Thirteen termite mounds and 13 similar-sized control plots were surveyed in central Zimbabwe in order to study large mammalian browsing and vegetation characteristics. The mounds supported almost twice as many tree species as the control plots and the woody vegetation was denser on mounds compared with the woodland plots. Species of woody plants were recorded along with the percentage of branches browsed (cumulative browsing score) by black rhino, Diceros bicornis, elephant, Loxodonta africana and other browsers combined. In addition we measured how the cumulative browsing score on three woody plant species, Acacia nilotica, Colophospermum mopane and Dichrostachys cinerea, which were common both on and off mounds, was related to the distance from mound centre. Both black rhino and elephant cumulative browsing scores were significantly higher on the mound plants compared with the woodland plots. Cumulative browsing score was negatively related to distance from the mound centre for Dichrostachys cinerea, Colophospermum mopane and Acacia nilotica. We propose that termite mound construction in miombo woodland contributes to sustaining populations of megaherbivores and perhaps some woody species in these areas.

Macrotermes mounds are a significant feature of African woodland landscape, contributing to habitat heterogeneity. The mounds are massive, often many centuries old, and support dense vegetation and a suite of woody plant species scarce in surrounding woodland. The present study tested the hypothesis that Zimbabwean Macrotermes mounds, with their greater niche availability, were more heavily utilized by small vertebrates than the surrounding miombo woodland. We carried out a survey of amphibian, reptile and mammal species during early and late rains for 16 termite mounds and 16 adjacent woodland habitat sites, and compared numbers of individuals, species and diversity. For amphibians and reptiles, individual numbers and species did not differ significantly between habitats and their activity was more influenced by season. For mammals, however, significantly more individuals and species were captured on termite mounds, with three species captured only on mounds (most notably the musk shrew Crocidura hirta spp. complex) and all others showing marked preference for this habitat. The greater number of mammals on termite mounds contributed to total small vertebrate biomass being 800 g/ha for termite mounds compared with 380 g/ha in woodland. For mammals certainly, Macrotermes mounds provide significant food and habitat in miombo woodland.

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1. Mixed diets are common in vertebrates, and may be explained by several hypotheses including the availability and nutrient composition of different types of food, the presence of toxins, associative effects in digestion or non‐nutritional factors such as foraging efficiency or predation. This study investigated diet mixing in the omnivorous tortoise Kinixys spekii, which consumes fungi, vascular plants and invertebrates in the field. Tortoises feeding ad libitum on these three diets had a higher intake of digestible energy from fungi than from leaves or millipedes (69, 42 and 31 kJ kg–1 day–1 respectively). 2. Tortoises offered pairwise combinations of foods chose mostly that giving the highest rate of digestible energy intake; 73:27 fungi:leaves, 92:8 fungi:millipedes, and 91:9 leaves:millipedes, by wet mass. Nevertheless, some of the food giving a lower energy intake was eaten. 3. Tortoises feeding ad libitum on a mixed diet (90:10 leaves:millipedes by wet mass) had similar food intake rates and gut retention times to those feeding on leaves. The digestibility of energy was lower for the mixed diet than for diets of leaves or millipedes; a significant negative associative effect. 4. The rate of intake of dry mass did not differ between the three pure diets, the selected diets, or the mixed diet, though this was about 50% higher at 30 °C than outdoors, and represents a limitation due to digestion or appetite. Intake of other foods decreased the intake of dry mass of the preferred food, fungi, by an equal amount. 5. The three foods had similar levels of protein as a proportion of dry mass, partly because of the high ash content of millipedes. The digestibility of protein was higher in millipedes, but the rate of intake of total and of digestible protein was in the same rank order as that of energy (fungi > leaves > millipedes). Although the quantity of protein provided no nutritional explanation for inclusion of lower energy foods in the diet, the quality of protein may differ between food types. 6. Herbivorous tortoises are known to face limitations from calcium and sodium balance. Fungi had a lower level of calcium and a lower ratio of sodium:potassium than leaves; millipedes had values higher than leaves. Foods that are non‐optimal in terms of energy are probably included in the diet for micronutrients such as minerals or essential amino acids.

In arid or semi-arid areas of southern Africa, frogs are typically active nocturnally and seasonally. They may adopt a variety of strategies to conserve water durinli the day or durins: the unfavourable part of the year. Aquatic frogs (e.g. Xenopus, most speciesof RanIJ, PtychmJena and Phrynobatrachus) do not normally have a water conservation problem except when the water in or near which they are living dries up. Burrowing frogs (e.g. Bu/o, Pyxicephalus, Tomoptema and Brel/keps) are able to select microhabitats in the soil which reduce evaporative water loss. Burrowing may, in particular cases, be associated with the formation of a keratinized cocoon of stratum corneum which appears to offer a barrier to outward water movement. In arboreal frogs (Chiromantis xerampelina and Hyperolius spp.) the most interesting adaptations are found. Evidence is given in the case ofHyperolius nasums for low evaporative water losses at the end of the dry season. when the frogs sit exposed to the sun and dry air, in flowers. Durins: the rains when H. 1IQSutus is in breeding aggregation the evaporative water losses are high. Chiromantis xerampelina is uricotelic and resistant to desiccation. The three approaches which anurans have adopted in response to water conservation problems have their correlates in bladder size and function. hormonal regulation of water balance and the extent to which water loss can be tolerated. The potential that the southern African amphibian fauna offers for physiological research is emphasized.

Adult males of Locusta migratoria migratorioides (R. & F.) had an oxygen consumption of 120 mm3 g-1 h-1 at 15°C and 988 mm3 g-1 h-1 at 37°C, although respiratory quotient in fed insects (0.83) did not alter over this temperature range. Starvation or starvation and desiccation reduced the respiratory quotient from 0.83 to 0.77 indicating a shift in metabolism from carbohydrates towards fats. It is shown that the amount of biologically useful energy produced (in the form of ATP) remains the same, and that a shift from carbohydrate to fat metabolism requires the depletion of a smaller weight of food reserve. The shift is counterproductive in terms of metabolic water production, as only 0.28 mg g-1 h-1 water is produced in starved or desiccated locusts compared with 0.35 mg g-1 h-1 in fed animals.

The study was aimed at determining the seasonal abundance of Xenopsylla brasiliensis, an important vector of plague in Zimbabwe, from rodent hosts captured in selected habitat types of two periurban suburbs of Harare, Zimbabwe. The removal-trapping method was used to capture the rodents, from which fleas were collected and identified. Percentage incidence index (PII) and specific flea index (SFI) were calculated for X. brasiliensis in relation to rodent species host. Mastomys natalensis, Rattus rattus, Tatera leucogaster, and Rhabdomys pumilio were the rodent species present in the study areas and all species were infested with X. brasiliensis. PII for T. leucogaster in relation to X. brasiliensis was significantly higher (p < 0.05) compared with that of the other rodent species and T. leucogaster also recorded the highest SFI, whereas R. pumilio recorded the lowest indices. In both formal and informal settlements, the highest PII of X. brasiliensis was attained for M. natalensis, followed by R. rattus. In the cultivated habitat, T. leucogaster recorded the highest indices and R. pumilio the lowest. X. brasiliensis was found to cohabitat with Dinopsyllus lypusus and Ctenophthalmus calceatus on M. natalensis, R. rattus, and T. leucogaster. No cohabitation was recorded for R. pumilio. For all the rodent species captured, both the PII and SFI of X. brasiliensis were highest during the hot-dry season, followed by the hot-wet season, with the cold-dry season recording the lowest indices. The overall cohabitation was highest during the hot-dry season and lowest during the hot-wet season. The findings of the present study fit the reported occurrence of plague outbreaks during the hot-dry season in periurban Zimbabwe.

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