Attractive Odor Research Articles

CRABS SMELL FEAR THROUGH ANTENNULES

Even if you're armed with a fierce pair of pincers, life can be risky. There's always going to be a larger crab that might decide to dine on you. So, crabs tend to give the odour produced by injured crabs a wide berth, treating it as a warning that a larger predator may be lurking nearby. ‘The environment is filled with threats,’ says Marc Weissburg from the Georgia Institute of Technology, USA, although it is also full of the scents of enticing tasty treats. ‘Unless you are immune to eating, then you are always going to have to confront the conflict between aversive and attractive odours’, Weissburg says. Intrigued by how crabs successfully negotiate this conflict, Weissburg and a team of undergraduate student researchers set out to discover which course blue crabs (Callinectes sapidus) steer when presented with a whiff of lunch spiced with danger (p. 4175).Collecting crabs from the ocean off Savannah, Georgia, Weissburg returned with them to the lab where he and Kimberly Berkenkamp started to test their reactions to plumes of different odours in a flow tank. Sure enough, when the animals were downstream of luscious shrimp aroma they practically galloped toward the origin. However, when the water smelled of injured crab, the animals became evasive and some even buried themselves to avoid the stench.But, how would they react when the two odours were flowing in parallel in close proximity? This time, the crabs were much more cautious. Although they continued to pursue the attractive scent, the crabs actively avoided the side of the tunnel that smelled of injured crab. Discriminating between the plumes and following the attractive odour to its source, the crabs were able to successfully home in on the food despite the close proximity of the warning signal.However, when the duo disrupted the flow by introducing a cylinder into the water, to generate turbulence and mix the plumes, Weissburg says, ‘The animals were no longer willing to track to the attractive source and they reacted as if there was only an aversive source’. Thoroughly mixing the two odours had altered the crab's perception of the tasty prawn aroma sufficiently for it to no longer appear attractive. Weissburg decided to find out which of their many olfactory organs the crabs use to distinguish between the attractive and aversive odours.‘In blue crabs, the control over orientation toward an attractive substance is split between the antennules, which are the small structures between the eyes on the head, and chemosensors on the tips of the walking legs’, explains Weissburg. So, together with Lauren Atkins and Danielle Mankin, he tested the animals' reactions to the merged plume when one or other of the ‘nostrils’ were effectively plugged.Desensitizing the scent receptors on a crab's legs by immersing them in fresh water, Weissburg then released the animal into the blended plume: the animal tried to take cover. However, after gently removing the scent receptors from another crabs' antennules and positioning it in the plume mixture, the animal bounded toward the source of the attractive aroma of food as if it was uncontaminated. The crab was no longer repelled by the aversive odour. ‘We had knocked out the input [from the antennules] that suppresses navigation. The behaviour of the animals to track the attractive cue in the presence of the aversive cue was rescued’, explains Weissburg.

Dine or dash? Turbulence inhibits blue crab navigation in attractive–aversive odor plumes by altering signal structure encoded by the olfactory pathway

Blue crabs can distinguish and navigate to attractive (food) odors even when aversive odors (injured crab metabolites) are released nearby. Blue crabs in these conditions detect the aversive odor and avoid it, but find the attractive source with nearly the same success rate as when the attractive source is presented alone. Spatially and temporally distinct odor filaments appear to signal to foragers that the two odor sources are not co-located, and hence navigating to the attractive odor entails an acceptable risk of predation. However, environmentally produced turbulence suppresses tracking by homogenizing the two odors; blue crabs fail to track to the attractive source when the aversive source is present, even though turbulence does not substantially inhibit tracking to the attractive source alone. Removal of sensory input from aesthetascs on the antennules, but not chemosensors on the legs, rescues navigation to attractive-aversive dual plumes in turbulent conditions. These results suggest that mixing in the natural environment may amplify the effects of predators by suppressing tracking to food odors when aversive cues are present, and that the olfactory pathway mediates the response.

A Model of the Intracellular Response of an Olfactory Neuron in Caenorhabditis elegans to Odor Stimulation

We developed a mathematical model of a hypothetical neuronal signal transduction pathway to better understand olfactory perception in Caenorhabditis elegans. This worm has only three pairs of olfactory receptor neurons. Intracellular Ca2+ decreases in one pair of olfactory neurons in C. elegans, the AWC neurons, following application of an attractive odor and there is a transient increase in intracellular Ca2+ following removal of odor. The magnitude of this increase is positively correlated with the duration of odor stimulation. Additionally, this Ca2+ transient is induced by a cGMP second messenger system. We identified likely candidates for the signal transduction molecules functioning in this system based on available gene expression and physiological data from AWCs. Our model incorporated a G-protein-coupled odor receptor, a G-protein, a guanylate cyclase as the G-protein effector, and a single phosphodiesterase. Additionally, a cyclic-nucleotide-gated ion channel and a voltage-gated ion channel that mediated calcium influx were incorporated into the model. We posited that, upon odor stimulation, guanylate cyclase was suppressed by the G-protein and that, upon cessation of the stimulus, the G-protein–induced suppression ceased and cGMP synthesis was restored. A key element of our model was a Ca2+-dependent negative feedback loop that ensured that the calcium increases were transient. Two guanylate cyclase-activating proteins acted on the effector guanylate cyclase to negatively regulate cGMP signaling and the resulting calcium influx. Our model was able to closely replicate in silico three important features of the calcium dynamics of AWCs. Specifically, in our simulations, [Ca2+] increased rapidly and reached its peak within 10 s after the odor stimulus was removed, peak [Ca2+] increased with longer odor exposure, and [Ca2+] decreased during a second stimulus that closely followed an initial stimulus. However, application of random background signal (‘noise’) showed that certain components of the pathway were particularly sensitive to this noise.

Behavioral interactions and rhythms of activity of Glossina palpalis gambiensis and G. tachinoides (Diptera: Glossinidae) in a forest gallery in Burkina Faso

Glossina palpalis gambiensis et G. tachinoides sont des vecteurs majeurs des trypanosomoses humaines et animales en Afrique de l’Ouest. Sur une partie de leur aire de répartition, elles sont présentes en sympatrie, mais très peu d’informations sont disponibles sur leurs interactions. Nous avons capturé ces deux espèces en utilisant un système attractif composé d’écrans de tissu noir/bleu/ noir muni de film adhésif, afin de retenir toutes les glossines posées et de pouvoir mesurer la hauteur à laquelle elles se sont posées, ainsi que leur rythme d’activité en fonction de l’heure de la journée. L’étude a eu lieu dans deux zones du sud du Burkina Faso : Kartasso en amont du fleuve Mouhoun, où seule G. p. gambiensis est présente, et Folonzo sur le fleuve Comoé, où les deux espèces cohabitent. Les résultats, sur 3 800 glossines capturées, montrent une forte prédominance des captures de G. tachinoides par rapport à G. p. gambiensis à Folonzo (84 % contre 16 % des captures respectivement). À Kartasso, où elle est seule, G. p. gambiensis est capturée en moyenne à 46 cm du sol. À Folonzo, G. p. gambiensis est en moyenne attrapée à une hauteur de 65 cm, et G. tachinoides à 55 cm, ces différences de hauteurs étant significatives. Les femelles sont capturées en général plus haut que les mâles. Les deux espèces montrent un rythme d’activité similaire en fonction de l’heure de capture, mais seule G. p. gambiensis réduit sa hauteur de vol aux heures les plus chaudes. Plusieurs hypothèses, non exclusives, sont évoquées pour expliquer ces hauteurs de capture différentes : la nature de la galerie forestière, un comportement d’approche qui différerait entre espèces, mais aussi la possibilité de phénomènes de compétition interspécifique en relation avec l’utilisation de ressources énergétiques limitées (métabolisme lié à la proline). Sont également discutées les conséquences possibles de ces différences de comportement sur les méthodes de lutte, par exemple lors de l’utilisation d’attractifs olfactifs qui pourraient avoir des efficacités distinctes en fonction de la hauteur de vol.

Flies dynamically anti-track, rather than ballistically escape, aversive odor during flight

Tracking distant odor sources is crucial to foraging, courtship and reproductive success for many animals including fish, flies and birds. Upon encountering a chemical plume in flight, Drosophila melanogaster integrates the spatial intensity gradient and temporal fluctuations over the two antennae, while simultaneously reducing the amplitude and frequency of rapid steering maneuvers, stabilizing the flight vector. There are infinite escape vectors away from a noxious source, in contrast to a single best tracking vector towards an attractive source. Attractive and aversive odors are segregated into parallel neuronal pathways in flies; therefore, the behavioral algorithms for avoidance may be categorically different from tracking. Do flies plot random ballistic or otherwise variable escape vectors? Or do they instead make use of temporally dynamic mechanisms for continuously and directly avoiding noxious odors in a manner similar to tracking appetitive ones? We examine this question using a magnetic tether flight simulator that permits free yaw movements, such that flies can actively orient within spatially defined odor plumes. We show that in-flight aversive flight behavior shares all of the key features of attraction such that flies continuously 'anti-track' the noxious source.

Altered olfactory function in the MRL model of CNS lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that damages several bodily systems, including the CNS. Brain atrophy and diverse neuropsychiatric manifestations are common and serious complications of SLE. Recently, it has been reported that many patients with CNS involvement also present with olfactory deficits of unknown etiology. Similar to CNS SLE, spontaneous development of lupus-like disease in MRL/lpr mice is accompanied by neurodegeneration in periventricular regions and a constellation of behavioral deficits dependent on olfaction. To test the possibility that olfactory dysfunction also occurs in autoimmune mice, we presently examine odor-guided behaviors using a battery of paradigms. Indeed, lupus-prone males spent less time exploring unfamiliar conspecifics and demonstrated age-dependant performance deficits when exposed to low concentrations of attractant and repellant odors. The emergence of olfactory changes was associated with a skewed distribution of DCX+ cells in the proximal portion of the rostral migratory stream (RMS). The present results are consistent with the hypothesis that the onset of a SLE-like condition affects periventricular regions, including the RMS, as evidenced by disrupted migration of neuronal precursor cells toward the olfactory bulb. If so, ensuing hyposmia and/or olfactory memory deficit may contribute to altered performance in other behavioral tasks and reflect a prodrome of brain damage induced by chronic autoimmune disease.

A high-throughput behavioral paradigm for Drosophila olfaction - The Flywalk

How can odor-guided behavior of numerous individual Drosophila be assessed automatically with high temporal resolution? For this purpose we introduce the automatic integrated tracking and odor-delivery system Flywalk. In fifteen aligned small wind tunnels individual flies are exposed to repeated odor pulses, well defined in concentration and timing. The flies' positions are visually tracked, which allows quantification of the odor-evoked walking behavior with high temporal resolution of up to 100 ms. As a demonstration of Flywalk we show that the flies' behavior is odorant-specific; attractive odors elicit directed upwind movements, while repellent odors evoke decreased activity, followed by downwind movements. These changes in behavior differ between sexes. Furthermore our findings show that flies can evaluate the sex of a conspecific and males can determine a female's mating status based on olfactory cues. Consequently, Flywalk allows automatic screening of individual flies for their olfactory preference and sensitivity.

Characterization of Resistance, Evaluation of the Attractiveness of Plant Odors, and Effect of Leaf Color on Different Onion Cultivars to Onion Thrips (Thysanoptera: Thripidae)

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a worldwide pest of onion, Allium cepa L. In field studies on onion resistance conducted in 2007 and 2008 using 49 cultivars, 11 showed low leaf damage by T. tabaci. In laboratory studies, the 11 cultivars, along with two susceptible checks and four additional cultivars, were evaluated to characterize resistance to T. tabaci and to determine if color and/or light reflectance were associated with resistance to T tabaci. No-choice tests were performed with adults and the numbers of eggs and larvae were counted on each cultivar after three and 10 d, respectively. In choice tests in which all cultivars were planted together in a circle in a single pot, 100 adults were released and the number of adults on each plant was evaluated 24 h later. The behavioral response of walking T. tabaci adults to plant odors was studied in a glass Y-tube olfactometer. The reflectance spectrum of leaves was measured using a UV-VIS spectrophotometer. Results indicate that resistant cultivars showed an intermediate-high antibiotic effect to T. tabaci and all of them showed a very strong antixenotic effect. There were no significant preferences in the response of walking T. tabaci adults to plant odors. The two susceptible cultivars had the highest values of leaf reflectance for the first (275-375 nm) and second (310-410 nm) theoretical photopigment-system of T. tabaci, and these values were significantly different from most resistant cultivars. These results suggest a strong response of T. tabaci to onion cultivars with higher reflectance in the ultraviolet range (270-400 nm). Overall, these results appear promising in helping to identify categories of resistance to T. tabaci in onions that can be used in breeding programs.

Spatial Representation of Odorant Valence in an Insect Brain

Brains have to decide whether and how to respond to detected stimuli based on complex sensory input. The vinegar fly Drosophila melanogaster evaluates food sources based on olfactory cues. Here, we performed a behavioral screen using the vinegar fly and established the innate valence of 110 odorants. Our analysis of neuronal activation patterns evoked by attractive and aversive odorants suggests that even though the identity of odorants is coded by the set of activated receptors, the main representation of odorant valence is formed at the output level of the antennal lobe. The topographic clustering within the antennal lobe of valence-specific output neurons resembles a corresponding domain in the olfactory bulb of mice. The basal anatomical structure of the olfactory circuit between insects and vertebrates is known to be similar; our study suggests that the representation of odorant valence is as well.

Do Trained Dogs Discriminate Individual Body Odors of Women Better than Those of Men?*

Scent identification lineups using dogs are a potentially valuable forensic tool, but have been dismissed by some critics because of cases where a false identification was shown to have occurred. It is not known, however, why dogs appear to make more false indications to the odors of some persons than of others. In this study, human genders were compared as to the degree their individual odors are distinguishable or "attractive" to dogs. Six dogs were trained to smell an individual's hand odor sample and then find the matching hand odor sample in a lineup of five odors. Using one-gender lineups and two-gender lineups with different gender ratios, it was found that dogs trained for the study identified individual women's hand odors more accurately than those of men. It is hypothesized that this is either because of differences in chemical compounds making discrimination of women's odors easier, or because of greater "odor attractiveness" of women's scents to dogs.

Spatial representation of odorant valence in an insect brain

Event Abstract Back to Event Spatial representation of odorant valence in an insect brain Markus Knaden1*, Antonia Strutz1, Jawaid Ahsan1, Silke Sachse1, Kathrin Steck1 and Bill S. Hansson1 1 Max Planck Society, Evolutionary Neuroethology, Germany Brains have to decide whether and how to respond to detected stimuli based on complex sensory input. The vinegar fly Drosophila melanogaster evaluates food sources based on olfactory cues. Here we performed a behavioral screen using the vinegar fly and established the innate valence of 110 odorants. All odors were tested in ten replicates of a two choice assay for their attractiveness to a group of each time 50 flies (Knaden et al. 2012). Very attractive and repellent odorants were furthermore tested in more detail in the new paradigm Flywalk (Steck et al. 2012): In fifteen aligned small wind tunnels individual flies were exposed to repeated odorant pulses (Fig.1, Movie 1), well defined in concentration and timing. The flies’ positions were visually tracked, which allowed quantification of the odorant-evoked walking behavior with high temporal resolution of up to 100 ms. We found that the flies’ behavior was odorant-specific; attractive odorants elicited directed upwind movements, while repellent odorants evoked decreased activity, followed by downwind movements. These changes in behavior differed between sexes. By performing calcium imaging experiments we then tested the neuronal activation patterns evoked by the six most attractive and the six most repellent odorants within the antennal lobe (Knaden et al. 2012). Our analysis suggests that even though the identity of odorants is coded by the set of activated receptors, the main representation of odorant valence is formed at the output level of the antennal lobe. The topographic clustering within the antennal lobe of valence-specific output neurons resembles a corresponding domain in the olfactory bulb of mice. The basal anatomical structure of the olfactory circuit between insects and vertebrates is known to be similar; our study suggests that the representation of odorant valence is as well. Figure 1 References Knaden M, Strutz A, Ahsan J, Sachse S, Hansson BS (2012). Spatial representation of odorant valence in an insect brain. Cell Reports 1, 392–399. Steck K,Veit D, Grandy R, Bermudez i Badia S, Mathews Z, Verschure P, Hansson BS, Knaden M (2012). A high-throughput behavioral paradigm for Drosophila olfaction - The Flywalk. Nature Scientific Reports 2 : 361. Keywords: antennal lobe, Behavior, Drosophila, High throughput screening, Olfaction, Olfactory coding Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Sensory: Olfaction and Taste Citation: Knaden M, Strutz A, Ahsan J, Sachse S, Steck K and Hansson BS (2012). Spatial representation of odorant valence in an insect brain. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00252 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Dr. Markus Knaden, Max Planck Society, Evolutionary Neuroethology, Jena, 07745, Germany, mknaden@ice.mpg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Markus Knaden Antonia Strutz Jawaid Ahsan Silke Sachse Kathrin Steck Bill S Hansson Google Markus Knaden Antonia Strutz Jawaid Ahsan Silke Sachse Kathrin Steck Bill S Hansson Google Scholar Markus Knaden Antonia Strutz Jawaid Ahsan Silke Sachse Kathrin Steck Bill S Hansson PubMed Markus Knaden Antonia Strutz Jawaid Ahsan Silke Sachse Kathrin Steck Bill S Hansson Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Dissecting a central flip-flop circuit that integrates contradictory sensory cues in C. elegans feeding regulation

Feeding behaviour is modulated by both environmental cues and internal physiological states. Appetite is commonly boosted by the pleasant smell (or appearance) of food and destroyed by a bad taste. In reality, animals sense multiple environmental cues at the same time and it is not clear how these sensory inputs are integrated and a decision is made to regulate feeding behaviour accordingly. Here we show that feeding behaviour in Caenorhabditis elegans can be either facilitated by attractive odours or suppressed by repellents. By identifying mutants that are defective for sensory-mediated feeding regulation, we dissected a central flip-flop circuit that integrates two contradictory sensory inputs and generates bistable hormone output to regulate feeding behaviour. As feeding regulation is fundamental to animal survival, we speculate that the basic organizational logic identified here in C. elegans is likely convergent throughout different phyla.

Influence of Iron Deficiency on Olfactory Behavior in Weanling Rats

Chronically high occupational exposure to airborne metals like iron can impair olfactory function, but little is known about how low iron status modifies olfactory behavior. To investigate the influence of body iron status, weanling rats were fed a diet with low iron content (4 - 7 ppm) to induce iron deficiency anemia and olfactory behavior was compared to control rats fed an isocaloric diet sufficient in iron (210 - 220 ppm). Iron-deficient rats had prolonged exploratory time for attractive odorants in behavioral olfactory habituation/dis-habituation tests, olfactory preference tests and olfactory sensitivity tests compared with control rats. No significant differences were observed for aversive odorants between the two groups. These findings suggest that iron-dependent functions may be involved in controlling and processing of olfactory signal transduction via self and lateral inhibition such that odorant signal remains stronger for longer times prolonging exploratory activity on attractive odorants in the behavioral tests. These findings establish that iron deficiency can modify olfactory behavior.

Drosophila track CO2 in flight

Event Abstract Back to Event Drosophila track CO2 in flight Sara Wasserman1, Daniel Malkin1 and Mark A. Frye1* 1 UCLA/Howard Hughes Medical Institute, Department of Integrative Biology and Physiology, United States Natural environments contain both attractive and aversive signals and organisms must encode both the direction and valence of these stimuli to control appropriate behavioral responses. Drosophila melanogaster tracks the spatial gradient of both attractive and aversive odors in flight. The need for adult fruit flies to locate and track both attractive and aversive olfactory cues is crucial for foraging, oviposition, and courtship. However, assigning a positive or negative valance to an odor can be dependent upon the behavioral or physiological state of the animal. Carbon dioxide (CO2) is released from fly food sources and oviposition sites. As such, CO2 emanating from a host has been shown to elicit attractive flight responses from mosquitos, but, paradoxically has been shown to be innately aversive to walking fruit flies. Here, we explore D. melanogaster in-flight olfactory behavior to CO2. We find that the valance assigned to CO2, a prevalent environmental stimulus is flexible and is determined by the behavioral state (walking vs. flying) of the fruit fly. Whereas we replicate avoidance responses in standard walking assays, interestingly, CO2 elicits active plume tracking during tethered flight. As previously reported, tethered fruit flies actively track an apple cider vinegar (ACV) plume. On average one animal will spend 7.4±0.7sec in an ACV plume over a 25sec trial. CO2 plume tracking is less robust when compared to ACV, with an average of 3.6±0.6sec spent in the plume. Overall, flies spend a significantly greater amount of time in an ACV or CO2 plume as compared to an air plume (1.8±0.3sec). This first look at in-flight responses to CO2 suggests that the fly assigns valence to environmental stimuli in a behavioral state-dependent manner. Keywords: Behavior, Carbon Dioxide, Drosophila melanogaster, flight, Odor Tracking Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster Presentation (see alternatives below as well) Topic: Sensorimotor Integration Citation: Wasserman S, Malkin D and Frye MA (2012). Drosophila track CO2 in flight. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00133 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Prof. Mark A Frye, UCLA/Howard Hughes Medical Institute, Department of Integrative Biology and Physiology, Los Angeles, CA, 90095-7239, United States, frye@ucla.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sara Wasserman Daniel Malkin Mark A Frye Google Sara Wasserman Daniel Malkin Mark A Frye Google Scholar Sara Wasserman Daniel Malkin Mark A Frye PubMed Sara Wasserman Daniel Malkin Mark A Frye Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Load-associated Modulation of the Overlap between the Fore and Hind Wings in the Moth Manduca sexta.

Event Abstract Back to Event Load-associated Modulation of the Overlap between the Fore and Hind Wings in the Moth Manduca sexta. Anna Malec1 and Mark A. Willis1* 1 Case Western Reserve University, Biology, United States Males and females of the North American hawk moth Manduca sexta differ morphologically in a number of ways. One of the most apparent is the significantly greater weight of the females resulting from the eggs filling their abdomens from the moment they emerge from the pupae. On average, the females are also longer from head-to-tail and have a broader wingspan than males. The females’ wingspan may not compensate completely for their increased weight as they still have a wing loading about 12% greater than that of males. Since M. sexta are four-winged fliers, it is possible that they can adjust the overlap between their fore and hind wings to transiently either increase their functional wing area (i.e., decrease their wing loading) or increase the flexibility of the pair of wings on each side of the thorax. Recent studies have shown that flight force production varies with the flexural stiffness of the wings in M. sexta. We hypothesized that females may alter the overlap between their fore and hind wings to compensate for their innately greater loading. Since the wings on each side of the body of M. sexta move as a synchronized unit, it is possible that altering the amount they overlap could alter their overall flexural stiffness, and forces produced. To test this idea, we recorded male and female M. sexta with high-speed video cameras as they tracked a plume of attractive odorant (i.e., female pheromone or fresh tobacco leaves) upwind in two different wind speeds. We observed a small, but statistically significant difference in the overlap of fore and hind wings between the males and females. Females overlapped their wings significantly less than males in both wind speeds. However, regression analyses of our results show that changes in wing overlap are most strongly associated with the weight of the moths. Experiments are ongoing to determine if the observed changes in overlap are actively controlled by the moths or a passive property of the mechanics of the flight system. Acknowledgements We would like to thank Ms. Jennifer Avondet for her assistance in managing the insect colony and for training and help associated with all aspects of this project. A.M. M. was supported by the Summer Program in Undergraduate Research, funded by the Howard Hughes Medical Institute. M.A.W. was supported by an Air Force Office of Scientific Research grant FA9550-07-0149. We would also like to thank Dr. Ken Moriuchi for his indispensable assistance with statistics. Keywords: flight, insect, Locomotion, Manduca sexta, moth, Wing Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Motor Systems Citation: Malec A and Willis MA (2012). Load-associated Modulation of the Overlap between the Fore and Hind Wings in the Moth Manduca sexta.. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00298 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Dr. Mark A Willis, Case Western Reserve University, Biology, Cleveland, Ohio, 44106-7080, United States, maw27@case.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Anna Malec Mark A Willis Google Anna Malec Mark A Willis Google Scholar Anna Malec Mark A Willis PubMed Anna Malec Mark A Willis Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Associative learning in the dengue vector mosquito,Aedes aegypti: avoidance of a previously attractive odor or surface color that is paired with an aversive stimulus

Associative learning has been shown in a variety of insects, including the mosquitoes Culex quinquefasciatus and Anopheles gambiae. This study demonstrates associative learning for the first time in Aedes aegypti, an important vector of dengue, yellow fever and chikungunya viruses. This species prefers to rest on dark surfaces and is attracted to the odor of 1-octen-3-ol. After training in which a dark surface alone or a dark surface with odor was paired with electric shock, mosquitoes avoided the previously attractive area. The association was stronger when odor was included in training, was retained for at least 60 min but not for 24 h, and was equal for males and females. These results demonstrate the utility of a bulk-training paradigm for mosquitoes similar to that used with Drosophila melanogaster.

Foraging Behavior of the Blue Morpho and Other Tropical Butterflies: The Chemical and Electrophysiological Basis of Olfactory Preferences and the Role of Color

Inside a live butterfly exhibit, we conducted bioassays to determine whether the presence of color would facilitate the location of attractants by the butterflies. It was found that color facilitated odor attraction in some species that feed on flowers (Parthenos silvia, Heraclides thoas, Dryas julia, andIdea leuconoe), but not in the exclusively fruit-feeding species, such asMorpho helenor, hence demonstrating that species with different natural diets use different foraging cues. Green, ripe, and fermented bananas were evaluated for their attractiveness to butterflies together with honey and mangoes. The fermented bananas were determined to be the most attractive bait, and the electrophysiological responses to their volatiles were studied inMorpho helenorandCaligo telamonius. During GC-EAD evaluation, fifteen different aliphatic esters, such as isobutyl isobutyrate, butyl acetate, ethyl butanoate, and butyl butanoate (both fermentation products and fruit semiochemicals) were shown to be detected by the butterflies’ sensory apparatus located in the forelegs, midlegs, proboscis, labial palpi, and antennae. Legs, proboscis, and antennae ofMorpho helenorandCaligo telamoniusshowed similar sensitivity, reacting to 11 chemicals, while labial palpi had a lower signal-to-noise ratio and responded to seven chemicals, only three of which produced responses in other organs.

Antigen-induced changes in odor attractiveness and reproductive output in male mice

Modulation of social signals by antigen-induced immunoenhancement is a significant component of behavioral and reproductive adaptations of a host population to parasitic pressure. To investigate this concept, we studied odor attractiveness and reproductive output of ICR male mice treated with keyhole limpet hemocyanin (KLH) as an antigenic stimulus. We collected urine samples for olfactory preference tests (control vs. KLH administration) on different days following treatment. We found that the differences in odor attractiveness between control and immunized males, which were observed on the 3rd day, disappeared soon afterwards. Odor attractiveness of male mice positively correlated with their immunoresponsiveness, which was assessed by the sum of anti-KLH IgG1 and anti-KLH IgG2a titers. According to the hypothesis of terminal investment, antigen-treated males had higher reproductive output in comparison with control males and produced more progeny as a result.

Body odor attractiveness as a cue of impending ovulation in women: Evidence from a study using hormone-confirmed ovulation

Scent communication plays a central role in the mating behavior of many nonhuman mammals but has often been overlooked in the study of human mating. However, a growing body of evidence suggests that men may perceive women's high-fertility body scents (collected near ovulation) as more attractive than their low-fertility body scents. The present study provides a methodologically rigorous replication of this finding, while also examining several novel questions. Women collected samples of their natural body scent twice — once on a low-fertility day and once on a high-fertility day of the ovulatory cycle. Tests of luteinizing hormone confirmed that women experienced ovulation within two days of their high-fertility session. Men smelled each woman's high- and low-fertility scent samples and completed discrimination and preference tasks. At above-chance levels, men accurately discriminated between women's high- and low-fertility scent samples (61%) and chose women's high-fertility scent samples as more attractive than their low-fertility scent samples (56%). Men also rated each scent sample on sexiness, pleasantness, and intensity, and estimated the physical attractiveness of the woman who had provided the sample. Multilevel modeling revealed that, when high- and low-fertility scent samples were easier to discriminate from each other, high-fertility scent samples received even more favorable ratings compared with low-fertility scent samples. This study builds on a growing body of evidence indicating that men are attracted to cues of impending ovulation in women and raises the intriguing question of whether women's cycling hormones influence men's attraction and sexual approach behavior.

Fatal Attraction Phenomenon in Humans – Cat Odour Attractiveness Increased for Toxoplasma-Infected Men While Decreased for Infected Women

BackgroundLatent toxoplasmosis, a lifelong infection with the protozoan Toxoplasma gondii, has cumulative effects on the behaviour of hosts, including humans. The most impressive effect of toxoplasmosis is the “fatal attraction phenomenon,” the conversion of innate fear of cat odour into attraction to cat odour in infected rodents. While most behavioural effects of toxoplasmosis were confirmed also in humans, neither the fatal attraction phenomenon nor any toxoplasmosis-associated changes in olfactory functions have been searched for in them.Principal FindingsThirty-four Toxoplasma-infected and 134 noninfected students rated the odour of urine samples from cat, horse, tiger, brown hyena and dog for intensity and pleasantness. The raters were blind to their infection status and identity of the samples. No signs of changed sensitivity of olfaction were observed. However, we found a strong, gender dependent effect of toxoplasmosis on the pleasantness attributed to cat urine odour (p = 0.0025). Infected men rated this odour as more pleasant than did the noninfected men, while infected women rated the same odour as less pleasant than did noninfected women. Toxoplasmosis did not affect how subjects rated the pleasantness of any other animal species' urine odour; however, a non-significant trend in the same directions was observed for hyena urine.ConclusionsThe absence of the effects of toxoplasmosis on the odour pleasantness score attributed to large cats would suggest that the amino acid felinine could be responsible for the fatal attraction phenomenon. Our results also raise the possibility that the odour-specific threshold deficits observed in schizophrenia patients could be caused by increased prevalence of Toxoplasma-infected subjects in this population rather than by schizophrenia itself. The trend observed with the hyena urine sample suggests that this carnivore, and other representatives of the Feliformia suborder, should be studied for their possible role as definitive hosts in the life cycle of Toxoplasma.