Paolo Audisio

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.

Conflict between insect conservation and public safety: the case study of a saproxylic beetle (Osmoderma eremita) in urban parks

Urban parks can harbour small populations of saproxylic insects of high conservation concern, such as Osmoderma eremita and other rare beetles. These areas often host old trees which have become very uncommon in rural areas where they are threatened by commercial forestry management procedures based on frequent tree cutting. Nevertheless, old trees of urban parks may represent a hazard for public safety and are sometimes cut by management authorities. The aim of this work was to assess the loss of reproductive sites for saproxylic beetles of the Scarabaeidae, Lucanidae and Cerambycidae, when felling plans are adopted according to a Visual Tree Assessment Procedure (VTA), in a Mediterranean urban park. On July–August 2004, 1,247 holm oaks were surveyed within the border of an urban park of Rome (Villa Borghese). The occurrence of saproxylic beetles (i.e. the presence of frass, living insects or their remains) was verified in 66 old holm oaks, 41% of which were doomed to cutting by VTA. Eleven of these trees (41% of the trees doomed to be cut) held fragments of adults and sometimes living larvae of Osmoderma eremita, and four of them (36%) were included in the felling plan. The presence of Osmodermaeremita in tree holes was more frequent in deep cavities. The presence of frass in the cavities was positively associated with tree height and a high degree of damage at the root collar and negatively with the presence of hole-nesting birds.

Surveying an endangered saproxylic beetle, Osmoderma eremita, in Mediterranean woodlands: a comparison between different capture methods

Measuring population size is riddled with difficulties for wildlife biologists and managers, and in the case of rare species, it is sometimes practically impossible to estimate abundance, whereas estimation of occupancy is possible. Furthermore, obtaining reliable population size estimates is not straightforward, as different sampling techniques can give misleading results. A mark-recapture study of the endangered saproxylic beetle Osmoderma eremita was performed in central Italy by applying four independent capture methods within a study area where 116 hollow trees were randomly selected to set traps. Detection probability and population size estimates were drawn from each of these four capture methods. There were strong differences in detection probability among methods. Despite using pheromone and beetle manipulation, capture histories were not affected by trap-happiness or trap-shyness. Population size estimates varied considerably in both abundance and precision by capture method. A number of 0.5 and 0.2 adult beetles per tree was estimated using the whole data set by closed and open population models, respectively. Pitfall trap appeared the optimal method to detect the occurrence of this species. Since in the southern part of its distribution range, a single population of O. eremita is widespread in the landscape, and includes beetles from more than one hollow tree, conservation efforts should focus not only on preserving few and isolated monumental hollow trees, but should be extended to large stands.

Habitat of an endangered saproxylic beetle, Osmoderma eremita, in Mediterranean woodlands

Abstract: The habitat of Osmoderma eremita, a European endangered beetle species restricted to tree cavities, was examined in central Italy, at the southernmost limit of its distributional range. The occurrence of adults, larvae, and fragments was investigated in 170 and 151 living hollow trees by pitfall trapping and sampling of wood mould (i.e., loose material) in the hollow, respectively. Overall, O. eremita was present in 22% of the trees, which belonged to 4 different tree species (Ostrya carpinifolia, Quercus suber, Acer obtusatum, and Quercus pubescens). The frequency of presence was higher in cavities with more than 4 L of wood mould, in cavities with dry or half-moist wood mould rather than wet wood mould, and with wood mould with low soil contamination. A comparison with northern regions indicated that the warmer macro-climatic conditions in the south make the species independent of a warm microclimate. As most of the hollow trees contain only a small amount of wood mould (<4 L), the habitat quality is generally poorer than in oak pastures studied in northern Europe.

The EU protected taxon Morimus funereus Mulsant, 1862 (Coleoptera: Cerambycidae) and its western Palaearctic allies: systematics and conservation outcomes

Morimus funereus is a large longhorn beetle included in the European Habitats Directive and in previous releases of the IUCN red list. It represents a flagship species of old-growth forest saproxylic communities in E and SE Europe. The morphologically based taxonomy of W Palaearctic Morimus is rather unstable due to high phenetic intrapopulational and geographic variability and different authors have attempted to recognise one to five different taxa of specific/subspecific rank. No previous molecular data are available for the genus Morimus. Here, for the first time, a molecular approach based on COI and ITS2 gene sequences was applied in European and Anatolian Morimus specimens. The genetic variability among Euro-Anatolian Morimus populations and the geographical structure suggest that they can not be ascribed to the currently accepted five W Palaearctic Morimus species and may actually represent a single, genetically and morphologically variable biological species (M. asper), highlighting the necessity of an extended taxonomical revision. In light of these results, a phylogeographical hypothesis of postglacial colonisation of the central Mediterranean area has been developed and the consequences of this new taxonomic arrangement regarding conservation strategies for “Morimus funereus” and allied taxa in Europe and Turkey are discussed.

A European monitoring protocol for the stag beetle, a saproxylic flagship species

Developing protocols for threatened invertebrates is often challenging, because they are not only rare but also elusive. This is the case with the stag beetle (Lucanus cervus), a protected and flagship species for the saproxylic beetle fauna in Europe. We applied a standard transect walk at a European scale (8 countries, 29 transects) to test its practicability and reliability as survey design. A total of 533 sightings were recorded throughout the sampling period, but detection probability changed as the season progressed. Considering the observed activity pattern, occupancy models showed that a short period of three consecutive weeks, between the middle of June and the first week of July, resulted in a high probability of detection (P > 0.7). As time of the peak of activity varies from year to year and between sites, we propose to extend the sampling period to five weekly surveys. Detailed information on the transect characteristics and the optimal time for surveying were analysed. The data indicate that a weekly transect at dusk provides a reliable method for monitoring this species throughout its distributional range. No correlation was found between latitude, longitude and phenology of sightings, however. However, a standard method such as the one presented, allows broadening the scale of monitoring studies, provinding data to evaluate the efficacy of conservation measures.

Interactions between larvae of the threatened saproxylic beetle Osmoderma eremita and other flower chafers in Mediterranean woodlands: implications for conservation

Interactions between larvae of one of the most charismatic and threatened saproxylic beetles, Osmoderma eremita (Scopoli, 1763), and other flower chafer species (Coleoptera: Scarabaeidae) were investigated by taking samples of wood mould, i.e. loose material inside the cavity, from 151 living hollow trees in two Mediterranean woodlands during August 2010. Multi‐species occupancy models estimate low occupancy probabilities for both O. eremita (ψ ± SE = 0.36 ± 0.13) and other flower chafer species (0.42 ± 0.06), which showed similar microhabitat requirements without competing. In cavities where larvae of both groups were present, the probability of detecting O. eremita during the sieving of 2 l of wood mould was not affected by whether larvae of other flower chafers occur in the same sample and vice versa. Unexpectedly, larvae of O. eremita were detected with a higher probability when larvae of other flower chafers occurred in the cavity. Model selection statistics strongly support that increasing the sampled volume of wood mould increases the probability of detecting larvae, especially for O. eremita. Wood mould sampling resulted in a reliable method for detecting the presence of O. eremita larvae, but further studies are needed to investigate the potential damage caused by this procedure in the fragile microhabitat of tree cavities. To preserve populations of O. eremita and other flower chafers, management actions should be focused on increasing the density of hollow trees and the volume of tree cavities by favouring the natural ageing of trees and by creating artificial habitats in living trees.

A molecular phylogeny of the cosmopolitan hyperdiverse genus Hydraena Kugelann (Coleoptera, Hydraenidae)

With almost 900 described species, Hydraena Kugelann (Hydraenidae) is one of the largest genera among Coleoptera. The subgeneric classification of Hydraena has been controversial, with 11 subgeneric names having so far been attributed to it. Some of these, Haenydra Rey and Spanglerina Perkins, have been treated as valid genera, as subgenera or as species groups. The most recent complete treatment of the genus, based on a cladistic analysis of morphological characters, recognized two major lineages, and only these were classified as subgenera: Hydraenopsis (mainly Gondwanan distribution), and Hydraena s.str. (mainly Laurasian). Here, we reconstruct the phylogeny of Hydraena using 212 species plus several outgroups and approximately 4 kb of sequence data from two nuclear (SSU and LSU) and four mitochondrial genes (cox1, rrnL, trnL and nad1). Data were aligned with two different strategies of multiple alignment (implemented in mafft and prank), and the phylogenies reconstructed using maximum likelihood and Bayesian methods. We estimated approximate ages of the main nodes using a relaxed molecular clock with Bayesian methods, and an a priori evolutionary rate of 0.01 substitutions/site/million years (Ma) plus a calibration point based on a biogeographical split. We found strong support for the monophyly of Hydraena and many of the clades recognized with morphological data. The following clades are considered as subgenera: Phothydraena Kuwert, Spanglerina Perkins, Holcohydraena Kuwert, Hydraenopsis Janssens and Hydraena s.str. The placement of three species groups, two Neotropical (H. multispina group, H. paeminosa group) and one South African/Madagascan (H. monikae group), is uncertain, and they are considered incertae sedis within Hydraena. The origin of the genus was estimated to be in the Lower Eocene, with many species complexes diversifying in the Pleistocene. Dispersal events seem to have played a key role in order to determine the current distribution of the species groups in the southern hemisphere (mainly in Hydraenopsis).

Molecular evolution of a gene cluster of serine proteases expressed in the Anopheles gambiae female reproductive tract

BackgroundGenes involved in post-mating processes of multiple mating organisms are known to evolve rapidly due to coevolution driven by sexual conflict among male-female interacting proteins. In the malaria mosquito Anopheles gambiae - a monandrous species in which sexual conflict is expected to be absent or minimal - recent data strongly suggest that proteolytic enzymes specifically expressed in the female lower reproductive tissues are involved in the processing of male products transferred to females during mating. In order to better understand the role of selective forces underlying the evolution of proteins involved in post-mating responses, we analysed a cluster of genes encoding for three serine proteases that are down-regulated after mating, two of which specifically expressed in the atrium and one in the spermatheca of A. gambiae females.ResultsThe analysis of polymorphisms and divergence of these female-expressed proteases in closely related species of the A. gambiae complex revealed a high level of replacement polymorphisms consistent with relaxed evolutionary constraints of duplicated genes, allowing to rapidly fix novel replacements to perform new or more specific functions. Adaptive evolution was detected in several codons of the 3 genes and hints of episodic selection were also found. In addition, the structural modelling of these proteases highlighted some important differences in their substrate specificity, and provided evidence that a number of sites evolving under selective pressures lie relatively close to the catalytic triad and/or on the edge of the specificity pocket, known to be involved in substrate recognition or binding. The observed patterns suggest that these proteases may interact with factors transferred by males during mating (e.g. substrates, inhibitors or pathogens) and that they may have differently evolved in independent A. gambiae lineages.ConclusionsOur results - also examined in light of constraints in the application of selection-inference methods to the closely related species of the A. gambiae complex - reveal an unexpectedly intricate evolutionary scenario. Further experimental analyses are needed to investigate the biological functions of these genes in order to better interpret their molecular evolution and to assess whether they represent possible targets for limiting the fertility of Anopheles mosquitoes in malaria vector control strategies.

Molecular re-examination of the taxonomy of the Meligethes viridescens species complex (Coleoptera: Nitidulidae)

Abstract Allozyme and RAPD analysis were performed to clarify taxonomic relationships within the Meligethes viridescens complex (Coleoptera, Nitidulidae, Meligethinae). Five populations from Central Italy belonging to three species: M. viridescens , M. czwalinai , and a new undescribed species ( M . sp. cfr. viridescens ), and one population of the morphologically well-differentiated M. aeneus were analysed. The degree of observed genetic differentiation supports separation at the specific rank of M. viridescens , M. czwalinai , and M . sp. cfr. viridescens . The species’ ecology and morphological observations based on scanning electron microscopy also supports such a taxonomic separation. The M13 RAPD primer is a diagnostic marker for distinguishing the four species. Estimates of divergence times calculated from allozymic genetic distance data suggest that the pattern of differentiation observed may be related to the palaeoclimatic changes during the Plio/Pleistocene ice cycles in southern Europe.