Diet and Prey Selection of Dholes in Evergreen and Deciduous Forests of Southeast Asia

Endangered dholes (Cuon alpinus) are restricted to small and declining populations in Southeast Asia, and little is known about how their ecology differs within the region. We used DNA-confirmed scats and prey surveys to determine the seasonal diet and prey selection of dholes in 2 different landscapes that dominate Southeast Asia: closed evergreen forests in hilly terrain in northern Laos, and open deciduous forests in relatively flat terrain in eastern Cambodia. On both sites, muntjac (Muntiacus spp.; 20–28 kg) was the dominant prey item and was selectively consumed over other ungulates in all seasons. Our findings differ from previous conclusions, based largely on studies from India, that the preferred prey weight range of dholes was either 40–60 kg or 130–190 kg. Other important prey were sambar (Rusa unicolor) in Laos, and wild pig (Sus scrofa) and banteng (Bos javanicus) in Cambodia. Seasonal differences in overall diet occurred in Laos, but not Cambodia, primarily because of an increase in livestock consumption. The mean number of dhole scats in group defecation sites was higher in Cambodia (5.9 ± 0.5 [SE]) than Laos (2.4 ± 0.2), suggesting pack sizes were larger in Cambodia. Our results suggest that regardless of land cover type, prey diversity, or pack size, the management of muntjac will be important for conserving dhole populations in Southeast Asia. In Laos, we recommend that local villagers remove livestock from the protected area during the hot-dry season to reduce livestock predation by dholes. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

Ectoparasites of the swift fox in northwestern Texas

Ectoparasites were collected from chemically immobilized swift foxes (Vulpes velox) in the Texas Panhandle (USA). Three species of fleas (Pulex irritans, Dactylopsylla percernis, and Euhoplopsyllus affinis) and one species of tick (Ixodes sculptus) were found. Pulex irritans was the only abundant ectoparasite; it occurred on all 23 foxes brushed in 1999-2000 and all but one of 34 hosts examined in 2000-01. Otherwise, this swift fox population had a depauperate ectoparasite fauna; the remainder of the ectoparasites only occurred on a few (< or =5%) of the hosts. Because of previous taxonomic confusion between P. irritans and the closely related P. simulans, the zoogeographic distribution of these two species in many areas of western North America needs to be verified. Apparently, only the human flea P. irritans occurs on wild canids in the Texas Panhandle. However, there are previous records of P. simulans on other carnivores in western and central Texas. Some of these specimens were reexamined, and their identifications were reconfirmed. Also, the recent literature on the controversial taxonomic status of these two flea species is reviewed. The male terminal aedeagal sexual apparatus is the only means currently available to separate P. irritans and P. simulans.     

Faecal pellet group counting as a promising method of wild boar population density estimation

The wild boar is a native animal species of the Czech Republic that has significantly increased its population density in recent years. Objective methods of population density estimation are required to inform the intensity of regulation needed for the sustainable management of the wild boar. Population estimation and regulation of the abundance of the wild boar are problematic in comparison to those of other ungulates, and the only widely used method of control is intensive hunting. The purpose of this study was to test if faecal pellet group (FPG) counting was a reliable method of wild boar population censusing in a forest environment. The density of wild boars was evaluated in an area of 22.56 km², circumscribed by both natural and man-made barriers that restrict wild boar migration. As it is essential for proper application of FPG count methods, a separate trial was carried out to determine the daily defecation rate of wild boars. The distribution of faeces in different types of habitat in a forest environment was tested. As the period of faeces accumulation fell within the intensive hunting season, the result is biased by the fact that the calculation includes FPGs produced by animals removed from the population through hunting during winter. The average daily defecation rate of adults and piglets was 4.29 and 5.82, respectively. The corrected (without shot animals) average density of wild boars in the study area estimated by the FPG count at the time of the census was 6.08 individuals (ind.)/km². We have confirmed that an FPG count conducted in winter is applicable for estimation of wild boar abundance on a forested area.     

The bat-eared fox: A dietary specialist?

We studied the degree of dietary specialisation of bat-eared foxes (Otocyon megalotis) by analysing 177 scats collected on a game ranch in central South Africa. Bat-eared foxes generally are considered to be insectivorous with a distinct specialisation on termites, however, our results indicated a much broader and opportunistic diet. Termites were detected in more than 90% of the scats throughout the year, but they only contributed 12–40% to the ingested biomass across seasons. Instead, fruits, primarily bluebush (Diospyros lycioides), were the most important food category in summer (63% biomass) as well as in autumn (74% biomass). Also, high niche breadth values (B = 5.7–6.9 for frequency of occurrence, B = 1.8–4.1 for biomass data) indicated a rather generalistic feeding behaviour. We also documented numerous cases of opportunistic scavenging on carcasses by bat-eared foxes. The difference with earlier dietary studies of bat-eared foxes might be attributable to geographical and ecological variations among sites and also partly to methodological differences. Concerning the latter, no previous studies considered biomass calculations but instead most assessed the frequency of occurrence of prey items, which likely overestimated the importance of small prey such as termites.     

Hyalomma aegyptium as dominant tick in tortoises of the genus Testudo in Balkan countries, with notes on its host preferences

Collection of 1327 ticks sampled throughout Greece, Bulgaria, Romania and Croatia, from 211 tortoises belonging to three species, Testudo marginata Schoepff, T. graeca Linnaeus, and T. hermanni Gmelin, revealed the presence of four species of ixodid ticks, namely Hyalomma aegyptium (Linnaeus), Haemaphysalis sulcata Canestrini and Fanzago, H. inermis Birula and Rhipicephalus sanguineus (Latreille). Study confirmed the strong dominance of all life stages of H. aegyptium among ticks parasitizing west Palaearctic tortoises of genus Testudo Linnaeus. Furthermore, a considerable portion of ticks collected from tortoises in southwestern Bulgaria represent larvae and nymphs of H. sulcata. At the same area we collected as exception one larva and one nymph of H. inermis from a single specimen of T. hermanni. Our findings of four adults of R. sanguineus is the first record of this species from reptilian host. According to our results achieved on localities with syntopic occurrence of two tortoise species, T. marginata and T. graeca represent in the Balkans the principal hosts of H. aegyptium, whereas T. hermanni serves only as an alternative host in the areas close to range of either T. marginata or T. graeca.     

Effects of diet and temperature on condition, proximate composition and three major macro elements, Ca, P and Mg, in barbel Barbus barbus juveniles

Six feeding groups of 60 early juveniles (0.6?g) of a rheophilic cyprinid barbel Barbus barbus were reared in triplicate in 18?glass aquaria. Fish fed a commercial formulated dry diet Aller Futura were compared with those on natural food??commercially available frozen Chironomidae larvae at 17, 21 and 25°C. Daily food rations were adjusted according to fish biomass, differences in hydration between the two diets, and rearing temperature. No mortality occurred during experiment. Temperature, and especially diet, both affected whole body proximate and mineral composition of B. barbus juveniles. Under conditions of this experiment the formulated diet Aller Futura seems to satisfy the demands for calcium and magnesium, while an elevated lipid content in this diet was found and marginally deficient phosphorus content can be concluded. These resulted in a depressed content of phosphorus and total minerals in the body, and in elevated lipid content and condition coefficient in the Futura-fed fish, but no visible body deformities occurred. Advantages and limitations of the condition coefficient K were discussed. This is a non-destructive, express indicator that can be used as a supplementary tool for estimation of changes in body proximate composition in fish juveniles of similar size within a population.     

Life cycle of tortoise tick <Emphasis Type="Italic">Hyalomma aegyptium</Emphasis> under laboratory conditions

The tortoise tick Hyalomma aegyptium has a typical three-host life-cycle. Whereas its larvae and nymphs are less host-specific feeding on a variety of tetrapods, tortoises of the genus Testudo are principal hosts of adults. Ticks retained this trait also in our study under laboratory conditions, while adults were reluctant to feed on mammalian hosts. Combination of feeding larvae and nymphs on guinea pigs and feeding of adults on Testudo marginata tortoises provided the best results. Feeding period of females was on average 25 days (range 17–44), whereas males remain after female engorgement on tortoise host. Female pre-oviposition period was 14 days (3–31), followed by 24 days of oviposition (18–29). Pre-eclosion and eclosion, both together, takes 31 days (21–43). Larvae fed 5 days (3–9), then molted to nymphs after 17 days (12–23). Feeding period of nymphs lasted 7 days (5–10), engorged nymphs molted to adults after 24 days (19–26). Sex ratio of laboratory hatched H. aegyptium was nearly equal (1:1.09). The average weight of engorged female was 0.95 (0.72–1.12) g. The average number of laid eggs was 6,900 (6,524–7,532) per female, it was significantly correlated with weight of engorged female. Only 2.8% of engorged larvae and 1.8% of engorged nymphs remained un-molted and died. Despite the use of natural host species, feeding success of females reached only 45%. The whole life-cycle was completed within 147 days (98–215).     

Developmental response of carp,Cyprinus carpio,larvae fed different foods or starved

Synopsis The developmental interval, body length, dry and wet weight were determined in carp larvae during the first 2 weeks of exogenous feeding. Six feeding groups were reared at 26°C; four groups received different artificial diets, whereas zooplankton-fed larvae and unfed larvae served as controls. It was found that larval developmental rate can be modified by the type of food. The diet affects the relationship between developmental step and weight. The effect of diet on the relationship between development and length becomes manifest at older steps (after longer feeding the same diet). A threshold point, after which satisfactory results of feeding artificial diets to carp larvae can be expected, depends not only on body size but also on the degree of development.     

Comparative analysis of reproductive traits in 65 freshwater fish species: application to the domestication of new fish species

Based on an extensive literature search (1,000 references), the objectives of the present study were to establish a numerical clustering of temperate freshwater fish based on their reproductive traits and to evaluate whether it was possible to extrapolate zootechnical knowledge among species belonging to the same cluster. About 65 species were classified into ten homogeneous clusters from the analysis of 29 reproductive traits, among which the most important were temperature during spawning, egg incubation and larval rearing, degree-days for incubation, larval size upon hatching, spawning season, and parental care. From this typology, a rather regular continuum of reproductive clusters emerges with two obvious endpoints. Between these two extremes, species could be ordered chiefly according to temperature requirement, spawning season and parental care. In conclusion, this new typology, differing significantly from all others proposed earlier, may now serve as a possible framework to help enhancing the domestication of new species by comparison to species belonging to the same cluster.