Tullia Zetto Brandmayr

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.

Ultrastructure and Comparative Morphology of Mouth-part Sensilla in Ground Beetle Larvae (Insecta, Coleoptera, Carabidae)

Abstract Labial and maxillary palps in 22 species of ground beetle larvae revealed the presence of four different types of sensilla: sensilla digitiformia, sensilla campaniformia, sensilla basiconica and sensilla chaetica. Using transmission electron microscopy techniques, the role of most of them was defined: sensilla campaniformia and sensilla chaetica are mechanoreceptors; while sensilla basiconica are chemoreceptors. Sensilla digitiformia can be both mechanoreceptors and chemoreceptors, though hygroreception may also be postulated on the basis of their abundance on the mouthparts of some hygrophilous species that depend on damp or wet patchy biotopes/seasons. The number and location of the sensory structures has been found to vary among the investigated taxa. The differences are related to the larval behavioural types, and are an adaptive response to different lifestyles, feeding habits and use of space.

Successional patterns of the insect fauna on a pig carcass in southern Italy and the role of Crematogaster scutellaris (Hymenoptera, Formicidae) as a carrion invader

The sarcosaprophagous fauna plays a key role in organic matter decomposition. Moreover, the biological, ecological and behavioral specificities of the taxa are useful to reconstruct the decay history of a corpse or carcass, often back to the lethal event. Here we report the seasonal succession of the insect fauna on a pig carcass exposed in a rural area in Calabria (southern Italy) during summer 2007 and 2008. The aim is to identify and qualitatively assess the major taxa of forensic importance in this region. The principal fly invaders were Lucilia caesar (L.), L. sericata (Meigen, 1826), Chrysomya albiceps (Wiedemann, 1819), Sarcophaga (Meigen, 1826) spp. and Amobia (Robineau‐Desvoidy, 1830) spp., Musca domestica (L.) and Muscina stabulans (Fallen, 1817). The primary beetle species collected in summer belonged to Dermestidae, Dermestes maculatus (De Geer, 1774) and Cleridae, Necrobia rufipes (De Geer, 1775). This paper also examined the ecological role of ants in the insect succession and describes the evidence of skin injuries directly inflicted by the acrobat ant Crematogaster (Acrocoelia) scutellaris (Olivier, 1791) (Hymenoptera Formicidae) while feeding on pig carrion. Ants belonging to two other species were also collected: Camponotus aethiops (Latreille, 1798) and Tetramorium semilaeve (André, 1881). Ants can invade carcasses and corpses directly, disrupting blowfly egg laying or preying on their larvae. Our data on the carrion faunal composition and role of ants as invaders should be useful for further forensic cases in Calabria (southern Italy). This is among the few reports of ants as forensically relevant species.

A case of Calliphora vicina Robineau-Desvoidy, 1830 (Diptera, Calliphoridae) breeding in a human corpse in Calabria (southern Italy)

Forensic entomology is the study of insects associated with human corpses. The most common and widely accepted application of entomological evidence in criminal investigations is to determine the post-mortem interval (PMI), i.e. the time from death to discovery of the corpse, and other circumstances of the crime scene. The insects that first colonize a human corpse usually belong to the families Calliphoridae, Sarcophagidae and Muscidae, and often are very important elements in forensic investigation. The aim of this study was to highlight the importance of evaluating forensic evidence on a regional and urban scale. To assess the climatic, geographical and environmental influences on carrion-breeding fauna, we present details of a case in Calabria (southern Italy) in February 2007. The entomological evidence consisted only of Calliphora vicina Robineau-Desvoidy, 1830. The presence of this species is related to the climatic and micro-environmental conditions in the urban habitat of Cosenza, southern Italy, and to the location and status of the cadaver.

The defensive secretion of Carabus lefebvrei Dejean 1826 pupa (Coleoptera, Carabidae): gland ultrastructure and chemical identification

This study documents the defensive function of flavored humor secreted by the abdominal glands of Carabus lefebvrei pupae. The morphology and the ultrastructure of these glands were described and the volatile compounds of glands secretion were identified by gas chromatography/mass spectrometry. The ultrastructure analysis shows an acinose complex formed by about 50 clusters. Each cluster has 20 glandular units and the unit—composed of one secretory and one canal cell lying along a duct—belongs to the class 3 cell type of Quennedey (1998). In the cytoplasm, the secretory cell contains abundant rough endoplasmatic reticula, glycogen granules, numerous mitochondria, and many well‐developed Golgi complexes producing electron‐dense secretory granules. Mitochondria are large, elongated, and often adjoining electronlucent vesicles. The kind and the origin of secretory granules varying in size and density were discussed. The chemical analysis of the gland secretion revealed the presence of a mixture of low molecular weight terpenes, ketones, aldehydes, alcohols, esters, and carboxylic acids. Monoterpenes, especially linalool, were the major products. We supposed that ketones, aldehydes, alcohols, esters, and carboxylic acids have a deterrent function against the predators and monoterpenes provide a prophylaxis function against pathogens. Microsc. Res. Tech., 2009.

Current knowledge on exocrine glands in carabid beetles: structure, function and chemical compounds.

Abstract Many exocrine products used by ground beetles are pheromones and allomones that regulate intra- and interspecific interactions and contribute to their success in terrestrial ecosystems. This mini-review attempts to unify major themes related to the exocrine glands of carabid beetles. Here we report on both glandular structures and the role of secretions in carabid adults, and that little information is available on the ecological significance of glandular secretions in pre-imaginal stages.

A preliminary investigation of insect succession on carrion in Calabria (southern Italy)

We present data from the first study of successional patterns of insect fauna in Calabria (southern Italy). The aim was to identify and qualitatively assess the major taxa of forensic importance in this region. Studies were conducted in autumn-winter 2006, summer 2007 and winter 2008 in the Botanical Garden, University of Calabria. Over 50 taxa were collected and identified. The most abundant fly species were Lucilia caesar (Linnaeus, 1758), L. sericata (Meigen, 1826), Chrysomya albiceps (Wiedemann, 1819), Calliphora vicina Robineau-Desvoidy, 1830, C. vomitoria (Linnaeus, 1758), Sarcophaga spp., Amobia sp ., Musca domestica Linnaeus, 1758, and Muscina stabulans ((Fallen). The successional patterns, relative abundance of adult sarcosaprophagous insects, carcass decay, diversity and seasonality of species are described and the taxa useful for estimating the post-mortem interval (PMI) are identified. The data of this study could be very useful for further forensic investigations in southern Italy.

Testing the predatory behaviour of Podarcis sicula (Reptilia: Lacertidae) towards aposematic and non-aposematic preys

Food preferences and the effects of prey chemical repellents in the dietary behaviour of Podarcis sicula were tested using four species of Carabid beetles as prey models. The goal of the study was to assess (i) the ability of P. sicula to recognize insect preys provided with chemical repellents and aposematic colorations under laboratory conditions, and (ii) the importance of chemical signals used by the prey model as antipredatory strategy. Preys used in this study were Brachinus sclopeta and Anchomenus dorsalis (aposematic species) and Amara anthobia and A. aenea (non-aposematic species). Aposematic species are characterized by warning color pattern and by production of chemical repellents, while non-aposematic ones do not. Amara anthobia and A. aenea were attacked with high frequency by P. sicula, Brachinus sclopeta and Anchomenus dorsalis with low frequency. Non-aposematic species were preyed more often than the aposematic ones. Brachinus sclopeta was preyed after low latency, while Amara anthobia and A. aenea after long latency. Non-aposematic species were captured and eaten without difficulty, while when B. sclopeta or A. dorsalis were captured, lizards always tossed their head and then rub the snout on the soil, probably because of the unpalatability of aposematic preys.

Morphometry of eyes, antennae and wings in three species of Siagona(Coleoptera, Carabidae)

Abstract In carabid beetles, physiological and behavioural characteristics reflect specific habitat demands and there is a strong correlation between body form and habit in species with different life style. In this study, we compared the morphometry and compound eye characteristics of three species of the genus Siagona: Siagona jenissoni, Siagona dejeani and Siagona europaea. These carabids have a stenotopic lifestyle in Mediterranean clayey soils, inhabiting the ground fissure system formed during the dry season. All species have a Mediterranean distribution and are nocturnal olfactory hunters, and are strict ant predators. For morphometric measurements, we considered body length (mm), wing length (mm), antenna length (mm), head width (mm), trochanter length (mm), number of ommatidia, eye surface area (mm2), ommatidia density (number of ommatidia/mm2 of eye surface area), head height (mm), thorax height (mm) and abdomen height (mm). The data revealed intersexual and interspecific differences. The three species differ in relative length of the antennae, density and number of ommatidia and relative trochanter length. Significant differences occurred in wing sizes, which are well developed in Siagona europaea, the only species capable of flight. When eye size is compared with other ground beetles of various lifestyles, Siagona shows pronounced “microphthalmy” an adaptation to subterranean life in clayey crevices of tropical and subtropical climates with a marked dry season.

Odour and Colour Similarity in Two Species of Gregarious Carabid Beetles (Coleoptera) from the Crati Valley, Southern Italy: A Case of Müllerian Mimicry?

ABSTRACT Bombardier beetles of the genus Brachinus (Carabidae) are disagreeable prey because they discharge irritating quinones. Brachinus beetles live in aggregations and display warning colours. Like Brachinus beetles, Anchomenus dorsalis beetles produce methylsalicylate, and present a similar colour pattern. Anchomenus dorsalis beetles are usually found within Brachinus aggregations. Our aim was to investigate the similarity of cuticular chemical profiles of these two species to test the hypothesis of interspecific chemical mimicry. We investigated the cuticular composition of A. dorsalis, B. sclopeta, and Poecilus cupreus. Poecilus cupreus, a non-aposematic carabid commonly found in Brachinus spp and Anchonemus dorsalis aggregations, was used as a control. The cuticular profiles of the three species include 48 different hydrocarbons. The cuticular hydrocarbon profiles of the three species of carabids were different, but individuals of Brachinus were chemically more similar to those of Anchomenus than to those of Poecilus; in turn, individuals of Poecilus were more similar to Anchomenus than to Brachinus. We suggest that A. dorsalis is possibly mimicking the cuticular profile of B. sclopeta as an effective antipredator strategy. Brachinus sclopeta may benefit from a reduction of individual predation risk due to an increased number of aggregated preys (dilution effect), while A. dorsalis may increase the benefit both from the dilution effect and from the greater chemical defense of B. sclopeta.