Field metabolic rates and water influxes of two sympatric Gerbillidae:Gerbillus allenbyi andG. pyramidum

Degen, A. Allan; Pinshow, Berry; Kam, Michael

doi:10.1007/bf01875454

Cited by 28 publications

(3 citation statements)

References 35 publications

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“…Seasonal water influx in three gerbilline species, P. obesus, G. pyramidum and G. allenbyi, showed that water influx was higher in winter than in summer and indicated that the rodents were consuming a more moist diet in winter (Degen, Pinshow & Ilan 1990;Degen, Pinshow & Kam 1992). Indeed, Atriplex halimus leaves, the sole diet consumed by P. obesus, are more succulent in winter than in summer (Degen et al 1990) and the two Gerbillus species consume a higher proportion of green vegetation to seeds in winter than in summer (Bar et al 1984).…”

Section: Water Influxmentioning

confidence: 99%

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

et al. 1997

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1. Desert gerbilline rodents consume mainly plant material, in particular seeds. However, seeds are less available following winter rains than in summer and many rodents shift their diets from predominantly seeds to ones containing more vegetation. This shift results in a proportionately greater preformed water intake and, as these rodents do not drink, an increase in the water influx to field metabolic rate ratio (WI : FMR; ml kJ–1). Thus, this ratio is indicative of the food consumed, being low when gerbils are consuming seeds and high when consuming green vegetation. 2. Smaller animals are more dependent on a highly digestible, high energy diet such as seeds and are more vulnerable to extreme air temperatures than are larger animals. It was predicted that: (1) gerbils consume less seeds in winter than in summer but the difference between seasons in seed intake is less pronounced in smaller than in larger rodents; and (2) smaller gerbils are more sensitive to extreme air temperatures than are larger gerbils. To examine these hypotheses, two coexisting desert gerbils, Gerbillus henleyi (8–12 g) and Meriones crassus (50–110 g), were studied. 3. It was predicted that: (1) the WI : FMR ratio would be greater in winter than in summer in both species, but the proportionate increase would be smaller in G. henleyi than in M. crassus; and (2) energy expenditure would be greater in winter than in summer in both species, but the proportionate increase would be greater in G. henleyi than in M. crassus. To test these predictions, winter and summer water influx and field metabolic rates in these species were measured under free‐living conditions using doubly labelled water. 4. The WI : FMR ratio in summer was 0·048 in G. henleyi and 0·069 in M. crassus, indicating that G. henleyi was consuming proportionately more seeds than M. crassus. In winter, the ratio was 0·052 in G. henleyi, indicating that there was little change in dietary composition and that this species was still consuming mainly seeds. In contrast, the ratio in M. crassus rose to 0·127, indicating a shift to a diet containing more green vegetation. The relatively higher seed intake by G. henleyi than M. crassus in both seasons and the small, if any, seasonal change in seed intake in G. henleyi agrees with the hypothesis of body size and seed intake in gerbils. Winter FMR increased over summer FMR in both species, as predicted; however, the expected greater increase in G. henleyi relative to M. crassus did not occur. The winter FMR was 1·52 times the summer FMR in G. henleyi and 1·53 times the summer FMR in M. crassuss.

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Section: Water Influxmentioning

confidence: 99%

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

et al. 1997

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“…However, most lineages that occurred in at least three samples were not restricted to a single host species. The ability of bacteria to persist in different gerbil species may be a result of the close phylogenetic distance among the three host species [45] , [46] , their similar macro-habitat preferences and overlapping geographical distributions [47] , their infestation by the same arthropod species [32] and their adaptations to the extreme conditions of the sandy desert [48] .…”

Section: Discussionmentioning

confidence: 99%

Association of Host and Microbial Species Diversity across Spatial Scales in Desert Rodent Communities

et al. 2014

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Relationships between host and microbial diversity have important ecological and applied implications. Theory predicts that these relationships will depend on the spatio-temporal scale of the analysis and the niche breadth of the organisms in question, but representative data on host-microbial community assemblage in nature is lacking. We employed a natural gradient of rodent species richness and quantified bacterial communities in rodent blood at several hierarchical spatial scales to test the hypothesis that associations between host and microbial species diversity will be positive in communities dominated by organisms with broad niches sampled at large scales. Following pyrosequencing of rodent blood samples, bacterial communities were found to be comprised primarily of broad niche lineages. These communities exhibited positive correlations between host diversity, microbial diversity and the likelihood for rare pathogens at the regional scale but not at finer scales. These findings demonstrate how microbial diversity is affected by host diversity at different spatial scales and suggest that the relationships between host diversity and overall disease risk are not always negative, as the dilution hypothesis predicts.

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“…Following the winter rains, a major seed production pulse occurs in the spring (March – May), which gradually depletes thereafter (Rosenzweig and Abramsky 1997). Seasonal variations in ambient conditions coupled with the physiological state of individuals may also affect gerbil activity patterns (Degen et al 1992). Predation risk also may vary seasonally with, for example, snakes being active mostly in the summer (Kotler et al 1992).…”

Section: The Study Systemmentioning

confidence: 99%

The role of site, habitat, seasonality and competition in determining the nightly activity patterns of psammophilic gerbils in a centrifugally organized community

Wasserberg¹,

Kotler²,

Abramsky³

2006

Oikos

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Z. 2006. The role of site, habitat, seasonality and competition in determining the nightly activity patterns of psammophilic gerbils in a centrifugally organized community. Á/ Oikos 112: 573 Á/579.Major ecological forces affecting diel activity patterns include predation, competition, resource dynamics, and ambient conditions. In this work we studied if, how, and why the nocturnal activity patterns of two gerbil species differed with respect to site, habitat, season, and inter-specific competition. The study system included two gerbil speciesGerbillus pyramidum and G. andersoni allenbyi in a sandy landscape composed of three habitats-shifting, semi-stabilized, and stabilized sand habitats. Conforming to previous studies, in the semi-stabilized sand habitat clear temporal partitioning in activity times occurred, with G. pyramidum being active earlier in the night and G. a. allenbyi being active in the later part of the night. As shown in previous studies in a different, more xeric site, removal of G. pyramidum demonstrated that this activity pattern is the result of interference competition by the latter on the former. Nocturnal activity pattern differed between habitats and seasons. Temporal partitioning occurred in the semistabilized sand habitat where both gerbil species were common. In the shifting sand habitat, G. pyramidum activity pattern was similar to that in the semi-stabilized sand habitat, but at a lower level. In the stabilized sand habitat where G. a. allenbyi occurred alone, its activity was the highest among the three habitats and was fairly constant throughout the night. Temporal partitioning occurred in the fall and early summer, but not in the early spring. The roles of predation risk, competition and resource dynamics in determining the gerbils' temporal activity together with their implications for community structure, are discussed.

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Field metabolic rates and water influxes of two sympatric Gerbillidae:Gerbillus allenbyi andG. pyramidum

Cited by 28 publications

References 35 publications

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

Body size, granivory and seasonal dietary shifts in desert gerbilline rodents

Association of Host and Microbial Species Diversity across Spatial Scales in Desert Rodent Communities

The role of site, habitat, seasonality and competition in determining the nightly activity patterns of psammophilic gerbils in a centrifugally organized community

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