Energetics of vocalization by an anuran amphibian (Hyla versicolor) (original) (raw)
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The enzymatic basis of high metabolic rates in calling frogs
Physiological zoology, 1985
Oxygen consumption by male spring peepers (Hyia crucifer) increased linearly with calling rate, reaching peak values of 1.5-1.7 ml 02/(g' h) at the highest calling rates. The intercept of the regression line describing the relationship between metabolism and calling rate does not differ significantly from daytime resting metabolism (0.11 ml Oz/[g• h]). Metabolic rate during vigorous locomotor exercise at the same temperature (19 C) was only 1.1 ml Oz/(g• h). We measured activities of mitochondrial enzymes in the trunk muscles (internal and external obliques) involved in sound production and in mixed hind limb muscles of male and female frogs. Male trunk muscles were very large, accounting for 15% of total body mass, whereas female trunk muscle constituted only 3% of total body mass. Citrate synthase (CS) activity in male trunk muscle, indicative of oxidative capacity, was six times the CS activity in leg muscle (86 vs. 14 ~mol/[min. g fresh muscle at 20 C]) and 17 times the CS activity in female trunk muscle (5 ~mol/[min' g fresh muscle]). The capacity to oxidize fat, as indicated by ~-hydroxyacyl-CoA dehydrogenase activity, was five times higher in male trunk muscle than in leg muscle (30 vs. 6 ~mol/[min• g fresh muscle]), suggesting that fatty acid oxidation plays an important role in the energetics of vocalization in this species, Phosphofructokinase activity, a key glycolytic marker, was not significantly different in trunk and leg muscle. The capacity of male spring peeper trunk muscles for aerobic metabolism exceeds considerably the highest values yet reported for ectothermic vertebrate muscle tissue and is comparable to highly oxidative muscles of endotherms.
Calling energetics of a neotropical treefrog, Hyla microcephala
1989
We investigated the calling energetics of Hyla microcephala, a neotropical treefrog with an unusually complex vocal repertoire. Males respond to the calls of other individuals by adding secondary click notes to their calls, thereby increasing the total number of notes given per minute. Rates of oxygen consumption of males calling in metabolic chambers were 0.41-2.80 ml O2/(g-h), corresponding to calling rates of 205-6330 notes/h. Note rate explained 95% of the variance in metabolic rate; the effect of variation in body size and temperature was small. Data from playback experiments with males in the field showed that note rate increased as as the number of notes in a stimulus call increased, and this resulted in substantial increases in the cost of calling. Average metabolic rates for males in the field were about 1.7 ml O2/(g" h), for a net cost of calling of about 20 J/h for an average-size male. However, estimated metabolic rates varied by more than 300% and were strongly influenced by the proximity and calling activity of other males in the chorus. Male H. microeephala appear to conserve energy by reducing calling rates when only a few males are active and increasing calling efforts only when vocal competition among males is intense.
Behavioral Ecology and Sociobiology, 1995
Chorusing males of the neotropical treefrog Hyla rnicrocephala call in distinct bouts punctuated by periods of silence, a pattern known as unison bout singing. Schwartz (1991) previously tested and refuted the hypotheses that males periodically stop calling either because of a female preference for males that call cyclically, or because high ambient noise levels inhibit vocal activity. Males of H. microcephala are vocally responsive to the calls of other males, and during calling bouts their rate of note production can exceed 10,000 per hour. In natural choruses females preferentially pair with males that call at the higher rates. Because females can pair with males over many hours, males may stop calling periodically to save energy so they can continue to call for the entire period that females are available. We directly tested this energy conservation hypothesis by collecting samples of males early in the evening just after chorusing commenced and later when chorusing had ended for the night. Trunk muscles (internal and external oblique), which are responsible for the airflow associated with note production, were dissected, frozen, and their glycogen content measured. Data on calling behavior were obtained for late-evening samples. Individual calling behavior was not correlated with a male's final glycogen level. In addition, many males ended their calling before glycogen reserves were exhausted, indicating that factors other than energy can determine when males finally stop chorusing. However, the biochemical assays supported the energy conserva
Journal of Herpetology, 2006
Vocal advertisement by male anurans can make considerable demands on an individual's energetic reserves and innate physiological resources. In this study, we tested for a relationship between calling and locomotory performance in male Gray Treefrogs, Hyla versicolor. Male vocal activity was monitored in choruses assembled in an artificial pond and call duration and pulse effort used as calling performance metrics. Swimming distance served as our measure of locomotory performance. When males were compared within experimental choruses, there was no tendency for the male that produced the longest calls to swim further than the male that produced the shortest calls. Rather, the opposite was true. When these same males were ranked based on their pulse effort, we found that the male with superior calling performance also performed better in the swimming test than the male that gave fewer total pulses. There was no significant relationship between male condition (weight relative to length) and either calling or swimming performance. We hypothesize that pulse effort, which shows more stability within males under dynamic acoustic situations in choruses than call duration, may better reflect limitations of the cardiovascular and respiratory system than does call duration.
General and Comparative Endocrinology, 2017
In vertebrates, the increase in plasma androgens and corticosteroids is essential for the expression of reproductive behaviour. In male anurans, the interaction between hypothalamus-pituitary-gonadal and hypothalamus-pituitary-interrenal axes plays a pivotal role in calling behaviour and energy mobilisation through the secretion of testosterone and corticosterone respectively. To explain the association among body condition, testosterone, corticosterone and calling behaviour the energetic-hormonevocalisation (EHV) model has been proposed. The model predicts that with continued participation in chorus activity within and across nights, levels of circulating androgens, corticosterone and vocal effort tend to increase and should be positively correlated in calling males. Consequently, decreasing energy reserves should be inversely correlated with corticosterone level in calling males. Depleted energy reserves lead to the peaking of circulating corticosterone, which suppresses androgen production and calling behaviour. In the present study, we used Nyctibatrachus humayuni with unique reproductive behaviour to test the model by quantifying calling behaviour and urinary metabolites of testosterone and corticosterone. We also computed the body condition index to assess the association among energetics, levels of testosterone, corticosterone and calling behaviour. The results show that calling males had higher levels of urinary testosterone metabolites (UTM) than non-calling males indicating the importance of testosterone in controlling the calling behaviour. Surprisingly, urinary corticosterone metabolite (UCM) levels were comparable between calling and non-calling males. Further, calling males had higher body condition estimates than non-calling males. The vocal effort was not associated with UTM, UCM or body condition index (BCI). However, a positive association was observed between UTM and UCM levels in calling males indicating the requirement of higher energy for advertisement. Analysis of UTM and UCM levels throughout the breeding season revealed that breeding basal of UTM was significantly higher than that of UCM. Interestingly, UCM levels were maintained at a lower threshold during the breeding season. These observations are in line with some of the predictions of EHV model.
Metabolic costs of sound production in the oyster toadfish, Opsanus tau
Canadian Journal of Zoology-revue Canadienne De Zoologie, 2002
The energetics of mate calling has been studied in insects, frogs, birds, and mammals, but not in fishes. The oyster toadfish, Opsanus tau, produces a boatwhistle advertisement call using one of the fastest muscles known in vertebrates. Because toadfish will not boatwhistle in a respirometer, we measured oxygen consumption after eliciting sound production by electrically stimulating the sonic swim bladder muscle nerve. Induced sounds were similar to a male calling at a rapid rate. Stimulation of the sonic nerve increased the respiration rate by 40-60% in males, but they became agitated. Repeating the experiment decreased agitation, and in most fish respiration rates approximated control levels by the second or third replication. Elicited sounds and therefore sonic-muscle performance were similar in all repetitions, hence it appears that the increased oxygen consumption in the first trial was caused by the fish's agitation. Controls indicated that electrode implantation and electrical stimulation of the body cavity did not affect the respiration rate. We suggest that allocation of a small amount of the total energy budget to sound production is reasonable in toadfish, and probably most other fish species, because of the small amount of time that the sonic muscles actually contract and their small size (about 1% of body mass).
Journal of Comparative Physiology, 1972
Oxygen consumption and heart rate were measured during rest and activity in the lizards Varanus gouldii and Sauromalus hispidus. Oxygen debt was calculated from postactive oxygen consumption. Standard metabolic rates of the two animals are similar but Varanus consumes much more oxygen during activity than does Sauromalus (Fig. 1-3). The latter has a constant active metabolic rate above 30~ and accumulates a large oxygen debt, which is repayed slowly (Fig. 4). Varanus recovers rapidly from activity (Fig. 5), presumably because of the smaller lactacid debt incurred. Heart rate increment in Sauromalus is high (Fig. 8). This variable cannot be responsible for the limitation of active oxygen consumption; calculations of oxygen pulse suggest that an inability to increase A-V difference and/or stroke volume are implicated (Fig. 9). Varanu~ have evolved mechanisms to sustain high levels of oxygen consumption superior to those of other reptiles investigated. The role of anaerobiosis in the biology of both animals is discussed.
Comparative biochemistry and physiology. A, Comparative physiology, 1974
Oxygen consumption was measured with an automatic constantly recording electrolysis apparatus in leopard frogs (Rum pipiens) acclimated at 15 and 25°C. All groups acclimated under a photoperiod of LD12 : 12 exhibited a distinct diurnal metabolic minimum during the first hour after the onset of the photophase and a significant metabolic maximum rate during the first hour after the onset of the scotophase. 2. Studies of animals conducted under constant light (LL) and darkness (DD) showed a midday metabolic maximum cycle with no pronounced metabolic minimum. 3. Aerobic metabolic scope produced by Faradic stimulation for 30-min periods was thermally dependent and varied with the time of the daily cycle of the shocking process. At 15"C, the mean oxygen consumption above routine metabolism (21.0 ~1 g-l hr-') was significantly lower than the absolute scope at 25°C (36.0 ~1 g-l hr-*). 4. Oxygen debt increased with temperature and varied with the time of day the animals were shocked. Mean oxygen debt at 25°C was 80.7 ~1 Or g-l, 42 per cent higher than at 15°C (56.7 ~10, g-l). Conversion of oxygen debt to lactate yielded corresponding values of 0.98 (15'C) and 140 mg g-l (25°C). Recovery periods for oxygen debts averaged 3.7 hr. 5. The total energetic expenditures during periods of maximal activity above the routine metabolic level were 0.37 cal g-l at 15°C and 0.55 cal g-l at 25°C. Of the energy expended above the routine metabolic rate during strenuous activity, 69 and 73 per cent were supported anaerobically at 25 and lS"C, respectively.