What is going on between aposematic carabide beetles? The case of Anchomenus dorsalis (Pontoppidan, 1763) and Brachinus sclopeta (Fabricius, 1792) (Coleoptera, Carabidae)

Interspecific aggregations among insects are quite common, but not among carabid beetles. Moreover, aggregations of aposematic species, and morphologically similar beetles such as Anchomenus dorsalis and Brachinus sclopeta are even rarer. Most interestingly, in these aggregations, we observed a peculiar rubbing behaviour of A. dorsalis towards B. sclopeta. In this study we aimed (i) to verify if A. dorsalis displays the rubbing behaviour towards non-aposematic species, (ii) to describe in detail and to quantify this behaviour between A. dorsalis and B. sclopeta, and (iii) to verify if previous experience of inter-specific gregariousness with the same species may exert some effects on the frequency of the rubbing display. We have investigated the qualitative and quantitative characteristics of rubbing behaviour towards aposematic and non-aposematic carabide beetle species, and then we used A. dorsalis and B. sclopeta as model species. We tested the rubbing of A. dorsalis towards B. sclopeta with either solitary A. dorsalis or in A. dorsalis coming from monospecific (A. dorsalis) or from heterospecific (A. dorsalis and B. sclopeta) aggregations. We finally tested the effectiveness of the B. sclopeta cuticular odour in eliciting rubbing from A. dorsalis by presenting olfactory dummies (special paper) either soaked with water or after it had previously been placed in a monospecific group of B. sclopeta for 15 days. First of all, we found important differences in the occurrence of rubbing behaviour towards aposematic and non-aposematic species, as A. dorsalis displayed the rubbing only towards the former. Secondly, rubbing frequency depended on the pre-test conditions (isolated, mono- or heterospecific aggregations) of the tested A. dorsalis individuals, as no rubbing occurred in individuals coming from heterospecific aggregations. The paper presentation tests demonstrated that the odour of B. sclopeta was sufficient to provoke rubbing in A. dorsalis. We conclude that aggregation in these species of carabid beetles may influence their anti-predatory defences possibly increasing the effectiveness of the aposematic (warning) signals. More work is needed to delineate in detail the evolutionary significance of this behaviour, focusing on the possibility that interspecific aggregations may not be so rare in ground beetles, and that this positive interaction could involve a larger number of species and genera, at least in wet, sun-exposed and open land habitat types

L’eterotterofauna di un’azienda agricola a conduzione biologica del versante ionico calabrese

THE HETEROPTERA OF ORGANIC MANAGED FARM ON THE IONIAN COAST OF CALABRIA The investigated farm, whose extent is about 34 hectares located on the Copanello promontory (province of Catanzaro), was subdivided into six zones differing in environmental and vegetative characteristics and technique of cultivation. Sixtyfour species of Heteroptera were collected, directly on plants, or using pitt-fall and light traps. Most Heteroptera were phytophagous species living on herbaceous plants in a zone of the farm little affected by human activities, where the technique of cultivation was limitated to a yearly tilling. Key words: bugs, vegetation, biodiversity, Southern Italy. L’azienda indagata, di circa 34 ettari, ubicata sul promontorio di Copanello (CZ) è stata suddivisa in 6 aree con caratteristiche paesaggistiche e floristico/vegetazionali differenti, caratterizzate da vari gradi di naturalità e soggette a pratiche colturali diverse. Gli esemplari di Eterotteri censiti, per un totale di 64 specie, sono stati raccolti principalmente tramite cattura diretta, o utilizzando trappole a caduta e/o trappole luminose. Gli Eterotteri, per la maggior parte, sono stati raccolti sulla vegetazione, soprattutto piante erbacee, in alcune aree dell’azienda dove l’impatto antropico è piuttosto limitato. Parole chiave: Cimici, vegetazione, biodiversità, Sud Italia

Morphometry and eye morphology in three species of Carabus (Coleoptera: Carabidae) in relation to habitat demands

Morphological features of three common European olfactory hunting carabid beetles, Carabus coriaceus mediterraneus Born, 1906, Carabus lefebvrei Dejean, 1826 and Carabus preslii neumeyeri Schaum, 1856, were compared. According to eye measurements, the three species are nocturnal and/or twilight hunters. They differ, however, in relative length of the antennae, relative surface area of the compound eyes, density of ommatidia and relative head width. These differences can be correlated with the species-specific habitat demands (light intensity, open land or shaded places). In particular, the greater lateral eye protrusion in C. lefebvrei corresponds to its tree-climbing habits, while the larger relative eye surface area and ommatidia density in C. coriaceus correspond to its choice of open habitats

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

Volume: 100Start Page: 55End Page: 14

An Unprecedented Role Reversal: Ground Beetle Larvae (Coleoptera: Carabidae) Lure Amphibians and Prey upon Them

Amphibians often feed on beetle larvae, including those of ground beetles (Carabidae). Preliminary reports have detailed an unusual trophic interaction in which, in contrast, larvae of the ground beetle Epomis prey upon juvenile and adult amphibians. While it is known that these larvae feed exclusively on amphibians, how the predator-prey encounter occurs to the advantage of the beetle larvae had been unknown to date. Using laboratory observations and controlled experiments, we recorded the feeding behavior of Epomis larvae, as well as the behavior of their amphibian prey. Here we reveal that larvae of two species of Epomis (E. circumscriptus and E. dejeani) lure their potential predator, taking advantage of the amphibian's predation behavior. The Epomis larva combines a sit-and-wait strategy with unique movements of its antennae and mandibles to draw the attention of the amphibian to the presence of a potential prey. The intensity of this enticement increases with decreasing distance between the larva and the amphibian. When the amphibian attacks, the larva almost always manages to avoid the predator's protracted tongue, exploiting the opportunity to attach itself to the amphibian's body and initiate feeding. Our findings suggest that the trophic interaction between Epomis larvae and amphibians is one of the only natural cases of obligatory predator-prey role reversal. Moreover, this interaction involves a small insect larva that successfully lures and preys on a larger vertebrate. Such role reversal is exceptional in the animal world, extending our perspective of co-evolution in the arms race between predator and prey, and suggesting that counterattack defense behavior has evolved into predator-prey role reversal

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

AbstractThe 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

Predator feeding choice on conspicuous and non-conspicuous carabid beetles: first results

Insects use various types of behaviour, chemical defences, mimetic, aposematic or cryptic appearances as anti-predatory strategies. Among insects, carabid beetles of the genus Brachinus are distasteful prey because they discharge an irritating “cloud” of quinones when threatened. These beetles live in aggregations and adopt warning (conspicuous pattern) colours and chemicals to create a template that is easily learnt by predators. Another carabid beetle, Anchomenus dorsalis, mimics the colours and cuticular profile of Brachinus and is usually found in Brachinus aggregations. In this paper we report results from laboratory observations on feeding choice of the following natural predators - Crocidura leucodon (Insectivora: Soricidae), Ocypus olens (Coleoptera: Staphylinidae) and Podarcis sicula (Reptilia: Lacertidae) - on carabid beetle species. Comparing the number of attacks of predators towards aposematic and non-aposematic prey, there was a statistically significant preference towards non-aposematic prey