The evolution of larval developmental mode: insights from hybrids between species with obligately and facultatively planktotrophic larvae

2015 ◽  
Vol 17 (5) ◽  
pp. 278-288 ◽  
Author(s):  
Anne Frances Armstrong ◽  
Harilaos A. Lessios
Keyword(s):  
Developmental Mode ◽  
Planktotrophic Larvae

scholarly journals Plasticity and Artificial Selection for Developmental Mode in a Poecilogonous Sea Slug

2020 ◽  
Author(s):  
Serena A. Caplins
Keyword(s):  
Intraspecific Variation ◽  
High Salinity ◽  
Reaction Norm ◽  
Offspring Size ◽  
Response To Selection ◽  
Sea Slug ◽  
Developmental Mode ◽  
Low Salinity ◽  
Selection For ◽  
Planktotrophic Larvae

AbstractDevelopmental mode describes the means by which larvae are provisioned with the nutrients they need to proceed through development and typically results in a trade-off between offspring size and number. The sacoglossan sea slug Alderia willowi exhibits intraspecific variation for developmental mode (= poecilogony) that is environmentally modulated with populations producing more yolk-feeding (lecithotrophic) larvae during the summer, and more planktonic feeding (planktotrophic) larvae in the winter. I found significant family level variation in the reaction norms between 17 maternal families of A. willowi when reared in low (16 ppt) versus high (32 ppt) salinity. I documented a significant response to selection for lecithotrophic larvae, the proportion of which increased 32% after three generations of selection in high salinity, and 18% after 2 generations in low salinity (realized heritability: 0.365 ± 0.024). The slope of the reaction norm was maintained following one generation of selection for lecithotrophy and one generation of selfing. The rapid response to selection favoring one developmental mode may speak to the rarity of intraspecific variation for developmental mode, which could fix for one mode over another much more readily than has generally been assumed from studies of less plastic organisms.

The missing links: larval and post-larval development of the ascoglossan opisthobranch Elysia viridis

2000 ◽  
Vol 80 (6) ◽  
pp. 1087-1094 ◽  
Author(s):  
Cynthia D. Trowbridge
Keyword(s):  
Larval Development ◽  
Growth Rates ◽  
Shell Length ◽  
Larval Growth ◽  
Model Organism ◽  
Larval Life ◽  
Codium Fragile ◽  
Planktotrophic Larvae ◽  
Algal Diet ◽  
Better Than

The stenophagous ascoglossan (=sacoglossan) opisthobranch Elysia viridis has long been a model organism for the study of endosymbiosis or kleptoplasty as well as one of the few herbivores to consume the introduced green macroalga Codium fragile on European shores. Larval and post-larval dynamics of the ascoglossan were investigated. Planktotrophic larvae of E. viridis grew at 5–10 μm d−1 (shell length) at 15°C on a unicellular algal diet (the cryptophyte Rhodomonas baltica); larvae became competent one month post-hatching. Effective feeding and chloroplast acquisition typically started within 2–3 d of metamorphosis. Slugs grew about 8 mm in the first month of post-larval life. During this period, juveniles held in the light did not grow faster or survive better than conspecifics held in the dark; thus, functional kleptoplasty did not occur during first three weeks of benthic life. While larval growth rates and the nature of metamorphic cues are consistent with those of many other opisthobranch species with planktotrophic larvae, measures of post-larval growth—particularly as it pertains to kleptoplasty—is a new contribution to opisthobranch biology.

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.

scholarly journals Geographic contingency, not species sorting, dominates macroevolutionary dynamics in an extinct clade of neogastropods (Volutospina; Volutidae)

Paleobiology ◽  
2021 ◽  
pp. 1-15
Author(s):  
Dana S. Friend ◽  
Brendan M. Anderson ◽  
Warren D. Allmon
Keyword(s):  
Middle Eocene ◽  
Ecological Factors ◽  
Geographic Range ◽  
Late Eocene ◽  
Range Size ◽  
Species Sorting ◽  
Extinction Rates ◽  
Geographic Range Size ◽  
Speciation Rates ◽  
Planktotrophic Larvae

Abstract Rates of speciation and extinction are often linked to many ecological factors, traits (emergent and nonemergent) such as environmental tolerance, body size, feeding type, and geographic range. Marine gastropods in particular have been used to examine the role of larval dispersal in speciation. However, relatively few studies have been conducted placing larval modes in species-level phylogenetic context. Those that have, have not incorporated fossil data, while landmark macroevolutionary studies on fossil clades have not considered both phylogenetic context and net speciation (speciation–extinction) rates. This study utilizes Eocene volutid Volutospina species from the U.S. Gulf Coastal Plain and the Hampshire Basin, U.K., to explore the relationships among larval mode, geographic range, and duration. Based on the phylogeny of these Volutospina, we calculated speciation and extinction rates in order to compare the macroevolutionary effects of larval mode. Species with planktotrophic larvae had a median duration of 9.7 Myr, which compared significantly to 4.7 Myr for those with non-planktotrophic larvae. Larval mode did not significantly factor into geographic-range size, but U.S. and U.K. species do differ, indicating a locality-specific component to maximum geographic-range size. Non-planktotrophs (NPTs)were absent among the Volutospina species during the Paleocene–early Eocene. The relative proportions of NPTs increased in the early middle Eocene, and the late Eocene was characterized by disappearance of planktotrophs (PTs). The pattern of observed lineage diversity shows an increasing preponderance of NPTs; however, this is clearly driven by a dramatic extinction of PTs, rather than higher NPT speciation rates during the late Eocene. This study adds nuance to paleontology's understanding of the macroevolutionary consequences of larval mode.

Thyroid hormones determine developmental mode in sand dollars (Echinodermata: Echinoidea)

2004 ◽  
Vol 6 (6) ◽  
pp. 382-392 ◽  
Author(s):  
Andreas Heyland ◽  
Adam M. Reitzel ◽  
Jason Hodin
Keyword(s):  
Thyroid Hormones ◽  
Developmental Mode ◽  
Sand Dollars

scholarly journals Do differences in developmental mode shape the potential for local adaptation?

Ecology ◽  
2020 ◽  
Vol 101 (3) ◽  
Author(s):  
L. L. Jupe ◽  
D. T. Bilton ◽  
A. M. Knights
Keyword(s):  
Local Adaptation ◽  
Mode Shape ◽  
Developmental Mode

Analysis of the juvenile shell of Lingula anatina (Brachiopoda: Linguliformea) provides insight into the evolution of life cycles of fossil brachiopods

Paleobiology ◽  
2020 ◽  
pp. 1-15
Author(s):  
Anna A. Madison ◽  
Tatyana V. Kuzmina ◽  
Elena N. Temereva
Keyword(s):  
Life Cycle ◽  
Anterior Margin ◽  
The Philippines ◽  
Life Cycles ◽  
Published Data ◽  
Egg Envelope ◽  
Evolution Of Life ◽  
The Republic ◽  
Planktotrophic Larvae ◽  
Insight Into

Abstract Inferences on the development and morphology of extinct brachiopods must be informed by the ontogeny and shell ornamentation of extant brachiopods. Although the adult shells of extant brachiopods are well studied, detailed descriptions of the embryonic and juvenile shells of extant lingulides are lacking. Here, we describe in detail the shells of juveniles of Lingula anatina Lamarck, 1801 from Vietnam and the Republic of the Philippines. The following previously unknown properties of the lingulide shell are described: (1) a distinct border between the protegulum and the brephic shell; (2) drapes that develop on both the protegulum and brephic shell; and (3) the notched anterior margin of the brephic shell. The drapes and cogs on the brephic shell may be caused by the formation of setal follicles during the planktonic stage. Specimens of L. anatina from the Philippines have larger brephic shells than those from Vietnam, probably because the former have a longer planktonic stage. Based on comparisons of the first-formed shells of extant brachiopods with published data on fossil brachiopods, we suggest that the life cycle of extant lingulides, in which planktotrophic juveniles with a shell hatch from the egg envelope, is the most evolutionarily advanced brachiopod life cycle and appeared in the early Silurian. We suggest criteria for determining the type of life cycle based on the structure of the first-formed shell of brachiopods. Finally, we consider hypothetical scenarios of life cycles of fossil brachiopods, including true planktotrophic larvae in the Cambrian linguliforms.

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