Natural history and morphology of the hoverfly Pseudomicrodon biluminiferus and its parasitic relationship with ants nesting in bromeliads.

The syrphid subfamily Microdontinae is characterized by myrmecophily of their immature stages, i.e., they develop in ant nests. Data on natural history of microdontines are scarce, especially in the Neotropics. Based on fieldwork in southern Brazil, this study provided new data on development and ecology of the hoverfly Pseudomicrodon biluminiferus (Hull) (Diptera: Syrphidae) as well as the first morphological descriptions of male genitalia, larvae, and pupa. Immature specimens were specifically found in colonies of the ant species Crematogaster limata Smith (Hymenoptera: Formicidae) found in rosettes of the bromeliad species Aechmea lindenii (E. Morren) Baker (Poales: Bromeliaceae) and A. nudicaulis (L.) Grisebach. Third instar larvae were observed preying on ant larvae, revealing the parasitic nature of P. biluminiferus. In this and several other aspects, the natural history of P. biluminiferus is similar to that of Holarctic microdontine species. Exceptions include: (i) indications that adults of P. biluminiferus outlast the winter months (in contrast to 3(rd)instar larvae in Holarctic species) and (ii) P. biluminiferus' relationship with bromeliads. The importance of bromeliads for this host-parasite system is evaluated in this paper. The single occurrence of another, unidentified microdontine species' pupae in a nest of the ant species Camponotus melanoticus Emery (Hymenoptera: Formicidae) is reported.

Jardins de formigas na Amazônia Central: um experimento de campo utilizando cupins vivos como iscas / Ants gardens in the Central Amazon: a field experiment using live termites as bait

Ant gardens are a special association type between ants and epiphytes, in which two or more ant species can share the same nest in a parabiotic relationship. This association that occurs in tropical forests is still poorly understood. The aim of this study was to evaluate ants gardens in the Central Amazon and to determine if ants identify and remove potential herbivores that are visiting the host tree of ants gardens occupied by the species Camponotus femoratus and Crematogaster levior. In this study, it was observed 42 trees occupied by ants gardens. In each tree it was inserted a termite as bait at different distances from the nest, the time of the termites' removal was recorded and it was observed if there was the need of assistance from other ants to perform the removal of the bait. The results revealed that both species examined the tree host to forage. During the capture of the bait, C. levior was more efficient to detect the termite, and it was not observed the need of recruits to carry it to the nest. In some cases, individuals of de C. femoratus identified the bait and individuals of C. levior carried to the nest. The relationship between the host tree and ants is beneficial to both of them, since the tree receives indirect protection against termites and gives support to the ants nest.(AU)

Jardins de formigas são um tipo especial de associação entre formigas e epífitas, em que duas ou mais espécies de formigas podem compartilhar o mesmo ninho por parabiose. Essa associação que ocorre em florestas tropicais ainda foi pouco estudada. O objetivo deste trabalho foi avaliar jardins de formigas na Amazônia Central determinando se as formigas identificam e removem potenciais herbívoros que estejam visitando as árvores hospedeiras de jardins de formigas ocupados pelas espécies Camponotus femoratus e Crematogaster levior. No estudo foram observadas 42 árvores contendo jardins de formigas. Em cada árvore foi colocado um cupim, como isca, a diferentes distâncias do ninho, contabilizado o tempo para sua remoção e observado se havia recrutamento de outras formigas para realizar a remoção da isca. Os resultados evidenciaram que ambas as espécies examinam as árvores hospedeiras para forragear. Durante a captura da isca, C. levior foi mais eficiente para detectar o cupim, não tendo sido observado recrutamento para carregá-lo ao ninho. Em alguns casos, indivíduos de C. femoratus identificaram a isca e indivíduos de C. levior a carregaram ao ninho. A relação entre árvore hospedeira e formigas beneficiam ambas, pois a árvore recebe proteção indireta contra cupins e fornece apoio para o ninho das formigas.(AU)

Jardins de formigas na Amazônia Central: um experimento de campo utilizando cupins vivos como iscas / Ants gardens in the Central Amazon: a field experiment using live termites as bait

Ant gardens are a special association type between ants and epiphytes, in which two or more ant species can share the same nest in a parabiotic relationship. This association that occurs in tropical forests is still poorly understood. The aim of this study was to evaluate ants gardens in the Central Amazon and to determine if ants identify and remove potential herbivores that are visiting the host tree of ants gardens occupied by the species Camponotus femoratus and Crematogaster levior. In this study, it was observed 42 trees occupied by ants gardens. In each tree it was inserted a termite as bait at different distances from the nest, the time of the termites' removal was recorded and it was observed if there was the need of assistance from other ants to perform the removal of the bait. The results revealed that both species examined the tree host to forage. During the capture of the bait, C. levior was more efficient to detect the termite, and it was not observed the need of recruits to carry it to the nest. In some cases, individuals of de C. femoratus identified the bait and individuals of C. levior carried to the nest. The relationship between the host tree and ants is beneficial to both of them, since the tree receives indirect protection against termites and gives support to the ants nest.

Jardins de formigas são um tipo especial de associação entre formigas e epífitas, em que duas ou mais espécies de formigas podem compartilhar o mesmo ninho por parabiose. Essa associação que ocorre em florestas tropicais ainda foi pouco estudada. O objetivo deste trabalho foi avaliar jardins de formigas na Amazônia Central determinando se as formigas identificam e removem potenciais herbívoros que estejam visitando as árvores hospedeiras de jardins de formigas ocupados pelas espécies Camponotus femoratus e Crematogaster levior. No estudo foram observadas 42 árvores contendo jardins de formigas. Em cada árvore foi colocado um cupim, como isca, a diferentes distâncias do ninho, contabilizado o tempo para sua remoção e observado se havia recrutamento de outras formigas para realizar a remoção da isca. Os resultados evidenciaram que ambas as espécies examinam as árvores hospedeiras para forragear. Durante a captura da isca, C. levior foi mais eficiente para detectar o cupim, não tendo sido observado recrutamento para carregá-lo ao ninho. Em alguns casos, indivíduos de C. femoratus identificaram a isca e indivíduos de C. levior a carregaram ao ninho. A relação entre árvore hospedeira e formigas beneficiam ambas, pois a árvore recebe proteção indireta contra cupins e fornece apoio para o ninho das formigas.

Actividad antibacterial de extractos de hormigas de los géneros Crematogaster y Solenopsis / Antibacterial activity extracts of the ant genera Crematogaster and Solenopsis

Uno de los principales problemas que enfrenta la comunidad científica en la actualidad, es la aparición cada vez más frecuente de cepas bacterianas patógenas resistentes a los antibióticos y antimicrobianos actuales, porque dichos gérmenes tienen la capacidad, bajo determinadas circunstancias, de hacerse inmunes a tales agentes químicos; por tanto, es necesaria la búsqueda de nuevos agentes antibacterianos. Para este propósito, una buena fuente puede provenir de los insectos sociales, los cuales han desarrollado como estrategia de supervivencia la producción de agentes bactericidas para proteger sus colonias. Este trabajo se centró en determinar si ciertas hormigas que se adaptaron a los ámbitos urbanos, tienen esta actividad. Para ello, se capturaron hormigas de los géneros Crematogaster sp. y Solenopsis sp., que se sometieron a procesos de extracción por maceración, obteniéndose extractos etanólicos totales, muy poco hidrosolubles, los cuales se evaluaron a diferentes concentraciones sobre cepas de bacterias Gram negativas (Klebsiella pneumoniae y Pseudomona aeruginosa) y Gram positivas (Bacillus subtilis spizizenii y Staphylococcus aureus), encontrando actividad inhibitoria al crecimiento en diferentes grados sobre todas ellas, incluyendo una S. aureus resistente a los antibióticos Amoxicilina/Ac. Clavulánico, Ampicilina/Sulbactam y Ceftriazona/Oxacilina; por tanto, estas especies se pueden clasificar como promisorias en la búsqueda de nuevos agentes antimicrobianos.

One of the main problems faced today by the scientific community is the increasingly frequent occurrence of pathogenic bacterial strains resistant to current antibiotics and antimicrobial, because these germs are able, under certain circumstances, to be immune to such chemicals, it is therefore necessary to pursue the search for new agents. For this purpose, a good source can come from social insects, which have developed as a survival strategy, the production of bactericidal agents to protect their colonies. The purpose of this work was to determine if certain ants that have adapted to urban environments, have antibacterial activity and to what extent. For this purpose, ants of the genus Crematogaster sp. and sp. Solenopsis were captured and subjected to extraction process by maceration, yielding total ethanolic extracts, very little soluble, which were evaluated at different concentrations on Gram negative bacteria strains (Klebsiella pneumoniae and Pseudomona aeruginosa) and Gram positive (Bacillus subtilis spizizenii and Staphylococcus aureus), finding growth inhibitory activity at different degrees over all strains, including an S. aureus one resistant to antibiotics Amoxicillin/Clavulanate, Ampicillin/Sulbactam, Ceftriaxone and Oxacillin; therefore, these species can be classified as promising in the search for new antimicrobial agents.

Antibacterial properties of contact defensive secretions in neotropical Crematogaster ants

Crematogaster ants use their contact venoms to compete with other ants. Although those venoms are used primarily as repellent and toxic secretions, they may have other functions. The present study aimed to test the antibacterial property of abdominal venom of three neotropical Crematogaster ant species (C. distans, C. pygmaea and C. rochai) against gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Enterococcus faecalis and Staphylococcus aureus) bacteria. Sterile filter paper was soaked with C. distans, C. pygmaea or C. rochai crude venom and placed on an agar dish that was inoculated with bacterial suspensions. The agar dish was incubated overnight at 37ºC and examined for zones of growth inhibition. For each tested venom and bacterial strain, three venom concentrations were used, with six replicates for each concentration: 1, 2 and 4 DGE (Dufour's gland equivalent). The venom of C. pygmaea, but not those of C. rochai and C. distans, inhibited the growth of all tested gram-positive and gram-negative bacterial strains. This is the first evidence of antibacterial properties of contact venoms in Crematogaster ants and it supports the claim that ant venoms are multifunctional. It is hypothesized that only C. pygmaea venom showed antibacterial activities due to its nesting habits.

Antibacterial properties of contact defensive secretions in neotropical Crematogaster ants

Crematogaster ants use their contact venoms to compete with other ants. Although those venoms are used primarily as repellent and toxic secretions, they may have other functions. The present study aimed to test the antibacterial property of abdominal venom of three neotropical Crematogaster ant species (C. distans, C. pygmaea and C. rochai) against gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Enterococcus faecalis and Staphylococcus aureus) bacteria. Sterile filter paper was soaked with C. distans, C. pygmaea or C. rochai crude venom and placed on an agar dish that was inoculated with bacterial suspensions. The agar dish was incubated overnight at 37ºC and examined for zones of growth inhibition. For each tested venom and bacterial strain, three venom concentrations were used, with six replicates for each concentration: 1, 2 and 4 DGE (Dufour's gland equivalent). The venom of C. pygmaea, but not those of C. rochai and C. distans, inhibited the growth of all tested gram-positive and gram-negative bacterial strains. This is the first evidence of antibacterial properties of contact venoms in Crematogaster ants and it supports the claim that ant venoms are multifunctional. It is hypothesized that only C. pygmaea venom showed antibacterial activities due to its nesting habits.

Distribución espacio-temporal de hormigas en un gradiente de luz, dentro de un sistema agroforestal de café, en Turrialba, Costa Rica

Temporal and spatial distribution of ants in a light gradient, in a coffee agroforestry system, Turrialba, Costa Rica. Shade trees are frequently present in coffee (Coffea arabica L.) agroforestry systems of Mesoamerica. These systems can harbor a rich entomofauna, including ants, which could be predators of key pests in these systems. However, the role of shade on the distribution and abundance of these ants is unknown, yet such knowledge could suggest guidelines for manipulating certain environmental conditions of their habitat, thereby achieving their conservation and increase. Therefore, we studied the effect of shade on the spatial and temporal distribution of three ant species (Solenopsis geminata, Pheidole radoszkowskii and Crematogaster curvispinosa) that may prey on the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae), and the mahogany shootborer, Hypsipyla grandella (Lepidoptera: Pyralidae). To do this, abundance was evaluated across a sun-shade gradient in a coffee plantation with four alternate plots (from pure sun to total shade) in Turrialba, Costa Rica. In the community that was studied 28 species of ants were collected, of which S. geminata was the dominant species (79 % of the total individuals), followed by P. radoszkowskii (16 %). S. geminata and C. curvispinosa preferred sunny areas, while P. radoszkowskii showed no defined preference. Likewise, with respect to location, S. geminata predominated in the soil, while P. radoszkowskii and C. curvispinosa predominated in coffee bushes. Rev. Biol. Trop. 55 (3-4): 943-956. Epub 2007 December, 28.

En los sistemas agroforestales de café (Coffea arabica L.) de Mesoamérica es frecuente la presencia de árboles de sombra. Estos sistemas pueden albergar una rica entomofauna, incluyendo hormigas, la cuales podrían depredar a plagas claves en dichos sistemas. Sin embargo, se desconoce el papel de la sombra sobre la distribución y abundancia de dichas hormigas, lo cual podría sugerir pautas para manipular ciertas condiciones de su hábitat y lograr su conservación e incremento. Por tanto, se estudió el efecto de la sombra sobre la distribución espacial y temporal de tres especies de hormigas (Solenopsis geminata, Pheidole radoszkowskii y Crematogaster curvispinosa) que pueden depredar a la broca del café, Hypothenemus hampei (Coleoptera: Scolytidae) y al barrenador de las meliáceas, Hypsipyla grandella. Para ello se evaluó su abundancia a través de un gradiente de sol-sombra en un cafetal con cuatro parcelas alternas (desde pleno sol hasta sombra total), en Turrialba, Costa Rica. En la comunidad estudiada se recolectaron 28 especies de hormigas, de las cuales S. geminata fue la dominante (79 % del total de individuos), seguida por P. radoszkowskii (16 %). S. geminata y C. curvispinosa prefirieron las áreas soleadas, mientras que P. radoszkowskii no mostró una preferencia definida. Asimismo, en cuanto a su ubicación, S. geminata predominó en el suelo, mientras que P. radoszkowskii y C. curvispinosa lo hicieron en los arbustos de café.

Artrópodes associados a mudas de pequizeiro

ABSTRACT The objective of this work was to evaluate the insects and the natural enemies of piquizeiro tree Caryocar brasiliense Camb. (Caryocaraceae) seedlings. A higher number of aphids Aphis gossypii (Glover) (Homoptera: Aphididae) and Crematogaster sp. ants (Hymenoptera: Formicidae) were detected on the abaxial face of apical leaves, while galls of Eurytoma sp. (Hymenoptera: Eurytomidae) predominated on the adaxial face of apical leaves. The aphids were positively affected by Crematogaster sp., relative humidity and temperature, and negatively by rainfall. Eurytoma spp. was positively affected by plant height, Crematogaster spp. and relative humidity.

RESUMO O objetivo deste trabalho foi avaliar os insetos fitófagos e os inimigos naturais presentes em mudas de pequizeiro Caryocar brasiliense Cambess.(Caryocaraceae). Detectou-se na face abaxial das folhas apicais maior número de pulgões Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) e de formigas Crematogaster sp. (Hymenoptera: Formicidae), enquanto na face adaxial desta predominaram galhas de Eurytoma sp. (Hymenoptera: Eurytomidae). Observaram-se também que os pulgões foram afetados positivamente por Crematogaster sp., umidade relativa e temperatura e negativamente por chuva. Já Eurytoma sp. possui interação positiva com altura de planta, Crematogaster sp. e umidade relativa.

Ants monopolise plant resources by shelter-construction

In Ecuadorean Amazonas, Crematogaster ants (Myrmicinae) were observed to construct shelters of debris and plant trichomes covering and hiding extrafloral nectaries of Passiflora auriculata vines. This is seen as an advanced way of excluding competing ants from a food source.

Na Amazônia Equatoriana, observou-se que formigas do gênero Crematogaster (Myrmicianae) utilizam detritos e tricomas das plantas para construir abrigos, de modo a cobrir e esconder os nectários extraflorais de Passiflora auriculata, uma planta trepadeira. Este comportamento é visto como uma maneira avançada de excluir outras formigas competidoras dos recursos alimentares (néctar) produzido pela planta.

Ants monopolise plant resources by shelter-construction

In Ecuadorean Amazonas, Crematogaster ants (Myrmicinae) were observed to construct shelters of debris and plant trichomes covering and hiding extrafloral nectaries of Passiflora auriculata vines. This is seen as an advanced way of excluding competing ants from a food source.

Na Amazônia Equatoriana, observou-se que formigas do gênero Crematogaster (Myrmicianae) utilizam detritos e tricomas das plantas para construir abrigos, de modo a cobrir e esconder os nectários extraflorais de Passiflora auriculata, uma planta trepadeira. Este comportamento é visto como uma maneira avançada de excluir outras formigas competidoras dos recursos alimentares (néctar) produzido pela planta.