The Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its natural diet remains largely undetermined, especially in relation to seasonal variations in ...food availability. From March to November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availability in the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 different prey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in the Coleoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of the prey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study shows that the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability. However, seasonal variations were observed in prey selection, and a notable shift in food preference was observed during autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably in relation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality.
•Ant morphological traits are a species level surrogate of food use ecology.•These relationships are affected by subfamily and (less) by habitat type.•Trait distribution loosely predicted food use ...intensity by entire communities.•Further research is need to disentangle trait–ecosystem function relationships.
I investigated whether the morphological traits of Neotropical ants can be used to infer food resource use by individual species and by entire communities, and whether these relationships are related to habitat type and/or by morphological differences between ant subfamilies. I attracted ants using food baits that represented different ecological processes (e.g. predation, granivory, detritivory, nectarivory) in five habitat types along a land-use gradient (from forests to gardens). I assessed ant activity at the baits and characterized 64 species from six subfamilies according to their food use and community-level resource exploitation intensity in the different habitats. Next, I performed a Mantel test to reveal the relationships between 13 morphological measures and resource use at the species level. I then used ant clades (i.e. subfamily) and habitat to rank the ants along three axes of variation in relation to their morphology and food resource use. Finally, I tested whether associations existed between the community-level exploitation intensity for such resources and the distribution of morphological trait values using the “4th-corner” analysis. Morphological traits were closely linked to the species’ ability to exploit different resources. These relationships were affected by subfamily and, to a lesser extent, by habitat type. The characterization of trait sets for entire communities was not useful, however, in predicting the intensity of the exploitation of different types of resources in varying environmental conditions. I conclude that morphological traits are accurate predictors of the ecology of species, but they should be used with caution when trying to understand community-level patterns.
We investigated food niches, diet diversity and individual food specialization of the larvae and adults of four species of ladybirds, Sospita vigintiguttata (L.), Calvia quindecimguttata (F.), C. ...quatuordecimguttata (L.) and C. decemguttata (L.), cooccurring in European alder carr forests. The fi rst two species are considered to be strict habitat specialists associated with alders (Alnus spp.) in marshy forests and the other two are less habitat-specialized, inhabiting various deciduous trees and shrubs. Our investigations were based on the analysis of food remains in frass produced by field-collected ladybirds. In each of the species studied, adults had more diversified diets than larvae based on Levins' D index of diversity. The most diverse diet recorded for adults was that for S. vigintiguttata followed by C. quatuordecimguttata, C. quindecimguttata and C. decemguttata. The diversity of larval diet was higher for the habitat specialists, C. quindecimguttata and S. vigintiguttata, than for the more habitat-generalists Calvia decemguttata and C. quatuordecimguttata. Although the main type of prey recorded for both adults and larvae of each of the species studied was aphids, other types of prey made up a relatively high part of the diet of different species/stage combinations. Psylla alni (L.), for example, was frequently recorded in the frass of adults and larvae of S. vigintiguttata and of adults of C. quatuordecimguttata and chrysomelid larvae commonly in the frass of adults and larvae of C. quindecimguttata. Quite a high proportion of the frass of all the species studied contained the remains of Psocodea. The niche width of adults was broader than that of larvae except in C. quindecimguttata in which it was the opposite. The larval niches of the strict habitat specialists, C. quindecimguttata and S. vigintiguttata, were broader than those of the less habitat-specialists C. decemguttata and C. quatuordecimguttata. Adults of all the species studied showed relatively higher levels of food specialization than larvae, except for C. quindecimguttata. The results of this study indicate that ecological specialization is a complex phenomenon and habitat specialization does not imply food specialization.
Individual-level diet variation was investigated in Gracilinanus microtarsus, an insectivorous marsupial whose diet is affected by sex and season in the highly seasonal Brazilian Cerrado. To measure ...individual-level diet variation, the diets of individual males and females were compared to that of their population in the warm-wet and cool-dry seasons using the proportional similarity index (PSi). This index varies from 1 (complete overlap between the individual i 's and population's diets) toward 0 (decreasing overlap). Mean PSi values were computed as a measure of the degree of interindividual diet variation (the larger the mean PSi value, the smaller the variation among individuals' diets). Interindividual diet variation among females was similar between seasons, whereas among males it decreased from the warm-wet to the cool-dry season. Diet variation among males is probably reduced in the cool-dry season because of constraints on food consumption generated by interactions between endogenous (physiological needs associated with high rates of body mass growth) and exogenous (food limitation) factors.
In this study, we evaluated if railway embankments and road verges create refuge habitats for bee flora across agricultural landscape. The survey was conducted in 2009–2012, in the Lublin Province, ...SE Poland. Data on the bee forage flora were obtained while making floristic charts along 60 transect plots × 300 m, with a total length of 18 000 m, for each type of linear structure. Forage bee flora was compared with respect to species richness, diversity, and evenness indices. The canonical correspondence analysis (CCA) was used to characterize relationship between species composition and environmental variables. The bee forage species richness and abundance were significantly greater on railway embankments than on road verges. The composition of species varied considerably; the number of bee forage species common to both habitats was only approximately 38% in entire data set. Most good-value bee forage species were recorded along the embankments of railways with an intermediate traffic volume. Bee forage species diversity benefits from the location of habitat elements (forests or meadows), primarily if the distance is <50 m. The lack of dense patches of valuable bee forage species in the road verges was related to the high density of non-nectariferous graminoids. Our results demonstrate how the value of man-made areas in an agricultural ecosystem can vary with respect to floral resources across the landscape, suggesting that it is inappropriate to generalize about agricultural systems as a whole without first addressing differences among habitats.
The study of the diet of fish is an important tool to assess different levels of environmental degradation, since the availability of food in the environment is a key factor for the fish occurrence. ...The removal of riparian vegetation usually degrades environmental quality, as this vegetation has an important role in providing energy to the ecosystem. This study investigates the effects of the removal of riparian vegetation on the fish assemblage trophic network. The study was carried out in two stretches of a southeastern Brazilian stream, one in a forest fragment and another in a pasture, during the wet and dry seasons of 2014. We analyzed the items consumed by each fish species using the frequency of occurrence and area of each item, which were combined to calculate the alimentary index, which was used to determine the food niche overlap of the fish and the specialization index of the trophic network. Aquatic Hexapoda, vegetal debris and organic matter dominated the trophic network of the two stretches. We detected higher values of food niche overlap in the forested stretch and more complex trophic networks in the pasture stretch. We found few seasonal variations in the items consumed and calculated indices in both stretches studied. The presence of grass on the banks in the pasture stretch and the importation of food resources from the upstream area may have provided a higher diversity of resources and consequently showed a more complex trophic network when compared to the forested stretch.
The Yellow-footed Gull (Larus livens) is one of the few members of the genus Larus inhabiting the Gulf of California. Its breeding biology, nest phenology, and behavior have been long studied but ...little is known about seasonal changes in its diet. In this study, we tested if the diet of Yellow-footed Gull differed between reproductive (April and July) and non-reproductive (December). The frequency of occurrence of food items in gull's pellets and food niche breadth (FNB) and Levin's diversity (Best) indexes for each sampling period (April, July, and December), as well as Pianka's dietary overlap (O%) and Morisita's (MI) dietary similarity indices between periods were estimated. We identified 9 taxa classes, whose frequency of occurrence varied significantly between all comparisons (April and December, July and December, April and July), and between reproductive (April–July) and non-reproductive seasons. FNB and Best diversity indexes indicated that Yellow-footed Gull has a broader niche spectrum during the breeding season (April–July), while dietary overlap estimators (O% and MI) were higher between July vs. December and April vs. December, but lower in April vs. July. Results are contrasted with previous studies of gull's feeding ecology, and possible effects of local human activity are discussed.
La gaviota de patas amarillas (Larus livens) es uno de los pocos miembros del género Larus que habitan el Golfo de California. Su biología reproductiva, fenología de nido y comportamiento se han estudiado durante mucho tiempo, pero poco se sabe acerca de los cambios estacionales en su dieta. En este estudio se probó si la dieta de la gaviota de patas amarillas fue diferente entre temporadas reproductivas (abril y julio) y no reproductivas (diciembre). Se evaluó la frecuencia de presencia en egagrópilas, la amplitud de nicho trófico (FNB) y el índice de diversidad de Levin (Best) para cada período de muestreo (abril, julio y diciembre), así como la superposición de la dieta de Pianka (O%) y el índice de similitud de Morisita (MI) entre períodos. Se identificaron 9 clases de taxones, en los que la frecuencia varió significativamente entre todas las comparaciones (abril y diciembre, julio y diciembre, abril y julio) y entre los períodos reproductivos (abril-julio) y no reproductivos. Los índices FNB y Best indicaron que la gaviota de patas amarillas tiene un espectro de nicho más amplio durante la temporada reproductiva (abril-julio), mientras que los estimadores de solapamiento dietéticos (O% y MI) fueron más altos entre julio vs. diciembre y abril vs. diciembre, pero menor en abril vs. julio. Los resultados se contrastan con estudios previos de ecología de alimentación de gaviotas y se discuten los posibles efectos de la actividad humana local.
The Long-eared Owl (Asio otus) is a widely distributed predator with plastic foraging habits. Its diet has been studied across most of Europe and North America, but little information is available on ...intra-seasonal diet variation. We studied the winter diet of Long-eared Owls in a Mediterranean fragmented farmland. Diet was dominated by small mammals (mostly Apodemus spp.), with birds the second most abundant group. In our landscape, the amount of bird prey items in the diet was higher compared to values reported from other areas of Italy. There was relatively large variation in the diet among the three months of study. Our study confirms the pattern of higher Long-eared Owl diet diversity in a Mediterranean landscape compared to that reported for other regions of Europe where the diversity of prey species may be lower. The findings suggest that extensively-managed Mediterranean rural landscapes can provide habitat suitable for the Long-eared Owl, as they offer a wide diversity of food sources that may be exploited by this nocturnal predator.
We investigated the diet, feeding strategy, size-related dietary shifts and prey preferences of South American Hoplias aff. malabaricus in an internationally recognized but poorly investigated ...Biosphere Reserve in southern Brazil. Fish were caught between April 2008 and March 2009 using a variety of fishing gear. The analysis of 113 individuals revealed a diet essentially composed of fish (16 species), particularly characid species (9). The diet became more diverse and contained larger fish prey with increasing predator size. Feeding strategy analysis revealed a clear specialization towards the consumption of fish. However, individuals did not prey upon particular prey species, instead opportunistically consuming many different fish species, which could be a strategy to avoid intraspecific competition. Characid species were the most important prey, followed by poecillids. A multi-gear sampling of the ichthyofauna revealed that these prey species were the most abundant (Characidae: 61.3%, Poeciliidae 18.8%) of the 14 fish families occurring at the study site, suggesting that the predator exploits the most abundant fish resources available rather than the rarer fish prey. These findings suggest that potential top-down controls exerted by H. aff. malabaricus in this system follow specific food web pathways that seem to be mediated by the abundance of prey resources.
Comparisons of sympatric reptile species were used to assess the variation in niche overlap for food between potential competitors at different trophic levels. Omnivorous tortoises and carnivorous ...vipers inhabiting the rain-forest region of West Africa were used as study models. Food niche overlap between species increased with habitat alteration in both the independent study systems: tortoises (Kinixys homeana and Kinixys erosa) and vipers (Bitis gabonica and Bitis nasicornis) showed lower values of Pianka's niche overlap index in the pristine habitat than in the altered habitat, and these differences in overlap values did not depend on chance after Monte Carlo simulations. There were higher inter-habitat food niche overlaps within-species than between-species. Permutation tests (assessed after 5000 iterations) revealed that, for both study systems, the P-values became significantly smaller with fewer resource states, thus showing the niche overlap between species really increases after habitat alteration. The observed increases in food niche overlap between species accomplished with rain-forest habitat degradation in turn may be predicted to have cumulative effects on reducing the level of forest biodiversity.
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