Interações entre formigas atendentes, afídeos dos cítricos e joaninhas em plantas de Citrus sinensis

Attending ants promote colony survivorship and reproduction of aphid colonies, mainly by protection against natural enemies. However, very few papers are about the assessment of the effect of attending ants directly on individuals of aphids without the presence of other organisms. In this article, a review of the main papers that had assessed the effect of the attendant ant Camponotus punctulatus (Formicidae) on the table of life of the brown-citrusaphid Toxoptera citricidus (Hemiptera: Aphididae) that grows in plants of Citrus sinensis (Rutaceae) without the presence of natural enemies. The ant behavior in the presence of adults and immature individuals of the ladybug Cycloneda sanguinea (Coleoptera: Coccinellidae) in colonies kept on Poncirus trifoliata was also evaluated. Nymph survivorship, adult total fertility, reproductive and post-reproductive period were not affected by the attending ants. The elevation of mean and daily fecundity of the aphids attending on the first days has great importance in the population growth. Ant behavior does not depend on the ladybug sex, nor on the colony size, so that ladybug larvae are more tolerated than adults in the aphid colonies. We registered that the behaviour of the aphids is similar independently of their sex and colony size, whereas ladybug larvae are more tolerated than their adults in aphid colonies.Keywords: survivorship, fecundity, table of life, population growth.As formigas atendentes aumentam a sobrevivência e a reprodução das colônias de afídeos, principalmente pela proteção contra os inimigos naturais. Entretanto, são raros os trabalhos que avaliam o efeito das formigas atendentes diretamente sobre os indivíduos sem a presença de outros organismos. Neste artigo, é feita uma revisão dos principais trabalhos que avaliaram o efeito da formiga atendente Camponotus punctulatus (Formicidae) sobre o pulgão Toxoptera citricidus (Hemiptera: Aphididae) mantido em plantas de Citrus sinensis (Rutaceae) na ausência de inimigos naturais. Também foi avaliado o comportamento dessas formigas na presença de adultos e imaturos de Cycloneda sanguinea (Coleoptera: Coccinellidae) em plantas de Poncirus trifoliata. O aumento da fecundidade média e diária de pulgões atendidos nos primeiros dias tem papel importante no crescimento populacional. Neste trabalho, observamos que o comportamento dos afídeos (T. citricidus) é semelhante independentemente do seu sexo e do tamanho das colônias de formigas (C. punctulatus), sendo que as larvas de joaninhas (C. sanguinea) são mais toleradas do que os adultos das joaninhas nas colônias de pulgões.Palavras-chave: sobrevivência, fecundidade, tabela de vida, crescimento populacional

Richness of Termites and Ants in the State of Rio Grande do Sul, Southern Brazil

Previous studies on the effects of environmental factors, such as altitude, latitude, temperature, deforestation, forest fragmentation, fire, and flood on the community structure of termites and ants were conducted in various regions of Brazil; few of them were carried out in the southernmost Brazilian state of Rio Grande do Sul. Here we describe termites and ants diversity at different sites along the four geomorphologic units of this state. We recorded 16 taxa of termites, of which three are new state records, increasing to 19 the number of termite species known to occur in the state. Accordingly, we also found 73 species and 115 morphospecies of ants, of which only one was a new record, raising to 265 taxa the number of ant species known to occur in the state. As expected, we found a higher species richness of ants than termites. The low richness of both groups relative to other Brazilian regions could be a consequence of the subtropical to temperate climate in the state, since most portions of the state are below 30o latitude, the study areas be above 500 m altitude, and other environmental characteristics of each site. We suggest a positive relationship between species richness of termites and altitude, while ant richness indicated an inverse relationship. However, our data are not conclusive, due to the low number of replications in each altitude, particularly for termites. This study is unique in presenting an updated checklist of termites and ants in the state of Rio Grande do Sul

Table S-1

Previous studies on the effects of environmental factors, such as altitude, latitude, temperature, deforestation, forest fragmentation, fire, and flood on the community structure of termites and ants were conducted in various regions of Brazil; few of them were carried out in the southernmost Brazilian state of Rio Grande do Sul. Here we describe termites and ants diversity at different sites along the four geomorphologic units of this state. We recorded 16 taxa of termites, of which three are new state records, increasing to 19 the number of termite species known to occur in the state. Accordingly, we also found 73 species and 115 morphospecies of ants, of which only one was a new record, raising to 265 taxa the number of ant species known to occur in the state. As expected, we found a higher species richness of ants than termites. The low richness of both groups relative to other Brazilian regions could be a consequence of the subtropical to temperate climate in the state, since most portions of the state are below 30o latitude, the study areas be above 500 m altitude, and other environmental characteristics of each site. We suggest a positive relationship between species richness of termites and altitude, while ant richness indicated an inverse relationship. However, our data are not conclusive, due to the low number of replications in each altitude, particularly for termites. This study is unique in presenting an updated checklist of termites and ants in the state of Rio Grande do Sul.</p

Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species.Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat

Augmenter of liver regeneration

‘Augmenter of liver regeneration’ (ALR) (also known as hepatic stimulatory substance or hepatopoietin) was originally found to promote growth of hepatocytes in the regenerating or injured liver. ALR is expressed ubiquitously in all organs, and exclusively in hepatocytes in the liver. ALR, a survival factor for hepatocytes, exhibits significant homology with ERV1 (essential for respiration and viability) protein that is essential for the survival of the yeast, Saccharomyces cerevisiae. ALR comprises 198 to 205 amino acids (approximately 22 kDa), but is post-translationally modified to three high molecular weight species (approximately 38 to 42 kDa) found in hepatocytes. ALR is present in mitochondria, cytosol, endoplasmic reticulum, and nucleus. Mitochondrial ALR may be involved in oxidative phosphorylation, but also functions as sulfhydryl oxidase and cytochrome c reductase, and causes Fe/S maturation of proteins. ALR, secreted by hepatocytes, stimulates synthesis of TNF-α, IL-6, and nitric oxide in Kupffer cells via a G-protein coupled receptor. While the 22 kDa rat recombinant ALR does not stimulate DNA synthesis in hepatocytes, the short form (15 kDa) of human recombinant ALR was reported to be equipotent as or even stronger than TGF-α or HGF as a mitogen for hepatocytes. Altered serum ALR levels in certain pathological conditions suggest that it may be a diagnostic marker for liver injury/disease. Although ALR appears to have multiple functions, the knowledge of its role in various organs, including the liver, is extremely inadequate, and it is not known whether different ALR species have distinct functions. Future research should provide better understanding of the expression and functions of this enigmatic molecule

Social structure and growth rate of the colonies of Linepithema humile Mayr (Hymenoptera: Formicidae)

O presente trabalho teve por objetivos avaliar o comportamento agonístico entre operárias de ninhos distintos de Linepithema humile Mayr, determinar o período de produção de sexuados e a proporção sexual, estimar a variação do tamanho da população intranidal no verão e no inverno, e investigar a biologia reprodutiva, em especial, a taxa de crescimento de pequenas colônias. Para tal, coletaram-se em campo 26 ninhos de L. humile no município de Limeira, SP, transferidos para laboratório e mantidos em condições experimentais. Avaliaram-se os níveis de agressividade em pares de operárias de ninhos distintos (n = 11) em três tempos ao longo de um ano após as coletas. Avaliou-se a população intranidal através da contagem de todos os indivíduos de dez ninhos (cinco por estação). Estimou-se a taxa de crescimento para diferentes tamanhos de propágulos (10, 50, 100, 150, 200 e 500 operárias). A população de Limeira apresentou estrutura social unicolonial, com ausência de agressividade entre operárias de ninhos distintos. As operárias de L. humile foram altamente agressivas em relação a operárias de uma população proveniente do município de São Paulo. A produção de sexuados ocorreu durante o verão, com investimento sexual a favor das fêmeas (2,4 : 1). No inverno, encontrou-se um número de operárias cerca da metade do registrado no verão. O tamanho inicial dos propágulos influenciou positivamente a produção de prole total e, negativamente, a produção de prole |per capita. A taxa de crescimento per capita não variou entre os tamanhos de propágulos iniciais testados. A redução do número de operárias poderia ser decorrente de condições abióticas durante o inverno, especialmente da baixa umidade e precipitação. Algumas hipóteses são levantadas para explicar a proporção sexual a favor das fêmeas encontrada. Finalmente, destaca-se que este é o primeiro registro da existência da estrutura social unicolonial em uma população de L. humile no Brasil.The aim of this work was to evaluate the aggressive behavior between workers from different nests of Linepithema humile Mayr, to determine the period of sexual production and the sexual ratio, to estimate the variation in the intranest population between summer and winter, and to investigate the reproductive biology, particularly the role of propagule sizes in the growth rates. For such, 26 nests collected in the Limeira population of the Argentine ant were set up in experimental nests in laboratory. The levels of aggressive behavior between workers from different nests (n = 11) were evaluated for three different periods during one year after nests collections. The intranest population was assessed by direct counting of total individuals in ten nests (five for each season). The growth rate was evaluated for different propagule sizes (10,50, 100, 150, 200 and 500 workers). The Limeira population structured as unicolonial, with absence of aggressive behavior to non nestmates workers. Workers from the Limeira population were highly aggressive to workers from another population (São Paulo). The population was strongly female-biased (2,4 : 1), with sexuals being produced during summer time. Worker number had a two fold reduction during winter compared to summer nests. The initial propagule size positively influenced the total brood production and negatively affected the per capita brood production. Per capita growth rates remained the same for all initial propagule sizes tested. Worker density reduction could be related to abiotic conditions during winter, especially relative humidity and rain falI. Several hypotheses are raised to explain the female-biased sexual ratio found in the studied population. This is the first record of unicoloniality in a Brazilian population of the Argentine ant