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1.
Arboreal termites (Nasutitermes spp.) and stomach contents from tamanduas (Tamandua tetradactyla) were collected in central Venezuela during the mid part of the dry season (March) of 1993 and 1994. Nutritional analyses were performed on each caste (workers n = 3), soldiers (n = 5), and alates [n = (1]), on mixed caste samples (n = 1), and on stomach contents from live (n = 5) and roadkill (n = 5) tamanduas. The chemical analysis, expressed on a dry matter (DM) basis, of termite workers, which constituted the majority of the nest populations, showed the highest crude protein (CP) (67%) and the lowest DM (25%) and fat (2%) values. Ash content varied from a low of 4% in alates to a high of 7% in soldiers. The alates contained substantially higher DM (41%) and fat (40%), which was reflected in a higher caloric value (6.88 kcal/g) (gross energy) [GE], and relatively less CP (49%). Among the macrominerals, potassium (K) was consistently the highest, with an overall mean value of 0.54%, while the calcium (Ca) and phosphorus (P) levels showed overall means of 0.26% and 0.67%, respectively. Iron (Fe) was the highest among the trace minerals but highly variable (soldiers, 1,000 ppm; alates, 246 ppm; workers, 394 ppm). Differences in the concentrations of vitamin A and E were found among termites castes, with soldiers showing the highest values (20 and 85 μg/g for retinol and α-tocopherol, respectively). Acid detergent fiber (ADF) was lower in the alates (13%) and workers (27%) compared to the soldiers (35%). Alates' fat was more saturated (39%), while soldiers and workers had a much higher polyunsaturated fatty acid (PUFA) concentration. In general, similar nutrient profiles were found between the tamandua stomach contents and the overall mean composition of Nasutitermes spp. However, stomach contents had much higher ADF, ash, and Fe concentrations (31%, 14%, and 2,748 ppm) than termites (25%, 5%, and 652 ppm) but lower CP, fat, GE, and Ca values (51%, 11%, 4.58 kcal/g, and 0.11% vs. 58%, 15%, 6.01 kcal/g, and 0.26% in termites). The relatively low concentrations of Ca in both stomach contents and termites may be indicative of a low requirement in Myrmecophaga compared to other mammalian species. Diets consumed by free-ranging tamanduas contained on a DM basis 51% CP, 11% fat, 14% ash, 31% ADF, 4.58 kcal/g GE, 0.11% Ca, 0.41% P, 2.52 μg/g retinol, and 44.3 μg/g α-tocopherol. Duplication of these nutrient profiles might greatly benefit captive health and reproduction of this species. © 1996 Wiley-Liss, Inc.  相似文献   

2.
There is a growing ethical concern in modern society about animals' quality of life. We hypothesize that zoo visitors' perception of zoo animal welfare, particularly in the case of lesser anteaters, changes positively after listening to scientific information. Visitors observing active lesser anteaters in their enclosures at Córdoba Zoo (Argentina) were asked to respond to a questionnaire about animal welfare. The treatment group (T) answered the questionnaire after listening to a brief informative talk based on local scientific studies on lesser anteaters. The control group (C) answered the questionnaire without hearing the informative talk. Visitors (87.2%) considered biological, sanitary, and sociocultural aspects to be necessary conditions for optimum wild zoo‐housed animal welfare. The majority of visitors considered that natural surroundings provide the highest level of welfare for wild animals. Visitors in the T group ranked the zoo as providing a higher level of animal welfare than those in group C. In reference to management measurements, the T group agreed on the positive effect of the application of environmental enrichment (Likert Medians: C = 4 and T = 5; p = .0443). On the basis of their perception, most visitors in both groups stated that the lesser anteaters at Córdoba Zoo appeared to be in a good state of welfare. We interpret this as meaning that, what these Córdoba zoo visitors personally perceived while observing the lesser anteaters carried greater weight than what they learned from the informative talk, though the talk did slightly affect their opinion.  相似文献   

3.
Bullfrogs (Runa catesbeiana) are listed as one of the 100 worst invasive alien species in the world.They are generalist predators and thus may affect native species through predation.In previous studies,the food contents of bullfrogs were mostly examined at a single site.In the present study,the diet composition of post-metamorphic bullfrogs on eight islands (Daishan,Liuheng,Xiushan,Fodu,Taohua,Xiashi,Cezi,and Putuoshan) in the Zhoushan Archipelago,Zhejiang Province of China,were examined by using the stomach flushing method from June 30 to August 11 in 2005.A total 0f391 individual frogs were measured,including 113 adults and 278 juveniles.The analysis of the stomach contents shows that,for adult bullfrogs,the most important prey (by diet volume) overall were Decapoda,Coleoptera,Odonata,Mesogastropoda,Raniformes,and Cypriniformes.For juvenile bullfrogs,these were Decapoda,Coleoptera,Cypriniformes,Odonata,Orthoptera,Hymenoptera,Lepidoptera larvae,Mesogastropoda,and Raniformes.Moreover,the prey size and diet volume increased with the body size of both adult and juvenile bullfrogs.The diet composition of primary preys of bullfrogs was significantly different among the islands.The results indicate that bullfrogs exert different predatory influences on native fauna at different sites and that bullfrogs are generalist predators with extensive ecological impacts on native fauna.  相似文献   

4.
Hailstorms has been reported to cause mortality of mammals or birds around the world, but the effect of hailstorms on tropical avian species has seldomly been documented. In April 2020, a hailstorm hit Xishuangbanna in south China and was reported to kill 45 Asian Openbills. We estimated the effect of hail by doing fieldwork and interviews. We walked along transects to survey the local avian diversity 3 days after the hail; checked the dead species along the transect; and also interviewed 67 local villagers in 14 villages in the impacted area. We found no evidence that other species were killed by the hail and recorded 40 bird species along the transects in April. Four months later, we surveyed the same transects and recorded 38 species, and the Asian Openbill stayed as one of the most dominant bird species. We concluded that the Asian Openbill is more vulnerable to hail compared with other local birds, but this single hail event did not have an obvious long‐term impact on the population. The result provided an important case study for a tropical bird''s response to extreme climate events and we suggested more similar observations to be made in the future.  相似文献   

5.
Bullfrogs (Rana catesbeiana) are listed as one of the 100 worst invasive alien species in the world. They are generalist predators and thus may affect native species through predation. In previous studies, the food contents of bullfrogs were mostly examined at a single site. In the present study, the diet composition of post-metamorphic bullfrogs on eight islands (Daishan, Liuheng, Xiushan, Fodu, Taohua, Xiashi, Cezi, and Putuoshan) in the Zhoushan Archipelago, Zhejiang Province of China, were examined by using the stomach flushing method from June 30 to August 11 in 2005. A total of 391 individual frogs were measured, including 113 adults and 278 juveniles. The analysis of the stomach contents shows that, for adult bullfrogs, the most important prey (by diet volume) overall were Decapoda, Coleoptera, Odonata, Mesogastropoda, Raniformes, and Cypriniformes. For juvenile bullfrogs, these were Decapoda, Coleoptera, Cypriniformes, Odonata, Orthoptera, Hymenoptera, Lepidoptera larvae, Mesogastropoda, and Raniformes. Moreover, the prey size and diet volume increased with the body size of both adult and juvenile bullfrogs. The diet composition of primary preys of bullfrogs was significantly different among the islands. The results indicate that bullfrogs exert different predatory influences on native fauna at different sites and that bullfrogs are generalist predators with extensive ecological impacts on native fauna. __________ Translated from Biodiversity Science, 2006, 14 (5): 363–371 [译自: 生 物多样性]  相似文献   

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8.
Tamandua tetradactyla (Pilosa), the lesser anteater, is a medium‐size mammal from South America. Its wide distribution through different landscapes, solitary and nocturnal habits, and the difficulty to capture and contain specimens limit the amount of individuals and populations sampled during fieldworks. These features along with the lack of specific molecular markers for the lesser anteater might be the causes for paucity in population genetic studies for the species. Historical samples from museum specimens, such as skins, and non‐invasive samples, such as plucked hair, can be supplementary sources of DNA samples. However, the DNA quantity and quality of these samples may be limiting factors in molecular studies. In this study, we describe nine microsatellite loci for T. tetradactyla and test the amplification success, data reliability and estimate errors on both historical and non‐invasive sample sets. We tested nine polymorphic microsatellites and applied the quality index approach to evaluate the relative performance in genotype analysis of 138 historical samples (study skin) and 19 non‐invasive samples (plucked hair). The observed results show a much superior DNA quality of non‐invasive over historical samples and support the quality index analysis as a practical tool to exclude samples with doubtful performance in genetic studies. We also found a relationship between the age of non‐invasive samples and DNA quality, but lack of evidence of this pattern for historical samples.  相似文献   

9.
  1. Predicting the likelihood of wildlife presence at potential wildlife–livestock interfaces is challenging. These interfaces are usually relatively small geographical areas where landscapes show large variation over small distances. Models of wildlife distribution based on coarse data over wide geographical ranges may not be representative of these interfaces. High‐resolution data can help identify fine‐scale predictors of wildlife habitat use at a local scale and provide more accurate predictions of species habitat use. These data may be used to inform knowledge of interface risks, such as disease transmission between wildlife and livestock, or human–wildlife conflict.
  2. This study uses fine‐scale habitat use data from wild boar (Sus scrofa) based on activity signs and direct field observations in and around the Forest of Dean in Gloucestershire, England. Spatial logistic regression models fitted using a variant of penalized quasi‐likelihood were used to identify habitat‐based and anthropogenic predictors of wild boar signs.
  3. Our models showed that within the Forest of Dean, wild boar signs were more likely to be seen in spring, in forest‐type habitats, closer to the center of the forest and near litter bins. In the area surrounding the Forest of Dean, wild boar signs were more likely to be seen in forest‐type habitats and near recreational parks and less likely to be seen near livestock.
  4. This approach shows that wild boar habitat use can be predicted using fine‐scale data over comparatively small areas and in human‐dominated landscapes, while taking account of the spatial correlation from other nearby fine‐scale data‐points. The methods we use could be applied to map habitat use of other wildlife species in similar landscapes, or of movement‐restricted, isolated, or fragmented wildlife populations.
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10.
This study provides insights into the dispersal potential of Platyrrhinus lineatus and its role in habitat regeneration. The study site was an urbanized area in northeastern Brazil. Fecal samples were collected at the roost of a colony during 13 months. Seven species were present in the samples, three of which were exotic. Cecropia glaziovii, Solanum stipulaceum and Coccothrinax barbadensis predominated in the diet of the colony. The large numbers of seeds of pioneer species, and the exotic species present in the diet of the colony emphasize the role of P. lineatus in the regeneration of habitats, and its ecological flexibility.  相似文献   

11.
A 24 h study of stomach contents and simultaneous sampling of the drift and benthos was used to describe the diet and assess the prey selectivity of Cox's gudgeon, Gobiomorphus coxii , within a small coastal stream in south-eastern Australia. Prey items consisted entirely of macroinvertebrates with most being ephemeropterans and trichopterans. The greatest number and largest volume of macroinvertebrates were in the stomachs of fish collected just after sunset through until several hours after sunrise. Both the number of empty stomachs and proportion of digested material in the stomach contents peaked at mid-day. Overall, it was concluded that G. coxii was a nocturnal feeder that specialized on benthos, although some evidence of opportunistic prey selection was apparent. Gobiomorphus coxii was also size selective, preferring relatively large prey from both the drift and benthos.  相似文献   

12.
Predators appear to be less frequently specialised (i.e. adapted to restricted diet) on their prey than herbivores, parasites or parasitoids. Here, we critically evaluate contemporary evolutionary hypotheses that might be used to explain the evolution of specialised foraging in predators. We propose a unifying concept within which we define four types of trophic categories using ecological (diet breadth) and evolutionary (degree of adaptations) contexts. We use data on spiders (Araneae), the most diversified order of terrestrial predators, to assess applicability of frameworks and evolutionary concepts related to trophic specialisation. The majority of spider species are euryphagous but a few have a restricted prey range, i.e. they are stenophagous. We provide a detailed overview of specialisation on different prey types, namely spiders, crustaceans, moths, dipterans, ants, and termites. We also review the available evidence for trophic adaptations, classified into four categories: behavioural, morphological, venomic and metabolic. Finally, we discuss the ecological and evolutionary implications of trophic specialisation and propose avenues for future research.  相似文献   

13.
The species composition and seasonal dynamics of water mites were studied in a small softwater stream in southern Germany from October 1986 to November 1988. On average water mites contributed 5.5% by abundance and 1.8% by biomass to the total invertebrate community. Annual densities and biomasses averaged 623–1057 (mean 905) individuals M–2 and 45.9–75.6 mg (mean 64.0) dry mass m–2, respectively. 41 species were identified, Torrenticola elliptica (Torrenticolidae) being the most abundant. Nearly every taxon showed a distinct and consistent seasonality, with maximum abundance and biomass in summer and minimum values in winter. Both abundance and biomass of water mites were significantly correlated with water temperature (p < 0.001).  相似文献   

14.
High‐throughput DNA sequencing technologies make it possible now to sequence entire genomes relatively easily. Complete genomic information obtained by whole‐genome resequencing (WGS) can aid in identifying and delineating species even if they are extremely young, cryptic, or morphologically difficult to discern and closely related. Yet, for taxonomic or conservation biology purposes, WGS can remain cost‐prohibitive, too time‐consuming, and often constitute a “data overkill.” Rapid and reliable identification of species (and populations) that is also cost‐effective is made possible by species‐specific markers that can be discovered by WGS. Based on WGS data, we designed a PCR restriction fragment length polymorphism (PCR‐RFLP) assay for 19 Neotropical Midas cichlid populations (Amphilophus cf. citrinellus), that includes all 13 described species of this species complex. Our work illustrates that identification of species and populations (i.e., fish from different lakes) can be greatly improved by designing genetic markers using available “high resolution” genomic information. Yet, our work also shows that even in the best‐case scenario, when whole‐genome resequencing information is available, unequivocal assignments remain challenging when species or populations diverged very recently, or gene flow persists. In summary, we provide a comprehensive workflow on how to design RFPL markers based on genome resequencing data, how to test and evaluate their reliability, and discuss the benefits and pitfalls of our approach.  相似文献   

15.
Nonindigenous species may exert strong effects on ecosystem structure and function. The zebra mussel (Dreissena polymorpha) has been attributed with profound changes in invaded ecosystems across eastern North America. We explored vertical profiles of water flow velocity and chlorophyll a concentration in western Lake Erie, over rocky substrates encrusted with Dreissena, to assess the extent to which mussels influence coupling between benthic and pelagic regions of the lake. Flow velocity was always low at surveyed sites (less than or equal to 2.9 cm s-1) and declined in direct proximity to the lakebed. Mean chlorophyll a concentration was also low (less than 5μg L-1) at all sites and depths. Chlorophyll a concentration was positively correlated with distance above lakebed and was lowest (0.3μg L-1) directly adjacent to the lakebed. Spatial patterns of zooplankton grazers could not explain observed vertical gradients in chlorophyll concentration. Hydrodynamic modeling revealed that filtering effects of Dreissena in a nonstratified, shallow basin depend mainly on upstream chlorophyll concentration, intensity of turbulent diffusion, feeding efficiency of the mussel colony, and the distance downstream from the leading edge of the mussel colony. In contrast to widespread perceptions that molluscs reduce phytoplankton concentration only adjacent to the lakebed, modeling scenarios indicated that depletion occurs throughout the water column. Depletion was, however, inversely proportional to distance above the lakebed. Simulation results are consistent with field-based observations made in shallow water habitats populated by large Dreissena populations in the Great Lakes and elsewhere. Results from this study indicate that zebra mussels strongly enhance coupling between pelagic and benthic regions in shallow lakes. Enhanced coupling between these regions explains, in part, high population densities of Dreissena and of many benthic invertebrates in ecosystems invaded by zebra mussels. Received 14 July 1998; accepted 25 March 1999.  相似文献   

16.
Rapidly changing climate is likely to modify the spatial distribution of both flora and fauna. Land use change continues to alter the availability and quality of habitat and further intensifies the effects of climate change on wildlife species. We used an ensemble modeling approach to predict changes in habitat suitability for an iconic wildlife species, greater one‐horned rhinoceros due to the combined effects of climate and land use changes. We compiled an extensive database on current rhinoceros distribution and selected nine ecologically meaningful environmental variables for developing ensemble models of habitat suitability using ten different species distribution modeling algorithms in the BIOMOD2 R package; and we did this under current climatic conditions and then projected them onto two possible climate change scenarios (SSP1‐2.6 and SSP5‐8.5) and two different time frames (2050 and 2070). Out of ten algorithms, random forest performed the best, and five environmental variables—distance from grasslands, mean temperature of driest quarter, distance from wetlands, annual precipitation, and slope, contributed the most in the model. The ensemble model estimated the current suitable habitat of rhinoceros to be 2610 km2, about 1.77% of the total area of Nepal. The future habitat suitability under the lowest and highest emission scenarios was estimated to be: (1) 2325 and 1904 km2 in 2050; and (2) 2287 and 1686 km2 in 2070, respectively. Our results suggest that over one‐third of the current rhinoceros habitat would become unsuitable within a period of 50 years, with the predicted declines being influenced to a greater degree by climatic changes than land use changes. We have recommended several measures to moderate these impacts, including relocation of the proposed Nijgad International Airport given that a considerable portion of potential rhinoceros habitat will be lost if the airport is constructed on the currently proposed site.  相似文献   

17.
A brachiopod fauna including 19 species of 17 genera from an exotic block in the Indus–Tsangpo suture zone in southern Tibet is described and illustrated. The brachiopod fauna is dominated by Martinia elegans and two new taxa: Jinomarginifera lhazeensis gen. et sp. nov. and Zhejiangospirifer giganteus sp. nov. The fauna is closely comparable with those from the middle and upper parts of the Wargal Formation and the Chhidru Formation in the Salt Range of Pakistan, the Chitichun Limestone in southern Tibet, and the Basleo area of West Timor, and these correlations suggest a Wuchiapingian age. The fauna exhibits substantial links with both peri–Gondwanan and Cathaysian faunas, which may imply that it is a seamount biota originally located in the southern margin of the Neotethys during the Late Permian, and was later (in the early Cenozoic) displaced and became sandwiched into younger marine deposits in the collision process between India and Eurasia.  相似文献   

18.
Understanding the processes that underpin adaptive evolutionary shifts within major taxonomic groups has long been a research directive among many evolutionary biologists. Such phenomena are best studied in large monophyletic groups that occupy a broad range of habitats where repeated exposure to novel ecological opportunities has happened independently over time in different lineages. The gekkonid genus Cyrtodactylus is just such a lineage with approximately 300 species that range from South Asia to Melanesia and occupy a vast array of habitats. Ancestral state reconstructions using a stochastic character mapping analysis of nine different habitat preferences were employed across a phylogeny composed of 76% of the known species of Cyrtodactylus. This was done in order to ascertain which habitat preference is the ancestral condition and from that condition, the transition frequency to more derived habitat preferences. The results indicate that a general habitat preference is the ancestral condition for Cyrtodactylus and the frequency of transitioning from a general habitat preference to anything more specialized occurs approximately four times more often than the reverse. Species showing extreme morphological and/or ecological specializations generally do not give rise to species bearing other habitat preferences. The evolution of different habitat preferences is generally restricted to clades that tend to occur in specific geographic regions. The largest radiations in the genus occur in rocky habitats (granite and karst), indicating that the transition from a general habitat preference to a granite or karst‐dwelling life style may be ecologically uncomplicated. Two large, unrelated clades of karst‐associated species are centered in northern Indochina and the largest clade of granite‐associated species occurs on the Thai‐Malay Peninsula. Smaller, independent radiations of clades bearing other habitat preferences occur throughout the tree and across the broad distribution of the genus. With the exception of a general habitat preference, the data show that karst‐associated species far out‐number all others (29.6% vs. 0.4%–10.2%, respectively) and the common reference to karstic regions as “imperiled arcs of biodiversity” is not only misleading but potentially dangerous. Karstic regions are not simply refugia harboring the remnants of local biodiversity but are foci of speciation that continue to generate the most speciose, independent, radiations across the genus. Unfortunately, karstic landscapes are some of the most imperiled and least protected habitats on the planet and these data continue to underscore the urgent need for their conservation.  相似文献   

19.
A leafminer of the Nearctic genus Coptodisca Walsingham (Lepidoptera: Heliozelidae), a species of potential economic interest, is reported for the first time from Europe, infesting the black (Juglans nigra L.) and the common walnut (Juglans regia L.). Mines were collected since September of 2010 in several sites of two Italian regions (Campania and Lazio). The species is rather similar to Coptodisca juglandella (Chambers), the only Coptodisca known to attack walnuts, but at present, an unambiguous identification cannot be provided because of the unsatisfactory characterization of this leafminer and congeneric species. Three generations were recorded per year and leafminers overwinter as mature larvae. The first adults emerged in May–June while mature larvae of the last generation started the overwintering in September. During the last generation of the year, infestation levels of leaves were 100% in all sampled localities. Several species of parasitoids were reared from infested mines, with specimens belonging to the genus Chrysocharis (Hymenoptera: Eulophidae) being the most frequent parasitoids.  相似文献   

20.
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