Milton de Souza Mendonça

Spider Trait Assembly Patterns and Resilience under Fire-Induced Vegetation Change in South Brazilian Grasslands

Disturbances induce changes on habitat proprieties that may filter organisms functional traits thereby shaping the structure and interactions of many trophic levels. We tested if communities of predators with foraging traits dependent on habitat structure respond to environmental change through cascades affecting the functional traits of plants. We monitored the response of spider and plant communities to fire in South Brazilian Grasslands using pairs of burned and unburned plots. Spiders were determined to the family level and described in feeding behavioral and morphological traits measured on each individual. Life form and morphological traits were recorded for plant species. One month after fire the abundance of vegetation hunters and the mean size of the chelicera increased due to the presence of suitable feeding sites in the regrowing vegetation, but irregular web builders decreased due to the absence of microhabitats and dense foliage into which they build their webs. Six months after fire rosette-form plants with broader leaves increased, creating a favourable habitat for orb web builders which became more abundant, while graminoids and tall plants were reduced, resulting in a decrease of proper shelters and microclimate in soil surface to ground hunters which became less abundant. Hence, fire triggered changes in vegetation structure that lead both to trait-convergence and trait-divergence assembly patterns of spiders along gradients of plant biomass and functional diversity. Spider individuals occurring in more functionally diverse plant communities were more diverse in their traits probably because increased possibility of resource exploitation, following the habitat heterogeneity hypothesis. Finally, as an indication of resilience, after twelve months spider communities did not differ from those of unburned plots. Our findings show that functional traits provide a mechanistic understanding of the response of communities to environmental change, especially when more than one trophic level is considered.

Borboletas (Lepidoptera: Papilionoidea e Hesperioidea) ocorrentes em diferentes ambientes na Floresta Ombrófila Mista e nos Campos de Cima da Serra do Rio Grande do Sul, Brasil

Com o intuito de contribuir para o conhecimento das borboletas da Floresta Ombrofila Mista e Campos de Cima da Serra do Rio Grande do Sul foi elaborada uma listagem de especies da assembleia de borboletas da Floresta Nacional de Sao Francisco de Paula e entorno. Foram realizadas saidas bimestrais de marco de 2006 a maio de 2008 sendo selecionados seis ambientes: (i) mata nativa de Araucaria angustifolia, (ii) mata nativa mesclada com reflorestamento de Araucaria angustifolia, (iii) reflorestamento de Araucaria angustifolia de mata aberta, (iv) reflorestamento de Araucaria angustifolia de mata fechada, (v) reflorestamento de Pinus e (vi) campo de altitude nativo. Apos 674 horas-rede de amostragem foram registradas 277 especies e subespecies de borboletas, distribuidas em 9661 individuos, pertencentes a seis familias, sendo destas 139 novos registros para esta regiao dos Campos de Cima da Serra, 13 novas ocorrencias para o estado e seis especies raras ou indicadoras de ambiente preservado.

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil. Carabidae is composed mainly by ground-dwelling predator beetles. It is the fourth most diverse group within Coleoptera, but its diversity in the Neotropical region is understudied. Here we describe and analyze the diversity of carabid beetles in a region of subtropical rain forest dominated by Araucaria angustifolia with different landscapes. Three areas were chosen in an environmental integrity gradient: primary forests, secondary forests and old Pinus plantations. Pitfall traps were taken monthly, in a total of 14 samples per area. 1733 adult carabid beetles, belonging to 18 species, were sampled. There were differences in richness and abundance between the sampled areas. The total scores followed the same tendency: primary forests (14 species/747 individuals), secondary forests (13/631) and Pinus forests (10/355). An analysis of similarity shows differences in species composition, for both areas and seasons. Galerita lacordarei was the most abundant species for all samples and seasons. Carabid species show similar responses in accordance with habitat heterogeneity and disturbance. The abundance of Galerita lacordarei was influenced by temperature, for all sampled sites. Environmental changes affect the carabid assemblages and decrease diversity, possibly interfering in local dynamics. Seasonality patterns seem to indicate an increase in individual movement during summer, probably in search of resources. It is suggested that microhabitat patchiness is probably an important factor affecting carabid beetle diversity at small spatial scales.

Predation of Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae) By Androthrips ramachandrai (Thysanoptera: Phlaeothripidae)

ABSTRACT The galling thrips Gynaikothrips uzeli Zimmermann (Phlaeothripidae) has attained pest status by attacking the leaves of the weeping fig, Ficus benjamina. Another thrips species, Androthrips ramachandrai Karny (Phlaeothripidae), was recently reported feeding on G. uzeli immatures. Here we conducted choice tests with adults of A. ramachandrai to evaluate any preference for the immature stages of G. uzeli (egg, larva or pupa) in artificial arenas. Nochoice experiments were also conducted to measure the rate of feeding on each immature stage of the galling thrips by adults of A. ramachandrai in a period of 24 h. There was no significant preference by the predators for the different immature stages of G. uzeli, but adults consumed more eggs than larvae or pupae of the gall thrips. Here we discuss the predatory behavior of this thrips and its potential as a biological control agent against G. uzeli.

Diversity of Pentatomoidea (Hemiptera) in riparian forests of southern Brazil: taller forests, more bugs

Matas riparias sao partes importantes de qualquer ecossistema, especialmente aqueles com predominio de campos e savanas. No entanto, matas riparias na regiao sul do Brasil tem recebido pouca atencao. Este trabalho representa o primeiro estudo quantitativo sobre a diversidade de percevejos-do-mato (Hemiptera, Pentatomoidea) no bioma Pampa, a partir do levantamento em matas riparias na regiao do municipio de Bage, Rio Grande do Sul, Brasil. Os objetivos incluiram a caracterizacao taxonomica da fauna de percevejos-do-mato e a implementacao de estudo ecologico da diversidade desse grupo. Rede-de-varredura e guarda-chuva entomologico foram utilizados para amostrar arvores e arbustos em nove pontos ao longo de tres dias consecutivos, em marco de 2006. No total, 154 individuos de 32 especies de Pentatomoidea foram coletados, quase todas novos registros para a fauna local. Matas com dossel mais alto apresentaram maior abundância e riqueza de especies do que matas com dossel mais baixo. Das 32 especies coletadas, 11 foram singletons e quatro foram doubletons. Nao houve diferenca na composicao de especies nos dois tipos de ambientes amostrados. A associacao das especies mais abundantes com o bioma Pampa e discutida. Embora baseada em um inventario rapido da fauna local, os resultados encontrados adicionam informacoes biologicas importantes sobre a fauna de percevejos-do-mato do bioma Pampa, especialmente aquela associada as matas riparias.

Effect of the insecticide Lambda-cyhalothrin on rice spider populations in southern Brazil

The adverse effect that insecticides have on spider populations is of major concern since these predators are a component in the biological control of rice insect pest populations. This study was designed to determine the effect of the pyrethroid insecticide, Lambda-cyhalothrin, on spider populations in rice fields. Treatments consisted of plots treated once with the insecticide and untreated plots (control). Spiders were sampled four times per crop year over a two year period in each of three sites in the state of Rio Grande dol Sul, Brazil. Treatments were replicated four times. Sweep net sampling was conducted to sample the araneofauna. Overall 1,961 spiders were collected, with a predominance of juveniles over adults. Between treatments, there were significantly larger numbers of spiders and species richness in areas without insecticide. There were also significant differences among areas (sites) and among days after the insecticide application. Of the 12 recorded families, Araneidae and Tetragnathidae dominated, and were both strongly affected by insecticide application, decreasing more than 50% in those locations. Overall, 37 species were recorded (insecticide: 29; without: 26), eleven species were exclusive for rice without insecticide and eight for rice with insecticide. Alpaida veniliae (Keyserling, 1865) (n = 236) and Tetragnathaaff.jaculator (108) were the most abundant in both treatments, but with large decreases in abundance in rice with insecticide. Among guilds, the predominance was for orb weavers (67.3%) in all locations, but with much lower values for those spiders in rice with insecticide application. This study illustrates that the spider fauna in rice fields are adversely affected by the application of the insecticide Lambda-cyhalothrin.

Holopothrips molzi sp.n. (Thysanoptera, Phlaeothripidae): natural history and interactions in Myrtaceae galls

Holopothrips molzi sp. n. (Thysanoptera: Phlaeothripidae) is described from southern Brazil inducing leaf galls on Myrcia guianensis (Myrtaceae). Field observations revealed that the numbers of this thrips were highly variable within galls, and two other insect species were recorded living in these galls: Myrciathrips variabilis Cavalleri et al. (Phlaeothripidae) and an eulophid wasp (Hymenoptera). We investigated here if morphological traits of leaf and gall and abundance of the invader thrips were correlated with the gall inducers abundance. In order to determine the feeding habit and behaviour of M. variabilis and its interactions with the gall inducer we performed observations ad libitum and attack simulation tests on both thrips species to observe their response to possible invaders. Our results showed that leaf size is not related to H. molzi abundance, and gall size is relevant only when total numbers of both thrips species are considered. Myrciathrips variabilis was observed feeding on gall tissues, and no direct antagonistic interactions between the two thrips were recorded. The results of the behavioural tests simulating attacks were remarkably different in the two thrips species, indicating different strategies when threatened or disturbed. The interaction between the two thrips species is probably a case of inquilinism.

Comparing Vegetation Types and Anthropic Disturbance Levels in the Atlantic Forest: How do Pentatomoidea (Hemiptera: Heteroptera) Assemblages Respond?

ABSTRACT The Atlantic Forest (AF) is considered the most fragmented and endangered Brazilian biome. The diversity of phytophagous insects increases after disturbances in forests, and it was hypothesized the Pentatomidae can furnish ecologically reliable information in terms of diversity in response to the changes occurring in AF. Our aim was to quantify the response of assemblages of Pentatomoidea to gradient of human disturbance in two vegetation types of the AF—dense ombrophilous forest (DOF) and mixed ombrophilous forest (MOF). Twelve transects were grouped into environmental classes, namely open, intermediate, and closed. Overall, 1,017 pentatomoids were sampled, representing 64 species. The open environment was more abundant than closed environment, though it is expected that Pentatomoidea respond with increasing abundance when under light or moderate disturbance. The MOF was more abundant than DOF, and the composition differed between both of them. Given the differences in composition between MOF and DOF, abiotic variables are important factors acting as environmental filters for Pentatomoidea, not just directly on the insects, but probably also on the nutritional support of their host plants.

Oviposition behaviour of Gryon gallardoi (Hymenoptera, Scelionidae) on eggs of different ages of Spartocera dentiventris (Hemiptera, Coreidae)

The oviposition behaviour of Gryon gallardoi (Brethes, 1914) on eggs of Spartocera dentiventris Mendonca Jr. (Berg, 1884) of different ages (2, 3, 4, 5, 6, 7, 8 and 12 days) was investigated. Groups of 12 eggs of each age were exposed to single females of G. gallardoi, and the oviposition behaviour was recorded under a stereomicroscope for two hours. Ten replicates were used for each age. In order to identify the moment the parasitoid egg was released inside the host, 1-day old eggs of S. dentiventris were exposed to G. gallardoi females, and the oviposition was interrupted at intervals of 20, 40, 60, 80, 100, 120, 140 and 160s after ovipositor insertion had initiated. Five behavioural steps were recorded: drumming, ovipositor insertion, marking, walking and resting. The average drumming and ovipositor insertion times increased with the host age (P<0.01). Ovipositor insertion usually occurred next to the longitudinal extremities of the host eggs. Marking took on average 19.5 ± 0.7s, and as walking and resting, was not affected by host age. Self-parasitism behaviour was observed in only 13.8 ± 2.3% of the eggs, being more evident with increasing patch depletion (reduction in non-parasitized eggs in the egg group, P<0.01), again with no variation due to changes in host egg age. For all ages tested, self-parasitized host eggs were less frequently contacted and accepted than non-parasitized ones (P<0.01). The parasitoid egg was released 137.0 ± 3.7s after ovipositor insertion. Spartocera dentiventris egg condition can lead to parasitoid behavioural changes, especially during the process of host choice and discrimination.

Pentatomidae (Hemiptera: Heteroptera) in Herbaceous and Shrub Strata of Atlantic Forest Remnants in Northeastern Brazil

Abstract Most pentatomids are phytophagous, many of which are economically important crop pests. The family may also be a potentially important group to monitor the health of neotropical forests. However, there is a lack of biological inventories of Pentatomidae, especially in forest remnants of the Brazilian Atlantic forest. This is the first systematic survey of pentatomids reported in three Atlantic forest fragments in northeastern Brazil. In total, 997 individuals belonging to 38 species were recorded, some of which are considered economically important pests. Singletons and doubletons represented 45.9% of all species collected. The most abundant genera were Mormidea Amyot & Serville, 1843; Stictochilus Bergroth, 1918; Xynocoris Garbelotto & Campos 2014; and Edessa F., 1803. Species richness differed among fragments, with a richness gradient correlated with decreased urbanization and increased fragment size. The species abundance distribution fitted the logseries function but not the lognormal, in accordance with what is found for other assemblages in southern Brazil. Species composition also changed, in association with changes in temperature (revealed by the canonical correspondence analysis [CCA]), among fragments. Murici is one of the last remaining dense forests with high plant diversity in the region, having higher pentatomid species richness and a distinctive fauna. This first diversity study for Pentatomidae in fragments of tropical Atlantic Forest in northeastern Brazil reveals richness comparable with those from subtropical southern Brazil, with some species in common as well.