Daily activity of Dichotomius geminatus (Arrow, 1913) and Deltochilum verruciferum Felsche, 1911 (Coleoptera: Scarabaeinae) facing carrion: from resource perception to feeding

Abstract Dung beetles (Scarabaeinae) interact with resources in different ways and are classified according to resource relocation guilds. Dichotomius geminatus (Coprini) and Deltochilum verruciferum (Canthonini) are two of the most abundant and ecologically important species of the semi-arid region of Brazil, and understanding their behaviour may facilitate the comprehension of strategies associated to competition for resources. The aim of the present study was to investigate the behavioural repertoire of D. geminatus (tunneler) and D. verruciferum (roller), in isolation and controlled setting in the Brazilian semi-arid biome, using carrion as a food resource. Our hypothesis was that, due to the distinct food relocation strategies presented by these species, distinct behaviours would occur involving resource utilization. We also compared the behaviour of the two species and investigated the period of diel activity. Both species were more active during the night, but D. geminatus presented a shorter peak of nocturnal activity when compared to D. verruciferum. Although there was activity during the day, feeding was only observed during the night, for both species. During the periods of inactivity, D. verruciferum commonly went underneath the carrion, remaining still. As the target species of the study are very abundant, the differences in behaviour associated with the distinct relocation guilds may indicate a strategy to avoid direct competition.

Flight patterns and sex ratio of beetles of the subfamily Dynastinae (Coleoptera, Melolonthidae)

ABSTRACT Dynastinae is one of the most representative subfamilies of Melolonthidae (Scarabaeoidea) and has considerable ecological importance due mainly to interactions with plants of the families Araceae and Annonaceae. This relationship has led to the evolution of nocturnal activity patterns, which are influenced by environmental conditions. In the present study, abiotic factors were investigated to comprehend the influence on the flight patterns and identify the sex ratio of beetles from this subfamily. A study was conducted at Campo de Instrução Marechal Newton Cavalcanti in northeastern Brazil between December 2010 and November 2011. Thirteen species of Dynastinae were identified, most of which were from the genus Cyclocephala. Abundance and richness were greater in the dry season. Six species exhibited peak flight activity at specific periods of the night. More females than males were recorded for Cyclocephala distincta and C. paraguayensis. The present findings suggest that rainfall reduces the flight activity of these beetles and different time schedules may be related to mating behavior, foraging behavior and the avoidance of interspecific resource competition.

Dung beetle (Coleoptera, Scarabaeidae) assemblage of a highly fragmented landscape of Atlantic forest: from small to the largest fragments of northeastern Brazilian region

Human activities in tropical forests are the main causes of forest fragmentation. According to historical factor in deforestation processes, forest remnants exhibit different sizes and shapes. The aim of the present study was to evaluate the dung beetle assemblage on fragments of different degree of sizes. Sampling was performed during rainy and dry season of 2010 in six fragments of Atlantic forest, using pitfall traps baited with excrement and carrion. Also, we used two larger fragments as control. We used General Linear Models to determine whether the fragments presented distinguished dung beetle abundance and richness. Analysis of Similarities and Non-Metric Multidimensional Scaling were used to determine whether the dung beetle assemblage was grouped according to species composition. A total of 3352 individuals were collected and 19 species were identified in the six fragments sampled. Dung beetle abundance exhibited a shift according to fragment size; however, richness did not change among fragments evaluated. Also, fragments sampled and the two controls exhibited distinct species composition. The distinction on abundance of dung beetles among fragments may be related to different amount of resource available in each one. It is likely that the dung beetle richness did not distinguish among the different fragments due to the even distribution of the mammal communities in these patches, and consequent equal dung diversity. We conclude that larger fragments encompass higher abundance of dung beetle and distinct species. However, for a clearer understanding of effects of fragmentation on dung beetles in Atlantic forest, studies evaluating narrower variations of larger fragments should be conducted.

Biology and management of the masked chafer Cyclocephala distincta Burmeister (Melolonthidae, Dynastinae, Cyclocephalini)

Adults of Cyclocephala distincta are flower visitors of Neotropical palms (Arecaceae) and commonly found in the Atlantic Forest of Pernambuco, Brazil. Males and females were collected in the wild and subjected to captive rearing and breeding. The egg hatching rate, the life cycle, longevity of immatures and adults, and oviposition parameters in captivity were analyzed. The average duration of the life cycle of C. distincta was 108.2 days (n = 45). The egg stage lasted on average 10.9 days, and the egg-hatching rate was 73.9%. The immature stage lasted on average 93.4 days. The larvae stage exhibited negative phototaxis, and the size of their head capsules increased at a constant rate of 1.6 between instars, following Dyar's rule. The average duration of the first instar was 24.8 days (n = 88), whereas the second and third instars lasted for 17.2 (n = 76) and 40.4 (n = 74) days respectively, and survival rates were 21.6%, 86.4% and 97.4%. The pre-pupal stage was recorded, and pupal chambers were built before pupation. The average number of eggs laid per female was 15.5, the total reproductive period lasted for 3.3 days, and the total fertility was 81.2%. Adults that emerged in captivity exhibited an average longevity of 18.9 days. Adult C. distincta exhibited thanatosis behavior upon manipulation, a strategy observed for the first time in Cyclocephala.

What is the importance of open habitat in a predominantly closed forest area to the dung beetle (Coleoptera, Scarabaeinae) assemblage?

What is the importance of open habitat in a predominantly closed forest to the dung beetle assemblage? The Atlantic Forest in Brazil is one of the most highly disturbed ecosystems and is mainly represented by fragmented areas. However, in places where human disturbances have ceased, certain areas are showing a natural regeneration pattern. The aim of the present study was to determine how the dung beetle assemblage responds to distinct habitat structures in a fragment of Atlantic Forest. For such, open and closed forest areas were sampled in a fragment of the Atlantic Forest in the northeastern region of Brazil. Pitfall traps baited with excrement and carrion were used to collect the beetles. A total of 7,267 individuals belonging to 35 species were captured. Canthon chalybaeus and C. mutabilis were restricted to open areas. Nearly 90% of the individuals of C. aff. simulans and Deltochilum aff. irroratum were identified in these areas. A higher percentage (> 50%) of Canthon staigi, Dichotomius aff. depressicolis and D. aff. sericeus occurred in closed areas. Abundance differed between areas, with higher values in closed areas. Richness was not influenced by the habitat structure. NMDS ordination exhibited the segregation of areas and ANOSIM confirmed that this variable explained the assemblage of dung beetle species. The findings of the present study validate that open areas are associated to more restrictive conditions, limiting a higher abundance of dung beetle. Although situated near preserved fragments, the studied open areas increase the heterogeneity of the general landscape.

Entomofauna associated to fruits and seeds of two species of Enterolobium Mart. (Leguminosae): harm or benefit?

Entomofauna associated to fruits and seeds of two species of Enterolobium Mart. (Leguminosae): Harm or benefit? The aims of the present study were to identify the entomofauna associated to the fruits and seeds of Enterolobium contortisiliquum (Vell.) Morong and Enterolobium timbouva Mart. (Leguminosae), as well as to determine relationships among insects and the possible harm and/or benefit stemming from these associations. Fruit infestation was evaluated and the insects were identified. Seed consumption (%) and the germination of predated seeds (%) were determined. The fruits of E. contortisiliquum exhibited a high percentage of infestation (91%). The most representative species in the fruits were Lophopoeum timbouvae Lameere, 1884, Merobruchus bicoloripes (Pic, 1930) and Stator limbatus (Horn, 1873). In the fruits of E. timbouva, only one species was found (S. limbatus). E. contortisiliquum seed consumption was proportionately higher (55.2%) to that of E. timbouva (15%). The germination of predated seeds from E. contortisiliquum was null, whereas 40% of predated seeds from E. timbouva germinated.

First report of Oxysternon silenus Castelnau (Scarabaeidae, Scarabaeinae, Phanaeini) in the Brazilian Atlantic Forest

First report of Oxysternon silenus Castelnau (Scarabaeidae, Scarabaeinae, Phanaeini) in the Brazilian Atlantic Forest. This is the first record of Oxysternon silenus in the Brazilian Atlantic Forest. Specimens were collected in the Serra Grande landscape, municipality of Ibateguara, in Alagoas State. The samples were done from August 17 to 19, 2007 with pitfall traps. Before the present study, Oxysternon silenus had been reported predominantly in Amazonian region. The finding of this species corroborates the hypothesis of the biogeographical relationships between the Amazon Rainforest and the Atlantic Forest.

Primeiro relato de Oxysternon silenus Castelnau (Scarabaeidae, Scarabaeinae, Phanaeini) na Mata Atlântica brasileira. Esse é o primeiro registro de Oxysternon silenus na Mata Atlântica brasileira. Os espécimes foram coletados em Serra Grande, município de Ibateguara, Alagoas. As coletas foram realizadas de 17 a 19 de agosto de 2007 com a utilização de armadilhas do tipo pitfall. Antes do presente estudo, Oxysternon silenus tinha sido reportada apenas na região Amazônica. O encontro dessa espécie reforça a hipótese das relações biogeográficas entre a Amazônia e a Mata Atlântica.

Resposta da comunidade de formigas aos atributos dos fragmentos e da vegetação em uma paisagem da Floresta Atlântica nordestina / Response of the ant community to attributes of fragments and vegetation in a northeastern Atlantic Rain Forest area, Brazil

The objective of this study was to determine the effects of forest fragmentation on ant richness in a landscape of Atlantic Forest in Northeast Brazil. More specifically, the ant richness was related to the attributes of fragments (area and distance from the fragment central point to the edge), landscape (forest cover surrounding the fragments), and tree community (plant density, richness, and percentage of shade tolerant species). The surveys were carried out in 19 fragments located in Alagoas State from October 2007 to March 2008. Samples were collected through a 300 m transect established in the center of each fragment, where 30 1-m² leaf litter samples were collected at 10 m intervals. A total of 146 ant species was collected, which belonged to 42 genera, 24 tribes and nine subfamilies. The attributes of fragments and landscape did not influence ant richness. On the other hand, tree density explained ca. 23 percent of ant richness. In relation to functional groups, both density and richness of trees explained the richness of general myrmicines (the whole model explained ca. 42 percent of the variation in this group) and percentage of shade tolerant trees explained the richness of specialist predator ants (30 percent for the whole model). These results indicate that ant fauna is more influenced by vegetation integrity than by fragment size, distance to edge or forest cover surrounding fragments.

Tityus stigmurus (Thorell, 1876) (Scorpiones; Buthidae): response to chemical control and understanding of scorpionism among the population / Tityus stigmurus (Thorell, 1876) (Scorpiones; Buthidae): resposta ao controle químico e entendimento da população sobre escorpionismo

In this study, the events following application of the insecticide Demand 2.5 concentrated solution (CS) in the field, to control Tityus stigmurus, were investigated. Data on attitudes and practices relating to scorpionism were collected using a questionnaire. During the months of May to July 2005, 69 premises were monitored on different days following insecticide treatment, focusing on scorpion frequency and mortality. According to the results, 42 percent of the premises showed scorpion incidence, with an average of three specimens per house. The highest incidence was recorded during the first week following the treatment. Only 7 percent of the specimens were found dead. Most (72 percent) of the population showed knowledge about prevention and control measures. Despite this, 100 percent of the premises presented breeding sites, mainly in debris (79.7 percent). These results indicate that the scorpion control method used by health agents during this investigation was not efficient, and the results suggest that the method may have had a dispersive effect on these animals.

Neste trabalho investigou-se os eventos ocorridos após a aplicação do inseticida Demand 2,5 solução concentrada (CS) em campo para controle de Tytius stigmurus. Dados sobre atitudes e práticas relacionados ao escorpionismo foram coletados usando um questionário. Durante os meses de maio a julho/2005, 69 imóveis foram monitorados em diferentes dias após o tratamento com inseticida, focando a freqüência e mortalidade de escorpiões. Segundo os resultados, 42 por cento dos imóveis apresentaram incidência escorpiônica com uma média de três indivíduos/casa. O maior índice de incidência foi registrado na primeira semana após o tratamento. Apenas 7 por cento dos espécimes foram encontrados mortos. A maioria (72 por cento) da população demonstrou conhecer as medidas de prevenção e controle. Apesar disso, 100 por cento das residências apresentaram criadouros, principalmente entulhos (79,7 por cento). Esses resultados indicam que o método para controle escorpiônico usado pelos agentes de saúde, durante a pesquisa não foi eficiente, sugerindo um possível efeito dispersor sobre o animal.

Distribution pattern of herbivorous insects in a remnant of Brazilian Atlantic Forest

Neste estudo foram selecionados três habitats que correspondem a um gradiente de proporção de plantas pioneiras bordas, trilhas no interior de floresta e áreas nucleares de floresta e descreveu-se a assembléia de insetos herbívoros neles presente. Foram testadas cinco hipóteses sobre a composição da assembléia: (1) as ordens de insetos herbívoros apresentam diferentes distribuições de abundância e de riqueza entre os habitats, (2) a similaridade de espécies é menor entre habitats do que dentro dos habitats, (3) a abundância é maior em borda, seguida de trilha e interior, (4) a riqueza é maior no interior, seguido de trilha e borda e (5) existe diferença na abundância e riqueza de insetos herbívoros entre as estações. Os insetos foram amostrados durante novembro de 2000 e maio de 2001 através da inspeção das plantas ao longo de 10 transectos de 1000 m3 por habitat, cinco em cada estação. Foram amostrados 1.424 indivíduos de 367 espécies de seis ordens. Orthoptera e Coleoptera foram os herbívoros mais abundantes em borda e interior da floresta, respectivamente. Coleoptera apresentou a maior riqueza em borda de floresta enquanto Lepidoptera no interior. A fauna amostrada foi mais similar dentro de um mesmo habitat que entre os habitats. A abundância, riqueza e diversidade foram maiores na borda que em trilha e interior em ambas estações. Sugere-se que a baixa riqueza no interior da floresta se deva à perda de herbívoros especializados em plantas de floresta madura, as quais estariam também localmente extintas na área estudada.

In this study we selected three habitats that correspond to a light gradient, andconsequently a proportion of pioneer plant species gradient – edges, trails and forest core – and described their herbivorous insect assemblage. We tested five hypothesis about the herbivorous assemblage: (1) there is a different distribution of abundance and richness of order between habitats, (2) species similarity between habitats is smaller than within habitat, (3) in forest edge the herbivores are more abundant than in trails and interior of the forest, (4) in nuclear areas herbivore richness and diversity are higher than in the trails and edge, and (5) the abundance and richness of herbivores are different between seasons. Herbivorous were sampled during November 2000 - May 2001 by scanning the plants in ten 1,000-m3 transects per habitat, five per season. We sampled 1,424 adult individuals from 367 species of six orders. Orthoptera and Coleoptera were the most abundant herbivores in the edge and interior, respectively. Coleoptera showed the highest species diversity in the forest edge, while Lepidoptera was in the interior. The similarity of the fauna between habitats was smaller than within habitats. The values of abundance, richness and diversity in the edge were higher than those of trails and interior for both seasons. We suggest that the low richness of herbivores in the interior of the forest is due to a reduction of specialist groups associated to plant species characteristic of mature forest, which are locally extinct in the study area.