Density Dependence of Sexual Reproduction in Enchytraeus bigeminus (Enchytraeidae)

Oikos ◽  
1973 ◽  
Vol 24 (2) ◽  
pp. 287 ◽  
Author(s):  
Bent Christensen
Keyword(s):  
Density Dependence ◽  
Sexual Reproduction

scholarly journals Sexual reproduction in the fungal foliar pathogen Zymoseptoria tritici is driven by antagonistic density-dependence mechanisms

2018 ◽  
Author(s):  
Frédéric Suffert ◽  
Ghislain Delestre ◽  
Sandrine Gélisse
Keyword(s):  
Density Dependence ◽  
Sexual Reproduction ◽  
Vertical Position ◽  
Ecological Knowledge ◽  
Zymoseptoria Tritici ◽  
Asexual Multiplication ◽  
Ecological Mechanisms ◽  
Evolutionary Consequences ◽  
Foliar Pathogens ◽  
Host Tissues

AbstractThis study provides empirical evidence for antagonistic density-dependence mechanisms driving sexual reproduction in the wheat fungal pathogen Zymoseptoria tritici. Biparental crosses with 12 increasing inoculum concentrations, in controlled conditions, showed that sexual reproduction in Z. tritici was impacted by an Allee effect due to mate limitation and a competition with asexual multiplication for resource allocation. We found that asexual multiplication was itself affected by competition for host resources between the two parental isolates, as illustrated by the decrease in asexual fruiting body density and sporulation intensity observed with increasing lesion density. Consistent with these results for controlled co-inoculation, we found that the intensity of sexual reproduction varied with both cropping period and the vertical position of the host tissues in the field. An optimal lesion density maximizing offspring (ascospores) number was established, and its eco-evolutionary consequences are considered here. Two ecological mechanisms may be involved: competition for resources between the two modes of reproduction (decrease in the host resources available for sexual reproduction due to their prior use in asexual multiplication), and competitive disequilibrium between the two parental isolates, due to differential interaction dynamics with the host, for example, leading to an imbalance between mating types. Conceptual models based on these results suggest that sexual reproduction plays a key role in the evolution of pathogenicity traits, including virulence and aggressiveness. Ecological knowledge about the determinants of sexual reproduction in Z. tritici may, therefore, open up new perspectives for the management of other fungal foliar pathogens with dual modes of reproduction.

Life cycle of Spirogyra decimina var. juergensii (Kütz.) O.V. Petlovany from Lake Baikal

2018 ◽  
pp. 1-7
Author(s):  
Ekaterina A. Volkova
Keyword(s):  
Life Cycle ◽  
Sexual Reproduction ◽  
Lake Baikal

Identification of Spirogyra species is based on the morphology of the fertile specimens. This work provides characteristics of growth and the time of reproduction of Spirogyra decimina var. juergensii in Lake Baikal and describes sexual reproduction and conditions for germination of new filaments of this species isolated from the lake.

Sexual Reproduction of a Red Tide Dinoflagellate Gymnodinium mikimotoi

1994 ◽  
Vol 60 (1) ◽  
pp. 125-126 ◽  
Author(s):  
Akira Ouchi ◽  
Satoshi Aida ◽  
Takuji Uchida ◽  
Tsuneo Honjo
Keyword(s):  
Sexual Reproduction ◽  
Red Tide

Definitions and concepts of reproductive biology of diatoms (terminological glossary)

2017 ◽  
Vol 51 ◽  
pp. 71-105 ◽  
Author(s):  
N. A. Davidovich
Keyword(s):  
Mating System ◽  
Sexual Reproduction ◽  
Reproductive Biology ◽  
World Literature ◽  
Russian Literature ◽  
Life Cycles ◽  
Transfer Of Knowledge ◽  
Research Experience ◽  
Key Terms

The absence of a conceptual terminology, sufficiently developed and widely accepted in the Russian literature, significantly hinders progress in the field of reproductive biology of diatoms, restricts communication and debate, prevents training and transfer of knowledge. The present work is an attempt, based on world literature and our own research experience, to summarize, systematize, add, and clarify the existing terms, concepts and definitions related to research which are focused on sex and sexual reproduction in diatoms. A glossary of key terms (more than 200, including synonyms) is provided. Terms refer to diatom reproductive biology, life cycles, fertilization, mating system, gender (including inheritance and determination of sex, as well as inheritance associated with sex). Contradictions between possible interpretations of certain terms are briefly discussed.

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