Community structure and specialization in fig wasps (Hymenoptera: Chalcidoidea) in a region of Cerrado

ABSTRACT Ficus inflorescences host a species-rich chalcid wasp community, including pollinating fig wasps (Agaonidae: Tetrapusinae, Kradibiinae, and Agaoninae) and several species of non-pollinating fig wasps (NPFW), that show several life-history strategies, including gall-inducers, kleptoparasites (i. e. inquilines), and parasitoids. We analyzed the structure and degree of specialization of the fig wasp community associated with Ficus inflorescences in urbanized areas, agroecosystems, and on the edge of forest fragments in the state of Goiás (Brazil). We sampled 34 wasp species in four native Ficus tree species, from which four wasp species occurred in more than one host. Neotropical fig pollinators (Pegoscapus and Tetrapus) were the most abundant species, and they were host-specific, although two pollinator species were associated with Ficus obtusifolia. The Jaccard similarity index was higher in samples of fig wasps collected in the same host, indicating that the community composition was specific to each host species. Community structure indices indicate a specialized structure with low connectance, high bidimensional Shannon H2' and low partner diversity. The communities present a modular web structure in which modules were represented by each host and its associated insect species. These results indicate that the fig wasp communities analyzed are highly specialized, despite a few not strictly host-specific species.

Effect of patch size of the exotic host plant Calotropis procera (Apocynaceae) on herbivory

Abstract Calotropis procera is a xerophytic perennial milkweed shrub native to Asia and Africa, which currently is also widely distributed throughout the Brazilian Caatinga. C. procera is well defended against herbivores, especially with latex and toxic steroidal cardenolides. The goal of this study was to evaluate how patch size of this exotic host plant affect insect herbivory. Eight patches were selected containing a varied number of C. procera individuals (5, 8, 29, 31, 55, 79, 116, and 172 individuals/patch) in the Caatinga. Patches were divided into four categories according to the number of C. procera individuals: very small (5 and 8), small (29 and 31), intermediate (55 and 79), and large (116 and 172). The percentage of herbivory was greater in patch categories with more individuals. Among the herbivorous insects associated with C. procera, larvae of Danaus spp. (Lepidoptera: Nymphalidae) were commonly observed feeding on all patches. These herbivores present specialized behaviors to circumvent the presence of latex on the host leaves. Adult Danaus spp. females probably had higher probability to find large patches of C. procera, leaving a greater abundance of eggs and, consequently, increasing the herbivory by their larvae in these patches. In contrast to immigration tendency, emigration from large patches may be lower, because there is a higher probability of finding resources (e. g. suitable C. procera leaves) inside large patches compared with small patches. We conclude that patch size of the host plant C. procera is a major factor affecting herbivory.

Infestation of Mangroves by the Invasive Moth Hyblaea puera (Cramer, 1777)(Lepidoptera: Hyblaeidae)

Abstract We report the first known infestation of mangroves by the invasive moth Hyblaea puera in Paraná, Southern Brazil. The infestation caused massive defoliation of Avicennia schaueriana trees, affecting approximately 20,000 hectares of mangroves. We discuss the implications for conservation and management, focusing on protected areas, the ecology of mangroves, and local livelihoods.

Insect galls from Córdoba, Argentina: a case where stem galls predomínate / Agallas de insectos en Córdoba, Argentina: un caso en el que predominan las agallas caulinares

Abstract Galls are structures produced by plants in response to the activity of several types of organisms. Gall-inducing species have a close relationship with their host plant, as their habitat is largely restricted to the gall and the plant organ in which it develops. All plant organs are susceptible to gall induction by insects, the leaves being the most vulnerable. Knowledge about interactions between gall-inducing insects and plants is fragmented and incomplete in Argentina. In this study, we completed an inventory of galls induced by insects on plants in Córdoba (central Argentina) using information from field surveys and a review of the literature. We also focused on the frequency of plant-insect taxonomic associations and plant organs most commonly attacked by gall-inducing insects. Field surveys were performed systematically in 26 sites of Chaco Serrano, which were visited five times in two consecutive years, and in 17 sites of the province, which were sampled one or two times each. A comprehensive literature search of electronic and conventional databases was also conducted to complete the inventory. A total of 99 gall morphospecies on 58 plant species (21 families and 44 genera) were recorded through both field surveys and a literature review, enlarging the list of species available for the region by almost 50 %. Asteraceae and Fabaceae were the plant families most attacked by galling insects, in partial concordance with the most species-rich plant families in the region. Diptera, particularly the family Cecidomyiidae, was the most species-rich group in the community of galling insects, which is in agreement with different studies across the globe. Baccharis was the genus displaying the highest number of gall morphotypes, followed by Acacia, Condalia, Geoffroea, Prosopis and Schinus. Almost 60 % of the morphotypes were stem galls, a pattern uncommon in the literature. Fusiform and globoid-shaped galls were predominant. Our study highlights the scarce knowledge there is about the interactions between plants and gall-inducing insects in Argentina, particularly those involving species of Cecidomyiidae, with more than 30 undescribed species. Possible mechanisms involved in the predominance of stem galls in central Argentina are discussed. Rev. Biol. Trop. 66(3): 1135-1148. Epub 2018 September 01.

Resumen Las agallas son estructuras producidas por las plantas en respuesta a la actividad de diversos tipos de organismos, los cuales establecen una estrecha relación con sus especies hospedantes, ya que su hábitat está restringido en gran medida a la agalla y al órgano vegetal donde la agalla se desarrolla. Todos los órganos vegetales son susceptibles a la inducción de agallas por insectos, siendo las hojas los más frecuentemente atacados. En Argentina, el conocimiento de estas interacciones es fragmentando e incompleto. En el presente estudio, se realizó un inventario de agallas inducidas por insectos utilizando información obtenida de muestreos a campo y revisión bibliográfica. También nos enfocamos en las asociaciones taxonómicas insecto-planta más frecuentes y en los órganos vegetales más atacados por los insectos cecidógenos. Se realizaron muestreos a campo en 26 sitios localizados en el Chaco Serrano, que fueron visitados cinco veces en dos años consecutivos y en otros 17 sitios, distribuidos en la provincia de Córdoba, que fueron visitados una o dos veces. Además se realizó una exhaustiva revisión bibliográfica en bases de datos electrónicas (disponibles en internet) y convencionales. Un total de 99 agallas en 58 especies vegetales (21 familias y 44 géneros) fueron registradas a través de los muestreos en el campo y la revisión bibliográfica, ampliando el número de interacciones previamente conocidas en al menos un 50 %. Las familias vegetales más atacadas fueron Asteraceae y Fabaceae, coincidiendo con las familias vegetales más diversas de la región. La familia Cecidomyiidae (Diptera) presentó el mayor número de especies, en concordancia con diversos estudios alrededor del mundo. Baccharis fue el género vegetal que mayor número de morfotipos de agallas albergó, seguido por Acacia, Condalia, Geoffroea, Prosopis y Schinus. Al menos el 60 % de morfotipos registrados se presentaron en tallos, un patrón poco común en la bibliografía. Las formas predominantes fueron fusiforme y globoide. Nuestra investigación revela el escaso conocimiento sobre la comunidad de insectos cecidógenos y sus agallas en Argentina, particularmente de las inducidas por especies de la familia Cecidomyiidae, con más de 30 especies aún no descritas. Se discuten posibles mecanismos involucrados en la predominancia de agallas caulinares en el centro de Argentina.

Insect Galls of the Parque Nacional do Itatiaia (Southeast Region, Brazil)

ABSTRACT The Parque Nacional do Itatiaia (PNI) (Brazilian Southeast Region) was surveyed monthly for insect galls from February/2014 to December/ 2015. A total of 432 gall morphotypes were found. This number places the PNI as the richest Atlantic forest area in number of gall morphotypes. The galls were found on 47 plant families. Among them, Asteraceae were pointed out as the superhost. The gall richness in the lower part of the PNI is higher than that of the plateau. The insect galls were found in 154 native, 56 endemic and only one exotic plant species. Concerning the conservational status, the host plants include two vulnerable species with three morphotypes together. Several new botanical records were reported. Leaves were the most galled plant organ, followed by stems. Globoid, green, glabrous and one-chambered galls were the most frequent. Cecidomyiidae were the most common gallers. Parasitoids, successors and inquilines composed the associated fauna.

Seed predation food web, nutrient availability, and impact on the seed germination of Senegalia tenuifolia (Fabaceae) / Red alimentaria de depredación de semillas, disponibilidad de nutrientes e impacto sobre la germinación de las semillas de Senegalia tenuifolia (Fabaceae)

Abstract:Food web studies, which include qualitative and quantitative information about species interactions for all trophic levels in a specific community, are important tools to characterize the community structure, and to understand the role of species interaction in natural communities. With this aim, we collected fruits of Senegalia tenuifolia from a total of nine sites from three different areas in Minas Gerais, from June to August 2011. Fruits were collected and taken to the laboratory in special containers, to allow insect development and description. And then, we characterized the food web of insects associated with these seeds, and described interactions between these organisms and the host plant, and assessed the impact of insect attacks on seed germination with an experiment under controlled conditions. Additionally, we estimated the available NPK content and the Carbon:Nitrogen ratio in both fruits and seeds. In S. tenuifolia seeds, we have found 937 associated insects of 15 species structured in four trophic levels. We found two Bruchinae seed-feeders species: Merobruchus terani and Stator maculatopygus. We also have observed the seed-feeding hymenopteran species Allorhogas sp. 1 and Prodecatoma sp. 1, and hymenopteran parasitoids species such as Eupelmus sp.1, Lyrcus sp.1, Eurytoma sp.1, Horismenu s sp.1, Chelonus sp.1, Aprostocetus sp.1, Eiphosoma sp.1 and an unidentified Pteromalinae. Considering quantitative food web metrics, our data have suggested low values of generality and high values of trophic vulnerability, besides others, which demonstrated how species interactions are specialized. The impact of seed-feeding insects on seeds was found severe and prevented their germination. Lastly, seeds contained higher NPK content than fruits. In conclusion, the seed predation food web supported by S. tenuifolia has depicted two different features: specialized species interactions, considering parasitoids and seed-feeding species, and, generalized species interactions, considering host-plant and seed-feeding species. Indeed, seeds are resources with high nutrient concentration supporting a rich and complex food web. Finally, S. tenuifolia seeds are directly impacted by seed-feeding insects, preventing them from germination, which could result in a negative effect on host-plant population.

Resumen:Estudios de redes alimentarias, que incluyen información cualitativa y cuantitativa sobre las interacciones entre especies para todos los niveles tróficos en una comunidad específica, son herramientas importantes para caracterizar la estructura de la comunidad, y para comprender el papel de la interacción de las especies en las comunidades naturales. Con este objetivo, se recolectaron frutos de Senegalia tenuifolia de un total de nueve sitios de tres áreas diferentes, en Minas Gerais, entre junio y agosto 2011. Los frutos fueron recolectados y llevados al laboratorio en contenedores especiales, para permitir el desarrollo y descripción del insecto. Luego, se caracterizó la red alimentaria de los insectos asociados a estas semillas, se describieron las interacciones entre estos organismos y la planta hospedera, y se evaluó el impacto del ataque de insectos en la germinación de semillas mediante un experimento en condiciones controladas. Además, se estimó el contenido de NPK y la relación carbono:nitrógeno en frutos y en semillas. En semillas de S. tenuifolia, se encontraron 937 insectos de 15 especies estructuradas en cuatro niveles tróficos. Se encontraron dos especies de Bruchinae que se alimentan de semillas: Merobruchus terani y Stator maculatopygus. También se observaron especies de himenópteros que se alimentan de semillas: Allorhogas sp. 1 y Prodecatoma sp. 1, y especies de himenópteros parasitoides como: Eupelmus sp.1, Lyrcus sp.1, Eurytoma sp.1, Horismenus sp.1, Chelonus sp.1, Aprostocetus sp.1, Eiphosoma sp.1 y un Pteromalinae no identificado. Nuestros datos sugieren valores bajos de generalidad trófica y valores altos de vulnerabilidad trófica, además de otros, lo que demuestra cómo las interacciones entre especies son especializadas. El impacto en las semillas de los insectos que se alimentan de estas es severo e impidió su germinación. Por último, las semillas tenían un mayor contenido de NPK que los frutos. En conclusión, la red alimentaria de depredación de semillas con S. tenuifolia tiene dos características: interacciones de especies especializadas, considerando parasitoides y especies comedoras de semillas, e interacciones generalizadas entre especies, teniendo en cuenta la planta hospedera y las especies comedoras de semillas. De hecho, las semillas son recursos con alta concentración de nutrientes que proveen una rica y compleja red trófica. Por último, las semillas de S. tenuifolia se ven directamente afectadas por los insectos que se alimentan de semillas, que les impide la germinación, lo que podría resultar en un efecto negativo en la población planta-hospedero.

Lipophilic metabolite profiling of maize and sorghum seeds and seedlings, and their pest spotted stem borer larvae: A standardized GC-MS based approach.

In order to better understand the biochemical interactions and to identify new biomarkers for plant resistance against insects, we proposed a suitable lipophilic profiling method for insects and their host plants. The critical components of GC-MS based analysis are: sample amount, extraction, derivatization, temperature gradient, run time, and identification of peaks. For lipophilic metabolite profiling of maize and sorghum, and their insect pest, spotted stem borer larvae, we recommend 100 mg sample weight for seeds and insect samples (whole insect body), and 200 mg for seedlings. Maize and sorghum seeds required less time for fat extraction in comparison to their seedlings and the pest fed on these seedlings. GC-MS was standardized for better separation and intensity of peaks using different temperature gradients in the range of 180-300 C. A total of 48 lipophilic compounds encompassing various classes based on their functional groups such as fatty acids, fatty alcohols, hydrocarbons, sterols and terpenoids, vitamin derivative, etc. were separated in the seedlings (30), seeds (14), and the pest (26) in the retention time range of 3.22 to 29.41 min. This method could be useful to study nutritional aspects of different field crops in relation to various stresses apart from the analysis of lipophilic compounds for better understanding of insect-plant interactions.

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.

Borboletas (Lepidoptera: Papilionoidea e Hesperioidea) de um parque urbano em Belo Horizonte, Minas Gerais, Brasil / Butterflies (Lepidoptera: Papilionoidea and Hesperioidea) from an urban park in Belo Horizonte, Minas Gerais State, Brazil

Fragmentos urbanos de mata, como parques e praças, oferecem recursos alimentares, sobretudo abrigo e condições favoráveis para a permanência de borboletas. Este estudo fornece um inventário de borboletas e também a observação das plantas visitadas por indivíduos adultos em um pequeno parque urbano, Parque Municipal Américo Renê Giannetti, Belo Horizonte, estado de Minas Gerais. Amostrou-se uma área de 18,2 ha no período de dezembro/2006 à dezembro/2007, com o auxilio de rede entomológica e armadilhas com frutos fermentados. Foram registrados 165 indivíduos de 78 espécies, distribuídos nas seguintes famílias: Nymphalidae - 46 spp., Hesperiidae - 10 spp., Lycaenidae - sete spp., Pieridae - sete spp., Riodinidae - cinco spp. e Papilionidae - três spp. Entre as plantas visitadas observou-se que a com maior atratividade foi Lantana camara (Verbenaceae), um arbusto com flores de cores vibrantes, destacada como fonte usual de néctar e pólen. As borboletas encontradas indicaram a importância da manutenção de áreas verdes urbanas, proporcionando condições favoráveis para a permanência de borboletas, mesmo em ambientes antrópicos.

Urban forest fragments, such as parks and squares provide food resources, shelter, and favorable conditions for the maintenance of butterflies. This study provides an inventory of butterflies and observations of plants visited by adults in a small urban park, the Américo Renê Giannetti Municipal city park, Belo Horizonte, Minas Gerais State. We sampled an area of 18.2 ha from December 2006 to December 2007 with entomological net and traps baited with fermented fruits. We recorded 165 individuals belonging to 78 species, as follows: 46 spp. of Nymphalidae; 10 spp. of Hesperiidae, seven spp. of Lycaenidae, seven spp. of Pieridae, five spp. of Riodinidae; and three species of Papilionidae. Between the plants visited the more attractive was Lantana camara (Verbenaceae), a shrub with flowers of vibrant colors and common source of nectar and pollen. The butterflies recorded show the importance of maintenance of urban green areas, providing favorable conditions for the permanence of butterflies, even in anthropic environments.

Aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) and their associations related to biological control in Brazil

This study evaluated the parasitoid-aphid-plant associations in Brazil with the objective of developing a useful research database for further studies of aphid parasitoid ecology and aphid management. The original material was obtained from collections made in Paraná, Rio Grande do Sul, Minas Gerais, and São Paulo states. The published information on the Aphidiinae in Brazil is revised. The general features of the target parasitoid fauna of Central and South America is summarized and promising biological control programs of some aphid species in Brazil is discussed.

Este trabalho avaliou as interações parasitóides-pulgão-planta no Brasil, com o objetivo de desenvolver um banco útil de dados para estudos subseqüentes em ecologia de parasitóides de afídeos e manejo de pulgões. O material original foi obtido de coletas nos estados do Paraná, Rio Grande do Sul, Minas Gerais e São Paulo, sendo revisadas as informações sobre Aphidiinae publicadas no Brasil. Foram também sumarizadas as caracteristicas gerais da fauna de parasitóides das Américas Central e do Sul e discutidos os programas potenciais de controle biológico de algumas espécies de pulgões no Brasil.

Levels of leaf Herbivory in Amazonian trees from different stages In forest regeneration

Leaves from 120 canopy trees and 60 understory tree saplings growing in primary and secondary forests near Manaus, Brazil, were collected for determination of standing levels of herbivory (percent leaf area lost). Overall, levels of herbivory on leaves of central Amazonian trees were low. About one quarter of the leaves examined (n = 855) had no damage at all. In most other Neotropical sites studied the mean percentage of herbivory was found to vary between 5.7 and 13.1%, whereas in Manaus it was only 3.1%. The data presented here support the contention that levels of herbivore damage are positively related to soil fertility. No significant difference was found in herbivory levels between canopy trees and understory saplings. Also, there was no difference in damage between leaves from pioneer and late successional trees. Field assays of preference, however, revealed that leaves from pioneer trees are more palatable to leaf-cutting ants (Atta laevigata). This effect was dependent upon leaf age, being observed in mature leaves, but not in young leaves. The greater rate of leaf production in secondary forests may be a factor accounting for the greater abundance of leaf-cutting ants in secondary compared to primary forests.

Folhas de 120 árvores do dossel e de 60 arvoretas do sub-bosque foram coletadas em florestas primárias e secundárias de terra-firme próximas a Manaus, para medição dos níveis de herbivoria (porcentagem da área foliar danificada por herbívoros). Os níveis de herbivoria foram baixos. Cerca de 25% das folhas examinadas (n = 855) não tinham dano algum. Na maioria das outras florestas Neotropicais estudadas a porcentagem média de herbivoria ficou entre 5,7 e 13,1%, enquanto em Manaus este valor foi de apenas 3,1%. Os dados apresentados aqui dão apoio a hipótese de que os níveis dc herbivoria são positivamente relacionados a fertilidade do solo. Não houve diferença no nível de herbivoria entre árvores do dossel e arvoretas do sub-bosque. Também, não encontrou-se diferença entre folhas de plantas pioneiras da mata secundária e aquelas de final de sucessão encontradas na mata primária. Testes de preferência, entretanto, mostraram que folhas das plantas pioneiras são mais palatáveis as saúvas (Atta laevigata). Este efeito foi dependente da idade foliar, tendo sido observado em folhas maduras mas não em folhas jovens. A maior taxa de produção de folhas na floresta secundária pode ser um dos fatores responsáveis pela maior abundância de saúvas na mata secundária do que na mata primária.