scholarly journals A lipocalin protein, Neural Lazarillo, is key to social interactions that promote termite soldier differentiation

2018 ◽  
Vol 285 (1883) ◽  
pp. 20180707 ◽  
Author(s):  
Hajime Yaguchi ◽  
Shuji Shigenobu ◽  
Yoshinobu Hayashi ◽  
Satoshi Miyazaki ◽  
Kouhei Toga ◽  
...  
Keyword(s):  
Social Communication ◽  
Social Evolution ◽  
Differentially Expressed Gene ◽  
Social Signals ◽  
Crucial Component ◽  
Insect Societies ◽  
Termite Soldier ◽  
Molecular Phylogenetic ◽  
Incipient Colony ◽  
Soldier Differentiation

Social communication among castes is a crucial component of insect societies. However, the genes involved in soldier determination through the regulation of inter-individual interactions are largely unknown. In an incipient colony of the damp-wood termite Zootermopsis nevadensis , the first larva to develop into a third instar always differentiates into a soldier via frequent trophallactic feeding from the reproductives. Here, by performing RNA-seq analysis of third instar larvae, a homologue of Neural Lazarillo (named ZnNLaz1 ) was found to be the most differentially expressed gene in these soldier-destined larvae, compared with worker-destined larvae. This gene encodes a lipocalin protein related to the transport of small hydrophobic molecules. RNAi-induced knockdown of ZnNLaz1 significantly inhibited trophallactic interactions with the queen and decreased the soldier differentiation rates. This protein is localized in the gut, particularly in the internal wall, of soldier-destined larvae, suggesting that it is involved in the integration of social signals from the queen through frequent trophallactic behaviours. Based on molecular phylogenetic analysis, we suggest that a novel function of termite NLaz1 has contributed to social evolution from the cockroach ancestors of termites. These results indicated that a high larval NLaz1 expression is crucial for soldier determination through social communication in termites.

scholarly journals Dopamine regulates termite soldier differentiation through trophallactic behaviours

2016 ◽  
Vol 3 (2) ◽  
pp. 150574 ◽  
Author(s):  
Hajime Yaguchi ◽  
Takaya Inoue ◽  
Ken Sasaki ◽  
Kiyoto Maekawa
Keyword(s):  
Social Insects ◽  
Caste Differentiation ◽  
Multiple Roles ◽  
Intrinsic Factors ◽  
Termite Soldier ◽  
Species Specific ◽  
Incipient Colony ◽  
Soldier Differentiation ◽  
Gene Expression Levels

Caste polyphenism in social insects is regulated by social interactions among colony members. Trophallaxis is one of the most frequently observed interactions, but no studies have been conducted identifying the intrinsic factors involved in this behaviour and caste differentiation. Dopamine (DA) has multiple roles in the modulation of behaviours and physiology, and it produces species-specific behaviours in animals. Here, to verify the role of DA in termite soldier differentiation, we focused on the first soldier in an incipient colony of Zootermopsis nevadensis , which always differentiates from the oldest 3rd instar (No. 1 larva) via a presoldier. First, brain DA levels of the No. 1 larva at day 3 after its appearance were significantly higher than day 0. Second, DA synthesis gene expression levels were extraordinarily high in the No. 1 larva at day 0–1 after appearance. Finally, injection of a DA receptor antagonist into the No. 1 larva resulted in the inhibition of presoldier differentiation. Behavioural observations of the antagonist or control-injected larvae suggested that brain DA and signalling activity regulate the frequencies of trophallaxis from reproductives and presoldier differentiation. Because trophallaxis is a social behaviour frequently observed in natural conditions, the role of DA should be investigated in other social insects with frequent trophallactic and allogrooming behaviour.

Eusocial Insects as a Model for Understanding Altruism, Cooperation, and Levels of Selection

2020 ◽  
Author(s):  
Heikki Helanterä
Keyword(s):  
Natural Selection ◽  
Division Of Labor ◽  
Social Insect ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Family Structures ◽  
Major Transitions ◽  
Eusocial Insects ◽  
Insect Societies ◽  
Evolutionary Success

If the logic of natural selection is applied strictly at the level of individual production of offspring, sterile workers in insect societies are enigmatic. How can natural selection ever produce individuals that refrain from reproduction, and how are traits of such individuals that never produce offspring scrutinized and changed through natural selection? The solution to both questions is found in the family structures of insect societies. That is, the sterile helper individuals are evolutionary altruists that give up their own reproduction and instead are helping their kin reproduce and proliferate shared genes in the offspring of the fertile queen. Selection in such cases is not just a matter of individual’s direct reproduction, and instead of own offspring, the currency of the evolutionary success of sterile individuals is inclusive fitness. The concept of inclusive fitness and the process of kin selection are key to understanding the magnificent cooperation we see in insect societies, and reciprocally, insect societies are key case studies of inclusive fitness logic. In extreme cases, such as the highly advanced and sophisticated societies of ants, honeybees, and termites, the division of labor and interdependence of colony members is so complete, that it is justified to talk about a new level of evolutionary individuality. Such increases in the hierarchical complexity of life are called major transitions in evolution. We see adaptations of the colony, rather than individuals, in, e.g., their communication and group behaviors. The division of labor between morphologically differentiated queens and workers is analogous to germline-soma separation of a multicellular organism, justifying the term superorganism for the extreme cases of social lifestyle. Alongside these extreme cases, there is enormous diversity in the social lifestyles across social insect taxa, which provides a window into the balance of cooperation and conflict, and individual reproduction and helping others, in social evolution. Over the last decades, social insect research has been an area where the theoretical and empirical understanding have been developed hand in hand, together with examples of wonderful natural history, and has tremendously improved our understanding of evolution.

scholarly journals Adaptation and the genetics of social behaviour

2009 ◽  
Vol 364 (1533) ◽  
pp. 3209-3216 ◽  
Author(s):  
Laurent Keller
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Division Of Labour ◽  
Chemical Signalling ◽  
Insect Societies ◽  
Genetic Mechanisms ◽  
Selective Forces ◽  
Group Members ◽  
Reproductive Division Of Labour ◽  
Reproductive Division

In recent years much progress has been made towards understanding the selective forces involved in the evolution of social behaviour including conflicts over reproduction among group members. Here, I argue that an important additional step necessary for advancing our understanding of the resolution of potential conflicts within insect societies is to consider the genetics of the behaviours involved. First, I discuss how epigenetic modifications of behaviour may affect conflict resolution within groups. Second, I review known natural polymorphisms of social organization to demonstrate that a lack of consideration of the genetic mechanisms involved may lead to erroneous explanations of the adaptive significance of behaviour. Third, I suggest that, on the basis of recent genetic studies of sexual conflict in Drosophila , it is necessary to reconsider the possibility of within-group manipulation by means of chemical substances (i.e. pheromones). Fourth, I address the issue of direct versus indirect genetic effects, which is of particular importance for the study of behaviour in social groups. Fifth, I discuss the issue of how a genetic influence on dominance hierarchies and reproductive division of labour can have secondary effects, for example in the evolution of promiscuity. Finally, because the same sets of genes (e.g. those implicated in chemical signalling and the responses that are triggered) may be used even in species as divergent as ants, cooperative breeding birds and primates, an integration of genetic mechanisms into the field of social evolution may also provide unifying ideas.

Expression Without Recognition: Contributions of the Human Amygdala to Emotional Communication

2000 ◽  
Vol 11 (2) ◽  
pp. 106-111 ◽  
Author(s):  
Adam K. Anderson ◽  
Elizabeth A. Phelps
Keyword(s):  
Social Communication ◽  
Emotional Processing ◽  
Emotional State ◽  
Social Signals ◽  
Basic Emotions ◽  
The Social ◽  
Emotional Appraisal ◽  
Facial Expressions Of Emotion

A growing body of evidence from humans and other animals suggests the amygdala may be a critical neural substrate for emotional processing. In particular, recent studies have shown that damage to the human amygdala impairs the normal appraisal of social signals of emotion, primarily those of fear. However, effective social communication depends on both the ability to receive (emotional appraisal) and the ability to send (emotional expression) signals of emotional state. Although the role of the amygdala in the appraisal of emotion is well established, its importance for the production of emotional expressions is unknown. We report a case study of a patient with bilateral amygdaloid damage who, despite a severe deficit in interpreting facial expressions of emotion including fear, exhibits an intact ability to express this and other basic emotions. This dissociation suggests that a single neural module does not support all aspects of the social communication of emotional state.

scholarly journals Pupil-mimicry conditions trust in partners: moderation by oxytocin and group membership

2017 ◽  
Vol 284 (1850) ◽  
pp. 20162554 ◽  
Author(s):  
Mariska E. Kret ◽  
Carsten K. W. De Dreu
Keyword(s):  
Social Communication ◽  
Group Membership ◽  
Pupil Dilation ◽  
Social Signals ◽  
Social Species ◽  
Trust Games ◽  
Group Life ◽  
Interaction Partners ◽  
Pupil Constriction

Across species, oxytocin, an evolutionarily ancient neuropeptide, facilitates social communication by attuning individuals to conspecifics' social signals, fostering trust and bonding. The eyes have an important signalling function; and humans use their salient and communicative eyes to intentionally and unintentionally send social signals to others, by contracting the muscles around their eyes and pupils. In our earlier research, we observed that interaction partners with dilating pupils are trusted more than partners with constricting pupils. But over and beyond this effect, we found that the pupil sizes of partners synchronize and that when pupils synchronously dilate, trust is further boosted. Critically, this linkage between mimicry and trust was bound to interactions between ingroup members. The current study investigates whether these findings are modulated by oxytocin and sex of participant and partner. Using incentivized trust games with partners from ingroup and outgroup whose pupils dilated, remained static or constricted, this study replicates our earlier findings. It further reveals that (i) male participants withhold trust from partners with constricting pupils and extend trust to partners with dilating pupils, especially when given oxytocin rather than placebo; (ii) female participants trust partners with dilating pupils most, but this effect is blunted under oxytocin; (iii) under oxytocin rather than placebo, pupil dilation mimicry is weaker and pupil constriction mimicry stronger; and (iv) the link between pupil constriction mimicry and distrust observed under placebo disappears under oxytocin. We suggest that pupil-contingent trust is parochial and evolved in social species in and because of group life.

scholarly journals Reproductive Soldier Development Is Controlled by Direct Physical Interactions with Reproductive and Soldier Termites

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 76 ◽  
Author(s):  
Yudai Masuoka ◽  
Keigo Nuibe ◽  
Naoto Hayase ◽  
Takateru Oka ◽  
Kiyoto Maekawa
Keyword(s):  
Social Evolution ◽  
Direct Interaction ◽  
Wire Mesh ◽  
Environmental Cues ◽  
Physical Interaction ◽  
Natural Conditions ◽  
Developmental Mechanism ◽  
Eusocial Insects ◽  
Physical Interactions ◽  
Incipient Colony

In eusocial insects (e.g., ants, bees, and termites), the roles of different castes are assigned to different individuals. These castes possess unique phenotypes that are specialized for specific tasks. The acquisition of sterile individuals with specific roles is considered a requirement for social evolution. In termites, the soldier is a sterile caste. In primitive taxa (family Archotermopsidae and Stolotermitidae), however, secondary reproductives (neotenic reproductives) with their mandibles developed into weapons (so-called reproductive soldiers, also termed as soldier-headed reproductives or soldier neotenics) have been reported. To understand the developmental mechanism of this unique caste, it is necessary to understand the environmental cues and developmental processes of reproductive soldiers under natural conditions. Here, we established efficient conditions to induce reproductive soldiers in Zootermopsis nevadensis. Male reproductive soldiers frequently developed after the removal of both the king and soldiers from an incipient colony. Similarly, high differentiation rates of male reproductive soldiers were observed after king-and-soldier separation treatment using wire mesh. However, no male reproductive soldiers were produced without direct interaction with the queen. These results suggest that male reproductive soldier development is repressed by direct physical interactions with both the king and soldiers and facilitated by direct physical interaction with the queen.

scholarly journals TGFβ signaling related genes are involved in hormonal mediation during termite soldier differentiation

PLoS Genetics ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. e1007338 ◽  
Author(s):  
Yudai Masuoka ◽  
Hajime Yaguchi ◽  
Kouhei Toga ◽  
Shuji Shigenobu ◽  
Kiyoto Maekawa
Keyword(s):  
Tgfβ Signaling ◽  
Termite Soldier ◽  
Soldier Differentiation

scholarly journals Evolutionary transition of doublesex regulation from sex-specific splicing to male-specific transcription in termites

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoshi Miyazaki ◽  
Kokuto Fujiwara ◽  
Keima Kai ◽  
Yudai Masuoka ◽  
Hiroki Gotoh ◽  
...  
Keyword(s):  
Social Evolution ◽  
Target Genes ◽  
Early Stage ◽  
Sex Differentiation ◽  
Sister Group ◽  
Evolutionary Changes ◽  
Molecular Phylogenetic ◽  
Domain Organisation ◽  
Alternatively Spliced ◽  
Male Specific

AbstractThe sex determination gene doublesex (dsx) encodes a transcription factor with two domains, oligomerization domain 1 (OD1) and OD2, and is present throughout insects. Sex-specific Dsx splicing isoforms regulate the transcription of target genes and trigger sex differentiation in all Holometabola examined to date. However, in some hemimetabolous insects, dsx is not spliced sexually and its sequence is less conserved. Here, to elucidate evolutionary changes in dsx in domain organisation and regulation in termites, we searched genome and/or transcriptome databases for the dsx OD1 and OD2 in seven termite species and their sister group (Cryptocercus woodroaches). Molecular phylogenetic and synteny analyses identified OD1 sequences of termites and C. punctulatus that clustered with dsx of Holometabola and regarded them as dsx orthologues. The Cryptocercus dsx orthologue containing OD2 was spliced sexually, as previously shown in other insects. However, OD2 was not found in all termite dsx orthologues. These orthologues were encoded by a single exon in three termites for which genome information is available; they were not alternatively spliced but transcribed in a male-specific manner in two examined species. Evolution of dsx regulation from sex-specific splicing to male-specific transcription may have occurred at an early stage of social evolution in termites.

scholarly journals Finding Hidden Outliers to Promote the Consistency of Key Morphological Traits and Phylogeny in Dennstaedtiaceae

Taxonomy ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 256-265
Author(s):  
Ting Wang ◽  
Li Liu ◽  
Jun-Jie Luo ◽  
Yu-Feng Gu ◽  
Si-Si Chen ◽  
...  
Keyword(s):  
Morphological Traits ◽  
Phylogenetic Analyses ◽  
Morphological Characters ◽  
Open Science ◽  
Systematic Classification ◽  
Spore Ornamentation ◽  
Shared Data ◽  
Phylogenetic Studies ◽  
Crucial Component ◽  
Molecular Phylogenetic

With the development of open science and technological innovation, using sharing data and molecular biology techniques in the study of taxonomy and systematics have become a crucial component of plants, which undoubtedly helps us discover more hidden outliers or deal with difficult taxa. In this paper, we take Dennstaedtia smithii as an example, based on sharing molecular database, virtual herbarium and plant photo bank, to clarify the outliers that have been hidden in Dennstaedtia and find the key morphological traits with consistent of molecular systematics. In molecular phylogenetic analyses, we used rbcL, rps4, psbA-trnH and trnL-F sequences from 5 new and 49 shared data; the results showed that Dennstaedtia smithii is nested within Microlepia rather than Dennstaedtia. We further studied the morphological characters based on the phylogeny result and found that D. smithii is distinguished from other species of Dennstaedtia by spore ornamentation and the unconnected of grooves between rachis and pinna rachis. According to morphological and molecular phylogenetic studies, our results supported that D. smithii should be a new member of Microlepia and renamed Microlepia smithii (Hook.) Y.H. Yan. Finding hidden outliers can promote the consistency of morphological and molecular phylogenetic results, and make the systematic classification more natural.

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