Life history of Parastacoides tasmanicus tasmanicus Clark, a burrowing freshwater crayfish from south-western Tasmania

1994 ◽  
Vol 45 (4) ◽  
pp. 455 ◽  
Author(s):  
P Hamr ◽  
A Richardson
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Cold Water ◽  
Detailed Examination ◽  
Breeding Cycle ◽  
Freshwater Crayfish ◽  
Climate Conditions ◽  
History Of ◽  
Cold Water Temperature ◽  
Reproductive Females

The life history of the semi-terrestrial burrowing freshwater crayfish Parastacoides tasmanicus tasmanicus was studied in the wet heathlands of south-western Tasmania. Data on seasonal reproduction, fecundity and growth were obtained from regular monthly sampling over a period of two years. The development of gonads, size at maturity, sexual dimorphism and reproductive condition were determined by detailed examination of changes in reproductive morphology and gonad condition. P. t, tasmanicus attains maturity at a relatively late age (3-5 years) and large size (25-30 mm carapace length) and has a long life span (< 10 years) and a slow and variable growth rate. The growth rate appears to be a function of cold water temperature and low-nutrient diets. Males reach sexual maturity at a smaller size than do females. Mating and spawning, which closely follow the female moult, occur in early autumn when males and reproductive females pair within their burrow systems; eggs are carried over winter and hatch early the following summer, and young remain attached to their mothers until mid summer. Mature females appear to exhibit a biennial moulting and breeding cycle, an apparently unique strategy among parastacid crayfish, which is probably a result of the cooler climate conditions in Tasmania.

Laboratory studies on the life-history of Valanga nigricornis nigricornis (Burm.) (Orth., Acrididae)

1971 ◽  
Vol 60 (3) ◽  
pp. 439-446 ◽  
Author(s):  
M. L. Kok
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life Cycle ◽  
External Genitalia ◽  
Oviposition Period ◽  
Growth Stages ◽  
Laboratory Studies ◽  
Laboratory Conditions ◽  
History Of

Descriptions are given of all growth stages of Valanga nigricornis nigricornis (Burm.). The hopper instars (normally six in the male and seven in the female) could be distinguished by the development of the external genitalia. Under laboratory conditions (mean 27–9°C and 80% r.h.), the life-cycle was completed in 6½–8½ months, and the females had a mean fecundity of 158. Crowding slowed the growth rate of the adults, extended the pre-oviposition period from 60 to 65 days at 30–9°C and reduced fecundity. It is concluded that the low fecundity and slow life-cycle preclude the possibility of the species becoming a widespread pest.

scholarly journals Experimental determination of cold water temperature at the inlet to solar water storage tanks

2019 ◽  
Vol 116 ◽  
pp. 00106 ◽  
Author(s):  
Miroslaw Zukowski
Keyword(s):  
Water Temperature ◽  
Cold Water ◽  
Tap Water ◽  
Water System ◽  
District Heating ◽  
Hot Water ◽  
Storage Tanks ◽  
Climate Conditions ◽  
Cold Water Temperature

In the present work, results of experimental research on the mains water temperature supplying the Solar Domestic Hot Water system in the period from 2016 to 2018 are shown. The test object is located in the Hotel for Research Assistants on Bialystok University of Technology campus in Poland. One of the elements that will guarantee the correct energy balance of a hot tap-water system is the exact determination of the cold water temperature. The aim of this study is estimation of the temperature of the mains water flowing into the district heating substation and the water feeding directly the heat storage tanks. The research results showed that the average value of the cold water was 14.09°C during the 3 years of measurements. Moreover, it was shown that this temperature increased by about 0.4°C as a result of heat exchange with the air inside the substation. In the article, the author proposed modifications of coefficients in a commonly used model developed by National Renewable Energy Laboratory for determining the temperature of mains water in energy simulations. The proposed changes allow for accurate modelling of the cold water temperature under the climate conditions of north-eastern Poland.

The Symbiosis of Acarid Mites, Genus Ctenocolletacarus (Acarina, Acariformes), and Stenotritid Bees, Genus Ctenocolletes (Insecta, Hymenoptera)

1987 ◽  
Vol 35 (5) ◽  
pp. 459 ◽  
Author(s):  
TF Houston
Keyword(s):  
Life History ◽  
Circumstantial Evidence ◽  
Host Larva ◽  
Breeding Cycle ◽  
Brood Cell ◽  
Larval Host ◽  
History Of

Details of the life history of acarid mites of the genus Ctenocolletacarus have emerged from studies of nests of their hosts, Ctenocolletes albomarginatus and Ce. nicholsoni, and from rearing mites in the laboratory. The mites are closely associated with their hosts at all stages and their complete breeding cycle occurs in the hosts' sealed brood cells. Only the phoretic deutonymph leaves the cells. The mites, like their hosts, are univoltine. One to a few hypopi dismount from nesting females into each new brood cell and rapidly transform through non-mobile tritonymphs to adults of both sexes. Female mites oviposit on the ceiling of the cell during the host larva's early instars, giving rise to hundreds of larvae and then protonymphs by the time the host larva has completed feeding. Protonymphs metamorphose to hypopi once the host larva has defaecated and entered the prepupal phase. Hypopi remain with the dormant prepupa until the following season when they secrete themselves beneath the terga of the newly emerged adult bee. Circumstantial evidence, suggesting that hypopi are transmitted venereally between adult bees, is discussed. Adult, larval and protonymphal mites ingest pollen and the late protonymphal stage invades the faeces of the larval host. Sanitary control is a possible pay-off for the hosts.

The Life History of the Cirratulid Worm, Cirriformia Tentaculata, on an Intertidal Mudflat

1964 ◽  
Vol 44 (1) ◽  
pp. 47-65 ◽  
Author(s):  
J. D. George
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Seasonal Variation ◽  
Annual Cycle ◽  
Seasonal Fluctuation ◽  
Mortality Data ◽  
Intertidal Mudflat ◽  
History Of ◽  
Causes Of Mortality ◽  
Sexually Mature

The seasonal fluctuation in numbers of C. tentaculata was investigated from December 1959 until February 1962. The lowest numbers were recorded in April followed by a rapid increase in numbers during May. The magnitude of the increase varied from year to year, as also did the number of peaks that occurred during the summer months.The worm was shown to have an extended breeding season from the end of March to September during which several spawning ‘bursts’ took place. Experiments suggest that some spawning may occur when the mudflat is inundated by the rising tide, although spawning was not observed in the field.The population of C. tentaculata exhibited an annual cycle of growth which was influenced by the seasonal variation in temperature. Laboratory observations suggest that a temperature of about 20° C is optimal for the growth of young worms. The growth rate (8 mm/year) is slow compared with that of other polychaetes.It is tentatively concluded from the field mortality data that between 10 and 16 % of animals survive to an age at which they are sexually mature; between 6 and 8 % of each generation reach an age of 15 months. Causes of mortality in the population are briefly discussed.

scholarly journals Dispersal Patterns, Active Behaviour, and Flow Environment during Early Life History of Coastal Cold Water Fishes

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e46266 ◽  
Author(s):  
Ryan Stanley ◽  
Paul V. R. Snelgrove ◽  
Brad deYoung ◽  
Robert S. Gregory
Keyword(s):  
Life History ◽  
Early Life ◽  
Cold Water ◽  
Early Life History ◽  
Dispersal Patterns ◽  
Flow Environment ◽  
History Of

scholarly journals The biology of the common prawn, Leander serratus Pennant

1951 ◽  
Vol 30 (2) ◽  
pp. 333-360 ◽  
Author(s):  
G. R. Forster
Keyword(s):  
Experimental Study ◽  
Growth Rate ◽  
Life History ◽  
Additional Data ◽  
English Channel ◽  
Related Genus ◽  
History Of ◽  
The Common ◽  
And Migration ◽  
Recent Monograph

This work was undertaken at the suggestion of Mr F. S. Russell that little was known about the natural history of even so familiar a species as Leander serratus, the common prawn of the English Channel, which may at times form a valuable natural resource to the inshore fishermen. Attention was therefore chiefly concentrated on its growth rate and breeding biology. In spite of the long breeding season the statistical method of studying growth was adopted when preliminary results appeared successful. By this method additional data could be obtained on distribution and migration. In the closely related genus Crangon, growth has been shown to be retarded under laboratory conditions (Nouvel & van Rysselberge, 1937), so that an experimental study could not be relied on to give a picture of the normal life history. Höglund's recent monograph (1943) has treated Leander squilla in great detail. However, this species differs considerably in size and distribution from L. serratus, and it was felt that a similar study in the Plymouth area would not be mere repetition; in fact the biology of L. squilla itself differs somewhat in the two districts.

The life history of Thysanoessa inermis (Krøyer) in the Bay of Fundy

1978 ◽  
Vol 56 (3) ◽  
pp. 492-506 ◽  
Author(s):  
David W. Kulka ◽  
S. Corey
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Pattern ◽  
Gonadal Development ◽  
Class I ◽  
Bay Of Fundy ◽  
Eye Morphology ◽  
Passamaquoddy Bay ◽  
History Of

A 4-year study of the life history of Thysanoessa inermis was conducted in Passamaquoddy Bay. A comparison of the growth pattern and eye morphology showed that Th. inermis in Passamaquoddy Bay is part of a Bay of Fundy population centered in the Grand Manan Basin. Spawning occurs in the spring and the young stages are found near the surface during the summer. Thysanoessa inermis lives for 2 years in the Bay of Fundy and spawns at the end of the 1st and 2nd years. Gonadal development is described in detail. Growth in both years is rapid during the summer months with little or no increase in size during the winter. The growth rate of the female surpasses that of the males in the 2nd year. The neglecta form of Th. inermis (year class 0 animals) lives in the middle to upper layers and is morphologically different from the inermis form (year class I animals) which lives in the deepest layers.

On a Chalcidoid Parasite bred from a Flea Larva

Parasitology ◽  
1929 ◽  
Vol 21 (1-2) ◽  
pp. 103-106 ◽  
Author(s):  
James Waterston
Keyword(s):  
Life History ◽  
New Genus ◽  
British Museum ◽  
Distinct Species ◽  
Detailed Examination ◽  
Tropical Medicine ◽  
London School ◽  
Related Genus ◽  
History Of

For the opportunity to examine the material on which the following descriptions are based I am indebted to the courtesy of Dr P. A. Buxton and Miss E. Sikes of the London School of Tropical Medicine, where the life-history of certain fleas is being studied. A detailed examination of the parasite showed it to be referable to the Pirenine tribe of the Miscogasteridae—a family of Chalcidoid wasps. The genus and species appeared to be new. The fact, however, that the parasite had been bred from a species of flea known to have been recently introduced into Britain suggested the advisability of comparison with American representatives of the Pirenine group. This has now been done by my friend Mr A. B. Gahan of the Bureau of Entomology, Washington, D.C., to whom my hearty thanks are due. As the result we are agreed that a new genus is required. Bairamlia n.g. has obvious affinities with Pirene Hal., but differs in antennal, neurational and propodeal characters. Ecrizotes Forst. (fide A. B. Gahan) may also be a nearly related genus. genus. As regards the species, I am satisfied that it is very different from anything described by Walker of which material is still extant in the British Museum. Mr Gahan, however, tells me that Pirene marylandensis Gir. (Canad. Ent. 48, p. 116, 1916) is a congeneric though distinct species.

Sign in / Sign up

Export Citation Format

Share Document