Luiz Carlos Forti

Leaf-cutting ants are economically important pest insects in the Neotropical region. They forage on fresh leaves and flowers that serve as substrates for the cultivation of their mutualistic fungus, which they feed upon. The main active ingredient for their control is sulfluramid, but the restriction of its use is under discussion. In this study, t...

Leaf-cutter ants are considered agricultural pests in the Neotropical region, and great is the demand for a biological control of their populations. The present study isolated entomopathogenic fungi of winged reproductive females (queens) of the genus Attaand assessed their in vitrocharacteristics, in order to provide resources for future studies i...

Colonies of leaf-cutting ants of the genus Atta need to collect large quantities of vegetal substrate in their environment to ensure their growth. They do so by building and extending over time a foraging network that consists of several underground tunnels extending above ground by physical trails. This paper presents a longitudinal study of the f...

The symbiosis between fungi and leaf-cutting ants (Hymenoptera: Formicidae) has aroused the interest of researchers about the mechanism used by ants to select plants. The nutritional needs of the fungus garden, and the absence of potentially deleterious substances from plants, are criteria for selection by foraging workers. This is supported by beh...

Leaf-cutter ants perform a series of specialized behaviors in preparing plant substrates for their symbiotic fungus. This process may be related to contamination of workers by substances such as insecticides, leading us to hypothesize that substances are spread among workers through behaviors they perform to grow the fungus. To test this hypothesis...

Toxic baits are the most efficient method to control leaf-cutter ants in eucalyptus forests for paper and cellulose production. For the proper use of these baits, insecticide compounds must reach workers and contaminate them. Thus, understanding how these baits are processed inside the nests is vital for a successful control, especially when it com...

Leaf-cutting ants are insects that use plant material to grow fungus from which they feed. These fungus-growing ants perform various behavioral activities to establish an environment conducive to the fungus. Among these behaviors are activities that can serve to detect materials harmful to the colony, such as licking, scraping, chopping, etc. Howev...

Atta bisphaerica is a species of grass-cutting ants commonly found in the Cerrado biome. The Brazilian Cerrado (savanna) biome covers 2. million. km representing 23% of the area of the country. It is an ancient biome with rich biodiversity, estimated at 160,000 species of plants, fungi and animals. However, little is known about their nest architec...

Studies related to the demography of individual members from ant colonies have received little attention, although they are the basis to understanding the population dynamics of colonies. Thus, the objective of this work was to study the queen oviposition rate and the duration of the life cycle and longevity of Acromyrmex rugosus rugosus workers. T...

The leaf-cutting ant present a polymorphism accentuated with a coordinate division of labor among castes of workers. However, there are controversies regarding the number of castes in Acromyrmex species. In this way, the objective of this work was to determine the number of size classes of Acromyrmex rugosus rugosus workers and the morphometric var...

Novelty Statement — We tested the hypothesis of Holmes and Sherman (1983) that an individual that emerges in a mixed colony integrates the chemical signals of the social environment We concluded that A. subterraneus molestans and A. subterraneus brunneus workers tend to prefer larvae of their own species, regardless of whether or not they are conco...

Dianfenthiuron is a pre-insecticide that can be activated by photolysis, and may 25 be a promising formicide. This study evaluated the effect of diafenthiuron after photolysis in 26 colonies of Atta sexdens rubropilosa Forel, 1908. The experiment was conducted in a completely 27 randomized design with five treatments and five replications: control...

This study investigated the stimuli that trigger digging behavior in Acromyrmex subterraneus during nest building. The hypothesis was that the presence of the fungus garden and/or brood triggers the excavation of tunnels and chambers. For the experiment, the excavation rate of individually marked workers kept in plastic cylinders filled with soil w...

Social animals are faced with an intriguing dilemma. On the one hand, interactions between individuals are essential to exchange information and to promote cohesion, while on the other hand such interactions carry with them the risk of catching and transmitting parasites. This trade-off is particularly significant for social insects because low wit...

Feed adaptation is crucial for the ecological success of animals, which explore specific or varied resources according to the suitability of the selected feature. We hypothesized that the mandibles of leaf-cutting ants exhibit a greater degree of specialization because of the specific food preference of some species. The objective of this study was...

The relationship of attine ants with their mutualistic fungus and other microorganisms has been studied during the last two centuries. However, previous studies about the diversity of fungi in the ants’ microenvironment are based mostly on culture-dependent approaches, lacking a broad characterization of the fungal ant-associated community. Here, w...

The nest dug by the leaf-cutter ant queen of the genus Atta is a vertical tunnel interconnected to a small chamber to hold its offspring and the symbiotic fungus. The depth of the initial chamber of the Atta sexdens rubropilosa ranges from 10 to 30 cm below the soil surface. This available information, could it be that the ideal initial nest depth...

A great number of plant species is collected selectively in the habitat by leaf-cutting ants, but it is unknown about anatomy of leaves and silicon content of preferred plants. Thus, our study was investigated the leaf anatomy and silicon content in the foraged plants by grass-cutting and leaf-cutting ants Atta bisphaerica and Atta sexdens rubropil...

Fungus gardens of leaf-cutting ants harbor diverse alien fungi in addition to their fungal cultivar. Previous work suggested that alien microorganisms are likely derived from the substrata foraged by ant workers and incorporated into the fungus gardens. To test this hypothesis, we sampled 1014 garden fragments from 16 field colonies of Atta sexdens...

Several biological, chemical, cultural and mechanical methods have been studied for the control of leaf-cutting ants due to their economic importance in forestry, agriculture and pastures. Applied biological methods such as manipulating predators, parasitoids and microorganisms; conservative control, non-preferred plants (resistents), extracts of t...

Several biological, chemical, cultural and mechanical methods have been studied for the control of leaf-cutting ants due to their economic importance in forestry, agriculture and pastures. Applied biological methods such as manipulating predators, parasitoids and microorganisms; conservative control, non-preferred plants (resistents), extracts of t...

Acromyrmex balzani is a grass-cutting ant species frequently found in Cerrado areas. However, little is known about the architecture of the polydomous nests of this ant. Fifteen A. balzani nests located in a cerrado region in Botucatu, São Paulo, Brazil, were studied. The polydomous nests were studied in three ways. First, we investigated the archi...

The objective of this study was to investigate the seasonal change in the pattern of foraging activity in the leaf-cutting ant Atta capiguara and to provide an estimate of the annual herbivory rate of its colonies. We surveyed at least once a month during 12 months, the foraging activity of two colonies located in a pasture of central Brazil. Each...

Foraging networks are a key element for ant colonies because they facilitate the flow of resources from the environment to the nest and they allow the sharing of information among individuals. Here we report the results of an 8-month survey, extending from November 2009 to June 2010, of the foraging networks of four mature colonies of Atta bisphaer...

General view of the field site. (TIF)

Map of the foraging trails of Nest 3 on the last day of visit. Each color corresponds to the survey date at which the foraging holes and trails were first observed. (TIF)

Map of the foraging trails of Nest 2 on the last day of visit. Each color corresponds to the survey date at which the foraging holes and trails were first observed. (TIF)

Assessment of the effort put in physical trail construction over the 8-month survey. Cumulated length of new physical foraging trails. The bold continuous line shows the predictions of a Generalized Additive Mixed Model with nest as random variable; the dashed lines show the predictions ± CI0.95. (TIFF)

Map of the foraging trails of Nest 1 on the last day of visit. Each color corresponds to the survey date at which the foraging holes and trails were first observed. (TIF)

Map of the foraging trails of Nest 4 on the last day of visit. Each color corresponds to the survey date at which the foraging holes and trails were first observed. (TIF)

Direction of the mean vectors of the end point of foraging trails at each visit. The angles are measured anticlockwise, with 0° corresponding to the East. Big and small stars indicate the visits for which the direction of the end points of the foraging trails were significantly concentrated (at P<0.01 and 0.05>P>0.01, respectively) around the direc...

This study aimed to evaluate the occurrence of natural parasitism in Acromyrmex landolti Forel, to identify parasitoids associated to the species and to estimate parasitism rates. The experiment was conducted from January to May 2012 in Itapetinga, BA. A sample comprised of 20 nests was studied. Nests were excavated, eggs, larvae, pupae and adults...

Leaf-cutting ants rely on the obligate symbiosis with a fungus, Leucoagaricus gongylophorus, on which they feed. This fungus garden is maintained preferentially with green leaves in combination with other tissues of plant origin. The nutritional composition of this symbiotic relationship is extremely beneficial for the colony, representing the main...

Dynamics of the restoration of physical trails in the grass-cutting ant Atta capiguara. Leaf-cutting ants of the genus Atta build long physical trails by cutting the vegetation growing on the soil surface and removing the small objects they find across their path. Little is known on the dynamics of trail construction in these ants. How much time do...

The nuptial flight and nest digging are high intensity activities which consume body reserves. The flight and digging effort was quantified by measuring the carbohydrate and total lipids content in males and females before and after the nuptial flight, and the queen's digging effort during the foundation. The digging effort was quantified by experi...

Foraging behavior of leaf cutting ants: How do workers search for their food? Forager ants search for adequate food sources in nature and, after their discovery, they decide whether the source is suitable or not for the colony. However, we asked "How do workers seek out the substrate for cultivation of the symbiontic fungus on which they feed? To a...

Seeds of different plant species constitute an alternative but also significant substrate that leaf-cutting ants use to cultivate their fungus garden. However, how they are processed inside the nest and if their use implies differential allocation of worker size classes are still poorly known. Using laboratory colonies of Acromyrmex subterraneus (F...

Before the mating flight, the gyne of leaf-cutting ants takes a small pellet of their mutualistic fungus garden to start fungus culture in its new colony by vertically transmitting it. This mutualism is threatened by the specialized microfungal parasite Escovopsis, which is exclusively associated with the ant’s fungus gardens. Evidences suggest tha...

Morphological differences among mandibles of grass and leaf-cutting ant species were examined. Specifically, we compared morphometric measurements from mandibles of four species (Atta laevigata, A. bisphaerica, Acromyrmex balzani, and Ac. subterraneus). It was found that these Atta species had similar mandible morphologies, primarily differing in d...

Atta laevigata and Atta capiguara are two species of leaf-cutting ants that are found in the pastures of Central Brazil and build huge underground nests linked to the outdoor environment by underground tunnels, which can reach several tens of meters and further extend through foraging trails to distant foraging grounds. The tunnels built by mature...

Leaf-cutting ants modify the properties of the soil adjacent to their nests. Here, we examined whether such an ant-altered environment impacts the belowground fungal communities. Fungal diversity and community structure of soil from the fungus garden chambers of Atta sexdens rubropilosa and Atta bisphaerica, two widespread leaf-cutting ants in Braz...

Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase. This study evaluated the crude protein content of queens of Atta sexdens before the nuptial flight and after the claustral phase in laboratory and field colonies. The hypothesis was that protein is used for survival of the queen and for early c...

Most ants, as leaf cutting ants, construct nests underground to maintain environmentalconditions favorable to the development of immature and adult individuals. But there was little works about this, especially doing comparison of nest growth among leafcutting ant species. Thus, we studied the growth of nests of the leaf-cutting ants Atta bisphaeri...

Fungus-growing ants of the genus Atta are known for their leaf-cutting habit, a lifestyle they have maintained since their 50-million-year-old co-evolution with a mutualistic fungus, cultivated as food. Recent studies have highlighted that, in addition to the mutualistic fungus, nests of ants harbor a great diversity of microbial communities. Such...

O objetivo foi estudar a seletividade de inseticidas aos inimigos naturais na cultura do algodão (Gossypium hirsutum L.r. latifolium Hurtch), cultivar DeltaOpal, no município de Malhada (BA) e conhecer a fauna benéfica associada. O trabalho foi conduzido na safra 2010/2011, com delineamento experimental em blocos ao acaso, com seis tratamentos e qu...

There are several types of potential hazards associated with the use of pesticides, among them, soil contamination during their underground application. The trade-off between control effectiveness and soil contamination can be observed during the control of leaf-cutting ants using thermal fogs in South American agricultural and forest plantations....

Energetic cost of digging behavior in workers of the leaf-cutting ant Atta sexdens (Fabricius). During nest excavation, leaf-cutting ant workers undergo reduction in their body reserve, particularly carbohydrates. In order to estimate the energetic cost of digging, groups of 30 workers of the leaf-cutting ant Atta sexdens were sealed in a hermetic...

Energy substrate used by workers of leaf-cutting ants during nest excavation. In this study we aimed to ascertain whether leaf-cutting ant workers lose body reserves (fat or sugars) as a function of nest excavation. For each treatment, we isolated 10 workers of Atta sexdens into two experimental groups, Control (C- without excavation) and Soil (S-...

O conhecimento do conteúdo energético das operárias é essencial para mensurar a disponibilidade energética, responsável pela manutenção e execução de atividades essenciais para o crescimento da colônia de formigas. Mas pouco se conhece sobre o conteúdo energético das operárias e quanto estará disponível para realizar atividades de, por exemplo, esc...

The knowledge of the workers energy content is essential to measure the energy availability for maintenance and performance of activities essences for the colony growth. But little is known about the workers energy content, and how much will be available to carry out activities, for example, the excavation of the nest. The present study determined...

Será que a vida em grupo acarreta uma maior atividade individual, e consequentemente, um maior gasto energético? Para responder a essa questão, hipotetizou-se que exista uma maior produção de CO2, quando se aumenta o tamanho do grupo de formigas operárias e, consequentemente, um maior custo energético ao indivíduo quando está em grupo. Assim, grupo...

Nest digging spends a lot of energy existing a question about how much energy is required to dig the tunnel and initial chamber. It was hypothesized that the lipid content is used during nest digging. This hypothesis was tested by comparing the consequences of increasing digging effort in queens that were experimentally stimulated to excavate a com...

Annually, mature colonies of Atta ants produce winged males and females, where leave the colony in which they were produced to form new colonies and thus continue the species perpetuation. The foundation of Atta spp. colonies always involves high queen effort, solely responsible for growing the fungus and the care with itself and its offspring. Dur...

Since 2009, when sulfluramid was listed in annex B of the Stockholm Convention's Persistent Organic Pollutants, effort has been made to search for other active ingredients to use in baits for controlling leaf-cutting ants in Brazil. Considering that active ingredients that inhibit insect cellular respiration have been shown to be effective in contr...

Ants of the genera Atta and Acromyrmex (Myrmicinae: Attini) are in general pests for agricultural and pasture areas. In southwestern Bahia pastures, in Brazil, Acromyrmex landolti Forel occurs at intermediate densities of 260 nests ha-1. In spite of its economic importance, there is not enough research on the bioecological aspects of such species....

Adult nests of leaf cutting ants (genus Atta and Acromyrmex) are composed of thousands of underground chambers, which harbor the fungus garden, garbage and their population. However, how the chambers are constructed? To answer this question, we hypothesized that the fungus garden acts as a template for the chambers construction. Thus, we used 20 co...

Nest ventilation should be particularly relevant for the huge colonies of leaf-cutting ants, genus Atta. Considerable amounts of O2 are consumed and CO2 produced by both the fungus gardens and the ants inside nest chambers, which are located at deep soil layers characterized by high CO2 and low O2 concentrations. In this work, passive nest ventilat...

We present a detailed description of the predatory behavior of the beetle Canthon virens Mannerheim, 1829, on the leafcutter ant Atta sp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis. Canthon virens exhibited 28 behaviors while predating upon Atta sp. queens. Adult beetles search for queens...

The nuptial flight allows males and females to meet and copulate and both need energy to perform this activity. Before leaving the nest, males and females are well nourished and ready to mate. However, little is known about the lipid and energy contents in females before the nuptial flight (virgins) and after it (mated females). In this work we mea...

The diet of leaf-cutting ants is based on cultivation of their symbiotic fun-gus, whose successful cultivation depends on the task of incorporation and handling of vegetable substrate. This task may cause the workers to be con-taminated with toxic substances and thus decrease the survival of the colony. The objective of this study was to analyze th...

The present study aimed to evaluate the carrying and effect of (dry) granulated baits containing conidia of entomopathogenic fungi among colonies of the leaf-cutting ant Atta sexdens rubropilosa in the laboratory. This bait type was chosen to facilitate its eventual commercial use. Two applications were performed: in the first, baits with 1x108 con...

Leaf-cutting ant workers dig underground chambers, for housing their symbiotic fungus, interconnected by a vast quantity of tunnels whose function is to permit the entrance of food (leaves), gaseous exchanges, and movement of workers, offspring, and the queen. Digging is a task executed by a group of workers, but little is known about the group eff...

Export Date: 6 May 2014, Source: Scopus, Art. No.: 921465

Trabalhos referentes à produção de macrofotografias de insetos são pouco difundidos no meio científico-acadêmico. No entanto, o uso de imagens apresenta vasta aplicação, servindo para publicações científicas, conferências, cursos, banco de dados e na elaboração de chaves de identificação ilustradas. Sendo assim, foram desenvolvidas metodologias que...

Trabalhos referentes à produção de macrofotografias de insetos são pouco difundidos no meio científico-acadêmico. No entanto, o uso de imagens apresenta vasta aplicação, servindo para publicações científicas, conferências, cursos, banco de dados e na elaboração de chaves de identificação ilustradas. Sendo assim, foram desenvolvidas metodologias que...

A correta identificação de um inseto de interesse econômico é premissa básica para a solução de qualquer problema entomológico. Ela facilita a busca e a obtenção de toda a informação bibliográfica previamente existente sobre o tema. Entretanto, a identificação é uma atividade difícil, que demanda tempo considerável, tornando-se muitas vezes desesti...

Leaves of copperleaf (Acalypha spp.) are greatly accepted by leaf-cutting ants and therefore used to maintain colonies in the laboratory. In order to determine the attractive potential of granulated bait of Acalypha wilkesiana leaves versus citrus pulp, currently used in commercial baits, an evaluation was performed, by using the leaf-cutting ant A...

To better understand the potential of controlling of leaf-cutting ants, a serious pest, with conventional synthetic insecticides as well as botanical pesticides, we propose to evaluate the effect of d-limonene on attractiveness and rejection of citric pulp to the leaf-cutting ant Atta sexdens rubropilosa Forel. Five treatments were adopted that con...

The preference of Atta capiguara Gonçalves for young leaves was evaluated and developed for nine grass species. Hyparrhenia rufa, Paspalum notatum cv Comum and Andopogon gayanus were the most preferred. Paspalum notatum cv Pensacola, Brachiaria decumbens and Cynodon dactylon cv Coast Cross presented intermediate preference. Brachiaria brizantha, Br...

Leaf-cutting ants (Hymenoptera, Formicidae)