Seasonality and bait type driving the diversity of dung beetle (Scarabaeidae: Scarabaeinae) communities in urban remnants of the Atlantic Forest

ABSTRACT Describing dung beetle communities in tropical forest remnants located in disturbed/urbanized and conserved areas can provide information about the functioning of these ecosystems and support conservation plans. This study aimed to verify the effect of seasons and bait type on dung beetle communities in remnants of the Atlantic Forest in order to describe their composition and diversity parameters. The study was carried out during both the rainy and dry seasons in periurban and urban remnants. Eighteen pitfall traps baited with feces, carrion, and injured millipedes were established in each site. A total of 3501 individuals and 23 species were recorded. Urban remnant presented higher abundance of individuals in the dry season. On the other hand, in periurban remnant the higher abundance was verified in the rainy season. The diversity was higher in the rainy season in both sites. In urban remnant, Coprophanaeus ensifer was found to be generalist regarding its choice of bait (feces and carrion). The use of injured millipedes as bait allowed the record of the predatory species Deltochilum alpercata. Among the types of bait used, the injured millipedes proved to be very effective, capturing a greater diversity of dung beetles during the rainy season in both remnants, and allowed the collection of specialized, necrophages, and generalists species. Therefore, we propose the use of mixed-bait sampling designs in inventories and surveys to increase the chances of sampling species with different traits or dietary preferences, which are often rare in collections.

Comparative cytogenetics of three species of Dichotomius (Coleoptera, Scarabaeidae)

Meiotic and mitotic chromosomes of Dichotomius nisus, D. semisquamosus and D. sericeus were analyzed after conventional staining, C-banding and silver nitrate staining. In addition, Dichotomius nisus and D. semisquamosus chromosomes were also analyzed after fluorescent in situ hybridization (FISH) with an rDNA probe. The species analyzed had an asymmetrical karyotype with 2n = 18 and meta-submetacentric chromosomes. The sex determination mechanism was of the Xy p type in D. nisus and D. semisquamosus and of the Xyr type in D. sericeus. C-banding revealed the presence of pericentromeric blocks of constitutive heterochromatin (CH) in all the chromosomes of the three species. After silver staining, the nucleolar organizer regions (NORs) were located in autosomes of D. semisquamosus and D. sericeus and in the sexual bivalent of D. nisus. FISH with an rDNA probe confirmed NORs location in D. semisquamosus and in D. nisus. Our results suggest that chromosome inversions and fusions occurred during the evolution of the group.

Diversidade de Scarabaeinae (Coleoptera, Scarabaeidae) coletados com armadilha de interceptação de vôo no Refúgio Ecológico Charles Darwin, Igarassu-PE, Brasil / Diversity of Scarabaeinae (Coleoptera, Scarabaeidae) collected with flight intercept trap in the Charles Darwin Ecologic Refuge, Igarassu-PE, Brazil

O objetivo deste trabalho foi estudar riqueza, abundância, diversidade e equitabilidade das espécies de Scarabaeinae em dois ambientes no Refúgio Ecológico Charles Darwin (RECD), Pernambuco. As coletas foram realizadas com armadilha de interceptação de vôo entre os meses de Abril e Junho de 2007, totalizando seis coletas. Foram capturados 4576 escarabeíneos, pertencentes a 35 espécies, 15 gêneros e seis tribos. Sete novos registros de espécies foram feitos para Pernambuco, passando de 26 para 33 espécies. As tribos registradas foram Canthonini, Ateuchini, Coprini, Phanaeini, Eurystenini e Onthophagini. Os gêneros melhor representados foram: Dichotomius com 84,6 por cento dos besouros coletados, seguido por Canthidium com 7,62 por cento e Canthon com 2,48 por cento. A espécie Dichotomius aff.sericeus foi a mais abundante com 3889 indivíduos. Em todo o estudo foram verificadas 17 espécies para a área aberta, sendo 11 restritas a esse ambiente, enquanto para mata foram registradas 24, sendo 18 espécies restritas. Grande parte dos indivíduos capturados na mata foi da espécie D. aff.sericeus, enquanto no ambiente aberto nenhum indivíduo desta espécie foi coletado. Os estimadores indicaram uma estimativa máxima de riqueza de 21 espécies para o ambiente aberto e 32 espécies para o ambiente de mata. A curva de acumulação de espécies baseada em valores de riqueza observada média para os dois ambientes do RECD, não apresentou tendência a assíntota.

The objective of this work was to study richness, abundance, diversity and equitability of the species of Scarabaeinae, in two environments in the Charles Darwin Ecology Refuge (CDER), Pernambuco. Sampling was carried with flight intercept trap from April through June 2007, totaling six samples. 4576 scarabaeinaes, belonging to 35 species, 15 genera and six tribes were captured. Seven new species records were found for Pernambuco, whose known fauna increased from 26 to 33 species. The tribes recorded were Canthonini, Ateuchini, Coprini, Phanaeinae, Eurystenini and Onthophagini. The better represented genera were: Dichotomius with 84,6 percent of the beetles collected, followed by Canthidium with 7,62 percent and Canthon with 2,48 percent. Dichotomius aff.sericeus was the most abundant species with 3889 individuals. 17 species were sampled in open areas, with 11 of them restricted to this habitat, while 24 were recorded within the forest, 18 of them found only in this habitat. Most individuals captured in the forest belong to D. aff.sericeus, while in open areas no specimen of this species was collected. The estimators indicate a maximum richness of 21 species for the open environment and 32 species for the forest. The species accumulation curve, based on average richness values for the two environments at CDER, did not show tendency to assintote.

High levels of chromosomal differentiation in Euchroma gigantea L. 1735 (Coleoptera, Buprestidae)

Euchroma gigantea was karyotypically studied using conventional staining, C-banding, silver nitrate staining and ribosomal fluorescent in situ hybridization (rDNA FISH). Broad wide autosomal polymorphism and a complex sex determination system were found in this beetle. Karyotype complements ranging from 2n = 32, X1X2X3Y1Y2Y3 to 2n = 36,X1X2X3Y1Y2Y3 were detected in the sample analyzed. Punctiform supernumerary chromosomes were present in the different karyotypes. The karyotypic evolution of Brazilian E. gigantea may have taken two directions, reduction in the diploid number of 2n = 36 to 24 through centric fusions or 2n = 24 to 36 due to chromosomal fissions. In addition, pericentric inversions were also involved. The complex multiple sex mechanism of this species seems to be old and well established since it is found in specimens from different populations. Small pericentromeric blocks of constitutive heterochromatin were located on the autosomes and terminal blocks were also found on some small pairs. The sex chromosomes showed larger constitutive heterochromatin blocks. Silver nitrate staining during prophase I of meiosis showed labeling of the sex chromosome chain. However, the rDNA sites could only be precisely determined by FISH, which permitted the identification of these ribosomal sites on chromosomes X1 and X2 of this species.

Comunidade de escarabeíneos (Coleoptera, Scarabaeidae) copro-necrófagos da região de Brejo Novo, Caruaru, Pernambuco, Brasil / Copro-necrophagous scarab community (Coleoptera, Scarabaeidae) of the Brejo Novo region, Caruaru, Pernambuco, Brazil

Este estudo objetivou levantar preliminarmente os escarabeíneos copro-necrófagos da região de Brejo Novo, Caruaru, Pernambuco, e verificar aspectos da estrutura da comunidade como sazonalidade, diversidade, equitabilidade, riqueza e abundância das espécies. Foram realizadas 10 coletas, com intervalos de 30 dias e duração de 48 horas, de setembro de 2003 a julho de 2004. Utilizaramse 24 armadilhas de queda, com dois tipos de isca, fezes humanas e carne bovina em estado de putrefação. Foram coletados 1.540 indivíduos pertencentes a seis tribos, 12 gêneros e 28 espécies. As espécies Canthon af. carbonarius, Canthon chalybaeus, Dichotomius nisus, D. semisquamosus, Digitonthophagus gazella e Eurysternus hirtellus aparentemente são as mais adaptadas ao ambiente estudado. Foram coletados 826 indivíduos em armadilhas iscadas com fezes humanas e 714 em carne bovina apodrecida. Ocorreu um número maior de espécies consideradas "raras" (15), sendo três destas "singletons", duas "doubletons" e 10 com abundância entre três e 10 indivíduos, 13 espécies foram consideradas "comuns". Das espécies analisadas, sete apresentaram hábitos alimentares generalistas, quatro são estritamente coprófagas e uma estritamente necrófaga. Foram verificadas correlações positivas entre a precipitação mensal e a abundância e a riqueza de espécies. O levantamento preliminar das espécies de Scarabaeinae da região de Brejo Novo contribuiu para aumentar o número de espécies registradas para o estado de Pernambuco e região Nordeste do Brasil.

This paper reports the results of the preliminary survey of copro-necrophagous dung beetles of Brejo Novo region, Caruaru, Pernambuco, as well as some aspects of the community structure such as seasonality, diversity, equitability, richness and abundance of species. Ten samplings with intervals of 30 days and duration of 48 hours, fortnightly were done between September 2003 to July 2004. Scarab beetles were collected with 24 pitfall traps baited with two types of baits, human excrements and rotting bovine meat. A total of 1,540 individuals belonging to six tribes, 12 genera and 28 species were collected. The species Canthon af. carbonarius, Canthon chalybaeus, Dichotomius nisus, D. semisquamosus, Digitonthophagus gazella and Eurysternus hirtellus are, apparently, adapted to the studied environment. Traps baited with human excrements attracted 826 individuals and those with rotting bovine meat attracted 714 specimens. Large number of species (15) considered "rare" occurred, being three of them "singletons", two "doubletons" and 10 with abundance between three and 10 individuals; 13 species were considered "common". Of the analyzed species, seven present generalist alimentary habits, four are strictly coprophagous and one is strictly necrophagous. Positive correlations were verified between the precipitation and the abundance of the individuals and the species richness. This preliminary survey of the dung beetles of the Brejo Novo region contributed to increase the number of species registered for Pernambuco and northeast region of Brazil.

Karyotype, C-and fluorescence banding pattern, NOR location and FISH study of five Scarabaeidae (Coleoptera) species

Meiotic chromosomes obtained from members of the coleopteran subfamilies Rutelinae and Dynastinae were studied using standard and silver nitrate staining, C-banding, base-specific fluorochromes and fluorescent in situ hybridization (FISH). The study presents detailed karyotipic descripitions of three Rutelinae species (Geniates borelli, Macraspis festiva and Pelidnota pallidipennis), and two Dynastinae species (Lygirus ebenus and Strategus surinamensis hirtus) with special emphasis on the distribution and variability of constitutive heterochromatin and the nucleolar organizer region (NOR). We found that for G. borelli, P. pallidipennis, L. ebenus and S. s hirtus the karyotype was 2n = 20 (9II + Xy p), with G. borelli, P. pallidipennis and L. ebenus showed meta-submetacentric chromosomes which gradually decreased in size. For Macraspis festiva the karyotype was 2n = 18 (8II + Xy p). In L. ebenus we found that the NOR was located on an autosome, but in the other four species it occurred on the sex bivalents. In all five species the constitutive heterochromatin (CH) was predominantly pericentromeric while the X chromosomes were almost completely heterochomatic, although CMA3/DA/DAPI staining showed intra and interspecific variation in the bright fluorescence of the constitutive heterochromatin. The FISH technique showed rDNA sites on the X chromosome of the Rutelinae species.