Achille Casale

Forty years of carabid beetle research in Europe – from taxonomy, biology, ecology and population studies to bioindication, habitat assessment and conservation

Abstract ‘Carabidologists do it all’ (Niemelä 1996a) is a phrase with which most European carabidologists are familiar. Indeed, during the last half a century, professional and amateur entomologists have contributed enormously to our understanding of the basic biology of carabid beetles. The success of the field is in no small part due to regular European Carabidologists’ Meetings, which started in 1969 in Wijster, the Netherlands, with the 14th meeting again held in the Netherlands in 2009, celebrating the 40th anniversary of the first meeting and 50 years of long-term research in the Dwingelderveld. This paper offers a subjective summary of some of the major developments in carabidology since the 1960s. Taxonomy of the family Carabidae is now reasonably established, and the application of modern taxonomic tools has brought up several surprises like elsewhere in the animal kingdom. Progress has been made on the ultimate and proximate factors of seasonality and timing of reproduction, which only exceptionally show non-seasonality. Triggers can be linked to evolutionary events and plausibly explained by the “taxon cycle” theory. Fairly little is still known about certain feeding preferences, including granivory and ants, as well as unique life history strategies, such as ectoparasitism and predation on higher taxa. The study of carabids has been instrumental in developing metapopulation theory (even if it was termed differently). Dispersal is one of the areas intensively studied, and results show an intricate interaction between walking and flying as the major mechanisms. The ecological study of carabids is still hampered by some unresolved questions about sampling and data evaluation. It is recognised that knowledge is uneven, especially concerning larvae and species in tropical areas. By their abundance and wide distribution, carabid beetles can be useful in population studies, bioindication, conservation biology and landscape ecology. Indeed, 40 years of carabidological research have provided so much data and insights, that among insects - and arguably most other terrestrial organisms - carabid beetles are one of the most worthwhile model groups for biological studies.

Phylogenetic relationships of Western Mediterranean subterranean Trechini groundbeetles (Coleoptera: Carabidae)

Faille, A., Casale, A. & Ribera, I. (2010). Phylogenetic relationships of Western Mediterranean subterranean Trechini groundbeetles (Coleoptera: Carabidae). —Zoologica Scripta, 40, 282–295.

A molecular phylogeny of Alpine subterranean Trechini (Coleoptera: Carabidae)

BackgroundThe Alpine region harbours one of the most diverse subterranean faunas in the world, with many species showing extreme morphological modifications. The ground beetles of tribe Trechini (Coleoptera, Carabidae) are among the best studied and widespread groups with abundance of troglobionts, but their origin and evolution is largely unknown.ResultsWe sequenced 3.4 Kb of mitochondrial (cox1, rrnL, trnL, nad1) and nuclear (SSU, LSU) genes of 207 specimens of 173 mostly Alpine species, including examples of all subterranean genera but two plus a representation of epigean taxa. We applied Bayesian methods and maximum likelihood to reconstruct the topology and to estimate divergence times using a priori rates obtained for a related ground beetle genus. We found three main clades of late Eocene-early Oligocene origin: (1) the genus Doderotrechus and relatives; (2) the genus Trechus sensu lato, with most anisotopic subterranean genera, including the Pyrenean lineage and taxa from the Dinaric Alps; and (3) the genus Duvalius sensu lato, diversifying during the late Miocene and including all subterranean isotopic taxa. Most of the subterranean genera had an independent origin and were related to epigean taxa of the same geographical area, but there were three large monophyletic clades of exclusively subterranean species: the Pyrenean lineage, a lineage including subterranean taxa from the eastern Alps and the Dinarides, and the genus Anophthalmus from the northeastern Alps. Many lineages have developed similar phenotypes independently, showing extensive morphological convergence or parallelism.ConclusionsThe Alpine Trechini do not form a homogeneous fauna, in contrast with the Pyrenees, and show a complex scenario of multiple colonisations of the subterranean environment at different geological periods and through different processes. Examples go from populations of an epigean widespread species going underground with little morphological modifications to ancient, geographically widespread lineages of exclusively subterranean species likely to have diversified once fully adapted to the subterranean environment.

Hotspots of biodiversity and conservation priorities: a methodological approach

This is a methodological paper aimed at comparing methods to assess regional biodiversity. In more detail we compared the effectiveness of hotspots of species richness, of rarity and complementarity in evaluating local animal diversity. Species distributions were sampled over a 10×10 km UTM grid across the Italian territory. We considered 471 species of zygaenids, butterflies, carabines, amphibians and reptiles. Hotspots were analysed at national and regional levels and considered taxa either all together, or separately. To test the predictive value of complementarity analysis, we initially excluded zygaenids. At national level, of 3218 10×10 km UTM quadrats sampled, 161 (5% of total) had highest species richness. Islands included only 1 hotspot (Sicily). Sixty‐eight species (14.4%) were not represented. They were mainly endemic (65%), insular (73.5%), or rare (25%). Working taxon by taxon, hotspots numbered 433. Only 85 (19.6%) were hotspots contemporaneously for two taxa and only 9 were hotspots for 3 taxa. Missing species were fundamentally insular species. The regional‐level approach generated 467 hotspots. Eleven species were not represented (2.3%). They had marginal distributions, or were insular endemites. Hotspots of rarity numbered 235 and 10 species were not included. Results demonstrated that hotspots are poor predictors of overall biodiversity. The complementarity method identified 67 quadrats. By definition, these quadrats accounted for all species investigated. They failed, however, to predict the occurrence of three zygaenids. As expected, complementarity provided better results than hotspots analysis. Combining the two methods assures that areas having the highest biodiversity are identified, even working with incomplete databases. Regional or rarity hotspots should generally be preferred to hotspots of species richness.

Review: The Dark Side of Relict Species Biology: Cave Animals as Ancient Lineages

Due to their fascinating biology and phenomena belonging to the realm of scientific curiosity, cave animals have been objects of study for zoologists for numerous decades. This chapter not only focuses on the extremes (e.g., absence of eyes, specialization to extreme environments), but also serves as an introduction to understand the geographic distribution patterns and history of these highly diverse ecological groups with their relict characteristics. After an introduction to the subterranean environment in Sect. 1, we briefly review the biology and ecology of cave animals with their regressive and progressive evolutionary tendencies in order to understand the innate reasons for restricted distribution patterns (Sect. 2). In Sect. 3, we summarize the main aspects of our knowledge regarding the distribution of these species, especially in the Holarctic; and finally in Sect. 4, we highlight the relict characteristics of cave animal distribution and the ancient phylogenetic splits between cave and surface lineages.

Biochemical systematics and phylogeography of the percus strictus subspecies (coleoptera, carabidae), endemic to Sardinia

Abstract Allozymic variation at 14 loci was studied in six Sardinian populations of the carabid beetle Percus strictus. These populations represent the four subspecies of P. strictus recognised on morphological grounds in the island. Clustering and multivariate analyses were able to discriminate different subspecies, supporting the morphological evidence. Genetic distance data and .P‐sta‐tistics analysis indicated a certain degree of isolation among subspecies, but not high enough to propose the splitting of the polytypic F‐strictus into different species. From molecular clock and geological data, it is inferred that the major differentiation events were due to vicariance and took place at the beginning of the Pliocene, in concomitance with sea introgressions that subdivided the island into different blocks roughly corresponding to the present ranges of the different subspecies.

Hypogean carabid beetles as indicators of global warming

Climate change has been shown to impact the geographical and altitudinal distribution of animals and plants, and to especially affect range-restricted polar and mountaintop species. However, little is known about the impact on the relict lineages of cave animals. Ground beetles (carabids) show a wide variety of evolutionary pathways, from soil-surface (epigean) predatory habits to life in caves and in other subterranean (hypogean) compartments. We reconstructed an unprecedented set of species/time accumulation curves of the largest carabid genera in Europe, selected by their degree of ?underground? adaptation, from true epigean predators to eyeless highly specialized hypogean beetles. The data show that in recent periods an unexpectedly large number of new cave species were found lying in well established European hotspots; the first peak of new species, especially in the most evolved underground taxa, occurred in the 1920?30s and a second burst after the 70s. Temperature data show large warming rates in both periods, suggesting that the temperature increase in the past century might have induced cave species to expand their habitats into large well-aired cavities and superficial underground compartments, where they can be easily sampled. An alternative hypothesis, based on increased sampling intensity, is less supported by available datasets.

Italian natural history museums on the verge of collapse

Abstract The Italian natural history museums are facing a critical situation, due to the progressive loss of scientific relevance, decreasing economic investments, and scarcity of personnel. This is extremely alarming, especially for ensuring the long-term preservation of the precious collections they host. Moreover, a commitment in fieldwork to increase scientific collections and concurrent taxonomic research are rarely considered priorities, while most of the activities are addressed to public events with political payoffs, such as exhibits, didactic meetings, expositions, and talks. This is possibly due to the absence of a national museum that would have better steered research activities and overall concepts for collection management. We here propose that Italian natural history museums collaborate to instate a “metamuseum”, by establishing a reciprocal interaction network aimed at sharing budgetary and technical resources, which would assure better coordination of common long-term goals and scientific activities.

The third instar larva of Speomolops sardous Patrizi, 1955, a cave-dwelling molopine beetle endemic to Eastern Sardinia, with notes on its habitat (Coleoptera, Carabidae)

Abstract While the larval morphology and peculiar behaviour of several epigean species of molopine beetles (Carabidae: Pterostichini: Molopina) have been known for several years, we know very little about the specialized subterranean species of some genera endemic to the Tyrrhenian area, including Molopidius Jeannel, 1942, Oscadytes Lagar, 1975, Henrotius Jeannel, 1953, Zariqueya Jeannel, 1924, and Speomolops Patrizi, 1955. In this paper, we describe and illustrate the third instar larva of Speomolops sardous Patrizi, 1955, a specialized troglobitic beetle endemic to eastern Sardinia. Diagnostic features include the lack of stemmata; the presence of a longitudinal, membranous furrow along the dorsal surface of the mandibles; a small retinaculum; and a uniquely shaped seta FR8. We compare the morphology of this larva with some of its close relatives in the genera Molops Bonelli, 1810, Tanythrix Schaum, 1858, and Typhlochoromus Moczarsky, 1913. Some data are also given about the habitat and bionomics of the larval stages of Speomolops sardous, which show an obligate, fossorial behaviour into sandy soils in deep zones of large, periodically flooded subterranean systems.

Carabus of Subgenus Cathoplius C.G. Thomson, 1875, with description of their life-way, life-cycle and pre-imaginal morphology (Coleoptera: Carabidae)

According to current taxonomy, Subgenus Cathoplius C.G. Thomson, 1875, within the Genus Carabus Linnaeus, 1758 (in the broad sense), includes two species: C. (Cathoplius) asperatus (Dejean, 1826), monotypic with a northern distribution, and the southern polytypic substitutive species C. (Cathoplius) stenocephalus Lucas, 1866. The authors describe the life-way, life-cycle and pre-imaginal characters of the taxa currently ascribed to Subgenus Cathoplius, with details never provided before. Cathoplius are ground beetles adapted to live in arid environments and extreme habitats such as sub-desert areas. All of them are strictly helicophagous, both during the pre-imaginal stages and as adults, and are localized in a narrow fringe along the Atlantic coast of northwestern Africa. Several data and observations on the eco-ethology of the different taxa, obtained both in field and in laboratory, are reported. The life-cycle of Cathoplius belongs to the winter breeding type, with an extremely high fecundity rate concentrated in a very short period of time, that has no similarity to any other Carabus species. Eggs, larvae and pupae of the different species and subspecies of Cathoplius are described and illustrated. Larval characters clearly place Subgenus Cathoplius into the lineage of Neocarabi, confirming it as a monophyletic and homogeneous assemblage. Hybridization trials between some taxa led to a reduced survival rate of the progeny, thus confirming their specific or subspecific differentiation as proposed by classical taxonomy. Furthermore, hybridization results suggest that C. (Cathoplius) stenocephalus aliai could be considered as a distinct species. Notes about the origin, biogeography and phylogeny of Cathoplius are also provided.