A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems

Leaf-cutting ants of the genera Acromyrmex and Atta are considered the principal polyphagous pests of the Neotropics. Although some members of these genera are of economic importance, have a broad geographic distribution, and are extremely good colonizers, others are endemic and closely interact with native ecosystems. Control is generally practiced against any colony, irrespective of its taxonomic status. Indiscriminate control coupled with habitat destruction threatens endemic species with extinction, and, through habitat simplification, favors other pest species. As nests of Atta are large, having several square meters of nest surface, the endemic taxa can be easily used as environmental indicators for natural ecosystems. Likewise, the pest species can be used to detect environmental disturbance. As these ants are keystone species and easily identified by nonspecialists, efforts should be made to integrate these into viable conservation programs.

Theoretical Dynamics of Experimental Populations of Introduced and Native Blowflies (Diptera: Calliphoridae)

Equilibrium dynamics in experimental populations of Chrysomya megacephala (F.) and C. putoria (Wiedemann), which have recently invaded the Americas, and the native species Cochliomyia macellaria (F.), were investigated using nonlinear difference equations. A theoretical analysis of the mathematical model using bifurcation theory established the combination of demographic parameters responsible for producing shifts in blowfly population dynamics from stable equilibria to bounded cycles and aperiodic behavior. Mathematical modeling shows that the populations of the 2 introduced Chrysomya species will form stable oscillations with numbers fluctuating 3-4 times in successive generations. However, in the native species C. macellaria, the dynamics is characterized by damping oscillations in population size, leading to a stable population level.

The spatial dynamics of native and introduced blowflies (Dipt., Calliphoridae)

The spatial dynamics of three blowfly species was investigated using a spatially extended model of density-dependent population growth and the results indicate an overall stabilizing effect. Introduction of diffusive dispersal induced a quantitative effect of damping variation in population size on the route to a one-fixed point equilibrium in the native species, Cochliomyia macellaria. On the other hand, diffusive dispersal caused qualitative shifts in the dynamics of two invading species, Chrysomya megacephala and Chrysomya putoria. In both species diffusive dispersal can produce a qualitative shift from a two-point limit cycle to a one fixed-point dynamics. Quantitatively, dispersal also has the effect of damping oscillations in population size in the invading species.

Swarming and incipient colonies of Coptotermes havilandi (Isoptera, Rhinotermitidae)

Coptotermes havilandi Holmgren is an oriental species introduced into Brazil. Despite its economic impact as structural pest, very little is known about the biology of this termite. This paper describes observations of C. havilandi swarming in the city of Rio Claro (SP, Brazil), and reports the first data on incipient colonies reared in a laboratory in Brazil. The preoviposition period lasted about a week after pairing; oviposition began in most of the incipient colonies during the second week. Antennal mutilation occurred on all reproductives. The mean number of the first batch of eggs was 13. In general, first instar brood hatched 60-70 days after set up of the colonies. After two years of pairing there was a small population (less than 100 individuals) and limited soldier production (n=2) in incipient colonies of C. havilandi.

Ocorrência de Phoracantha recurva Newman (Coleoptera: Cerambycidae) em eucalipto no Estado de São Paulo, Brasil

This paper reports the occurrence of the longhorn beetle Phoracantha recurva Newman (Coleoptera: Cerambycidae) attacking Eucalyptus citriodora logs in the State of São Paulo, Brazil. This Australian species was introduced in the country and is considered a quarentenary pest because it may negatively influence the exporting of eucalypts logs. Details on the biology, damage and control, as well as the different morphological characteristics between P. recurva and P. semipunctata are discussed.

Little cicada of sugarcane Mahanarva posticata (Homoptera: Cercopidae). A Brazilian agricultural pest. Morpho-histological study of salivary glands

Little cicadas are homopteran insect pests of sugarcane plantations. As these insects suck out the sap from the leaf parenchyma, they inoculate a toxic saliva that damages the plant vessels, thus promoting the loss of glucose by the affected plant. The morphological and histological analyses of the salivary glands of the little cicada Mahanarva posticata, revealed that these glands are formed by 2 portions: one portion comprises a group of acini and has been denominated as the principal gland; the second portion is filamentous in nature and has been denominated as the accessory gland; it is formed by very long and fine filaments. The acinous portion of the gland can be subdivided into 2 lobes: an anterior lobe formed by 3 lobules (I, II, III), and a posterior lobe formed by lobule IV and the excretory duct. Histologically, the salivary glands showed that the filaments are empty sutructures composed by several internal channels with secretion granules being observed in the cytoplasm of the cells of the secretory filaments. Lobules I and II of the principal gland are characterized by being highly basophilic and for accumulating a large amount of secretion in both the cytoplasm of the cells and inside secretion vesicles. Histochemically, we verified that the secretion produced by these glands is lipidic and protein in nature, with the production of polysaccharides being very low. The differences in stain and appearance of the different regions of the salivary gland lead us to believe that the final glandular product is lipoproteic in nature.

Cysts reabsorption in the testis of the bee wax pest Achroia grisella (Lepidoptera, Pyralidae) during spermatogenesis

The present paper reports the occurrence of testicular cysts degeneration during spermatogenesis of Achroia grisella, a Lepidoptera with dimorphic spermatogenesis, through ultrastrucutural studies. Signs of cysts degeneration can be detected in the last larval instar but it increases during pupation and early adulthood. The degeneration affects the eupyrene, as well apyrene cysts but it is not always possible to recognize which cysts are degenerating. Some morphological features of cysts degeneration resemble apoptosis.

Management of vomplex systems: Modeling the biological pest control

The aim of this paper is to study the cropping system as complex one, applying methods from theory of dynamic systems and from the control theory to the mathematical modeling of the biological pest control. The complex system can be described by different mathematical models. Based on three models of the pest control, the various scenarios have been simulated in order to obtain the pest control strategy only through natural enemies' introduction. © 2008 World Scientific Publishing Company.

Dinâmica populacional de mosca-negra-dos-citros (Aleurocanthus woglumi Ashby, 1915) em pomares de citros em sistema agroflorestal e monocultura

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização e patogenicidade de fungos entomopatogênicos isolados do percevejo-bronzeado do eucalipto, Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dinâmica populacional de Zaprionus indianus (Gupta, 1970) (Diptera: Drosophilidae) sob condições experimentais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dinâmica populacional do psilídeo-de-concha Glycaspis brimblecombei Moore (Hemiptera: Psyllidae) e parasitismo por Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) em floresta de eucalipto

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Atividade de acaricidas sobre o Ácaro-da-leprose, Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) e sobre artrópodes benéficos na cultura dos citros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coptotermes gestroi (Isoptera, Rhinotermitidae): dinâmica de colônias inteiras, necessidades hídricas e alocação de castas entre diferentes fontes alimentares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aedes aegypti on Madeira Island (Portugal): genetic variation of a recently introduced dengue vector

The increasing population of Aedes aegypti mosquitoes on Madeira Island (Portugal) resulted in the first autochthonous dengue outbreak, which occurred in October 2012. Our study establishes the first genetic evaluation based on the mitochondrial DNA (mtDNA) genes [cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4)] and knockdown resistance ( kdr ) mutations exploring the colonisation history and the genetic diversity of this insular vector population. We included mosquito populations from Brazil and Venezuela in the analysis as putative geographic sources. The Ae. aegyptipopulation from Madeira showed extremely low mtDNA genetic variability, with a single haplotype for COI and ND4. We also detected the presence of two important kdr mutations and the quasi-fixation of one of these mutations (F1534C). These results are consistent with a unique recent founder event that occurred on the island of Ae. aegyptimosquitoes that carry kdr mutations associated with insecticide resistance. Finally, we also report the presence of the F1534C kdr mutation in the Brazil and Venezuela populations. To our knowledge, this is the first time this mutation has been found in South American Ae. aegypti mosquitoes. Given the present risk of Ae. aegypti re-invading continental Europe from Madeira and the recent dengue outbreaks on the island, this information is important to plan surveillance and control measures.