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Northward invasion of the parasitic deer ked ( Lipoptena cervi), is there geographical variation in pupal size and development duration?
2010
SUMMARYThe deer ked (Lipoptena cervi) is a common ectoparasite of cervids. During the last decades the species has rapidly invaded in northern Europe, especially in Finland, towards the north and increased its prevalence on the moose population. Consequently, during this rapid invasion the deer ked has faced more severe climatic conditions. We studied whether pupal size (measured as pupal weight) and pupal development duration of the deer ked varies along historical invasion zones and temperature zones towards north in Finland. Moreover, we explored possible size- and gender-dependent variation in pupal development duration. We divided wild-collected pupae in respect to their origin in two …
Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community
2014
Abstract. Background: Social information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (sy…
Sexually dimorphic tegumental gland openings in Laniatores (Arachnida, Opiliones), with new data on 23 species
2009
International audience; Sexually dimorphic glands often release sexual pheromones both in vertebrates and invertebrates. Species of Laniatores (Arachnida, Opiliones) seem to depend on chemical communication but few studies have addressed this topic. In this study, we review the literature for the Phalangida and present new data for 23 species of Laniatores. In 16 taxa, we found previously undescribed sexually dimorphic glandular openings on the femur, patella, metatarsus, and tarsus of legs I and metatarsus of legs III and IV. For the other species, we provide scanning electron micrographs of previously undescribed sexually dimorphic setae and pegs located on swollen regions of the legs. We…
Field evidence of host size-dependent parasitism in two manipulative parasites.
2007
5 pages; International audience; The distribution of parasites within host natural populations has often been found to be host age-dependent. Host mortality induced by parasites is the commonest hypothesis proposed for explaining this pattern. Despite its potential importance in ecology, the parasitism intensity in relation with the host age has rarely been studied in the field. The 2 manipulative acanthocephalans, Polymorphus minutus and Pomphorhynchus laevis, use the amphipod Gammarus pulex as an intermediate host, and their infection intensity and incidence among G. pulex populations were examined by analyzing 2 large samples of hosts collected in eastern France. Both parasites had low p…
Testosterone-Mediated Effects on Fitness-Related Phenotypic Traits and Fitness
2009
International audience; The physiological and behavioral mechanisms underlying life-history trade-offs are a continued source of debate. Testosterone (T) is one physiological factor proposed to mediate the trade-off between reproduction and survival. We use phenotypic engineering and multiple laboratory and field fitness-related phenotypic traits to test the effects of elevated T between two bank vole Myodes glareolus groups: dominant and subordinate males. Males with naturally high T levels showed higher social status (laboratory dominance) and mobility (distance between capture sites) than low-T males, and the effect of T on immune response was also T group specific, suggesting that behav…
Mechanical properties of natural fiber composites produced using dynamic sheet former
2018
Composites formed from wood fibers and man-made cellulosic fibers in PLA (polylactic acid) matrix, manufactured using sheet forming technique and hot pressing, are studied. The composites have very low density (due to high porosity) and rather good elastic modulus and tensile strength. As expected, these properties for the four types of wood fiber composites studied here improve with increasing weight fraction of fibers, even if porosity is also increasing. On the contrary, for man-made cellulosic fiber composites with circular fiber cross-section, the increasing fiber weight fraction (accompanied by increasing void content) has detrimental effect on stiffness and strength. The differences …
Sourdough “ciabatta” bread enriched with powdered insects: Physicochemical, microbiological, and simulated intestinal digesta functional properties
2021
Abstract Powdered mealworm (MW) and buffalo worm (BW) larvae were used to functionalize sourdough Italian-style breads. Sourdough inoculum was started with Levilactobacillus brevis, Weissella cibaria and Leuconostoc citreum. The doughs were SBS (semolina plus powdered BW larvae and sourdough) and SMS (semolina plus powdered MW larvae and sourdough) whose pHs (4.32 and 4.21, respectively) were higher than that of control (3.81). The highest fermentation quotient (lactate/acetate molar ratio) was recorded in SMS (4.46). LAB reached viable counts of about 109 CFU g−1 in almost all doughs. Insects impacted bread VOCs with dodecanal, 2.4-dodecadienal and 2-octenal-2-butyl. SBS and SMS increased …
Synergistic reduction of a native key herbivore performance by two non-indigenous invasive algae
2019
Abstract Native generalist grazers can control the populations of non-indigenous invasive algae (NIIA). Here, it was found that the simultaneous consumption of two co-occurring NIIA, Caulerpa cylindracea and C. taxifolia var. distichophylla, hinders the grazing ability of the main Mediterranean herbivorous, the native sea urchin Paracentrotus lividus. The ingestion of any of the two NIIA alone did not produce any difference in sea urchin righting time with respect to usual algal diet. In contrast, the simultaneous consumption of both NIIA, which grow intermingled in nature and are consumed by P. lividus, retarded its righting behavior. Such result reveals substantial physiological stress in…
Helminth communities of loggerhead turtles (Caretta caretta) from Central and Western Mediterranean Sea: the importance of host's ontogeny.
2009
We investigated the factors providing structure to the helminth communities of 182 loggerhead sea turtles, Caretta caretta, collected in 6 localities from Central and Western Mediterranean. Fifteen helminth taxa (10 digeneans, 4 nematodes and 1 acanthocephalan) were identified, of which 12 were specialist to marine turtles; very low numbers of immature individuals of 3 species typical from fish or cetaceans were also found. These observations confirm the hypothesis that phylogenetic factors restrict community composition to helminth species specific to marine turtles. There were significant community dissimilarities between turtles from different localities, the overall pattern being compat…
From glacial refugia to hydrological microrefugia: Factors and processes driving the persistence of the climate relict tree Zelkova sicula
2021
Abstract With only two tiny populations, the climate relict Zelkova sicula (Sicily, Italy) is one of the rarest trees in the world. It also represents the most marginal member of genus Zelkova that was widespread in the broadleaved forests thriving in warm–temperate climates throughout Eurasia until the Last Glacial Age. Occurring at the westernmost range of the genus under typical Mediterranean climate, the micro‐topographic settings have always appeared crucial for the survival of this relict. However, the factors and processes actually involved in its persistence in the current refugia, as well as the response of similar relict trees in arid environments, are poorly understood worldwide.…