RESUMO
Historically, males have frequently been portrayed as the manipulative and deceptive gender, while females are often seen as adopting a coy and passive role. In this context, it is proposed that males use a terminal investment strategy, misleading females about their true poor condition, while females passively opt to mate with these deceptive males. However, we hypothesize that females in suboptimal condition may also engage in a terminal investment strategy by mimicking or enhancing their attractiveness to match that of females in better conditions. We studied this hypothesis in Tenebrio molitor, by subjecting females to three varying doses of lipopolysaccharides of Escherichia coli (LPS; 0.25, 0.5, or 1 mg ml-1), or three doses of the pro-oxidant Paraquat (PQ; 20, 40 or 80 mM), and subsequently assessing their survival and attractiveness to males. The LPS treatments and 20 mM of PQ had no significant effect on the survival or attractiveness of the females. However, females treated with 40 or 80 mM PQ survived fewer days compared to the control group. Those injected with 40 mM were more attractive than their control counterparts, while those treated with 80 mM were less attractive. Since the identical doses of LPS, which induce terminal investment in males, had no effect on females, we suggest sexual dimorphism in terminal investment. Furthermore, similar to males, if the stressor reaches a sufficiently high level, the signal becomes honest. These findings highlight how the quantity of stressors influences support for the terminal investment strategy in both males and females. Notably, this study challenges prevailing notions regarding gender roles in sexual selection, indicating that females, not just males, conceal their poor condition to attract mating partners.
Assuntos
Lipopolissacarídeos , Comportamento Sexual Animal , Feminino , Masculino , Animais , Comportamento Sexual Animal/efeitos dos fármacos , Comportamento Sexual Animal/fisiologia , Lipopolissacarídeos/farmacologia , Tenebrio/fisiologia , Tenebrio/efeitos dos fármacos , Paraquat/farmacologiaRESUMO
Cryptococcosis is an opportunistic systemic mycosis whose treatment is limited to three drugs. In this work, we evaluated the antifungal activity of a hexane extract (HE) from Spondias tuberosa leaves against Cryptococcus neoformans and Cryptococcus gattii. Minimal inhibitory concentrations (MIC) were determined, and putative mechanisms were evaluated by flow cytometry. In addition, an in vivo infection assay was performed using Tenebrio molitor larvae. Treatment with HE inhibited the growth of standard and clinical isolates of C. neoformans and C. gattii (MICs ranging from 0.78 to 3.12mg/mL), significantly (P<0.05) increased mitochondrial superoxide anion levels, and induced mitochondrial membrane depolarization, loss of lysosomal membrane integrity, and phosphatidylserine externalization. The mean survival time of C. gattii-infected T. molitor larvae significantly (P<0.05) increased from 1.225 days in control to 3.067 and 3.882 days in HE-treated groups (78 and 156mg/kg, respectively). In conclusion, HE showed anticryptococcal activity, induced mitochondrial and lysosomal damage in yeast cells, and exhibited anti-infective action against C. gattii in T. molitor larvae.
Assuntos
Anacardiaceae/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Criptococose/tratamento farmacológico , Hexanos/química , Animais , Antifúngicos/efeitos adversos , Antifúngicos/uso terapêutico , Criptococose/patologia , Cryptococcus gattii/citologia , Cryptococcus gattii/efeitos dos fármacos , Cryptococcus gattii/ultraestrutura , Cryptococcus neoformans/citologia , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/ultraestrutura , Hexanos/farmacologia , Humanos , Larva/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/fisiologia , Testes de Sensibilidade Microbiana , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Fitoterapia , Extratos Vegetais/química , Tenebrio/efeitos dos fármacos , Tenebrio/crescimento & desenvolvimento , Testes de ToxicidadeRESUMO
Alphitobius diaperinus is an important pathogen with worldwide distribution that causes severe economic loss of efficiency in broilers. This study evaluates the potential of organic extracts of two strains entomopathogenic fungus Beauveria bassiana (CG71 and UNI40) as a biocontrol agent on A. diaperinus and promotes the phytochemical investigation. The effective percentages of mortalities were 95.97% (UNI40 methanolic extract), 69.23, 64.64, and 50.39% (CG 71 methanolic, ethyl acetate and butanol extracts). However, there was a decrease in the lesser mealworms susceptibility in relation to the use of insecticides and extracts. The metabolites 5-hydroxymethyl-2-furanoic acid, dipicolinic acid and monomethyl dipicolinate were isolated from ethyl acetate extract, and ß-adenosine of butanolic extract of B. bassiana CG 71. In addition, the cyclodepsipeptides were identified in methanolic extracts of the two strains. The insecticide activity results indicated that the B. bassiana extracts are an alternative to A. diaperinus control.
Assuntos
Beauveria/patogenicidade , Agentes de Controle Biológico/isolamento & purificação , Besouros/efeitos dos fármacos , Animais , Agentes de Controle Biológico/farmacologia , Galinhas , Inseticidas , Tenebrio/efeitos dos fármacosRESUMO
This study evaluated the insecticidal activity of garlic, Allium sativum Linnaeus (Amaryllidaceae) essential oil and their principal constituents on Tenebrio molitor. Garlic essential oil, diallyl disulfide, and diallyl sulfide oil were used to compare the lethal and repellent effects on larvae, pupae and adults of T. molitor. Six concentrations of garlic essential oil and their principal constituents were topically applied onto larvae, pupae and adults of this insect. Repellent effect and respiration rate of each constituent was evaluated. The chemical composition of garlic essential oil was also determined and primary compounds were dimethyl trisulfide (19.86%), diallyl disulfide (18.62%), diallyl sulfide (12.67%), diallyl tetrasulfide (11.34%), and 3-vinyl-[4H]-1,2-dithiin (10.11%). Garlic essential oil was toxic to T. molitor larva, followed by pupa and adult. In toxic compounds, diallyl disulfide was the most toxic than diallyl sulfide for pupa > larva > adult respectively and showing lethal effects at different time points. Garlic essential oil, diallyl disulfide and diallyl sulfide induced symptoms of intoxication and necrosis in larva, pupa, and adult of T. molitor between 20-40 h after exposure. Garlic essential oil and their compounds caused lethal and sublethal effects on T. molitor and, therefore, have the potential for pest control.
Assuntos
Inseticidas/farmacologia , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Tenebrio/efeitos dos fármacos , Animais , Alho , Larva/efeitos dos fármacos , Pupa/efeitos dos fármacosRESUMO
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.
Assuntos
Quimiotaxia , Feromônios/química , Tenebrio/efeitos dos fármacos , Monoterpenos Acíclicos , Alcenos/química , Animais , Comportamento Animal , Brasil , Compostos Bicíclicos com Pontes/química , Cromatografia Gasosa , Cicloexenos/química , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Cetonas/química , Limoneno , Masculino , Monoterpenos/química , Olfatometria , Sesquiterpenos/química , Terpenos/química , Compostos Orgânicos Voláteis/químicaRESUMO
Trade-offs are a central tenet in the life-history evolution and the simplest model to understand it is the "Y" model: the investment of one arm will affect the investment of the other arm. However, this model is by far more complex, and a "branched Y-model" is proposed: trade-offs could exist within each arm of the Y, but the mechanistic link is unknown. Here we used Tenebrio molitor to test if Juvenile Hormone (JH) could be a mechanistic link behind the "branched Y-model". Larvae were assigned to one of the following experimental groups: (1) low, (2) medium and (3) high doses of methoprene (a Juvenile Hormone analogue, JHa), (4) acetone (methoprene diluents; control one) or (5) näive (handled in the same way as other groups; control two). The JHa lengthened the time of development from larvae to pupae and larvae to adults, resulting in adults with a larger size. Males with medium and long JHa treatment doses were favored with female choice, but had smaller testes and fewer viable sperm. There were no differences between groups in regard to the number of spermatozoa of males, or the number of ovarioles or eggs of females. This results suggest that JH: (i) is a mechanistic link of insects "branched Y model", (ii) is a double ended-sword because it may not only provide benefits on reproduction but could also impose costs, and (iii) has a differential effect on each sex, being males more affected than females.
Assuntos
Hormônios Juvenis/fisiologia , Modelos Biológicos , Reprodução , Tenebrio/crescimento & desenvolvimento , Animais , Evolução Biológica , Feminino , Hormônios Juvenis/farmacologia , Larva/efeitos dos fármacos , Masculino , Metoprene/farmacologia , Pupa/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Reprodução/fisiologia , Comportamento Sexual Animal/efeitos dos fármacos , Espermatozoides/citologia , Espermatozoides/efeitos dos fármacos , Tenebrio/efeitos dos fármacosRESUMO
Linear diterpenes isolated from aerial parts of Baccharis thymifolia ( 1- 3) were tested for insect growth inhibitory activity against Tenebrio molitor larvae. Compounds 4- 16 were prepared by various chemical transformations. The diterpenes 6,10-( E,E)-thymifodioic acid ( 1), the butenolide 3, and the derivatives 4, 11, and 14 produced developmental deficiencies in assays using topical application on fifth instar larvae of T. molitor. Compound 3 is a new natural product.
Assuntos
Baccharis/química , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Inseticidas/isolamento & purificação , Inseticidas/farmacologia , Plantas Medicinais/química , Animais , Argentina , Diterpenos/química , Inseticidas/química , Larva/efeitos dos fármacos , Estrutura Molecular , Tenebrio/efeitos dos fármacosRESUMO
Os objetivos deste trabalho foram avaliar os efeitos imediato e latente da temperatura do grão, durante a pulverização, sobre a persistência e eficácia biológica do inseticida bifentrina, no controle de Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) e Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Para tal, bifentrina foi pulverizada em grãos de milho com diferentes temperaturas (25, 30, 35, 40 e 45°C). Para avaliação da sua persistência fez-se a extração e análise do resíduo a cada 30 dias, iniciando logo após a pulverização do inseticida, até os 90 dias de armazenamento. Para avaliação da eficácia biológica, 20 adultos de cada espécie foram colocados em placasde-petri contendo grãos tratados, sendo mantidas em câmaras do tipo B.O.D., a 27 °C e 55 por cento de UR durante 48 horas. Estas avaliações foram realizadas em intervalos de 15 dias, com início logo após a pulverização e término aos 90 dias de armazenamento. Observou-se que tanto a persistência quanto a eficácia biológica da bifentrina reduziram à medida que o período de armazenamento e a temperatura do grão aumentaram. Observou-se, ainda, que S. zeamais apresentou maior tolerância à bifentrina, que T. castaneum.
Assuntos
Animais , Inseticidas/farmacologia , Piretrinas/farmacologia , Temperatura , Tenebrio/efeitos dos fármacos , Gorgulhos/efeitos dos fármacos , Zea mays/parasitologiaRESUMO
The objective of this work was to evaluate the immediate and latent effects of the grain temperature, during the spraying process, on the persistence and biological efficacy of the biphenthrin insecticide against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). For such, biphenthrin was sprayed on the grain at the temperatures: 25, 30, 35, 40 and 45 degrees C. To access the persistence of biphenthrin, insecticide residue analyses were carried out monthly, just after spraying until 90 days of storage. To evaluate the biological efficacy of biphenthrin, 20 adults of each species were placed in petri dishes with sprayed grain, and kept in climate cabinets under 27 degrees C and 55% of RH, during 48h. Evaluations were done every 15 days, starting just after spraying and finishing at 90 days of storage. Both persistence and biological efficacy of biphenthrin reduced as storage time and grain temperatures increased. Additionally, S. zeamais was more tolerant to biphenthrin than T. castaneum.
Assuntos
Inseticidas/farmacologia , Piretrinas/farmacologia , Temperatura , Tenebrio/efeitos dos fármacos , Gorgulhos/efeitos dos fármacos , Zea mays/parasitologia , AnimaisRESUMO
Three new neoclerodane diterpenoids, salvinorins D-F (4-6), have been isolated from the leaves of Salvia divinorum. The structures were elucidated by chemical and spectroscopic methods, particularly 1D and 2D NMR. A simplified isolation method using chromatography on activated carbon also gave improved yields of the controlled substance salvinorin A (1) and of salvinorin C (3).