ABSTRACT
BACKGROUND: The stingless bee, Trigona spinipes, is an important pollinator of numerous native and cultivated plants. Trigona spinipes populations can be negatively impacted by insecticides commonly used for pest control in crops. However, this species has been neglected in toxicological studies. Here we observed the effects of seven insecticides on the survival of bees that had fed directly on insecticide-contaminated food sources or received insecticides via trophallactic exchanges between nestmates. The effects of insecticides on flight behavior were also determined for the compounds considered to be of low toxicity. RESULTS: Imidacloprid, spinosad and malathion were categorized as highly toxic to T. spinipes, whereas lambda-cyhalothrin, methomyl and chlorfenapyr were of medium to low toxicity and interfered with two aspects of flight behavior evaluated here. Chlorantraniliprole was the only insecticide tested here that had no significant effect on T. spinipes survival, although it did interfere with one aspect of flight capacity. A single bee that had ingested malathion, spinosad or imidacloprid, could contaminate three, four and nineteen other bees, respectively via trophallaxis, resulting in the death of the recipients. CONCLUSION: This is the first study to evaluate the ecotoxicology of a range of insecticides that not only negatively affected T. spinipes survival, but also interfered with flight capacity, a very important aspect of pollination behavior. The toxicity of the insecticides was observed following direct ingestion and also via trophallactic exchanges between nestmates, highlighting the possibility of lethal effects of these insecticides spreading throughout the colony, reducing the survival of non-foraging individuals. © 2023 Society of Chemical Industry.
Subject(s)
Hymenoptera , Insecticides , Nitro Compounds , Humans , Bees , Animals , Insecticides/toxicity , Malathion/toxicity , Neonicotinoids/toxicity , EatingABSTRACT
Humulus lupulus (Cannabaceae) is a climbing herbaceous plant with perennial production, intended mainly for the brewing industry. H. lupulus is widely cultivated in temperate regions; hop cultivars have shown good adaptation in regions of Brazil. In a hop-growing area in São Mateus, the state of Espírito Santo, leaf wilting and galling of the root system was observed. Soil and root samples were taken to the laboratory and processed, and the nematodes extracted from the Meloidogyne genus were identified by morphology, morphometry, and biochemical analysis. According to the results, the species identified in the hop roots was Meloidogyne morocciensis. This is the first report of H. lupulus as host of M. morocciensis.
ABSTRACT
Eibesfeldtphora tonhascai Brown (Diptera: Phoridae) is a natural enemy of Atta sexdens Linnaeus and Atta laevigata Smith and is considered a promising candidate for the biological control of these ants. The aim of this study was to verify if E. tonhascai has a preference for specific sizes of A. sexdens foragers and whether this parasitoid demonstrated host species preference when comparing parasitism of A. sexdens and A. laevigata. Worker ants were classified into four different size groups and introduced into an attack arena with one E. tonhascai female. To verify host species preference, both A. sexdens and A. laevigata workers were placed in the attack arena together with one E. tonhascai female. A no-choice test was also performed, when each ant species was offered to a phorid female at different times. Eibesfeldtphora tonhascai performed the highest number of inspection flights, attempted attacks, and actual attacks against A. sexdens workers with a cephalic capsule size of 3-5 mm. When comparing attacks on A. sexdens and A. laevigata workers, they were equally inspected, attacked, and the total parasitism rates were similar. However, the phorid adult emergence rate was significantly higher in the A. sexdens parasitized workers. We conclude that E. tonhascai females express preference for parasitizing larger hosts (cephalic capsule width of 3-5 mm), but do not display a preference for host species when comparing A. sexdens versus A. laevigata, and thus can similarly contribute to both leafcutter ants' natural biological control.
