The concept of pollination syndromes has been widely questioned, since plant–pollinator interactions have proved to be more generalist than was previously thought. We examined whether the network of a tropical high‐altitude grassland contained groups of plants and pollinators that interact preferentially with each other. A general binary matrix was created. To assess the robustness of myophily, in all analyses we considered: 1) the whole network, 2) the network after the wasps were removed, and 3) the network after the flies were removed. For each network we evaluated whether: 1) the observed interactions were more related to syndromes than expected by chance, compared to an expected matrix; 2) there was a modular structure; 3) the modules found were more related to syndromes than expected by chance, compared to another expected matrix; 4) the syndromes were equally robust. For this analysis, the general matrix was subdivided into smaller matrices that included each pollination syndrome separately. To test the influence of the functional groups of pollinators and the phylogeny of plants, in addition to the general matrix, we also considered the first expected matrix, a quantitative functional group and a plant phylogeny matrix. The pollination syndromes determined the pattern of interactions in the network: 69% of the total interactions resulted from the functional group of pollinators predicted by the plant syndrome. The network showed greater modularity (13 modules) than expected by chance, mostly consisting of the expected functional groups of pollinators and plant syndromes. The modules were associated with pollination syndromes more than was predicted by chance. Most of the variation in interactions was explained by functional groups of pollinators or by plant syndromes. Plant phylogeny did not account for a significant amount of variation in the interactions. Our findings support the concept of pollination syndromes. However, the interactions were not equally predicted by different pollination syndromes, and the accuracy of the prediction was strongest for ornithophily and melittophily.

The theory of complex networks has been recently used to explain ecological associations between nurses and seedlings in plant facilitation systems. The structure of these networks is potentially affected by morphological, ecological and evolutionary factors that can determine the facilitative interactions. In the present study, we evaluate the role of the projected crown area of the nurse plant, the dispersal syndrome, the abundance and the phylogeny relationships with seedlings as drivers of network structure in facilitation networks. To test these parameters, we used an ecotonal forest-grassland system in southern Brazil that experienced historical forest expansion over the grassland in the last few centuries. In two State Parks, Guartelá (GUA) and Vila Velha (VVL), we sampled tree species (nurses and seedlings) along four transects parallel to the forest edge, with five sampling stations along each transect. Tree seedlings (height >0.3 m) were sampled below the nurse's crown (i.e. isolated woody plants, height >1.5 m) and over the grassland area. A total of 160 nurses and 358 seedlings were sampled. Seedling abundance and richness were greater below a nurse's crown than on open grassland. Nurse abundance was the best predictor of the observed interaction matrix. Probabilistic matrices based on abundance, abundance and phylogeny, and dominance were able to predict the observed nestedness values, and they were also closest to the observed connectance, although all of the probabilistic matrices have underestimated this property. Specialization was predicted by abundance and phylogeny, abundance and projected crown area drivers for VVL, and the abundance based models were closest to the predicted specialization for GUA. The result of a similar pattern in predictability between sites indicates that the influences of morphology and evolutionary and ecological processes over the facilitation interactions are equivalent on a regional scale. Woody plant abundance was a key factor for the facilitation networks, driving forest expansion along the subtropical forest-grassland ecotone.

O objetivo deste trabalho foi avaliar a flutuação populacional de Harmonia axyridis em árvores frutíferas, durante dois anos (2004-2006), relacioná-la a variáveis abióticas e avaliar sua influência sobre outros coccinelídeos predadores, em Ponta Grossa, PR. H. axyridis representou 38% dos Coccinellidae. Houve diferença significativa na freqüência relativa da espécie entre os anos de coleta, que passou de 0,20 para 0,67 de um ano ao outro. Houve correlação positiva significativa entre abundância de H. axyridis e temperatura média, nas plantas cítricas, e correlação negativa significativa entre abundância de H. axyridis e umidade relativa do ar, nas plantas não cítricas. H. axyridis exerce impacto negativo sobre as joaninhas locais.

The diversity of hoverflies in five different habitats of the Parque Estadual de Vila Velha, Ponta Grossa, Paraná , Brazil, from September 1999 to August 2002 was studied. These five areas had been exposed to various types of anthropogenic disturbance at different times, which resulted in different stages of plant succession. In total, 2,841 specimens of 151 species of Syrphidae were collected using malaise traps. The highest species richness and abundance were found at the edge of the forest (Forest Edge), whereas the lowest was found in the most conserved areas. Evenness values increased along the succession gradient. The accumulation curve of new occurrences of syrphid species nearly approached an asymptote starting on the third month of the third year. Estimates of syrphid species richness using different methods indicated that between 155 and 288 species are found in the study area, according the Michaelis–Menten and the Chao2 estimators, respectively. The richness and abundance of representatives of the subfamily Syrphinae were higher in more open areas, where herbaceous plants predominate. Nineteen hoverfly species can be considered as environmental indicators, as they were collected exclusively or mainly in one of the defined habitat types. The degree of opening of the vegetation seems to be the factor determining the distribution of Syrphidae species, a conclusion based on the finding that grassy clearings in Araucaria Forests had more species. Hence, we conclude that, to become established, Syrphidae communities need conserved mosaic landscapes.

No abstract

Ecological restoration has been increasingly considering biotic interactions. Different restoration strategies usually rely on different composition and abundance of plants with potential impact on the establishment of plant-pollinator interactions. We evaluated the restoration of plant-pollinator interaction networks in young restoration areas in the South Atlantic rainforest, Brazil. We assessed the relative contribution of two restoration strategies (natural regeneration vs. reforestation), geographic distance, plant composition, pollinator composition, abundance of flowers and insects, and plant-pollinator temporal overlap, that is, phenological coupling, to predict the establishment of pairwise interactions. We expected that restoration strategies would indirectly affect the patterns (identity and frequency) of pairwise interactions due to their influence on the processes driving interactions. We sampled monthly pollinators and the plants they visited on six reforestation sites and six natural regeneration sites during 20 months. We surveyed flower abundance in summer. We analyzed the relative contribution of each factor to predict the identity and frequency of pairwise interactions using structural equation modeling. Contrary to expectations, the restoration strategy did not predict interactions, probably because the sites under restoration were surrounded by natural and conserved landscapes. Since we found no effect of restoration strategies on plant composition, abundance, and phenological coupling, the restoration strategy did not predict interactions. Phenological coupling explained more than half of the interaction patterns, representing the best predictor of interactions followed by abundance and plant composition. Therefore, these predictors should be considered to select plant species in restoration projects that encompass interactions and pollination services.

RESUMO -Este trabalho teve como objetivo levantar informações sobre os padrões de composição faunística, estrutura da comunidade e sazonalidade de Chrysomelidae num pomar localizado na região dos Campos Gerais do Paraná. Durante cerca de dois anos de amostragem, foram coletados 3.661 coleópteros e, destes, 1.103 crisomelídeos, representando 30,1% dos besouros capturados. Eumolpinae e Galerucinae foram as duas subfamílias que apresentaram maior abundância e riqueza de espécies, sendo que as oito mais representativas no pomar foram: Eumolpinae sp. 7 e Eumolpinae sp. 15, Diabrotica speciosa, Iphimeis dives, Spintherophyta semiaurata, Colaspis sp. 1 e Colaspis sp. 2 e Syphrea sp. 1, representando 91,7% dos indivíduos coletados. Em relação às árvores frutíferas, observou-se que o maior número de insetos foi coletado em laranjeira e tangerineira; a laranjeira teve a maior riqueza de espécies, e o caquizeiro apresentou o maior índice de diversidade. A redução considerável de crisomelídeos no segundo ciclo anual demonstra que a família tem uma oscilação temporal acentuada. A primavera foi a estação de maior abundância nos dois anos de coleta, e os fatores meteorológicos não apresentaram correlação com a abundância de crisomelídeos. Termos para indexação: Análise faunística; sazonalidade; árvores frutíferas; bioecologia; flutuação de crisomelídeos; Campos Gerais do Paraná. CHRYSOMELIDS DIVERSITY AND SEASONAL OCCURRENCE (COLEOPTERA: CHRYSOMELIDAE) IN AN ORCHARD IN PONTA GROSSA DISTRICT, PARANÁ, BRAZILABSTRACT -This study aimed to obtain information about the fauna composition standards, community structure and Chrysomelidae seasonality in an orchard located in Campos Gerais region of Paraná. During the nearly two years of sampling, 3,361 coleopterous were collected, and among these coleopterous, 1,103 belonged to Chrysomelidae family, representing 30.1% of the captured beetles. Eumolpinae and Galerucinae subfamilies showed the biggest species abundance and richness, furthermore, the most representative to the orchard were: Eumolpinae sp. 7 and Eumolpinae sp. 15, Diabrotica speciosa, Iphimeis dives, Spintherophyta semiaurata, Colaspis sp. 1 and Colaspis sp. 2 and Syphrea sp. 1, representing 91.7% of the collected coleopterous. In relation to the fruit trees, it was observed that the biggest insect number was collected on the orange and tangerine trees; orange tree had the biggest species richness index and persimmon tree showed the biggest diversity index. There was a considerable reduction of the Chrysomelidae species on the second annual cycle, and this fact demonstrated that the family has a great temporal variation. Spring was the season with the largest abundance on two years of collection and the meteorological factors did not show any relation to the Chrysomelidae abundance.

Ecdysteroid titers, developmental landmarks and the presence of prominent amplifying regions (DNA puffs) have been compared during late larval to pupal development in four groups of Rhynchosciara americana larvae and in R. americana and Rhynchosciara milleri. Three prominent DNA puffs (B2, C3 and C8) expand and regress sequentially on the rising phase of the 20-hydroxyecdysone (20E) titer in R. americana as a firm, cellular cocoon is being constructed. A sharp rise in 20E coincides with the regression of these puffs. The shape of the 20E curve is similar in R. milleri, a species that does not construct a massive cocoon, but the behavior of certain DNA puffs and their temporal relationship to the curve differs. Regions corresponding to B2 and C3 can be identified in R. milleri by banding pattern similarity with R. americana chromosomes and, in the case of B2, by hybridization to an R. americana probe. A B2 puff appears in R. milleri as the 20E titer rises but remains small in all gland regions. A puff similar to the R. americana C3 puff occurs in posterior gland cells of R. milleri (C3(Rm)) after the B2 puff, but this site did not hybridize to R. americana C3 probes. C3(Rm) incorporated (3)H-thymidine above background, but showed less post-puff DNA accumulation than C3 of R. americana. R. americana C8 probes hybridized to a more distal region of the R. milleri C chromosome that did not appear to amplify or form a large puff. These differences can be related to developmental differences, in particular differences in cocoon construction between the two species.