning during a sequence of dry years may explain an increase in rabbit number observed in previous years. This may make it possible to predict the need for control.

An ecological study of the pasture scarab Aphodius Howitti hope.

1956 ◽  
Vol 4 (3) ◽  
pp. 259 ◽  
Author(s):  
PB Carne
Keyword(s):  
Life Cycle ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Mortality Factors ◽  
Annual Life Cycle ◽  
High Soil Moisture ◽  
Site Preferences ◽  
Eastern Australia ◽  
Small Cracks ◽  
Gravid Females

The larval stage of Aphodius howitti Hope is a pest of improved and sown pastures in south-eastern Australia. The great increase in pasture improvement and of stocking rates over the past 25-30 years have favoured the development of high numbers of this insect, largely because of its preference for leguminous pasture species, especially subterranean clover (Trifolium subterraneum L.). This paper describes a general study of the life-cycle, behaviour, food, and oviposition site preferences of the species and includes a discussion of the mortality factors likely to be of significance in regulating its numbers. The species has an annual life-cycle. Studies on its biology revealed that adult females lay two distinct batches of eggs. The larger batch (c. 35 eggs) is laid before the female feeds in dung, sometimes even before flight; the smaller (c . 15 eggs), after feeding. The presence of dung is therefore not necessary for the survival of the species which is often found at high densities in ungrazed turf. The factors initiating and influencing flight activity were studied in detail. Initiation is triggered by light of a particular intensity; the time of appearance of beetles in flight can be forecast accurately in relation to the time of sunset. Flights are favoured by high temperature, high soil moisture, and by low wind velocity. Unfed beetles fly upwind towards dung pads. Gravid females execute a circling, exploratory flight; they appear to seek out comparatively bare situations for oviposition and usually enter the soil through small cracks such as are made by germinating clover plants.

scholarly journals Genetic architecture of rainbow trout survival from egg to adult

2010 ◽  
Vol 92 (1) ◽  
pp. 1-11 ◽  
Author(s):  
HARRI VEHVILÄINEN ◽  
ANTTI KAUSE ◽  
HEIKKI KOSKINEN ◽  
TUIJA PAANANEN
Keyword(s):  
Life Cycle ◽  
Rainbow Trout ◽  
Genetic Architecture ◽  
Life Stage ◽  
Genetic Correlations ◽  
Early Period ◽  
Mortality Factors ◽  
Time To Death ◽  
Life Cycle Stages ◽  
Binary Character

SummarySurvival from birth to a reproductive adult is a challenge that only robust individuals resistant to a variety of mortality factors will overcome. To assess whether survival traits share genetic architecture throughout the life cycle, we estimated genetic correlations for survival within fingerling stage, and across egg, fingerling and grow-out stages in farmed rainbow trout. Genetic parameters of survival at three life cycle stages were estimated for 249 166 individuals originating from ten year classes of a pedigreed population. Despite being an important fitness component, survival traits harboured significant but modest amount of genetic variation (h2=0·07–0·27). Weak associations between survival during egg-fry and fingerling periods, between early and late fingerling periods (rG=0·30) and generally low genetic correlations between fingerling and grow-out survival (mean rG=0·06) suggested that life-stage specific survival traits are best regarded as separate traits. However, in the sub-set of data with detailed time of death records, positive genetic correlations between early and late fingerling survival (rG=0·89) showed that during certain years the best genotypes in the early period were also among the best in the late period. That survival across fingerling period can be genetically the same, trait was indicated also by only slightly higher heritability (h2=0·15) estimated with the survival analysis of time to death during fingerling period compared to the analysis treating fingerling survival as a binary character (h2=0·11). The results imply that (1) inherited resistance against unknown mortality factors exists, but (2) ranking of genotypes changes across life stages.

Life cycle, population dynamics and productivity of Ventrosia maritima in the Evros Delta (northern Aegean Sea)

2005 ◽  
Vol 85 (2) ◽  
pp. 375-382 ◽  
Author(s):  
Theodoros Kevrekidis ◽  
Thomas Wilke
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Outer Part ◽  
Dry Weight ◽  
Early Summer ◽  
Late Winter ◽  
Published Data ◽  
Annual Life Cycle ◽  
Frequency Method ◽  
Innermost Part

Life cycle, population dynamics and productivity of the larviparous mudsnail species Ventrosia maritima were investigated at low salinities (0·3–6 psu) in differentiated parts of a Mediterranean lagoon (Monolimni Lagoon). Monthly samples were collected during the period from February 1998 to February 1999 in both parts of the lagoon. Ventrosia maritima displayed an annual life cycle. Recruitment occurred in summer and autumn at the outer part of the lagoon and additionally in late winter at the innermost part. A positive correlation was found between the percentages of small individuals and salinity or sediment organic matter at the outer part. Growth practically ceased in winter. The mudsnail displayed remarkable densities and an increase in growth in spring at <1 psu indicating that it is highly tolerant to extremely low salinities. Population density showed a significant seasonal variation; it increased from early summer to autumn (30,000–40,000 individuals m−2) following the summer and autumn recruitment. No significant correlation between the density of V. maritima and several examined physicochemical variables was found; a negative correlation was observed between the density of the mudsnail and that of the co-occurring polychaete Streblospio shrubsolii. Secondary production calculated by the size–frequency method gave a mean annual density (N) of 9740 ind m−2, a mean biomass (B) of 1·66 g ash-free dry weight (AFDW) m−2 y−1, a production (P) of 4·51 g m−2 y−1 and a P:B ratio of 2·72 at the outer part of the lagoon and a N of 14,570 ind m−2, a B of 3·2 g AFDW m−2 y−1, a P of 9·9 g m−2 y−1 and a P:B ratio of 3·09 at the innermost part. At the innermost part of the lagoon, where the seawater renewal rate and hydro-dynamism were lower and the sediment finer and organically richer, V. maritima displayed more recruitment pulses, a larger body size and a denser and more productive population than the one at the outer part. Our findings are compared to published data for the direct-developing congeners V. ventrosa and V. truncata.

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