In Drosophila melanogaster, the sex pheromone produced by males, cis-vaccenyl acetate (cVA), evokes a stereotypic gender-specific behavior in both males and females. As Drosophila adults feed, mate, and oviposit on food, they perceive the pheromone as a blend against a background of food odors. Previous studies have reported that food odors enhance flies’ behavioral response to cVA, specifically in virgin females. However, how and where the different olfactory inputs interact has so far remained unknown. In this study, we elucidated the neuronal mechanism underlying the response at an anatomical, functional, and behavioral level. Our data show that in virgin females cVA and the complex food odor vinegar evoke a synergistic response in the cVA-responsive glomerulus DA1. This synergism, however, does not appear at the input level of the glomerulus, but is restricted to the projection neuron level only. Notably, it is abolished by a mutation in gap junctions in projection neurons and is found to be mediated by electrical synapses between excitatory local interneurons and projection neurons. As a behavioral consequence, we demonstrate that virgin females in the presence of vinegar become receptive more rapidly to courting males, while male courtship is not affected. Altogether, our results suggest that lateral excitation via gap junctions modulates odor tuning in the antennal lobe and drives synergistic interactions between two ecologically relevant odors, representing food and sex.

Pathogens and parasites can manipulate their hosts to optimize their own fitness. For instance, bacterial pathogens have been shown to affect their host plants’ volatile and non-volatile metabolites, which results in increased attraction of insect vectors to the plant, and, hence, to increased pathogen dispersal. Behavioral manipulation by parasites has also been shown for mice, snails and zebrafish as well as for insects. Here we show that infection by pathogenic bacteria alters the social communication system of Drosophila melanogaster. More specifically, infected flies and their frass emit dramatically increased amounts of fly odors, including the aggregation pheromones methyl laurate, methyl myristate, and methyl palmitate, attracting healthy flies, which in turn become infected and further enhance pathogen dispersal. Thus, olfactory cues for attraction and aggregation are vulnerable to pathogenic manipulation, and we show that the alteration of social pheromones can be beneficial to the microbe while detrimental to the insect host.

Plants produce chemical defense compounds to resist herbivore attack either by repelling the herbivores or attracting natural enemies of the herbivores. We have previously shown that volatile compounds from cotton released in response to herbivory by conspecifics reduce oviposition in cotton leafworm moth Spodoptera littoralis. It remained, however, unclear whether herbivore-induced changes also affect moth pre-mating and mating behaviors. In this study we examined the effect of herbivore-induced changes in cotton on reproductive behaviors i.e., female calling, male attraction and investment, and mating behavior in S. littoralis. We found a reduction in the number of females calling i.e., females releasing pheromone, in the presence of cotton plants damaged by larvae of S. littoralis compared to undamaged plants. Females also spent significantly less time calling and showed a delay in calling in the presence of damaged plants. Furthermore, males exhibited significantly delayed activation and reduced attraction toward female sex pheromone in the presence of damaged plants. We also found that mating success and the number of matings were significantly reduced in the presence of damaged plants whereas male investment i.e., spermatophore weight, was not affected. Thus, our study provides evidence that herbivory by conspecifics on host plants affect pre-mating and mating behaviors in an insect herbivore.

The vinegar fly Drosophila melanogaster is equipped with two peripheral olfactory organs, antenna and maxillary palp. The antenna is involved in finding food, oviposition sites and mates. However, the functional significance of the maxillary palp remained unknown. Here, we screened the olfactory sensory neurons of the maxillary palp (MP-OSNs) using a large number of natural odor extracts to identify novel ligands for each MP-OSN type. We found that each type is the sole or the primary detector for a specific compound, and detects these compounds with high sensitivity. We next dissected the contribution of MP-OSNs to behaviors evoked by their key ligands and found that MP-OSNs mediate short- and long-range attraction. Furthermore, the organization, detection and olfactory receptor (Or) genes of MP-OSNs are conserved in the agricultural pest D. suzukii. The novel short and long-range attractants could potentially be used in integrated pest management (IPM) programs of this pest species.

Divergent populations across different environments are exposed to critical sensory information related to locating a host or mate, as well as avoiding predators and pathogens. These sensory signals generate evolutionary changes in neuroanatomy and behavior; however, few studies have investigated patterns of neural architecture that occur between sensory systems, or that occur within large groups of closely-related organisms. Here we examine 62 species within the genus Drosophila and describe an inverse resource allocation between vision and olfaction, which we consistently observe at the periphery, within the brain, as well as during larval development. This sensory variation was noted across the entire genus and appears to represent repeated, independent evolutionary events, where one sensory modality is consistently selected for at the expense of the other. Moreover, we provide evidence of a developmental genetic constraint through the sharing of a single larval structure, the eye-antennal imaginal disc. In addition, we examine the ecological implications of visual or olfactory bias, including the potential impact on host-navigation and courtship.

common fixed points of general-type contraction mappings mappings for approximating common flxed points of three mappings satisfying general contraction type conditions is introduced and its strong convergence is proved in uniformly convex Banach

common fixed points of general-type contraction mappings mappings for approximating common flxed points of three mappings satisfying general contraction type conditions is introduced and its strong convergence is proved in uniformly convex Banach

Straight nanowires fabricated from single-layer porous anodic alumina (PAA) templates are known to be mechanically weak. To provide additional support, nanowires can be fabricated on multilayered PAA templates. In this work, Cu and Ni nanowires were fabricated from single-, double-, and three-layer PAA templates using pulse electrochemical deposition (PECD). The templates were made by anodizing Al-1 wt% Si and Al-0.5 wt% Cu thin films under different conditions. The morphologies of the PAA templates and fabricated nanowires were examined with scanning electron microscopy. The length of the nanowires was 3 µm, while the diameters ranged from 50 to 70 nm. The nanowires fabricated from a double-layered template (Al-0.5 wt% Cu/Al-1 wt% Si) were mechanically stronger with larger surface areas than those fabricated from an anodized Al-1 wt% Si template. The nanowires formed within the …

Thin films (~ 150 nm) of amorphous As30Te70−xGax (where x = 0, 1, 3, 6, and 10 at%) are prepared through thermal evaporation of As30Te70−xGax bulk samples on glass substrates. X-ray powder diffraction (XRD) analysis reveals the amorphous nature of the as-prepared As30Te70−xGax thin films. The influence of Ga content on the As30Te70−xGax thin films’ linear and nonlinear optical properties is determined based on the optical reflectance and transmittance spectra. The estimated (direct or indirect) optical bandgap decreases with an increase in Ga content up to 3 at% and then increases, whereas the Urbach energy exhibits an opposite trend. The linear and nonlinear refractive indices, extension coefficient, optical conductivity, electrical conductivity and nonlinear susceptibility, optical density, inter-band transition strength, etc., are found to be significantly influenced by Ga content and the energy of incident waves. The As30Te67Ga3 composition can be considered as a puzzling compound as most of the investigated parameters in As30Te70−xGax alloys demonstrate opposite behaviors around that composition. Moreover, the optical surface resistance and thermal emission of As30Te70−xGax thin films are estimated from the investigated optical parameters and it was found that they are dependent on Ga content. The obtained results enhanced basic understanding and showed that the As–Te–Ga system qualifies for various optoelectronic applications.

In the present study, hybrid organic–inorganic composites were fabricated from epoxy–TEOS (tetraethyl orthosilicate, Si(OC2H5)4) with various ratios (0–10 wt%) of multiwall carbon nanotubes (MWCNTs) as reinforcing nanofillers by the sol–gel method. The effect of the MWCNTs ratios on the structural, optical and mechanical characteristics and the thermal conductivity of the epoxy–TEOS/MWCNTs composites is investigated. The X-ray diffraction (XRD) analysis reveals that the pure epoxy-TEOS is amorphous, while epoxy–TEOS/MWCNTs composites are crystalline with an orthorhombic crystal structure that has an average crystallite size of 3.9 ± 0.15 nm. In addition, thermal stability and thermal conductivity were improved by adding TEOS and MWCNTs, whereas the exothermic peak temperature decreases compared with pure epoxy-TEOS. Similarly, the hardness Shore-D and tensile strength reach the optimum value at 4 wt% MWCNTs content. The significant improvement in the mechanical and thermal properties of the prepared composites could be attributed to the synergistic effect of MWCNTs and epoxy–TEOS which was emphasized by Fourier transform infrared (FTIR) spectroscopy. Moreover, epoxy-TEOS sample has high optical transmittance (T) within the visible region, but the composites samples are transparent at λ  800 nm and have a lower value of T. The indirect optical band gap decreases from 3.59 to 2.91 eV with an increase in MWCNTs fractions from 0 to 10 wt%, respectively. However, the glass transition reflects the onset of decomposition temperatures was also considerably increased. The acquired outcomes such as a large increase in thermal conductivity and tensile stress coupled with reduced T make the composites readily applicable for a variety of applications.