1,720,976 research outputs found
Strategia riproduttiva di Helicodiceros muscivorus, pianta che attrae con l’inganno gli insetti impollinatori imitando odori di origine animale
No full text
A portable computerized system for long-term electrocardiogram monitoring in marine environments
No full textA digital Holter recorder was modified and assembled with a dedicated portable, water- and
pressure-proof, hydrodynamic protective case to detect
electrocardiograms (ECGs) in marine water on free swimming dolphins (Tursiops truncatus) and human divers using a self-contained underwater breathing
apparatus (SCUBA). Employment of a non-invasive appliance leaves subjects awake and not annoyed by the presence of the instrument. Recordings with a good signal-to-noise ratio were obtained, thus revealing electric events throughout the heart cycle of subjects diving at the water surface level and at depth. Results demonstrate that while dolphins show the already known apnoea diving bradycardia, normoxic-air
breathing subjects display noteworthy increases in heart
rate and atrium ventricular conduction velocity which
likely represent functional adjustments to the
performing of swimming and diving physical exercise.
The instrument appears as a promising diagnostic tool
for future studies in the fields of scuba and apnoea
diving sports, occupational medicine and veterinary
science
Fine structure and distribuition of olfctory sensilla on the antennal flagellum of the blowfly Protophormia terraenovae
No full textModulation of the reflex cardiac response in Protophormia terraenovae to gustatory stimulation
No full textThe results of the present study demonstrate that series of gustatory stimulations can induce shortening of the cardiac cycle in the blowfly, Protophormia terraenovae. This effect is due to a decrease in duration of one of the two phases which compose the cardiac cycle, that is the Fast-phase. No changes in action potential frequency of either phase were evoked by stimulation. The data are discussed in terms of sensory-induced changes in hemolymph circulation, which may function to optimize the insect's performance with respect to a state of alertness
The electrophysiological recordings from the taste chemosensilla of Tabanus nigrovittatus Macquart (Diptera: Tabanidae)
No full textA modified behavioral test for determining the median tarsal acceptance thresholds of field-collected, female Tabanus nigrovittatus Macquart to sugars showed that flies were sensitive to the three major nectar sugars (fructose, sucrose, and glucose, in that order of decreasing sensitivity) whereas galactose, a nonnectar sugar, was not comparably stimulating. Comparisons of various treatment effects on the median tarsal acceptance thresholds showed that for future studies, flies should be fed 10% sucrose before testing, should be starved for 24 h before testing, and they do not have to be pretested for a water response. Electrophysiological recordings showed that gustatory chemosensilla were located on the labellum, tip of labrum, labral food canal, foretarsi, tibia, and antennae. All chemosensilla responded to sugar and salt, whereas only those chemosensilla at the tip of the labrum and those lining the food canal, which normally contact the blood meal, responded to sera and plasma
Distinct phases of memory for habituation to different training patters of olfactory stimulation in the blowfly
No full textMorphology and EAG mapping of the antennal olfactory receptors in Dacus oleae
No full textEAGs were recorded from various locations on the flagellar surface of the antennae of the olive fly Dacus oleae stimulated with compounds of behavioural significance to this species. This information was compared with data on the typology and distribution patterns of the olfactory sensilla. Results showed that: a) 3 types of olfactory sensilla are present on the antennae: long basiconica, short grooved basiconica and trichodea; b) 1‐hexanol, ethanol and volatiles belonging to the oily fraction of the olive pulp are the strongest stimuli, while those of the water fraction are little or not effective; c) EAG amplitude values vary as a function of the recording location on the flagellar surface; d) a significant correlation was found, for 2 stimuli of the oily fraction, between EAG amplitude and population density of long sensilla basiconica, thus suggesting this type as specifically responding to these substances. Morphologie des antennes de Dacus oleae et localisation de leurs récepteurs olfactifs par électroantennogramme Des EAG ont été obtenus en différents points de la surface de flagelles d'antennes de la mouche de l'olive, stimulées par des substances ayant une signification pour le comportement de cette espèce. Ces informations ont été comparées avec les données tirées de la typologie et de la distribution des sensilles olfactives. Les résultats mettent en évidence: a) 3 types de sensilles: longue basiconique, basiconique à petit sillon et trichodes; b) les stimuli les plus puissants de la pulpe sont l'1‐hexanol, l'éthanol et les substances volatiles solubles dans l'huile, tandis que les substances hydrosolubles sont peu ou pas actives; c) une ampleur de l'EAG variant en fonction du lieu d'enregistrement sur la surface du flagelle; d) une corrélation significative pour 2 stimuli liposolubles entre l'amplitude de l'EAG et la densité des longues sensilles basiconiques, ce qui suggère une réaction spécifique de ce type de récepteur à ces substances. 1989 The Netherlands Entomological Societ
Monitoring olfactory reception in blowfly pupae
No full textCardiac activity changes in response to external
sensory stimulation have been described as a sensitive
mean for testing the responsiveness of several species
of adult insects. In the present research study we have
examined if cardiac responses to odour delivery could
be detected in blowfly pupae as well, thus helping in
evaluating their responsiveness to the chemical
properties of the external environment. To this end we
studied the regular activity of heart pupae and its
variations following odour delivery.
Electrocardiograms were recorded on Protophormia
terraenovae blowflies, 48 to 24 hours before adult
emergence. Effects of odour application were tested by
delivering air-containing vapours of ammonia or 1-
hexanol on single pupae by means of a standard
olfactometer.
Regular heart activity consisted of the alternation
of two phases of activity, easily distinguishable on the
basis of opposite polarity and different amplitude and
frequency of electric signals. Odour delivery induced a
constant pattern of heart activity changes, consisting
of an immediate arrest of the phase at a higher signal
frequency, the Fast phase, and a premature setting in
of the phase at a lower signal frequency, the Slow
phase. Odour delivery was ineffective on the activity
pattern of specimens on which functional ablation had
been performed of olfactory organs, i.e. the antennae
and maxillary palps. Results show that the cardiac
response is an effective indicator of olfactory reception
in blowfly pupae, thus representing a useful tool for
testing the biological importance of the chemical
environment during insect development
- …
