Caste development and sex ratio of the Ryukyu drywood termite Neotermes sugioi and its potential mechanisms

Sex allocation is one of the most studied traits in evolutionary biology because its theoretical predictions match the empirical data. Here, using the Ryukyu dry-wood termite Neotermes sugioi, we investigated several factors that could bias the sex allocation in three populations (Okinawa, Ishigaki/Iriomote, and Yonaguni). Our survey showed that there were more queen-only colonies than king-only colonies in these populations, suggesting a longer lifespan of the queens than that of the kings. In this condition, sex-asymmetric reproductive value (SRV) theory predicts female bias, because even after the short-lived kings die, the long-lived queens can continue reproduction with their sons. However, sex allocation in this species seemed to be biased toward males. Furthermore, we examined the possibility of intrasexual competition among siblings (ICS). If ICS is the cause of the bias, the allocation is expected to change depending on the total investment in sexual offspring. However, the biomass of both male and female alates increased linearly with the increase in the total biomass of the alates in these populations. Thus, neither the SRV nor the ICS theory could explain the male-biased sex ratio of N. sugioi. On the basis of these results, we discuss the remaining possibilities in this species.

Citizenship as a caste marker: How persons experience cross-national inequality

Extrapolating a recent conceptualization of caste from India to the global level, this article argues that persons experience cross-national inequalities via their citizenship as a caste marker. Rather than imagine castes as features of the fixed pre-modern Hindu social order, the article posits that castes are variable modern ascriptive social hierarchies subject to contestation and change in which economic and social distinctions are maintained through physical and symbolic violence. The study shows how, globally, nation-states exert physical and symbolic violence to normalize cross-national inequalities instituting a global citizenship-based caste order. This approach recognizes the importance of both global material relations emphasized by world-systems approaches and of symbolic structures central to global institutionalist approaches. The study also underscores persons’ positions and experiences confronting nation-states’ might. Power struggles concentrated on nation-states result in variability of global relations’ mutually reinforcing material and symbolic dimensions. The author uses caste features that appear ‘essential’ (i.e. ascriptive social closure, ‘ethnic,’ ‘religious,’ and ‘purity’ distinctions) as heuristics for identifying possible locations of caste construction and contestation, and identifies citizenship rules, nation-states’ territorial nature, nationalism, and visa, border, and naturalization rituals as such caste development sites. Vulnerable groups (stateless persons, refugees, migrants) both challenge the citizenship caste order and experience viscerally its physical and symbolic violence.

Model Residential School Education to Scheduled Caste Pupils in Kerala

There are about forty lakh scheduled caste people in Kerala. Most of them are poor and daily wage workers. The socio-economic backwardness of scheduled caste people is a historically determined outcome of a caste system in India. Education is the only way for them to get out of this historical whirlwind of economic deprivation, denial of rights and social exclusion. The Government of India passed The Right to Education Act in 2010 and it ensures “free and compulsory education” for all children aged 6 to 14. The government of Kerala has introduced many innovative programs to provide education for scheduled caste pupils in the state. “Model Residential School” owned and managed by the Scheduled Caste Development Department of The Government of Kerala, is one of such successful initiatives. Model Residential Schools take special care to cater to the educational needs of the underprivileged children and help them to attain quality education. In this article, the investigators explore the role played by the model residential schools in the educational development of scheduled caste pupils in Kerala and particularly in solving the burning issue of a high rate of dropouts among scheduled caste pupils.

Endocuticle is involved in caste differentiation of the lower termite

Caste differentiation in termites is one of the most conspicuous examples of facultative polyphenism in animals. It is clear that specific cuticular formation occurs in hard exocuticles during caste differentiation. However, the developmental pattern of the soft endocuticle in the differentiation pathways of castes is unknown. To reveal whether the endocuticle is involved in caste differentiation, we compared the exocuticle and endocuticle thickness of individuals in 2 pathways (nymph line and worker line) of caste differentiation in the termite Reticulitermes aculabialis. The endocuticle protein genes were identified by transcriptome analysis and the expression patterns of these genes were confirmed in caste differentiation. We found that the endocuticle structure showed dynamic changes in 2 pathways, and the first difference in endocuticle structure occurred after larvae differentiation bifurcated into workers and nymphs. The thinning of the endocuticle was a significant event from nymphs developing into alates with the thickest exocuticle and thinnest endocuticle. The thickest endocuticle layers were found in the heads of the workers and the ultrastructure of the endocuticle in the heads was more complex than that in the thorax–abdomens. Six endocuticle protein genes were identified and annotated as endocuticle structural glycoproteins SgAbd-2, SgAbd-9, and Abd-5. The expression levels of endocuticle protein genes changed dramatically during caste development and the expression levels in neotenic reproductives (secondary reproductives) were significantly higher than those in alates (primary reproductives). These results reveal the roles of endocuticles in caste differentiation and adaptation to the environment.

Evidence of transfer of miRNAs from the diet to the blood still inconclusive

MicroRNAs (miRNAs) are short, non-coding, single-strand RNA molecules that act as regulators of gene expression in plants and animals. In 2012, the first evidence was found that plant miRNAs could enter the bloodstream through the digestive tract. Since then, there has been an ongoing discussion about whether miRNAs from the diet are transferred to blood, accumulate in tissues, and regulate gene expression. Different research groups have tried to replicate these findings, using both plant and animal sources. Here, we review the evidence for and against the transfer of diet-derived miRNAs from plants, meat, milk and exosome and their assimilation and putative molecular regulation role in the consuming organism. Some groups using both miRNAs from plant and animal sources have claimed success, whereas others have not shown transfer. In spite of the biological barriers that may limit miRNA transference, several diet-derived miRNAs can transfer into the circulating system and targets genes for transcription regulation, which adds arguments that miRNAs can be absorbed from the diet and target specific genes by regulating their expression. However, many other studies show that cross-kingdom transfer of exogenous miRNAs appears to be insignificant and not biologically relevant. The main source of controversy in plant studies is the lack of reproducibility of the findings. For meat-derived miRNAs, studies concluded that the miRNAs can survive the cooking process; nevertheless, our evidence shows that the bovine miRNAs are not transferred to human bloodstream. The most important contributions and promising evidence in this controversial field is the transference of milk miRNAs in exosomes and the finding that plant miRNAs in beebread regulate honeybee caste development, and cause similar changes when fed to Drosophila. MiRNAs encapsulated in exosomes ensure their stability and resistance in the harsh conditions presented in milk, bloodstream, and gastrointestinaltract to reinforce the idea of transference. Regardless of the model organism, the idea of source of miRNAs, or the approach—bioinformatics or in vivo—the issue of transfer of miRNAs from the diet remains in doubt. Our understanding of the cross-kingdom talk of miRNAs needs more research to study the transfer of “xenomiRs” from different food sources to complement and expand what we know so far regarding the interspecies transfer of miRNAs.