Water Intake in Two Coexisting Desert Rodents, Acomys cahirinus and Gerbillus dasyurus

Degen, A. Allan; Kam, Michael

doi:10.2307/1381883

Cited by 8 publications

(5 citation statements)

References 13 publications

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“…Suppression of M. musculus by G. dasyurus seems to be a result of competition for invertebrates as water sources rather than competition for seeds. G. dasyurus can tolerate relatively low amounts of free water in its diet (Degen and Kam 1992), whereas M. musculus has high water requirements (Moro and Bradshaw 1999) and a water deficit can limit its breeding success and population levels (Mutze et al 1991). Our observations on decreased breeding success of M. musculus in the presence of G. dasyurus supports this suggestion.…”

Section: Discussionmentioning

confidence: 99%

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Can interaction coefficients be determined from census data? Testing two estimation methods with Negev Desert rodents

Shenbrot¹,

Krasnov²

2002

Oikos

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Two approaches based on regression models are proposed to estimate competition from census data. The “static” approach is based on censuses of population sizes among species at one point in time over many sites. The “dynamic” approach relies on a time series of species abundance data to examine whether per capita changes in one species are associated with the abundance of other species. We estimated competition interactions in a Negev rodent community consisting of 10 species using both approaches, basing on 8 years (16 half‐year periods) of observations. The static approach revealed significant competitive interactions in four of 45 pairs of species, whereas the dynamic approach did so in the same four plus two more pairs. For each species pair, both approaches revealed significant negative interactions in only 1–4 of 16 seasons. The static approach provided nearly symmetric estimations of competition, whereas estimations of dynamic approach were asymmetric. Moreover, estimations of the two approaches did not coincide in time. Cases of negative interactions recorded by the static approach were more frequent at peak and increase phases of population density dynamics, whereas those recorded by the dynamic approach were more frequent at peak and decline phases. Results of field removal experiments with Mus musculus and Gerbillus dasyurus supported predictions of dynamic but not static approaches. We hypothesized that in harsh and fluctuating desert environments that disrupt equilibrium, the dynamic approach indicates true (exploitation) competition, whereas the static approach reflects negative interspecific spatial association (interference).

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Section: Discussionmentioning

confidence: 99%

“…G. gerbillus and G. henleyi are strictly granivorous (Qumsiyeh 1996, Kam et al 1997). G. dasyurus feeds mainly on seeds with some invertebrates (Degen and Kam 1992, Qumsiyeh 1996). The diet of Meriones crassus includes seeds, green plant parts and insects (Harrison and Bates 1991, Kam et al 1997).…”

Section: Discussionmentioning

confidence: 99%

Can interaction coefficients be determined from census data? Testing two estimation methods with Negev Desert rodents

Shenbrot¹,

Krasnov²

2002

Oikos

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“…Energy requirements for maintenance of each of the 9 G. dasyurus was calculated as 6.74 m b 70.54 kJ day 71 (Degen & Kam, 1992). We used the metabolic mass of g 70.54 to compensate for different body masses (French et al, 1976;Degen, 1997).…”

Section: Experimental Designmentioning

confidence: 99%

“…Energy intake was calculated as described by Degen & Kam (1992). Gross energy of each of the items eaten (seeds, husks, leaves) and of faeces was measured with a ballistic bomb calorimeter (Gallenkamp, Model CBB-370).…”

Section: Food and Energy Intakementioning

confidence: 99%

Energy cost of ectoparasitism: the fleaXenopsylla ramesison the desert gerbilGerbillus dasyurus

et al. 2002

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Metabolizable energy intake and changes in body mass was measured in the desert gerbil Gerbillus dasyurus when parasitized by the¯ea Xenopsylla ramesis. We hypothesized that energy requirements for maintenance, or average daily metabolic rate, of parasitized gerbils would be higher than those of nonparasitized gerbils. We also hypothesized that the ef®ciency of utilization of energy for maintenance would be the same for parasitized and non-parasitized gerbils, as this measurement is dependent mainly on dietary quality. Fifty¯eas feeding on a gerbil consumed 3.68 1.19 mg blood, in total. This amounted to 34.3 1.8% of body mass of a starving¯ea and only about 0.17% of the blood volume of the host. The absolute amount of blood consumed by X. ramesis is the lowest reported for¯eas in other studies. This suggested that the pressure of parasitism of X. ramesis on G. dasyurus in terms of blood consumed was relatively low. Both our hypotheses were con®rmed. Average daily metabolic rate of the parasitized gerbils (7.75 kJ g 70.54 d 71 ) was 16% higher than that of non-parasitized gerbils (6.69 kJ g 70.54 d 71 ). In addition, at zero metabolizable energy intake, the parasitized gerbils lost body mass at a faster rate than the nonparasitized gerbils (4.34 vs 3.95% body mass d 71 ). The ef®ciency of utilization of energy in the parasitized and non-parasitized gerbils was similar.

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“…190n, Bureau of Analysed Samples Ltd, Bristol, UK) as standard. Dry matter intake of each food item was calculated as the difference between dry matter offered and dry matter of the remains (Degen and Kam, 1992). Gross energy intake was calculated from the intake of each item and its calorific value, digestible energy intake was calculated as the difference between gross energy intake and faecal energy output, and metabolizable energy intake was assumed to be 98% of digestible energy intake (Grodziski and Wunder, 1975;Khokhlova et al, 2002).…”

Section: Laboratory Measurementsmentioning

confidence: 99%

Flea infestation does not cause a long-term increase in energy metabolism in Gerbillus nanus

Kam

Khokhlova

Krasnov

et al. 2011

Journal of Experimental Biology

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SUMMARYFleas can increase the metabolic rate of their hosts. It has been suggested that a constitutive response, in which the host constantly maintains a relatively high level of energy metabolism to combat the parasite, is advantageous for hosts with high parasite infestation, while an induced response, in which the host increases energy metabolism in response to a parasite attack, is advantageous with low parasite infestation. As free-living Gerbillus nanus show a relatively low flea infestation, we hypothesized that this host uses an induced strategy and, consequently, flea infestation would not impose a long-term effect on energy metabolism. In a previous study in spring, higher field metabolic rate (FMR) was found in free-living parasitized than in non-parasitized G. nanus. In this study, G. nanus were captured at Hazeva in spring; some had fleas (N14) and some did not (N10). We brought them to the laboratory, removed the fleas from those that were infested and, after 3weeks, measured average daily metabolic rate (ADMR) of all rodents. ADMR averaged 8.68±0.95kJg -0.54 day -1 for all rodents and was similar between previously parasitized and non-parasitized G. nanus while free living. Thus, the hypothesis that flea infestation does not have a long-term effect on energy metabolism was supported, as was the idea of an induced over a constitutive immune response by G. nanus in combating parasites.

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Water Intake in Two Coexisting Desert Rodents, Acomys cahirinus and Gerbillus dasyurus

Cited by 8 publications

References 13 publications

Can interaction coefficients be determined from census data? Testing two estimation methods with Negev Desert rodents

Can interaction coefficients be determined from census data? Testing two estimation methods with Negev Desert rodents

Energy cost of ectoparasitism: the fleaXenopsylla ramesison the desert gerbilGerbillus dasyurus

Flea infestation does not cause a long-term increase in energy metabolism in Gerbillus nanus

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