Ecological observations on epomorphorine fruit-bats (Megachiroptera) in West African savanna woodland

Three species of Megachiroptera were studied in Mole National Park, Ghana, by systematic netting in various habitats and by observations of bats in the field and in captivity. This study, undertaken in July-August 1974 and 1975, is a preliminary attempt to elucidate how these species partition the resources available to them, with particular emphasis upon roosting habits, food resources, and temporal and spatial differences in foraging behaviour. All three species give birth towards the beginning of the wet season and are probably polyoestrus. The larger species, Epomophorus gambianus , does not appear to compete with the other two due to differences in roosting habits and the food resources available to it consequent upon its larger size. The two smaller species, Micropteropus pusillus and Nanonycteris veldkampi , are similar in size. N. veldkampi is presumed absent from Mole in the dry season when food is scarce; in the wet season it may minimise competition by being better adapted for nectarivory, foraging later, and foraging at a greater height than M. pusillus.     

Habitat preferences of ungulates in closed savanna of central Africa

Habitat preferences of fifteen species of ungulate were studied between July and September 1975 in dry savanna woodland of Mwabvi Game Reserve, Southern Malawi, Central Africa. Thirteen vegetation types were recognized using vegetation transects and plotless sampling techniques (but three of these are omitted from further analysis here either because of the difficulty of sampling in a representative manner or because of their infrequency). A combination of six methods was used to study habitat preferences since each had particular advantages or disadvantages, although quadrat sampling of fresh pellets/spoor counts was the most satisfactory and so used predominantly. The most common and widely distributed species was the Greater kudu, although abundance estimates in different habitats varied according to the method used. Pellet/spoor counts showed heavy use of open grassland by kudu which was not detected by daytime drives. Temporal patterns of activity indicated that the species was moving into more closed woodland during the day and only coming out into open grassland at night. Relative abundance estimates of a species may also be affected by changing group size. The mean group size of kudu increased in more open vegetation, although group size in warthog did not show this relationship. Some species, e.g. impala, reedbuck, and klipspringer showed narrow habitat preferences, occurring in only one or a few vegetation types, whilst others, e.g. kudu, sable, duiker, suni, and grysbok showed much broader preferences. Mixed Colophospermum mopane /Acacia woodland had the highest species diversity but rather low abundance. Open grassland and Acacia/Albizia woodland had high species diversity together with the greatest abundance of ungulates. Open Julbernardia/Diplorynchus, Brachystegia/Julber-nardia woodland, and particularly Pterocarpus/Diplorynchus/Combretum hill woodland had the lowest species diversity and abundance of ungulates. Ready access to cover and availability of suitable food plants probably account for the preferences of certain vegetation types over others, whilst the different behavioural ecology and food preferences of each species account for individual species differences. Access to water probably also determines habitat preferences in particular species, and studies during the wet season may show different distributions.     

池养大口胭脂鱼鱼种的食性

池养大口胭脂鱼鱼种的食性研究表明 ,大口胭脂鱼鱼种为浮游动物尺寸选择性鱼类 ,其选食行为主要受鱼体及水体中浮游动物的个体大小影响 ,与浮游动物的种类、逃跑能力、运动方式等关系不明显。并初步探讨了 3种浮游生物食性鱼类 (大口胭脂鱼、鲢、鳙 )的食物关系。     

Feeding habits of the spotted hyaena in the Niokolo Koba National Park, Senegal

The food habits of the spotted hyaena were studied during the dry season in relation to food availability in the Niokolo Koba National Park, Senegal. Frequency of occurrence of the different foods was quantified by means of scat analysis; species occurrence in the diet was compared with availability in the study area. Large and medium-sized mammals, such as the buffalo, the hartebeest and the warthog, were eaten more often than expected.     

Size of prey ingested by whitefish,Coregonus sp., larvae. Are Coregonus larvae gape-limited predators?

The feeding ecology of whitefish, Coregonus , larvae in oligotrophic Lake Sarnen and eutrophic Lake Hallwil is presented, taking into consideration the size of the prey ingested in relation to the mouth size of larvae and to the availability of zooplankton.
When larvae grow from 10 to 16 mm their mouth width increases from 500 to 1000 μm while their gape height, with the mouth open at 45 and 90°, increases from 200 to 400 μm and from 400 to 700 μm, respectively, whichever lake is considered.
The differences found in the mean prey width between the two lakes arise in part from the composition of diets, and in part from differences in size of the available prey organisms. Whatever the origin of the larvae and the taxon we consider, larvae seem to ingest the most abundant prey size without selecting the biggest ones available even if, from a mechanical point of view, they would be able to ingest them.
Taking into account the generally low density of zooplankton in the uppermost layer of the lake, we conclude that whitefish larvae eat in the manner such as to decrease the cost of prey capture, in terms of energy and time, by choosing the more abundant prey available.     

Ranging behaviour and activity of red foxes (Vulpes vulpes: Mammalia) in relation to environmental variables, in a Mediterranean mixed pinewood

The relationships between the main abiotic environmental variables, food availability, dict, activity and home range size of the fox in a Mediterranean mixed pinewood were assessed. Food habits were determined by faecal analysis on a weekly basis. Food availability was measured by weekly censuses. Radio-tracking allowed the detection of fox movements and activity. Individual differences shown by a sample of four radio-tagged foxes were analysed. Juniper berries (Juniperus oxycedrus) were the staple of the diet during the year, except in summer. Insects, mainly nocturnal Orthoptera and cicada larvae (Cicada orni), were the main prey in the warm season. Large vertebrates, mostly wild boars (Sus scrofa), were scavenged in winter. In the warm season foxes' activity depended largely on the pattern of activity of prey. Food habits tended to depend on food availability, which, in turn was mainly influenced by temperature. In spite of habitat similarity, individual differences in food habits were detected within the same season. Home ranges were larger in pinewood than in neighbouring heterogeneous habitats. Individual home range sizes were: (i) directly correlated to Orthoptera abundance and distribution; (ii) inversely correlated to the abundance of cicada larvae in diet. Resident males may exist in fox society, exploiting other males' territories when good clumped food resources are available.     

The activity budgets and activity patterns of sympatric grey rhebok and mountain reedbuck in a highveld grassland area of South Africa

Behavioural observations were carried out on grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve, South Africa, for a period of 1 year between May 2001 and April 2002. Four harem herds of grey rhebok, five territorial male mountain reedbuck and female mountain reedbuck (herds grouped as one individual) were monitored to determine activity budgets and activity patterns. Both species spent more time feeding in the late afternoon during relatively cool temperatures, and more time resting in the middle of the day during relatively high temperatures. Statistical comparisons between the two species of the percentage time feeding and resting found no differences between them, although mountain reedbuck spent more time resting overall than grey rhebok. Both species were active at night.     

On the food of the freshwater eels and their feeding relationship with the salmonids

Following the results of the cursory investigations made by Jones & Evans (1960,1962) into the predatory habits of eels we decided to enlarge on this work. Consequently we looked at the stomach contents of about 5000 eels. In addition and at the same time two Welsh streams carrying salmonids were selected and sampled specifically to try to determine the relationship in the feeding habits of eels and salmonids.
The food of eels consisted mainly of trichopteran and dipteran larvae and plecopteran and ephemeropteran nymphs, though at times Gastropoda, Annelida, Crustacea and fish were common in the stomachs. Fish was not an important dietary item but, when eaten, the fish most commonly taken were elvers and eels.
In the River Dwyfach the salmonids ate more or less the same type of food as the eels, but the trout ate more surface food than the young salmon.
The similarity in feeding between the eels and salmonids resulted in apparent competition during the warmer months. In winter when the eels ate little the competition was thus almost negligible. Even though we speak of competition for the food available in the summer months we feel that before this can be accepted as fact we must know the relative abundance of each food organism eaten at this time.     

Resource partitioning along multiple niche dimensions in differently sized African savanna grazers

Resource partitioning among mammalian savanna herbivores is thought to be predominantly driven by differences in body size. In general, large herbivore species utilize abundant low quality forage while small herbivores focus on scarcer high quality food items. However, in a natural system other factors such as digestive strategy, season and the presence of megaherbivores (body size > 1000 kg) are likely to complicate allometric predictions. Non‐ruminants are probably better able to cope with abundant low quality food than ruminants of the same size causing a non‐ruminant to act ‘larger’ than allometrically predicted. Also, the effect of alternating seasons with high and low food availability on diet choice and hence the competitive interactions between co‐occurring herbivores is still poorly understood. Lastly, how megaherbivores deviate from allometric predictions (based on smaller species) is still not well quantified. In this study we examine resource partitioning among three ruminant and three non‐ruminant grazers: impala, wildebeest, buffalo, warthog, zebra and white rhinoceros (megaherbivore) in the savanna of Hluhluwe iMfolozi Park, South Africa. We analysed habitat and diet overlap, specifically grass species (something not commonly investigated) and grass height eaten, in both the wet and the dry seasons. We found that habitat utilization differences among the species were generally small and did not vary between seasons. Diets within feeding patches overlapped during the wet season but highly diverged during the dry season. Body mass differences among species explained their dry season resource partitioning for all species except for comparisons with the megaherbivore (white rhino), while differences in digestive strategy were not related to niche overlap in either season. We conclude that savanna herbivores in this system coexist mostly through body size‐driven resource partitioning in the dry‐season, with the exception of the white rhino (megaherbivore).     

Black-backed jackal diet at Mokolodi Nature Reserve, Botswana

We examined the feeding habits of black‐backed jackals at Mokolodi Nature Reserve, Botswana, by analysing 237 scats collected between November 1995 and February 1997. Jackal dietary habits reflected the availability of a wide variety of food items and the differential vulnerability of prey. Potential animal and plant food available to jackals varies throughout the year because of its seasonal character. Seasonality of prey occurrence in scats was pronounced for small mammals, miscellaneous fruits and invertebrates. Across all seasons, mammals were the most common food resource (32.4%, n = 168), followed by anthropogenic items (14.8%), fruits (12.9%), invertebrates (10.8%), birds (8.5%), unidentified items (3.5%) and reptiles (1.4%). The presence of domestic mammals and poultry remains in scats reveals their importance in the diet of jackals and the tendency of jackals to frequent human settlements in search of food. Some ecological implications of jackal dietary habits are also explored.     

Maternal and infant demographics and health status: a comparison of black, Caucasian, and Hispanic families

The relationships among ethnicity, demographics, smoking and drinking habits, and maternal and infant health were examined in a sample of 171 low-income and low-risk Black, Caucasian, and Hispanic families. Few ethnic differences in the health status of the mothers and their infants emerged when ethnic differences were directly examined; however, a latent variable analysis indicated that ethnicity was related to smoking and drinking habits such that Caucasian mothers were more likely to smoke and drink. Smoking and drinking, in turn, led to smaller infant size at birth. Demographic differences found in level of income, education, and family composition suggest that low-income families are not necessarily homogeneous.     

Chromosomes of the antelope genus Kobus (Artiodactyla, Bovidae): karyotypic divergence by centric fusion rearrangements

G- and C-banded karyotypes of four species of the genus Kobus were compared using the standard karyotype of Bos taurus. Chromosomal complements were 2n = 50-54 in K. ellipsiprymnus, 2n = 50 in K. kob, 2n = 48 in K. leche, and 2n = 52 in K. megaceros. The number of autosomal arms in all karyotypes was 58. Fifteen autosomal pairs were conserved among these four species, including the 1;19 and 2;25 centric fusions, and autosomal differences involved eight centric fusion rearrangements. Five centric fusions were each unique to a particular taxon: 3;10 (K. leche), 3;11 and 6;29 (K. kob), and 5;17 and 7;11 (K. ellipsiprymnus). The 4;7 fusion occurred in K. leche and K. megaceros, whereas the 5;13 fusion occurred in K. kob and K. leche; the 6;18 fusion was found in three species but was absent in K. kob. Differences between the X chromosomes of the four Kobus species were attributed to heterochromatic additions or deletions, and Y-chromosome differences may have been the result of pericentric inversion. G-banded karyotypes of putative K. l. leche and K. l. kafuensis appeared identical, as did C-banded karyotypes of the two subspecies. Karyotypes of K. e. ellipsiprymnus and K. e. defassa differed as a result of the 6;18 centric fusion, which was polymorphic in K. e. defassa, and the 7;11 centric fusion, which was polymorphic in K. e. ellipsiprymnus but absent in K. e. defassa. Several centric fusions were related by monobrachial chain-IV complexes; however, records of hybridization indicate that reproductive isolation between at least certain species of Kobus is incomplete. Karyotypic differences between K. ellipsiprymnus (including K. e. ellipsiprymnus and K. e. defassa), K. kob, K. leche, and K. megaceros support the validity of these taxa, as well as the need to manage them as separate populations.     

Helminths in sympatric populations of mountain reedbuck (Redunca fulvorufula) and gray rhebok (Pelea capreolus) in South Africa

Helminths of mountain reedbuck (Redunca fulvorufula fulvorufula) and gray rhebok (Pelea capreolus) were investigated in South Africa between June 1999 and February 2002. Forty-one mountain reedbuck were culled at Sterkfontein Dam Nature Reserve over 8 different periods, and 25 mountain reedbuck were culled at Tussen die Riviere Nature Reserve over 3 different periods. A total of 17 kinds of helminths were found at the 2 sites, including 15 nematodes, 1 trematode, and 1 cestode. At Sterkfontein, the most prevalent and abundant species were Cooperia yoshidai, Longistrongylus schrenki, and Haemonchus contortus, with the latter 2 being more abundant during November/December than at other times of the year, probably because infective larvae increased on pasture at that time. No statistical differences were found in parasite loads between male and female mountain reedbuck. No correlation was found between fecal egg counts and adult worm counts or between parasite counts and body condition. At Tussen die Riviere, helminths in mountain reedbuck were less prevalent and abundant than at Sterkfontein. The most important species were Nematodirus spathiger, Trichostrongylus falculatus, and Cooperia rotundispiculum. Four gray rhebok died of natural causes at Sterkfontein, from which 5 kinds of helminths were recovered, including C. yoshidai and Paracooperioides peleae.     

The foraging ecology of two pairs of congeneric demersal fish species: importance of morphological characteristics in prey selection

The feeding habits of two sympatric species pairs of demersal fish ( Mullus barbatus-Mullus surmuletus, Serranus cabrilla-Serranus hepatus ) which occupy the shallow coastal area (25–30 m) in Iraklion Bay were investigated from samples collected on a monthly basis (August 1990 to August 1992). Stomach content analyses revealed that all of them were carnivores, feeding mainly on benthic invertebrates, and that each species consumed a narrow range of prey species with no significant dietary overlap. The morphology of their feeding apparatus was compared to examine the effect of any morphological differences on food selection and resource partitioning between the fish species. The species could be distinguished on the basis of the size of their mouth gape, the number of gill rakers and the length of their intestine. This study shows that each species pair follows a different strategy segregating along food niche dimensions. In particular, M. barbatus and M. surmuletus segregate their feeding niche consuming different prey taxa with similar sizes whereas S. cabrilla and S. hepatus differ considerably with respect to the degree to which prey species contribute to their diets coupled with differences in mean prey sizes.     

Feeding habits and seasonal trophic guilds structuring fish community in the bay mouth region of a tropical estuarine habitat

Understanding trophic relationships of fish in estuarine ecosystem is an important element for sustainable resource management. This study examined the feeding habits of 29 dominant fish species, characterized the trophic guilds, assessed the impact of season and clarified the role of diets in structuring the fish community in the mouth region of Pattani Bay, Thailand. Samples of 5792 fishes collected monthly by gillnets from March 2019 to February 2020 were used for stomach content analyses. It was found that the number of food types and fullness index differed between fish taxa (P < 0.001). Most fishes were specialist feeders feeding on specific food components and were categorized into five trophic guilds: piscivore, shrimp-fish feeder, polychaete feeder, zooplanktivore and planktivore. Six species were piscivorous, considered as apex predators, that fed almost entirely on fishes. High diet overlaps among some species (>0.6) were recorded. Not much variation in seasonal guilds was observed: four guilds in the dry season, three in the moderate rainy season and four in the rainy season. Some species remained in the same guild the whole year round, but some fishes changed seasonally. Two fish communities from different regions of the bay were segregated based on feeding habits. The inner bay community comprised mainly copepod and plankton feeders, but there were more piscivores in the deeper bay mouth area. Results from this study help us to understand the feeding habits and trophic guilds of dominant fish species at the mouth of this tropical estuarine bay.     

Grazing lawns contribute to the subsistence of mesoherbivores on dystrophic savannas

Resource manipulation, such as the creation and maintenance of grazing lawns, may shape the structure of herbivore communities. We tested the hypothesis that grazing lawns contribute towards the subsistence of the Kobus kob kob in a dystrophic West African savanna, where kob and Hippopotamus amphibius both occur. Comparison of the foliage of grazing lawns and ungrazed swards shows that hippo lawns are more nutritious with regard to both structure and nutrients; kob lawns are higher in nutrients only. Up to the early dry season, hippo lawns meet kob energy and protein demand, thereafter, the shortness of the sward limits intake. Kob lawns always provide sub-maintenance values. Grazing on ungrazed swards is least profitable. We suggest that grazing lawns are essential for the daily subsistence of mesoherbivores, particularly on nutrient-poor soil, and that megaherbivores facilitate their food supply, for at least part of the year.     

Use of habitat resources by scarab dung beetles in an savanna

In the Queen Elizabeth National Park, Uganda, we compared the scarab beetle assemblages in the dung of three wild ungulates (African buffalo, a ruminant foregut fermenter; hippopotamus, nonruminant foregut fermenter; and warthog, nonruminant hindgut fermenter). Dung was collected from two sandy-clay soils with different percentage of coarse sand. We aimed at investigating habitat resource selection by dung beetle species within a savanna natural contest with abundant and diverse food availability. Analyses were performed to detect differences for dung beetle assemblages in abundance, diversity, functional groups. Species richness in the three dung types and in the two soil types was similar. However, warthog dung and sandy-rich soil appeared the preferred habitat resources, in terms of abundance and biomass, while hippopotamus dung hosted the lowest values for these parameters. The analysis of functional groups revealed that slow-burying tunnellers held the major role, both in terms of abundance and biomass, and were mainly found in warthog dung.     

Approach to the alimentary patterns of a ample group of Madrid's Gypsy Community

The gypsy community in Spain has been widely studied from cultural, social and historical viewpoints. Mesa's (1981) work stands out as an example of a biological anthropological perspective; however, this study did not analyse the links between this people's culture and their biological characteristics. The current study examines one of these cultural factors, with a nutritional investigation of a sample group of Madrid's gypsy community and subsequent analysis of their alimentary patterns. We studied a sample from a settlement in the northern suburbs of Madrid. The content and frequency of each of the food products consumed by the families was determined over four weekdays and one day at theweekend. To evaluate behavioural variation among the sampled families, subgroups were defined by categories of sex, age group, family status and socioeconomic level. Overall nutritional patterns were described and then examined further by multivariate analyses. We conclude that a lack of information and the impact of acculturation have resulted in the inappropriate choice of available foodstuffs and consequent malnutrition. Despite the apparent homogeneity of this community, discriminant analysis revealed significant differences in eating habits between socioeconomic levels. This kind of study is important as it allows the problem of improving the health and living conditions of these people to be tackled with greater efficiency and precision.     

Modelling ungulate dependence on higher quality forage under large trees in African savannahs

In African savannahs, large trees improve grass quality, particularly in dry and nutrient poor areas. Enhanced below-canopy grass nutrients, such as nitrogen and phosphorus contents should therefore attract and benefit grazers. To predict whether ungulates really need these forage quality islands we focused on four grazer species, i.e., zebra, buffalo, wildebeest, and warthog, differing in body size and digestive system. We confronted literature estimations of their feeding requirements with forage availability and quality, observed in three South African savannah systems, through linear modelling. The model predicted the proportion of below-canopy grass that grazers should include in their diet to meet their nutritional requirements.During the wet season, the model predicted that all animals could satisfy their daily nutrient requirements when feeding on a combination of below- and outside-canopy grasses. However, wildebeest, having relatively high nutrient demands, could meet their nutrient requirements only by feeding almost exclusively below canopies.During the dry season, all animals could gain almost twice as much digestible protein when feeding on below – compared to outside-canopy forage. Nonetheless, only warthogs could satisfy their nutrient requirements – when feeding almost exclusively on below-canopy grasses. The other ungulate species could not meet their phosphorus demands by feeding at either site without exceeding their maximum fibre intake, indicating the unfavourable conditions during the dry season.We conclude that grazing ungulates, particularly warthog, zebra, and buffalo, actually depend on the available below-canopy grass resources. Our model therefore helps to quantify the importance of higher quality forage patches beneath savannah trees. The composition of grazer communities depending on below-canopy grasses can be anticipated if grazer food requirements and the abundance of large trees in savannahs are known. The model suggests that the conservation of large single-standing trees in savannahs is crucial for maintenance of locally grazing herbivores.     

Uganda kob prefer high-visibility leks and territories

In lekking species, where males provide estrous females withlittle more than sperm, it has been widely supposed that theonly possible benefits to females of mate choice are genetic.We studied female choice of leks and territories in a reduncineantelope, the Uganda kob (Kobus kob thomasi), and found thatfemales consistently preferred high-visibility mating sites.Leks were elevated and had shorter grass and fewer thicketsthan the surrounding areas. Changes in the number of male andfemale kob on 10 leks were correlated with changes in surroundinggrass height, and both females and males preferred leks withexperimentally reduced grass height over neighboring controls.Within a lek, territory popularity was the primary determinantof male daily mating success, and females preferred territoriesrelatively far from thickets, but removal of thickets did notaffect female territory preferences. Because lion hunting successon kob increases with grass height and thicket density, femalesmay benefit directly from these preferences by reducing therisk of predation.