RESUMO
Visually guided reaching, a regular feature of human life, comprises an intricate neural control task. It includes identifying the target's position in 3D space, passing the representation to the motor system that controls the respective appendages, and adjusting ongoing movements using visual and proprioceptive feedback. Given the complexity of the neural control task, invertebrates, with their numerically constrained central nervous systems, are often considered incapable of this level of visuomotor guidance. Here, we provide mechanistic insights into visual appendage guidance in insects by studying the probing movements of the hummingbird hawkmoth's proboscis as they search for a flower's nectary. We show that visually guided proboscis movements fine-tune the coarse control provided by body movements in flight. By impairing the animals' view of their proboscis, we demonstrate that continuous visual feedback is required and actively sought out to guide this appendage. In doing so, we establish an insect model for the study of neural strategies underlying eye-appendage control in a simple nervous system.
Assuntos
Movimento , Desempenho Psicomotor , Animais , Humanos , Desempenho Psicomotor/fisiologia , Movimento/fisiologia , Insetos , Retroalimentação Sensorial/fisiologia , Percepção Visual/fisiologiaRESUMO
Viral infections can be detrimental to the foraging ability of the western honey bee, Apis mellifera. The deformed wing virus (DWV) is the most common honey bee virus and has been proposed as a possible cause of learning and memory impairment. However, evidence for this phenomenon so far has come from artificially infected bees, while less is known about the implications of natural infections with the virus. Using the proboscis extension reflex (PER), we uncovered no significant association between a simple associative learning task and natural DWV load. However, when assessed through a reversal associative learning assay, bees with higher DWV load performed better in the reversal learning phase. DWV is able to replicate in the honey bee mushroom bodies, where the GABAergic signalling pathway has an antagonistic effect on associative learning but is crucial for reversal learning. Hence, we assessed the pattern of expression of several GABA-related genes in bees with different learning responses. Intriguingly, mushroom body expression of selected genes was positively correlated with DWV load, but only for bees with good reversal learning performance. We hypothesise that DWV might improve olfactory learning performance by enhancing the GABAergic inhibition of responses to unrewarded stimuli, which is consistent with the behavioural patterns that we observed. However, at higher disease burdens, which might be induced by an artificial infection or by a severe, natural Varroa infestation, this DWV-associated increase in GABA signalling could impair associative learning as previously reported by other studies.
Assuntos
Corpos Pedunculados , Vírus de RNA , Animais , Abelhas/virologia , Abelhas/fisiologia , Corpos Pedunculados/virologia , Corpos Pedunculados/fisiologia , Vírus de RNA/fisiologia , Transdução de Sinais , Reversão de Aprendizagem/fisiologia , Aprendizagem por Associação/fisiologiaRESUMO
BACKGROUND: One of the constrain in proboscis monkey (Nasalis larvatus) conservation is gastrointestinal helminth (GH) infection. Here, we conducted a study to determine the prevalence of GHs in captive proboscis monkeys in Surabaya Zoo, Indonesia. METHODS: Twenty fecal samples were collected from three groups (i.e., nursery cage [NC] [n = 1], communal show cage [SC] [n = 8], and free-ranging colonies [FC] [n = 11]). The fecal samples have been examined through McMaster and sugar floatation techniques. RESULTS: The total prevalence of GH infection was 85.00% (17/20). We confirmed infection of Trichuris sp., Ascaris sp., Strongyloides sp., and Hymenolepis nana with Trichuris eggs was dominant. Although the prevalence of infection was high, the number of eggs per gram (epg) was low. CONCLUSION: GH infection in captive proboscis monkeys in Surabaya Zoo, Indonesia, is highly prevalent. These results were useful for future research, control, and prevention of zoonotic potency purposes.
Assuntos
Animais de Zoológico , Helmintíase Animal , Doenças dos Macacos , Animais , Indonésia/epidemiologia , Helmintíase Animal/epidemiologia , Helmintíase Animal/parasitologia , Doenças dos Macacos/parasitologia , Doenças dos Macacos/epidemiologia , Prevalência , Fezes/parasitologia , Colobinae/parasitologia , Feminino , Masculino , PresbytiniRESUMO
Whether in ant-aphid mutualism the ants exert evolutionary selection pressure on aphid morphology has not yet been fully tested. Here, we tested whether the long proboscises of Stomaphis yanonis (Aphididae Lachninae) aphids confer an advantage in preventing predation by the tending ants. Specifically, we tested the hypothesis that aphids with a shorter proboscis would excrete less honeydew, making them more likely to be preyed upon by ants. Our results showed that aphid individuals with a shorter proboscis took up less phloem sap and excreted less honeydew than individuals with a longer proboscis. In addition, among aphids with a similar body size, those with a shorter proboscis were more susceptible to predation by ants than those with a longer proboscis. These results suggest that predation by tending ants, by exerting selection pressure on aphid proboscis morphology, has caused the aphids to evolve longer proboscises.
Assuntos
Formigas , Afídeos , Comportamento Predatório , Animais , Afídeos/fisiologia , Formigas/fisiologia , Comportamento Predatório/fisiologia , Simbiose/fisiologiaRESUMO
Bee populations are facing numerous stressors globally, including environmental pollution by trace metals and metalloids. Understanding whether bees can detect and avoid these pollutants in their food is pivotal, as avoidance abilities may mitigate their exposure to xenobiotics. While these pollutants are known to induce sublethal effects in bees, such as disrupting physiological mechanisms, their potential impacts on locomotive abilities, fat metabolism, and reproductive physiology remain poorly understood. In this study, utilising workers of the buff-tailed bumble bee and two prevalent trace metals, namely cadmium and copper, we aimed to address these knowledge gaps for field-realistic concentrations. Our findings reveal that workers did not reject field-realistic concentrations of cadmium and copper in sucrose solutions. Moreover, they did not reject lethal concentrations of cadmium, although they rejected lethal concentrations of copper. Additionally, we observed no significant effects of field-realistic concentrations of these metals on the walking and flying activities of workers, nor on their fat metabolism and reproductive physiology. Overall, our results suggest that bumble bees may not avoid cadmium and copper at environmental concentrations, but ingestion of these metals in natural settings may not adversely affect locomotive abilities, fat metabolism, or reproductive physiology. However, given the conservative nature of our study, we still recommend future research to employ higher concentrations over longer durations to mimic conditions in heavily polluted areas (i.e., mine surrounding). Furthermore, investigations should ascertain whether field-realistic concentrations of metals exert no impact on bee larvae.
Assuntos
Cádmio , Cobre , Animais , Abelhas/fisiologia , Abelhas/efeitos dos fármacos , Cobre/toxicidade , Cádmio/toxicidade , Poluentes Ambientais/toxicidadeRESUMO
Habituated animals retain a latent capacity for robust engagement with familiar stimuli. In most instances, the ability to override habituation is best explained by postulating that habituation arises from the potentiation of inhibitory inputs onto stimulus-encoding assemblies and that habituation override occurs through disinhibition. Previous work has shown that inhibitory plasticity contributes to specific forms of olfactory and gustatory habituation in Drosophila Here, we analyze how exposure to a novel stimulus causes override of gustatory (proboscis extension reflex; PER) habituation. While brief sucrose contact with tarsal hairs causes naive Drosophila to extend their proboscis, persistent exposure reduces PER to subsequent sucrose stimuli. We show that in so habituated animals, either brief exposure of the proboscis to yeast or direct thermogenetic activation of sensory neurons restores PER response to tarsal sucrose stimulation. Similar override of PER habituation can also be induced by brief thermogenetic activation of a population of tyrosine hydroxylase (TH)-positive neurons, a subset of which send projections to the subesophageal zone (SEZ). Significantly, sensory-neuron induced habituation override requires transmitter release from these TH-positive cells. Treatments that cause override specifically influence the habituated state, with no effect on the naive sucrose response across a range of concentrations. Taken together with other findings, these observations in female flies are consistent with a model in which novel taste stimuli trigger activity in dopaminergic neurons which, directly or indirectly, inhibit GABAergic cells that drive PER habituation. The implications of these findings for general mechanisms of attentional and sensory override of habituation are discussed.SIGNIFICANCE STATEMENT Habituation can be overcome when a new context requires an enhanced response to a familiar stimulus. However, the underlying mechanisms remain incompletely understood. Previous studies have provided evidence that habituation of the sucrose-induced proboscis extension reflex (PER) in Drosophila occurs through potentiation of inhibition onto the PER pathway. This work defines controlled protocols for override of PER habituation and uses them to outline the underlying circuit mechanisms. The results presented support a model in which novel taste stimuli cause dishabituation by activating a subset of tyrosine hydroxylase (TH)-expressing neurons that inhibit GABAergic neurons whose potentiation underlies PER habituation. At a general level, these findings further highlight a central role for inhibition and disinhibition in the control of behavioral flexibility.
Assuntos
Drosophila , Habituação Psicofisiológica , Animais , Drosophila/fisiologia , Feminino , Neurônios GABAérgicos/metabolismo , Habituação Psicofisiológica/fisiologia , Células Receptoras Sensoriais/metabolismo , Sacarose/farmacologia , Tirosina 3-Mono-OxigenaseRESUMO
PREMISE: Many flowering plants depend on insects for pollination and thus attract pollinators by offering rewards, mostly nectar and pollen. Bee pollinators rely on pollen as their main nutrient source. Pollen provides all essential micro- and macronutrients including substances that cannot be synthesized by bees themselves, such as sterols, which bees need for processes such as hormone production. Variations in sterol concentrations may consequently affect bee health and reproductive fitness. We therefore hypothesized that (1) these variations in pollen sterols affect longevity and reproduction in bumble bees and (2) can thus be perceived via the bees' antennae before consumption. METHODS: We studied the effect of sterols on longevity and reproduction of Bombus terrestris workers in feeding experiments and investigated sterol perception using chemotactile proboscis extension response (PER) conditioning. RESULTS: Workers could perceive several sterols (cholesterol, cholestenone, desmosterol, stigmasterol, ß-sitosterol) via their antennae but not differentiate between them. However, when sterols were presented in pollen, and not as a single compound, the bees were unable to differentiate between pollen differing in sterol content. Additionally, different sterol concentrations in pollen neither affected pollen consumption nor brood development or worker longevity. CONCLUSIONS: Since we used both natural concentrations and concentrations higher than those found in pollen, our results indicate that bumble bees may not need to pay specific attention to pollen sterol content beyond a specific threshold. Naturally encountered concentrations might fully support their sterol requirements and higher concentrations do not seem to have negative effects.
Assuntos
Fitosteróis , Abelhas , Animais , Reprodução , Esteróis , Pólen , PercepçãoRESUMO
BACKGROUND: Proboscis lateralis (PL) is an uncommon congenital facial deformity marked by the protrusion of a primitive tubular structure made up of skin and soft tissue that generally emerges from the eye's medial canthus and is associated with some craniofacial deformities. We report the first case of PL with multiple craniofacial, neurological, cardiac, and spinal anomalies. CASE PRESENTATION: A full-term female baby delivered by cesarean section cried immediately at birth. The mother reported having a normal pregnancy but has a history of x-ray during her first trimester. The baby was born with a rare presentation of proboscis lateralis which was accompanied by multiple anomalies, including but not limited to bilateral colpocephaly, corpus callosum agenesis, complex cyanotic congenital heart disease, and hemivertebra of the T10 body. CONCLUSION: PL is an uncommon congenital condition that causes a variety of craniofacial abnormalities. Multiple additional defects affecting various organ systems should also be evaluated in a person diagnosed with PL.
Assuntos
Anormalidades Múltiplas , Anormalidades Craniofaciais , Gravidez , Lactente , Recém-Nascido , Humanos , Feminino , Nariz/anormalidades , Cesárea , Face , Anormalidades Craniofaciais/diagnóstico , Anormalidades Craniofaciais/diagnóstico por imagemRESUMO
Inositol depletion has been associated with diabetes and related complications. Increased inositol catabolism, via myo-inositol oxygenase (MIOX), has been implicated in decreased renal function. This study demonstrates that the fruit fly Drosophila melanogaster catabolizes myo-inositol via MIOX. The levels of mRNA encoding MIOX and MIOX specific activity are increased when fruit flies are grown on a diet with inositol as the sole sugar. Inositol as the sole dietary sugar can support D. melanogaster survival, indicating that there is sufficient catabolism for basic energy requirements, allowing for adaptation to various environments. The elimination of MIOX activity, via a piggyBac WH-element inserted into the MIOX gene, results in developmental defects including pupal lethality and pharate flies without proboscises. In contrast, RNAi strains with reduced levels of mRNA encoding MIOX and reduced MIOX specific activity develop to become phenotypically wild-type-appearing adult flies. myo-Inositol levels in larval tissues are highest in the strain with this most extreme loss of myo-inositol catabolism. Larval tissues from the RNAi strains have inositol levels higher than wild-type larval tissues but lower levels than the piggyBac WH-element insertion strain. myo-Inositol supplementation of the diet further increases the myo-inositol levels in the larval tissues of all the strains, without any noticeable effects on development. Obesity and blood (hemolymph) glucose, two hallmarks of diabetes, were reduced in the RNAi strains and further reduced in the piggyBac WH-element insertion strain. Collectively, these data suggest that moderately increased myo-inositol levels do not cause developmental defects and directly correspond to reduced larval obesity and blood (hemolymph) glucose.
Assuntos
Drosophila melanogaster , Inositol Oxigenase , Animais , Inositol Oxigenase/genética , Inositol Oxigenase/metabolismo , Drosophila melanogaster/genética , Inositol/metabolismo , Glucose/metabolismo , Obesidade/metabolismo , RNA MensageiroRESUMO
Proboscis lateralis is a rare craniofacial anomaly in which a rudimentary nasal appendage arises at the medial canthal area. The severity depends on organ involvement, including eyes, nose, cleft lip/palate, and/or concomitant intracranial anomalies. Here, we present a child with proboscis lateralis and associated trans-ethmoidal encephalocele. We suggest doing the preoperative CT and/or MRI to rule out associated intracranial anomalies and reliably preoperative planning tools. Moreover, we proposed an alternative nasal reconstructive technique using a composite graft from the proboscis mass at the same time as encephalocele repair with promising results.
Assuntos
Anormalidades Múltiplas , Fenda Labial , Fissura Palatina , Doenças Nasais , Anormalidades do Sistema Respiratório , Criança , Humanos , Anormalidades Múltiplas/cirurgia , Fenda Labial/diagnóstico por imagem , Fenda Labial/cirurgia , Fenda Labial/complicações , Fissura Palatina/cirurgia , Encefalocele/diagnóstico por imagem , Encefalocele/cirurgia , Encefalocele/complicações , Nariz/diagnóstico por imagem , Nariz/cirurgia , Nariz/anormalidadesRESUMO
Lateral proboscis is a rare congenital condition characterized by a cylindrical protuberance on the nasofrontal region accompanied by abnormal nasal development on the affected side. We aimed to describe the management of the lateral proboscis in staged repair. A 7-year-old girl came with a tube-like projection on the left medial canthal region and nasal agenesis on the ipsilateral side. She was diagnosed with lateral proboscis, left microphthalmia, lower eye lid coloboma, and asymmetry in the orbital region. The patient has undergone 3 major surgeries at our institution. The first surgery involved the deconstruction of the tube to form the left nasal body and nostril. The second operation involved trimming of the new nose form and the excision of the bony protrusion directly beneath the base of the pedicle through bifrontal craniotomy. The remaining bone defect was closed using a pericranial flap. The orbital floor was reconstructed using titanium mesh. The third operation involved nasal reconstruction using a costal cartilage graft to create a dorsal nasal and alar framework. The patient healed with no complications, had become less reserved and her grades improved significantly after the operation. Further appointments are being scheduled to evaluate growth distortion and the resulting facial asymmetry. Surgical correction will be planned thereafter to further reconstruct the facial features. Evaluation of patient is necessary to explore possible clinical outcomes and corresponding treatment options. Multidisciplinary management is highly recommended, involving plastic surgeons, neurosurgeons, ophthalmologists, pediatricians, and pediatric psychiatrists in order to improve patient's quality of life.
Assuntos
Doenças Nasais , Anormalidades do Sistema Respiratório , Rinoplastia , Humanos , Criança , Feminino , Qualidade de Vida , Nariz/anormalidades , Doenças Nasais/cirurgia , Cavidade Nasal/cirurgia , Retalhos Cirúrgicos , Rinoplastia/métodosRESUMO
Global warming has been identified as a key driver of bee declines around the world. While it is clear that elevated temperatures during the spring and summer months-the principal activity period of many bee species-is a factor in this decline, exactly how temperature affects bee survival is unknown. In vertebrates, there is clear evidence that elevated ambient temperatures impair cognition but whether and how heat affects the cognitive abilities of invertebrates remains unclear. Cognitive skills in bees are essential for their survival as, to supply the hive with nutrition, workers must be able to learn and remember the location of the most rewarding floral resources. Here, we investigate whether temperature-related cognitive impairments could be a driver of bee declines by exploring the effect of short-term increases in ambient temperature on learning and memory. We found that, in comparison to bees that were tested at 25°C (a temperature that they would typically experience in summer), bees that were exposed to 32°C (a temperature that they will becoming increasingly exposed to during heatwave events) were significantly worse at forming an association between a coloured light and a sucrose reward and that their capacity to remember this association after just 1 h was abolished. This study provides novel experimental evidence that even just a few hours of exposure to heatwave-like temperatures can severely impair the cognitive performance of insects. Such temperature-induced cognitive deficits could play an important role in explaining recent and future bee population declines.
Assuntos
Aprendizagem , Animais , Abelhas , TemperaturaRESUMO
Morphological trait-matching and species abundance are thought to be the main factors affecting the frequency and strength of mutualistic interactions. However, the relative importance of trait-matching and species abundance in shaping species interactions across environmental gradients remains poorly understood, especially for plant-insect mutualisms involving generalist species. Here, we characterised variation in species and trait composition and the relative importance of trait-matching and species abundance in shaping plant-Hymenoptera and plant-Diptera mutualisms in four meadows across an elevational gradient (2,725-3,910 m) in Yulong Snow Mountain, Southwest China. We also evaluated the effects of morphological traits of flower visitors and plant composition on their foraging specialisation (d' and normalised degree). There was a high degree of dissimilarity in the composition of Hymenoptera and Diptera visitors and their visited plants between communities. This variation was mainly driven by the spatial replacement of species. Both for plant-Hymenoptera and plant-Diptera networks, trait-matching between nectar tube depth and proboscis length was a stronger predictor of the interactions between temporally co-occurring plants and flower visitors than species abundance. Fourth-corner analyses revealed statistically significant trait-matching between nectar tube depth and proboscis length in plant-Hymenoptera networks at all sites, suggesting that Hymenoptera consistently foraged on plant species with nectar tube depths matching their proboscis lengths. By contrast, significant trait-matching in plant-Diptera networks was only observed at the two lower elevation sites. The species-level specialisation d' of flower visitors increased significantly as the proboscis length and the difference in nectar tube depth between the plant community and the plants visited by flower visitors increased. Our results highlight that the importance of trait-matching in shaping pairwise interactions and niche partitioning depends on the specific features (e.g. species composition and trait availability) of the plant-pollinator system. For specialised plant-Hymenoptera systems, trait-matching is an important determinant of species interactions, whereas for generalist plant-Diptera systems, trait-matching is relatively unimportant.
Assuntos
Dípteros , Himenópteros , Animais , Flores/anatomia & histologia , Néctar de Plantas , Polinização , SimbioseRESUMO
Recently, several diurnal nonhuman anthropoids have been identified displaying varying degrees of nocturnal activity, which can be influenced by activity "masking effects"-external events or conditions that suppress or trigger activity, temporarily altering normal activity patterns. Environmental masking characteristics include nocturnal temperature, rainfall, cloud cover, and moon brightness. Similarly, other ecological characteristics, including proximity to humans and predators and daytime activity, may also trigger or suppress nocturnal activity. Understanding the effects of external conditions on activity patterns is pertinent to effective species conservation. We investigated the presence of nocturnal activity and the influence of masking effects on the level of nocturnal activity displayed by wild proboscis monkeys (Nasalis larvatus) in Sabah, Malaysian Borneo. Dual-axis accelerometers were attached by collar to six male proboscis monkeys from different one-male, multi-female groups to record activity continuously (165-401 days each). We measured the monkeys' nocturnal and diurnal activity levels and investigated the effects of seven potential masking effects. Nocturnal activity was much lower than diurnal activity. Still, proboscis monkeys did display varying levels of nocturnal activity. Generalized linear mixed models identified higher nocturnal activity in the study individuals during nights with cooler temperatures, higher rainfall, and after higher diurnal activity. These three masking effects affected nocturnal activity levels during the observation period that informed our model, although they did not predict nocturnal activity outside of this period. While the generalizability of these results remains uncertain, this study highlights the utility of accelerometers in identifying activity patterns and masking effects that create variability in these patterns.
Assuntos
Presbytini , Animais , Ritmo Circadiano , Feminino , Haplorrinos , Humanos , Malásia , Masculino , Lua , TemperaturaRESUMO
Deciding whether or not to lay an egg on a given substrate is an important task undertaken by females of many arthropods. It involves perceiving the environment (e.g. quality of the substrate, temperature, and humidity), formulating a decision, and then conducting the appropriate behaviours to oviposit. This oviposition site selection (OSS) provides a useful system for studying simple decision-making. OSS in fruit flies, Drosophila melanogaster, is influenced by both genetic and environmental variation. Naturally occurring allelic variation in the foraging gene (for) is known to affect OSS. Given a choice of high- and low-nutrient oviposition substrates, groups of rovers (forR) are known to lay significantly more of their eggs on low-nutrient sites than sitters (fors) and sitter mutants (fors2). Here we ask three questions: (1) Is the role of for in OSS affected by the availability of alternate oviposition sites? (2) Is the role of for in OSS sensitive to the density of ovipositing females? and (3) Does the gustatory sensation of yeast play a role in for-mediated variation in OSS? We find a role of choice and female density in rover/sitter differences in OSS, as well as a role of for in response to glycerol, an indicator of yeast. The role of for in OSS decision-making is complex and multi-faceted and should prove fertile ground for further research into the factors affecting decision-making behaviours.
Assuntos
Proteínas Quinases Dependentes de GMP Cíclico/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/fisiologia , Oviposição/fisiologia , Animais , FemininoRESUMO
Associative learning enables animals to predict rewards or punishments by their associations with predictive stimuli, while non-associative learning occurs without reinforcement. The latter includes latent inhibition (LI), whereby animals learn to ignore an inconsequential 'familiar' stimulus. Individual honey bees display heritable differences in expression of LI. We examined the behavioral and neuronal responses between honey bee genetic lines exhibiting high and low LI. We observed, as in previous studies, that high LI lines learned a familiar odor more slowly than low LI bees. By measuring gustatory responses to sucrose, we determined that perception of sucrose reward was similar between both lines, thereby not contributing to the LI phenotype. We then used extracellular electrophysiology to determine differences in neural responses of the antennal lobe (AL) to familiar and novel odors between the lines. Low LI bees responded significantly more strongly to both familiar and novel odors than the high LI bees, but the lines showed equivalent differences in response to the novel and familiar odors. This work suggests that some effects of genotype are present in early olfactory processing, and those effects could complement how LI is manifested at later stages of processing in brains of bees in the different lines.
Assuntos
Abelhas/fisiologia , Animais , Comportamento Animal/fisiologia , Cognição/fisiologia , Condicionamento Clássico/fisiologia , Odorantes , Percepção Olfatória/fisiologia , Fenótipo , Percepção Gustatória/fisiologiaRESUMO
The interaction between insects and the flowers they pollinate has driven the evolutionary diversity of both insects and flowering plants, two groups with the most numerous species on Earth. Insects use vision and olfaction to localize host plants, but we know relatively little about how they find the tiny nectary opening in the flower, which can be well beyond their visual resolution. Especially when vision is limited, touch becomes crucial in successful insect-plant pollination interactions. Here, we studied the remarkable feeding behavior of crepuscular hawkmoths Manduca sexta, which use their long, actively controlled, proboscis to expertly explore flower-like surfaces. Using machine vision and 3D-printed artificial flower-like feeders, we revealed a novel behavior that shows moths actively probe surfaces, sweeping their proboscis from the feeder edge to its center repeatedly until they locate the nectary opening. Moreover, naive moths rapidly learn to exploit these flowers, and they adopt a tactile search strategy to more directly locate the nectary opening in as few as three to five consecutive visits. Our results highlight the proboscis as a unique active sensory structure and emphasize the central role of touch in nectar foraging insect-plant pollinator interactions.
Assuntos
Manduca , Tato , Animais , Flores , Néctar de Plantas , Plantas , PolinizaçãoRESUMO
Learning and memory are major cognitive processes strongly tied to the life histories of animals. In ants, chemotactile information generally plays a central role in social interaction, navigation and resource exploitation. However, in hunters, visual information should take special relevance during foraging, thus leading to differential use of information from different sensory modalities. Here, we aimed to test whether a hunter, the neotropical ant Ectatomma ruidum, differentially learns stimuli acquired through multiple sensory channels. We evaluated the performance of E. ruidum workers when trained using olfactory, mechanical, chemotactile and visual stimuli under a restrained protocol of appetitive learning. Conditioning of the maxilla labium extension response enabled control of the stimuli provided. Our results show that ants learn faster and remember for longer when trained using chemotactile or visual stimuli than when trained using olfactory and mechanical stimuli separately. These results agree with the life history of E. ruidum, characterized by a high relevance of chemotactile information acquired through antennation as well as the role of vision during hunting.
Assuntos
Formigas , Animais , Humanos , Aprendizagem , Memória , OlfatoRESUMO
Proboscises of many fluid-feeding insects share a common architecture: they have a partially open food canal along their length. This feature has never been discussed in relation to the feeding mechanism. We formulated and solved a fluid mechanics model of fluid uptake and estimated the time required to completely fill the food canal of the entire proboscis through the openings along its length. Butterflies and moths are taken as illustrative and representative of fluid-feeding insects. We demonstrated that the proposed mechanism of filling the proboscis with fluid through permeable lengthwise bands, in association with a thin film of saliva in the food canal, offers a competitive pathway for fluid uptake. Compared with the conventional mechanism of fluid uptake through apically restricted openings, the new mechanism provides a faster rate of fluid uptake, especially for long-tongued insects. Accordingly, long-tongued insects with permeable lengthwise bands would be able to more rapidly exploit a broader range of liquids in the form of films, pools, and discontinuous columns, thereby conserving energy and minimizing exposure to predators, particularly for hovering insects.
Assuntos
Borboletas , Animais , Trato Gastrointestinal , SalivaRESUMO
Three strains (YZ01T, YZ02 and YZ03) of Gram-stain-positive, facultatively anaerobic rods were isolated from the forestomach contents collected from a captive male proboscis monkey (Nasalis larvatus) at Yokohama Zoo in Japan. Phylogenetic analysis of the 16S rRNA gene sequences revealed that these strains belonged to the genus Lactobacillus. Based on the sequence similarity of the 16S rRNA gene, Lactobacillus delbrueckii subsp. indicus JCM 15610T was the closest phylogenetic neighbour to YZ01T. Sequence analyses of two partial concatenated housekeeping genes, the RNA polymerase alpha subunit (rpoA) and phenylalanyl-tRNA synthase alpha subunit (pheS) also indicated that the novel strains belonged to the genus Lactobacillus. The average nucleotide identity and digital DNA-DNA hybridization (dDDH) between L. delbrueckii subsp. indicus and YZ01T were 85.9 and 31.4â%, respectively. The phylogenetic tree based on the whole genomic data of strains YZ01T, YZ02 and YZ03 suggested that these three strains formed a single monophyletic cluster in the genus Lactobacillus, indicating that it belonged to a new species. The DNA G+C content of strain YZ01T was 51.6 mol%. The major fatty acids were C16â:â0 and C18â:â1 ω9c. Therefore, based on phylogenetic, phenotypic and physiological evidence, strains YZ01T, YZ02 and YZ03 represent a novel species of the genus Lactobacillus, for which the name Lactobacillus nasalidis sp. nov. is proposed with the type strain YZ01T (=JCM 33769T=DSM 110539T).