scholarly journals Moths sense, but do not learn flower odors with their proboscis during flower investigation

2021 ◽  
Author(s):  
Elisabeth Adam ◽  
Bill S. Hansson ◽  
Markus Knaden
Keyword(s):  
Manduca Sexta ◽  
Cross Talk ◽  
Olfactory Learning ◽  
Foraging Efficiency ◽  
Nicotiana Attenuata ◽  
Olfactory Sensilla ◽  
Artificial Flower ◽  
Odor Learning ◽  
Insect Pollinators ◽  
Flower Handling

Insect pollinators, like the tobacco hawkmoth Manduca sexta, are known for locating flowers and learning floral odors by using their antennae. A recent study revealed, however, that the tobacco hawkmoth additionally possesses olfactory sensilla at the tip of its proboscis. Here, we ask whether this second “nose” of the hawkmoth is similarly involved in odor learning as are the antennae. We first show that Manduca foraging efficiency at Nicotiana attenuata flowers increases with experience. This raises the question whether olfactory learning with the proboscis is playing a role during flower handling. By rewarding the moths at an artificial flower, we show that – while moths learn an odor easily when they perceive it with their antennae – experiencing the odor just with the proboscis is not sufficient for odor learning. Furthermore, experiencing the odor with the antennae during training does not affect the behavior of the moths when they later can detect the learned odor with the proboscis only. Therefore, there seems to be no cross-talk between antennae and proboscis and information learnt by the antennae cannot be retrieved by the proboscis.

scholarly journals Hawkmoths evaluate scenting flowers with the tip of their proboscis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Alexander Haverkamp ◽  
Felipe Yon ◽  
Ian W Keesey ◽  
Christine Mißbach ◽  
Christopher Koenig ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Manduca Sexta ◽  
Ecosystem Service ◽  
Floral Scent ◽  
Nicotiana Attenuata ◽  
Floral Volatiles ◽  
Pollen Transfer ◽  
Olfactory Neurons ◽  
Molecular Analyses ◽  
Choice Tests

Pollination by insects is essential to many ecosystems. Previously, we have shown that floral scent is important to mediate pollen transfer between plants (<xref ref-type="bibr" rid="bib16">Kessler et al., 2015</xref>). Yet, the mechanisms by which pollinators evaluate volatiles of single flowers remained unclear. Here, Nicotiana attenuata plants, in which floral volatiles have been genetically silenced and its hawkmoth pollinator, Manduca sexta, were used in semi-natural tent and wind-tunnel assays to explore the function of floral scent. We found that floral scent functions to increase the fitness of individual flowers not only by increasing detectability but also by enhancing the pollinator's foraging efforts. Combining proboscis choice tests with neurophysiological, anatomical and molecular analyses we show that this effect is governed by newly discovered olfactory neurons on the tip of the moth's proboscis. With the tip of their tongue, pollinators assess the advertisement of individual flowers, an ability essential for maintaining this important ecosystem service.

scholarly journals Spatial odor discrimination in hawkmoth, Manduca sexta (L.)

2020 ◽  
Author(s):  
P. Kalyanasundaram ◽  
M. A. Willis
Keyword(s):  
Spatial Distribution ◽  
Manduca Sexta ◽  
Flight Control ◽  
Spatial Information ◽  
Egg Laying ◽  
Proboscis Extension Reflex ◽  
Flying Insects ◽  
Odor Learning ◽  
Odor Plumes ◽  
Proboscis Extension

AbstractFlying insects track turbulent odor plumes to find mates, food and egg-laying sites. To maintain contact with the plume, insects are thought to adapt their flight control according to the distribution of odor in the plume using the timing of odor onsets and intervals between odor encounters. Although timing cues are important, few studies have addressed whether insects are capable of deriving spatial information about odor distribution from bilateral comparisons between their antennae in flight. The proboscis extension reflex (PER) associative learning protocol, originally developed to study odor learning in honeybees, was modified to show hawkmoths, Manduca sexta, can discriminate between odor stimuli arriving on either antenna. We show moths discriminated the odor arrival side with an accuracy of >70%. The information about spatial distribution of odor stimuli is thus available to moths searching for odor sources, opening the possibility that they use both spatial and temporal odor information.

scholarly journals Shifting Nicotiana attenuata 's diurnal rhythm does not alter its resistance to the specialist herbivore Manduca sexta

2016 ◽  
Vol 58 (7) ◽  
pp. 656-668 ◽  
Author(s):  
Jasmin Herden ◽  
Stefan Meldau ◽  
Sang-Gyu Kim ◽  
Grit Kunert ◽  
Youngsung Joo ◽  
...  
Keyword(s):  
Manduca Sexta ◽  
Diurnal Rhythm ◽  
Nicotiana Attenuata ◽  
Specialist Herbivore

scholarly journals Variation in Manduca sexta Pollination-Related Floral Traits and Reproduction in a Wild Tobacco Plant

2021 ◽  
Vol 9 ◽  
Author(s):  
Julia Bing ◽  
Xiang Li ◽  
Alexander Haverkamp ◽  
Ian T. Baldwin ◽  
Bill S. Hansson ◽  
...  
Keyword(s):  
Manduca Sexta ◽  
Seed Set ◽  
Tobacco Plant ◽  
The Other ◽  
Floral Traits ◽  
Nicotiana Attenuata ◽  
Pollination Syndromes ◽  
Pollination Services ◽  
Flower Opening ◽  
Local Adaptations

Most flowering plants depend on animal pollination for successful sexual reproduction. Floral signals such as color, shape, and odor are crucial in establishing this (often mutualistic) interaction. Plant and pollinator phenotypes can vary temporally but also spatially, thus creating mosaic-like patterns of local adaptations. Here, we investigated natural variation in floral morphology, flower volatile emission, and phenology in four accessions of a self-compatible wild tobacco, Nicotiana attenuata, to assess how these traits match the sensory perception of a known pollinator, the hawkmoth Manduca sexta. These accessions differ in floral traits and also in their habitat altitudes. Based on habitat temperatures, the accession occurring at the highest altitude (California) is less likely to be visited by M. sexta, while the others (Arizona, Utah 1, and Utah 2) are known to receive M. sexta pollinations. The accessions varied significantly in flower morphologies, volatile emissions, flower opening, and phenology, traits likely important for M. sexta perception and floral handling. In wind tunnel assays, we assessed the seed set of emasculated flowers after M. sexta visitation and of natural selfed and hand-pollinated selfed flowers. After moth visitations, plants of two accessions (Arizona and Utah 2) produced more capsules than the other two, consistent with predictions that accessions co-occurring with M. sexta would benefit more from the pollination services of this moth. We quantified flower and capsule production in four accessions in a glasshouse assay without pollinators to assess the potential for self-pollination. The two Utah accessions set significantly more seeds after pollen supplementation compared with those of autonomous selfing flowers, suggesting a greater opportunistic benefit from efficient pollinators than the other two. Moreover, emasculated flowers of the accession with the most exposed stigma (Utah 2) produced the greatest seed set after M. sexta visitation. This study reveals intraspecific variation in pollination syndromes that illuminate the potential of a plant species to adapt to local pollinator communities, changing environments, and altered pollination networks.

An olfactory-specific glutathione-S-transferase in the sphinx moth Manduca sexta

1999 ◽  
Vol 202 (12) ◽  
pp. 1625-1637 ◽  
Author(s):  
M.E. Rogers ◽  
M.K. Jani ◽  
R.G. Vogt
Keyword(s):  
Sex Pheromone ◽  
Manduca Sexta ◽  
Olfactory System ◽  
Phylogenetic Analyses ◽  
Complex Mixture ◽  
Glutathione S Transferase ◽  
Olfactory Sensilla ◽  
Amino Acid Homology ◽  
Specific Mrnas

Insect antennae have a primary function of detecting odors including sex pheromones and plant volatiles. The assumption that genes uniquely expressed in these antennae have an olfactory role has led to the identification of several genes that are integral components of odorant transduction. In the present study, differential display polymerase chain reaction (ddPCR) was used to isolate 25 antennal-specific mRNAs from the male sphinx moth Manduca sexta. Northern blot analyses revealed that one clone, designated G7-9, was antennal-specific and was highly enriched in male antennae relative to female antennae. In situ hybridization indicated that G7-9 expression was restricted to a spatial domain of the olfactory epithelium occupied exclusively by sex-pheromone-sensitive olfactory sensilla. Amino acid homology and phylogenetic analyses identified G7-9 as a glutathione-S-transferase (GST); we have named the full-length clone GST-msolf1. GSTs are known to function primarily in the detoxification of noxious compounds. Spectrophotometric and chromatographic analyses of total GST activity indicate that the endogenous GSTs of male and female antennae can modify trans-2-hexenal, a plant-derived green leaf aldehyde known to stimulate the olfactory system of M. sexta. The restricted localization of GST-msolf1 to sex-pheromone-sensitive sensilla, the fact that the sex pheromone of M. sexta consists of a complex mixture of aldehyde components, and the observation that antennal GSTs can modify an aldehyde odorant suggest that GST-msolf1 may have a role in signal termination. In the light of the more commonly observed role of GSTs in xenobiotic metabolism, we propose that GST-msolf1 may play a dual role of protecting the olfactory system from harmful xenobiotics and inactivating aldehyde odorants, especially components of the M. sexta sex pheromone.

Associative olfactory learning in the moth Manduca sexta

2000 ◽  
Vol 203 (13) ◽  
pp. 2025-2038 ◽  
Author(s):  
K.C. Daly ◽  
B.H. Smith
Keyword(s):  
Comparative Analysis ◽  
Associative Learning ◽  
Manduca Sexta ◽  
Olfactory Learning ◽  
The Other ◽  
Proboscis Extension Response ◽  
Treatment Conditions ◽  
Random Pairing ◽  
Pavlovian Learning ◽  
Proboscis Extension

The proboscis extension response conditioning protocol has been used to explore olfactory-based associative learning in an array of insects. We have monitored a different feeding reflex, which involves activation of the cibarial pump, to demonstrate olfactory learning in the moth Manduca sexta. In the first experiment, four different treatment conditions were used to assess associative (Pavlovian) learning. The results indicate that an excitatory cibarial pump response develops and is retained for at least 24 h only when odor is forward-paired with the presentation of sucrose. Three control treatments, backward pairing, air (no odor) pairing and random pairing, failed to increase the cibarial pump response. However, an excitatory cibarial pump response developed when the backward- and air-paired groups received forward pairing of odor and sucrose on the following day. In contrast, moths experiencing random pairing on day 1 displayed a slower rate of acquisition during forward pairing on day 2, which may indicate inhibition. The second experiment investigated discrimination learning. Two odors were randomly presented, one odor being forward-paired with sucrose (+), the other presented alone (−) in a counterbalanced design. Again, only when odor was forward-paired with sucrose did learning occur. We discuss the implication of these findings for a broader comparative analysis of learning in insects.

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