RESUMO
In this review article, we present and discuss the main factors influencing the change in pest status of phytophagous stink bugs (Hemiptera: Heteroptera: Pentatomidae) in the Neotropics. We have surveyed the published records over the past 50 years and divided this timeframe into decades. This was done to rank in time the relative abundance (percentage) of the following species, known pests of commodities, in the Neotropical Region: the Neotropical brown stink bug, Euschistus heros (F.); the green-bellied stink bugs, Diceraeus melacanthus Dallas and D. furcatus (F.); the redbanded stink bug, Piezodorus guildinii (Westwood); the southern green stink bug, Nezara viridula (L.); and the brown-winged stink bug, Edessa meditabunda (F.). The analysis showed that E. heros, D. melacanthus, and D. furcatus, formerly minor pests, in the last decade (2010s) became major pests. The once most important pest species, N. viridula and P. guildinii, decreased their pest status in the last decade. Edessa meditabunda, which never achieved high populations, showed a tendency to increase in abundance in the last two decades (2000s and 2010s). Major factors believed to influence the dynamics of pest populations of stink bugs in the Neotropics include cropping systems (no-tillage replacing conventional soil plowing, and crop rotation); genetically modified (GM) plants (mostly plants expressing insecticidal crystalline proteins derived from Bacillus thuringiensis Berliner - Bt); change in availability of host and associated plants in the new landscape scenario; increased usage of chemicals (insecticides, fungicides, and herbicides); and change in the role of natural enemies in modern day agriculture.
Assuntos
Glycine max , Heterópteros , AnimaisRESUMO
This study identified chemicals found on the eggs of two stink bug species, one native to western North America, Euschistus conspersus, and an invasive species from Asia, Halyomorpha halys. The responses of two scelionid egg parasitoids, Trissolcus erugatus and Telenomus podisi, toward natural stink bug egg volatiles, and synthetic reconstructions of egg volatiles, were tested in bioassays. A compound, methyl (2E,4Z)-2,4-decadienoate, previously identified as the major component of the male-produced aggregation pheromone of E. conspersus, was the major volatile identified from extracts of E. conspersus eggs. In contrast, for H. halys, the sesquiterpenoids that compose the male-produced aggregation pheromone of this species were not detected on eggs, whereas the presence of hexadecanal, octadecanal, and eicosanal was detected. In laboratory olfactometer tests, both Tr. erugatus and Te. podisi females were attracted to extracts of E. conspersus eggs, and to synthetic methyl (2E,4Z)-2,4-decadienoate. However, female Tr. erugatus and Te. podisi wasps were repelled, both by extracts of H. halys eggs and by a blend of the aldehydes identified from H. halys eggs. A follow-up field study, using hexane-washed and intact E. conspersus as sentinel eggs, showed that the parasitoids Trissolcus erugatus and Gryon obesum emerged from these eggs. Sentinel hexane-washed eggs treated with 3 ng of methyl (2E,4Z)-2,4-decadienoate were parasitized more by these two species than were hexane-washed or unwashed eggs, whereas hexane-washed eggs treated with a comparable dose of the C16,18,20 aldehyde mixture were avoided by these parasitoids. In a further field experiment, Trissolcus basalis was the primary parasitoid found in sticky traps baited with methyl (2E,4Z)-2,4-decadienoate, indicating that this species was attracted to, but either did not oviposit or develop in the E. conspersus sentinel eggs in the previous experiment.
Assuntos
Heterópteros/parasitologia , Óvulo/parasitologia , Vespas/fisiologia , Animais , Decanoatos/análise , Decanoatos/metabolismo , Feminino , Heterópteros/química , Heterópteros/fisiologia , Interações Hospedeiro-Parasita , Masculino , Oviposição , Óvulo/química , Óvulo/fisiologia , Controle de Pragas , Feromônios/análise , Feromônios/metabolismo , Olfato , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/metabolismo , Vespas/anatomia & histologiaRESUMO
This work describes the structural elucidation of the sex pheromone of the soybean stink bug, Pallantia macunaima. The biological activity of the synthetic pheromone was demonstrated by behavioral and EAD experiments. Furthermore, the absolute configuration of the natural pheromone was determined as (6R,10S)-6,10,13-trimethyltetradecan-2-one. This is the first ketone identified as a male-produced sex pheromone in Pentatomidae, and the trivial name, pallantione, was assigned to this novel pheromone molecule.
Assuntos
Decanoatos/isolamento & purificação , Hemípteros/química , Atrativos Sexuais/isolamento & purificação , Animais , Decanoatos/química , Decanoatos/metabolismo , Hemípteros/fisiologia , Masculino , Estrutura Molecular , Feromônios/química , Atrativos Sexuais/química , Atrativos Sexuais/metabolismo , EstereoisomerismoRESUMO
Phthia picta is part of a complex of true bugs (Heteroptera) in Brazil that attack tomatoes, being particularly damaging because nymphs and adults feed on both leaves and fruit. Gas chromatography (GC) of aeration extracts of adult males vs. females revealed the presence of a male-specific compound. GC-electroantennographic detector experiments indicated that the antennae of females are highly sensitive to this male-specific compound. GC-mass spectrometry and GC-FTIR analyses suggested a methyl branched hydrocarbon structure for this compound. After synthesis of three different proposed structures, the natural product was indentified as 5,9,17-trimethylhenicosane, which was strongly attractive to females in Y-tube olfactometer bioassays. Analysis of dissected body parts of adults revealed that the pheromone is produced in the lateral accessory glands of the metathoracic scent gland of males only.
Assuntos
Heterópteros/metabolismo , Atrativos Sexuais/síntese química , Comunicação Animal , Animais , Feminino , Hidrocarbonetos/química , Masculino , Espectrometria de Massas , Atrativos Sexuais/metabolismo , Comportamento Sexual Animal , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The male-produced sex pheromone from the Brazilian rice stalk stink bug Tibraca limbativentris is reported. Olfactometer bioassays with sexually mature males and females showed that males attracted females, which suggests that males release a sex pheromone. Males were not attracted to either sex, nor were females attractive to conspecific females. Attraction of the females to males was highest at night. The headspace volatiles collected from male and female bugs were analyzed by gas chromatography (GC) and GC-mass spectrometry. Two male-specific compounds were identified as isomers of 1'S-zingiberenol, whereas a series of defensive compounds were identified in extracts from both sexes. Zingiberenol has three chiral centers, and the nonselective syntheses used produced two groups of isomers, zingiberenol I containing four isomers, namely (1RS,4RS,1'R)-4-(1',5'-dimethylhex-4'-enyl)-1-methylcyclohex-2-en-1-ol, and zingiberenol II containing the other four isomers, namely (1RS,4RS,1'S)-4-(1',5'-dimethylhex-4'-enyl)-1-methylcyclohex-2-en-1-ol. Both groups of stereoisomers were more attractive than hexane controls. The absolute configuration of the insect-produced pheromonal components remains to be elucidated, but the 1'S stereochemistry was established for at least one of the isomers.
Assuntos
Besouros/química , Atrativos Sexuais/química , Animais , Besouros/fisiologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Oryza , Sesquiterpenos , EstereoisomerismoRESUMO
Volatiles compounds collected from the male Neotropical brown stink bug, Euschistus heros (F.), a serious Central and South American soybean pest, have been reevaluated. The proportion of three methyl esters is found to be quite different from previous study. A new blend is proposed as the male-produced stimulatory volatiles based on gas chromatographic-electroantennographic detection (GC-EAD) techniques. The three GC-EAD-active components reproducibly found in volatiles collected from males are methyl (2E,4Z)-decadienoate (53 percent), methyl 2,6,10-trimethyldodecanoate (3 percent), and methyl 2,6,10-trimethyltridecanoate (44 percent) respectively. Males of this hemipteran species needed to reach an age of ~15 days to produce enough male-specific compounds to be detected by capillary column GC equipped with flame ionization detector (FID). The amounts of these three stimulatory volatiles increased with age and appeared to reach a maximum at ~35 days old, with the release rate of ~2.5 mug/day/male and the ratio of these three components seemed not to be affected by aging.
Compostos voláteis obtidos de machos do percevejo marrom Neotropical Euschistus heros (F.), uma das principais pragas da cultura da soja na região da América Central e Sul, foram reavaliados. A proporção dos três ésteres já identificados mostrou-se bem diferente da determinada em estudos anteriores. Uma nova combinação de ésteres metílicos é proposta como voláteis estimulatórios produzidos pelos machos, baseando-se nos resultados obtidos das análises por detecção eletroantenográfica acoplada ao cromatógrafo gasoso (GC-EAD). Os três componentes ativos detectados por CG-EAD nos voláteis coletados da aeração de machos foram os (2E,4Z)-decadienoato de metila (53 por cento), 2,6,10-trimetildodecanoato de metila (3 por cento), e 2,6,10-trimetiltridecanoato de metila (44 por cento). A liberação dos voláteis pelos machos adultos alcança níveis detectáveis para análise por cromatografia gasosa capilar com detector de ionização de chamas quando os insetos estão com aproximadamente 15 dias na fase adulta. A quantidade dos três compostos estimulatórios aumentou com a idade dos percevejos e atingiu um nível máximo de produção com aproximadamente 35 dias de fase adulta. A taxa de liberação desses compostos é aproximadamente de 2,5 mig/macho/dia e a proporção desses três componentes parecem não ser afetada com a idade após a maturidade sexual.
RESUMO
The brown stink bug, Euschistus servus (Say), is abundant throughout most of eastern North America and is commonly found feeding on soybean, mullein, beans, tomatoes, peas, cotton, wheat, corn, tobacco and peach. Color change in E. servus from green to reddish-brown was shown to be an indicator of reproductive diapause. Reddish-brown insects lived longer than green individuals, females laid no eggs, and males did not produce pheromone. The high mortality registered for the green colony of E. servus adults was associated with the physiological cost associated with reproduction. The main pheromone component of this species is methyl 2E,4Z-decadienoate, in agreement with previous work. The first generation of this species develops on noncrop hosts and the second generation often migrates to crops where they may then exceed economic damage thresholds. Traps or trap crops baited with pheromone to catch or concentrate females for destruction, or even a pheromone-based disruption of orientation behavior to decrease the mating success, are possible semiochemical techniques to suppress populations of second generation of E. servus.
O percevejo marrom neártico, Euschistus servus (Say), é abundante em toda a Região Leste da América Norte e é encontrado geralmente alimentando-se em culturas de soja, mullein, feijão, tomate, ervilha, algodão, trigo, milho, tabaco e pêssego. A mudança da coloração de verde para marrom demonstrou ser um indicativo de diapausa reprodutiva em E. servus. Os insetos de coloração marrom viveram por mais tempo que os indivíduos de coloração verde, as fêmeas não colocaram nenhum ovo, e os machos não produziram feromônio sexual. A alta taxa de mortalidade registrada para a colônia de indivíduos verdes de adultos de E. servus foi interpretada como custo fisiológico associado à reprodução. O componente principal do feromônio dessa espécie foi confirmado como 2E, 4Z-decadienoato de metila, de acordo com trabalho realizado anteriormente. A primeira geração dessa espécie se desenvolve em plantas silvestres e a segunda geração migra frequentemente para culturas onde podem exceder os níveis de dano econômico. Porém, técnicas semioquímicas podem ser empregadas para suprimir populações da segunda geração de E. servus. Armadilhas ou culturas armadilhas iscadas com feromônio podem capturar ou concentrar as fêmeas da espécie para serem destruídas, ou mesmo a técnica do confundimento, pode ser utilizada para diminuir a possibilidade de acasalamentos.