Specific Pheromone Research Articles

Unlocking the Secrets of Pheromones: Reproductive and Social Communication in Domestic Mammals

Pheromones play a pivotal role in the reproductive and behavioural management of livestock, influencing various physiological and behavioural responses within and across species. This review explores the application of pheromones in cattle, buffalo, sheep, goats, pigs, and equines, highlighting their significant impact on reproductive efficiency, stress reduction, and animal welfare. In cattle, pheromones are essential for estrus detection and the enhancement of maternal bonding. Similarly, in buffaloes, urinary pheromones have been identified as markers for estrus detection, aiding in overcoming the challenge of silent ovulation, while also contributing to penis erection and sperm quantity enhancement. In small ruminants such as sheep and goats, the "male effect" accelerates puberty and synchronizes estrus, which is crucial for optimizing breeding cycles. In pigs, the presence of boars accelerates puberty in gilts and reduces postpartum anestrus in sows, enhancing reproductive outcomes. Equines benefit from appeasing pheromones, which alleviate stress in foals and adult horses, particularly during transportation and other stressful events. The synthesis and application of synthetic analogs of these pheromones have demonstrated practical benefits in animal husbandry, offering promising avenues for improving reproductive performance and animal welfare. However, despite these advancements, the identification and characterization of specific pheromones across different species remain incomplete. Future research should focus on the molecular identification of these pheromones, their mechanisms of action, and the development of innovative applications to further enhance their utility in animal management.

Microbial Biotransformation of Male Specific Pheromone α-Copaene with Cunninghamella elegans and Antibacterial Activity of Its Transformed Products

Pharmaceutical industries are increasingly turning to microbial transformation instead of chemical methods. This is because microbial biotransformation is a more effective way to produce pharmacologically active molecules with high specificity and efficient yield. Additionally, it is a step towards eco-friendly synthesis. α-Copaene (1), a tricyclic sesquiterpene, is a potent attractant of the male Mediterranean fruit fly Ceratitis capitata. This paper presents the utilization of the filamentous fungus Cunninghamella elegans TSY 0865 for large-scale biotransformation of 1. α-Copaene (1) has been incubated with Cunninghamella elegans for 11 days and extracted with CH2Cl2. Four new hydroxylated metabolites 10,13-dihydroxycopaene (2); 11,13-dihydroxycopaene (3); 11-hydroxycopaen-5-one (4); and 11-hydroxy-13-copaenic acid (5) were afforded. The structures of the new metabolites were elucidated by 1D (1H, 13C) and 2D NMR (COSY, HMBC, HMQC, and NOESY) techniques and MS analyses. Metabolite 5 exhibited significant antibacterial activity against Bacillus subtilis and Pseudomonas aeruginosa.

Taste and pheromonal inputs govern the regulation of time investment for mating by sexual experience in male Drosophila melanogaster.

Males have finite resources to spend on reproduction. Thus, males rely on a 'time investment strategy' to maximize their reproductive success. For example, male Drosophila melanogaster extends their mating duration when surrounded by conditions enriched with rivals. Here we report a different form of behavioral plasticity whereby male fruit flies exhibit a shortened duration of mating when they are sexually experienced; we refer to this plasticity as 'shorter-mating-duration (SMD)'. SMD is a plastic behavior and requires sexually dimorphic taste neurons. We identified several neurons in the male foreleg and midleg that express specific sugar and pheromone receptors. Using a cost-benefit model and behavioral experiments, we further show that SMD behavior exhibits adaptive behavioral plasticity in male flies. Thus, our study delineates the molecular and cellular basis of the sensory inputs required for SMD; this represents a plastic interval timing behavior that could serve as a model system to study how multisensory inputs converge to modify interval timing behavior for improved adaptation.

Colonization of oak stumps by the oak pinhole borer in temperate forests and the efficacy of pheromone traps: Implications for pest management

IntroductionThe present changes in climate and land use have led to an increase in pest population densities. The oak pinhole borer, Platypus cylindrus, is one of the ambrosia beetles, which are known to infect wood tissue with fungi from their mycangia. These fungi are responsible for cellulose degradation. This species is now responsible for more frequent timber damage throughout Europe. Therefore, it is assumed that there is a high risk of P. cylindrus outbreaks in the future with possible subsequent oak diebacks. We focused on (1) the influence of stump diameter on P. cylindrus attraction and abundance; (2) the trapping efficacy by a specific pheromone and the impact on nontarget arthropods; and (3) interannual changes in trap catches.MethodsThe research was performed from 2015–2017 with a postharvest survey of stumps. We further analyzed the catches of P. cylindrus and of nontarget arthropods on pheromone traps compared to ethanol-baited traps.Results and discussionIn total, 12,504 adults were trapped during the 3 years of the study. P. cylindrus abundance was positively correlated with stump diameter and interannual changes. The type of compound used for trapping positively affected the trapping efficacy. However, the pheromone type did not have an impact on nontarget beetles. We consider oak stumps to be a reservoir the oak pinhole borer. Therefore, we recommend their debarking or removal, especially in the case of stumps with a larger diameter (over 61 cm).

Kinetics of Odorant Recognition with a Graphene-Based Olfactory Receptor Mimicry

Malaria vector mosquito species rely on a handful of specific pheromones for mating; one of them, sulcatone (6-methyl-5-hepten-2-one), is also found in human exudation. Therefore, a complete understanding of the insect’s olfaction, and rapid real-time methods for odorant detection, are required. Here, we mimic the odorant recognition of the nerve cells of an insect’s antenna with a synthetic graphene-based bio-electro-interfacial odorant receptor. By this means, we obtain the kinetics of the genuine odorant recognition reaction and compare them to electro-antennogram data that represent the more complex scenario of a living insect. The odorant-binding proteins OBP 9A and 9B only associate with their ligands weakly, showing KDs of between 2.1 mM and 3 mM, while the binding kinetics of OBP proteins depend on the structural feature of a cystine knot and are modulated by the local milieu within a protein-aided enhancement zone.

Seasonal, Landscape, and Attractant Effects on Lesser Grain Borer, Rhyzopertha dominica (F.), Captures in Northeast Kansas

The lesser grain borer, Rhyzopertha dominica (F.), is a highly diverse feeder and widely distributed throughout the United States in agricultural and non-agricultural landscapes. Six four-funnel Lindgren traps were deployed in feed mill, grain elevator, and native prairie landscapes, to determine the most attractive food and pheromone combination (attractant) and patterns in seasonal captures. Traps were baited with combinations of wheat (crimped, high moisture, pre-fed) with or without an R. dominica specific aggregation pheromone in 2017 and 2018. Traps were deployed for 48 h, collected, and the number of R. dominica counted. Rhyzopertha dominica was captured among all landscapes with all attractants. There was a significant correlation between temperature and R. dominica captures, with peak captures occurring during the warmest months. Significantly more R. dominica adults were captured in traps containing the pheromone. In 2017, pheromone traps captured 818% more R. dominica and 543% more than in 2018. The pheromone component in the trap was more attractive than any natural stored wheat condition and should be included in future studies. Understanding the seasonal patterns and changes in capture rates in agricultural and non-agricultural landscapes may be useful in determining times of increased immigration pressure into the newly harvested grain.

USE OF EXPERT SOFTWARE AND PHEROMONES TRAPS FOR BIOCENOTIC STRESS MONITORING AND EARLY WARNING OF TREATMENTS AGAINST INSECTS IN ORCHARDS

This paper presents our results in use of the specialized software and specific modules for microclimate monitoring and pest biological cycle assessment, to evaluate and quantify the attack risk for microclimate monitoring, combined with 6 type specific pheromones produced in Romania, in order to determine their efficacy in detecting the targeted micro Lepidoptera, assess their population flight pattern, as well and the biocenotic stress, both tools categories aiming to the precise positioning of the treatments to achieve integrated pests management and reduce the overall impact of the treatments with insecticides on the environment. According the fruit species, several strategies have been defined and followed by several insecticide applications into the bearing orchards, to achieve a better control of damaging micro Lepidoptera. Use of the mixed monitoring systems in tandem with specific pheromones contributed to a more efficient use of the insecticides and increased performances, both for pome and stone fruit species as well.

Cryptococcus neoformans VNII as the Main Cause of Cryptococcosis in Domestic Cats from Rio de Janeiro, Brazil.

Cryptococcosis is a systemic fungal disease acquired from contaminated environments with propagules of the basidiomycetous yeasts of the Cryptococcus neoformans and C. gattii species complexes. The C. neoformans species complex classically comprises four major molecular types (VNI, VNII, VNIII, and VNIV), and the C. gattii species complex comprises another four (VGI, VGII, VGIII, and VGIV) and the newly identified molecular type VGV. These major molecular types differ in their epidemiological and ecological features, clinical presentations, and therapeutic outcomes. Generally, the most common isolated types are VNI, VGI, and VGII. The epidemiological profile of cryptococcosis in domestic cats is poorly studied and cats can be the sentinels for human infections. Therefore, the present study aimed to determine the molecular characterization of Cryptococcus spp. isolated from domestic cats and their dwellings in the metropolitan area of Rio de Janeiro, Brazil. A total of 36 Cryptococcus spp. strains, both clinical and environmental, from 19 cats were subtyped using multilocus sequence typing (MLST). The ploidy was identified using flow cytometry and the mating type was determined through amplification with specific pheromone primers. All strains were mating type alpha and 6/36 were diploid (all VNII). Most isolates (63.88%) were identified as VNII, a rare molecular type, leading to the consideration that this genotype is more likely related to skin lesions, since there was a high percentage (68.75%) of cats with skin lesions, which is also considered rare. Further studies regarding the molecular epidemiology of cryptococcosis in felines are still needed to clarify the reason for the large proportion of the rare molecular type VNII causing infections in cats.

A trail pheromone mediates the mutualism between ants and aphids

Mutualisms, such as the ones between ants and aphids, evolve and persist when benefits outweigh the costs from the interactions between the partners. We show here that the trail pheromone of the red imported fire ant, Solenopsis invicta, can enhance these benefits by suppressing aphid dispersal and stimulating their reproduction. The ant's mutualistic partner, the cotton aphid Aphis gossypii, was found to readily perceive and respond to two specific trail pheromone components. Two pheromone components, Z,E-α-farnesene and E,E-α-farnesene, both suppressed walking dispersal of apterous aphids, whereas only the major pheromone component, Z,E-α-farnesene, also increased aphid reproduction rate. The ants, as well as the aphids, benefit from this inter-species function of the trail pheromone. For the ants it increases and prolongs the availability of honeydew as a key food source, whereas the aphid colony benefits from faster population growth and continuous ant-provided protection. These findings reveal a hitherto unknown mechanism by which ants and aphids both increase the benefits that they provide to each other, thereby likely enhancing the stability of their mutualistic relationship.

An ionic lock and a hydrophobic zipper mediate the coupling between an insect pheromone receptor BmOR3 and downstream effectors

Pheromone receptors (PRs) recognize specific pheromone compounds to guide the behavioral outputs of insects, which are the most diverse group of animals on earth. The activation of PRs is known to couple to the calcium permeability of their coreceptor (Orco) or putatively with G proteins; however, the underlying mechanisms of this process are not yet fully understood. Moreover, whether this transverse seven transmembrane domain (7TM)-containing receptor is able to couple to arrestin, a common effector for many conventional 7TM receptors, is unknown. Herein, using the PR BmOR3 from the silk moth Bombyx mori and its coreceptor BmOrco as a template, we revealed that an agonist-induced conformational change of BmOR3 was transmitted to BmOrco through transmembrane segment 7 from both receptors, resulting in the activation of BmOrco. Key interactions, including an ionic lock and a hydrophobic zipper, are essential in mediating the functional coupling between BmOR3 and BmOrco. BmOR3 also selectively coupled with Gi proteins, which was dispensable for BmOrco coupling. Moreover, we demonstrated that trans-7TM BmOR3 recruited arrestin in an agonist-dependent manner, which indicates an important role for BmOR3–BmOrco complex formation in ionotropic functions. Collectively, our study identified the coupling of G protein and arrestin to a prototype trans-7TM PR, BmOR3, and provided important mechanistic insights into the coupling of active PRs to their downstream effectors, including coreceptors, G proteins, and arrestin.

Anatomical Comparison of Antennal Lobes in Two Sibling Ectropis Moths: Emphasis on the Macroglomerular Complex.

Ectropis obliqua and Ectropis grisescens are two sibling moth species of tea plantations in China. The male antennae of both species can detect shared and specific sex pheromone components. Thus, the primary olfactory center, i.e., the antennal lobe (AL), plays a vital role in distinguishing the sex pheromones. To provide evidence for the possible mechanism allowing this distinction, in this study, we compared the macroglomerular complex (MGC) of the AL between the males of the two species by immunostaining using presynaptic antibody and propidium iodide (PI) with antennal backfills, and confocal imaging and digital 3D-reconstruction. The results showed that MGC of both E. obliqua and E. grisescens contained five glomeruli at invariant positions between the species. However, the volumes of the anterior-lateral glomerulus (ALG) and posterior-ventral (PV) glomerulus differed between the species, possibly related to differences in sensing sex pheromone compounds and their ratios between E. obliqua and E. grisescens. Our results provide an important basis for the mechanism of mating isolation between these sibling moth species.

Study on Specific Apis cerana Honeybee Queen Pheromone Biosensor Based on Pheromone-Binding Protein ASP1

Biosensor is a detection device composed of a biologically active unit and a signal converter. In a eusocial honeybee colony, worker bees have also evolved a sophisticated olfactory system to specifically sense the queen pheromone components. So far, it is not clear whether it is possible to design a biosensor to detect the queen pheromone in vitro by using worker bees' olfactory system. In this study, a specific pheromone biosensor was successfully constructed by immobilizing the recombinant honeybees' pheromone binding protein 1 (PBP1/ASP1) on the forked finger gold electrode using nitrocellulose membrane. The results showed that the maximum resistance charge transfer (Rct) changes of two queen pheromone components [methyl p-hydroxy-benzoate (HOB) and vanillyl alcohol (HVA)] reached 60%, which were significantly higher than those of a bee larval pheromone component (ethyl oleate), and a floral volatile ($\beta $ -ionone). The linear detection of HOB and HVA ranged from 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> mol/L, and the theoretical detection limit reached 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> mol/L, indicating the wide detection linear range and excellent detection capability of this biosensor. These results indicated that the biosensor was highly sensitive and specific to the queen pheromone components. It is beneficial to protect and maintain the sustainability of honeybee resources in the future.

Environmental friendly technique to control cotton pink bollworm Pectinophora gossypiella in Egypt

The cotton bollworms are major pests that reduce yield and quality of the growing cotton crop all over the world. (PBW) pink bollworm Pectinophora gossypiella onseder acommon injurious bollworms of cotton in Egypt, a field studies were performed to evaluate the management of mercantile bollworm pheromones and/with parasitoid Trichogramma evenecens, compared with recommended bollworms insecticides, carried out at El-Behira, governorate, Egypt, during two cotton seasons (2018 and 2019) to reduce the population’s density of (PBW) pink bollworm Pectinophora gossypiella. The obtained results revealed that the treatment of pheromones and/ with parasitoids induced real reduction of pink bollworm infestation (90%) followed by insecticide (88–87%) in both seasons respectively. Furthermore, the costly economic ratio of pheromones and/with parasitoids was less than insecticides and gave highest cotton yield. Specific friendly technique pheromones and/with parasitoids had good potential for providing effective protection system for Pink bollworm.

An Initial Open-Label Study of a Novel Pheromone Complex for Use in Cats

Background: A number of specific synthetic pheromones have been commercially available for many years and used to help modify different problem behaviours exhibited by companion animals. Recently, a new synthetic feline pheromone complex has been patented and made available commercially. Objectives: This study was designed as an initial open-label uncontrolled trial to evaluate the potential impact of the new synthetic pheromone complex on a range of different problem behaviours in pet cats. Methods: 150 owned pet cats from either one-cat (n = 66) or two-cat (n = 84) households that had one or more of four defined problem behaviours (urine spraying, n = 31; scratching furnishings, n = 113; fear, n = 63; or inter-cat conflict, n = 25), were recruited to a 28-day study of a new plug-in diffuser containing the novel feline pheromone complex. Results: By day 28, significant (P values ≤ 0.01) improvements were seen in both the frequency and intensity of all four problem behaviours, as assessed by the owners using blinded questionnaires. A reduction in the frequency of individual problem behaviours was reported by 69.8% - 77.4% of owners and a reduction in the intensity of the problem by 64.0% - 74.2%. Conclusions: The results of this study support the concept that the new feline pheromone complex may have the ability to address multiple problem behaviours. Nevertheless, further controlled studies will be necessary and important to both confirm, and to fully assess the clinical efficacy of the product.

Structural evidence for pheromone discrimination by the pheromone binding protein 3 from Plutella xylostella

Insect pheromone binding proteins (PBPs) are believed to have a high degree of pheromone selectivity, acting as the first filter to discriminate specific pheromones from other volatile compounds. Herein, we provide evidence using homology-based model for the pheromone discrimination of Plutella xylostella pheromone binding protein 3 (PxPBP3). Combining molecular dynamics simulations and in vitro binding assays, two dominant sites are determined to be essential for the PxPBP3 to discriminate (Z)-11-hexadecenyl acetate (Hexadecenyl) from (Z)-11-hexadecenal (Hexadecenal). As the first key site for pheromone discrimination, Arg111 is indispensable to the PxPBP3-Hexadecenyl interaction. However, its importance in the binding of Hexadecenal to PxPBP3 is greatly reduced. A second site where pheromone discrimination occurs is a small loop (residues 34–38) in PxPBP3. It is shown that the hydrophobic strength provided by three hydrophobic residues (Phe34, Tyr37, and Trp38) in the small loop is significantly biased in the two complexes formed by PxPBP3 and the two pheromones. The discrimination capacity of PxPBP3 indicates that the P. xylostella pheromones may not share the same peri-receptor pathway, although they both show high affinity to PxPBP3.

Disparity of Phoresy in Mesostigmatid Mites upon Their Specific Carrier Ips typographus (Coleoptera: Scolytinae).

Simple SummaryThis study investigated the phoretic relationship between mites and one of the most aggressive spruce bark beetles from Eurasia. During one season (April–September), bark beetles Ips typographus were collected with a specific synthetic aggregation pheromone. In the lab, we investigated the diversity of mites associated with I. typographus, mite preferences concerning the body parts of the beetles and how phoretic relationships change during the bark beetle’s flight season. Six phoretic mites species were found and 20% of beetles carried mites. Phoretic mite loads and the percent of beetles with mites were highest during the spring flight period. Phoretic mite species had specific preferences regarding their location on the body of the carrier.Ips typographus Linnaeus, 1758, the most important pest of Norway spruce (Picea abies Linnaeus, 1753) from Eurasia has damaged, in the last decades, a large area of forest in Romania. Associations between beetles and their symbiotic fungi are well known compared to beetle-mite relationships. The objectives of the study are to determine: (i) the diversity of mites species associated with I. typographus in a local outbreak from Central Romania; (ii) the mite’s preferences concerning the body parts of their carriers; and (iii) how phoresy changes during seasonal flight activity of the host. A total of 7896 adult I. typographus were analyzed and six mite species (both adults and immature stages) were found: Dendrolaelaps quadrisetus Berlese,1920, Proctolaelaps fiseri Samsinak, 1960, Trichouropoda polytricha Vitzthum, 1923, Histiostoma piceae Scheucher, 1957, Uroobovella ipidis Vitzthum, 1923, and Uroobovella vinicolora Vitzthum, 1926. Most mites were observed under the carriers’ elytra (46.8%), while 26.7% and 25.8% were seen on the thorax and elytral declivities, respectively. Mite phoresy peaked in the spring corresponding to the dispersal flight of the carrier. A smaller peak in phoresy occurred in the summer during the second beetle generation.

Two highly related odorant receptors specifically detect α-bile acid pheromones in sea lamprey (Petromyzon marinus)

Pheromones play critical roles in habitat identification and reproductive behavior synchronization in the sea lamprey (Petromyzon marinus). The bile acid 3-keto petromyzonol sulfate (3kPZS) is a major component of the sex pheromone mixture from male sea lamprey that induces specific olfactory and behavioral responses in conspecific individuals. Olfactory receptors interact directly with pheromones, which is the first step in their detection, but identifying the cognate receptors of specific pheromones is often challenging. Here, we deorphanized two highly related odorant receptors (ORs), OR320a and OR320b, of P. marinus that respond to 3kPZS. In a heterologous expression system coupled to a cAMP-responsive CRE-luciferase, OR320a and OR320b specifically responded to C24 5α-bile acids, and both receptors were activated by the same set of 3kPZS analogs. OR320a displayed larger responses to all 3kPZS analogs than did OR320b. This difference appeared to be largely determined by a single amino acid residue, Cys-792.56, the C-terminal sixth residue relative to the most conserved residue in the second transmembrane domain (2.56) of OR320a. This region of TM2 residues 2.56-2.60 apparently is critical for the detection of steroid compounds by odorant receptors in lamprey, zebrafish, and humans. Finally, we identified OR320 orthologs in Japanese lamprey (Lethenteron camtschaticum), suggesting that the OR320 family may be widely present in lamprey species and that OR320 may be under purifying selection. Our results provide a system to examine the origin of olfactory steroid detection in vertebrates and to define a highly conserved molecular mechanism for steroid-ligand detection by G protein-coupled receptors.

The Effect of Pheromone Synthesis and Gland Retraction on Translocation and Dynamics of Pheromone Release in the Moth Chloridea virescens.

Most species of moths use a female-produced sex pheromone to bring mates together. Typically, sex pheromone is synthesized in a specialized gland and released during the behavior of "calling", in which the ovipositor and gland are extruded, allowing pheromone to evaporate. Although there has been much study on how a gland makes specific pheromone components, we know relatively little about how it actually functions with regard to synthesis, storage and release. In this paper, we investigated three aspects of gland function in the noctuid moth Chloridea virescens (Fabricius): (i) whether translocation of pheromone from site of synthesis to release is dependent on calling or ovipositor movement, (ii) whether pheromone synthesis rate limits release and (iii) how intermittent calling (observed in this and other species) might affect the dynamics of release rate. Firstly, by manipulating the gland to simulate calling (extruded) or non-calling (retracted), we showed that pheromone translocation occurred regardless of whether the gland was retracted or extruded. Secondly, by manipulating pheromone production, we found that females that produced more pheromone had higher release rates. It was especially noticeable that females had a higher release rate at the start of calling, which dropped rapidly and leveled off over time. Together, these data suggest that intermittent calling in C. virescens (and other species) may function to allow females to replenish pheromone stores on the gland surface between calling bouts, so that brief, high release rates occur at the start of a calling bout; thus, potentially increasing a female's chances of attracting a mate.

Trail-Following Pheromones in the Termite Subfamily Syntermitinae (Blattodea, Termitoidae, Termitidae).

Trail-following behavior is a key to ecological success of termites, allowing them to orient themselves between the nesting and foraging sites. This behavior is controlled by specific trail-following pheromones produced by the abdominal sternal gland occurring in all termite species and developmental stages. Trail-following communication has been studied in a broad spectrum of species, but the "higher" termites (i.e. Termitidae) from the subfamily Syntermitinae remain surprisingly neglected. To fill this gap, we studied the trail-following pheromone in six genera and nine species of Syntermitinae. Our chemical and behavioral experiments showed that (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol is the single component of the pheromone of all the termite species studied, except for Silvestritermes euamignathus. This species produces both (3Z,6Z)-dodeca-3,6-dien-1-ol and neocembrene, but only (3Z,6Z)-dodeca-3,6-dien-1-ol elicits trail-following behavior. Our results indicate the importance of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol, the most widespread communication compound in termites, but also the repeated switches to other common pheromones as exemplified by S. euamignathus.

Behavioral effect of the specific sex pheromone pH-227-1RR towards butterflies codling moth Cydia pomonella in two apple orchards in draa ben khedda region of north Algeria

Behavioral effect of the specific sex pheromone pH-227-1RR towards butterflies codling moth Cydia pomonella in two apple orchards in draa ben khedda region of north Algeria