Search results for "systematic"
showing 10 items of 7608 documents
Role of Soil Organisms in the Maintenance of Species-Rich Seminatural Grasslands through Mowing
2009
To preserve species-rich grasslands, management practices such as mowing are often required. Mowing is known to promote aboveground conditions that help to maintain plant species richness, but whether belowground effects are important as well is not known. We hypothesized that if mowing decreases belowground carbon transfer by reducing root mass, this will reduce the abundance and activity of soil decomposers and lead to diminished nutrient availability in soil. In grasslands, this would provide a means to mitigate the negative effects of nitrogen enrichment on plant species richness. We established experimental plots on grassland with one-third of plots growing untouched, one-third mowed o…
The evolution of pedipalps and glandular hairs as predatory devices in harvestmen (Arachnida, Opiliones)
2016
Pedipalps are the most versatile appendages of arachnids. They can be equipped with spines (Amblypygi), chelae (Scorpiones), or adhesive pads (Solifugae), all of which are modifications to grasp and handle fast-moving prey. Harvestmen (Opiliones) show a high diversity of pedipalpal morphologies. Some are obviously related to prey capture, like the enlargement and heavy spination of Laniatores pedipalps. Many Dyspnoi, by contrast, exhibit thin, thread-like pedipalps that are covered with complex glandular setae (clavate setae). These extrude viscoelastic glue that is used to immobilize prey items. Comparable setae (plumose setae) have previously been found in representatives of both Eupnoi a…
Increased susceptibility to oxidative damage as a cost of accelerated somatic growth in zebra finches.
2007
1. Most animals do not grow at their maximal rate. This might appear puzzling because the early attainment of a large body size incurs several selective benefits, such as reduced risk of predation and earlier reproductive output. Several hypotheses have been suggested to explain this paradox. Among them, the cost due to high levels of oxidative stress, as the consequence of sustained metabolic activity during growth, has been put forward.
Response to: The metabolic cost of whistling is low but measurable in dolphins
2020
Costs of sound production have been investigated only sparsely in cetaceans, despite recent efforts to understand how increasing anthropogenic noise affects these animals that rely extensively on sound for communication and foraging. Theoretical estimates suggest that metabolic costs of whistling
Cuticular hydrocarbons as potential mediators of cryptic species divergence in a mutualistic ant association
2019
International audience; Upon advances in sequencing techniques, more and more morphologically identical organisms are identified as cryptic species. Often, mutualistic interactions are proposed as drivers of diversification. Species of the neotropical parabiotic ant association between Crematogaster levior and Camponotus femoratus are known for highly diverse cuticular hydrocarbon (CHC) profiles, which in insects serve as desiccation barrier but also as communication cues. In the present study, we investigated the association of the ants' CHC profiles with genotypes and morphological traits, and discovered cryptic species pairs in both genera. To assess putative niche differentiation betwee…
A morphological, biological and molecular approach reveals four cryptic species of Trissolcus Ashmead (Hymenoptera, Scelionidae), egg parasitoids of …
2019
Accurate identification of parasitoids is crucial for biological control of the invasive brown marmorated stink bug,Halyomrpha halys(Stål). A recent work by Talamas et al. (2017) revised the Palearctic fauna ofTrissolcusAshmead, egg-parasitoids of stink bugs, and treated numerous species as junior synonyms ofT. semistriatus(Nees von Esenbeck). In the present paper, we provide a detailed taxonomic history and treatment ofT. semistriatusand the species treated as its synonyms by Talamas et al. (2017) based on examination of primary types, molecular analyses and mating experiments.Trissolcus semistriatus,T. belenus(Walker),T. colemani(Crawford), andT. manteroi(Kieffer) are here recognized as v…
Cryptic taxa should have names: Reflections in the glasswort genusSalicornia(Amaranthaceae)
2012
Incongruence between morphology and molecules, i.e., genetic differentiation of lineages that are morphologically identical, or morphological variation among accessions sharing identical genotypes, has been increasingly reported and is most problematic in taxa with reduced morphologies. We here review and discuss these issues for plant taxonomy, taking Salicornia, one of the taxonomically most challenging genera of angiosperms, as a model. We argue in favour of a taxonomic system that remains as much 'workable' as possible for traditional morphology-based taxonomy, but avoids merging genetically widely divergent lineages despite their morphological similarity. Our revised classification of …
Is it really you,Orthotrichum acuminatum? Ascertaining a new case of intercontinental disjunction in mosses
2015
Intercontinental disjunct distributions are a main issue in current biogeography. Bryophytes usually have broad distribution ranges and therefore constitute an interesting subject of study in this context. During recent fieldwork in western North America and eastern Africa, we found new populations of a moss morphologically similar to Orthotrichum acuminatum. So far this species has been considered to be one of the most typical epiphytic mosses of the Mediterranean Basin. The new findings raise some puzzling questions. Do these new populations belong to cryptic species or do they belong to O. acuminatum, a species which then has a multiple-continent disjunct range? In the latter case, how c…
Integrative taxonomy sheds light on an old problem: theUlota crispacomplex (Orthotrichaceae, Musci)
2016
The combined use of morphological and molecular analyses has been proven to be useful in resolving taxonomic complexes with hidden diversity. In bryology, however, integrative taxonomy has rarely been employed to revisit relevant old, unresolved problems. One of these classical controversies is whether the Ulota crispa complex comprises one or three species. To elucidate this, an exhaustive morphological revision, based on numerous herbarium and fresh specimens from most of the Holarctic areas in which U. crispa has been reported, and molecular analyses, using one nuclear (ITS2) and three plastid (trnG, trnL-trnF, atpB-rbcL) loci on a selection of representative specimens, have been perform…
Morphological traits predict host-tree specialization in wood-inhabiting fungal communities
2020
Tree species is one of the most important determinants of wood-inhabiting fungal community composition, yet its relationship with fungal reproductive and dispersal traits remains poorly understood. We studied fungal communities (total of 657 species) inhabiting broadleaved and coniferous dead wood (total of 192 logs) in 12 semi-natural boreal forests. We utilized a trait-based hierarchical joint species distribution model to examine how the relationship between dead wood quality and species occurrence correlates with reproductive and dispersal morphological traits. Broadleaved trees had higher species richness than conifers, due to discomycetoids and pyrenomycetoids specializing in them. Re…