The predatory mite Stratiolaelaps scimitus as a control agent of the fungus gnat Bradysia matogrossensis in commercial production of the mushroom Agaricus bisporus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of Prey Size on the Predatory Behavior of Ectatomma brunneum (Hymenoptera: Formicidae) Under Laboratory Conditions

The influence of prey size on the predatory behavior and behavioral sequence of Ectatomma brunneum under laboratory conditions was evaluated. Two behaviors were characterized: rejection and attack, the latter divided into individual and group attack. In the group attack, prey transport (Tenebrio molitor larvae) into the nest prevailed, whether immobilized as a consequence of the ant venom or not. on the other hand, in the individual attacks such behavior was not observed. There was no significant relation between the predatory behavior and the size of the larvae offered, indicating that prey dimensions do not interfere with predation. The high rejection rates registered in the experimental trials may have been a consequence of the absence of immatures in the nests used in the research and/or the decrease in the activities observed, considering that the experiments were carried out in the coldest time of the year.

Evaluating the use of predatory insects as bioindicators of metals contamination due to sugarcane cultivation in neotropical streams

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

THAUMATOMYRMEX STRIPS MILLIPEDES FOR PREY - A NOVEL PREDATORY BEHAVIOR IN ANTS, AND THE 1ST CASE OF SYMPATRY IN THE GENUS (HYMENOPTERA, FORMICIDAE)

We describe, for the first time, the predatory behaviour of Thaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations of T. atrox and a field and laboratory study of T. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend in Thaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and other Thaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests that Thaumatomyrmex includes several species. and not only one highly variable taxon, as hypothesized earlier.

Effect of air humidity on the egg viability of predatory mites (Acari: Phytoseiidae, Stigmaeidae) common on rubber trees in Brazil

Rubber pest mites, Calacarus heveae and Tenuipalpus heveae, reach economic damage levels at the end of the rainy season and the beginning of the dry season in Brazil. Therefore, low humidity adaptation might be an important characteristic for predatory mites to successfully control pest organisms. This study determined the effect of the relative humidity (RH) levels of 30-100% on the hatching of larvae of Amblyseius acalyphus, Euseius citrifolius, Iphiseiodes zuluagai, Metaseiulus camelliae, Agistemus floridanus and Zetzellia malvinae at 25 ± 0.5°C. These predatory mites are common on rubber trees in the state of São Paulo and might be used for introduction in the major rubber tree production regions in the state of Mato Grosso. At 70% RH or higher, viability was 70% or higher for all species, indicating that their performance might be higher during the rainy season than during the dry season. Eggs of E. citrifolius and M. camelliae presented higher viability at the lower relative humidity levels than those of other species, indicating that these species might have higher chance to persist in the dry season. It is suggested that M. camelliae should be further evaluated for introduction in the state of Mato Grosso, considering that this mite is not yet present in that area. © Springer 2006.

Predatory behavior of Canthon virens (Coleoptera: Scarabaeidae): A predator of leafcutter ants

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 while flying in a zigzag pattern, 15 to 20cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior of Canthon virens, a predator poorly studied in Brazil and widespread in the country. Copyright © 2012 Luiz Carlos Forti et al.

Effects of neem oil (Azadirachta indica A. Juss) on midgut cells of predatory larvae Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae)

The effects of ingested neem oil, a botanical insecticide obtained from the seeds of the neem tree, Azadirachta indica, on the midgut cells of predatory larvae Ceraeochrysa claveri were analyzed. C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% during throughout the larval period. Light and electron microscopy showed severe damages in columnar cells, which had many cytoplasmic protrusions, clustering and ruptured of the microvilli, swollen cells, ruptured cells, dilatation and vesiculation of rough endoplasmic reticulum, development of smooth endoplasmic reticulum, enlargement of extracellular spaces of the basal labyrinth, intercellular spaces and necrosis. The indirect ingestion of neem oil with prey can result in severe alterations showing direct cytotoxic effects of neem oil on midgut cells of C. claveri larvae. Therefore, the safety of neem oil to non-target species as larvae of C. claveri was refuted, thus the notion that plants derived are safer to non-target species must be questioned in future ecotoxicological studies. © 2012 Elsevier Ltd.

Effect of Egg Rearing Temperature and Storage Time on the Biological Characteristics of the Predatory Stink Bug Podisus nigrispinus (Hemiptera: Pentatomidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interactions of Bacillus thuringiensis bioinsecticides and the predatory stink bug Podisus nigrispinus to control Plutella xylostella

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Karyotype diversity among predatory Reduviidae (Heteroptera)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Homology in a context dependent predatory behavior in spiders (Araneae)

Stereotyped behaviors have been routinely used as characters for phylogeny inference, but the same cannot be said of the plastic aspects of performance, which routinely are taken as a result of ecological processes. In this paper we examine the evolution of one of these plastic behavioral phenotypes, thus fostering a bridge between ecological and evolutionary processes. Foraging behavior in spiders is context dependent in many aspects, since it varies with prey type and size, spider nutritional and developmental state, previous experience and, in webweavers, is dependent on the structure of the web. Reeling is a predatory tactic typical of cobweb weavers (Theridiidae), in which the spider moves the prey toward her by pulling the capture thread (gumfoot) to which it is adhered. Predatory reeling is dependent on the gumfoot for its expression, and has not been previously reported in orbweavers. In order to investigate the evolution of this web dependent behavior, we built artificial, pseudogumfoot lines in orbwebs and registered parameters of the predatory tactics in this modified web. Aspects of the predatory tactics of 240 individuals (12 species in 4 families) were measured, and the resulting data were optimized on the phylogeny of Orbiculariae. All species perform predatory reeling with the pseudogumfoot lines. Thus, predatory reeling is homologous for the whole Orbiculariae group. In nature, holes made by insects in ecribellate orbs produce pseudogumfoot lines (similar to out experimentally modified webs), and thus reeling occurred naturally in ecribellates. Nevertheless, outside lab conditions, predatory reeling does not occur among cribellate orbweavers, so that this behavior could not have been selected for in the cribellate ancester of orbweavers. Cribellate spiders are flexible enough as to present novel and adaptive predatory responses (reeling) even when exposed for the first time to conditions outside their usual environment. Thus, the evolution of reeling suggests and alternative mechanism for the production of evolutionary novelties; that is, the exploration of unusual ecological conditions and of the regular effects these abnormal conditions have on phenotype expression.

Susceptibility to deltamethrin in the predatory mites Neoseiulus californicus and Phytoseiulus macropilis (Acari: Phytoseiidae) populations in protected ornamental crops in Brazil

Knowledge of inter and intra-specific variation in the susceptibility of natural enemies to pesticides could help to better design integrated pest management strategies. The objective of this research was to evaluate the susceptibility to deltamethrin in populations of the predatory mites Neoseiulus californicus (McGregor) and Phytoseiulus macropilis (Banks) populations collected from protected ornamental crops in Brazil. The susceptibility to deltamethrin was characterized against immature and adult stages of both species. The impact of this insecticide was also measured by estimating the intrinsic rate of increase (r (i)). The immature and adult stages of N. californicus were approximately 3,600 and 3,000-fold more tolerant to deltamethrin than those of P. macropilis. However, high variability in the susceptibility to this insecticide was detected among P. macropilis populations, with resistance ratios of up to 3,500-fold. The selection of deltamethrin-resistant strains of P. macropilis could be exploited in applied biological control programs.

Prey digestion in the midgut of the predatory bug Podisus nigrispinus (Hemiptera: Pentatomidae)

Pre-oral digestion is described as the liquefaction of the solid tissues of the prey by secretions of the predator. It is uncertain if pre-oral digestion means pre-oral dispersion of food or true digestion in the sense of the stepwise bond breaking of food polymers to release monomers to be absorbed. Collagenase is the only salivary proteinase, which activity is significant (10%) in relation to Podisus nigrispinus midgut activities. This suggests that pre-oral digestion in P. nigrispinus consists in prey tissue dispersion. This was confirmed by the finding of prey muscles fibers inside P. nigrispinus midguts. Soluble midgut hydrolases from P. nigrispinus were partially purified by ion-exchange chromatography, followed by gel filtration. Two cathepsin L-like proteinases (CAL1 and CAL2) were isolated with the properties: CAL1 (14.7 kDa, pH optimum (pHo) 5.5, km with carbobenzoxy-Phe-Arg-methylcoumarin, Z-FR-MCA, 32 mu M); CAL2 (17 kDa, pHo 5.5, km 11 mu M Z-FR-MCA). Only a single molecular species was found for the other enzymes with the following properties are: amylase (43 kDa, pHo 5.5, km 0.1% starch), aminopeptidase (125 kDa, pHo 5.5, km 0.11 mM L-Leucine-p-nitroanilide), alpha-glucosidase (90 kDa, pHo 5.0, km 5 mM with p-nitrophenyl alpha-D-glucoside). CAL molecular masses are probably underestimated due to interaction with the column. Taking into account the distribution of hydrolases along P. nigrispinus midguts, carbohydrate digestion takes place mainly at the anterior midgut, whereas protein digestion occurs mostly in middle and posterior midgut, as previously described in seed- sucker and blood-feeder hemipterans. (C) 2012 Elsevier Ltd. All rights reserved.

Morphological, molecular and cross-breeding analysis of geographic populations of coconut-mite associated predatory mites identified as Neoseiulus baraki: evidence for cryptic species?

Surveys were conducted in Brazil, Benin and Tanzania to collect predatory mites as candidates for control of the coconut mite Aceria guerreronis Keifer, a serious pest of coconut fruits. At all locations surveyed, one of the most dominant predators on infested coconut fruits was identified as Neoseiulus baraki Athias-Henriot, based on morphological similarity with regard to taxonomically relevant characters. However, scrutiny of our own and published descriptions suggests that consistent morphological differences may exist between the Benin population and those from the other geographic origins. In this study, we combined three methods to assess whether these populations belong to one species or a few distinct, yet closely related species. First, multivariate analysis of 32 morphological characters showed that the Benin population differed from the other three populations. Second, DNA sequence analysis based on the mitochondrial cytochrome oxidase subunit I (COI) showed the same difference between these populations. Third, cross-breeding between populations was unsuccessful in all combinations. These data provide evidence for the existence of cryptic species. Subsequent morphological research showed that the Benin population can be distinguished from the others by a new character (not included in the multivariate analysis), viz. the number of teeth on the fixed digit of the female chelicera.