Partial table of contents: Annelida-Clitellata (B Christensen) Tardigrada (R Bertolani) Arthropoda-Insecta (J Muthukrishnan) Pentastomida (J Riley) Bryozoa Entoprocta (C Nielsen) Brachiopoda (S Chuang) Chaetognatha (A Alvari?o) Echinodermata: Asexual Propagation (P Mladenov & R Burke) Cephalochordata (J Azariah) Indexes

The hologenome concept of evolution relies on ensuring the continuity of partnerships between holobiont generations. Accordingly, both host and symbiont genomes must be transmitted with accuracy from one generation to the next. The precise modes of vertical transmission of host genomes are well understood and need not be discussed here. However, in recent years, it has become clear that microbial symbionts can also be transmitted from parent to offspring by a variety of methods. In an insightful review on transmission of microbial symbionts, Bright and Bulgheresi (Nat Rev Microbiol 8:218–230, 2010) divide the modes for maintaining symbionts faithfully between generations into two categories, vertical—from parent and horizontal—from environment, while correctly acknowledging that mixed modes also occur. We would like to take this approach one step further by suggesting that numerous mixed and intermediate cases, many of which are discussed in this chapter, best describe the large variety in modes of transmission which are known at present to reconstitute plant and animal holobionts. It is this continuum of modes of transmission from vertical to horizontal that makes it impractical to often place them in any specific category.

Asexual propagation and reproductive strategies

Microbiotas are Transmitted Between Holobiont Generations

.................................................................................................................................................. 3 Acknowledgements ................................................................................................................................. 4 Declaration of originality ........................................................................................................................ 5 Table of contents ..................................................................................................................................... 6 Figures and tables ................................................................................................................................. 10 Data accessibility .................................................................................................................................. 14 Abbreviations ........................................................................................................................................ 15 Chapter 1: Introduction ......................................................................................................................... 17 Rotifera ....................................................................................................................................... 18 Defining asexual species ............................................................................................................. 19 Ancient asexuality ...................................................................................................................... 20 Bdelloid rotifers ..................................................................................................................... 20 Oribatid mites (Acari: Arthropoda) ....................................................................................... 21 Darwinulid ostracods (Ostracoda: Arthropoda)..................................................................... 21 Timema stick insects (Pterygota: Arthropoda) ...................................................................... 22 Root knot nematodes (Secernentea: Nematoda) .................................................................... 22 Taxonomy ................................................................................................................................... 22 Molecular techniques and their limitations: Issues with using one locus instead of many ... 24 DNA barcoding ..................................................................................................................... 24 DNA taxonomy ..................................................................................................................... 26 Thesis structure ........................................................................................................................... 27 Summary of aims ........................................................................................................................ 29 Chapter 2: The widely used small subunit 18S rDNA molecule greatly underestimates true diversity in biodiversity surveys of the meiofauna .................................................................................................. 31 Abstract ....................................................................................................................................... 3

background

The consequences of life without sex: an examination into taxonomy and evolution of the anciently asexual bdelloid rotifers

The class Demospongiae comprises sponges, whose skeleton consists of either spongin fibers only or spongin fibers in combination with siliceous spicules (usually, macro- and microscleres). Macroscleres are mostly monoaxial and tetraxial, while microscleres are very diverse – monoaxial or polyaxial, often in complicated shape. The axial filament resides in a triangular or hexangular cavity. Fibrillar collagen has been noted in all the Demospongiae. In some groups, the reduced spicular skeleton is compensated for by a complex organic one; in some other groups, there are no skeletal elements whatsoever. In several small Demospongiae groups, a hyper-calcified basal skeleton develops in addition to other skeletal elements (Sollas 1885).

Development of sponges from the class Demospongiae Sollas, 1885

. Mahmoud HHA, Sastranegara MH, Kusmintarsih ES. 2020. Short Communication: The lifecycle of Neocaridina denticulata and N. palmata in aquariums. Biodiversitas 21: 2396-2402. The study on the life cycle of Neocaridina spp. is important because it plays a major role in the economy and trade between countries. However, there is a lack of sufficient studies on this particular topic. One of the factors that influence Neocaridina spp. life production is its life cycle and the associated water parameters. The objectives of this study were to conduct, observe, and record the life cycle of Neocaridina denticulata and N. palmata and the associated with water parameters (temperature, pH, ammonia, nitrite, and oxygen) in the aquarium. The results showed that there was no difference in the life cycle stages between the two shrimp species. Both species reached the first sexual maturity stage of the life cycle at 75 days, with the maximum body length of the mature shrimp ranging from 2.30-3.00 cm. The eggs became larvae in 15 days, larvae reached the juvenile stage after 60 days, and the juvenile became mature in 15 days. The number of eggs was influenced by the body size of the female shrimps; smaller females produced fewer eggs. Optimal water quality varies by species and must be monitored to ensure growth and survival. The temperature range in this study was 25-28°C and the pH was 6.5-8.0. The ammonia level was in the range between 1.21 and1.72 mg/L, the nitrate was between 0.06 and 7.91 mg/L, and the oxygen was around 5.5-7.9 mg/L. All of the water quality parameters in this study are within the acceptable range for Neocardina cultivation.

result

/pdf/short-communication-the-lifecycle-of-neocaridina-denticulata-53z8o3azba.pdf

Short Communication: The lifecycle of Neocaridina denticulata and N. palmata in aquariums

Hermaphrodite enchytraeids usually breed sexually, but a few species can also multiply asexually by fragmentation (architomy). These species can alternate sexual breeding with asexual breeding by fragmentation. In Hungary, a Marionina species was found in the botanical garden of University of Szeged in 209, which is also able to reproduce asexually by architomy. No mature specimens of this species have been found so far. Fragmentation was observed rarely in these individuals and a strategy comparable to other fragmenting species is not known.

/pdf/first-record-of-reproduction-by-fragmentation-in-the-genus-3uytr9quk5.pdf

Asexual propagation and reproductive strategies

Citations

Microbiotas are Transmitted Between Holobiont Generations

The consequences of life without sex: an examination into taxonomy and evolution of the anciently asexual bdelloid rotifers

Development of sponges from the class Demospongiae Sollas, 1885

Short Communication: The lifecycle of Neocaridina denticulata and N. palmata in aquariums

First record of reproduction by fragmentation in the genus Marionina

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