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Behaviour, vocalization and faecal metabolite concentrations of progesterone (fPM) and oestrogen were compared between receptive and non-receptive periods in female white rhinoceroses. Affiliative and olfactory-related behaviour peaked during receptive period, coinciding with hormonal oestrus and nadirs in fPM concentrations. The results reveal a sexual behavioural repertoire reflecting the hormonal state., Progesterone and oestrogen are the main gonadal steroid hormones that regulate the ovarian activity and induce the fertile oestrus period in females. The monitoring of this receptive phase is particularly decisive for captive breeding and is commonly based on the observation of female behavioural patterns that coincide with their hormonal oestrus. However, in the white rhinoceros (WR), a species that is well known for its impaired reproductive rate in captivity, the female behavioural and vocal indicators of receptivity have not been systematically investigated or linked to their hormonal states so far. In order to close this gap, we combined behavioural and acoustic recordings, conducted over an average period of 32 days, with the analysis of faecal progesterone and oestrogen metabolite concentrations (fPM and fEM) in 27 adult Southern white rhinoceros (Ceratotherium simum simum; SWR) females from 10 European zoos. For eight of the study females, we were able to detect a receptive period indicated by their acceptance of sexual behaviour from the bulls. The comparison of behaviour and vocalization between receptive and non-receptive periods in these females demonstrated that particularly presenting and marking behaviour distinctly peaked during the receptive period, indicating the significance of olfactory signalling for female reproductive behaviour. Based on the analysis of fPM profiles, we were able to identify different reproductive states (cycling, non-cycling, pregnant) in 21 of 27 study females. In contrast, fEM profiles proved to be unsuitable for the detection of ovarian activity. For the majority (five of six females for which behavioural receptivity and endocrine cyclicity were determined), a coincidence of their receptive period and the hormonal oestrus, indicated by a nadir in fPM levels, could be detected. Conclusively, this study revealed a comprehensive behavioural repertoire that reflects the hormonal oestrus in SWR females and can therefore be reliably used for non-invasive ex situ reproduction monitoring.

In insects, many critical olfactory behaviours are mediated by the large odorant receptor ( Or ) gene family, which determines the response properties of different classes of olfactory receptor neurons (ORNs). While ORN responses are generally conserved within and between Drosophila species, variant alleles of the D. melanogaster Or22 locus have previously been shown to alter the response profile of an ORN class called ab3A. These alleles show potential clinal variation, suggesting that selection is acting at this locus. Here, we investigated if the changes seen in ab3A responses lead to changes in olfactory-related behaviours. We show that variation at the Or22 locus and in the ab3A neurons are not fully compensated for by other ORNs and lead to overall changes in antennal odorant detection. We further show that this correlates with differences in odorant preference behaviour and with differences in oviposition site preference, with flies that have the chimaeric short allele strongly preferring to oviposit on banana. These findings indicate that variation at the Or22 locus leads to changes in olfactory-driven behaviours, and add support to the idea that the ab3A neurons are of especial importance to the ecology of Drosophila flies.

The chemical basis of smell remains an unsolved problem, with ongoing studies mapping perceptual descriptor data from human participants to the chemical structures using computational methods. These approaches are, however, limited by linguistic capabilities and inter-individual differences in participants. We use olfactory behaviour data from the nematodeC. elegans, which has isogenic populations in a laboratory setting, and employ machine learning approaches for a binary classification task predicting whether or not the worm will be attracted to a given monomolecular odorant. Among others, we use architectures based on Natural Language Processing methods on the SMILES representation of chemicals for molecular descriptor generation and show that machine learning algorithms trained on the descriptors give robust prediction results. We further show, by data augmentation, that increasing the number of samples increases the accuracy of the models. From this detailed analysis, we are able to achieve accuracies comparable to that in human studies and infer that there exists a non trivial relationship between the features of chemical structures and the nematode’s behaviour.

Plant viruses can manipulate their hosts to release odours that are attractive or repellent to their insect vectors. However, the volatile organic compounds (VOCs), either individually or as mixtures, which play a key role in the olfactory behaviour of insect vectors remains largely unknown. Our study focused on green rice leafhoppers (GRLHs) vectoring rice dwarf virus (RDV) revealed that RDV infection significantly induced the emission of (E)-β-caryophyllene and 2-heptanol by rice plants, which influenced the olfactory behaviour of both non-viruliferous and viruliferous GRLHs. (E)-β-caryophyllene attracted non-viruliferous GRLHs to settle on RDV-infected plants, but neither attracted nor repelled viruliferous GRLHs. In contrast, 2-heptanol repelled viruliferous GRLHs to settle on RDV-infected plants, but neither repelled nor attracted non-viruliferous GRLHs. Suppression of (E)-β-caryophyllene synthase OsCAS via CRISPR-Cas9 to generate oscas-1 plants enabled us to confirm the important role played by (E)-β-caryophyllene in modulating the virus-vector-host plant interaction. These novel results reveal the role of these virus-induced VOCs in modulating the behaviour of its GRLH insect vector and may facilitate the design of new strategies for disease control through manipulation of plant volatile emissions.

The aim of the study was to assess whether adult stallions differentiate their olfactory and marking behaviour towards the excreta of their potential male rivals and mares. Four Konik polski stallions were individually exposed simultaneously to their own and each others' faeces as well as faeces of mares in oestrus vs. dioestrus. Five series of 30min observation sessions were conducted in a round pen each on two consecutive days from March to July, totaling in 5h observation per stallion. Stallions sniffed and displayed flehmen reaction towards mares' faeces significantly longer (P

Operant conditioning is a crucial tool in neuroscience research for probing brain function. While molecular, anatomical and even physiological techniques have seen radical increases in throughput, efficiency, and reproducibility in recent years, behavioural tools have somewhat lagged behind. Here we present a fully automated, high-throughput system for self-initiated conditioning of up to 25 group-housed, radio-frequency identification (RFID) tagged mice over periods of several months and >106 trials. We validate this "AutonoMouse" system in a series of olfactory behavioural tasks and show that acquired data is comparable to previous semi-manual approaches. Furthermore, we use AutonoMouse to systematically probe the impact of graded olfactory bulb lesions on olfactory behaviour, demonstrating that while odour discrimination in general is robust to even most extensive disruptions, small olfactory bulb lesions already impair odour detection. Discrimination learning of similar mixtures as well as learning speed are in turn reliably impacted by medium lesion sizes. The modular nature and open-source design of AutonoMouse should allow for similar robust and systematic assessments across neuroscience research areas.

Operant conditioning is a crucial tool in neuroscience research for probing brain function. While molecular, anatomical and even physiological techniques have seen radical increases in throughput, efficiency, and reproducibility in recent years, behavioural tools have seen much less of an improvement. Here we present a fully automated, high-throughput system for self-initiated conditioning of up to 25 group-housed, radio-frequency identification (RFID) tagged mice over periods of several months and >10^6 trials. We validate this “AutonoMouse” system in a series of olfactory behavioural tasks and show that acquired data is comparable to previous semi-manual approaches. Furthermore, we use AutonoMouse to systematically probe the impact of graded olfactory bulb lesions on olfactory behaviour and resolve the long-standing conundrum about the apparent lack of impact of lesions on olfactory abilities. The modular nature and open-source design of AutonoMouse should allow for similar robust and systematic assessments across neuroscience research areas.

Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species due to the relatively stable conditions in deep waters for most parameters (e.g. temperature, salinity, oxygen, and pH). To explore the potential for deep-sea hermit crabs (Pagurus tanneri) to acclimate to future ocean acidification, we compared their olfactory and metabolic performance under ambient (pH ∼7.6) and expected future (pH ∼7.1) conditions. After exposure to reduced pH waters, metabolic rates of hermit crabs increased transiently and olfactory behaviour was impaired, including antennular flicking and prey detection. Crabs exposed to low pH treatments exhibited higher individual variation for both the speed of antennular flicking and speed of prey detection, than observed in the control pH treatment, suggesting that phenotypic diversity could promote adaptation to future ocean acidification.

Many animals can show either learned or innate behavioural responses to a given stimulus. However, how innate and memory circuits interact to produce an appropriate behavioural response is unknown. The Drosophila olfactory system is an excellent model to study how sensory stimuli are processed, stored and transformed into behaviour. Its numerical simplicity, powerful genetics and similarity to mammalian olfactory circuits have enabled many insights into sensory processing and memory. Two higher brain regions, the lateral horn (LH) and the mushroom body (MB) are thought to mediate innate and learned olfactory behaviour respectively, although the function of the LH has not been directly tested. Here we identify a LH cell-type (PD2a1/b1) that receives input from the MB. In contrast to the above model that LH is only necessary for innate behaviour, this cell-type is required for memory retrieval. Moreover, the activity of this cholinergic cell-type is modulated by training, indicating that memory information is passed to the innate olfactory processing centre. PD2a1/b1 dendrites likely receive input from appetitive olfactory projection neurons while their axons project to convergence zones of the MB extrinsic neurons and interdigitate with MB input and output neurons. This work demonstrates that LH neurons play a role in memory retrieval and illustrates the extensive interconnectivity of these two higher brain regions.

This chapter presents several examples of how olfactory information and farming conditions affects the behaviour of farm animals and presents opportunities to improve the welfare and production of farm animals by making use of odours and olfaction.

Current feeding behaviors contribute to the epidemic levels of obesity and diabetes observed in Europe and worldwide. Both the quantity and the quality of ingested food are incriminated. Together with other sensory modalities, olfaction is involved in the control of food intake. Olfactory cues can influence eating behaviors, yet the nutritional status and diet can also alter olfactory abilities. Patients with metabolic disorders present impaired olfactory sensitivity which could in turn worsen their eating behaviors.Here we examined the short-term impact of a Western diet enriched in fat and sugar (High Fat High Sugar, HFHS) on the anatomy and physiology of the olfactory epithelium of postnatal mice. We used a transgenic line of mice expressing GFP under the promoter of the SR1 odorant receptor in order to monitor the properties of a define population of neurons. After 8 weeks of diet, HFHS fed animals were glucose intolerant without any change in basal glycaemia and insulinemia and presented higher adiposity but no overweight compared to control mice. We measured electro-olfactogram amplitudes in response to two ligands of the SR1 olfactory receptor: amyl acetate and (R)-(+)-carvone. Detection thresholds of amyl acetate estimated from the dose-response curves were higher after 8 weeks of a HFHS diet (medians were 10-5 M for control vs 10-3 M for HFHS, p < 0.01). Reconstruction of the cilia of SR1 olfactory sensory neurons revealed shorter cilia in HFHS mice compared to control animals (4.5 ± 0.3 m vs 6.0 ± 0.3 m, p < 0.01).Our results demonstrate that diet enriched in fat and sucrose can alter the physiology of the olfactory epithelium on a short term. Anatomical changes of individual olfactory sensory neurons may participate to the reduced olfactory sensitivity. Olfactory dysfunctions appear early on after exposure to a Western diet.

The vertex-pronotal stridulatory apparatus of the female is described; the male lacks this sound producing apparatus. Females stridulated in stress, attraction, in-gallery, and rivalry contexts. In contrast to some Dendroctonus species, I. pini (females) had similar attraction and rivalry chirps, which differed from stress chirps. In-gallery chirps were longer and had a slower pulse rate than all other chirps, and were multiply interrupted. Their function was not ascertained. Attraction chirps produced by females attempting to enter a hole containing a male plus three females had more pulses/chirp and a faster pulse rate than chirps produced during attempts to enter galleries with either more or fewer females. Olfactory studies showed that the decrease in secondary attraction depended on the relation between the number of females/male in the gallery and elapsed time since the last female entered. However, these results do not indicate whether the aggregation retarding mechanism was the release of an antiattractant or merely cessation of production of the aggregative pheromone. The mean female/male sex ratio of the I. pini attracted to the test situations was 1.4/1.0, indicating a selective advantage to attracting excess males. Early colonisation observations showed that, in Oregon, nuptial chamber construction was completed within 1.4 days and the male accepted three females by 3.3 days. Zusammenfassung Das chemoakustische Verhalten von Ips pint (Say) (Col: Scolytidae) wahrend des Befalles und der Kolonisation des Wirtsbaumes Der Lauterzeugungsapparat des Weibchens von Ips pint wird beschrieben; das Mannchen besitzt keinen solchen Apparat. Die Weibchen stridulieren wahrend eines Stres-, Attraktions- und Rivalenverhaltens. Im Gegensatz zu einigen Arten der Gattung Dendroctonus produzieren die Weibchen von Ips pint Attraktion- und Rivalensignale, die akustisch ahnlich sind, sich jedoch von den Stres-Signalen unterscheiden. Die Verhaltensuntersuchungen uber die Wahrnehmung der Lockstoffe im Freiland haben gezeigt, das die Abnahme in der sekundaren Attraktion von der Zahl der Weibchen per Mannchen im Frasgange abhangig ist sowie auch von dem Zeitabschnitt, seitdem das letzte Weibchen in den Frasgang eindrang. Es ist noch nicht klar, ob diese Attraktionsabnahme durch die Abgabe eines anti-attraktiven Pheromons oder durch die Beendigung der Pheromonproduktion verursacht wird.

Resume Cette etude met en evidence l'efficacite du depot d'un marquage odorant dans la reconnaissance de l'entree du nid par les butineuses de bourdons. L'etude du comportement olfactif de ces ouvrieres a consiste a observer leur reponse en presence d'un marqueur odorant depose par d'autres ouvrieres en utilisant la methode du choix binaire. Les observations ont ete faites avec des colonies de plusieurs especes: Pyrobombus (P.) hypnorum L., Pyrobombus (M.) lapidarius L., Bombus lucorum L., Megabombus (T.) pascuorum Scop., Pyrobombus (P.) pratorum L. et Bombus terrestris L. L'experimentation a consiste egalement a faire varier qualitativement la stimulation, ce qui a permis d'etudier la capacite des ouvrieres a distinguer l'odeur de la substance deposee par les individus de leur propre colonie de celle deposee par les individus d'une autre colonie, isospecifique ou heterospecifique. Pour chaque espece etudiee, les ouvrieres retournant au nid font un choix en fonction de la nature du marquage. L'ecart entre les pourcentages de reponses est plus important dans le cas du choix entre ‘papier marque’ et ‘papier vierge’ (experience 1) que dans celui entre ‘papier marque par la colonie’ et ‘papier marque par une colonie etrangere heterospecifique’ (experience 3). Une moindre dispersion des reponses apparait dans le choix entre ‘papier marque par la colonie’ et ‘papier marque par une colonie etrangere isospecifique’ (experience 2). La discussion porte egalement sur le marquage de l'entree du nid chez des especes d'Hymenopteres solitaires terricoles, fonction attribuee a la secretion de la glande de Dufour. Le mecanisme de ce marquage chez les Apoides sociaux reste a etudier. Summary This study shows the efficiency of depositing an odoriferous marking to recognize the nest entrance by foragers of bumblebees. The study of the olfactory behaviour of these workers consisted in observing their responses to an odoriferous marker deposited by other workers, using the binary choice method. The observations were conducted with colonies of several species: Pyrobombus (P.) hypnorum L., Pyrobombus (M.) lapidarius L., Bombus lucorum L., Megabombus (Th.) pascuorum Scop., Pyrobombus (P.) pratorum L. and Bombus terrestris L. The stimulation was varied qualitatively, which made it possible to study the ability of workers to distinguish the odour of the substance deposited by individuals of their own colony from that deposited by individuals of another colony, isospecific or heterospecific. For each species studied, the returning nest workers made a choice depending on the nature of the marking. The difference between the percentages of responses was greater in the case of the choice between ‘impregnated-paper’ and ‘non-impregnated paper’ (experiment 1) than in the choice between ‘paper impregnated by their own colony’ and ‘paper impregnated by a foreign heterospecific colony’ (experiment 3). The responses were less dispersed in the choice between ‘paper impregnated by their own colony’ and ‘paper impregnated by a foreign isospecific colony’ (experiment 2). The discussion also concerns the marking of the nest entrance in solitary terricolous Hymenoptera, a function allocated to the secretion of the Dufour gland. The mechanism of this marking in social bees remains to be studied.

Nature 450, 63–70 (2007); doi:10.1038/nature06292 corrigendum Nature 451, 102 (2008); doi:10.1038/nature06540 We have discovered that Figs 1, 2, 3 and 5 and Supplementary Figs 1–5 and 7 of this Article were generated from calcium imaging data that included a number of duplicated or mislabelled moviefiles.

To develop a method for objective assessment of equine post-operative pain.Prospective nonblinded clinical study.Twelve adult horses: Group 1 (G1, n = 6), admitted for arthroscopy (under general anaesthesia, with multimodal analgesia); Group 2 (G2, n = 6), 'pain free' controls.Horses were filmed continuously (CVI, time-lapse video recorder) over 72 hours, from 24 hours pre-surgery (PS) to 48 hours post-recovery (PR) (G1), and over 24 hours (G2). Activity budgets were determined from 24 to 0 hours PS, 0-24 and 24-48 hours PR (G1) and for 24 hours (G2). Using direct observation (DO), active behaviours and postures were recorded at set time points PS and PR (G1) and at two time points (morning/evening) (G2). Heart rate (HR) and respiration rate (RR) were recorded simultaneously. Statistical analysis investigated within-group and between-group time-related changes in behaviour, HR and RR.There was no difference in HR or RR between G1 and G2 at any time point. Anaesthetic 'hangover' and hunger-related activity modulated behaviour from 0 to 6 hours PR, when abnormal postures and locomotion occurred in all G1 horses, but no G2 horses. Compared with G1 (0-24 hours PR), G2 spent more time eating (t = -3.34, p0.01), more time at the front of the stable (t = -2.42, p0.05), and less time exhibiting 'abnormal' behaviour (U = 56, p0.01). Comparing PS and PR behaviour, G1 spent less time exploring from 24 to 48 hours PR (t = 3.49, p0.05), less time in sternal recumbency (t = -3.8, p0.05) and less time moving (t = 3.19, p0.05). Horses tended (p0.07) to spend less time positioned in the front of the stable PR (less from 24 to 48 hours PR than from 0 to 24 hours PR). Comparing PR (evening) behaviour, G2 spent more time with head above withers (U = 21.5, p0.01), and ears forwards (U = 22, p0.01). G1 showed time-related changes (all p0.05) in time with lower lip tense (S = 15.8), eating (S = 17.08) and with head positioned above withers (S = 18.04). No differences in event behaviours were observed between G1 and G2. Within G1, only olfactory behaviour varied significantly with time (S = 14.52, p0.05).Changes in equine behaviour suggestive of post-operative discomfort were identified using both DO and CVI. Analysis of activity budgets may be a more sensitive method of identifying behavioural changes indicative of equine discomfort than repeated DO of specific events and postures.

It's a touching story of cohabitation and meaningful communication. Two neighbouring fruitfly neurons talk to each other not by means of synaptic junctions but by interactions through the surrounding electrical field. See Article p.66 It has been suggested that the electrical activity of one neuron can influence that of its unlinked neighbour, but this so-called ephaptic effect is widely assumed to be weak and has been relatively little studied. Here, John Carlson and colleagues demonstrate that olfactory receptor neurons (ORNs) of fruitflies communicate with one another through large ephaptic signals with significant impact on olfactory behaviour. The sustained response of one ORN is inhibited by the transient activation of its neighbour. The authors also demonstrate that a CO2-sensitive ORN in the malaria mosquito Anopheles can be inhibited by excitation of an adjacent ORN and that lateral inhibition of a CO2 neuron in Drosophila can reduce a behavioural response to CO2. As CO2 is a key cue used by mosquitoes to find human hosts, this work suggests a novel means of insect control. These findings suggest that ephaptic effects may be more widespread than previously appreciated, particularly among neurons housed in confined peripheral sensory compartments such as taste buds.

There is ample evidence that host seeking in mosquitoes is mediated by semiochemicals emanating from the host. Olfactory cues (kairomones) are detected through an intricate pathway, beginning with sensilla located on the antennae (odour) and palpi (CO2). Age and physiological state of the mosquito determine whether detection of kairomones results in a behavioural response. Only a few kairomones have been described so far. CO2 is a kairomone for most mosquito species and signifies the presence of a potential host because of its occurrence in the volatile emissions of all vertebrates. Other chemicals are likely to play a role in mosquito-host interaction as well, notably L-lactic acid, fatty acids and 1-octen-3-ol. Species-specific host preference is thought to be olfactory based and related to the presence of specialized sensilla or perception at the central olfactory pathway. Host specificity is genetically determined, as demonstrated by inherited differences within members of the Anopheles gambiae complex. In view of the available evidence, challenging research areas are: (1) the function of olfactory receptors and the level of specialization; (2) the identification of general and host-specific kairomones; (3) demonstration of behavioural responses to laboratory-identified olfactory cues in the field; (4) studying whether mosquito host-locating behaviour can be manipulated by kairomones; (5) the genetics of the regulation of olfactory behaviour; and (6) determining whether there is an olfactory basis for the evolution of mosquito-host interactions.

Constituents of Osmanthus Absolute, 4th Communication. Megastigma-5, 7 (E), 9-triene-4-one and Megastigma-5, 8 (E)-diene-4-one In continuation of our communications on constituents of Osmanthus absolute, we now report on the occurrence of the two title compounds 1 and 2a in this natural substrate (0.01-0.02% each). Their structures were confirmed by synthesis starting from β-ionone via the common intermediate 4-oxo-β-ionol (9). Some further minor components bearing corresponding structural features are tabulated in view of possible biogenetic pathways leading to 1 or 2a, respectively. In order to clarify the olfactory behaviour, we also synthesized some analogous derivatives in the irone series, these substances being not yet found in nature.

A number of genes involved in olfactory behaviour of Drosophila have been identified. The understanding of the physiology and anatomy of the first few stages of the olfactory pathway promises a reliable diagnosis of genetic lesions. The stage is thus set for studies on the molecular biology of olfaction.

This study investigated the olfactory behaviour of dogs in two situations. During spontaneous interactions with familiar children (N = 24 child-dog dyads), the olfactory behaviour of the dog appeared to differ according to the behaviours which had just been shown by the child. In an experimental situation, two dummies were dressed in underclothes which had been worn by a familiar or by an unknown child, i.e. with or without the familiar child's odour. The body areas smelt by the dogs (N = 15) differed according to whether the odour was familiar or not.

Using an apparatus of the ‘two-choice’ type under field conditions, it has been demonstrated that a wool-factor forms an important part of the mechanism whereby female Lucilia sericata may be attracted to sheep. The ‘wool-factor’ could not wholly be replaced by ammonium- or sulphydryl-type attractants. L. sericata was strongly attracted by the combination of ammonium carbonate/indole with sheep wool but less strongly attracted when ethyl mercaptan/hydrogen sulphide was used with sheep wool. L. caesar and L. illustris, on the other hand, were not markedly responsive to the ammonium-type attractants but were strongly attracted by the sulphydryl mixture used either alone or in combination with sheep wool. Temperature is an important element in the oviposition stimulus. The amount of oviposition by L. sericata was increased when substances known to induce oviposition were exposed at 30–40† C. Sheep wool kept moist and incubated at approx. 38† C. under field conditions for 3 weeks did not attract L. sericata and oviposition did not occur on such wool. This suggests that bacteria normally present on the wool fibre as distinct from the skin, do not play an important part in rendering sheep susceptible to blowfly attack.