Mouth Parts Research Articles

A test of adaptive divergence in a newly discovered host association of the soapberry bugJadera haematolomaon Mexican buckeye,Ungnadia speciosa

AbstractHost races represent an important step in the speciation process of phytophagous insects as they reflect the maintenance of genetically divergent host‐associated populations in the face of appreciable gene flow. The red‐shouldered soapberry bug,Jadera haematoloma(Herrich‐Schäffer) (Hemiptera: Rhopalidae), is an oligophagous seed predator with a history of host race evolution on plant associations in the (soapberry) family Sapindaceae. Soapberry bugs are a model group for understanding rapid ecological adaptation to their hosts, and hence good candidates for investigating evolutionary divergence in host associations over short timescales. Here, we describe the recent discovery of Mexican buckeye,Ungnadia speciosaEndl., as a host ofJ. haematolomain a region of the Chihuahuan desert including west Texas and southeastern New Mexico, USA. This host differs fromJ. haematoloma’s previously recorded hosts in the Sapindaceae in seed chemistry, ecology, and phylogeny. The tendency toward rapid, host‐associated adaptations by populations ofJ. haematolomaand the unique biology of the newly discoveredUngnadiahost create the opportunity for potential host race formation, as it overlaps geographically with two previously recorded host plants in this region – the native western soapberry tree,Sapindus saponariavar.drummondii(Hook & Arn.), and the non‐native goldenrain tree,Koelreuteria paniculataLaxm. We explore the possibility of host race formation onUngnadia‐associated insects by testing for host‐associated differentiation in morphology and feeding behaviors. We find evidence of differentiation in the length of the mouth parts, which is an ecologically relevant feeding trait between host plant species with larger or smaller seed capsules. This divergence is maintained in the face of potential gene flow by reproductive isolation in the form of habitat isolation, which we detect in host preference trials. Together, our results demonstrate that soapberry bugs associated with this newly discovered host exhibit morphological and behavioral traits consistent with host race formation, but additional work is required to confirm its state along the speciation continuum.

Desktop scanning electron microscopy in plant-insect interactions research: a fast and effective way to capture electron micrographs with minimal sample preparation.

The ability to visualize cell and tissue morphology at a high magnification using scanning electron microscopy (SEM) has revolutionized plant sciences research. In plant–insect interactions studies, SEM-based imaging has been of immense assistance to understand plant surface morphology including trichomes [plant hairs; physical defense structures against herbivores], spines, waxes, and insect morphological characteristics such as mouth parts, antennae, and legs, that they interact with. While SEM provides finer details of samples, and the imaging process is simpler now with advanced image acquisition and processing, sample preparation methodology has lagged. The need to undergo elaborate sample preparation with cryogenic freezing, multiple alcohol washes, and sputter coating makes SEM imaging expensive, time consuming, and warrants skilled professionals, making it inaccessible to majority of scientists. Here, using a desktop version of SEM (SNE- 4500 Plus Tabletop), we show that the “plug and play” method can efficiently produce SEM images with sufficient details for most morphological studies in plant–insect interactions. We used leaf trichomes of Solanum genus as our primary model, and oviposition by tobacco hornworm (Manduca sexta; Lepidoptera: Sphingidae) and fall armyworm (Spodoptera frugiperda; Lepidoptera: Noctuidae), and leaf surface wax imaging as additional examples to show the effectiveness of this instrument and present a detailed methodology to produce the best results with this instrument. While traditional sample preparation can still produce better resolved images with less distortion, we show that even at a higher magnification, the desktop SEM can deliver quality images. Overall, this study provides detailed methodology with a simpler “no sample preparation” technique for scanning fresh biological samples without the use of any additional chemicals and machinery.

Nectar Feeding by a Honey Bee's Hairy Tongue: Morphology, Dynamics, and Energy-Saving Strategies.

Simple SummaryThis paper reviews the interdisciplinary research on nectar feeding behaviour of honey bees ranging from morphology, dynamics, and energy-saving strategies, which collects a range of knowledge of feeding physiology of honey bees and may inspire the design paradigms of next-generation multifunctional microfluidic transporters.Most flower-visiting insects have evolved highly specialized morphological structures to facilitate nectar feeding. As a typical pollinator, the honey bee has specialized mouth parts comprised of a pair of galeae, a pair of labial palpi, and a glossa, to feed on the nectar by the feeding modes of lapping or sucking. To extensively elucidate the mechanism of a bee’s feeding, we should combine the investigations from glossa morphology, feeding behaviour, and mathematical models. This paper reviews the interdisciplinary research on nectar feeding behaviour of honey bees ranging from morphology, dynamics, and energy-saving strategies, which may not only reveal the mechanism of nectar feeding by honey bees but inspire engineered facilities for microfluidic transport.

Adaptive shifts underlie the divergence in wing morphology in bombycoid moths.

The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification. Here, we use the sister-families Sphingidae and Saturniidae to answer how the evolution of aerodynamically important traits is linked to clade divergence and through what process(es) these traits evolve. Many agile Sphingidae evolved hover feeding behaviours, while adult Saturniidae lack functional mouth parts and rely on a fixed energy budget as adults. We find that Sphingidae underwent an adaptive shift in wing morphology coincident with life history and behaviour divergence, evolving small high aspect ratio wings advantageous for power reduction that can be moved at high frequencies, beneficial for flight control. By contrast, Saturniidae, which do not feed as adults, evolved large wings and morphology which surprisingly does not reduce aerodynamic power, but could contribute to their erratic flight behaviour, aiding in predator avoidance. We suggest that after the evolution of flapping flight, diversification of wing morphology can be potentiated by adaptative shifts, shaping the diversity of wing morphology across insects.

Effect of the medicinal plant Withania somnifera on the development of a medico-veterinary pest Chrysomya megacephala (Diptera: Calliphoridae)

ABSTRACT Topical administration of root and seed extracts (5, 10, 15 and 20 µg/µL) of Withania somnifera to 0, 1, 2, and 3 days post-moult third instar larvae of Chrysomya megacephala resulted in disruption of moulting and metamorphosis. This leads to several developmental aberrations, such as prolongation of larval-pupal and pupal-adult ecdysis, larval mortality, abnormal pupariation, formation of pupal-adult mosaics and adultoids, ecdysial failure, reduced pupariation and adult emergence. Treatment with seed extracts of W. somnifera was more effective as it causes greater toxicity in all the treated groups as compared to that observed with the root extracts. There was a significant interaction among all three factors viz. extract type (root and seed extracts), larval stage (0, 1, 2, 3 days post-moult third instar larvae) and concentration (5 µg/µL, 10 µg/µL, 15 µg/µL, 20 µg/µL) for prolongation of larval-pupal and pupal-adult ecdysis. The results are similar to those observed with the administration of juvenoids and hence it can be inferred that the plant extracts mimic the action of juvenoids. The results clearly suggest that W. somnifera acts as a potential IGR disrupting the moulting and metamorphosis as a consequence of interference with the normal hormonal mechanism in C. megacephala. Abbreviations: Co Sf=coarse surface; Cy W=cylindrical wings; De Ae = deformed anterior end; De W = deformed wings; Ev G = everted genitalia; Ev Pt = everted ptilinium; L Mp = larval mouth parts; Nm W = non-membranous wings; P Ab = pupal abdomen; P Cu = pupal cuticle; Pa T L = partial tanned legs; Pg E = pigmented eyes; Pm = puparium; Re W = reduced wings; Sr G = scar of genitalia; T Pm = tanned puparium; Tu L = tubular legs; Tw Pm = twisted puparium; Un Ab = untanned abdomen; Un Pm = untanned puparium; W Pri = wing primordia

Face hallucination based on cluster consistent dictionary learning

Face hallucination is a super-resolution technique specially designed to reconstruct high-resolution faces from low-resolution faces. Most state-of-the-art algorithms leverage position-patch prior knowledge of human faces to better super-resolve face images. However, most of them assume the training face dataset is sufficiently large, well cropped or aligned. This paper, proposes a novel example-based face hallucination method, based on cluster consistent dictionary learning with the assumption that human faces have similar facial structures. In this method, the paired face image patches are firstly labelled as face areas including eyes, nose, mouth and other parts, as well as non-face areas without requiring the training face images cropped and aligned. Then, the training patches are clustered according their labels and textures. The cluster consistent dictionary is learned to represent the low-resolution patches and the high-resolution patches. Finally, the high-resolution patches of the input low-resolution face image can be efficiently generated by using the adjusted anchored neighbourhood regression. As utilizing the labelled facial parts prior knowledge, the proposed method represents more details in the reconstruction. Experimental results demonstrate that the authors' algorithm outperforms many state-of-the-art techniques for face hallucination under different datasets.

TOBACCO PRODUCTS: CHEMICAL ANALYSIS AND COMPARATIVE HARMFULNESS

Tobacco consumption is a major social health problem in India as well as throughout the world, because it harms both health and wealth of an addict. Tobacco is a Sthavara Patra Visha received from the plant Nicotiana tobacum/ Nicotiana rusticum leaves by curing them. Tobacco contains an alkaloid nicotine in abundant amount, which is sufficient to make addict like alcohol, cocaine and morphine. There are so many different forms of smoking and smokeless tobacco in India, like cigarette, bidi, gutka, jarda, pan masala etc. Long timed use of Tobacco like adductive products by oral route, acts as a slow poison (Dushi Visha) induces chronic toxicity to the gastrointestinal tract like oral diseases, gingivitis and periodontitis, Leukoplakia (precancerous stage), and may lead to cancer also in advance stage. This chronic toxicity affects cardiovascular system and results as increasing coronary blood flow, heart rate and blood pressure which may trigger the chances of heart attack rate in addict person. Before we can do any effort for reducing toxicity produced by tobacco products its mandatory to knowing the basic knowledge of tobacco products, their chemical composition, their mechanism of action with comparative toxicity and specific tobacco product related to a specific mouth part cancer. Because we can’t stop a person to start tobacco use but we can circulate the knowledge of tobacco products in adolescent groups so that when the beginner chose a tobacco product, he will be aware about the toxicity and affecting organ because of its use. So that, the toxicity can be minimised. Keywords: Tobacco consumption, nicotine, slow poison, cancer, comparative toxicity

Ultra structural study on different sensory structure and some associated body parts of mango mealy bug, Drosicha mangiferae (G.) by scanning electron microscopy

Ultra structural study on different sensory structure and some associated body parts of mango mealy bug, Drosicha mangiferae (G.) by scanning electron microscopy

Why the Mulberry Silkworms (Bombyx mori) are Monophagous and the Cotton Leaf Worms (Spodoptera littorallis) are Polyphagous?

Larvae of order Lepidoptera have biting mouth parts and almost fed on leaves. The insects of Lepidopterous were divided into three groups depended on number of the host plants, the monophagous, the oligophagous and the polyphagous. Sense organs are responsible for the number of host plants and insects select for hosts to fed on. In this study, the head capsule of larvae was cut at the end of larval stage of the mulberry silkworms and the cotton leaf worms to examine by scanning electron microscope for the number and type of sense organs on head capsule of larvae of both insects. The total number of sense organs on the head capsule of the mulberry silkworm was 82 where they were more than that of the cotton leaf worm where they were only38 sense organs. In addition, When mouth parts of the mulberry silk worm were covered with nail polish then the larvae were offered five different species of plant leaves ,Abelmoschus esculentus (okra), Vitis vinifera (grapes), Ricinus communis (castor bean plant),Cucurbita moschata (Pumpkin) and Morus alba (mulberry) to fed on. The treated larvae couldn’t recognize mulberry leaves to feed on. The larvae fed on small part of grapes and okra leaves then stopped to continue feeding. Vomiting and diarrhea were happened to larvae then died.

A diachronic study of the Mediterranean coastline: A geometric approach

Coastal areas represent one of the country's most important environmental and economic resources. They are naturally dynamic, with changes that can occur on a human time scale and that need to be quantified for the proper management of shorelines and, in particular, the beaches on which the local economy is largely based. This work focuses on the diachronic study of the coastline of the Mediterranean coast, particularly the coastal fringe at the mouth of the Wadi Aliane. In order to assess and remedy the risks of erosion and accretion of the coastline, the methodology followed consists of the application of automatic analytical techniques using multi-temporal photo-interpretation, a Geographic Information System (GIS) and a Digital Shoreline Analysis System (DSAS). The rate of change will be calculated from the multi-date maps, (1981- 1997 and 2016) using the End Point Rate (EPR) index. Comparison of the results of the interpretation of aerial photos and satellite images of the Oued Aliane coastline used (1981, 1997, and 2016) provided information that allowed us to understand the evolutionary behaviour of the wet sand/dry sand line over 36 years. This numerical analysis of the 1981 -1997 and 2016 coastlines in the coastal sector of Oued Aliane, shows us that zones A, C and D are mainly affected by erosion, while the mouth part is affected by accretion because it is considered a delta and therefore a sedimentation area.

Role of Tension in Skin Scarring

Skin scarring is a natural process of healing and represents a massive burden on individuals and societies .Scars appear due to sealing of an open skin that occurs more quickly than the normal skin growing process. Depending on the place where scars form, people may suffer severe issues like not able to bend their joints, open or close their mouth parts and lastly suffer from social stigma. A scar is not bad if it is small, not visible or easy to heal. But it is astonishing that recent researches have opened up new ways for us to treat scars instead of hiding them under clothes.
 Recently, scientists suggested the critical role of tension during process of scarring. They observed that early in the fetal developmental stage, when the skin is more gelatinous (less tight), the skin injury does not lead to scarring and likewise, at the older age (95 years) scarring is minimal due to less tightening of skin. Now, the questions arise; why and how tension in the skin induces scar formation during healing?
 The gene named "engrailed" helps produce a protein (sometimes found in fibroblast; a skin cell) that stimulates scar formation. Researchers observed that fibroblasts did not expressed engrailed when grown on tension-free gel; but the expression occurs when grown on stress-inducing plastic. In the later case, inhibition in expression of engrailed was observed after addition of a chemical which inhibit mechanical strain signaling. Similarly, a number of studies in mice suggested crucial role of tension in induction of scarring.
 For a successful wound healing therapy, three outcomes are important to be true skin regeneration; appearance of normal hair follicles and glands, normal epidermal appearance under microscope and regenerated skin needs to be as strong as normal skin. Concurrent to these outcomes, scientists are working with mice by blocking mechanical stress signals with U.S approved drugs and waiting for next stage with pre-clinical trials with other mammalian species.
 In summary, with the rising social and financial burdens of scarring, advancements in the research inspire novel therapies to tackle outcomes of scar formation. Recent studies focus on the role of mechanical forces during scarring whereas, clinical trials favor minimizing tension may led to minimal scar formation. However, tension free therapies for scar reduction persist various limitations and sometimes, not applicable. It is also noteworthy that considerable differences between the mouse and human skin may limit the applications of clinical findings.

A Redescription of the Bulla, Antennae, and Mouth Parts of Female Clavella sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) Infesting Wild Gadus morhua Using Scanning Electron Microscopy (SEM).

Many members of the Copepod family Lernaeopodidae are well-known parasites of gadids. This study reports on the occurrence of a lernaeopodid infestation of wild-sourced Gadus morhua sampled from separate inshore (Gilbert Bay, NL) and offshore (Virgin Rocks, NL) populations from Newfoundland, Canada. The majority of the parasites were observed to be associated with the buccal cavity, gill filaments, gill arch, and occasionally near the outer edge of the operculum. Anatomical analysis and detailed redescriptions of the parasite's functional anatomy (mouth parts, antennae, and bulla complex) using high-resolution SEM indicated that the parasite was most likely of the genus Clavella. New morphological details of the second antennae ornamentation, first maxillae, bulla complex, and the oral cone are provided and discussed with regard to their potential in taxonomic applications.

Negative Mood States Are Related to the Characteristics of Facial Expression Drawing: A Cross-Sectional Study.

An assessment of mood or emotion is important in developing mental health measures, and facial expressions are strongly related to mood or emotion. This study thus aimed to examine the relationship between levels of negative mood and characteristics of mouth parts when moods are drawn as facial expressions on a common platform. A cross-sectional study of Japanese college freshmen was conducted, and 1,068 valid responses were analyzed. The questionnaire survey consisted of participants’ characteristics, the Profile of Mood States (POMS), and a sheet of facial expression drawing (FACED), and the sheet was digitized and analyzed using an image-analysis software. Based on the total POMS score as an index of negative mood, the participants were divided into four groups: low (L), normal (N), high (H), and very high (VH). Lengths of drawn lines and between both mouth corners were significantly longer, and circularity and roundness were significantly higher in the L group. With increasing levels of negative mood, significant decreasing trends were observed in these lengths. Convex downward and enclosed figures were significantly predominant in the L group, while convex upward figures were significantly predominant and a tendency toward predominance of no drawn mouths or line figures was found in the H and VH groups. Our results suggest that mood states can be significantly related to the size and figure characteristics of drawn mouths of FACED on a non-verbal common platform. That is, these findings mean that subjects with low negative mood may draw a greater and rounder mouth and figures that may be enclosed and downward convex, while subjects with a high negative mood may not draw the line, or if any, may draw the line shorter and upward convex.

SCREENING, IDENTIFICATION AND ISOLATION OF SOME FUNGAL SPECIES AGAINST OPPORTUNISTIC FUNGAL PATHOGEN CANDIDA ALBICANS

Candida albicans or Monilia albicans is an opportunistic fungus, it is basically present on the skin and mucous membranes such like vaginal area, mouth, or rectum part. Candida albicans can travel through the blood and affects intestines, throat, and heart valves of healthy as well as immunocompromised individual. When is there is any change in body temperature Candida albicans becomes an infectious agent and it starting grow out of control it also cause life threating infections to patients with weak immunity (AIDS), patients in ICU and undergoing Chemotherapy. Some of the Candida infections could be treated with home remedies, topical creams or with prescription medication such as clotrimazole, miconazole, nystatin, tioconazole, or oral administration of drugs such as fluconazole and amphotericin B. Although all this antifungal drug helps in getting cure the trouble, but the infection can recur. As per the ongoing research on all over the globe, it has been proven that Candida albicans become resistant over most the drug, so it is necessary to find an alternative drug to cure this life-threatening organism. In the present study we evaluated and screened the secondary metabolites of fungi for the control of Candida albicans by evaluating the potential of fungal bioactive compounds, its purification and characterization.

Удосконалення лікувально-евакуаційних заходів у Десантно-штурмових військах Збройних Сил України в умовах збройного конфлікту

Мета. Наукове обґрунтування удосконалення системи ЛЕЗ у ДШВ ЗС України через приведення організаційно-штатної структури медичних підрозділів частин ДШВ у відповідність до специфічних умов діяльності цього роду військ в умовах збройного конфлікту.
 Методи дослідження. Проаналізований розподіл локалізації поранень у тактичних підрозділах СВ ЗС України в зоні проведення АТО/ООС протягом 2017-2018 рр. На підставі звітів та заповнених польових медичних карток (ПМК) Ф-300 (n=114), була зібрана та проаналізована інформація щодо локалізації поранень у військовослужбовців ДШВ ЗС України (79 і 95 Окремі десантно-штурмові бригади та 25 Окрема повітряно-десантна бригада) в зоні проведення АТО/ООС за той же період, а також у підрозділах ДШВ, що приймали участь у рейдових діях протягом 2014 р. Методологія дослідження базувалася на системному підході. Для вирішення поставлених завдань застосовувались наступні методи: системного аналізу (системно-історичний, системно-структурний, системно-комунікативний) та методи статистичного аналізу. При обробці результатів досліджень використовувалися методика φ – Фішера, критерії χ² – Пірсона і t – Стьюдента. 
 Результати. При порівняльному аналізі розподілу локалізації поранень під час проведення рейдових дій підрозділами ДШВ, з’ясувалось, що він відрізняється від такого розподілу у тактичних підрозділах СВ і ДШВ в зоні проведення АТО/ООС із статистично значущим (рα (t, df)≤0,05) переважанням поранень голови і кінцівок, причому шанс отримати поранення голови (при розрахунку відношення шансів) у цього контингенту за таких умов збільшується у 1,3 рази, що викликано принципово іншою бойовою обстановкою, способами і методами ведення бойових дій. Це акцентує увагу на необхідності наявності хірургічної та анестезіологічної компоненти при наданні медичної допомоги в підрозділах і частинах ДШВ при виконанні специфічних завдань в умовах ізоляції та автономного функціонування. 
 Висновки. Необхідною умовою для успішного виконання завдань, притаманних ДШВ ЗС України (десантно-рейдові, десантно-ударні, десантно-штурмові дії, дії в умовах десантування) є удосконалення системи ЛЕЗ шляхом приведення організаційно-штатної структури медичних підрозділів частин цього роду військ у відповідність до специфічних умов діяльності, шляхом підсилення їх лікарями-спеціалістами, які можуть повноцінно надавати первинну та елементи вторинної медичної допомоги. Ця ідея в ході виконання роботи була реалізована в практичну площину, шляхом розробки і затвердження відповідної Директиви ГШ ЗС України (2018 р.), з введенням в штати медичних рот частин ДШВ лікарів-хірургів і лікарів-анестезіологів, що є особливо актуальним в умовах ізоляції та автономного функціонування підрозділів ДШВ при виконанні специфічних бойових завдань.

Digestive activity and organic compounds of Nezara viridula watery saliva induce defensive soybean seed responses

The stink bug Nezara viridula is one of the most threatening pests for agriculture in North and South America, and its oral secretion may be responsible for the damage it causes in soybean (Glycine max) crop. The high level of injury to seeds caused by pentatomids is related to their feeding behavior, morphology of mouth parts, and saliva, though information on the specific composition of the oral secretion is scarce. Field studies were conducted to evaluate the biochemical damage produced by herbivory to developing soybean seeds. We measured metabolites and proteins to profile the insect saliva in order to understand the dynamics of soybean-herbivore interactions. We describe the mouth parts of N. viridula and the presence of metabolites, proteins and active enzymes in the watery saliva that could be involved in seed cell wall modification, thus triggering plant defenses against herbivory. We did not detect proteins from bacteria, yeasts, or soybean in the oral secretion after feeding. These results suggest that the digestive activity and organic compounds of watery saliva may elicit a plant self-protection response. This study adds to our understanding of stink bug saliva plasticity and its role in the struggle against soybean defenses.

Identification and characterization of odorant binding proteins in the diamondback moth, Plutella xylostella.

Odorant binding proteins (OBPs) are a group of soluble proteins functioning as odorant carriers in insect antennae, mouth parts and other chemosensory organs. However, multiple insect OBPs have been detected in other tissues and various functions have been proposed. Therefore, a detailed expression profile including stages, tissues and sexes where OBPs are expressed will assist in building the links to their potential functions, enhancing the functional studies of insect OBPs. Here, we identified 39 putative OBP genes from its genome and transcriptome sequences of diamondback moth (DBM), Plutella xylostella. The expression patterns of identified PxylOBPs were further investigated from eggs, larvae, pupae, virgin adults, mated adults, larval midgut, larval heads, adult antennae, adult heads and adult tarsi. Moreover, P. xylostella larvae and adults with and without host plants for 5h were utilized to study the interactions between OBP expression and host plants. The results showed that most PxylOBPs were highly expressed in male and female adult antennae. The expression levels of certain PxyOBPs could be regulated by mating activities and feeding host plants. This study advances our knowledge of P. xylostella OBPs, which may help develop new strategies for more environmentally sustainable management of P. xylostella.

Oxygen Regime of the Channel Flow in the Small Maima River, Upper Ob Basin

The oxygen regime of the channel flow of the small Maima River (Upper Ob basin) has been considered. A study of the spatial and seasonal variations of oxygen regime characteristics in the mouth part of the river and its tributaries has shown that they vary from their sources to the mouths. The effect of the industrial–residential agglomeration of Gorno-Altaisk on surface water quality in the region has been assessed. The oxygen regime was found to deteriorate from large to small rivers and their tributaries. An integral index of surface runoff by oxygen regime characteristics is proposed: high quality (low-pollution water)―less than 10 units, medium quality (polluted water)―10–30 units, and low quality (polluted water)―more than 30 units.

Cucurbitacin B Activates Bitter-Sensing Gustatory Receptor Neurons via Gustatory Receptor 33a in Drosophila melanogaster.

The Gustatory system enables animals to detect toxic bitter chemicals, which is critical for insects to survive food induced toxicity. Cucurbitacin is widely present in plants such as cucumber and gourds that acts as an anti-herbivore chemical and an insecticide. Cucurbitacin has a harmful effect on insect larvae as well. Although various beneficial effects of cucurbitacin such as alleviating hyperglycemia have also been documented, it is not clear what kinds of molecular sensors are required to detect cucurbitacin in nature. Cucurbitacin B, a major bitter component of bitter melon, was applied to induce action potentials from sensilla of a mouth part of the fly, labellum. Here we identify that only Gr33a is required for activating bitter-sensing gustatory receptor neurons by cucurbitacin B among available 26 Grs, 23 Irs, 11 Trp mutants, and 26 Gr-RNAi lines. We further investigated the difference between control and Gr33a mutant by analyzing binary food choice assay. We also measured toxic effect of Cucurbitacin B over 0.01 mM range. Our findings uncover the molecular sensor of cucurbitacin B in Drosophila melanogaster. We propose that the discarded shell of Cucurbitaceae can be developed to make a new insecticide.

Morphological variation associated with trophic niche expansion within a lake population of a benthic fish

Ecological theory suggests that generalist species should have traits with multiple adaptive peaks. Consequently, in heterogeneous environments such adaptive landscapes may lead to phenotypic divergence that becomes fixed in populations via reproductive isolation, thus driving speciation. However, contrary to this expectation, the process of ecological diversification in wild populations is not always associated with obvious trait divergence and reproductive isolation due to some ecological and geographic constrains. To examine the ecological conditions that promote (or inhibit) divergence is quite important to improve our understanding of the underlying mechanisms. Here we examine how the patterns of trait variation (divergence/non-divergence) are determined in relation to ecological niche expansion and gene flow using a benthic fish, Pseudogobio esocinus, in the Lake Biwa system, Japan. The fish exhibited various patterns of morphological variation in mouth parts among populations. Lake fish tended to have a smaller mouth compared with river fish and also showed remarkable individual variations within some local samples. Lake fish utilized chironomid larvae as the primary prey, as in riverine fish. But, fish with smaller and narrower mouths utilized significantly higher proportions of amphipods (a novel prey unique to the lake) as their secondary prey. Microsatellite analysis detected no genetic structuring in the Lake Biwa catchment, suggesting no reproductive separation among eco-morphologically divergent individuals. Our results exemplify population niche expansion associated with continuous eco-morphological variation without divergence, and provide insights into the role of non-discrete diversification for thriving in heterogeneous environments.