150 research outputs found
New Species in the Old World: Europe as a Frontier in Biodiversity Exploration, a Test Bed for 21st Century Taxonomy
The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late
Versatile Aggressive Mimicry of Cicadas by an Australian Predatory Katydid
Background: In aggressive mimicry, a predator or parasite imitates a signal of another species in order to exploit the recipient of the signal. Some of the most remarkable examples of aggressive mimicry involve exploitation of a complex signal-response system by an unrelated predator species. Methodology/Principal Findings: We have found that predatory Chlorobalius leucoviridis katydids (Orthoptera: Tettigoniidae) can attract male cicadas (Hemiptera: Cicadidae) by imitating the species-specific wing-flick replies of sexually receptive female cicadas. This aggressive mimicry is accomplished both acoustically, with tegminal clicks, and visually, with synchronized body jerks. Remarkably, the katydids respond effectively to a variety of complex, species-specific Cicadettini songs, including songs of many cicada species that the predator has never encountered. Conclusions/Significance: We propose that the versatility of aggressive mimicry in C. leucoviridis is accomplished by exploiting general design elements common to the songs of many acoustically signaling insects that use duets in pairformation. Consideration of the mechanism of versatile mimicry in C. leucoviridis may illuminate processes driving the evolution of insect acoustic signals, which play a central role in reproductive isolation of populations and the formation of species
Listening carefully: increased perceptual acuity for species discrimination in multispecies signalling assemblages
Communication is a fundamental component of evolutionary change because of its role in mate choice and sexual selection. Acoustic signals are a vital element of animal communication and sympatric species may use private frequency bands to facilitate intraspeciïŹc communication and identiïŹcation of conspeciïŹcs (acoustic communication hypothesis, ACH). If so, animals should show increasing rates of misclassiïŹcation with increasing overlap in frequency between their own calls and those used by sympatric heterospeciïŹcs. We tested this on the echolocation of the horseshoe bat, Rhinolophus capensis, using a classical habituation-dishabituation experiment in which we exposed R. capensis from two phonetic populations to echolocation calls of sympatric and allopatric horseshoe bat species (Rhinolophus clivosus and Rhinolophus damarensis) and different phonetic populations of R. capensis. As predicted by the ACH, R. capensis from both test populations were able to discriminate between their own calls and calls of the respective sympatric horseshoe bat species. However, only bats from one test population were able to discriminate between calls of allopatric heterospeciïŹcs and their own population when both were using the same frequency. The local acoustic signalling assemblages (ensemble of signals from sympatric conspeciïŹcs and heterospeciïŹcs) of the two populations differed in complexity as a result of contact with other phonetic populations and sympatric heterospeciïŹcs. We therefore propose that a
hierarchy of discrimination ability has evolved within the same species. Frequency alone may be sufïŹcient to assess species membership in relatively simple acoustic assemblages but the ability to use additional acoustic cues may have evolved in more complex acoustic assemblages to circumvent misidentiïŹcations as a result of the use of overlapping signals. When the acoustic signal design is under strong constraints as a result of dual functions and the available acoustic space is limited because of co-occurring species, species discrimination is mediated through improved sensory acuity in the receiver
Sound Signalling in Orthoptera
The sounds produced by orthopteran insects are very diverse. They are widely studied for the insight they give into acoustic behaviour and the biophysical aspects of sound production and hearing, as well as the transduction of sound to neural signals in the ear and the subsequent processing of information in the central nervous system. The study of sound signalling is a multidisciplinary area of research, with a strong physiological contribution. This review considers recent research in physiology and the links with related areas of acoustic work on the Orthoptera
The European unionâs 2010 target: Putting rare species in focus
P. 167-185The European Union has adopted the ambitious target of halting the loss of biodiversity by
2010. Several indicators have been proposed to assess progress towards the 2010 target, two
of them addressing directly the issue of species decline. In Europe, the Fauna Europaea
database gives an insight into the patterns of distribution of a total dataset of 130,000 terrestrial
and freshwater species without taxonomic bias, and provide a unique opportunity
to assess the feasibility of the 2010 target. It shows that the vast majority of European species
are rare, in the sense that they have a restricted range. Considering this, the paper discusses
whether the 2010 target indicators really cover the species most at risk of extinction.
The analysis of a list of 62 globally extinct European taxa shows that most contemporary
extinctions have affected narrow-range taxa or taxa with strict ecological requirements.
Indeed, most European species listed as threatened in the IUCN Red List are narrow-range
species. Conversely, there are as many wide-range species as narrow-range endemics in
the list of protected species in Europe (Bird and Habitat Directives). The subset of
biodiversity captured by the 2010 target indicators should be representative of the whole
biodiversity in terms of patterns of distribution and abundance. Indicators should not overlook
a core characteristic of biodiversity, i.e. the large number of narrow-range species and
their intrinsic vulnerability. With ill-selected indicator species, the extinction of narrowrange
endemics would go unnoticedS
Amyloids - A functional coat for microorganisms
Amyloids are filamentous protein structures ~10 nm wide and 0.1â10 ”m long that share a structural motif, the cross-ÎČ structure. These fibrils are usually associated with degenerative diseases in mammals. However, recent research has shown that these proteins are also expressed on bacterial and fungal cell surfaces. Microbial amyloids are important in mediating mechanical invasion of abiotic and biotic substrates. In animal hosts, evidence indicates that these protein structures also contribute to colonization by activating host proteases that are involved in haemostasis, inflammation and remodelling of the extracellular matrix. Activation of proteases by amyloids is also implicated in modulating blood coagulation, resulting in potentially life-threatening complications.
- âŠ