How inquilinism shaped breeding systems in a termite host-inquiline relationship.

Social insects have developed a broad diversity of nesting and foraging strategies. One of these, inquilinism, occurs when one species (the inquiline) inhabits the nest built and occupied by another species (the host). Obligatory inquilines must overcome strong constraints upon colony foundation and development, due to limited availability of host colonies.

Extended longevity of termite kings and queens is accompanied by extranuclear localization of telomerase in somatic organs and caste-specific expression of its isoforms.

Kings and queens of termites are endowed with an extraordinary longevity coupled with lifelong fecundity. We recently reported that termite kings and queens display a dramatically increased enzymatic activity and abundance of telomerase in their somatic organs when compared to short-lived workers and soldiers. We hypothesized that this telomerase activation may represent a noncanonical pro-longevity function, independent of its canonical role in telomere maintenance.

Termite primary queen - ancestral, but highly specialized eusocial phenotype.

Termite eusociality is accompanied by flagrant caste polyphenism manifested by the presence of several sterile (workers and soldiers) and reproductive (imaginal and neotenic kings and queens) caste phenotypes. Imaginal kings and queens are developmentally equivalent to adults of other hemimetabolous insects but display multiple adaptations inherent to their role of eusocial colony founders, such as long lifespan and high fecundity. Herein, we summarize the recent advances in understanding the biology of imaginal (primary) queens as emblematic examples of termite polyphenism acquired during social evolution.

Identification of a queen primer pheromone in higher termites.

It is long established that queens of social insects, including termites, maintain their reproductive dominance with queen primer pheromones (QPPs). Yet, the QPP chemistry has only been elucidated in a single species of lower termites. By contrast, the most diversified termite family Termitidae (higher termites), comprising over 70% of termite species, has so far resisted all attempts at QPP identification.

Binding of de novo synthesized radiolabeled juvenile hormone (JH III) by JH receptors from the Cuban subterranean termite Prorhinotermes simplex and the German cockroach Blattella germanica.

Juvenile hormone (JH) controls insect reproduction and development through an intracellular receptor complex comprising two bHLH-PAS proteins, the JH-binding Methoprene-tolerant (Met) and its partner Taiman (Tai). Many hemimetabolous insects including cockroaches strictly depend on JH for stimulation of vitellogenesis. In termites, the eusocial hemimetabolans, JH also regulates the development of caste polyphenism.

Thermoreflectance Imaging of (Ultra)wide Band-Gap Devices with MoS Enhancement Coatings.

Measuring the maximum operating temperature within the channel of ultrawide band-gap transistors is critically important since the temperature dependence of the device reliability sets operational limits such as maximum operational power. Thermoreflectance imaging (TTI) is an optimal choice to measure the junction temperature due to its submicrometer spatial resolution and submicrosecond temporal resolution. Since TTI is an imaging technique, data acquisition is orders of magnitude faster than point measurement techniques such as Raman thermometry.

Thermal Transport across Metal/β-GaO Interfaces.

In this work, we study the thermal transport at β-GaO/metal interfaces, which play important roles in heat dissipation and as electrical contacts in β-GaO devices. A theoretical Landauer approach was used to model and elucidate the factors that impact the thermal transport at these interfaces. Experimental measurements using time-domain thermoreflectance (TDTR) provided data for the thermal boundary conductance (TBC) between β-GaO and a range of metals used to create both Schottky and ohmic electrical contacts.

Quantifying charge carrier localization in chemically doped semiconducting polymers.

Charge transport in semiconducting polymers ranges from localized (hopping-like) to delocalized (metal-like), yet no quantitative model exists to fully capture this transport spectrum and its dependency on charge carrier density. In this study, using an archetypal polymer-dopant system, we measure the temperature-dependent electrical conductivity, Seebeck coefficient and extent of oxidation. We then use these measurements to develop a semi-localized transport (SLoT) model, which captures both localized and delocalized transport contributions.

Long-lived termite kings and queens activate telomerase in somatic organs.

Kings and queens of termites, like queens of other advanced eusocial insects, are endowed with admirable longevity, which dramatically exceeds the life expectancies of their non-reproducing nest-mates and related solitary insects. In the quest to find the mechanisms underlying the longevity of termite reproductives, we focused on somatic maintenance mediated by telomerase. This ribonucleoprotein is well established for pro-longevity functions in vertebrates, thanks primarily to its ability of telomere extension.

Post-eclosion temperature effects on insect cuticular hydrocarbon profiles.

The insect cuticle is the interface between internal homeostasis and the often harsh external environment. Cuticular hydrocarbons (CHCs) are key constituents of this hard cuticle and are associated with a variety of functions including stress response and communication. CHC production and deposition on the insect cuticle vary among natural populations and are affected by developmental temperature; however, little is known about CHC plasticity in response to the environment experienced following eclosion, during which time the insect cuticle undergoes several crucial changes.

Improvement of Flow Velocity Measurement Algorithms Based on Correlation Function and Twin Plane Electrical Capacitance Tomography.

This article discusses the correlation method for time delay estimation, its disadvantages, and drawbacks. It is shown that the correlation method for material velocity measurement based on images of instantaneous changes of the concentration material inside measured by twin planes electrical tomography has serious limitations, especially in the case of plug regime. The basic problem is the non-stationarity of measured data, therefore the requirement of of input data should be fulfilled.

Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency.

The influence of micro/nanostructure on thermal conductivity is a topic of great scientific interest, particularly to thermoelectrics. The current understanding is that structural defects decrease thermal conductivity through phonon scattering where the phonon dispersion and speed of sound are assumed to remain constant. Experimental work on a PbTe model system is presented, which shows that the speed of sound linearly decreases with increased internal strain.

(3R,6E)-nerolidol, a fertility-related volatile secreted by the queens of higher termites (Termitidae: Syntermitinae).

The queens of advanced social insects maintain their reproductive monopoly by using exocrine chemicals. The chemistry of these "queen pheromones" in termites is poorly known. We show that primary queens of four higher termites from the subfamily Syntermitinae (Embiratermes neotenicus, Silvestritermes heyeri, Labiotermes labralis, and Cyrilliotermes angulariceps) emit significant amounts of the sesquiterpene alcohol (E)-nerolidol.

Exquisite ligand stereoselectivity of a juvenile hormone receptor contrasts with its broad agonist repertoire.

The sesquiterpenoid juvenile hormone (JH) is vital to insect development and reproduction. Intracellular JH receptors have recently been established as basic helix-loop-helix transcription factor (bHLH)/PAS proteins in known as germ cell-expressed (Gce) and its duplicate paralog, methoprene-tolerant (Met). Upon binding JH, Gce/Met activates its target genes.

Identification and Enantiodivergent Synthesis of (5 Z,9 S)-Tetradec-5-en-9-olide, a Queen-Specific Volatile of the Termite Silvestritermes minutus.

The queens of social insects differ from sterile colony members in many aspects of their physiology. Besides adaptations linked with their specialization for reproduction and extended lifespan, the queens also invest in the maintenance of their reproductive dominance by producing exocrine chemicals signaling their presence to the nestmates. The knowledge of the chemistry of queen-specific cues in termites is scarce.

Melt-Centrifuged (Bi,Sb) Te : Engineering Microstructure toward High Thermoelectric Efficiency.

Microstructure engineering is an effective strategy to reduce lattice thermal conductivity (κ ) and enhance the thermoelectric figure of merit (zT). Through a new process based on melt-centrifugation to squeeze out excess eutectic liquid, microstructure modulation is realized to manipulate the formation of dislocations and clean grain boundaries, resulting in a porous network with a platelet structure. In this way, phonon transport is strongly disrupted by a combination of porosity, pore surfaces/junctions, grain boundaries, and lattice dislocations.

Metabolomic and transcriptomic data on major metabolic/biosynthetic pathways in workers and soldiers of the termite (Isoptera: Rhinotermitidae) and chemical synthesis of intermediates of defensive ()-nitropentadec-1-ene biosynthesis.

Production of nitro compounds has only seldom been recorded in arthropods. The aliphatic nitroalkene ()-nitropentadec-1-ene (), identified in soldiers of the termite genus , was the first case documented in insects in early seventies. Yet, the biosynthetic origin of has long remained unknown.

Sex-Pairing Pheromones in Three Sympatric Neotropical Termite Species (Termitidae: Syntermitinae).

Termite colonies are almost always founded by a pair of winged dispersers, in spite of the high costs and low success rates inherent in independent colony foundation. The dispersal flights of imagoes from natal colonies are followed by mate search, mediated by sex-pairing pheromones. Here, we studied the chemistry of sex-pairing pheromones and the related aspects of mate search in winged imagoes of two facultatively parthenogenetic species, Embiratermes neotenicus and Silvestritermes minutus, and an additional species from the same subfamily, Silvestritermes heyeri.

Secondary queens in the parthenogenetic termite Cavitermes tuberosus develop through a transitional helper stage.

In termite species with asexual queen succession (AQS), parthenogenetically produced immatures mostly differentiate into secondary queens, called "neotenics." In order to elucidate the ontogenetic origin of neotenics in Cavitermes tuberosus (Termitidae: Termitinae), a neotropical termite with AQS, we investigated developmental pathways of offspring according to their sex and genetic origin using both morphometric and genetic tools. The caste system of C.