Lucanus Cervus Research Articles

Monitoring of saproxylic beetles in Croatia: following the path of the stag beetle

As a member of the European Union, Croatia is obliged to report on the conservation status of 220 animal non-bird species listed in the annexes of the Habitats Directive (92/43/EEC), for which purpose a monitoring system is being established. Concerning saproxylic beetles, seven species present in its territory have to be monitored: Lucanus cervus, Cerambyx cerdo, Morimus funereus, Rhysodes sulcatus, Cucujus cinnaberinus, Rosalia alpina and Osmoderma eremita complex. Out of these species, a monitoring programme has only been established for Lucanus cervus, which partially includes participation of non-experts. In 2015 and 2016, a public campaign was organised in order to collect observations of Lucanus cervus and two other saproxylic beetles that are easily recognisable by the public: Morimus funereus and Rosalia alpina. Data gathered through this campaign serve as an addition to the mapping activities and monitoring of the species’ range. So far, more than 650 citizen observations have been collected, providing data on species presence in 216 10×10 km2 grid cells intended for reporting on the species’ range. Besides the public campaign, since 2014, public institutions for managing nature protected values have been involved in population monitoring for which they received education through several workshops. Altogether, 21 sites have been included in the monitoring of the stag beetle so far. Data collected for Lucanus cervus on standard transects, by tree and ground pitfall traps and tree trunk surveys at night will be discussed. To the present time, eight public institutions have been involved in stag beetle population monitoring and the number has been continuously increasing.

Latitudinal cline in weapon allometry and phenology of the European stag beetle

Animal body size commonly exhibits a remarkable variation in response to environmental conditions. Latitude, when correlated with temperature, rainfall and seasonality, represents one of the main determinants of variation in body size, as well as in allometry. It has long been recognised that populations of larger body size are found in colder environments (Bergmann’s Rule), a cornerstone of evolutionary ecology. However, the way in which latitude might influence investment in exaggerated weapons of animals has received little attention. The European stag beetle Lucanus cervus (Linnaeus, 1758) is the focus of this study. Males of this species exhibit exaggerated mandibles, mainly used as weapons during intra-sexual conflicts. Five populations ranging from northern Italy to the southern limit of the distribution of L. cervus were analysed. Combining morphological and phenological data, latitudinal variation in body size, weapon investment and activity period of the adults were evaluated. The analysis of the allometry of mandibles strongly supported the presence of two male morphs. Large males (major morph) invest significantly more in weapons compared to males of the minor morph. Consistent with Bergmann’s Rule, these results confirmed that the stag beetle body size increased at higher latitudes (N) and that this increase in size triggers an arms race which leads to further exaggeration of male weapons which is particularly evident in major males. In this morph, the mandible allometric coefficient line was steeper for the northern populations. The activity period also varied with latitude, beginning later at lower latitudes. Characterisation and comparison of adult phenologies provide valuable data to be used in the design of monitoring programmes for this threatened species and are important for modelling the species responses to climate change.

Can we successfully monitor a population density decline of elusive invertebrates? A statistical power analysis on Lucanus cervus

Can we successfully monitor a population density decline of elusive invertebrates? A statistical power analysis on Lucanus cervus

Insights into the ecology, genetics and distribution of Lucanus elaphus Fabricius (Coleoptera: Lucanidae), North America's giant stag beetle

Abstract Little is known about the biology or conservation status of Lucanus elaphus Fabricius in North America despite well‐documented declines of a related species, Lucanus cervus (L.), in Europe. This study provides information critical to developing conservation plans for L. elaphus including the species’ larval substrate requirements, genetic data and range‐wide estimates of habitat suitability. In Mississippi floodplain forests, larval L. elaphus were recovered from a wide range of log sizes and rot types and were either found tunnelling within the wood or feeding beneath logs at the soil–wood interface. The species appears to require 1–2 years to complete development, exhibits a 1:1 sex ratio and is parasitised by Zelia vertebrata (Say) (Diptera: Tachinidae). Flight intercept traps placed at three heights at both the edge and interior of hardwood‐dominated forests in Georgia yielded six adult male L. elaphus, all of which were captured in traps placed at 15 m on the forest edge. Because L. elaphus larvae are morphologically indistinguishable from related species, DNA sequence data from the mitochondrial cytochrome oxidase I gene were generated to facilitate molecular identification. Genetic data revealed modest intra‐specific variation, with up to 1.3% sequence divergence among haplotypes sampled from the same forest. Based on assembled occurrence records, ecological niche models suggest that environmental conditions are suitable for L. elaphus across much of the southeastern United States, provided that adequate lowland forest cover and dead wood substrates are available.

Effects of trap baits and height on stag beetle and flower chafer monitoring: ecological and conservation implications

The implementation of conservation actions requires a reliable assessment of presence and/or abundance of targeted species. This is particularly difficult for rare and elusive species. In this study the use of bottle traps and the effects of two potential baits in relation to height in the trees were tested to detect presence and assess abundance of stag beetles (Lucanidae) and flower chafers (Scarabaeidae, Cetoniinae), an important component of forest biodiversity. The study was carried out in a flood-plain forest of northern Italy. Forty-eight handcrafted traps were assigned to two height categories (1.5–2 m and 10–20 m) and three kinds of bait: (i) red wine, white wine and sugar, (ii) red wine, beer and mashed banana, (iii) no bait, as control. Fieldwork lasted 8 weeks, with 32 surveys, from May to July. Overall, we recorded 399 captures of the following species: Dorcus parallelipipedus, Lucanus cervus, Cetonia aurata, Protaetia speciosissima, P.affinis, P. morio and P. cuprea. Traps baited with red wine, white wine and sugar showed the highest detection probabilities for all the species. A clear preference for the canopy layer (traps between 10 and 20 m high) was shown by all species except for D. parallelipipedus which was mostly captured between 1.5 and 2 m of height. The study period was long enough to improve ecological knowledge on species phenology, but not enough to include the whole phenology for all of them. The method allowed the assessment of population size only for flower chafers as the number of stag beetles captures was too low.

Shape variation of mandible and head in Lucanus cervus (Coleoptera: Lucanidae): a comparison of morphometric approaches

Shape variation of mandible and head in Lucanus cervus (Coleoptera: Lucanidae): a comparison of morphometric approaches

Research paper. Data on the Beetle Fauna (Insecta: Coleoptera) in “Frumoasa” Site of Community Importance (ROSCI0085, Romania) and Its Surroundings

Abstract 222 coleopteran species and subspecies, belonging to 25 families, were found between 2014-2015 during faunal sampling in “Frumoasa” Site and its surroundings. Out of them, Carabus variolosus Fabricius, Lucanus cervus (Linnaeus), Osmoderma eremita (Scopoli), Cerambyx cerdo (Linnaeus), Morimus funereus Mulsant and Rosalia alpina (Linnaeus) are species of community importance, included in the Annex II of the Habitat Directive. In addition, several endemic or rare species/subspecies were collected: Carabus gigas gigas Creutzer, C. planicollis planicollis Küster, C. obsoletus carpathicus Palliardi, Poecilus szepligetii szepligetii (Csiki), Pterostichus findelii (Dejean) and P. pilosus wellensii (Drapiez).

Photographic identification method (PIM) using natural body marks: A simple tool to make a long story short

Individual marking allows researchers to collect important data using Mark-recapture method. Photographic Identification Method (PIM) has obtained favorable opinions, being effective and less intrusive with respect to traditional marking procedures. Here, we developed and tested the efficacy of a software-aided PIM based on different characteristics, which act as natural marks. Target species were the northern spectacled salamander (Salamandrina perspicillata, Amphibia: Urodela) and the stag beetle (Lucanus cervus, Coleoptera: Lucanidae). We considered as natural mark the ventral pattern of S. perspicillata and, for the first time in L. cervus, the presence/number of small denticles on male mandibles. We selected 4 independent characteristics, each one with several states, for each species. We asked participants, with different degree of familiarity with the species, to identify recaptured individuals through manual PIM. To assess the advantages of the software, we compared the time spent by experts of the species to identify an individual through manual PIM and software-aided PIM. We further compared our semi-automated method with a fully automated one. The software efficiency was calculated by increasing the number of characteristics used to filter individuals from the database (from 1 to 4). The chosen characteristics proved their reliability for individual identification and can be used as natural marks. The proposed software-aided PIM shorten the identification time, does not led to mismatching errors and proved its efficacy regardless of the taxa/characteristic used. Thus, this tool can be consider a more practical alternative to conventional marking techniques, in particular for sensitive and threatened species that need quick and effective monitoring programs carried out with non-invasive sampling methods.

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

Abstract 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.

Citizen science data as an efficient tool for mapping protected saproxylic beetles

Global change imposes rapid assessments to obtain reliable and updated distribution data to implement conservation measures. This task is undoubtedly unaffordable for numerous invertebrate species, both in terms of time and economic resources, because they are often elusive, detectable life stages are present for a restricted time and ecological data are scarce. Citizen science might be able to provide a large number of records and these data might facilitate the evaluation of extinction risks. Large saproxylic beetles represent an ideal group to assess the potential of citizen science to map distributions on a large scale geographic distribution. The data presented were collected during a citizen science program developed within the LIFE Project “Monitoring of Insects with Public Participation”, which used a website and a mobile app to involve citizens. We selected three pan European species protected under the Habitats Directive: Lucanus cervus, Morimus asper/funereus and Rosalia alpina, and we compared the data gathered by the citizen science project with distributional data from the official national species inventory. For all species we found a low overlap of occupied cells and the integration of the two datasets resulted in an increase in the distributional ranges of up to one third. Furthermore, taking into account the time frame of data collection, we found that the extent of occurrence obtained in 10years of records present in the national dataset was comparable to data collected in only two years of the citizen science data project. Similar results were obtained for the estimates of spatial parameters for the IUCN Red List assessment. Our study shows the potential and the efficacy of citizen science projects as rapid tools to provide reliable distributional data for neglected species of high conservation priority.

When morphological identification meets genetic data: the case ofLucanus cervusandL. tetraodon(Coleoptera, Lucanidae)

The European stag beetle Lucanus cervus, widely distributed across Europe and in some Near East countries, is one of the best known coleopteran species listed in the European Habitats Directive 92/43/EEC and it is considered a flagship species for conservation of saproxylic fauna. Lucanus tetraodon is a closely related species whose geographical distribution is still poorly known and debated. The two species have a sympatric occurrence in central Italy, and in some localities of these areas, many individuals show a mosaic of morphological traits that makes species assignment nearly impossible. We used both mitochondrial and nuclear markers to analyse these specimens. The mitochondrial results evidenced that the two species represent well-defined genetic entities with mitochondrial DNA introgression. This pattern could be the result of either hybridization or of a convergence of morphological characters under local selective pressures in areas of sympatric occurrence. The nuclear marker was polymorphic across the two species and therefore did not reveal hybridization, even if many are the supports to this phenomenon. The most plausible explanation for this genetic pattern is a very recent divergence of the two species which share a common origin and thus a common wg genotype.

The presence of a mycangium in European Sinodendron cylindricum (Coleoptera: Lucanidae) and the associated yeast symbionts.

Part of the exoskeleton of some wood-inhabiting insects is modified to form a mycangium, which is a specialized organ used to convey fungal spores or yeasts to their offspring. Although most stag beetles (Coleoptera: Lucanidae) are known to have female-specific mycangia and associated yeast symbionts, the evolutionary origin of the mycangium in this group remains unresolved. Here, we report the presence of a mycangium and associated yeast symbionts in the European horned stag beetle Sinodendron cylindricum (L.), which belongs to an ancestral clade of the Lucanidae. The mycangium of S. cylindricum is shown to be female-specific and have the same developmental origin as that of other stag beetles. A total of five yeast strains were isolated from adult mycangia and larval gut of S. cylindricum. Of these, we suggest that SICYAM1 is an undescribed yeast with taxonomic novelty, and have identified SICYLG3 as the xylose-fermenting yeast Scheffersomyces insectosa using nuclear ribosomal RNA and ITS sequences. The remaining three yeast strains, SICYAM2, SICYLG1, and SICYLG2, were assigned to the genus Sugiyamaella. Yeast density in the adult mycangium was lower than that of the more evolutionarily advanced stag beetles, the European Lucanus cervus (L.) and Dorcus parallelipipedus (L.), which were also examined in this study. No living yeasts were isolated from the adult guts. However, a third instar larva of S. cylindricum harbored 104–106 living yeasts in each gut region, which suggests that gut yeasts play an important role in these wood-feeding larvae.

Exaggerated allometric structures in relation to demographic and ecological parameters in Lucanus cervus (Coleoptera: Lucanidae).

Enlarged weapons and ornamental traits under sexual selection often show a positive allometric relationship with the overall body size. The present study explores the allometry of mandibles and their supporting structure, the head, in males of the European stag beetle, Lucanus cervus. This species shows a remarkable dimorphism in mandible shape and size that are used by males in intraspecific combats. Stag beetles were captured, measured, weighed, and released in the framework of a capture-mark-recapture study. The relationship of mandible length (ML) and head width in respect to the overall body size was described by a segmented regression model. A linear relationship was detected between ML and head width. The scaling relationships for both ML and head width identified the same switchpoint, highlighting the advantages of using combined results of weapons and their supporting structures in such analysis. These results led to a more consistent distinction of males in two morphologies: minor and major. The survival probability of individuals was dependent on the morphological class and was higher for minor males than for major. Elytron length and body mass of the individuals did not show any significant variation during the season. Differences in predatory pressure were detected between morphs by the collection and analysis of body fragments due to the predatory activity of corvids. Morphological differences and shift in demographic and ecological parameters between the two classes suggested that selection continues to favor intrasexual dimorphism in this species throughout a trade-off mechanism between costs and benefits of carrying exaggerated traits.

Monitoring presence, abundance and survival probability of the stag beetle, Lucanus cervus, using visual and odour-based capture methods: implications for conservation

A capture-mark-recapture study on the threatened saproxylic beetle Lucanus cervus was carried out in a chestnut (Castanea sativa) woodland located in northern Italy, using visual encounter surveys (VES) as well as aerial flight interception traps and pitfall traps (PT), both of which were baited with different odour lures. In total, 111 males and 25 females were captured, and VES was by far the most efficient method, accounting for 93 % of first captures, and 95 % of all captures. Stag beetles were not significantly attracted to any tested odour, and many PT were damaged by wild boars (Sus scrofa). Flying males were the most frequent adults observed during the season. The use of a net is necessary to capture the stag beetles, in order to evaluate the population parameters and to assess the local status of threat for the species. Capture data revealed that body size (i.e. body weight and elytron length) influences the survival probability of stag beetles, showing a lower survival probability for larger males. Felt-tip pen marking on the ventral sclerites of head and pronotum is a reliable and long lasting method for marking beetles, as proved by the use of an independent marking procedure with a small drill. Assessing the presence and threat status of L. cervus across Europe is urgently needed, and with no efficient odour-based strategy available, collection of adult beetles, dead or alive, by VES is the most reliable way to monitor this emblematic species.

A review of Turkish saproxylic beetles from the European Red List

SummaryThe conservation of beetles that depend on dying or dead wood (i.e. saproxylic), has received a great deal of attention in many parts of the world in recent years. Human activities such as urbanization and logging, and their results, e.g. global warming, destroy natural ecosystems and threaten unusual species such as Lucanus cervus (L. 1758), Rosalia alpina (L. 1758), Limoniscus violaceus (Müller 1821) and Osmoderma eremita (Scopoli 1763). Attempts have been made to conserve the habitats upon which these species depend. Although represented by a large number of species, saproxylic beetles in Turkey have not received much attention. Although some Turkish studies have acknowledged their value, comprehensive investigations of these species are very limited. The aim of this study is to make a list, from the literature, of the species that are endangered in Europe and found in Turkey, to highlight the importance of these species. The research includes 151 saproxylic beetle species belonging to the families Bostrichidae, Cerambycidae, Elateridae, Eucnemidae, Scarabaeidae, Euchiridae, Lucanidae and Mycetophagidae. The list of Turkish saproxylic beetles was prepared using the European Red List of Saproxylic Beetles. Information is provided about the IUCN Red List category in Europe, the locations of the species in Turkey, and their global geographic range. We gathered all data about these species from the international literature. Furthermore, we also include in the list certain species whose locations are not specified, but which inhabit Turkey. We obtained their records from some catalogs in Turkey. In addition to the list, we prepared three distribution maps for Turkey. The maps show distribution in Turkey of some species in the Endangered, Vulnerable and Near Threatened categories in the European Red List. It is expected that this study will lead to comprehensive studies on saproxylic beetles from Turkey.

Testing the performance of a fragment of the COI gene to identify western Palaearctic stag beetle species(Coleoptera, Lucanidae).

The taxonomy of stag beetles (Coleoptera: Lucanidae) remains challenging, mainly due to the sexual dimorphism and the strong allometry in males. Such conjecture confounds taxonomic based conservation efforts that are urgently needed due to numerous threats to stag beetle biodiversity. Molecular tools could help solve the problem of identification of the different recognized taxa in the “Lucanus cervus complex” and in some related Palaearctic species. We investigated the potential use of a 670 bp region at the 3’ end of the mitochondrial cytochrome c oxidase subunit I gene (COI) for barcoding purposes (different from the standard COI barcoding region). Well resolved species and subspecies were L. tetraodon, L. cervusakbesianus, L. c. laticornis, as well as the two eastern Asian outgroup taxa L. formosanus and L. hermani. Conversely, certain taxa could not be distinguished from each other based on K2P-distances and tree topologies: L. c. fabiani / L. (P.) barbarossa, L. c. judaicus / an unknown Lucanus species, L. c. cervus / L. c. turcicus / L. c. pentaphyllus / L. (P.) macrophyllus / L. ibericus. The relative roles of phenotypic plasticity, recurrent hybridisation and incomplete lineage sorting underlying taxonomic and phylogenetic discordances are discussed.

Romanian Species of Lucanids (Coleoptera: Scarabaeoidea: Lucanidae) in the Collections of “Grigore Antipa” National Museum of Natural History

Abstract The seven species of stag beetles of the Romanian fauna are present in the coleopteran collection of the Museum: Aesalus scarabaeoides scarabaeoides (Panzer), Ceruchus chrysomelinus (Hochenwarth), Sinodendron cylindricum (Linnaeus), Lucanus cervus cervus (Linnaeus), Platycerus caraboides caraboides (Linnaeus), Platycerus caprea (De Geer) and Dorcus parallelipipedus (Linnaeus). Information on the collecting data and distribution maps are given for each species. We present the male and female habitus for the two species of Platycerus.

New Data on the Knowledge of Beetle Fauna (Insecta: Coleoptera) in the “Bârnova-Repedea Forest” Site of Community Importance (Rosci 01235, Iaşi, Romania

Abstract 103 coleopteran species, belonging to 11 families were found during our faunal sampling in 2012 in the Bârnova-Repedea Forest site. Out of them Carabus variolosus Fabricius, Lucanus cervus (Linnaeus), Cerambyx cerdo Linnaeus, Morimus funereus Mulsant and Rosalia alpina (Linnaeus) are species of community interest, included in the Annex II of the Habitat Directive. Carpelimus gusarovi Gildenkov and Stenus doderoi Bondroit were collected by the authors, for the first time in Romania. Carabus excellens (Fabricius), a rare species, was rediscovered in this site, and specific faunistic data on the species Colon (Myloechus) dentipes (C. R. Sahlberg) are provided for the first time.

Indirect closing of elytra by the prothorax in beetles (Coleoptera): general observations and exceptions

Voluntary movements of the prothorax and the elytra in tethered flying beetles and manually induced movements of these parts in fresh dead beetles were recorded in 30 species representing 14 families. Participation of prothoracic elevation in the closing of the elytra was demonstrated in three ways. (i) The elevation was always simultaneous with elytral closing, in contrast to depression and elytral opening; a rare exception occurred in Lucanus cervus, whose elytra sometimes started to close before the cessation of wing strokes and the elevation of the prothorax. (ii) The manipulated elevation always induced closing of the spread elytra; the mechanical interaction between the hind edge of the pronotum and the roots of the elytra is a universal mechanism of closing the elytra in beetles. (iii) The prevention of pronoto-elytral contact in live beetles by the excision of the hind edge of the pronotum in front of the root prevented elytral closing after normal flight. Exceptions to this rule included some beetles that were able to close their elytra after such an excision: tiger beetles and diving beetles (seldomly) and rose chafers (always). This ability in Adephaga may be explained by attachments of the muscle actuating the 4th axillary plate, which differ from the attachments in Polyphaga. Cetoniinae open their elytra only by a small amount. It is proposed that their small direct adductors in combination with the elasticity of the sclerites are enough to achieve elytral closing without additional help from the prothorax.

Seasonal constraints on the mandible allometry of Lucanus cervus (Coleoptera: Lucanidae)

In insects, allometries of exaggerated traits such as horns or mandibles are often considered species specific and constant during a season. However, given that constraints imposed by the advancing season affect the developmental processes of organisms, these allometries may not be fixed, and the switch point between morphs may vary between populations and within populations during a season. The hypothesis of such a seasonal variation in exaggerated traits was tested using the dimorphic males of the beetle Lucanus cervus. The remains of specimens killed by predators were collected along forest tracks from mid May to late August 2008 in a protected lowland forest in northern Italy. The largest beetles were collected in mid May and average size thereafter decreased. Males collected early in the season mostly had large mandibles (i.e. they belonged to the major morph). In contrast, late in the season the probability of finding males with large mandibles was very low. The threshold body size determining morph expression also shifted during the season. Early in the season, the threshold pronotum width for a 50% chance of developing into the major morph was 1.74 cm, whereas later in the season it was 1.90 cm. This shift in the threshold body size was interpreted as the effect of phenotypic plasticity in a population exposed to constraints imposed by the advancing season.