The little dragon sculpinBlepsias cirrhosus, another case of internal gametic association and external fertilization

1991 ◽  
Vol 37 (4) ◽  
pp. 391-394 ◽  
Author(s):  
Hiroyuki Munehara ◽  
Kazunori Takano ◽  
Yasunori Koya
Keyword(s):  
External Fertilization ◽  
Gametic Association

Internal Gametic Association and External Fertilization in the Elkhorn Sculpin, Alcichthys alcicornis

Copeia ◽  
1989 ◽  
Vol 1989 (3) ◽  
pp. 673 ◽  
Author(s):  
Hiroyuki Munehara ◽  
Kazunori Takano ◽  
Yasunori Koya
Keyword(s):  
External Fertilization ◽  
Gametic Association

scholarly journals Sexual selection after gamete release in broadcast spawning invertebrates

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200069 ◽  
Author(s):  
Jonathan P. Evans ◽  
Rowan A. Lymbery
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Sperm Competition ◽  
Sexual Conflict ◽  
Gamete Release ◽  
Theme Issue ◽  
Animal Kingdom ◽  
External Fertilization ◽  
Broadcast Spawning ◽  
Males And Females

Broadcast spawning invertebrates offer highly tractable models for evaluating sperm competition, gamete-level mate choice and sexual conflict. By displaying the ancestral mating strategy of external fertilization, where sexual selection is constrained to act after gamete release, broadcast spawners also offer potential evolutionary insights into the cascade of events that led to sexual reproduction in more ‘derived’ groups (including humans). Moreover, the dynamic reproductive conditions faced by these animals mean that the strength and direction of sexual selection on both males and females can vary considerably. These attributes make broadcast spawning invertebrate systems uniquely suited to testing, extending, and sometimes challenging classic and contemporary ideas in sperm competition, many of which were first captured in Parker's seminal papers on the topic. Here, we provide a synthesis outlining progress in these fields, and highlight the burgeoning potential for broadcast spawners to provide both evolutionary and mechanistic understanding into gamete-level sexual selection more broadly across the animal kingdom. This article is part of the theme issue ‘Fifty years of sperm competition’.

External Fertilization

2020 ◽  
pp. 1-7
Author(s):  
Megha Das ◽  
Nitesh Kumar Mishra ◽  
Sanjeev Kumar Yadav
Keyword(s):  
External Fertilization

scholarly journals Biological Consequences of Topography on Wave-swept Rocky Shores: I. Enhancement of External Fertilization

1992 ◽  
Vol 183 (2) ◽  
pp. 220-232 ◽  
Author(s):  
M. Denny ◽  
J. Dairiki ◽  
S. Distefano
Keyword(s):  
Rocky Shores ◽  
External Fertilization

A review of the early life history of zebra mussels (Dreissena polymorpha): comparisons with marine bivalves

1994 ◽  
Vol 72 (7) ◽  
pp. 1169-1179 ◽  
Author(s):  
Josef Daniel Ackerman ◽  
Blair Sim ◽  
S. Jerrine Nichols ◽  
Renata Claudi
Keyword(s):  
Life History ◽  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Early Life History ◽  
Zebra Mussels ◽  
Larval Shell ◽  
Planktonic Larva ◽  
External Fertilization ◽  
Marine Bivalves ◽  
History Of

The ecological and economic impacts of the introduced zebra mussel (Dreissena polymorpha (Pallas)) have been due in part to a life history that is conserved with marine bivalves but unique among the indigenous freshwater fauna. There are a number of life history events in D. polymorpha that follow external fertilization and embryology. The first is a brief trochophore stage. The development of a velum and secretion of a larval shell lead to a D-shaped veliger, which is the first recognizable planktonic larva. Later a second larval shell is secreted and this veliconcha is the last obligate free-swimming veliger. Conversely, the last larval stage, the pediveliger, can either swim using its velum or crawl using its foot. Pediveligers select substrates on which they "settle" by secreting byssal threads and undergo metamorphosis to become plantigrade mussels. The secretion of the adult shell and change in growth axis lead to the convergent heteromyarian shape. Zebra mussels produce byssal threads as adults, but these attachments may be broken, enabling the mussels to translocate to new areas. The recognition of these life history features will lead to a better understanding of zebra mussel biology. In summary, life history stages of zebra mussels are similar to those of marine bivalves and should be identified morphologically rather than on the basis of size.

scholarly journals Sex allocation in haplodiploids is mediated by egg size: evidence in the spider mite Tetranychus urticae Koch

2010 ◽  
Vol 278 (1708) ◽  
pp. 1054-1063 ◽  
Author(s):  
Emilie Macke ◽  
Sara Magalhães ◽  
Hong Do-Thi Khan ◽  
Anthony Luciano ◽  
Adrien Frantz ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tetranychus Urticae ◽  
Egg Size ◽  
Spider Mite ◽  
Sex Ratios ◽  
Size Difference ◽  
Adult Size ◽  
External Fertilization ◽  
Offspring Sex Ratio ◽  
Egg Provisioning

Haplodiploid species display extraordinary sex ratios. However, a differential investment in male and female offspring might also be achieved by a differential provisioning of eggs, as observed in birds and lizards. We investigated this hypothesis in the haplodiploid spider mite Tetranychus urticae , which displays highly female-biased sex ratios. We show that egg size significantly determines not only larval size, juvenile survival and adult size, but also fertilization probability, as in marine invertebrates with external fertilization, so that female (fertilized) eggs are significantly larger than male (unfertilized) eggs. Moreover, females with on average larger eggs before fertilization produce a more female-biased sex ratio afterwards. Egg size thus mediates sex-specific egg provisioning, sex and offspring sex ratio. Finally, sex-specific egg provisioning has another major consequence: male eggs produced by mated mothers are smaller than male eggs produced by virgins, and this size difference persists in adults. Virgin females might thus have a (male) fitness advantage over mated females.

Intercropping fava bean with broccoli can improve soil properties while maintaining crop production under Mediterranean conditions

2020 ◽  
Author(s):  
Mariano Marcos-Pérez ◽  
Virginia Sánchez-Navarro ◽  
Raúl Zornoza
Keyword(s):  
Soil Fertility ◽  
Soil Properties ◽  
Soil Quality ◽  
Crop Production ◽  
Management Practices ◽  
Climatic Conditions ◽  
Crop Diversification ◽  
Crop Species ◽  
External Fertilization ◽  
Fava Bean

<p>Including legumes in intercropping systems may be regarded as a sustainable way to improve soil quality, fertility and land productivity, mostly due to facilitation processes and high rhizospheric activity which can mobilize soil nutrients for plants. Improvements in production and soil quality depend on inherent soil properties, climatic conditions, adopted management practices and fertilization, among others. The aim of this study was to assess the effect of the association between broccoli (Brassica oleracea var italica) and fava bean (Vicia fava) grown under different intercropping patterns on crop production, soil organic carbon (SOC), total nitrogen (Nt), soil aggregate stability (SAS) and soil fertility, compared to a broccoli monocrop. We defined a randomised block field experiment with three replications assessing the effect of monocropping, row 1:1 intercropping, row 2:1 intercropping and mix intercropping, with 30% reduction in fertilization in intercropped systems compared to monocrop. Soil sampling took place at harvest in February 2019. Results showed that the broccoli-fava bean intercropping significantly increased the general land production, with similar broccoli yield of 20000 kg ha<sup>-1 </sup>in all treatments, plus 8000 kg ha<sup>-1</sup> coming from fava bean. Crop diversification and fava bean cultivation even in monocrop significantly increased SOC and Nt compared to broccoli monocrop. SOC and Nt were 1.06% and 0.09%, respectively, for broccoli monocrop, while they had average values of 1.29% and 0.12%, respectively for the intercropped systems. SAS was also significantly affected by crop diversification, with increases in the proportion of the macroaggregates (size >2 mm) with intercropping. Broccoli monocrop showed an average proportion of these macroaggregates of 9.19%, while they increased up to 17.51% in intercropped systems. CEC was not significantly affected by intercropping SAS showing almost same percentage of aggregates independently of the treatment. Available P significantly increased in intercropped systems, likely due to increased microbial activity with the simultaneous growth of the two crop species. However, no significant effect of intercropping was observed with any other nutrient (Ca, Mg, K, Mn, Cu, Fe, Zn and B), suggesting that microbial communities activated by the crop association are highly related to P mobilization but not so intensively involved in other nutrients. Thus, intercropping systems like broccoli-fava bean association can be regarded as a viable alternative for sustainable crop production while increasing soil fertility despite reducing the addition of external fertilization. However, more crop cycles are needed to confirm this trend.</p>

Sign in / Sign up

Export Citation Format

Share Document