Effect of Diet Viscosity on the Operation of the Pharyngeal Pump in the Blood-Feeding Bug Rhodnius Prolixus

1979 ◽  
Vol 82 (1) ◽  
pp. 93-104
Author(s):  
J. J. B. SMITH
Keyword(s):  
Central Nervous System ◽  
Stroke Volume ◽  
Effective Viscosity ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Feeding Rates ◽  
Artificial Diets ◽  
Maximum Value ◽  
Stretch Receptors ◽  
Diet Viscosity

1. The rate of pumping and total number of pump strokes was recorded whilst Rhodnius prolixus fed on measured amounts of artificial diets. 2. Increasing the viscosity of the diet caused a decline in both the frequency with which the pharyngeal pump operates and the average stroke volume of the pump. 3. In 5th-instar Rhodnius, the stroke volume tends toward a maximum value of about 60 nl at viscosities lower than abeut 3 cP. 4. Feeding rates (volume per unit time) agree with Poiseuille's law at high viscosities, but are less than predicted at low viscosities. 5. The maximum power output of the pump occurs at a viscosity between 1 and 3 cP, which is probably the range of the effective viscosity of blood in tubes with the dimensions of Rhodnius stylets. 6. These results are inconsistent with a hypothesis of a central nervous system ‘oscillator’ controlling the pump muscle, independent of feedback, but are consistent with a model involving peripheral feedback from stretch receptors, with an appropriate delay.

A Practical Apparatus for Feeding Artificial Diets to All Stages of Rhodnius prolixus Stål

1963 ◽  
Vol 95 (4) ◽  
pp. 362-364 ◽  
Author(s):  
W. G. Friend ◽  
Edna Cartwright
Keyword(s):  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Nutritional Requirements ◽  
Feeding Apparatus ◽  
Artificial Diets ◽  
Large Numbers

Before atten~pting to determine the nutritional requirements of Rhodnius prelixus Stål, a blood-feeding reduviid bug, it was necessary to build a feeding apparatus that would permit the insects to feed normally on various artificial diets. Since it was expected that large numbers of animals would have to be fed individually, practical considerations demanded that the feeding apparatus be easy to service and maintain. Some of the experimental diets would be extremely expensive and radioactive and consequently an apparatus that would permit the use of small volumes of diet was required.

Anti-diuresis in the blood-feeding insect Rhodnius prolixus Stål: the peptide CAP2b and cyclic GMP inhibit Malpighian tubule fluid secretion.

1997 ◽  
Vol 200 (17) ◽  
pp. 2363-2367 ◽  
Author(s):  
M C Quinlan ◽  
N J Tublitz ◽  
M J O'Donnell
Keyword(s):  
Cyclic Gmp ◽  
Physiological Role ◽  
Malpighian Tubule ◽  
Fluid Secretion ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Tubule Fluid ◽  
Secretion Rates

Rhodnius prolixus eliminates NaCl-rich urine at high rates following its infrequent but massive blood meals. This diuresis involves stimulation of Malpighian tubule fluid secretion by diuretic hormones released in response to distention of the abdomen during feeding. The precipitous decline in urine flow that occurs several hours after feeding has been thought until now to result from a decline in diuretic hormone release. We suggest here that insect cardioacceleratory peptide 2b (CAP2b) and cyclic GMP are part of a novel mechanism of anti-diuresis. Secretion rates of 5-hydroxytryptamine-stimulated Malpighian tubules are reduced by low doses of CAP2b or cyclic GMP. Maximal secretion rates are restored by exposing tubules to 1 mmol l-1 cyclic AMP. Levels of cyclic GMP in isolated tubules increase in response to CAP2b, consistent with a role for cyclic GMP as an intracellular second messenger. Levels of cyclic GMP in tubules also increase as urine output rates decline in vivo, suggesting a physiological role for this nucleotide in the termination of diuresis.

scholarly journals Changes in antennal gene expression underlying sensory system maturation in Rhodnius prolixus

2021 ◽  
Author(s):  
Jose Manuel Latorre Estivalis ◽  
Ewald Grosse-Wilde ◽  
Gabriel R Fernandes ◽  
Bill S Hansson ◽  
Marcelo Gustavo Lorenzo
Keyword(s):  
Molecular Level ◽  
Expression Profiles ◽  
Sensory System ◽  
Transcript Abundance ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Large Set ◽  
Illumina Platform ◽  
State Dependent ◽  
Host Cues

Background Triatomine bugs are the blood feeding insect vectors transmitting Chagas disease to humans, a neglected tropical disease that affects over 8 million people, mainly in Latin America. The behavioral responses to host cues and bug signals in Rhodnius prolixus are state dependent, i.e., they vary as a function of post-ecdysis age. At the molecular level, these changes in behavior are probably due to a modulation of peripheral and central processes. In the present study, we report a significant modulation of the expression of a large set of sensory-related genes. Results were generated by means of antennal transcriptomes of 5th instar larvae along the first week (days 0, 2, 4, 6 and 8) after ecdysis sequenced using the Illumina platform. Results Age induced significant changes in transcript abundance were established in more than 6,120 genes (54,7 % of 11,186 genes expressed) in the R. prolixus antenna. This was especially true between the first two days after ecdysis when more than 2,500 genes had their expression significantly altered. In contrast, expression profiles were almost identical between day 6 and 8, with only a few genes showing significant modulation of their expression. A total of 86 sensory receptors, odorant carriers and odorant degrading enzymes were significantly modulated across age points and clustered into three distinct expression profiles. Conclusions The set of sensory genes whose expression increased with age (profile 3) may include candidates underlying the increased responsiveness to host cues shown by R. prolixus during the first days after molting. For the first time, we describe the maturation process undergone at the molecular level by the peripheral sensory system is described in an hemimetabolous insect.

Motor responses of Rhodnius prolixus Stål (Hem., Reduviidae) to volatile drugs

1971 ◽  
Vol 61 (2) ◽  
pp. 309-313 ◽  
Author(s):  
Ian McLure
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Carbon Tetrachloride ◽  
Chloral Hydrate ◽  
Rhodnius Prolixus ◽  
The Other ◽  
Motor Responses ◽  
Normal Feeding ◽  
Insect Central Nervous System ◽  
Differential Action

Fifth-instar nymphs of Rhodnius prolixus Stålwere exposed to the vapours of 11 volatile drugs: acetone, bromobenzene, bromoform, carbon tetrachloride, chloral hydrate, chloroform, dioxane, ethanol, ethyl ether, isopropanol and paraldehyde. Bromobenzene, bromoform, carbon tetrachloride, chloroform and ether induced reversible anaesthesia. For each of these five, the insects exhibited a different andspecific pattern of motor responses before becoming totally immobile; these responses are described. The responses to carbon tetrachloride are similar to the normal feeding responses of this insect. The other six drugs did not induce anaesthesia, but instead, a commonand stereotyped pattern of cleaning responses, suggesting irritation of the sensory organs. It is proposed that the agent-specific responses to the anaesthesiainducing drugs are due to their differential action upon specific portions of the insect central nervous system.

Maintenance of Simulium Wilhelmia lineatum Meigen and Simulium erythrocephalum de Geer through successive generations in the laboratory

1984 ◽  
Vol 62 (5) ◽  
pp. 870-877 ◽  
Author(s):  
P. J. Ham ◽  
A. E. Bianco
Keyword(s):  
Egg Production ◽  
Blood Feeding ◽  
Water Systems ◽  
Feeding Rates ◽  
Fertility Rates ◽  
Bovine Blood ◽  
Circulating Water ◽  
Development Period ◽  
Successive Generations ◽  
Egg Fertility

With the use of circulating water systems to rear larvae, Simulium erythrocephalum and S. lineatum have been continuously maintained through to the F7 and F3 generations, respectively. Insemination rates of 100% were obtained for both species by the F2 generation. Using chick skin membranes and bovine blood, mean blood-feeding rates of 56 and 87% were achieved for S. lineatum and S. erythrocephalum, respectively. Mean egg production and egg fertility rates increased after the parental generation was produced. Mating trials were peformed to assess conditions for optimum insemination rates. A significant correlation between temperature and complete generation development period was observed.

Ultrastructural changes in posterior midgut cells associated with blood feeding in adult female Rhodnius prolixus Stal (Hemiptera: Reduviidae)

1983 ◽  
Vol 61 (11) ◽  
pp. 2574-2586 ◽  
Author(s):  
P. F. Billingsley ◽  
A. E. R. Downe
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Blood Meal ◽  
Apical Cell ◽  
Blood Feeding ◽  
Rhodnius Prolixus ◽  
Ultrastructural Changes ◽  
Dense Matrix ◽  
Apical Surface ◽  
Posterior Midgut

Modifications of posterior midgut cells of Rhodnius prolixus following a meal of rabbit blood are described. Prominent stacks and whorls of rough endoplasmic reticulum become redistributed following a blood meal but later reform during the postfeeding period. Lysosomes undergo internal structural changes and apparent fluctuations in their number per cell as a result of blood meal ingestion. Before blood feeding, the apical surface of the midgut cells show a typical arrangement of a plasma membrane covered on the lumenal surface by a glycocalyx. After a blood meal, a more complex organisation appears, consisting of two plasma membranes separated by an electron-dense matrix. The lumenal apical membrane proliferates during the digestion period to form loosely organised extracellular membrane layers which may function as a peritrophic membrane. Changes in the rough endoplasmic reticulum and lysosomes and modifications to the apical cell surface appear to coincide with previously described proteinase activity cycles in the posterior midgut of R. prolixus. The implications of these results are discussed and are compared with similar ultrastructural events from haematophagous Diptera.

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