We'd like to understand how you use our websites in order to improve them. Register your interest. All toads attempted to maintain their diurnal sum of body temperature within a narrow range. Consequently thermoregulatory behaviour differed according to cloud cover and precipitation. If the sky was clear, toads emerged from their hiding place and exposed themselves to solar radiation during 3—5 h in the morning. Following heliothermic heating during the moring toads retreated to the shade, thereby decreasing body temperature below air temperature.
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Revista Chilena de Historia Natural , Assimilation efficiency in Bufo spinulosus tadpoles Anura: Bufonidae : effects of temperature, diet quality and geographic origin. Results showed that geographic origin did not affect assimilation efficiency, while the relationship observed between temperature and diet quality was significant.
Our results suggest that the effect of temperature on digestive processes is more relevant than its effect on transit time in the digestive tract.
The differences in size at metamorphosis in B spinulosus populations of distinct geographic origin could not be explained by the existence of differences in physiologic digestive capacities. Key words: Bufo spinulosus , tadpoles, assimilation, temperature effects, diet quality effects, geographic origin effects. Nuestros resultados sugieren que para B.
Due to diets of highest nutritional quality generally produce an increase in the rates of growth and differentiation, it is assumed that the amount of energy and nutrients present in high quality foods would be better utilized by tadpoles.
However, the energy that an organism obtain from food is mainly dependent upon its digestion i. Assimilation efficiency reflects the capacity of an organism to metabolize the nutrients present in ingested food and is an important factor in its energy balance Calow Changes in assimilation efficiency have been described in ectotherms, allowing them to utilize different types of foods more efficiently Horn , Benavides el al.
Bufo spinulosus Wiegmann has an extended geographic distribution from the Peruvian-Bolivian highlands to the Chilean and Argentinean Andes Vellard These authors propose also that local abiotic conditions, especially water temperature, could explain the adults morphological divergence observed in individuals from the Tatio population, which represents an extreme in the morphological variation observed for this species.
Concerning larval stages Benavides described that Bufo spinulosus tadpoles from different geographic localities, exposed in laboratory to identical photoperiod, temperature and diet conditions, reach to different sizes at metamorphosis. These results suggest that among populations of this species could be differences in some physiological attributes, and these differences possibly will determine the development and growth of the tadpoles and adults size in this species.
Given the wide geographical distribution of B. Therefore, the inclusion of temperature in studies of dietary assimilation capacity is an important point, which up to date has been scarcely explored. We hypnotized that in B. We predict that tadpole feed with rich nutritional diet and growing at high temperature will show higher assimilation in comparison to tadpoles growing both a lower temperature and a nutritional quality diet. We also predict that will exist differences in assimilation among larval as a function of geographic precedence.
The larvae from El Tatio and Chita were directly collected during spring , while the larvae from Chusmiza and Farellones were obtained via artificial reproduction of individuals collected during spring Once the larvae reached a Gosner stage between 21 and 23 they were randomly placed at a density of 15 individuals mL -1 , in plastic containers of a 1 L capacity and a photoperiod of 12OL. For each temperature treatment and locality of origin, three replicates were used for each of two diet treatments: a low nutritional quality diet LQD consisting in boiled lettuce and a high nutritional quality diet HQD consisting in the microalgae spirulina Wardley Spirulina Plus.
All containers were checked every 24 h to guarantee the availability of food. Water in the containers was changed every 72 h and then the containers were randomly rearranged.
After two weeks each group of tadpoles were transferred to a container with clean water without food. During the following 2 h, the feces produced by each group of tadpoles were collected with a Pasteur pipette.
However, assuming that the absorption of ash is constant for all of the diets and the time remains in water was the same; this type of error is acceptable to determine the comparative assimilation efficiency. The assimilation values for each treatment were calculated as an average of the percent assimilation obtained for each three samples and expressed as percent assimilation efficiency with a standard error.
For the statistical analysis of the results, three-way ANOVAs were used with locality, temperature and diet as the predicting factors. The Tukey test HSD was used to establish differences among samples. Before the experiments, the ash content of the two experimental diets was determined using the same procedure describe above, and the energy content kJ per dry ash weight was determined by combustion in a PARR bomb. The HQD presented lower ash content 6. Because it is possible that the assimilation values obtained in our experiment could be influenced by comparing individuals produced by artificial reproduction Chusmiza and Farellones with individuals collected directly from localities Tatio and Chusmiza , we performed a test in which we compared assimilation values categorizing by two conditions: laboratory or collected larvae.
According that, the above conditions it seems no affect the response evaluated in our experiment. Contrary to our predictions, the individuals from different geographic localities presented similar AE values for both experimental diets. Table 1 , Fig. However, the AE of food was shown to be significantly affected by the environmental temperature, type of diet and by the interaction between temperature and diet Table 1 , Fig.
In this analysis we detected a marginal interaction among locality, diet and temperature that could suggest that assimilation of both diet and temperature regimes could changes depending of locality considered.
In order to explore this possibility this effect, we performed a comparison of estimated marginal means of this interaction by locality, considering temperature and diet.
Take account the above information, we discard locality as a relevant factor in order to explain assimilation differences observed among tadpoles. The AE values obtained for B. These latter values are comparable to our results for B. The spirulina-based diet HQD could be considered to be the more artificial of the two used, in its high AE values are comparable to observed values in other species when artificial diets are used i.
Las barras de error corresponden al EE. Environmental temperature has traditionally been considered as one of the most relevant factors affecting the physiology of poikilotherms Rome et al. This pattern coincides with our results in B. This increase in assimilation performance due to the increase of temperature would cancel the negative effect that the decrease in transit time has on assimilation Elliot However, the digestibility of the HQD is not affected by temperature.
The efforts directed toward understanding and explaining the physiological diversity in animals has been concentrated in comparative studies between species from different habitats. However, very few studies have focused on the intraspecific variability at either the intra- or inter-individual levels. Moreover, studies oriented toward understanding thermal acclimation at the population level are scarce Marquet el al.
The possible geographic variation in the expression of attributes in amphibians, such as growth and its association with temperature, has only recently been included by some authors i. Considering the geographic variation in the digestive physiology of other ectotherms i. However, our results do not support this hypothesis. Although there is a lack of systematic studies on the larvae diet of this species, preliminary data from two localities Tatio and Farellones indicates that the larvae consume algae that are similar in total energy and total nitrogen content Benavides, unpublished data.
Therefore, if the larvae from different studied localities consume equivalent diets, it would be reasonable to assume that their digestive biochemical processes are similar Toloza a. The results of the present study are affected by the use of diets not regularly consumed by the tadpoles.
However, both experimental diets utilized are similar in composition i. Taking into consideration this, our results suggest that the physiological adjustments in the rates of development of the different populations cannot be attributed to assimilation.
Therefore, the explanations for the detected differences in size at metamorphosis of B. We are currently performing research in order to elucidate the effects of geographic variation on life-history traits in this species. The authors would also like to thank Dr. Pablo Sabat and three anonymous referees for their constructive suggestions to the former version of this manuscript. Finally, we would like to give special thanks to Dr.
Mario Rosenmann for his permanent friendship and help. Herpetologica Functional Ecology Oecologia Advances in Ecological Research Society for Experimental Biology Seminar Series Marine Biology Bulletin of Marine Society Croom Helm Ltd. Ediciones Universidad de Chile, Santiago, Chile. Comparative Biochemistry and Physiology 96A: American Zoologist Journal of Zoology London Revista Chilena de Historia Natural Journal of Comparative and Biochemical Physiology B: Copeia Environmental Biology of Fishes 5: International Journal of Environmental and Analytical Chemistry In: Hughes RN ed Diet selection: an interdisciplinary approach to foraging behaviors: Journal of Comparative Physiology B: Fifth edition.
Journal of Evolutionary Biology American Journal of Physiology GG MAB 6. Santiago, Chile. International Review of Hydrobiology Associate Editor: Francisco Bozinovic. Received December 2, ; accepted March 1, Servicios Personalizados Revista.
RESULTS Because it is possible that the assimilation values obtained in our experiment could be influenced by comparing individuals produced by artificial reproduction Chusmiza and Farellones with individuals collected directly from localities Tatio and Chusmiza , we performed a test in which we compared assimilation values categorizing by two conditions: laboratory or collected larvae. Error bars correspond to SE.
Revista Chilena de Historia Natural , Assimilation efficiency in Bufo spinulosus tadpoles Anura: Bufonidae : effects of temperature, diet quality and geographic origin. Results showed that geographic origin did not affect assimilation efficiency, while the relationship observed between temperature and diet quality was significant. Our results suggest that the effect of temperature on digestive processes is more relevant than its effect on transit time in the digestive tract. The differences in size at metamorphosis in B spinulosus populations of distinct geographic origin could not be explained by the existence of differences in physiologic digestive capacities.
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Rhinella spinulosa is a species of toad in the family Bufonidae that is found in the Andean Argentina , Bolivia , Chile , and Peru. It breeds in temporary ponds, altiplano lagoons, and slow flowing streams. Where it occurs it tends to be abundant. From Wikipedia, the free encyclopedia.