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

Siagona europaea Dejean and Poecilus (Metapedius) pantanellii A. Fiori (Coleoptera: Carabidae): two clay-soil dwelling species with different uses of the space

Siagona europaea and Poecilus pantanellii are two carabid beetles strictly bound to clay soils typical of the Italian Apennines. The first exhibits a very flat body whereas the other has more "normal" proportions, suggesting a very different use of space. We tested the use of space of both species using three sets of live pitfall traps put in place at different depths in the clay soil of a Mediterranean Hedysarum pasture. Poecilus pantanellii is a very early spring breeder and more than 90% of its individuals show epigean locomotory activity. Siagona europaea's activity begins later, when the clay fissures become larger and deeper, and in the months of June and July about 80% of its population lives in the subterranean soil crevices. Morphometric measurements support these space use strategies: P. pantanellii has a wider antenna/eye angle and shorter antennae, indicating a possible visual component in prey recognition, as well as a thicker body and robust trochanters linked to "wedge pushing"; whereas S. europaea has longer antennae and a smaller antenna/eye angle suitable for olfactory-tactile prey recognition, and also has an extremely flat body and small trochanters. In the summer individuals climb up and down in the crevice system of clays searching for their specialised prey (worker ants exploring the space around their ant nests)

Are immune responses gender-related in Carabus lefebvrei (Coleoptera: Carabidae)?

The \u201clive hard, die young\u201d theory predicts the evolution of gender differences in immunocompetence, with males having a weaker immune system than females. To test this hypothesis in Carabus lefebvrei, total and basal phenoloxidase (PO) activities and lysozyme-like enzyme activity were compared among males and females of different reproductive status. The sexual dimorphism occurred only in reproductively active adults and for total and basal PO levels, while no significant differences were recorded between sexes in virgin adults. Differences were not recorded for lytic activity between sexes. Basal PO and lytic activities decreased in both males and females after mating, while the total PO value increased in males and decreased in females. Thus, resources seem to be invested to increase the humoral response in pre-reproductive phase forming a barrier against pathogens and preserving the fecundity and longevity of both sexes. Males preserve their survivorship in reproductive phase by increasing enzymatic levels in hemolymph to avoid fitness reduction due to the increased exposure to pathogen as result of mating. Females shift resources from PO and lytic activity to other physiological systems involved in reproduction in order to maximize their fitness

Beetles "in red": are the endangered flat bark beetles Cucujus cinnaberinus and C. haematodes chemically protected? (Coleoptera: Cucujidae)

Two native species of the genus Cucujus show a wide geographic distribution in Europe, Cucujus cinnaberinus (Scopoli, 1763) and C. haematodes Erichson, 1845. Although data on the distribution and ecology of these rare and endangered species are increasing, there are few reports on their biology and behaviour, and some aspects of their feeding ecology remain problematic. Our aim was to study, for the first time, the cuticular chemical profiles of these two beetles to (i) investigate the presence of chemicals potentially involved in defence by pathogens and (ii) lay the foundation for understanding the role of their bright red colour. The analysis of the cuticular profile was performed in-vivo by solid phase microextraction coupled with gas chromatography-mass spectrometry. In the cuticular profiles of the two species we identified 24 compounds belonging to different classes of molecules, i.e. hydrocarbons, aldehydes, esters, n-alkyl morpholines, and a high number of organic acids. Qualitative differences in terms of both signal intensity and detected compounds were found between the two species. As reported in other insects, the remarkable array of avoidance substances suggests a strict relationship with the bright red colour of the adults, which probably acts as an aposematic or warning signal. European Cucujus species are probably well protected against enemies because some identified chemicals, particularly fatty acids, are related to an anti-predatory strategy to fight off predators that use their sense of smell to locate their prey. Other substances found on the cuticular layer of these beetles are probably involved in an antimicrobial and antifungal function, as demonstrated in other insects living in habitats that host many pathogens

Gender-related variations in hemolymph parameters of Carabus lefebvrei (Coleoptera: Carabidae): HPLC analysis and phenoloxidase activity

We characterized the enzymatic activity of basal and total phenoloxidase and HLPC and SDS-PAGE profiles in hemolymph of Carabus lefebvrei males and females at different reproductive status. The phenoloxidase activity was activated by trypsin and inhibited by phenoloxidase activity specific inhibitor phenylthiourea. Our results demonstrated that both in males and females, there were no significant differences in the basal phenoloxidase activity between reproductive and virgin beetles, while the total phenoloxidase activity increased significantly in virgin specimens. Thus, resources seem to be invested to increase the humoral response in pre-reproductive phase forming a barrier against pathogens and preserving the fecundity and longevity of both sexes. The hemolymph DOPA-MBTH assay on polyacrilamide gel electrophoresis showed a high activity of monomeric form with an apparent molecular weight of 90 kDa and a dimer of about 170 kDa, also multimeric bands were present in both sexes. In the SDS-PAGE general protein pattern, specific bands were evident for reproductive and virgin males and females as biochemical markers of sexual difference in immunocompetence. Reproducible differences in peaks were recorded in HPLC analysis performed on virgin and reproductive males and females

The search for common anthropogenic impacts on biodiversity : a global network

We introduce an initiative to assess and compare landscape changes related to human activities on a global scale, using a single group of invertebrates. The GLOBENET programme uses common field methodology (pitfall trapping), to appraise assemblages of ground beetles (Coleoptera, Carabidae) in visually-similar land-mosaics (urban-rural gradients). Carabids were selected as the focal taxon as they are sufficiently varied (both taxonomically and ecologically), abundant and sensitive to the environment. However, work on other taxa is comparable with the GLOBENET framework. The continuum of decreasing human pressure from city centres into the surrounding countryside was selected to represent human-caused disturbance for this initial stage of GLOBENET because these gradients can be found virtually all over the world. Through the broad-scale assessment envisioned in the GLOBENET programme, we seek to separate general, repeated effects on biodiversity from those that depend on local environments or particular biotic assemblages. Based on this understanding we aim to develop simple tools and protocols for assessing ecological effects of human-caused landscape changes, which could help to sustainably manage landscapes for biodiversity and for human requirements. For instance, the response of different functional groups of carabids to these landscape changes may help guide management practices. Further GLOBENET developments and information are available at our website: http://www.helsinki.fi/science/globenet

In vivo solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS) assay to identify epicuticular profiles across task groups of Apis mellifera ligustica workers

Colony integrity and survival in honeybees is regulated by chemical signals that are actively produced by glands and synergically transmitted between the members. A number of these signals regulate the typical age-related division of labor among the worker bees performing different tasks at different ages. In this study, the analysis of the cuticular profiles in Apis mellifera ligustica Spinola, 1806 workers at various tasks (newly emerged, nurse and forager bees) was performed using in vivo solid-phase microextraction gas chromatography-mass spectrometry (SPMEGC- MS). The use of in vivo SPME shed new light on the complexity of the molecular pattern on the epicuticle of honeybees. The identified molecules are mainly hydrocarbons, saturated and unsaturated carboxylic acids, and to a less extent, esters, sterols, aldehydes, and alcohols. Their relative abundance between the three task groups was evaluated using descriptive statistics and multivariate pattern recognition analysis (i.e., principal component analysis, PCA, and linear discriminant analysis, LDA). Eleven molecules namely nonacosane, pentacosane, (Z)-12-pentacosene, 11-tricosene, 11-methylnonacosane, squalene, 13-methylheptacosane, heptacosane, heneicosane, docosane and tricosane, occur with high frequency in newly emerged, nurse, and forager bees. The compounds that contributed the most for the separation of the three task groups in the PCA were pentacosane, (Z)-12-pentacosene, 13-methylheptacosane and squalene; while for LDA, nonacosane, 11-methylnonacosane and pentacosane were the molecules that contributed most to the discrimination

Where have all the beetles gone? Long‐term study reveals carabid species decline in a nature reserve in Northern Germany

1. The drastic insect decline has received increasing attention in scientific as well as in public media. Long-term studies of insect diversity trends are still rare, even though such studies are highly important to assess extent, drivers and potential consequences of insect loss in ecosystems. 2. To gain insights into carabid diversity trends of ancient and sustainably managed woodlands, we analysed data of carabid beetles from a trapping study that has been run for 24 years in an old nature reserve of Northern Germany, the Luneburg Heath. We examined temporal changes in several diversity measures € (e.g. biomass, species richness, functional diversity and phylogenetic diversity) and tested diverse species traits as predictor variables for species occurrence. 3. In contrast to recently published long-term studies of insect diversity, we did not observe a decline in biomass, but in species richness and phylogenetic diversity in carabids at our study site. Additionally, hibernation stage predicted the occurrence probability of carabids: Species hibernating as imagines or both imagines and larvae and breeding in spring showed strongest declines. 4. We assume the detected trends to be the result of external effects such as climate change and the application of pesticides in the surrounding. Our results suggest that the drivers for the insect decline and the responses are multifaceted. This highlights the importance of long-term studies with identification of the catches to, at best, species level to support the understanding of mechanisms driving changes in insect diversity and abundance

New distributional data for the Mediterranean medicinal leech Hirudo verbana Carena, 1820 (Hirudinea, Hirudinidae) in Italy, with a note on its feeding on amphibians

Scarce data are currently available about the distribution of the Mediterranean medicinal leech Hirudo verbana in Italy, and most of the known occurrence localities are based on records collected in the nineteenth and the first half of the twentieth century, which were not confirmed in the last decades, mostly due to a lack of surveys. Accordingly, the available knowledge on the distribution of the species is far from being updated and representative, although a significant negative trend of H. verbana throughout the country is supposed. The lack of sound distribution data is a significant shortfall, which hinders the implementation of the monitoring of the species as required by the Article 17 of the “Habitats Directive” on the species of Union concern. To provide recent, validated distributional data for the Mediterranean medicinal leech in Italy to be used as baseline data for further surveys and monitoring, we present herein a set of unpublished observations collected in the last decades in peninsular Italy, Sicily, and Sardinia. Moreover, we report observation of H. verbana feeding on amphibians, a feeding habit to date poorly documented for the Mediterranean medicinal leech. Based on both published and novel data, H. verbana is characterised by a large but fragmented distribution in Italy. Therefore, dedicated monitoring programs and the collection of validated occasional observations are highly desirable to get a clearer picture of the real distribution of the species