Chromosomal mapping of repetitive DNAs in the beetle Dichotomius geminatus provides the first evidence for an association of 5S rRNA and histone H3 genes in insects, and repetitive DNA similarity between the B chromosome and A complement

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seasonal and spatial species richness variation of dung beetle (Coleoptera, Scarabaeidae s. str.) in the Atlantic Forest of southeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identification of sulcatol, a potential pheromone of the ambrosia beetle Gnathotrichus materiarius (Col., Scolytidae)

We report the identification of a potential pheromone for Gnathotrichus materiarius (Fitch) (Col., Scolytidae). The population sex ratio is close to 1:1, and males initiate attacks on host trees. Headspace and hindgut samples from single males showed the presence of the putative pheromone 6-methyl-5-hepten-2-ol, sulcatol. Unmated males released sulcatol for at least 12 days, and ceased producing the pheromone after 20 days. The peak sulcatol release occurred after 2 days. Males cease production of sulcatol 24 h after being paired with females. Single females were unable to initiate galleries, and no sulcatol was detected from their headspace and hindgut samples. The chiral ratio of the pheromone, observed from headspace samples, was 31% (S)-(+)- and 69% (R)-(-)-sulcatol.

Mitochondrial genome sequence of the Brazilian luminescent click beetle Pyrophorus divergens (Coleoptera: Elateridae): Mitochondrial genes utility to investigate the evolutionary history of Coleoptera and its bioluminescence

The Coleoptera order is the richest group among Metazoa, but its phylogenetics remains incompletely understood. Among Coleoptera, bioluminescence is found within the Elateroidea, but the evolution of this character remains a mystery. Mitochondrial DNA has been used extensively to reconstruct phylogenetic relationships, however, the evolution of a single gene does not always correspond to the species evolutionary history and the molecular marker choice is a key step in this type of analysis. To create a solid basis to better understand the evolutionary history of Coleoptera and its bioluminescence, we sequenced and comparatively analyzed the mitochondrial genome of the Brazilian luminescent click beetle Pyrophorus divergens (Coleoptera: Elateridae). © 2007 Elsevier B.V. All rights reserved.

The influence of the loop between residues 223-235 in beetle luciferase bioluminescence spectra: A solvent gate for the active site of pH-sensitive luciferases

Beetle luciferases emit a wide range of bioluminescence colors, ranging from green to red. Firefly luciferases can shift the spectrum to red in response to pH and temperature changes, whereas click beetle and railroadworm luciferases do not. Despite many studies on firefly luciferases, the origin of pH-sensitivity is far from being understood. Through comparative site-directed mutagenesis and modeling studies, using the pH-sensitive luciferases (Macrolampis and Cratomorphus distinctus fireflies) and the pH-insensitive luciferases (Pyrearinus termitilluminans, Phrixotrix viviani and Phrixotrix hirtus) cloned by our group, here we show that substitutions dramatically affecting bioluminescence colors in both groups of luciferases are clustered in the loop between residues 223-235 (Photinus pyralis sequence). The substitutions at positions 227, 228 and 229 (P. pyralis sequence) cause dramatic redshift and temporal shift in both groups of luciferases, indicating their involvement in labile interactions. Modeling studies showed that the residues Y227 and N229 are buried in the protein core, fixing the loop to other structural elements participating at the bottom of the luciferin binding site. Changes in pH and temperature (in firefly luciferases), as well as point mutations in this loop, may disrupt the interactions of these structural elements exposing the active site and modulating bioluminescence colors. © 2007 The Authors.

Pyrearinus termitilluminans larval click beetle luciferase: Active site properties, structure and function relationships and comparison with other beetle luciferases

Several beetle luciferases have been cloned and sequenced. However, most studies on structure and function relationships and bioanalytical applications were done with firefly luciferases, which are pH sensitive. Several years ago we cloned Pyrearinus termitilluminans larval click beetle luciferase, which displays the most blue-shifted bioluminescence among beetle luciferases and is pH insensitive. This enzyme was expressed in E. coli, purified, and its properties investigated. This luciferase shows slower luminescence kinetics, KM values comparable to other beetle luciferases and high catalytic constant. Fluorescence studies with 8-anilino-1-naphtalene-sulfonic acid (1,8-ANS) and modeling studies suggest that the luciferin binding site of this luciferase is very hydrophobic, supporting the solvent and orientation polarizability effects as determining mechanisms for bioluminescence colors. Although pH insensitive in the range between pH 6-8, at pH 10 this luciferase displays a remarkable red-shift and broadening of the bioluminescence spectrum. Modeling studies suggest that the residue C312 may play an important role in bioluminescence color modulation. Compared to other beetle luciferases, Pyrearinus termitilluminans luciferase also displays higher thermostability and sustained luminescence in a bacterial cell environment, which makes this luciferase particularly suitable for in vivo cell analysis and bioimaging. © The Royal Society of Chemistry and Owner Societies 2009.

Selective defaunation affects dung beetle communities in continuous Atlantic rainforest

Overhunting has caused severe decline or local extinction in many large-bodied mammals with direct consequences on plant regeneration, yet little is known about indirect impacts of selective defaunation on commensal species. Cascading effects of species extinction across dependent species groups are likely to occur in coprophagous beetles, because these invertebrates rely on mammal dung for food and nesting material. Both mammals and dung beetles provide important ecosystem services and cascading effects are likely to lead to rapid functional losses. In this study, we described changes in dung beetle communities across a gradient of selective defaunation in continuous Brazilian Atlantic rain forest. We compared the dung beetle assemblages in seven sites with different mammalian biomass and composition. The reduction in the mammalian biomass had a major effect on dung beetle communities by (1) increasing dung beetle abundance with decreasing overall mammal, primate and large mammal biomasses, (2) decreasing dung beetle species richness with decreasing overall mammal biomass and (3) decreasing dung beetle size with decreasing large mammal biomass. Moreover, our study demonstrated the importance of the composition of mammal communities in structuring dung beetle communities. This study documented how selective changes in mammalian biomass and composition affect dung beetle species communities, which in turn may have cascading consequences for the ecosystem. Since most of tropical ecosystems are facing dramatic changes in mammalian composition, it is urgent to evaluate the functional losses associated with such co-extinctions. © 2013 Elsevier Ltd.

Heterochromatin and molecular characterization of DsmarMITE transposable element in the beetle Dichotomius schiffleri (Coleoptera: Scarabaeidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Protocylindrocorpus brasiliensis n. sp. (Diplogastroidea: Cylindrocorporidae) associated with the ambrosia beetle, Euplatypus parallelus (f.) (Curculionidae: Platypodinae) in para rubber trees (Hevea brasiliensis)

Protocylindrocorpus brasiliensis n. sp. (Diplogastroidea: Cylindrocorporidae) is described from reproductive stages removed from galleries of the ambrosia beetle, Euplatypus parallelus (F.) (Curculionidae: Platypodinae) in Para rubber trees (Hevea brasiliensis) in Brazil. This is the first record of the genus Protocylindrocorpus from the Neotropics. Males of P. brasiliensis are quite striking because their long spicules extend up to 72% of their total body length. The adults exhibit conspecific agglutination where they congregate in a slimy substance that serves to maintain them in a coherent group for mating. Some of the adults were infected by fungal and protozoan pathogens, implying that disease plays a role in regulating natural populations. The discovery of P. brasiliensis provides new information on nematode structure, behavior, and ecology.

Western Balsam Bark Beetle, Dryocoetes confusus Swaine, Flight Periodicity in Northern Utah

The flight periodicity of western balsam bark beetle (Dryocoetes confusus Swaine) in Big Cottonwood Canyon, Utah, was studied during the summer months of 1992, 1993, and 1994. Contents of baited funnel traps were tallied by species up to 3 times weekly. Two main periods of flight activity were observed each year. The first and, generally, largest occurred in early summer soon after flight was initiated for the season. A 2nd period was observed in late summer, generally August. Timing of the 2 periods was influenced by unusually warm or cool weather in each study year. The 1st period had more males than females while the 2nd period had a majority of females. Except during periods of cool or wet weather, western balsam bark beetles were found to be active at least at minimal levels from June through September.

Electrophysiological Responses of the Naupactus bipes Beetle to Essential Oils from Piperaceae Species

Electrophysiological responses based on electroantennographic detection (GC-EAD) and electroantennography (EAG) analysis of Naupactus bipes beetles (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) were used to test volatile oils of Piper gaudichaudianum, P. regnellii and P. hispidum. In the EAG experiments, female and male beetles showed significant EAG response to the three volatile oils of Piper species, with the females' responses slightly higher than the males'. The experiments with GC-EAD revealed that some terpenoids (namely, alpha-pinene, beta-pinene, myrcene, alpha-copaene and germacrene) present in the leaf essential oils of the Piper species are perceptible to female and male beetles.

The alternative Pharaoh approach: stingless bees mummify beetle parasites alive

Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and their parasites.