The life-histories of the bivalves Montacuta substriata and M. ferruginosa, ‘commensals’ with spatangoids

1966 ◽  
Vol 46 (3) ◽  
pp. 499-511 ◽  
Author(s):  
John Gage
Keyword(s):  
Special Reference ◽  
Life Histories ◽  
Larval Stages ◽  
Planktonic Larvae ◽  
Settlement And Metamorphosis ◽  
Planktotrophic Larvae

The life-histories of the erycinaceans Montacuta substriata and M. ferruginosa were investigated with special reference to the initiation of their ‘commensal’ associations. The planktotrophic larvae are released in summer as veligers after incubation within the adults, and they may spend several months in the plankton before settlement and metamorphosis. Larvae of both species, isolated from the Plymouth plankton, were reared to post-larval stages that were comparable with spat found associated with spatangoids. Some corrections are made of the identifications of planktonic larvae, of these and other Erycinacea, by previous authors. Experiments showed that, apart from being more active, the responses of walking post-larvae are similar to those I have described previously with adults. It is considered that the reactions operate, in an integrated manner similar to the adults, in initiating their associations with spatangoids; the behaviour of the adults in maintaining and re-establishing their associations would thus represent a retention of larval faculties. Possible reasons for the restriction of M. substriata to superficial burrowers and the less specific occurrences of small M. ferruginosa amongst spatangoids—including both deep and shallow-burrowing species—are discussed.

scholarly journals RNA-Seq reveals divergent gene expression between larvae with contrasting trophic modes in the poecilogonous polychaete Boccardia wellingtonensis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Álvaro Figueroa ◽  
Antonio Brante ◽  
Leyla Cárdenas
Keyword(s):  
De Novo ◽  
Juvenile Stage ◽  
Type I ◽  
Rna Seq ◽  
Mrna Synthesis ◽  
De Novo Transcriptome ◽  
Larval Stages ◽  
Divergent Gene ◽  
Genetic Mechanisms ◽  
Planktotrophic Larvae

AbstractThe polychaete Boccardia wellingtonensis is a poecilogonous species that produces different larval types. Females may lay Type I capsules, in which only planktotrophic larvae are present, or Type III capsules that contain planktotrophic and adelphophagic larvae as well as nurse eggs. While planktotrophic larvae do not feed during encapsulation, adelphophagic larvae develop by feeding on nurse eggs and on other larvae inside the capsules and hatch at the juvenile stage. Previous works have not found differences in the morphology between the two larval types; thus, the factors explaining contrasting feeding abilities in larvae of this species are still unknown. In this paper, we use a transcriptomic approach to study the cellular and genetic mechanisms underlying the different larval trophic modes of B. wellingtonensis. By using approximately 624 million high-quality reads, we assemble the de novo transcriptome with 133,314 contigs, coding 32,390 putative proteins. We identify 5221 genes that are up-regulated in larval stages compared to their expression in adult individuals. The genetic expression profile differed between larval trophic modes, with genes involved in lipid metabolism and chaetogenesis over expressed in planktotrophic larvae. In contrast, up-regulated genes in adelphophagic larvae were associated with DNA replication and mRNA synthesis.

STUDIES ON THE APOIDEA OF WESTERN NOVA SCOTIA WITH SPECIAL REFERENCE TO VISITORS TO APPLE BLOOM

1933 ◽  
Vol 9 (5) ◽  
pp. 443-457 ◽  
Author(s):  
C. E. Atwood
Keyword(s):  
Nova Scotia ◽  
Special Reference ◽  
Social Organization ◽  
Life Histories ◽  
Pupal Stage ◽  
Simple Type ◽  
Nest Construction ◽  
Wild Bees ◽  
Males And Females ◽  
Nova Scotian

This paper describes the results of studies on the wild bees of Nova Scotia, which were carried out in connection with apple pollination investigations in the Annapolis-Cornwallis Valley, Nova Scotia.The biology of the Apoidea in general is reviewed from the literature, and a list of bees taken on apple bloom is given. As the members of the genera Halictus and Andrena were found to be the most important native pollinators, the greater part of the paper is devoted to accounts of the habits and life histories of representative species.The members of the genus Andrena were found to have a simple type, such as is generally found among solitary bees. The females provision the nest and then die; the larvae develop to the pupal stage in their underground cells, then emerge as adults the following season. All Nova Scotian species studied were one-generation forms.The bees of the genus Halictus show a primitive social organization, more complex in some species than in others. The first brood consists of females only, which are apparently sterile and work at nest construction, the gathering of pollen, etc. They are followed later in the season by a brood of males and females; these females, after being fertilized, hibernate for the winter, while the males die in the fall. The hibernating habits of different species are described, and notes are given on some parasites and inquilines of the two genera.

Spatially dynamic maternal control of migratory fish recruitment pulses triggered by shifting seasonal cues

2018 ◽  
Vol 69 (6) ◽  
pp. 942 ◽  
Author(s):  
Daisuke Goto ◽  
Martin J. Hamel ◽  
Mark A. Pegg ◽  
Jeremy J. Hammen ◽  
Matthew L. Rugg ◽  
...  
Keyword(s):  
Life History ◽  
Early Life ◽  
Life Histories ◽  
Egg Production ◽  
Local Density ◽  
Early Life History ◽  
Biophysical Model ◽  
Larval Stages ◽  
Predation Mortality ◽  
Stability And Resilience

Environmental regimes set the timing and location of early life-history events of migratory species with synchronised reproduction. However, modified habitats in human-dominated landscapes may amplify uncertainty in predicting recruitment pulses, impeding efforts to restore habitats invaluable to endemic species. The present study assessed how environmental and spawner influences modulate recruitment variability and persistence of the Missouri River shovelnose sturgeon (Scaphirhynchus platorynchus) under modified seasonal spawning and nursery habitat conditions. Using a spatially explicit individual-based biophysical model, spawning cycle, early life-history processes (dispersal, energetics and survival) and prey production were simulated under incrementally perturbed flow (from –10 to –30%) and temperature (+1 and +2°C) regimes over 50 years. Simulated flow reduction and warming synergistically contracted spring spawning habitats (by up to 51%) and periods (by 19%). Under these conditions, fewer mature females entered a reproductive cycle, and more females skipped spawning, reducing spawning biomass by 20–50%. Many spawners migrated further to avoid increasingly unfavourable habitats, intensifying local density dependence in larval stages and, in turn, increasing size-dependent predation mortality. Diminished egg production (by 20–97%) and weakened recruitment pulses (by 46–95%) ultimately reduced population size by 21–74%. These simulations illustrate that environmentally amplified maternal influences on early life histories can lower sturgeon population stability and resilience to ever-increasing perturbations.

scholarly journals Rethinking competence in marine life cycles: ontogenetic changes in the settlement response of sand dollar larvae exposed to turbulence

2015 ◽  
Vol 2 (6) ◽  
pp. 150114 ◽  
Author(s):  
Jason Hodin ◽  
Matthew C. Ferner ◽  
Gabriel Ng ◽  
Christopher J. Lowe ◽  
Brian Gaylord
Keyword(s):  
Life Histories ◽  
Immature Stage ◽  
Life Cycles ◽  
Sand Dollar ◽  
Ontogenetic Changes ◽  
Marine Animals ◽  
Settlement And Metamorphosis ◽  
Two Phases ◽  
Pass Through ◽  
Dendraster Excentricus

Complex life cycles have evolved independently numerous times in marine animals as well as in disparate algae. Such life histories typically involve a dispersive immature stage followed by settlement and metamorphosis to an adult stage on the sea floor. One commonality among animals exhibiting transitions of this type is that their larvae pass through a ‘precompetent’ period in which they do not respond to localized settlement cues, before entering a ‘competent’ period, during which cues can induce settlement. Despite the widespread existence of these two phases, relatively little is known about how larvae transition between them. Moreover, recent studies have blurred the distinction between the phases by demonstrating that fluid turbulence can spark precocious activation of competence. Here, we further investigate this phenomenon by exploring how larval interactions with turbulence change across ontogeny, focusing on offspring of the sand dollar Dendraster excentricus (Eschscholtz). Our data indicate that larvae exhibit increased responsiveness to turbulence as they get older. We also demonstrate a likely cost to precocious competence: the resulting juveniles are smaller. Based upon these findings, we outline a new, testable conception of competence that has the potential to reshape our understanding of larval dispersal and connectivity among marine populations.

Annual spawning cycles and planktonic larvae of benthic invertebrates from Passamaquoddy Bay, New Brunswick

1981 ◽  
Vol 59 (3) ◽  
pp. 433-440 ◽  
Author(s):  
T. Lacalli
Keyword(s):  
Benthic Invertebrates ◽  
Diatom Bloom ◽  
Spawning Period ◽  
Polychaete Species ◽  
Lecithotrophic Larva ◽  
Planktonic Larvae ◽  
Passamaquoddy Bay ◽  
Planktotrophic Larvae ◽  
Spawning Periods ◽  
First Time

Periods of larval occurrence are reported for 19 polychaete species and 10 other common planktonic larvae. Egg sizes are given for 29 polychaete species with estimates of spawning period for 14 of these based on studies of the adult worms. Spawning periods are shown to correlate better with larval type (e.g. whether planktotrophic or lecithotrophic) than with the zoogeographic distribution of the adults. Among the planktotrophic larvae, the evidence suggests that some larvae (e.g. polynoid larvae) develop successfully only during the spring diatom bloom, and gamete wastage may result from any substantial mismatch between the diatom bloom and spawning period. The lecithotrophic larva of the tunicate Boltenia ovifera, which spawns in midwinter, is described for the first time.

V - The development of Haliotis Tuberculata , with special reference to organogenesis during torsion

1937 ◽  
Vol 228 (552) ◽  
pp. 219-268 ◽  
Keyword(s):  
Nervous System ◽  
Special Reference ◽  
Larval Development ◽  
Retractor Muscle ◽  
Larval Life ◽  
Free Living ◽  
Larval Stages ◽  
Haliotis Tuberculata ◽  
New Interpretation ◽  
Selection Of

Investigation of the development of Haliotis tuberculata , Linnaeus, was undertaken as a natural sequel to an examination of the bionomics and anatomy of Haliotis (Crofts 1929, p. 159). It is an attempt to elucidate the organogenesis during the changing larval habits, in the hope of adding to the scanty ontogenetical evidence available towards solving the problems of gastropod evolution. Excellent accounts of the embryonic phase, including patiently worked out details of the cleavage and of gastrulation, have been published for Crepidula (Conklin 1897), Patella (Patten 1886; Wilson 1904; and Smith 1935), Trochus (Robert 1902), Physa (Wierzejski 1905), Dentalium (Wilson 1904). The only comprehensive accounts of gastropod larval development already published are of Paludina (Erlanger 1891; Tonniges 1896; Drummond 1902; Andersen 1924) and of Patella (Patten 1886; Smith I935). The accounts of Paludina elucidate the details of development of the coelom and its derivatives. The viviparous habit and consequent loss of free larval life in Paludina , however, make it a very unsuitable example of gastropod development. Evolutionary stages are more likely to be traced from the development of less specialized gastropods, an adequate selection of whose free-living larval stages can be obtained. The larval development of Patel, Acmaea, Trochus and Haliotis has been described, in varying completeness for the different genera. Patten’s work on Patella coerulea (1886) gives a description only of the beginning of organogenesis. After a lapse of fifty years a more detailed account of the development of P. vulgata has been given by Smith (1935). This work gives a new interpretation of the development of the mesoderm, of the muscles and of the nervous system. The dorsal retractor muscle of the larva, which Patten indicated for P. coerula , is shown in P. vulgata to be placed asymmetrically and torsion takes place “ under the action” of this muscle.

scholarly journals Historias de vida y demografía de Physalaemus biligonigerus (Anura: Leptodactylidae) en una charca periurbana del centro de Argentina

2018 ◽  
Vol 66 (2) ◽  
pp. 765
Author(s):  
Ana M. Nicolino ◽  
Clarisa de L. Bionda ◽  
Nancy E. Salas ◽  
Adolfo L. Martino
Keyword(s):  
Life Histories ◽  
Survival Rates ◽  
Reproductive Activity ◽  
Reproductive Rate ◽  
Population Projection ◽  
Current Status ◽  
Leslie Matrix ◽  
Larval Phase ◽  
Net Reproductive Rate ◽  
Larval Stages

Demography and life histories of Physalaemus biligonigerus (Anura: Leptodactylidae) in a peri-urban pond in central Argentina. Knowledge of population dynamics provides information on the recent history, current status, and future trends of a population. Physalaemus biligonigerus is widely distributed in the Neotropics, this anuran has a high and explosive reproductive activity, but its populations seem to be composed of young individuals. The objective of this study was to analyze the population demography of P. biligonigerus in a semipermanent pond in Río Cuarto, Córdoba, Argentina and to carry out a population projection through 30 generations. The age structure was determined from the use of skeletochronology, and a static life table was later made. Fertility and survival rates were calculated for each stage, by which a Leslie Matrix was constructed and the population projection was performed. The projection shows oscillations in the number of individuals but in spite of this, the final tendency of the population is an increase in its size. The highest proportion of survivors occurs in the egg-to-larval stages and the mortality force acts intensively on the larval phase. The net reproductive rate indicates that the population of P. biligonigerus of the study pond is increasing. Rev. Biol. Trop. 66(2): 765-775. Epub 2018 June 01.  

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