The sperm of Matsucoccus feytaudi (Insecta, Coccoidea): Can the microtubular bundle be considered as a true flagellum?

Paoli, Francesco; Roversi, Pio Federico; Benassai, Daniele; Squarcini, Michele; Mercati, David; Dallai, Romano

doi:10.1016/j.asd.2014.11.005

Cited by 9 publications

(2 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In both scale insects (Hemiptera: Coccoidea) and fungus gnats (Diptera), which share the features of unusual centrioles and PGE, centrioles have lost their nine‐fold symmetry and become very large with up to thousands of microtubules (Figs and a,b) (Phillips, ; Robison, ; Callaini et al ., ; Paoli et al ., ). These ‘giant’ centrioles are not found in every cell, though.…”

Section: Ultraconserved or Ultravariablementioning

confidence: 99%

Evolutionary problems in centrosome and centriole biology

Ross

Normark

2015

J of Evolutionary Biology

View full text Add to dashboard Cite

Centrosomes have been an enigma to evolutionary biologists. Either they have been the subject of ill‐founded speculation or they have been ignored. Here, we highlight evolutionary paradoxes and problems of centrosome and centriole evolution and seek to understand them in the light of recent advances in centrosome biology. Most evolutionary accounts of centrosome evolution have been based on the hypothesis that centrosomes are replicators, independent of the nucleus and cytoplasm. It is now clear, however, that this hypothesis is not tenable. Instead, centrosomes are formed de novo each cell division, with the presence of an old centrosome regulating, but not essential for, the assembly of a new one. Centrosomes are the microtubule‐organizing centres of cells. They can potentially affect sensory and motor characters (as the basal body of cilia), as well as the movements of chromosomes during cell division. This latter role does not seem essential, however, except in male meiosis, and the reasons for this remain unclear. Although the centrosome is absent in some taxa, when it is present, its structure is extraordinarily conserved: in most taxa across eukaryotes, it does not appear to evolve at all. And yet a few insect groups display spectacular hypertrophy of the centrioles. We discuss how this might relate to the unusual reproductive system found in these insects. Finally, we discuss why the fate of centrosomes in sperm and early embryos might differ between different groups of animals.

show abstract

Section: Ultraconserved or Ultravariablementioning

confidence: 99%

Evolutionary problems in centrosome and centriole biology

Ross

Normark

2015

J of Evolutionary Biology

View full text Add to dashboard Cite

show abstract

“…Interestingly, the sperm of the highly specialized sternorrhynch subgroup Coccoidea have lost a conventional flagellar axoneme, and regained their motility through a flagellum produced by an acentriolar microtubule‐organizing centre (Paoli et al. ,b).…”

Section: Discussionmentioning

confidence: 99%

The evolution of insect sperm − an unusual character system in a megadiverse group

Gottardo

Dallai

Mercati

et al. 2016

J Zool Syst Evol Res

Self Cite

View full text Add to dashboard Cite

Spermatozoa provide an unusual character system, with a limited number of components organized in a single cell. Similar spermatozoa occur in groups widely separated in the phylogenetic tree of Metazoa. Nevertheless, the character system contains phylogenetic information. Hexapoda have acquired spermatophores along with the switch from aquatic to terrestrial habitats, and related to this, a multitude of different sperm types. The aim of this study is a formal evaluation of the phylogenetic information content of spermatozoa. For the first time, sperm characters are coded for formal phylogenetic analyses. Different approaches are used and compared. Mainly due to a high level of homoplasy, the evaluation of sperm characters alone is insufficient for a reconstruction of the phylogeny of the group. Yet, a reliable reconstruction of the evolution of insect sperm is possible when character transformations are assessed using a phylogeny based on extensive molecular data. Important changes took place in the early evolution of Hexapoda. Sperm characters support some major clades (e.g. Hexapoda, Dicondylia, Polyneoptera, Psocodea), but important steps in the evolution are not reflected by transformations of spermatozoa, notably the rise of Pterygota or Holometabola. Important innovations are the formation of mitochondrial derivatives and the acquisition of accessory microtubules. Some features are conservative, whereas others evolved rapidly (e.g. presence or absence of the acrosome vesicle). Some groups are conservative in their sperm features (e.g. Odonata, Heteroptera), whereas the evolution of spermatozoa was distinctly accelerated in others (e.g. Ephemeroptera). The rate of evolution can change drastically in closely related groups. Profound changes in the morphologically uniform Zoraptera underline that sperm evolution can follow a pattern very different from the general somatic morphology. The mode of character reconstruction preferred here will be useful for the evaluation of specialized morphological character systems and strengthen the concept of evolutionary morphology.

show abstract