Spatial behaviour of the Apennine hare: Are females territorial?

The spatial behaviour of seven male and five female Apennine hares Lepus corsicanus was studied in a scrub-wood area of Central Italy, through radiotracking. The median percentage of home-range overlap was about five times lower between females (< 15%) than between males (75%). Intrasexual aggression was recorded for females, but never for males. No species within the Lepus genus are known to be territorial, whereas we suggest that inter-individual female intolerance in the Apennine hare may be compatible with territoriality. The Apennine hare is also unusual among hares because it reproduces throughout the year, that is also during food-poor months, which could have triggered resource defence between females to maximise their reproductive fitness.     

Information use by an Invading Species: Do Invaders Respond More to Alarm Odors than Native Species?

Two species of crayfish were tested in the laboratory to evaluate the hypothesis that successful invaders use a broader range of chemical information than do displaced native species. The invasive species Orconectes rusticus reduced responses to food odors just as strongly when heterospecific (O. propinquus, O. virilis) alarm odors were introduced with food odors as they did when conspecific alarm odors were introduced at the same time as food odors. Individuals of the displaced native species, O. propinquus, did not reduce feeding responses as strongly when O. virilis alarm odor was introduced as with conspecific alarm odor or O. rusticus alarm odor. These results are consistent with the hypothesis that successful invaders use a wider range of information about their environment than do displaced native species.     

Chilling-Induced Photoinhibition in Two Oak Species: Are Evergreen Leaves Inherently Better Protected Than Deciduous Leaves?

We compared the sensitivity to cold stress, in terms of photosynthetic capacity and changes in chlorophyll fluorescence of photosystem 2 (PS2), of an evergreen and a deciduous oak species, which co-occur in the southeastern United States. We predicted that the evergreen species, Quercus virginiana, which must endure winter, is likely to have an inherently greater capacity for energy dissipation and to be less susceptible to chilling stress than the deciduous species, Quercus michauxii. Short-term cold stress in both species lead to greater than 50 % reduction in maximum photosynthetic rates, 60-70 % reduction in electron transport, and irreversible quenching of PS2 fluorescence. The kinetics of recovery in the dark after exposure to 1 h high irradiance (1000 μmol m^-2 s^-1) and chilling (5 °C) showed that the evergreen Q. virginiana exhibited more protective q_E and less irreversible quenching (q_I) than the deciduous Q. michauxii. The large q_E which we observed in Q. virginiana suggests that the capacity for photoprotection at low temperatures is not induced by a long-term acclimation to cold but preexists in evergreen leaves. This capacity may contribute to the ability of this species to maintain leaves during the winter. This revised version was published online in June 2006 with corrections to the Cover Date.     

Chilling-Induced Photoinhibition in Two Oak Species: Are Evergreen Leaves Inherently Better Protected Than Deciduous Leaves?

We compared the sensitivity to cold stress, in terms of photosynthetic capacity and changes in chlorophyll fluorescence of photosystem 2 (PS2), of an evergreen and a deciduous oak species, which co-occur in the southeastern United States. We predicted that the evergreen species, Quercus virginiana, which must endure winter, is likely to have an inherently greater capacity for energy dissipation and to be less susceptible to chilling stress than the deciduous species, Quercus michauxii. Short-term cold stress in both species lead to greater than 50 % reduction in maximum photosynthetic rates, 60-70 % reduction in electron transport, and irreversible quenching of PS2 fluorescence. The kinetics of recovery in the dark after exposure to 1 h high irradiance (1000 µmol m^-2 s^-1) and chilling (5 °C) showed that the evergreen Q. virginiana exhibited more protective q_E and less irreversible quenching (q_I) than the deciduous Q. michauxii. The large q_E which we observed in Q. virginiana suggests that the capacity for photoprotection at low temperatures is not induced by a long-term acclimation to cold but preexists in evergreen leaves. This capacity may contribute to the ability of this species to maintain leaves during the winter.     

Do Sprouting Tree Species on Erosion-prone Sites Carry Large Reserves of Resources?

Saplings ofEuptelea polyandra were studied to determine whethertree species found on unstable hillslopes of temperate, old-growthforests in Japan carry substantial storage materials for sproutingreplacement genets, as is the case with resprouter species offire-prone areas. Concentrations (% d. wt basis) of carbohydrates(starch, sucrose, glucose and fructose) contained in roots,stems and leaves were measured in summer and winter.E. polyandrasaplings were compared with those ofQuercus serrata (a frequentlysprouting tree), and those ofMallotus japonicus andIdesia polycarpa(rarely sprouting trees) in the same forest. Total concentrationsof carbohydrates (the sum of starch, sucrose, glucose and fructose)in roots were lowest inE. polyandra in both summer and winter.In addition,E. polyandra had a lower ratio of root biomass tototal plant biomass thanQ. serrata , but similar to that ofthe non-sprouting species,M. japonicus andI. polycarpa . Onthe other hand, the total concentration of carbohydrates inthe above-ground parts were similar in the four species in bothsummer and winter. These results indicate thatE. polyandra hadless long-term storage resources to implement sprouting, inspite of its apparent effectiveness in sprouting. We proposehypotheses to explain the reason whyE. polyandra stores a relativelysmall amount of resources for sprouting. Carbohydrate concentration; Euptelea polyandra Sieb. et Zacc; ground-surface disturbance; Idesia polycarpa Maxim; Mallotus japonicus (Thunb.) Muell. Arg.; Quercus serrata Thunb.; resprouter; root dry weight ratio; soluble sugars; sprouting; starch     

Review of Mexican Species of Podogaster Brullé (Hymenoptera: Ichneumonidae: Anomaloninae) with Description of Two New Species

Two new species of Podogaster Brullé, Podogaster brunneus n. sp. and Podogaster lagartensis n. sp., are described. The material was collected with Malaise traps operated for a year in the Ría Lagartos Biosphere Reserve, a dry tropical area of Southeast Mexico. Podogaster rosteri Gauld & Bradshaw is synonymized with Podogaster mexicanus (Cresson). A key to the Mexican species is also provided.     

A Morphological and Molecular Perspective of Trichoderma viride: Is It One or Two Species?

Trichoderma (Ascomycetes, Hypocreales) strains that have warted conidia are traditionally identified as T. viride, the type species of Trichoderma. However, two morphologically distinct types of conidial warts (I and II) have been found. Because each type corresponds to a unique mitochondrial DNA pattern, it has been questioned whether T. viride comprises more than one species. Combined molecular data (sequences of the internal transcribed spacer 1 [ITS-1] and ITS-2 regions and of part of the 28S rRNA gene along with results of restriction fragment length polymorphism analysis of the endochitinase gene and PCR fingerprinting), morphology, physiology, and colony characteristics distinguish type I and type II as different species. Type I corresponds to “true” T. viride, the anamorph of Hypocrea rufa. Type II represents a new species, T. asperellum, which is, in terms of molecular characteristics, close to the neotype of T. hamatum.     

Habitat Association in Two Genetic Groups of the Insect-Pathogenic Fungus Metarhizium anisopliae: Uncovering Cryptic Species?

Strains of insect-pathogenic fungi with high virulence toward certain pest insects have great potential for commercial biological control applications. Identifying such strains has been a central theme in using fungi for biological control. This theme is supported by a persistent paradigm in insect pathology which suggests that the host insect is the predominant influence on the population genetics of insect-pathogenic fungi. In this study, a population genetics analysis of the insect-pathogenic fungus Metarhizium anisopliae from forested and agricultural habitats in Ontario, Canada, showed a nonrandom association of alleles between two distinct, reproductively isolated groups (index of multilocus association = 1.2). Analyses of the mitochondrial DNA showed no differences between the groups. The two groups were associated with different habitat types, and associations with insect hosts were not found. The group from forested areas showed an ability for cold-active growth (i.e., 8°C), while the group from the agricultural area showed an ability for growth at high temperatures (i.e., 37°C) and resilience to UV exposure. These results represent a significant paradigm shift; habitat selection, not host insect selection, drives the population structure of these insect-pathogenic deuteromycetous fungi. With each group we observed recombining population structures as well as clonally reproducing lineages. We discuss whether these groups may represent cryptic species. Worldwide, M. anisopliae may be an assembly of cryptic species, each adapted to certain environmental conditions. The association of fungal genotypes with habitat but not with host insects has implications on the criteria for utility of this, and perhaps other, fungal biocontrol agents.     

Positive Interactions of Nonindigenous Species: Invasional Meltdown?

Study of interactions between pairs or larger groups of nonindigenous species has been subordinated in the literature to study of interactions between nonindigenous and native species. To the extent that interactions among introduced species are depicted at all, the emphasis has been on negative interactions, primarily resource competition and interference. However, a literature search reveals that introduced species frequently interact with one another and that facilitative interactions are at least as common as detrimental ones. The population significance of these interactions has rarely been determined, but a great variety of types of direct and indirect interactions among individuals of different nonindigenous species is observed, and many are plausibly believed to have consequences at the population level. In particular, mutualisms between plants and the animals that disperse and/or pollinate them and modification of habitat by both animals and plants seem common and often important in facilitating invasions. There is little evidence that interference among introduced species at levels currently observed significantly impedes further invasions, and synergistic interactions among invaders may well lead to accelerated impacts on native ecosystems – an invasional meltdown process.     

Optimal Reproduction Strategies in Two Species of Mound-Building Termites

We formulate a mathematical model for food collection and production of workers and nymphs in 2 species of mound building termites. We maximise the number of nymphs (reproductives) produced by each colony over its lifetime with respect to the proportion of eggs that hatch as nymphs as opposed to workers. The results predict that food storage has a very important influence on the pattern of nymph and worker production. Food storage affects the part of the year that nymph production dominates, whether nymphs and workers are produced at the same time or not, and the existence of a final phase in the colony’s life when a very large number of nymphs but no workers are produced.     

On the Occlusal Fit of Tribosphenic Molars: Are We Underestimating Species Diversity in the Mesozoic?

The complex occlusal fits between tribosphenic teeth are a rich source of information for taxonomic, phylogenetic, and evolutionary analysis. The degree of fit between upper and lower cheek teeth has been used to refer specimens to species-level taxa, but statistical data on occlusal fit in relation to taxonomic identity have been lacking. We used landmarks on upper and lower first molars of 20 bat populations representing 16 species to assess the degree of occlusal fit (1) between teeth from the same individual; (2) between teeth from different individuals belonging to the same populations; and (3) between teeth belonging to different populations. We found that the fit of teeth belonging to different populations was significantly worse than between those of the same population and that the degree of misfit increased linearly with time since common ancestry, albeit with substantial variance. We used our comparisons to assess the species-level diversity within Batodon, the smallest known placental mammal from the Cretaceous. Our data suggest, with caveats, that instead of belonging to a single species, the specimens assigned to Batodon represent at least two species as different as those belonging to different genera or families of living bats.     

Evaluating Potential Effects of Exotic Freshwater Fish From Incomplete Species Presence–absence Data

Many freshwater ecosystems and biotas around the world are threatened with extinction. Freshwater fishes, for example, are the most endangered vertebrates after amphibians. Exotic fish are widely recognized as a major disturbance agent for native fish. Evaluating the ecological effects of invaders presents many challenges and the problem is greatly augmented in parts of the world where the native fauna is poorly known and where exotic species are commonplace. We use the fish community of Patagonia, a small and distinct native biota dominated by exotic salmonids, as a case study to ask: what can we learn about the effects of exotic fish species from fragmentary or partial data and how do such data point the way to what needs to be learned? We review the available data and literature on the distribution and status of native and introduced fish. We compile a novel regional presence/absence species database, build fish distribution maps, describe distribution patterns of native and exotic species, and identify critical information voids. A comparative review of literature from Patagonia and Australasia, where a similar native and exotic fish fauna is found, helps us to identify research priorities and promising management strategies for the conservation of native fish fauna. We conclude that the main challenge for fish conservation in Patagonia is to identify management strategies that could preserve native species while maintaining the quality of salmonid fisheries.     

Zoonotic Disease Risk and Life-History Traits: Are Reservoirs Fast Life Species?

The relationship between humans, wildlife and disease transmission can be complex and context-dependent, and disease dynamics may be determined by idiosyncratic species. Therefore, an outstanding question is how general is the finding that species with faster life histories are more probable hosts of zoonoses. Ecological knowledge on species, jointly with public health data, can provide relevant information on species that should be targeted for epidemiological surveillance or management. We investigated whether mammal species traits can be good indicators of zoonotic reservoir status in an intensified agricultural region of Argentina. We find support for a relationship between reservoir status and the pace of life syndrome, confirming that fast life histories can be a factor of zoonotic risk. Nonetheless, we observed that for certain zoonosis, reservoirs may display a slow pace of life, suggesting that idiosyncratic interactions can occur. We conclude that applying knowledge from the life history-disease relationship can contribute significantly to disease risk assessment. Such an approach may be especially valuable in the current context of environmental change and agricultural intensification.

     

How Many Species Are There? Public Understanding and Awareness of Biodiversity in Switzerland

This paper presents the results of interviews and a questionnaire study on public knowledge of the concept of biodiversity and of plant species richness in Switzerland. Despite its extensive use in science and policy making, the concept of biodiversity is not widely recognized or known to people in Switzerland. Overall, 60% of all study participants (161 grammar school pupils, 110 non-graduates, and 96 graduates in the Canton of Zurich) had never heard the term biodiversity, while the others had come across it primarily in the media. Few study participants considered their school education a relevant source of information about biodiversity. Study participants most frequently referred to the diversity of plants and animals when defining biodiversity, but also quite often believed that biodiversity had something to do with ecological concepts such as the equilibrium between all components of nature. Both young people and adults held widely inaccurate ideas of the plant species richness of communities. Particularly for Switzerland, plant species richness was strongly overestimated.

Unusual Species of Dermatophytes: Rarely Identified or New?

Dermatophytes are causing superficial mycosis in animals and humans. Depending on the geophilic, zoophilic or anthropophilic origin of the fungus but also on the immunological status of the patient, symptomatology can widely differ. Nevertheless, each species is currently associated with typical clinical manifestations, even if atypical localizations and/or clinical pictures are sometimes also reported. Diagnostic tools applied to species identification have been changing since the last two decades with the more frequent use of molecular methods currently considered nowadays as reference methods for species identification. It becomes obvious that the algorithm used for the distinction of closely related species needs to combine phenotypic and genomic methods. All these different points are discussed, and the most recent novel species causing or involved in human dermatophytosis are reported.     

Are Namibian “Fairy Circles” the Consequence of Self-Organizing Spatial Vegetation Patterning?

Causes of over-dispersed barren “fairy circles” that are often surrounded by ca. 0.5 m tall peripheral grasses in a matrix of shorter (ca. 0.2 m tall) grasses in Namibian grasslands remain mysterious. It was hypothesized that the fairy circles are the consequence of self-organizing spatial vegetation patterning arising from resource competition and facilitation. We examined the edaphic properties of fairy circles and variation in fairy circle size, density and landscape occupancy (% land surface) with edaphic properties and water availability at a local scale (<50 km) and with climate and vegetation characteristics at a regional scale. Soil moisture in the barren fairy circles declines from the center towards the periphery and is inversely correlated with soil organic carbon, possibly indicating that the peripheral grass roots access soil moisture that persists into the dry season within fairy circles. Fairy circle landscape occupancy is negatively correlated with precipitation and soil [N], consistent with fairy circles being the product of resource-competition. Regional fairy circle presence/absence is highly predictable using an empirical model that includes narrow ranges of vegetation biomass, precipitation and temperature seasonality as predictor variables, indicating that fairy circles are likely a climate-dependent emergent phenomenon. This dependence of fairy circle occurrence on climate explains why fairy circles in some locations may appear and disappear over time. Fairy circles are only over-dispersed at high landscape occupancies, indicating that inter-circle competition may determine their spacing. We conclude that fairy circles are likely to be an emergent arid-grassland phenomenon that forms as a consequence of peripheral grass resource-competition and that the consequent barren circle may provide a resource-reservoir essential for the survival of the larger peripheral grasses and provides a habitat for fossicking fauna.     

Unusual Fine Root Distributions of Two Deciduous Tree Species in Southern France: What Consequences for Modelling of Tree Root Dynamics?

The spatial distribution of fine roots of two deciduous tree species was investigated in contrasting growing conditions in southern France. Hybrid walnut trees (Juglans regia×nigra cv. NG23) and hybrid poplars (Populus euramericana cv. I214) were both cultivated with or without annual winter intercrops for 10 years on deep alluvial soils. Soil samples for measuring the fine root distribution of both trees and crops were obtained by soil coring down to 3-m depth at several distances and orientations from the tree trunk. The distribution of live fine roots from walnut and poplar trees was patchy and sometimes unexpected. In the tree-only stands, fine root profiles followed the expected pattern, as fine root density decreased with increasing depth and distance from the tree trunk. However, many fine root profiles under intercropped trees were uniform with depth, and some inverse profiles were observed. These distributions may result from a high degree of plasticity of tree root systems to sense and adapt to fluctuating and heterogeneous soil conditions. The distortion of the tree root system was more pronounced for the walnut trees that only partially explored the soil volume: in the tree-only stand, the walnut rooting pattern was very superficial, but in the intercropped stand walnut trees developed a deep and dense fine root network below the crop rooting zone. The larger poplars explored the whole available soil volume, but the intercrop significantly displaced the root density from the topsoil to layers below 1 m depth. Most tree root growth models assume a decreasing fine root density with depth and distance from the tree stem. These models would not predict correctly tree–tree and tree–understorey competition for water and nutrients in 3D heterogeneous soil conditions that prevail under low-density tree stands. To account for the integrated response of tree root systems to such transient gradients in soils, we need a dynamic model that would allow for both genotypic plasticity and transient environmental local soil conditions.