Granivory and Plant Selection by Desert Gerbils of Different Body Size

Kam, Michael; Khokhlova, Irina S.; Degen, A. Allan

doi:10.2307/2265957

Cited by 11 publications

(13 citation statements)

References 9 publications

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“…A foraging decision of an animal about a patch that it will exploit is based not only on the amount of food that it may obtain but also on the efficiency of food acquisition and processing (Brown et al 1994;Kam et al 1997). In particular, the energetic cost of digestion is important, as different types of foods entail different energy costs (Piersma et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Effect of host gender on blood digestion in fleas: mediating role of environment

et al. 2009

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We investigated mechanisms of male-biased parasitism by studying the rate of digestion and survival time after a single blood meal in fleas Xenopsylla ramesis parasitizing males and females of the rodent Meriones crassus. Assuming that male hosts represent better patches for fleas than female hosts, we predicted that fleas (1) will digest blood of a male host faster than blood of a female host and (2) will survive longer after a single blood meal taken from a male host. To understand the possible role of environmental factors in mediation of the relationship between flea performance and host gender, we tested our predictions in male and female fleas under low (75%) and high (95%) relative humidity (RH). Host gender affected duration of digestion only at the middle and late stages of digestion and only interacting with either flea gender or RH or both. At the early stage of digestion, fleas of the same gender at the same RH digested blood at similar rates, independent of host gender. The rate of digestion did not differ between male and female fleas at 75% RH, but the duration of early stage was significantly shorter in female than in male fleas at 95% RH. At the middle stage of digestion, male fleas at both RH digested blood of male and female hosts at similar rates, but at lower RH, female fleas digested blood from male hosts at a significantly faster rate than blood from female hosts. At the late stage of digestion, both male and female fleas digested blood faster from male hosts than from female hosts at 75% RH, but the opposite was true at 95% RH. Survival time of fleas after completion of digestion was affected by RH, being longer at 95%, and flea gender, being longer in females. Fleas fed on female hosts died faster than fleas fed on male hosts, but this was found only at 95% humidity. We concluded that the relationship between flea performance and host gender was mediated by external conditions.

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Section: Discussionmentioning

confidence: 99%

Effect of host gender on blood digestion in fleas: mediating role of environment

et al. 2009

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“…For each experiment, the mean D i s were calculated, and 95% confidence intervals were used to detect whether the mean preference was significantly positive or negative. We used the index D because it met all three criteria for a good index of diet preference proposed by Cock (1978) and is sensitive to small changes in preference (Kam et al, 1997).…”

Section: Consumption Trialsmentioning

confidence: 99%

Role of Volatile and Non-Volatile Plant Secondary Metabolites in Host Tree Selection by Christmas Beetles

2011

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Individual Eucalyptus trees in south-eastern Australia vary considerably in susceptibility to herbivores. On the one hand, studies with insect herbivores have suggested that variation in the concentrations of foliar monoterpenes is related to variation in susceptibility. On the other, studies with marsupial folivores have suggested that variation in the concentrations of sideroxylonals (a group of formylated phloroglucinol compounds) is responsible for variation in susceptibility. We examined relative importance of sideroxylonals and 1,8-cineole (a dominant monoterpene) in host tree selection by Christmas beetles (Anoplognathus species: Coleoptera: Scarabaeidae) by using no-choice experiments, choice/no-choice experiments, and manipulative experiments in which concentrations of sideroxylonals or 1,8-cineole were altered. We used two species of host Eucalyptus, one species of non-host Eucalyptus, and three species of non-host non-Eucalyptus trees. Leaf consumption by Christmas beetles was negatively correlated with the concentrations of sideroxylonals and 1,8-cineole. Artificial increases in the concentration of sideroxylonals or 1,8-cineole reduced leaf consumption by Christmas beetles. An artificial reduction in foliar monoterpenes had no effect on leaf consumption by the beetles when leaves contained high or very low concentrations of sideroxylonals. However, when the concentration of sideroxylonals was moderate, a reduction in the foliar monoterpenes increased leaf consumption by the beetles. Therefore, monoterpenes such as 1,8-cineole may be used as a negative cue by Christmas beetles. The pattern of food consumption on non-host Eucalyptus species and non-host non-Eucalyptus species suggest that both positive and negative cues may be used by Christmas beetles to select host trees.

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“…Only males were used to avoid confounding effects related to female reproductive cycles. Gerbillus dasyurus is primarily granivorous; when seeds are readily available, green vegetation comprises c. 15% of its dietary intake and is used as a source of water (Kam, Khokhlova & Degen, 1997). Animals in the laboratory colony were maintained at 25 8C and a photoperiod of 12 h light and 12 h dark and were fed millet seeds and fresh alfalfa (Medicago sp.)…”

Section: The Hostmentioning

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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Granivory and Plant Selection by Desert Gerbils of Different Body Size

Cited by 11 publications

References 9 publications

Effect of host gender on blood digestion in fleas: mediating role of environment

Effect of host gender on blood digestion in fleas: mediating role of environment

Role of Volatile and Non-Volatile Plant Secondary Metabolites in Host Tree Selection by Christmas Beetles

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

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