scholarly journals Abundance, Life History and Ligulosis in the Gobies (Teleostei) of the Inner Severn Estuary

1985 ◽  
Vol 65 (4) ◽  
pp. 951-968 ◽  
Author(s):  
P. N. Claridge ◽  
M. W. Hardisty ◽  
I. C. Potter ◽  
C. V. Williams
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Body Size ◽  
Stomach Contents ◽  
Power Station ◽  
Severn Estuary ◽  
Pomatoschistus Minutus ◽  
Spawning Areas ◽  
One Year ◽  
Number Of Individuals

Eight species of the Gobiidae were recorded in weekly samples taken between July 1972 and June 1977 from the intake screens of Oldbury Power Station in the inner Severn Estuary. Buenia jeffreysii, Aphia minuta, Gobius paganellus and Gobius niger occurred infrequently and Crystallogobius linearis was only common in the late spring and summer of 1975 and 1976. Pomatoschistus microps, which peaked in numbers in the winter, increased in abundance each year between 1972 and 1977. The most numerous gobies were those belonging to the Pomatoschistus minutus complex which were separated into P. minutus and P. lozanoi only between June 1974 and July 1975. Seasonal trends in the abundance of these two species were similar, with elevated numbers occurring between July and September 1974 and in January 1975. Gonadosomatic indices and other data indicate that the decline in numbers after the latter month represented an emigration to spawning areas further down the estuary or in the Bristol Channel. Although P. minutus attained a larger body size than P. lozanoi, both these species and P. microps typically had a one year life cycle with only a small number of individuals surviving for a further few months. The fecundity of P. lozanoi, which ranged from 410–2453 (mean 1270), was lower than that reported for P. minutus in this and other studies. Analysis of stomach contents showed that the diet of both species was similar, consisting predominantly of gammarids and mysids. While both species were infected with Ligula intestinalis, the incidence of infection and the parasite index was greater in P. lozanoi than in P. minutus.

THE ECOLOGY AND LIFE HISTORY OF RETUSA OBTUSA (MONTAGU) (GASTROPODA, OPISTHOBRANCHIA)

1967 ◽  
Vol 45 (4) ◽  
pp. 397-405 ◽  
Author(s):  
S. Tyrell Smith
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Span ◽  
High Tide ◽  
Breeding Period ◽  
Protandrous Hermaphrodite ◽  
History Of ◽  
Natural Breeding ◽  
One Year ◽  
Short Time

The habitat, diet, life history, and reproductive cycle of Retusa obtusa were investigated over a period of [Formula: see text] years in a population found in the Inner Harbour at Barry, Glamorgan, U.K. A technique was devised for extracting Retusa from the mud of this area. R. obtusa occurs in the topmost 3.5 cm of fine mud covering Barry harbor, which is immersed by the sea for only a short time at each high tide. The principal prey was found to be Hydrobia ulvae.The life cycle was found to be annual, the adults dying in spring, following the natural breeding season. Occasionally, a short extra breeding period occurs in the fall. The life span in no case greatly exceeded one year. Retusa is a protandrous hermaphrodite, and copulates in the fall. The eggs mature through the late fall and the winter, a few at a time, until oviposition occurs in the spring. The average number of eggs produced per individual was 33, deposited in 1–4 egg batches. Development is direct.

The real “fire ants”: colony size and body size of workers influence the fate of boreal sand hill ants (Hymenoptera: Formicidae) after wildfires in Alberta, Canada

2014 ◽  
Vol 147 (4) ◽  
pp. 396-404 ◽  
Author(s):  
James R.N. Glasier ◽  
Scott E. Nielsen ◽  
John H. Acorn
Keyword(s):  
Life History ◽  
Species Richness ◽  
Body Size ◽  
Colony Size ◽  
Fire Ants ◽  
Fire Ant ◽  
Pitfall Traps ◽  
Sand Hills ◽  
One Year ◽  
Nest Type

AbstractOver two summers following accidental May wildfires, total ant (Hymenoptera: Formicidae) forager catch and species richness did not change in jack pine woodlands on sand hills in central Alberta, Canada. However, one year after a fire, smaller ants, and those in smaller colonies, were more abundant in pitfall traps, based on analysis of response ratios for each ant species and relationships to a variety of life history and organismal traits. Nest type and polygyny had no effect on post-fire ant forager catch. The numerical responses of individual ant species appear to be idiosyncratic, but three species of ants that are sand specialists were found to be particularly resilient to fire.

Zooplankton Productivity

2017 ◽  
Author(s):  
Andrew G. Hirst
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Body Size ◽  
Secondary Production ◽  
Vital Rates ◽  
Production Rates ◽  
Ecological Traits

Zooplankton is a term used to describe the heterotrophic plankton, including both metazoans (multicellular animals) and single-celled protozoa such as ciliates and flagellates. Zooplankton encompass a great diversity of phyla, with an array of life history and ecological traits. Their body size spans over more than 15 orders of magnitude, and include species with a life cycle of less than a day to many years. This chapter describes the productivity of zooplankton. It first discusses the importance of determining life history and vital rates of zooplankton. It then examines the major ways in which growth and secondary production rates are determined. Finally, it explores mechanistic and empirical frameworks to predict what controls these rates and why.

Natural Enemies of Sirex cyaneus, Fabr., in England and their Life-history

1928 ◽  
Vol 19 (1) ◽  
pp. 67-77 ◽  
Author(s):  
R. N. Chrystal ◽  
J. G. Myers
Keyword(s):  
Life History ◽  
Life Cycle ◽  
New Zealand ◽  
Pinus Radiata ◽  
Solid Wood ◽  
Host Larva ◽  
Young Larva ◽  
Larval Feeding ◽  
One Year ◽  
Whole Life Cycle

Rhyssa persuasoria and Ibalia leucospoides, both parasitic on Sirex cyaneus, have been studied at Oxford.Rhyssa lays its eggs in the burrow of and near to the almost or quite full-fed host larva or the pupa, by piercing the solid wood with itsovipositor. Feeding is entirely ectoparasitic and takes only a few weeks, during which the host larva may burrow a little further. The winter is passed by Rhyssa as a resting larva. Pupation takes place in the spring, and the whole life-cycle normally occupies one year.Ibalia oviposits in the young larva just before ormore rarely just after hatching, utilising the oviposition-bores of the Sirex for this purpose. The first-stage larva is elongate, with sickle-shaped mandibles, and larval feeding seems wholly endoparasitic. Sirex larvae parasitised by Ibalia confine their boring largely to the outer portions of the trunk, and usually make their final cell just under and approximately parallel to the surface. The life-cycle of Ibalia requires at least two years.Owing to the very different instars which they attack, there seems no risk of superparasitism of Ibalia by Rhyssa or vice versa, and it is therefore suggested that both species be introduced into New Zealand as a measure against Sirex juvencus, which is there very destructive to plantations of Pinus radiata.

scholarly journals Abundance, seasonality and size of Atlantic salmon smolts entrained on power station intake screens in the Severn Estuary

1994 ◽  
Vol 74 (3) ◽  
pp. 527-534 ◽  
Author(s):  
P.N. Claridge ◽  
I.C. Potter
Keyword(s):  
Atlantic Salmon ◽  
Standard Length ◽  
Condition Factor ◽  
Early Summer ◽  
Length Frequency ◽  
Power Station ◽  
Severn Estuary ◽  
Frequency Distributions ◽  
The Mean ◽  
One Year

Atlantic salmon smolts were sampled from the intake screens of the Oldbury power station in the inner Severn Estuary at weekly intervals between July 1972 and June 1977. These catches, and those taken over nearly three years from the nearby Berkeley power station, demonstrated that the abundance of smolts in the estuary peaked in autumn (October) and, to a far greater extent, in spring (April and May). However, small numbers of smolts were occasionally found in all other months of the year except July. Standard length-frequency distributions of smolts remained unimodal throughout the year. Lengths ranged from 76 to 187 mm, mean 130·2 ±1·87 mm (95% CL), and wet weights ranged from 5·4 to 68·0 g, mean 26·9 ±1·17 g. The mean monthly standard length of smolts increased slightly between the autumn of one year and the spring/early summer of the next year, suggesting that, on average, the former were six months younger than the latter. The condition factor was significantly greater in autumn (1·40) than in spring (1·23). It is estimated that the total number of salmon smolts entrained annually on the screens at Oldbury during the five years ranged from 92 to 791, with a mean of 405. Total estimated numbers at Berkeley ranged from 196 to 788 per annum. The numbers at Oldbury are lower than those estimated for the downstream migrants of the Twaite shad, another anadromous species, and far lower than those of the most abundant of the marine fish species that use the Severn Estuary as a nursery area.

scholarly journals Eco-evolutionary dynamics may show an irreversible regime shift, illustrated by salmonids facing climate change

2021 ◽  
Author(s):  
Junnosuke Horita ◽  
Yoh Iwasa ◽  
Yuuya Tachiki
Keyword(s):  
Climate Change ◽  
Life History ◽  
Body Size ◽  
Evolutionary Dynamics ◽  
Environmental Changes ◽  
Threshold Value ◽  
Masu Salmon ◽  
Assessment Model ◽  
Oncorhynchus Masou Masou ◽  
One Year

AbstractThe enhanced or reduced growth of juvenile masu salmon (Oncorhynchus masou masou) may result from climate changes to their environment and thus impact on the eco-evolutionary dynamics of their life-history choices. Male juveniles with status, i.e., if their body size is larger than a threshold, stay in the stream and become resident males reproducing for multiple years, while those with smaller status, i.e., their body size is below the threshold, migrate to the ocean and return to the stream one year later to reproduce only once. Since juvenile growth is suppressed by the density of resident males, the fraction of resident males may stay in equilibrium or fluctuate wildly over a 2-year period. When the threshold value evolves, the convergence stable strategy may generate either an equilibrium or large fluctuations of male residents. If environmental changes occur faster than the rate of evolutionary adaptation, the eco-evolutionary dynamics exhibit a qualitative shift in the population dynamics. We also investigated the relative assessment models, in which individual life-history choices are made based on the individual’s relative status within the juvenile population. The eco-evolutionary dynamics are very different from the absolute assessment model, demonstrating the importance of understanding the mechanisms of life history choices when predicting the impacts of climate change.

Life History and Habits of the Green Spruce Leaf Miner, Epinotia nanana (Treitschke) (Lepidoptera: Tortricidae)

1966 ◽  
Vol 98 (7) ◽  
pp. 693-699 ◽  
Author(s):  
L. Daviault ◽  
R. Ducharme
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Larval Stage ◽  
Climatic Conditions ◽  
Leaf Miner ◽  
One Year ◽  
Heavy Mortality

AbstractEpinotia nanana (Tr.) has become increasingly important in recent years in Quebec as it has caused severe defoliation of ornamental spruce trees in the Berthierville area, Quebec. The insect has a one-year life cycle and overwinters in the larval stage, mainly in the fifth instar, in a mined needle. Damage is most noticeable in the spring. Fairly heavy mortality, probably due to unfavourable climatic conditions, occurs among overwintering larvae. The amount of control exerted by parasites is always low.

scholarly journals Life History Phenology and Sediment Size Association of the Dragonfly Cordulegaster dorsalis (Odonata: Cordulegastridae) in an Ephemeral Habitat in Southwestern British Columbia

2006 ◽  
Vol 120 (3) ◽  
pp. 347 ◽  
Author(s):  
Laurie B. Marczak ◽  
John S. Richardson ◽  
Marie-Claire Classen
Keyword(s):  
British Columbia ◽  
Life History ◽  
Life Cycle ◽  
Systematic Sampling ◽  
Limited Evidence ◽  
Larval Instars ◽  
Sediment Size ◽  
Ephemeral Habitat ◽  
Organic Sediments ◽  
One Year

The life cycle of the dragonfly Cordulegaster dorsalis was studied over one year by systematic sampling of larvae in three intermittent headwater streams in southwestern British Columbia. We determined that larvae normally take three years to reach maturity, emerging throughout July and August. There is limited evidence suggesting a split cohort development, with early emergence after two years. Additionally, we tested whether larval instars were distributed randomly or if they occupied different sediment microhabitats. Smaller animals tend to be associated with smaller grained organic sediments, although there was high variation between the streams.

Life history of the frog Crinia signifera in Tasmania, Australia

2005 ◽  
Vol 53 (1) ◽  
pp. 21 ◽  
Author(s):  
B. Lauck
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
Reproductive Traits ◽  
Pitfall Trap ◽  
Male Reproductive Success ◽  
Female Life History ◽  
Primary Determinant ◽  
History Of ◽  
One Year

A pitfall-trap study was used to investigate the importance of body size, age, body condition (males only), season and growth history as determinates of male and female life-history fitness traits in a population of the frog Crinia signifera. Specimens were dissected to determine physiological characteristics and skeletochronology was used to determine age. Females lived longer and attained a larger size than males by delaying sexual maturity. Most females and males attained sexual maturity after three and two years, respectively; although eggs were found in females as young as one year old. Body size (but not age) was the primary determinant of fecundity, total reproductive output (clutch mass) and oviduct mass for females. Season was the predominant influence on egg size, with smaller eggs produced in summer than in other seasons. Direct investment in male gonads (testes size) was determined by body size and also by age. This, and the fact that sexual size dimorphism in amphibians is commonly female biased, suggests that male size is not necessarily the primary determinant of male reproductive success in C. signifera. Whereas selection on reproductive traits in females is likely to act predominantly on body size, selection in males is also likely to act on survival.

scholarly journals THE LIFE HISTORY OF "DIAPREPES ABBREVIATUS" L., AT RIO PIEDRAS, PUERTO RICO

1969 ◽  
Vol 20 (4) ◽  
pp. 883-914 ◽  
Author(s):  
George N. Wolcott
Keyword(s):  
Puerto Rico ◽  
Life History ◽  
Life Cycle ◽  
Parasitic Wasp ◽  
Diaprepes Abbreviatus ◽  
Full Size ◽  
History Of ◽  
One Year ◽  
Autumn And Winter ◽  
Pupal Chamber

1. The females of Diaprepes abbreviatus L. lay 5,000 or more (or less) eggs in as few as two months, May and June, or in as many as seven months at other times of the year, often living over twice as long as do the males after emergence from the soil. 2. The incubation period of all eggs is seven days. Larvae attain full size in two to four months. A diapause period is absolutely essential before pupation. The pupal period is about two weeks. Fully-formed adults remain within the pupal chamber for a variable period of weeks or months, the length of this period and that of the diapause period of the larva being subject to great variation. 3. The great variation in the duration of the diapause period of the larva and before the emergence of the adult from the pupal cell in the ground permits some individuals to complete their life-cycle (hatch ing of eggs to first egg-cluster laid by female, or to emergence of male from soil) in less than eight months, but for other individuals it may extend for eighteen months (hatching of egg to last egg-cluster laid by female, or to death of male). 4. Deviation from a one-year life-cycle is of tremendous value to Diaprepes abbreviatus L. in enabling its eggs to escape attack by a common parasitic wasp, Tetrastichus haitiensis Gahan, which is most abundant during the late spring, but very scarce during autumn and winter.

Sign in / Sign up

Export Citation Format

Share Document