An electrophysiological search for pheromones of Aplysia californica

1979 ◽  
Vol 57 (4) ◽  
pp. 781-784 ◽  
Author(s):  
Ronald Chase
Keyword(s):  
Chemical Cues ◽  
Aplysia Californica ◽  
Afferent Activity ◽  
Specific Chemical ◽  
Pleurobranchaea Californica ◽  
Gap Technique ◽  
Sucrose Gap ◽  
Species Specific

Afferent activity of the rhinophore nerve in Aplysia californica was recorded using the sucrose gap technique. Spikes were counted during perfusion of the rhinophore with plain seawater, and during perfusion with seawater that had bathed specimens of either Aplysia californica, Aplysia vaccaria, or Pleurobranchaea californica. Each of the experimental perfusions evoked an approximately equal increase in activity. The results fail to support the hypothesis, derived from earlier electrophysiological experiments, that aggregations of Aplysia in the field are determined by species-specific chemical cues.

Female choice for large body size in the cave molly, Poecilia mexicana (Poeciliidae, Teleostei): influence of species- and sex-specific cues

Behaviour ◽  
2007 ◽  
Vol 144 (10) ◽  
pp. 1147-1160 ◽  
Author(s):  
Jakob Parzefall ◽  
Rüdiger Riesch ◽  
Ingo Schlupp ◽  
Martin Plath
Keyword(s):  
Body Size ◽  
Visual Cues ◽  
Chemical Cues ◽  
Large Body ◽  
Large Body Size ◽  
Specific Chemical ◽  
Stimulus Fish ◽  
Poecilia Mexicana ◽  
Species Specific ◽  
Cave Molly

AbstractPrevious studies revealed that females of a cave form of the livebearing fish Poecilia mexicana (cave molly) have maintained the ancestral visual preference for large males, but — as an adaptation to life in darkness — they have evolved the novel capability to assess male size non-visually. Here we examined the mechanisms by which non-visual mate choice for large body size occurs. Are sex- and species-specific chemical cues involved in this preference for large conspecifics? We gave focal females an opportunity to associate with a large and a small stimulus fish in simultaneous choice tests, whereby the females could perceive either multiple cues (visual plus non-visual) from the stimulus fish, solely non-visual cues in darkness, or solely visual cues. Stimulus fish were two conspecific males, conspecific females, or heterospecific females (Xiphophorus hellerii). Cave molly females showed a significant preference for large conspecific males and for large conspecific females in all treatments. When a large and a small swordtail female were presented, cave molly females showed a preference for the larger fish only when exclusively visual cues from the stimulus fish were available. The non-visual preference for large body size appears to be mediated by species- but not by sex-specific cues, suggesting that species-specific chemical cues play an important role during mate choice.

scholarly journals Drosophila adult and larval pheromones modulate larval food choice

2014 ◽  
Vol 281 (1784) ◽  
pp. 20140043 ◽  
Author(s):  
Jean-Pierre Farine ◽  
Jérôme Cortot ◽  
Jean-François Ferveur
Keyword(s):  
Food Choice ◽  
Food Preference ◽  
Chemical Cues ◽  
Food Sources ◽  
Natural Food ◽  
Larval Food ◽  
Specific Chemical ◽  
Drosophila Buzzatii ◽  
Adult Conspecific ◽  
Species Specific

Insects use chemosensory cues to feed and mate. In Drosophila , the effect of pheromones has been extensively investigated in adults, but rarely in larvae. The colonization of natural food sources by Drosophila buzzatii and Drosophila simulans species may depend on species-specific chemical cues left in the food by larvae and adults. We identified such chemicals in both species and measured their influence on larval food preference and puparation behaviour. We also tested compounds that varied between these species: (i) two larval volatile compounds: hydroxy-3-butanone-2 and phenol (predominant in D. simulans and D. buzzatii , respectively), and (ii) adult cuticular hydrocarbons (CHs). Drosophila buzzatii larvae were rapidly attracted to non-CH adult conspecific cues, whereas D. simulans larvae were strongly repulsed by CHs of the two species and also by phenol. Larval cues from both species generally reduced larval attraction and pupariation on food, which was generally—but not always—low, and rarely reflected larval response. As these larval and adult pheromones specifically influence larval food search and the choice of a pupariation site, they may greatly affect the dispersion and survival of Drosophila species in nature.

scholarly journals Behavioural responses of cane toad (Rhinella marina) adults and tadpoles to chemical cues

2018 ◽  
Vol 45 (2) ◽  
pp. 149-157
Author(s):  
Takashi Haramura
Keyword(s):  
Chemical Cues ◽  
Control Method ◽  
Chemical Substance ◽  
Cane Toad ◽  
Specific Chemical ◽  
Chemical Substances ◽  
Rhinella Marina ◽  
Size At Metamorphosis ◽  
Pheromonal Communication ◽  
Species Specific

Pheromonal communication may be possible to control the invader animal. Pheromone-induced behavioural changes could be exploited to control invasive species such as the cane toad (Rhinella marina). Injured cane toad tadpoles are known to produce species-specific chemical cues that alert conspecific tadpoles to danger. These chemical cues reduce both the survival rate of other tadpoles and body size at metamorphosis, and suggest that cane toad tadpoles express chemical substances that control the behaviour of other tadpoles. Identification of the chemical substance(s) involving in tadpole could lead to the development of methods to control the behaviour of cane toad. Here, the behaviour of cane toad adults and tadpoles was characterized following exposure to chemical substances extracted from dead cane toad tadpoles using methanol (MeOH) or distilled water (H2O). Adult toads showed signs of avoiding water to which the H2O-extracted chemical cue had been added. By contrast, no differences were observed in the swimming behaviour of tadpoles (control, MeOHor H2O-extracted samples). These data indicate that development of a chemicalbased behaviour control method will require more detailed chemical analyses. We used dead tadpoles to extract chemical substrate, but in future studies, the potential behaviour-controlling chemical cues should be extracted from live cane toad tadpoles.Bangladesh J. Zool. 45(2): 149-157, 2017

The induction of diapause in Moina by species-specific chemical cues

2006 ◽  
Vol 41 (2) ◽  
pp. 255-261 ◽  
Author(s):  
Egor Zadereev ◽  
Tatiana Lopatina
Keyword(s):  
Chemical Cues ◽  
Specific Chemical ◽  
Species Specific

AN ANALYSIS OF CONTROL OF THE VENTRICLE OF THE MOLLUSC MERCENARIA MERCENARIA

1993 ◽  
Vol 179 (1) ◽  
pp. 63-75
Author(s):  
C. L. Devlin
Keyword(s):  
Critical Role ◽  
Chloride Concentration ◽  
Mercenaria Mercenaria ◽  
Maximal Effect ◽  
Entry Blocker ◽  
Gap Technique ◽  
High K ◽  
Ionic Mechanisms ◽  
Excitatory Action ◽  
Sucrose Gap

This study focuses on the ionic mechanisms involved in serotonergic control of the ventricle from the mollusc Mercenaria mercenaria. The effects of calcium (Ca2+), sodium (Na+), potassium (K+), magnesium (Mg2+) and chloride (Cl-) ions on the action of 5-hydroxytryptamine (5-HT) were tested using a sucrose-gap technique. 5-HT increased the amplitude and frequency of the cardiac action potentials (APs) and coupled systolic force in a range of concentrations from the threshold, at 10–10 mol l-1, to 10-6 mol l-1. Low, physiological doses of 5-HT increased the rate of rise and amplitude of the fast rising phase of the AP, and hastened the process of repolarization. Doses of 5-HT higher than 10-5 mol l-1 caused systolic arrest. The action of 5-HT was highly dependent on the presence of physiological levels of extracellular Ca2+. It had a maximal effect on systolic activity in a calcium chloride concentration range of 9–18 mmol l-1. The activity of 5-HT was blocked by treatment with Ca2+-free saline, with inorganic Ca2+ blockers (lanthanum or cobalt) or with an organic Ca2+ entry blocker (verapamil). The effects of 5- HT were potentiated by treatment with barium ions (Ba2+), by a dihydropyridine-sensitive Ca2+ agonist, Bay K 8644, or by a vertebrate Ca2+ entry blocker, diltiazem. Removal of extracellular Na+ or treatment with a Na+ ionophore, monensin, did not significantly affect excitation by 10-6 mol l-1 5-HT; nor did the removal of Cl- or Mg2+. Unlike Ca2+, these three ions probably did not have a critical role during the excitatory action of 5-HT. The excitatory action of 5-HT was not significantly altered by treatment with K+-free saline. When the membrane was depolarized by high-K+ salines, however, 5-HT was unable to elicit any APs or systolic contractions, suggesting that its mechanism may involve voltage-sensitive channels.

scholarly journals Blooms of Toxic Cyanobacterium Nodularia spumigena in Norwegian Fjords During Holocene Warm Periods

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 257
Author(s):  
Robert Konkel ◽  
Anna Toruńska-Sitarz ◽  
Marta Cegłowska ◽  
Žilvinas Ežerinskis ◽  
Justina Šapolaitė ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Phytoplankton Community ◽  
Sediment Cores ◽  
Specific Chemical ◽  
Nodularia Spumigena ◽  
History Of ◽  
Recent Sediments ◽  
Species Specific ◽  
Ecosystem Changes ◽  
Deep Sediments

In paleoecological studies, molecular markers are being used increasingly often to reconstruct community structures, environmental conditions and ecosystem changes. In this work, nodularin, anabaenopeptins and selected DNA sequences were applied as Nodularia spumigena markers to reconstruct the history of the cyanobacterium in the Norwegian fjords. For the purpose of this study, three sediment cores collected in Oslofjorden, Trondheimsfjorden and Balsfjorden were analyzed. The lack of nodularin in most recent sediments is consistent with the fact that only one report on the sporadic occurrence and low amounts of the cyanobacterium in Norwegian Fjords in 1976 has been published. However, analyses of species-specific chemical markers in deep sediments showed that thousands of years ago, N. spumigena constituted an important component of the phytoplankton community. The content of the markers in the cores indicated that the biomass of the cyanobacterium increased during the warmer Holocene periods. The analyses of genetic markers were less conclusive; they showed the occurrence of microcystin/nodularin producing cyanobacteria of Nostocales order, but they did not allow for the identification of the organisms at a species level.

Insect–Plant Interactions: A Multilayered Relationship

2020 ◽  
Author(s):  
Garima Sharma ◽  
Praful Ashokrao Malthankar ◽  
Vartika Mathur
Keyword(s):  
Plant Resistance ◽  
Crucial Role ◽  
Chemical Cues ◽  
Defense Responses ◽  
Trophic Levels ◽  
Plant Interactions ◽  
Plant Metabolites ◽  
Specific Chemical ◽  
Plant Interaction ◽  
Morphological Defense

Abstract During herbivory, insects recognize their host plant based on specific chemical cues, whereas the plants induce various chemical and morphological defense responses to resist this attack. However, the seemingly bidirectional insect–plant interaction involves various confounding aspects that influence the performance and fitness of the two participants. These interactions are often mediated by associated microbiota, competitors, predators, and parasitoids that interact in either obligate or facultative manner. Insect endosymbionts play a crucial role in the perception, nutrition, metabolism as well as reproduction of their host, which together determine its survival and fitness on the plant. Endosymbionts also help their host to overcome plant defenses by detoxifying plant metabolites. On the contrary, plant-associated microbes contribute in induced systemic plant resistance by enhancing chemical and morphological defense. These interactions determine the association of insect and plant, not only with the high trophic levels but also with the ecosystem as a whole. Thus, insect–plant interaction is a multilayered relationship extending to various micro- and macro-organisms associated either temporally or spatially. All these relationships may be considered to obtain a wholesome perspective of the natural environment.

scholarly journals Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique

1962 ◽  
Vol 45 (6) ◽  
pp. 1195-1216 ◽  
Author(s):  
Fred J. Julian ◽  
John W. Moore ◽  
David E. Goldman
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Sea Water ◽  
Sucrose Solution ◽  
Chloride Concentration ◽  
Giant Axon ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Gap Technique ◽  
Sucrose Gap

A method similar to the sucrose-gap technique introduced be Stäpfli is described for measuring membrane potential and current in singly lobster giant axons (diameter about 100 micra). The isotonic sucrose solution used to perfuse the gaps raises the external leakage resistance so that the recorded potential is only about 5 per cent less than the actual membrane potential. However, the resting potential of an axon in the sucrose-gap arrangement is increased 20 to 60 mv over that recorded by a conventional micropipette electrode when the entire axon is bathed in sea water. A complete explanation for this effect has not been discovered. The relation between resting potential and external potassium and sodium ion concentrations shows that potassium carries most of the current in a depolarized axon in the sucrose-gap arrangement, but that near the resting potential other ions make significant contributions. Lowering the external chloride concentration decreases the resting potential. Varying the concentration of the sucrose solution has little effect. A study of the impedance changes associated with the action potential shows that the membrane resistance decreases to a minimum at the peak of the spike and returns to near its initial value before repolarization is complete (a normal lobster giant axon action potential does not have an undershoot). Action potentials recorded simultaneously by the sucrose-gap technique and by micropipette electrodes are practically superposable.

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