scholarly journals Blood as fuel: the metabolic cost of pedestrian locomotion in Rhodnius prolixus

2020 ◽  
pp. jeb.227264
Author(s):  
Miguel Leis ◽  
Claudio R. Lazzari
Keyword(s):  
Metabolic Rate ◽  
Water Loss ◽  
Carbon Dioxide Emission ◽  
Metabolic Cost ◽  
Rhodnius Prolixus ◽  
Respiratory Pattern ◽  
Energetic Cost ◽  
Active Movement ◽  
Blood Sucking ◽  
Energetic Expenditure

Active searching for vertebrate blood is a necessary activity for haematophagous insects, and it can be assumed that this search should also be costly in terms of energetic expenditure. Either if it is by swimming, walking, running or flying, active movement requires energy, increasing metabolic rates relative to resting situations. We analysed the respiratory pattern and the energetic cost of pedestrian locomotion in the blood-sucking bug Rhodnius prolixus using flow-through respirometry, by measuring carbon dioxide emission and water loss before, during and after walking. We observed an increase of up to 1.7-fold in the metabolic rate during walking as compared to resting in male R. prolixus and 1.5-fold in females, as well as a change in their respiratory pattern. The last switched from cyclic during resting to continuous, when the insects started to walk, remaining this condition unchanged during locomotion and for several minutes after stopping. Walking induced a significant loss of weight in both, males and females. This can be explained by the increase in both, the metabolic rate and the water loss during walking. These data constitute the first metabolic measures of active hematophagous insects and provide the first insights on the energetic expenditure associated to the active search for blood in this group.

scholarly journals Can energetic expenditure be minimized by performing activity intermittently?

2001 ◽  
Vol 204 (3) ◽  
pp. 599-605 ◽  
Author(s):  
E. Edwards ◽  
T. Gleeson
Keyword(s):  
Oxygen Consumption ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Metabolic Cost ◽  
Energetic Cost ◽  
Unit Distance ◽  
Activity Frequency ◽  
Exercise Period ◽  
S Period ◽  
Energetic Expenditure

Previous research has shown that the energetic expense per unit distance traveled for one bout of short-duration activity is much greater than the energetic expense associated with long-duration activity. However, animals are often seen moving intermittently, with these behaviors characterized by brief bouts of activity interspersed with brief pauses. We hypothesized that, when multiple bouts of brief activity are performed intermittently, the energetic cost per unit distance is less than when only one short bout is performed. Mice were run 1, 2, 3, 5, 9 or 13 times for 15 s at their maximal speed within a 375 s period while enclosed in an open-flow respirometry system on a treadmill. The mice were also run continuously for 375 s. Following the last sprint and the continuous run, the mice remained in the respirometry chamber until their vdot (O2) reached resting levels. Excess exercise oxygen consumption (EEOC), the excess volume of oxygen consumed during the exercise period, increased from 0.03+/−0.01 to 0.40+/−0.02 ml O(2)g(−)(1) (mean +/− s.e.m., N=9) with activity frequency. However, the excess post-exercise oxygen consumption (EPOC), or volume of oxygen consumed during the recovery period, was independent of activity frequency (range 0.91-1.16 ml O(2)g(−)(1)) and accounted for more than 80 % of the total metabolic cost when activity was performed intermittently. Lactate concentration was measured at rest, immediately after running and immediately after recovering from running 1, 5 and 13 times within the 375 s period. After running, [lactate] was significantly higher than resting values, but following recovery, [lactate] had reached resting values. The net cost of activity, C(act), calculated by summing EEOC and EPOC and then dividing by the distance run, decreased significantly from 132+/−38 to 6+/−1 ml O(2)g(−)(1)km(−)(1) as activity frequency increased. When these values for C(act) were compared with the cost of running continuously for the same amount of time, the values were identical. Therefore, we conclude that animals can minimize energetic expenditure by performing brief behaviors more frequently, just as they can minimize these costs if they increase the duration of continuous behaviors.

The role of torpor in the life of Australian arid zone mammals.

2004 ◽  
Vol 26 (2) ◽  
pp. 125 ◽  
Author(s):  
F Geiser
Keyword(s):  
Metabolic Rate ◽  
Mass Loss ◽  
Water Loss ◽  
Arid Zone ◽  
Early Morning ◽  
Energetic Cost ◽  
Adverse Conditions ◽  
Distribution Ranges ◽  
Australian Continent ◽  
Species Specific

Approximately half of the Australian continent is arid and is characterised by low primary productivity, limited supply of food and pronounced daily fluctuations of ambient temperature (Ta). Despite these adverse conditions the diversity of small mammals in the Australian arid zone is high, although their abundance is generally low. The most successful groups of small arid zone mammals are the dasyurid marsupials, native rodents, and insectivorous bats. A probable reason for the success of the insectivorous dasyurids and bats, which must cope with strong fluctuations in food and water availability, is their extensive use of torpor. Mammalian torpor is characterised by substantial reductions of body temperature (Tb) metabolic rate (MR) and water loss. Small arid zone dasyurids use exclusively daily torpor, some even during the reproductive season, when most mammals maintain strict homeothermy. Dasyurids reduce Tb from ~ 35�C during normothermia to ~ 15�C during torpor, the MR during torpor (TMR) is ~ 30% of basal metabolic rate (BMR). Mass loss, and thus water loss, is related to the duration of torpor bouts. Dasyurids usually enter torpor at night or in the early morning and arouse around midday or in the afternoon. Recent evidence shows that desert dasyurids may bask in the sun during rewarming from torpor. This can minimise energetic cost of arousal to a fraction of that required for endogenous warming. Arid zone bats are also likely to use torpor extensively, but few species, specific to the arid zone, have been studied. Nevertheless, widely distributed bats that occur in the arid zone, such as Nyctophilus geoffroyi, enter brief torpor for part of the day in summer and prolonged torpor (hibernation) for up to two weeks in winter and can reduce Tb to a minimum of 2 - 3�C and TMR to ~ 3% of BMR; mass loss and water loss are minimal during torpor. Patterns of torpor similar to those in bats also have been observed in the insectivorous echidnas and two species of insectivorous / nectarivorous pygmy-possums, which have distribution ranges that include semi-arid and arid areas. In contrast to these species, no detailed information is available on torpor in native Australian rodents, because little work with respect to torpor has been conducted in Australia. However, many arid zone rodents on other continents employ torpor and it is likely that Australian rodents do as well. In addition to reducing energy expenditure and water loss, use of torpor also appears to prolong life span. This is important for bridging adverse conditions and for subsequent re-colonization of areas after droughts and fires in inland Australia. Thus it appears that the success of small insectivorous/nectarivorous mammals and perhaps rodents in the Australian arid zone is partially due to their use of torpor.

scholarly journals The climbing organ of an insect, Rhodnius prolixus (Hemiptera; Reduviidœ)

1932 ◽  
Vol 111 (772) ◽  
pp. 364-376 ◽  
Keyword(s):  
Mode Of Action ◽  
Ventral Surface ◽  
Rhodnius Prolixus ◽  
Blood Sucking ◽  
New Type

Adhesive or climbing organs are familiar structures in many groups of insects. Most commonly, as in Hymenoptera, Diptera and many Hemiptera, they take the form of empodia or pulvilli between the tarsal claws; in a few Hemiptera they occur at the lower end of the tibia (Weber, 1930), while in many Coleoptera and Orthoptera it is the ventral surface of the tarsal segments themselves which is specially modified (Dewitz, 1884). These structure are generally stated to be absent in the Reduviidæ, but one of us (Gillett, 1932) has recently observed a new type of climbing organ in the blood-sucking reduviid bug, Rhodnius prolixus stål. The object of the present paper is to describe the structure of this organ and to discuss its mode of action.

Hydrogen peroxide detoxification in the midgut of the blood-sucking insect,Rhodnius prolixus

2001 ◽  
Vol 48 (2) ◽  
pp. 63-71 ◽  
Author(s):  
Marcia Cristina Paes ◽  
Mariana Borges Oliveira ◽  
Pedro L. Oliveira
Keyword(s):  
Hydrogen Peroxide ◽  
Rhodnius Prolixus ◽  
Blood Sucking

scholarly journals THE EFFECT OF COLCHICINE ON MYOGENESIS IN VIVO IN RANA PIPIENS AND RHODNIUS PROLIXUS (HEMIPTERA)

1968 ◽  
Vol 39 (3) ◽  
pp. 544-555 ◽  
Author(s):  
Robert H. Warren
Keyword(s):  
Cell Shape ◽  
Rana Pipiens ◽  
Colchicine Treatment ◽  
Rhodnius Prolixus ◽  
Microtubule Disruption ◽  
Blood Sucking ◽  
Tadpole Tail ◽  
Differentiation And Dedifferentiation ◽  
Regeneration Blastema

The effect of colchicine on myogenesis in vivo has been studied in the regenerating tadpole tail of the frog, Rana pipiens, and in the abdominal molting muscles of a blood-sucking bug, Rhodnius prolixus Stål. Colchicine is shown to disrupt microtubules in the differentiating muscle cells of both these organisms. The disruption of microtubules is correlated with a loss of longitudinal anisometry in the myoblasts and myotubes of the regeneration blastema in the tadpole tail. Before colchicine treatment, the myotubes contain longitudinally oriented myofibrils. After colchicine treatment, rounded, multinucleate myosacs containing randomly oriented myofibrils are present. It is suggested that the primary function of microtubules in myogenesis in the Rana pipiens tadpole is the maintenance of cell shape. The abdominal molting muscles of Rhodnius undergo repeated phases of differentiation and dedifferentiation of the sarcoplasm. However, the longitudinal anisometry of the muscle fibers is maintained in all phases by the attachments of the ends of the fibers to the exoskeleton, and microtubule disruption does not alter cell shape. The orientation of the developing myofibrils is also unaltered, indicating that the microtubules do not directly align or support the myofibrils in this system.

scholarly journals Purification and characterization of prolixin S (nitrophorin 2), the salivary anticoagulant of the blood-sucking bug Rhodnius prolixus

1995 ◽  
Vol 308 (1) ◽  
pp. 243-249 ◽  
Author(s):  
J M C Ribeiro ◽  
M Schneider ◽  
J A Guimarães
Keyword(s):  
Cation Exchange ◽  
Salivary Glands ◽  
Coagulation Factor ◽  
Rhodnius Prolixus ◽  
Exchange Chromatography ◽  
Factor X ◽  
Blood Sucking ◽  
Weak Cation Exchange ◽  
Haem Protein ◽  
Strong Cation Exchange Chromatography

The salivary anticoagulant of the blood-sucking bug Rhodnius prolixus was purified to homogeneity using a protocol consisting of weak cation-exchange, DEAE, hydrophobic-interaction and octadecyl reverse-phase chromatography, yielding a protein with the same N-terminal sequence as nitrophorin 2, one of the four NO haem protein carriers present in the salivary glands of Rhodnius with a molecular mass of 19689 Da [D. Champagne, R.H. Nussenzveig and J.M.C. Ribeiro, (1995) J. Biol. Chem. 270, in the press]. To exclude the possibility of the nitrophorin being a contaminant, another chromatographic protocol was performed, consisting of chromatofocusing followed by strong-cation-exchange chromatography. Again the anticoagulant was eluted with nitrophorin 2. Nitrophorin 2 inhibits coagulation Factor VIII-mediated activation of Factor X and accounts for all the anti-clotting activity observed in Rhodnius salivary glands.

scholarly journals Elastic energy savings and active energy cost in a simple model of running

2021 ◽  
Vol 17 (11) ◽  
pp. e1009608
Author(s):  
Ryan T. Schroeder ◽  
Arthur D. Kuo
Keyword(s):  
Elastic Energy ◽  
Energy Cost ◽  
Energy Savings ◽  
Mechanical Energy ◽  
Metabolic Cost ◽  
The Body ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Mass Model ◽  
Human Running

The energetic economy of running benefits from tendon and other tissues that store and return elastic energy, thus saving muscles from costly mechanical work. The classic “Spring-mass” computational model successfully explains the forces, displacements and mechanical power of running, as the outcome of dynamical interactions between the body center of mass and a purely elastic spring for the leg. However, the Spring-mass model does not include active muscles and cannot explain the metabolic energy cost of running, whether on level ground or on a slope. Here we add explicit actuation and dissipation to the Spring-mass model, and show how they explain substantial active (and thus costly) work during human running, and much of the associated energetic cost. Dissipation is modeled as modest energy losses (5% of total mechanical energy for running at 3 m s-1) from hysteresis and foot-ground collisions, that must be restored by active work each step. Even with substantial elastic energy return (59% of positive work, comparable to empirical observations), the active work could account for most of the metabolic cost of human running (about 68%, assuming human-like muscle efficiency). We also introduce a previously unappreciated energetic cost for rapid production of force, that helps explain the relatively smooth ground reaction forces of running, and why muscles might also actively perform negative work. With both work and rapid force costs, the model reproduces the energetics of human running at a range of speeds on level ground and on slopes. Although elastic return is key to energy savings, there are still losses that require restorative muscle work, which can cost substantial energy during running.

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