Beetle Species Research Articles

Antennal chemoreceptors in the European ectoparasitoid Sclerodermus cereicollis (Hymenoptera: Bethylidae).

Sclerodermus cereicollis is a European flat wasp ectoparasitoid of some longhorn beetle species. This species is important as a suitable biological control agent against xylophagous pests. To better understand its chemical ecology, the ultrastructure of the antennal sensilla of the adult was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensilla are located mainly in the ventro-medial side of the antennae. We report a clearly sexual dimorphism with respect to antennae length, and to types, number, and distribution of chemosensilla. The antennae in males are significantly longer than those of females. We describe in detail the external and internal structure of different chemoreceptors represented by sensilla placodea, long sensilla basiconica, multiporous sensilla chaetica, grooved sensilla ampullacea, uniporous grooved sensilla chaetica. The potential involvement of the different kinds of chemoreceptors in inter- (mainly sexual recognition and social behavior-kin recognition) or intra-specific communication (mainly host selection) is discussed on the basis of behavioral and electrophysiological investigations performed on other parasitoid species belonging to the same family. Other sensilla with morphology that is not consistent with that of chemoreceptors are represented by grooved pegs, coeloconic pegs, trichoid sensilla. Such detailed ultrastructural investigation of the flagellar chemoreceptors of S. cereicollis, clarifying the number of chemosensory neurons innervating the different sensilla, is crucial for further electrophysiological investigations on this important species. RESEARCH HIGHLIGHTS: Evident sexual dimorphism concerning antennae length, type, number, and distribution of chemosensilla. Long sensilla basiconica (LSB) present only in females could play a role in host location and/or maternal care. Multiporous sensilla chaetica (MSC), significantly longer and mostly represented in males, could play a role in the perception of sexual pheromones. Detailed ultrastructural study is crucial for electrophysiological investigations on this important species.

Trait-environment interactions of saproxylic beetles as a guide to biodiversity conservation strategies

Conservation of biodiversity requires in-depth knowledge of trait-environment interactions to understand the influence the environment has on species assemblages. Saproxylic beetles exhibit a wide range of traits and functions in the forest ecosystems. Understanding their responses to surrounding environment thus improves our capacity to identify habitats that should be restored or protected. We investigated potential interactions between ecological traits in saproxylic beetles (feeding guilds and habitat preferences) and environmental variables (deadwood, type and age of surrounding forest). We sampled beetles from 78 plots containing newly created high stumps of Scots pine and Silver birch in boreal forest landscapes in Sweden for three consecutive years. Using a model based approach, our aim was to explore potential interactions between ecological traits and the surrounding environment at close and distant scale (20 m and 500 m radius). We found that broadleaf-preferring beetle species are positively associated with the local broadleaf-originated deadwood and broadleaf-rich forests in the surrounding landscapes. Conifer-preferring species are positively associated with the local amount of coniferous deadwood and young and old forests in the surrounding landscape. Fungivorous and predatory beetles are positively associated with old forests in the surrounding landscapes. Our results indicate that both local amounts of deadwood and types of forests in the landscape are important in shaping saproxylic beetle communities. We particularly highlight the need to increase deadwood amounts of various qualities in the landscape, exempt older forests from production and to increase broadleaf-rich habitats in order to meet different beetle species’ habitat requirements. Trait responses among saproxylic beetles provide insights into the significance of broadleaf forest and dead wood as essential attributes in boreal forest restoration, which helps conservation planning and management in forest landscapes.

Eye development influences horn size but not patterning in horned beetles.

Understanding the origin of novel morphological traits is a long-standing objective in evolutionary developmental biology. We explored the developmental genetic mechanisms that underpin the formation of a textbook example of evolutionary novelties, the cephalic horns of beetles. Previous work has implicated the gene regulatory networks associated with compound eye and ocellar development in horn formation and suggested that horns and compound eyes may influence each other's sizes. Therefore, we investigated the functional significance of genes central to visual system formation in the initiation, patterning, and size determination of head horns across three horned beetle species. We find that while the downregulation of canonical eye patterning genes reliably reduces or eliminates compound eye formation, it does not alter the position or shape of head horns yet does result in an increase in relative horn length. We discuss the implications of our results for our understanding of the genesis of cephalic horns in particular and evolutionary novelties in general.

New masquerade observations of Turkish leaf beetles (Coleoptera: Chrysomelidae)

Thirty-five observations of 25 leaf beetle species and their feeding damage are reported. The beetles belong to 13 genera. Obvious masquerade is found in 29 observations. Nine beetle species in our sample are light in color, but two, being generally light colored, have a wide dark stripe along the elytral suture, so that on the photos (and presumably to visual predators in the field) they appear dark. Feeding damage that these two are surrounded with is also dark. In six observations light colored beetles were making light colored damage. In five examples dark colored beetles were observed among both light and dark colored damage. In remaining observations dark colored beetles were making dark colored damage. Masquerade in Cassidinae and larvae of Alticini and Galerucini is reported here for the first time. In addition, observation of flea beetle interacting with ants on leaf surface and use of feeding holes to move from the upper to the lower leaf surface are reported.

Effects of Eucalyptus wood and leaf litter on saproxylic insects in the southeastern United States

Although Eucalyptus is widely planted outside its native range for timber and pulp production, the effects of these exotic plantations on biodiversity relative to native semi-natural forests or plantations of native tree species remain incompletely understood. Here, we compare the diversity of saproxylic beetles (Coleoptera) and true bugs (Hemiptera) between non-native Eucalyptus benthamii Maiden and Cambage (Camden white gum) and native Pinus taeda L. (loblolly pine) stands on the upper Coastal Plain of South Carolina, U.S.A. We sampled insects emerging from logs of both species placed in both stand types after 1, 2, 6, and 12 months in the field. Beetle and true bug richness and diversity were both significantly lower from eucalypt than from pine wood. Moreover, the two communities were compositionally distinct. Whereas pine supported many species of host-specific phloeoxylophagous beetles, most species collected from eucalypts were mycophagous or predatory taxa capable of utilizing a wide range of hosts. Species richness did not differ between logs placed in eucalypt vs. pine stands but Shannon’s diversity was significantly higher in the eucalypt stands, possibly due to greater sun exposure in the latter. Contrary to a previous study, we found no support for the idea that eucalypt litter reduces the diversity of saproxylic insects. Our findings add to the growing body of evidence that non-native plantations are less favorable to biodiversity than those consisting of native tree species.

Diel activity patterns of a canopy-inhibiting beetle community (Coleoptera) in a Neotropical rainforest

Diel activity is one main feature of animal‘s behavior and is often an intrinsic trait characterizing distinct taxonomic groups. Abiotic conditions such as temperature may influence the diel activity patterns of arthropod communities associated with a particular ecosystem or habitat. Similarly, biotic factors, such as resource availability, affect arthropod activity. In addition, diel activity is thought to be an important factor in niche partitioning of arthropod communities. As part of a larger beetle survey in a lowland tropical rainforest in southern Venezuela, I analyzed the diel activity of an arboreal beetle community collected from 23 canopy-tree species over a cumulative year. Diel activity was observed in 535 beetle species, comprising 5,948 individuals, using a canopy crane installed in the study area. Of the 535 beetle species, 198 (37%) showed diurnal activity, and 281 (52.5%) showed nocturnal activity. In contrast, the proportions of nocturnal (n = 2,024, 34%) and diurnal (n = 1,983, 33.3%) individuals were balanced. Most of the observed beetles occurred only during the activity phase in their host trees. This particularly applies to extrafloral nectary- and flower-visiting beetle species. Flowering trees attracted different proportions of diurnal and nocturnal species according to flowering syndrome, whereas extrafloral nectaries were mainly visited at night. Thus, the beetle communities associated with single tree species showed distinct compositions of nocturnal and diurnal species.

Comparing the efficacy and cost-effectiveness of two sampling methods for monitoring carabid beetle diversity, species assemblages and conservation status in an alpine grassland

Comparing the efficacy and cost-effectiveness of two sampling methods for monitoring carabid beetle diversity, species assemblages and conservation status in an alpine grassland

Gregarines impact consumption and development but not glucosinolate metabolism in the mustard leaf beetle

Gregarines are usually classified as parasites, but recent studies suggest that they should be viewed on a parasitism-mutualism spectrum and may even be seen as part of the gut microbiota of host insects. As such, they may also impact the consumption of their hosts and/or be involved in the digestion or detoxification of the host’s diet. To study such effects of a gregarine species on those traits in its host, the mustard leaf beetle (Phaedon cochleariae) was used. This beetle species feeds on Brassicaceae plants that contain glucosinolates, which form toxic compounds when hydrolyzed by myrosinases. We cleaned host eggs from gametocysts and spores and reinfected half of the larvae with gregarines, to obtain gregarine-free (G-) and gregarine-infected (G+) larvae. Growth and food consumption parameters of these larvae were assessed by rearing individuals on watercress (Nasturtium officinale, Brassicaceae). A potential involvement of gregarines in the glucosinolate metabolism of P. cochleariae larvae was investigated by offering G- and G+ larvae leaf discs of watercress (containing mainly the benzenic 2-phenylethyl glucosinolate and myrosinases) or pea (Pisum sativum, Fabaceae, lacking glucosinolates and myrosinases) treated with the aliphatic 4-pentenyl glucosinolate or the indole 1-methoxy-3-indolylmethyl glucosinolate. Larval and fecal samples were analyzed via UHPLC-QTOF-MS/MS to search for breakdown metabolites. Larval development, body mass, growth rate and efficiency to convert food into body mass were negatively affected by gregarine infection while the pupal mass remained unaffected. The breakdown metabolites of benzenic and aliphatic glucosinolates were conjugated with aspartic acid, while those of the indole glucosinolate were conjugated with glutamic acid. Gregarine infection did not alter the larvae’s ability to metabolize glucosinolates and was independent of plant myrosinases. In summary, some negative effects of gregarines on host performance could be shown, indicating parasitism. Future studies may further disentangle this gregarine-host relationship and investigate the microbiome potentially involved in the glucosinolate metabolism.

The Potential of Artificial Snags to Promote Endangered Saproxylic Beetle Species in Bavarian Forests

The creation of artificial snags, so-called high stumps, within forest management operations is a recently established tool to enrich standing deadwood as a habitat for saproxylic species. In this study, we analysed the impact of active high stump management on saproxylic beetle species. We selected 63 high stumps in six Bavarian forest districts (Germany), which were felled and subjected to close examination, focusing on beetle (Coleoptera) colonization. We identified 63 emerged coleopteran species belonging to 29 families; a further 10 taxa were identified only at the genus or family level, respectively. Moreover, 17% of the obtained taxa are listed in the German Red List of Coleoptera. Furthermore, 32% of the examined high stump trunks, predominantly broad-leaved tree species, harboured Red List beetle taxa. In particular, trembling aspen (Populus tremula) showed a disproportionately high number of Red List beetle species. The total species richness of beetles was independent of the height, diameter and decay stage of the snags. High stumps (snags) containing Red List beetle species tended to have higher amounts of deadwood in their surroundings, but the difference was not significant. According to the results of our study, actively creating high stumps proved to be a suitable method for creating habitats and serve as stepping-stones for endangered saproxylic species. Proactive high stump management during harvest can be a valuable component of deadwood management and biodiversity protection in forests.

Residual Efficacy of Two Diatomaceous Earths from Greece for the Control of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) on Wheat and Maize

We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The formulations were applied as powders in soft wheat and maize in two doses of 500 and 1000 mg kg−1 (ppm). Samples of the treated grains were taken on the day of application and every 30 days until completion of the six-month period of storage. Adults of S. oryzae and R. dominica were exposed to the treated grains at 25 °C and 55% relative humidity, and the mortality was measured after 7, 14, and 21 days of exposure. Rhyzopertha dominica survival was not affected by any combination of DE formulation, dose, and commodity. Contrariwise, the DEs caused significant adult mortality of S. oryzae, in most of the cases tested. We observed that DE6 was equally effective in both wheat and maize, and no considerable variations were observed in S. oryzae mortality during the 6-month experimental period. Furthermore, DE6 was more effective against S. oryzae than DE5, a difference that could have potentially contributed to the variations in the diatom granulometry between these two DEs. Thus, a DE treatment of 1000 ppm was shown to provide long-term protection of wheat and maize against S. oryzae, but this is strongly dependent on the DE formulation, commodity, and insect species. Overall, such natural resource-based inert silicaceous deposits could be used with success in stored-product protection with only some minor modifications, such as sieving and drying of the raw deposit.

Expanded Geographical Distribution of Coleomegilla maculata lengi (Coleoptera: Coccinellidae) in North America

Several species of lady beetle native to North America have declined in abundance in the last few decades, often accompanied by contractions in their geographic ranges. Coleomegilla maculata lengi is a lady beetle native to North America that is an important predator of pests in various agroecosystems. Its reported range spans the eastern half of the USA, with no sustained decline in abundance or contraction of its range reported. Indeed, we recently collected several individuals of this lady beetle in central USA roughly 500 km beyond the western edge of its reputed range. We hypothesized that new records could indicate either that previous range characterization failed to include pre-existing collection records further west or that C. maculata lengi has recently expanded its geographic range. To test these hypotheses, we searched several institutional insect collections and digital databases for records and found many earlier records of C. maculata lengi beyond its reputed geographic range, clearly showing that the previous characterization of its geographic distribution in North America was substantially underestimated. In addition, we report a new state record of C. maculata lengi from Wyoming, USA, that further indicates its geographic range expansion in North America. We discuss new records of C. maculata lengi in light of declines in native coccinelline lady beetle species in North America.

Mammal species biodiversity in a Costa Rican protected tropical rainforest environment

Tropical rainforest deforestation has led to old-growth forest loss and declines in species diversity worldwide. In the 1980’s, Costa Rica began innovative reforestation efforts and currently 52% of Costa Rica is a tropical forest environment. However, the impact of Costa Rica’s reforestation efforts on regaining species biodiversity is less known. The aim of this study was to consider longitudinal changes in mammal biodiversity at La Selva Biological Station (LSBS) following reforestation. Mammal species census data were collected between 1994 and 2017 by 30-60 trained and experienced Citizen Scientists. We calculated the total number of different species sighted per year, their relative abundance, and the Shannon Index to estimate biodiversity. Linear regression was used to consider change over time and ANOVA was used to consider differences in land and water use by mammal species (p<0.05). Results suggest the total number of different species observed declined, their relative abundance declined, and the Shannon index of biodiversity declined (p<0.05). This decline is similar to that reported for avian fauna, terrestrial amphibian, and dung beetle species reported at LSBS. Our study highlights the concern that past deforestation continues to lead to species decline and the ongoing need for tropical forest stewardship.

Evidence for 3-hydroxyhexan-2-one as a shared pheromone component for 12 South American species of cerambycid beetles.

3-Hydroxyhexan-2-one (3-C6-ketol) has emerged as the most conserved pheromone structure within the beetle family Cerambycidae. In this study, we report the sex-specific production of this compound by males of 12 species of South American cerambycid beetles. Males of Chrysoprasis chalybea Redtenbacher and Mallosoma zonatum (Sahlberg) (Tribe Dichophyiini), and Ambonus lippus (Germar), Eurysthea hirta (Kirby), Pantonyssus nigriceps Bates, Stizocera plicicollis (Germar), and Stizocera tristis (Guérin-Méneville) (Elaphidiini) produced 3R-C6-ketol as a single component, whereas males of Neoclytus pusillus (Laporte & Gory) (Clytini), Aglaoschema concolor (Gounelle), Orthostoma abdominale (Gyllenhal) (Compsocerini), Dorcacerus barbatus (Olivier), and Retrachydes thoracicusthoracicus (Olivier) (Trachyderini) produced 3R-C6-ketol, along with lesser amounts of other compounds. In field trials testing 8 known cerambycid pheromone compounds, C. chalybea, E. hirta, and R. t. thoracicus were attracted in significant numbers to traps baited with 3-C6-ketol. A second field experiment provided support for the strategy of using the attraction of cerambycid species to test lures as a method of providing leads to their likely pheromone components. Because both sexes are attracted to these aggregation-sex pheromones, live beetles can be obtained from baited traps to verify they produce the compound(s) to which they were attracted, that is, that the compounds are indeed pheromone components.

Additions to the taxonomy of the genus Ophionea Klug, 1821 (Coleoptera: Carabidae: Lebiinae) and a new species from India

A new ground beetle species Ophionea vvrei sp. nov. is described from South India, with revised key to the species of the genus Ophionea, revised descriptions of O. bhamoensis bhamoensis (Bates, 1892) and O. interstitialis Schmidt-Göbel, 1846, first report of Ophionea ceylonica (Baehr, 1996) from Indian mainland and designation of the lectotype of O. indica (Thunberg, 1784).

Edge history modulates the depth of edge influence: Evidence from ground beetles with different feeding traits

Anthropogenic habitat loss and fragmentation are major concerns to conservationists, since these processes lead to species decline and extinction. Edge effect is one of the most important causes of biodiversity losses in fragmented habitats. The depth of edge influence, the distance over which the edge effect penetrates into the adjacent habitat is a central issue, as it fundamentally determines whether the habitat fragment has any remaining core habitat, which is essential for the survival of habitat specialist species. We reviewed 204 edge studies on ground beetles (Coleoptera: Carabidae) of different feeding habits, in forests, one of the habitats most impacted by humans. Meta-analysing 1814 abundance data of 351 ground beetle species from forest edges and their adjoining interiors, we showed that forest edges had significantly higher abundance of herbivorous, omnivorous, and predatory ground beetles than their interiors. Edge history considerably affected the depth of edge influence which on all trophic groups was similar in natural edges and those maintained by agriculture (≤ 10–20 m), while it was wider (> 300 m) when created by forestry or other anthropogenic activities. Consequently, the minimum area of a forest fragment should be ∼ 330 ha in order to keep half of it as core habitat to preserve forest-interior species.

Why are there so many beetle species?

Why are there so many beetle species?

Unexpected Formation of 11(9→7)-abeo-Steroid Skeleton in Synthetic Studies toward Batrachotoxin.

Batrachotoxin (1) is a potent cardio- and neurotoxic steroid isolated from certain species of frogs, birds, and beetles. We previously disclosed two synthetic routes to 1. During our synthetic studies toward 1, we explored an alternative strategy for efficiently assembling its 6/6/6/5-membered steroidal skeleton (ABCD-ring). Here we report the application of intermolecular Weix and intramolecular pinacol coupling reactions. While Pd/Ni-promoted Weix coupling linked the AB-ring and D-ring fragments, SmI2-mediated pinacol coupling did not cyclize the C-ring. Instead, we discovered that SmI2 promoted a 1,4-addition of the α-alkoxy radical intermediate to produce the unusual 11(9→7)-abeo-steroid skeleton. Thus, this study demonstrates the convergent assembly of the skeleton of the natural product matsutakone in 11 steps from 2-allyl-3-hydroxycyclopent-2-en-1-one.

First Description of the Immature Stages of Philonthus spinipes Sharp, 1874 (Coleoptera: Staphylinidae: Staphylininae) – An Adventive Rove Beetle Species in Europe, with Notes on Its Biology, Ecology and Zoogeography

First Description of the Immature Stages of Philonthus spinipes Sharp, 1874 (Coleoptera: Staphylinidae: Staphylininae) – An Adventive Rove Beetle Species in Europe, with Notes on Its Biology, Ecology and Zoogeography

Cretafrica orapensis: a new genus and species of Mycetoporinae (Coleoptera: Staphylinidae) from lacustrine deposits at Orapa Diamond Mine, Botswana

Abstract A new genus and species of staphylinid beetle, Cretafrica orapensis gen. nov. et sp. nov. is described using a single well-preserved impression fossil from an Upper Cretaceous fossil insect deposit, the Orapa Diamond Mine in Botswana. Cretafrica is placed in the extant subfamily Mycetoporinae based on its general habitus, typical sublimuloid medium-to-large body form, elongated head, visible ridge on ventral side of head under eyes, antennomeres increasing in length and width apically, scutellum with basal carina that is distinctly divided medially, elevated area along suture of the elytra, and presumably large metacoxae, and tapering abdomen. It differs from other Mycetoporinae by its triangular head and elytra with broadly rounded apico-lateral margins. A possible preservation distortion illustrates brush-like or fork-like mouthparts. The fossil insect may have been found in forest litter or fresh and rotting mushrooms at Orapa. It confirms the widespread distribution of mycetoporines with phytophagous or mycophagous lifestyles during the mid-Cretaceous. Moreover, like other described fossil staphylinids, the fossil portrays morphological stasis dating back to the Cretaceous. It further confirms the proposed punctuated equilibrium pattern of evolution.

Материалы к фауне стафилинид (Coleoptera: Staphylinidae) севера Корякии (Камчатский край)

Fifty species of rove beetles from twenty-six genera, belonging to the nine subfamilies (without subfamily Aleocharinae) are recorded for the fauna of the northern part of Koryakia (Kamchatskiy Kray). A table of list of species is presented. Collecting localities are mapped.