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Plants (Basel, Switzerland) May 2024Pollination by sexual deception specifically attracts male insects, through the floral scent and particular morphological features of the flower that serve as visual and...
Osmophore Structure and Labellum Micromorphology in (Orchidaceae): New Interpretations of Floral Features and Implications for a Specific Sexually Deceptive Pollination Interaction.
Pollination by sexual deception specifically attracts male insects, through the floral scent and particular morphological features of the flower that serve as visual and tactile stimuli. The unique bond between the orchid and the male wasp primarily stems from a few distinctive semiochemicals that mimic the female wasp's sex pheromone, although the floral scent comprises a variety of compounds. An osmophore producing highly volatile compounds has been documented in four close relatives of and is now being also investigated in this species. Given the existing debates regarding the structure of the labellum and stigmatic cavity in , this study details their micromorphology. Additionally, comparisons of flowers and female wasps under stereomicroscopy and scanning electron microscopy are conducted to seek new evidence of visual and tactile mimicry. The findings confirm that (i) an osmophore is present at the apical margin of the labellum in flowers; (ii) the labellum features a distinct basal field homologous to those found in other species; and (iii) the basal labellum region closely mimics the female wasp's thorax and wings. The implications of these novel floral features are discussed within an evolutionary context.
PubMed: 38794483
DOI: 10.3390/plants13101413 -
Pathogens (Basel, Switzerland) May 2024In ascomycetous fungi, sexual mate recognition requires interaction of the Ste2 receptor protein produced by one partner with the α-factor peptide pheromone produced by...
In ascomycetous fungi, sexual mate recognition requires interaction of the Ste2 receptor protein produced by one partner with the α-factor peptide pheromone produced by the other partner. In some fungi, Ste2 is further needed for chemotropism towards plant roots to allow for subsequent infection and colonization. Here, we investigated whether this is also true for the pine pitch canker fungus, , which is a devastating pathogen of pine globally. Ste2 knockout mutants were generated for two opposite mating-type isolates, after which all strains were subjected to chemotropism assays involving exudates from pine seedling roots and synthetic α-factor pheromone, as well as a range of other compounds for comparison. Our data show that Ste2 is not required for chemotropism towards any of these other compounds, but, in both wild-type strains, Ste2 deletion resulted in the loss of chemotropism towards pine root exudate. Also, irrespective of mating type, both wild-type strains displayed positive chemotropism towards α-factor pheromone, which was substantially reduced in the deletion mutants and not the complementation mutants. Taken together, these findings suggest that Ste2 likely has a key role during the infection of pine roots in production nurseries. Our study also provides a strong foundation for exploring the role of self-produced and mate-produced α-factor pheromone in the growth and overall biology of the pitch canker pathogen.
PubMed: 38787277
DOI: 10.3390/pathogens13050425 -
Scientific Reports May 2024Most terrestrial mammals have a vomeronasal system to detect specific chemicals. The peripheral organ of this system is a vomeronasal organ (VNO) opening to the incisive...
Most terrestrial mammals have a vomeronasal system to detect specific chemicals. The peripheral organ of this system is a vomeronasal organ (VNO) opening to the incisive duct, and its primary integrative center is an accessory olfactory bulb (AOB). The VNO in seals is thought to be degenerated like whales and manatees, unlike otariids, because of the absence of the AOB. However, olfaction plays pivotal roles in seals, and thus we conducted a detailed morphological evaluation of the vomeronasal system of three harbor seals (Phoca vitulina). The VNO lumen was not found, and the incisive duct did not open into the oral cavity but was recognized as a fossa on the anteroventral side of the nasal cavity. This fossa is rich in mucous glands that secrete acidic mucopolysaccharides, which might originate from the vomeronasal glands. The olfactory bulb consisted only of a main olfactory bulb that received projections from the olfactory mucosa, but an AOB region was not evident. These findings clarified that harbor seals do not have a VNO to detect some chemicals, but the corresponding region is a specialized secretory organ.
Topics: Animals; Vomeronasal Organ; Phoca; Nasal Cavity; Olfactory Bulb; Mucus; Olfactory Mucosa; Male; Smell; Female
PubMed: 38783070
DOI: 10.1038/s41598-024-62711-x -
Advances in Experimental Medicine and... May 2024Lipids are essential in insects and play pleiotropic roles in energy storage, serving as a fuel for energy-driven processes such as reproduction, growth, development,...
Lipids are essential in insects and play pleiotropic roles in energy storage, serving as a fuel for energy-driven processes such as reproduction, growth, development, locomotion, flight, starvation response, and diapause induction, maintenance, and termination. Lipids also play fundamental roles in signal transduction, hormone synthesis, forming components of the cell membrane, and thus are essential for maintenance of normal life functions. In insects, the neuroendocrine system serves as a master regulator of most life activities, including growth and development. It is thus important to pay particular attention to the regulation of lipid metabolism through the endocrine system, especially when considering the involvement of peptide hormones in the processes of lipogenesis and lipolysis. In insects, there are several lipogenic and lipolytic hormones that are involved in lipid metabolism such as insulin-like peptides (ILPs), adipokinetic hormone (AKH), 20-hydroxyecdysone (20-HE), juvenile hormone (JH), and serotonin. Other neuropeptides such as diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN), CCHamide-2, short neuropeptide F, and the cytokines Unpaired 1 and 2 may play a role in inducing lipogenesis. On the other hand, neuropeptides such as neuropeptide F, allatostatin-A, corazonin, leukokinin, tachykinins, limostatins, and insulin-like growth factor (ILP6) stimulate lipolysis. This chapter briefly discusses the current knowledge of the endocrine regulation of lipid metabolism in insects that could be utilized to reveal differences between insects and mammalian lipid metabolism which may help understand human diseases associated with dysregulation of lipid metabolism. Physiological similarities of insects to mammals make them valuable model systems for studying human diseases characterized by disrupted lipid metabolism, including conditions like diabetes, obesity, arteriosclerosis, and various metabolic syndromes.
PubMed: 38782869
DOI: 10.1007/5584_2024_807 -
Parasitology Research May 2024The most widely used attractant to capture adult female mosquitoes is CO. However, there are also baits available on the market that emit a scent resembling human skin.... (Comparative Study)
Comparative Study
The most widely used attractant to capture adult female mosquitoes is CO. However, there are also baits available on the market that emit a scent resembling human skin. These baits were specifically designed to attract highly anthropophilic species such as Aedes albopictus and Aedes aegypti. In this study, we compare the effectiveness of CDC traps baited either with CO or with a commercial blend simulating skin odor, BG-Sweetscent, for trapping female mosquitoes during daylight hours in an urban reserve in the City of Buenos Aires. We employed a hurdle generalized linear mixed model to analyze trap capture probability and the number of mosquitoes captured per hour, considering the effects of attractant, mosquito species, and their interaction. Traps baited with CO captured ten mosquito species, while those baited with BG-Sweetscent captured six in overall significantly lower abundance. The odds of capturing mosquitoes were 292% higher for the CO-baited traps than for those baited with BG-Sweetscent. No evidence of a combined effect of attractant type and species on female mosquito captures per hour was found. Results indicated that CDC traps baited with CO were more effective than those baited with BG-Sweetscent in capturing more mosquito species and a higher number of mosquitoes within each species, even if the species captured with CO exhibited a certain level of anthropophilia. This result has practical implications for mosquito surveillance and control in urban natural reserves.
Topics: Animals; Female; Mosquito Control; Culicidae; Pheromones; Carbon Dioxide; Cities; Odorants; Argentina; Humans
PubMed: 38777889
DOI: 10.1007/s00436-024-08224-y -
Micron (Oxford, England : 1993) Aug 2024Sexual dimorphism in Dyschiriini (Coleoptera, Carabidae) consists of the presence of an autapomorphic sensory area in apical palpomeres of males, here named as Male... (Comparative Study)
Comparative Study
Sexual dimorphism of Dyschiriini (Coleoptera, Carabidae): Comparative morphological SEM study of palpi sensilla and its possible role in intraspecific chemical communication.
Sexual dimorphism in Dyschiriini (Coleoptera, Carabidae) consists of the presence of an autapomorphic sensory area in apical palpomeres of males, here named as Male Palpi Sensory Area (MPSA). In this work, microstructure of palpi, with focus on MPSA, is characterized and formally described using Scanning Electron Microscopy (SEM). Interspecific variability among 13 species and three subgenera of Dyschirius Bonelli, 1810 and one species of Reicheiodes Ganglbauer, 1891 is assessed. Palpi of studied Dyschiriini presented up to 4 sensilla classes (coeloconica, basiconica, digitiformia, trichodea) in both sexes, while males had one more class (sensilla placodea) found grouped in MPSA. Measurements of sensilla and MPSA are provided. Differences among taxa corresponded to development grade of MPSA and its number of sensilla placodea. The MPSA of Dyschirius (Dyschirius) thoracicus Rossi, 1790 were clearly different to the rest of the studied subgenera and species of Dyschirius and Reicheiodes, whose MPSA were similar and had slight intraspecific variability. We suggest that function of MPSA is likely detection of female pheromones, which would evidence chemical communication between sexes. We hypothesize that evolution of MPSA could be related to burrowing habits of Dyschiriini and its possible sexual behavior in soil tunnels. Study of MPSA may help to elucidate phylogenetic relationships among members of the tribe.
Topics: Animals; Coleoptera; Male; Microscopy, Electron, Scanning; Sensilla; Female; Sex Characteristics
PubMed: 38776569
DOI: 10.1016/j.micron.2024.103659 -
PloS One 2024The praying mantis Creobroter nebulosa Zheng (Mantedea: Hymenopodidae) is an insect that has medicinal and esthetical importance, and being a natural enemy for many...
The praying mantis Creobroter nebulosa Zheng (Mantedea: Hymenopodidae) is an insect that has medicinal and esthetical importance, and being a natural enemy for many insects, the species is used as a biological control agent. In this publication, we used scanning electron microscopy (SEM) to study the fine morphology of antennae of males and females of this species. The antennae of both sexes are filiform and consist of three parts: scape, pedicel, and flagellum (differing in the number of segments). Based on the external morphology and the sensilla distribution, the antennal flagellum is could be divided into five regions. Seven sensilla types and eleven subtypes of sensilla were observed: grooved peg sensillum (Sgp), Bohm bristles (Bb), basiconic sensillum (Sb), trichoid sensillum (StI, StII), campaniform sensillum (Sca), chaetic sensillum (ScI, ScII, ScIII), and coeloconic sensillum (ScoI, ScoII). In Mantodea, the ScoII is observed for the first time, and it is located on the tip of the flagellum. The external structure and distribution of these sensilla are compared to those of other insects and possible functions of the antennal sensilla are discussed. The males and females of the mantis could be distinguished by the length of antennae and number of Sgp. Males have antennae about 1.5 times longer and have significantly larger number of Sgp compared to females. The sexual difference in distribution of the Sgp suggests that this type of sensilla may play a role in sex-pheromones detection in mantis.
Topics: Animals; Female; Male; Sensilla; Microscopy, Electron, Scanning; Mantodea; Arthropod Antennae
PubMed: 38771816
DOI: 10.1371/journal.pone.0301445 -
Insect Science May 2024Given the limited availability of resources in nature, sexual attractiveness may trade off with immunocompetence, as the immunocompetence handicap hypothesis (ICHH)...
Given the limited availability of resources in nature, sexual attractiveness may trade off with immunocompetence, as the immunocompetence handicap hypothesis (ICHH) posits. In invertebrates, a direct link between trade-offs through hormonal/molecular effectors in sexual signals and immunity has not been found so far. Here, we assessed how variation in sexual signals affected parasite infection in two sex pheromone selected lines of the moth Chloridea virescens: an attractive line with a low ratio of 16:Ald/Z11-16:Ald and an unattractive line with a high ratio. When infecting these lines with an apicomplexan parasite, we found that the attractive Low line was significantly more susceptible to the parasite infection than the unattractive High line. Since the ratio difference between these two lines is determined by a delta-11-desturase, we hypothesized that this desaturase may have a dual role, i.e., in the quality of the sexual signal as well as an involvement in immune response, comparable to testosterone in vertebrates. However, when we used CRISPR/cas9 to knockout delta-11-desturase in the attractive Low line, we found that the pheromonal phenotype did change to that of the High line, but the infection susceptibility did not. Notably, when checking the genomic location of delta-11-desaturase in the C. virescens, we found that mucin is adjacent to delta-11-desaturase. When comparing the mucin sequences in both lines, we found four nonsynonymous SNPs in the coding sequence, as well as intronic variation between the two lines. These differences suggest that genetic hitchhiking may explain the variation in susceptibility to parasitic infection.
PubMed: 38769890
DOI: 10.1111/1744-7917.13379 -
Journal of Agricultural and Food... Jun 2024(Targioni-Tozzetti) (Hemiptera: Coccoidea: Pseudococcidae), a polyphagous and cosmopolitan pest native to Australia, is a highly damaging pest for numerous crops of...
(Targioni-Tozzetti) (Hemiptera: Coccoidea: Pseudococcidae), a polyphagous and cosmopolitan pest native to Australia, is a highly damaging pest for numerous crops of economic importance. The sex pheromone of this species (2-(1,5,5-trimethylcyclopent-2-en-1-yl)ethyl acetate), currently used for pest monitoring purposes, was not attractive to males in field experiments conducted in Spanish persimmon orchards infested with this mealybug. The virgin and mated female volatile profiles of these populations were studied by the volatile collection of effluvia in Porapak-Q. The resulting extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS), revealing a new compound specific to virgin females and different from the previously described sex pheromone. Based on GC-MS data and nuclear magnetic resonance experiments, we envisaged monoterpene 2-(1,5-dimethyl-4-methylenecyclopent-2-en-1-yl)ethyl acetate as the new sex pheromone candidate, which was synthesized and shown to be attractive in the field to males of the Spanish population.
Topics: Animals; Hemiptera; Sex Attractants; Female; Male; Gas Chromatography-Mass Spectrometry; Spain; Monoterpenes
PubMed: 38769753
DOI: 10.1021/acs.jafc.4c00921 -
Journal of Chemical Ecology May 2024
PubMed: 38767819
DOI: 10.1007/s10886-024-01510-0