Divergent responses in morphology and life history to an Asplanchna kairomone between attached and free-swimming Brachionus dorcas (Rotifera)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Shan Jiang ◽  
Yan Bai ◽  
Fan Sun ◽  
Le-Le Ge ◽  
Yi-Long Xi
Keyword(s):  
Life History ◽  
Free Swimming

The Sensitivity of Barnacles and Their Larvae to Copper and Mercury

1948 ◽  
Vol 25 (3) ◽  
pp. 276-298
Author(s):  
K. A. PYEFINCH ◽  
JOAN C. MOTT
Keyword(s):  
Life History ◽  
Toxic Effect ◽  
Sea Water ◽  
Short Interval ◽  
Sharp Decrease ◽  
Short Exposure ◽  
Sharp Change ◽  
Older Individuals ◽  
Free Swimming ◽  
Wide Range

1. Experiments on the toxic effects of copper and of mercury on various stages in the life history, nauplii, cyprids, metamorphosing cyprids and adults of acorn barnacles are described. Most of the work has been carried out on the appropriate stages of Balanus balanoides, but it has been supplemented, wherever possible, by parallel experiments using B. crenatus. 2. Cupric sulphate and mercuric chloride solutions were used as sources of the poisons, and the actual concentration of poison present was determined at the end of each experiment. The period of exposure to the poison was usually 6 hr. 3. A sharp decrease in sensitivity occurs, both in B. balanoides and B. crenatus, between the last naupliar stage and the cyprid. The relative sensitivity of the cyprid of B. balanoides to copper and to mercury is similar to that of the sixth stage nauplius, but the cyprid of B. crenatus is particularly insensitive to copper, but is more sensitive to mercury than that of B. balanoides. 4. Cyprids of B. balanoides only settle in the laboratory some 4 or 5 days after being taken in the plankton and during this period the sensitivity to copper and mercury increases. Settlement can be prevented by very low concentrations of copper and mercury, even though there are no obvious lethal effects. The cyprid of B. crenatus settles more readily in the laboratory, and little change in sensitivity seems to occur during the short interval between catching and settlement. 5. Metamorphosis of the cyprid of either B. balanoides or B. crenatus cannot be prevented by the concentrations of copper (up to 7 mg./l.) possible in sea water. This means that another sharp change in sensitivity occurs after the cyprid of the former species has settled but, because of the low sensitivity of the free-swimming cyprid of B. crenatus, such a change has not been detected for this species. 6. The young barnacle of both species immediately after metamorphosis is much more sensitive to copper than the metamorphosing cyprid. For B. balanoides the sensitivity, both to this poison and to mercury does not change significantly as the barnacle grows, but a small specimen of B. crenatus (less than one month old) is appreciably less sensitive, both to copper and to mercury, than slightly older individuals. 7. Copper and mercury appear to be roughly equi-toxic to the adult of B. balanoides; the adult B. crenatus is slightly more sensitive to copper and distinctly less sensitive to mercury than that of B. balanoides. 8. In view of these differences in sensitivity of the various stages in the life history of two closely related species, the results obtained with one species should not be held to apply to other species of barnacles. 9. A number of other experiments were carried out using the free-swimming cyprids of B. balanoides. Diluted sea water, though it has no toxic effect in itself over short exposure periods, markedly reduces the toxicity of both copper and mercury. Hypertonic sea water also reduces the toxicity of copper. The sensitivity of these larvae to either copper or mercury is not affected by the presence of sodium oleate. Exposure of these larvae to a wide range of copper concentrations in artificial sea water reveals certain anomalies which may be important in explaining the results obtained when they are exposed to mixtures of copper and mercury in natural sea water. The toxic effect of mercury seems to be similar in either natural or artificial sea water.

scholarly journals XXXI.—The Life-History of Xenopus lævis, Daud

1906 ◽  
Vol 41 (3) ◽  
pp. 789-821 ◽  
Author(s):  
Edward J. Bles
Keyword(s):  
Life History ◽  
Xenopus Laevis ◽  
Early Life ◽  
Early Life History ◽  
General Interest ◽  
Present Communication ◽  
Stages Of Development ◽  
Free Swimming ◽  
History Of

The present communication is intended to be the first of a series dealing with observations on the life-history of the Anura Aglossa and their anatomy at different stages of development. Xenopus lævis, with its small ova and protracted larval free-swimming stages, must necessarily form a basis for the study of the development of that other remarkable Aglossan, Pipa americana. Although the adult Aglossan is an aberrant and specialised Anuran, there are Urodele features in the development of Xenopas which make its embryology of great general interest. These primitive features, combined with others peculiar to the genus, impress a character upon the early life-history of this frog which is widely divergent from that of the Phaneroglossa with small ova.

Herpetomonas ludwigi (Kramář, 1950) n.comb., the trypanosomatid parasite of cranefly larvae (Diptera, Tipulidae)

Parasitology ◽  
1960 ◽  
Vol 50 (3-4) ◽  
pp. 351-363 ◽  
Author(s):  
Keith Vickerman
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Short Duration ◽  
Growth Phase ◽  
Developmental Cycle ◽  
Free Swimming ◽  
Attached Form

1. Herpetomonas ludwigi was found in 5–6% of larvae of Tipula paludosa in two out of three populations examined.2. The developmental cycle is confined to the enteric caeca of the host. From a study of smears and sections of these organs it was concluded that the life cycle was composed of the following stages:(a) A long-flagellated leptomonad stage which is short-lived and probably represents the form in which the flagellate enters the caeca from the mid-gut lumen; (b) a haptomonad or attached form in which the flagellum is short or absent: this probably represents the growth phase of the organism; (c) a crithidial phase which arises by a series of divisions from the haptomonad; (d) a small trypaniform stage which breaks free and lives in the lumen of the caecum; (e) a precystic flagellate; and (f) a small, thick-walled cyst.3. This species is characterized by its restriction to the enteric caeca and the short duration of free swimming as opposed to attached stages in the life history. This second feature is a corollary of the first. The periodic contraction of the enteric caeca makes attachment obligatory throughout the growth and division stages. These contractions also serve to void cysts into the mid-gut whence they leave the larva with its dejecta to infect other larvae.

An Investigation of the Life History and Propagation of the Sockeye Salmon (Oncorhynchus nerka) at Cultus Lake, British Columbia. No. 5. The Life history cycle of the 1926 year class with Artificial Propagation involving the liberation of free-swimming fry.

1936 ◽  
Vol 2 (3) ◽  
pp. 311-333
Author(s):  
R. E. Foerster
Keyword(s):  
Life History ◽  
Sockeye Salmon ◽  
Age Groups ◽  
Complete Recovery ◽  
First Year ◽  
Commercial Fishing ◽  
Free Swimming ◽  
Rates Of Growth ◽  
True Values ◽  
Two Age Groups

From 1,949 sockeye salmon females in the run of 1926, 8,770,000 eggs were available. Of these approximately 1,174,000 (13.4%) were lost through 261 females dying before stripping. Since part of this loss was undoubtedly due to conditions imposed by the investigation, a second set of percentages based on egg content of the fish stripped is given. The true values lie between the two. Fry liberated in the spring of 1927 amounted to 5,916,500 (67.5% of total available eggs and 77.9% of eggs available for stripping). From these there migrated to sea 336,173 yearlings and 8,000 two-year-olds, representing 3.9% of total eggs and 4.5% of eggs available for stripping, and but 5.8% of total fry liberated. The yearling seaward migrants, which showed no change in size as the migration proceeded, were appreciably smaller than those in the 1927 migration, thus exhibiting an inverse relationship to the presumed populations in the lake during the first year. Scale-ring counts for the two age groups were made and rates of growth computed from scale measurements. Returning adults consisted of: 32 group (1929)—9 males; 42 group (1930)—2,327 males + 5,300 females; 52 group (1931)—149 females, a total of 7,785 adults—representing 0.09% of total eggs and 2.3% of seaward migrants. From 99,700 migrants marked by the removal of the adipose and both ventral fins, 1,340 adults (1.34%) returned to Cultus lake and 341 (0.34%) were taken in commercial fishing areas. The latter are not considered a complete recovery.

scholarly journals The Life History of Kellia Suborbicularis

1938 ◽  
Vol 22 (2) ◽  
pp. 447-451 ◽  
Author(s):  
Marie V. Lebour
Keyword(s):  
Life History ◽  
Gill Lamella ◽  
Free Swimming ◽  
Planktonic Larva ◽  
Large Shell ◽  
History Of

Kellia suborbicularis (Montagu) has long been known to be viviparous. Lovén (1848) mentions this fact and Jeffreys (1863, p. 227) quotes Mr Clark who “found in the ovary of one individual ova in an advanced state with fully formed testaceous fry.” It is probable, however, that these shelled larvae were in reality contained in the gill pouch where later workers have found them. Pelseneer (1935, p. 517) says that the eggs are incubated in the internal gill lamella, and this was also observed by myself.It is striking that although the shelled larva is extremely small when liberated (shell 0.064–0.08 mm. in length), the late planktonic larva is very large (shell 0.30–0.37 mm. in length) and one of the most conspicuous bivalve veligers in the plankton. This indicates a prolonged free-swimming life quite unlike that of the oyster, Ostraea edulis, whose shelled larvae are liberated only to lose the velum in a few days. These late larvae of Kellia have been kept in bowls and plunger jars in the Plymouth Laboratory until they metamorphosed and for months afterwards, growing into beautifully clear and transparent individuals which undoubtedly belonged to this species.Kellia suborbicularis is placed by Winckworth (1932) in the Erycinidae, but this family is closely related to the Leptonidae, Montacutidae and Galeommatidae, most or all of whose members are viviparous. Lovén (1848) described the young shelled stage of Montacuta ferruginosa and M. bidentata, the latter species now being referred by Winckworth toMysella. Both keep their young in the gill pouch until the shelled stage and Lovén's beautiful figures show that the early shelled stage in each of them is very like that of Kellia.

Micronereis nanaimoensis sp. n.: with some Notes on its Life-History

1953 ◽  
Vol 10 (2) ◽  
pp. 85-95 ◽  
Author(s):  
E. Berkeley ◽  
C. Berkeley
Keyword(s):  
British Columbia ◽  
Life History ◽  
Larval Development ◽  
Cold Water ◽  
Egg Laying ◽  
Egg Mass ◽  
Free Swimming ◽  
Definition Of

Micronereis nanaimoensis sp. n. is described from the region of Nanaimo, British Columbia. The definition of Micronereis is slightly emended to include the species. It differs from its only congener, M. variegata Claparède of Europe, in being much larger, in possessing palps, in having more varied setae and different specialized crotchets in the males, and in colour. Swarming, pairing and egg-laying occur from late March to the end of May. The eggs are moulded by the female into masses covered by jelly, which are deposited on leaves of Zostera, Ulva, or other seaweeds, near low-tide mark, and are accompanied by her in the jelly until the larvae become free-swimming. In the laboratory, larvae left the egg-mass after 10–16 days, in cold water. Larval development up to the three-segmented stage is illustrated, and supports the inclusion of Micronereis in Nereidae.

scholarly journals The Life History of Distoma luteum n. sp., with Notes on some Cercariae and Rediae found in S. Africa

Parasitology ◽  
1918 ◽  
Vol 10 (3) ◽  
pp. 311-319 ◽  
Author(s):  
J. D. F. Gilchrist
Keyword(s):  
South Africa ◽  
Life History ◽  
Intermediate Host ◽  
Fresh Water ◽  
Liver Fluke ◽  
Free Swimming ◽  
Preliminary Examination ◽  
History Of ◽  
Fresh Water Snail

Some years ago, in endeavouring to obtain various stages in the life history of the liver-fluke in South Africa for teaching purposes, I found that, although the parasite is fairly common on some farms in this country, the intermediate host had not yet been definitely ascertained. In Europe, as is well known, the intermediate host is the fresh-water snail Limnaea truncatula, but this species has not been recorded with certainty from South Africa. The commonest fresh-water snail here is Physa (Isidora) tropica and a preliminary examination of a few specimens of this mollusc from Muizenberg Lake revealed abundant stages of fluke very closely resembling those of the liver-fluke. Additional specimens procured from the neighbourhood also afforded abundant material of the same stages. The only difficulty in accepting this as a solution of the problem was that, though placed in the most favourable conditions, the free swimming form (cercaria) was never observed to encyst.

scholarly journals An organismal perspective on C. intestinalis development, origins and diversification

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthew J Kourakis ◽  
William C Smith
Keyword(s):  
Life History ◽  
Cell Division ◽  
Model Organism ◽  
Tree Of Life ◽  
Laboratory Model ◽  
Free Swimming ◽  
Adult Form ◽  
Sea Squirt ◽  
Swimming Larva ◽  
Free Swimming Larva

The ascidian Ciona intestinalis, commonly known as a ‘sea squirt’, has become an important model for embryological studies, offering a simple blueprint for chordate development. As a model organism, it offers the following: a small, compact genome; a free swimming larva with only about 2600 cells; and an embryogenesis that unfolds according to a predictable program of cell division. Moreover, recent phylogenies reveal that C. intestinalis occupies a privileged branch in the tree of life: it is our nearest invertebrate relative. Here, we provide an organismal perspective of C. intestinalis, highlighting aspects of its life history and habitat—from its brief journey as a larva to its radical metamorphosis into adult form—and relate these features to its utility as a laboratory model.

Life history characteristics of the fluvial shrimp Macrobrachium yui (Holthuis, 1950) (Decapoda, Palaemonidae) spawning in the cave streams in northern Laos

Crustaceana ◽  
2015 ◽  
Vol 88 (2) ◽  
pp. 164-183 ◽  
Author(s):  
Aloun Kounthongbang ◽  
Oulaytham Lasasimma ◽  
Pany Souliyamath ◽  
Keiichiro Iguchi ◽  
Sayaka Ito
Keyword(s):  
Life History ◽  
Physiological Condition ◽  
Gonadosomatic Index ◽  
River System ◽  
Morphological Development ◽  
Size Distributions ◽  
Free Swimming ◽  
Size Frequency Distribution ◽  
Migratory Patterns ◽  
Drifting Larvae

This study aims to understand the reproductive and larval characteristics and the migratory patterns of the shrimpMacrobrachium yui(Holthuis, 1950). We conducted monthly samplings of the adult, juvenile and larval shrimp at fixed points in the Xuang River system in northern Laos. We determined the seasonal changes in size frequency distribution, difference in size among sampling sites, occurrence of drifting larvae, and physiological condition of the shrimp. The size distributions ofM. yuidiffered significantly throughout the year among sections of the river system: small-sized juveniles occurred in the Xuang River, various size classes in the Pho Stream, and larger adults in the Bokengsakang cave stream. The gonadosomatic index of females is the highest in the Bokengsakang cave stream and the gonadosomatic index of males is the highest in the Pho Stream. Drifting larvae that had already completed morphological development for settlement on the substrate occurred only in the Bokengsakang cave stream, although the hatched larvae have a free-swimming larval period. The overall results indicate thatM. yuifemales spawn in the Bokengsakang cave stream after mating with males during or before migration to the cave stream, and the hatched larvae remain in the cave stream until settling on the bottom. The life history migration ofM. yuiis attributed to the early stages of the life cycle, depending strongly on the cave stream.

Interrelationships of factors of social development are more complex than Life History Theory predicts

2019 ◽  
Vol 42 ◽  
Author(s):  
Boris Kotchoubey
Keyword(s):  
Life History ◽  
Social Development ◽  
Life History Theory ◽  
Strong Correlations ◽  
Behavioral Features

Abstract Life History Theory (LHT) predicts a monotonous relationship between affluence and the rate of innovations and strong correlations within a cluster of behavioral features. Although both predictions can be true in specific cases, they are incorrect in general. Therefore, the author's explanations may be right, but they do not prove LHT and cannot be generalized to other apparently similar processes.

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