Revisiting the male-produced aggregation pheromone of the lesser mealworm, Alphitobius diaperinus (Coleoptera, Tenebrionidae): identification of a six-component pheromone from a Brazilian population

The lesser mealworm, Alphitobius diaperinus Panzer 1797 (Coleoptera: Tenebrionidae), is a cosmopolitan insect pest affecting poultry production. Due to its cryptic behavior, insecticide control is usually not efficient. Thus, sustainable and effective methods would have an enormous and positive impact in poultry production. The aim of this study was to confirm the identity of the male-produced aggregation pheromone for a Brazilian population of A. diaperinus and to evaluate its biological activity in behavioral assays. Six male-specific compounds were identified: (R)-limonene (1), (E)-ocimene (2), 2-nonanone (3), (S)-linalool (4), (R)-daucene (5), all described before in an American population, and a sixth component, (E,E)-α-farnesene (6), which is apparently exclusive to a Brazilian population. Y-Tube bioassays confirmed the presence of a male-produced aggregation pheromone and showed that all components need to be present in a similar ratio and concentration as emitted by male A. diaperinus to produce a positive chemotactic response

Electrophysiologic and behavioral responses mediated by volatiles involved in the repellency of Apis mellifera (Lepeletier) (Hymenoptera Apidae)

Repellent volatiles to insects might be an important tool for management of bees in areas which the presence of these organisms is not required. This study aimed to evaluate the electroantennal and behavioral responses of Africanized honeybees (workers), Apis mellifera (Lepeletier) (Hymenoptera Apidae), at different ages, to benzaldehyde (BA) and methyl anthranilate (MA) and to evaluate the potential repellency of these compounds under field conditions. Laboratory tests were conducted to study electroantennographic responses (mV) and chemotactic behavior of worker bees aged 1-5 (young) and 20-30 (old) days in four choice olfactometer. Electrophysiological responses to each compound did not differ between young and old workers. Bees antennae (young) triggered significantly greater responses to BA, in the older ones, a higher response was observed to MA, both compared to control (ethanol). The threshold response to BA and MA was achieved at 10 µg/µL, both compounds repelled bees at the same dose in olfactometer. Treatments with BA and MA, in field conditions, were less visited by scouter honey bees than those without these compounds (control)

Respostas quimiotáxicas de Orius insidiosus (Say) ao complexo Nicotiana tabacum L., Myzus persicae (Sulzer) e fitormônios

Orius insidiosus (Say) (Hemiptera: Anthocoridae) is one of the major predators of small arthropods such as thrips, aphids, mite, eggs and small caterpillars. It is a polyphagous specie, and can be find in many agrosystems. This predator is used globally to control populations of aphids, which can be vectors of several viruses that occur in tobacco. The predator's survival may be associated with their ability for use chemical cues from the prey or plants damaged by herbivores to locate feeding sites. The emission of volatile chemical compounds is one of the defense mechanisms of plants to attract natural enemies. The emission of volatiles from plants associated with indirect defense is used to attract natural enemies and can also be activated in the presence of phytohormones such as methyl jasmonate and salicylic acid. This work aimed to evaluate the chemotactic responses of O. insidiosus females against plants Nicotiana tabacum L. (Solanaceae) infested and not infested with Myzus persicae (Sulzer) (Hemiptera: Aphididae), odor of aphid and plants sprayed with salicylic acid and methyl jasmonate. The females were evaluated in a double-choice olfactometer, individually, exposed to each of the treatments, contrasting with the control in a labor room (25 ± 5 ºC, 60 ± 10% RH). Females were only attracted to plants when they were infested (p 0.05). Volatile compounds produced by tobacco plants under the action of herbivory of M. persicae attract O. insidiosus indicating that this species uses synomones as search strategy and location of prey.Orius insidiosus (Say) (Hemiptera: Anthocoridae), conhecido como um dos principais predadores de pequenos artrópodes como tripes, pulgões, ácaros e pequenas lagartas sendo uma espécie polífaga, que pode ser encontrada em diferentes agroecossistemas. Este predador é mundialmente usado para controle de populações de pulgões, os quais podem ser vetores de diversas viroses que ocorrem em tabaco. A sobrevivência de predadores pode estar associada à sua capacidade de utilizar pistas químicas provenientes das presas ou das plantas em herbivoria para localizar sítios de alimentação. A emissão de voláteis de defesa indireta de plantas é um dos mecanismos utilizado para atrair inimigos naturais e também pode ser ativado na presença de fitormônios, como metil jasmonato e ácido salicílico. Este trabalho teve como objetivo avaliar as respostas quimiotáxicas de fêmeas de O. insidiosus frente a plantas Nicotiana tabacum L. (Solanaceae) infestadas ou não com Myzus persicae (Sulzer)(Hemiptera:Aphididae), ao odor do pulgão e a plantas aspergidas com ácido salicílico e metil jasmonato. As fêmeas foram avaliadas em olfatômetro de dupla escolha, expostas, individualmente, a cada um dos tratamentos contrastando com o controle em sala climatizada (25 ± 5 ºC, 60 ± 10% UR). As fêmeas somente foram atraídas para plantas quando estavam infestadas (p 0,05). Voláteis produzidos por plantas de tabaco sob a ação da herbivoria de M. persicae atraem O. insidiosus o que evidencia que esta espécie utiliza sinomônios como estratégia de busca e localização de presas