Queens close sperm-gates of eggs for asexual reproduction in termites

Dissertação de Mestrado Integrado em Arquitectura, apresentada ao Departamento de Arquitectura da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A presente dissertação de mestrado pretende desenvolver uma rede de percursos interpretativos no Município de Condeixa-a-Nova, destinada a mobilidades lentas - preferencialmente a ciclável - numa tentativa de estimular a aproximação da comunidade residente e visitante ao Território, proporcionando a leitura do mesmo. Esta rede, maioritariamente assente em Corredores Verdes, tenciona criar uma nova dinâmica de relações (inter)municipais na região do Baixo-Mondego/Maciço de Sicó aliada a um sistema de transportes multi-modal, introduzindo a bicicleta como alternativa efetiva.This master thesis aims to develop a network of interpretative trails in the County of Condeixa-a-Nova, designed to slow mobilities - preferably the cycling - in an attempt to stimulate the approach of the host community and visitors to the Territory, providing the reading thereof. This network, mainly based on Greenways, intends to create a new dynamic of relations in Baixo Mondego/Maciço de Sicó region combined with a multi-modal transport system, introducing the bicycle as an effective alternative

First Record of the Soil-feeding Higher Termites (Isoptera: Termitidae) from Okinawa Island, the Central Ryukyus, Japan

Some of termites have been introduced outside their native ranges, and it has been suggested that both wood-eating and wood-nesting lifestyles are critical for the transportation of propagules. Here, we present the first record of the soil-feeding and soil-nesting termite Pericapritermes nitobei (Isoptera: Termitidae) in the Motobu Peninsula on the northern part of Okinawa Island in the Central Ryukyus. The fact that the previous extensive surveys of termites in the Ryukyu Archipelago did not detect P. nitobei in the Central Ryukyus, including the Motobu Peninsula, and its discontinuous distribution, indicate that P. nitobei has been recently introduced into the Motobu Peninsula of Okinawa Island from the Yaeyama Islands, similar to the fungus-growing and soil-nesting termite Odontotermes formosanus (Isoptera: Termitidae). Together with O. formosanus in the southern part of Okinawa Island, our findings in this study raise the possibility that non-wood-feeding and non-wood-nesting termites can be introduced and established outside their native ranges by human activities

Enhanced heterozygosity from male meiotic chromosome chains is superseded by hybrid female asexuality in termites

Although males are a ubiquitous feature of animals, they have been lost repeatedly in diverse lineages. The tendency for obligate asexuality to evolve is thought to be reduced in animals whose males play a critical role beyond the contribution of gametes, for example, via care of offspring or provision of nuptial gifts. To our knowledge, the evolution of obligate asexuality in such species is unknown. In some species that undergo frequent inbreeding, males are hypothesized to play a key role in maintaining genetic heterozygosity through the possession of neo-sex chromosomes, although empirical evidence for this is lacking. Because inbreeding is a key feature of the life cycle of termites, we investigated the potential role of males in promoting heterozygosity within populations through karyotyping and genome-wide single-nucleotide polymorphism analyses of the drywood termite Glyptotermes nakajimai. We showed that males possess up to 15 out of 17 of their chromosomes as sex-linked (sex and neo-sex) chromosomes and that they maintain significantly higher levels of heterozygosity than do females. Furthermore, we showed that two obligately asexual lineages of this species—representing the only known all-female termite populations—arose independently via intraspecific hybridization between sexual lineages with differing diploid chromosome numbers. Importantly, these asexual females have markedly higher heterozygosity than their conspecific males and appear to have replaced the sexual lineages in some populations. Our results indicate that asexuality has enabled females to supplant a key role of males

The Antibacterial Protein Lysozyme Identified as the Termite Egg Recognition Pheromone

Social insects rely heavily on pheromone communication to maintain their sociality. Egg protection is one of the most fundamental social behaviours in social insects. The recent discovery of the termite-egg mimicking fungus ‘termite-ball’ and subsequent studies on termite egg protection behaviour have shown that termites can be manipulated by using the termite egg recognition pheromone (TERP), which strongly evokes the egg-carrying and -grooming behaviours of workers. Despite the great scientific and economic importance, TERP has not been identified because of practical difficulties. Herein we identified the antibacterial protein lysozyme as the TERP. We isolated the target protein using ion-exchange and hydrophobic interaction chromatography, and the MALDI-TOF MS analysis showed a molecular size of 14.5 kDa. We found that the TERP provided antibacterial activity against a gram-positive bacterium. Among the currently known antimicrobial proteins, the molecular size of 14.5 kDa limits the target to lysozyme. Termite lysozymes obtained from eggs and salivary glands, and even hen egg lysozyme, showed a strong termite egg recognition activity. Besides eggs themselves, workers also supply lysozyme to eggs through frequent egg-grooming, by which egg surfaces are coated with saliva containing lysozyme. Reverse transcript PCR analysis showed that mRNA of termite lysozyme was expressed in both salivary glands and eggs. Western blot analysis confirmed that lysozyme production begins in immature eggs in queen ovaries. This is the first identification of proteinaceous pheromone in social insects. Researchers have focused almost exclusively on hydrocarbons when searching for recognition pheromones in social insects. The present finding of a proteinaceous pheromone represents a major step forward in, and result in the broadening of, the search for recognition pheromones. This novel function of lysozyme as a termite pheromone illuminates the profound influence of pathogenic microbes on the evolution of social behaviour in termites

Termite queens close the sperm gates of eggs to switch from sexual to asexual reproduction

昆虫が有性生殖と単為生殖を切り替える仕組みを解明 -シロアリ女王、卵の孔を閉じて精子通さず-. 京都大学プレスリリース. 2014-11-18

Comparative screening of endosymbiotic bacteria associated with the asexual and sexual lineages of the termite Glyptotermes nakajimai

Males provide opportunities both for sexual reproduction and for sex-based phenotypic differences within animal societies. In termites, the ubiquitous presence of both male and female workers and soldiers indicate that males play a critical role in colonies of these insects. However, we have recently reported all-female asexual societies in a lineage of the termite Glyptotermes nakajimai – a dramatic transition from mixed-sex to all-female asexual societies. It is known that female-producing parthenogenesis in insects can be induced by maternally inherited endosymbiotic bacteria, such as Wolbachia, Cardinium, and Rickettsia. Here, we screen for the presence of endosymbiotic bacteria in the asexual and sexual lineages of G. nakajimai. Our bacterial screening of the asexual lineage did not reveal any likely causal agents for parthenogenetic reproduction, whereas screening of the sexual lineage resulted in Wolbachia being detected. Our findings suggest that the asexuality in G. nakajimai is likely to be maintained without manipulation by endosymbiotic bacteria

Taxonomic assessment of the termite genus Neotermes (Isoptera: Kalotermitidae) in the Ryukyu-Taiwan Island arc, with description of a new species

Yashiro, Toshihisa, Takematsu, Yoko, Ogawa, Naoki, Matsuura, Kenji (2019): Taxonomic assessment of the termite genus Neotermes (Isoptera: Kalotermitidae) in the Ryukyu-Taiwan Island arc, with description of a new species. Zootaxa 4604 (3): 549-561, DOI: https://doi.org/10.11646/zootaxa.4604.3.1

FIGURE 1 in Taxonomic assessment of the termite genus Neotermes (Isoptera: Kalotermitidae) in the Ryukyu-Taiwan Island arc, with description of a new species

FIGURE 1. Bayesian phylogenetic trees of Neotermes termites in the Ryukyu Archipelago (Neotermes sugioi sp. nov.) and Taiwan (N. koshunensis) based on mitochondrial COII and nuclear ITS2 sequences (left) and mitochondrial COII sequences (right). The corresponding posterior probabilities (± 0.70) are shown by the branches. GenBank accession numbers are shown in parentheses