Spatial variance-mass allometry of population density in felids from camera-trapping studies worldwide.

Power laws are cornerstone relationships in ecology and evolutionary biology. The density-mass allometry (DMA), which predicts an allometric scaling of population abundance, and Taylor's law (TL), which predicts a decrease in the population abundance variation along with a decrease in population density, have enhanced our knowledge of inter- and intra-specific variation in population abundance. When combined, these two power laws led to the variance-mass allometry (VMA), which states that larger species have lower spatial variation in population density than smaller species. The VMA has been predicted through theoretical models, however few studies have investigated if this law is also supported by empirical data. Here, to formally test the VMA, we have used the population density estimates obtained through worldwide camera trapping studies for an emblematic and ecologically important carnivorous taxa, the Felidae family. Our results showed that the VMA law hold in felids, as well as the TL and the DMA laws; bigger cat species showed less variation for the population density than smaller species. These results have important implications for the conservation of wildlife population and confirm the validity of important ecological concepts, like the allometric scaling of population growth rate and the slow-fast continuum of life history strategies.

Survey on parasitic infections in wildcat (Felis silvestris silvestris Schreber, 1777) by scat collection.

Wildcats are endangered felid species living in Europe, Asia, and Africa. Regrettably, scientific information on parasites of wildcats is particularly meager and they often rely on data gained by necropsies of a small number of animals. In the present study, scat collection was used to assess the parasite spectrum of European wildcats living in the Etna Park (Sicily, Italy). Scat collection was performed from May to September 2010 by weekly walking four transects for a total of 391 km. Samples were then analyzed by flotation and sedimentation techniques to investigate wildcat parasitic fauna. A total of 121 scats of wildcats were collected, and parasitic forms (i.e., oocysts, eggs, and larvae) were retrieved in 110 (90.9 %) of the samples. Parasites found were Physaloptera sp. (52.1 %), tapeworms (45.5 %), Toxocara cati (43.8 %), Eucoleus aerophilus (27.3 %), Ancylostoma sp. (22.3 %), Troglostrongylus brevior (15.7 %), trematodes (9.9 %), Isospora felis (4.1 %), Cylicospirura sp. (1.7 %), and Acanthocephala (0.8 %). The prevalence of endoparasitic infections herein recorded is similar to that described in other studies conducted using necropsy technique. The species richness of parasites found in the present survey, with a total of nine helminths and one protozoon, is the highest ever reported for wildcat in Europe. Scat collection and examination are reliable and rapid non-invasive tools which can be used in a systematic survey design to study the parasite spectrum of wildcat as well as that of other endangered wild species.