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.

Some Aspects of the Life History of Calanus plumchrus in the Strait of Georgia

1973 ◽  
Vol 30 (6) ◽  
pp. 811-815 ◽  
Author(s):  
John Fulton
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life Cycle ◽  
Breeding Period ◽  
Strait Of Georgia ◽  
History Of

Calanus plumchrus did not feed during the last 7 months of its life cycle and the fecundity of each female was dependent on the size of the animal. Each female produced an average of 535 eggs from 9.5 broods over a breeding period of 85 days. Eggs were released in water deeper than 300 m and were calculated to move towards the surface about 26 m/day. Growth from egg to stage V took about 100 days. Growth rate was calculated to be 10.6%/day.

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.

Studies on Demodex folliculorum Simon (1842). I. Life history

Parasitology ◽  
1961 ◽  
Vol 51 (1-2) ◽  
pp. 181-192 ◽  
Author(s):  
S. G. Spickett
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Span ◽  
Statistical Methods ◽  
Skin Surface ◽  
Birkbeck College ◽  
Demodex Folliculorum ◽  
Histological Data ◽  
History Of

1. Histological data are given about the location and frequency of the different stages of the life history of D. folliculorum in the pilo-sebaceous apparatus of man. These data are examined statistically and the relative durations of each stage and their movements in the follicle are deduced from them.2. A method of in vitro culture is described and data are given about the longevity of the various stages of the life history.3. Experiments on the behaviour of the different motile stages of the mite are described. It is concluded that the deutonymph is the distributive stage, and that distribution occurs over the skin surface.4. The life history is reconstructed by a synthesis of the evidence presented. The life-cycle lasts approximately 14½ days, the life span of each stage of it being: ovum 60 hr., larva 36 hr., protonymph 72 hr., deutonymph 60 hr., adult 120 hr. Interval between copulation and oviposition 12 hr.This work was largely carried out in the Department of Pathology of the Institute of Dermatology, London, and I wish to thank the Director of Pathology, Dr J. O. Oliver, for making available to me the facilities of his department, and for his advice and interest during the progress of the work. The photographs were prepared by Mr R. H. Lunnan of the Photographic Department of the Institute of Dermatology. I am indebted to the Dean of the Institute of Dermatology for permission to publish the photographs.I am grateful to Mr T. E. Hughes of the Department of Zoology, Birkbeck College, University of London, for his advice at all times, and to Miss Hilda Davies of the Department of Statistics, University of Sheffield, for help with statistical methods and to Mr W. Moseley, who prepared the text figures.Finally, I wish to express my thanks to Professor I. Chester Jones and Dr E. T. B. Francis of the Department of Zoology, University of Sheffield, for reading the manuscript and for their help in its preparation.

The reproduction and larval development of Nereis fucata (Savigny)

1959 ◽  
Vol 38 (1) ◽  
pp. 65-80 ◽  
Author(s):  
J. B. Brown-Gilpin
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Experimental Methods ◽  
Point Of View ◽  
Hermit Crabs ◽  
Special Importance ◽  
Reproductive Patterns ◽  
Complete Life Cycle ◽  
History Of ◽  
The Many

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.

scholarly journals A STUDY OF THE LIFE HISTORY OF TRICHOBILHARZIA CAMERONI SP. NOV. (FAMILY SCHISTOSOMATIDAE)

1953 ◽  
Vol 31 (4) ◽  
pp. 351-373 ◽  
Author(s):  
Liang-Yu Wu
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Room Temperature ◽  
Migratory Birds ◽  
Local Infection ◽  
Domestic Ducks ◽  
Ottawa River ◽  
Daughter Sporocyst ◽  
Physa Gyrina ◽  
History Of

A cause of swimmer's itch in the lower Ottawa River is Trichobilharzia cameroni sp. nov. Its life cycle has been completed experimentally in laboratory-bred snails and in canaries and ducks, and the various stages are described. The eggs are spindle-shaped. The sporocysts are colorless and tubular. Mother sporocysts become mature in about a week. The younger daughter sporocyst is provided with spines on the anterior end and becomes mature in about three weeks. The development in the snail requires from 28 to 35 days. A few cercariae were found to live for up to 14 days at 50 °C., although their life at 16° to 18 °C. was about four days. Cercariae kept at room temperature for 60 to 72 hr. were found infective. The adults become mature in canaries and pass eggs in about 12 to 14 days. Physa gyrina is the species of snail naturally infected. It was found in one case giving off cercariae for five months after being kept in the laboratory. Domestic ducks were found to become infected until they were at least four months old, with the parasites developing to maturity in due course; no experiments were made with older ducks. Furthermore, miracidia were still recovered from the faeces four months after the duck had been experimentally infected, and it is suggested that migratory birds are the source of the local infection.

The life history of Pleurogenoides malampuzhensis sp. nov. (Digenea: Pleurogenidae) from amphibious and aquatic hosts in Kerala, India

2013 ◽  
Vol 88 (2) ◽  
pp. 230-236 ◽  
Author(s):  
R. Brinesh ◽  
K.P. Janardanan
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Related Species ◽  
Growth And Development ◽  
Systematic Position ◽  
Patent Period ◽  
Hoplobatrachus Tigerinus ◽  
Life Cycle Stages ◽  
Muscle Tissues ◽  
History Of

AbstractThe life-cycle stages of Pleurogenoides malampuzhensis sp. nov. infecting the Indian bullfrog Hoplobatrachus tigerinus (Daudin) and the skipper frog Euphlyctiscyanophlyctis (Schneider) occurring in irrigation canals and paddy fields in Malampuzha, which forms part of the district of Palakkad, Kerala, are described. The species is described, its systematic position discussed and compared with the related species, P. gastroporus (Luhe, 1901) and P. orientalis (Srivastava, 1934). The life-cycle stages, from cercaria to egg-producing adult, were successfully established in the laboratory. Virgulate xiphidiocercariae emerged from the snail Digoniostoma pulchella (Benson). Metacercariae are found in muscle tissues of dragonfly nymphs and become infective to the frogs within 22 days. The pre-patent period is 20 days. Growth and development of both metacercariae and adults are described.

Analysis of a Population Sampling Method for the Lodgepole Needle Miner in Canadian Rocky Mountain Parks

1952 ◽  
Vol 84 (10) ◽  
pp. 316-321 ◽  
Author(s):  
R. W. Stark
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Sampling Method ◽  
Rocky Mountain ◽  
Fixed Time ◽  
Forest Stand ◽  
Population Sampling ◽  
Adequate Sampling ◽  
History Of ◽  
External Feeding

General.—The purpose of this paper is to analyse a sampling method devised to assess larval populations in an outbreak of the lodgepole needle miner, Recurvaria milleri Busck (Busck 1914, Hopping 1945).The problem of developing an adequate sampling method is intimately concerned with the life-history of the insect, the region of the outbreak and the nature of the forest stand in which the outbreak occurs. In sampling most defoliator populations the problem is made more difficult by external feeding and wandering habits, hence it is usually done in some relatively inactive stage at a fixed time. de Gryse (1934) describes the problems inherent in sampling these insects. The needle miner, however, is fixed in its location for most of its life-cycle and is therefore readily obtainable for study. The problem here is reduced to a statistical one, that of obtaining an acceptable sample i.e. within suitable error limits with due regard for existing variables.

scholarly journals LIFE HISTORY, NON-SPECIFICITY, AND REVISION OF THE GENUS CHORIOPTES, A PARASITIC MITE OF HERBIVORES

1957 ◽  
Vol 35 (6) ◽  
pp. 641-689 ◽  
Author(s):  
Gordon K. Sweatman
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Additional Species ◽  
Sheep And Goats ◽  
History Of ◽  
Parasitic Mite

Chorioptic mange mites have been reared in vitro on epidermal debris. The life history of the mite has been observed, and each stage in the cycle described. Mites from the cow, horse, goat, sheep, and llama have been shown to be identical biologically and morphologically, and the specific names of equi, caprae, and ovis have been synonymized with C. bovis. The in vitro life cycle has been completed on epidermal debris from a variety of wild Cervidae, Bovidae, and Equidae, as well as on material from several breeds of domestic cattle, horses, sheep, and goats. From these and other data, three additional species or subspecies of Chorioptes were synonymized also with C. bovis. Only one other species, namely C. texanus, remains in the genus.

Differences in the growth, form and life history of Plumularia setacea (Ellis and Solander) (Hydrozoa : Plumulariidae) in two contrasting habitats

1986 ◽  
Vol 228 (1251) ◽  
pp. 113-125 ◽  
Keyword(s):  
Life Span ◽  
Growth Form ◽  
Initial Growth ◽  
Modular Construction ◽  
Oriented Growth ◽  
History Of ◽  
Contrasting Habitats ◽  
One Year ◽  
Growth And Reproduction ◽  
Rapid Regrowth

P. setacea that grow on the hydroid Nemertesia antennina at a depth of 15m in Torbay, Devon, are mature when about two months old ; early sexual reproduction ensures continued colonization of N. antennina , which lives for only 4-5 months. Growth and reproduction of P. setacea occur throughout the year. The growth of the generally unbranched stolon is oriented toward the tip of the N. antennina hydrocaulus, which always bends downcurrent. The pinnate hydrocauli of P. setacea are held across the current in the most efficient position for feeding. The oldest tissue of P. setacea is continually resorbed towards the younger parts of the hydroid, leaving an empty perisarc, which eventually degenerates. This behaviour, together with the oriented growth of the stolon, means that the hydroids ‘move’ distally along the N. antennina hydrocauli. On concrete substrata at ELWS at Felixstowe, Suffolk, P. setacea reproduces only from June to August. The young hydroids may briefly achieve an exponential growth rate, but this probably occurs infrequently because of mortality and interference by predators and competitors. The initial growth of the stolon is unbranched ; subsequent branched growth produces a complex network of stolons, which covers the available substrata. The oldest tissue of these hydroids is also continually resorbed. In addition, in autumn the coenosarc of all hydrocauli is resorbed into the stolon and P. setacea overwinters as a dormant stolon. Rapid regrowth of large mature hydrocauli occurs in May and June from small sections of the stolon that are not destroyed during dormancy. These hydroids die after reproducing and therefore have a life-span of about one year. The modular construction of P. setacea , contrary to previous assumptions on hydroid biology, does not confer the potential for an infinite growth and life-span, but endows the potential for variable growth and form that enables P. setacea to survive, as opportunists, in these different habitats.

The life history of Scaphiostomum pancreaticum McIntosh, 1934 (Trematoda: Brachylaemidae)

1972 ◽  
Vol 50 (2) ◽  
pp. 201-204 ◽  
Author(s):  
Doris N. Jensen
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Gastric Juice ◽  
Tamias Striatus ◽  
History Of ◽  
Anguispira Alternata ◽  
Cercarial Emergence

The life cycle of the brachylaemid trematode Scaphiostomum pancreaticum McIntosh, 1934, was completed experimentally in the laboratory. Eggs were obtained from trematodes removed from naturally infected Tamias striatus. Eggs are mature when laid and hatch naturally only after ingestion by a snail. In vitro hatching and subsequent examination of the miracidium was accomplished in snail gastric juice. Sporocysts developed in Anguispira alternata and cercarial emergence began 129 days after infection. Metacercariae developed in the kidney of A. alternata, Triodopsis albolabris, and Haplotrema concavum and were infective to the chipmunk after 5 months, and ovigerous adults were obtained in 30 days. This is the first description of the life cycle of a member of this genus.

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