scholarly journals Neural and behavioural responses of the pollen-specialist bee Andrena vaga to Salix odours

2021 ◽  
Author(s):  
Hannah Burger ◽  
Melanie Marquardt ◽  
Katharina Babucke ◽  
Kim C. Heuel ◽  
Manfred Ayasse ◽  
...  
Keyword(s):  
Visual Cues ◽  
Floral Scent ◽  
Effective Means ◽  
High Sensitivity ◽  
Host Finding ◽  
Food Sources ◽  
Small Range ◽  
Behavioural Activity ◽  
Electroantennographic Detection ◽  
Behavioural Experiments

An effective means of finding food is crucial for organisms. Whereas specialized animals select a small number of potentially available food sources, generalists use a broader range. Specialist (oligolectic) bees forage on a small range of flowering plants for pollen and use primarily olfactory and visual cues to locate their host flowers. So far, however, little is known about the specific cues oligoleges use to discriminate between hosts and non-hosts and how floral scent compounds of hosts and non-hosts are processed in the bees’ olfactory system. In this study, we recorded physiological responses of the antennae (electroantennographic detection coupled to gas chromatography GC-EAD) and in the brain (optical imaging, GC-imaging), and studied host-finding behaviour of oligolectic Andrena vaga bees, a specialist on Salix plants. In total, we detected 37 physiologically active compounds in host and non-host scents. 4-Oxoisophorone, a common constituent in the scent of many Salix species, evoked strong responses in the antennal lobe glomeruli of A. vaga, but not the generalist honeybee Apis mellifera. The specific glomerular responses to 4-oxoisophorone in natural Salix scents reveals a high degree of specialization in A. vaga for this typical Salix odorant component. In behavioural experiments, we found olfactory cues to be the key attractants for A. vaga to Salix hosts, which are also used to discriminate between hosts and non-hosts, and demonstrated a behavioural activity for 4-oxoisophorone. A high sensitivity to floral scents enables the specialized bees to effectively find flowers and it appears that A. vaga bees are highly tuned to 4-oxoisophorone at a very low concentration.

scholarly journals Flowers of Deceptive Aristolochia microstoma Are Pollinated by Phorid Flies and Emit Volatiles Known From Invertebrate Carrion

2021 ◽  
Vol 9 ◽  
Author(s):  
Thomas Rupp ◽  
Birgit Oelschlägel ◽  
Katharina Rabitsch ◽  
Hafez Mahfoud ◽  
Torsten Wenke ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Floral Scent ◽  
Ground Level ◽  
Food Sources ◽  
Dynamic Headspace ◽  
Sexual Deception ◽  
Flower Visitor ◽  
Experimental Approaches ◽  
Phorid Flies

Deceptive flowers decoy pollinators by advertising a reward, which finally is not provided. Numerous deceptive plants are pollinated by Diptera, but the attractive cues and deceptive strategies are only identified in a few cases. A typical fly-deceptive plant genus is Aristolochia, which evolved sophisticated trap flowers to temporarily capture pollinators. Though rarely demonstrated by experimental approaches, Aristolochia species are believed to chemically mimic brood sites, food sources for adult flies, or utilize sexual deception. Indeed, for most species, studies on scent composition and attractive signals are lacking. In this study, we focused on Aristolochia microstoma, a peculiar Greek endemic with flowers that are presented at ground level in the leaf litter or between rocks and are characterized by a unique morphology. We analyzed flower visitor and pollinator spectra and identified the floral scent composition using dynamic headspace and gas chromatography coupled to mass spectrometry (GC/MS). Female and male phorid flies (Phoridae) are the exclusive pollinators, although the flowers are also frequently visited by Sciaridae, as well as typical ground-dwelling arthropods, such as Collembola and arachnids. The carrion-like floral scent mainly consists of the oligosulphide dimethyldisulfide and the nitrogen-bearing compound 2,5-dimethylpyrazine. These compounds together are known to be released from decomposing insects, and thus, we conclude that pollinators are likely deceived by chemical imitation of invertebrate carrion, a deceptive strategy not described from another plant species so far.

scholarly journals Ants Sense, and Follow, Trail Pheromones of Ant Community Members

Insects ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 383 ◽  
Author(s):  
Jaime M. Chalissery ◽  
Asim Renyard ◽  
Regine Gries ◽  
Danielle Hoefele ◽  
Santosh Kumar Alamsetti ◽  
...  
Keyword(s):  
Trail Pheromone ◽  
Food Sources ◽  
Lasius Niger ◽  
Trail Following ◽  
Harvester Ants ◽  
Community Members ◽  
Trail Pheromones ◽  
Ant Community ◽  
Carpenter Ants ◽  
Electroantennographic Detection

Ants deposit trail pheromones that guide nestmates to food sources. We tested the hypotheses that ant community members (Western carpenter ants, Camponotus modoc; black garden ants, Lasius niger; European fire ants, Myrmica rubra) (1) sense, and follow, each other’s trail pheromones, and (2) fail to recognize trail pheromones of allopatric ants (pavement ants, Tetramorium caespitum; desert harvester ants, Novomessor albisetosus; Argentine ants, Linepithema humilis). In gas chromatographic-electroantennographic detection analyses of a six-species synthetic trail pheromone blend (6-TPB), La. niger, Ca. modoc, and M. rubra sensed the trail pheromones of all community members and unexpectedly that of T. caespitum. Except for La. niger, all species did not recognize the trail pheromones of N. albisetosus and Li. humilis. In bioassays, La. niger workers followed the 6-TPB trail for longer distances than their own trail pheromone, indicating an additive effect of con- and hetero-specific pheromones on trail-following. Moreover, Ca. modoc workers followed the 6-TPB and their own trail pheromones for similar distances, indicating no adverse effects of heterospecific pheromones on trail-following. Our data show that ant community members eavesdrop on each other’s trail pheromones, and that multiple pheromones can be combined in a lure that guides multiple species of pest ants to lethal food baits.

scholarly journals Design, Optimization, and Experiment on a Bioinspired Jumping Robot with a Six-Bar Leg Mechanism Based on Jumping Stability

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Ziqiang Zhang ◽  
Bin Chang ◽  
Jing Zhao ◽  
Qi Yang ◽  
Xingkun Liu
Keyword(s):  
Dynamic Models ◽  
Rotation Angle ◽  
High Sensitivity ◽  
Optimization Method ◽  
Small Range ◽  
Configuration Optimization ◽  
Inertia Moment ◽  
Object A ◽  
Reduced Mechanism ◽  
Optimization Parameters

A jumping leg with one degree of freedom (DOF) is characterized by high rigidity and simple control. However, robots are prone to motion failure because they might tip over during the jumping process due to reduced mechanism flexibility. Mechanism design, configuration optimization, and experimentation were conducted in this study to achieve jumping stability for a bioinspired robot. With locusts as the imitated object, a one-DOF jumping leg mechanism was designed taking Stephenson-type six-bar mechanism as reference, and kinematic and dynamic models were established. The rotation angle of the trunk and the total inertia moment were used as stability criteria, and the sensitivity of different links to the target was analyzed in detail. With high-sensitivity link lengths as the optimization parameters, a configuration optimization method based on the particle swarm optimization algorithm was proposed in consideration of the different constraint conditions of the jumping leg mechanism. Optimization results show that this method can considerably improve optimization efficiency. A prototype of the robot was developed, and the experiment showed that the optimized trunk rotation angle and total inertia moment were within a small range and can thus meet the requirements of jumping stability. This work provides a reference for the design of jumping and legged robots.

scholarly journals Global Survey of Canonical Aspergillus flavus G Protein-Coupled Receptors

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Katharyn J. Affeldt ◽  
Joseph Carrig ◽  
Meareg Amare ◽  
Nancy P. Keller
Keyword(s):  
G Protein ◽  
Aspergillus Flavus ◽  
Effective Means ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
G Protein Coupled Receptors ◽  
Food Sources ◽  
Economic Losses ◽  
Content Type ◽  
G Protein Coupled

ABSTRACTG protein-coupled receptors (GPCRs) are transmembrane receptors that relay signals from the external environment inside the cell, allowing an organism to adapt to its surroundings. They are known to detect a vast array of ligands, including sugars, amino acids, pheromone peptides, nitrogen sources, oxylipins, and light. Despite their prevalence in fungal genomes, very little is known about the functions of filamentous fungal GPCRs. Here we present the first full-genome assessment of fungal GPCRs through characterization of null mutants of all 15 GPCRs encoded by the aflatoxin-producing fungusAspergillus flavus. All strains were assessed for growth, development, ability to produce aflatoxin, and response to carbon sources, nitrogen sources, stress agents, and lipids. Most GPCR mutants were aberrant in one or more response processes, possibly indicative of cross talk in downstream signaling pathways. Interestingly, the biological defects of the mutants did not correspond with assignment to established GPCR classes; this is likely due to the paucity of data for characterized fungal GPCRs. Many of the GPCR transcripts were differentially regulated under various conditions as well. The data presented here provide an extensive overview of the full set of GPCRs encoded byA. flavusand provide a framework for analysis in other fungal species.IMPORTANCEAspergillus flavusis an opportunistic pathogen of crops and animals, including humans, and it produces a carcinogenic toxin called aflatoxin. Because of this,A. flavusaccounts for food shortages and economic losses in addition to sickness and death. Effective means of combating this pathogen are needed to mitigate its deleterious effects. G protein-coupled receptors (GPCRs) are often used as therapeutic targets due to their signal specificity, and it is estimated that half of all drugs target GPCRs. In fungi such asA. flavus, GPCRs are likely necessary for sensing the changes in the environment, including food sources, developmental signals, stress agents, and signals from other organisms. Therefore, elucidating their functions inA. flavuscould identify ideal receptors against which to develop antagonists.

Direct and indirect resistance of sugarcane to Diatraea saccharalis induced by jasmonic acid

2017 ◽  
Vol 107 (6) ◽  
pp. 828-838 ◽  
Author(s):  
P.A. Sanches ◽  
F. Santos ◽  
M.F.G.V. Peñaflor ◽  
J.M.S. Bento
Keyword(s):  
Jasmonic Acid ◽  
Plant Volatiles ◽  
Visual Cues ◽  
Underlying Mechanism ◽  
Host Finding ◽  
Specialist Herbivore ◽  
Sugarcane Borer ◽  
Diatraea Saccharalis ◽  
Induced Defences ◽  
Potential Strategy

AbstractTreating plants with synthetic jasmonic acid (JA) induces a defensive response similar to herbivore attack, and is a potential strategy for integrated pest management. Despite the importance of sugarcane, its JA-induced defences have not yet been studied. We investigated the effects of JA treatment on the direct and indirect resistance of sugarcane to the key-pest and specialist herbivore Diatraea saccharalis and the generalist Spodoptera frugiperda. Indirect defences were examined by testing the attraction of Cotesia flavipes, a sugarcane-borer parasitoid, to JA-induced volatile. The results showed that JA-treated sugarcane did not affect the weight gain of the two larvae. However, in dual-choice assays, both species preferred to feed on mock rather than JA-treated plants. Leaf colorimetric analyses showed that visual cues are unlikely to be involved in larval preference, whereas results from olfactometric assays revealed that D. saccharalis preferred JA-induced over mock plant volatiles. After 48 h of treatment, JA-treated plants emitted a volatile blend attractive to C. flavipes, comprised mainly of sesquiterpenes. However, the parasitoid did not discriminate JA-treated from host-damaged plant volatiles. When the wasps were given a choice between JA-treated and JA-treated + host-damaged plants, they preferred the latter, which emitted a more complex blend, suggesting that JA treatment likely does not hamper host-finding. We concluded that JA induces the emission of volatiles that are attractive to the sugarcane borer parasitoid, as well as an antixenosis type of resistance in sugarcane against the two pests, although neither volatiles nor visual cues alone are involved in the underlying mechanism.

scholarly journals Polarized light use in the nocturnal bull ant, Myrmecia midas

2017 ◽  
Vol 4 (8) ◽  
pp. 170598 ◽  
Author(s):  
Cody A. Freas ◽  
Ajay Narendra ◽  
Corentin Lemesle ◽  
Ken Cheng
Keyword(s):  
Visual Cues ◽  
Polarized Light ◽  
Food Sources ◽  
Light Change ◽  
Polarization Pattern ◽  
Returning Home

Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas . We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1−2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

scholarly journals Nocturnal pollination: an overlooked ecosystem service vulnerable to environmental change

2020 ◽  
Vol 4 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Callum J. Macgregor ◽  
Alison S. Scott-Brown
Keyword(s):  
Environmental Change ◽  
Ecosystem Service ◽  
Visual Cues ◽  
Floral Scent ◽  
Wild Plants ◽  
Future Research ◽  
Night Time ◽  
Pollination Services ◽  
Pollen Vectors ◽  
Conservation Concern

Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.

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