Impacts of the insecticide thiamethoxam on the native stingless bee Plebeia catamarcensis (Hymenoptera, Apidae, Meliponini).

Agricultural production and the indiscriminate use of insecticides such as thiamethoxam have put at risk the biodiversity and ecosystem services provided by bees, including native stingless species. Since most of the native species do not present economic importance, they may suffer "silent extinction", due to lack of monitoring of their colonies. Therefore, this study aimed to determine the lethal and sublethal concentrations of the insecticide thiamethoxam, with evaluation of its sublethal effects on mobility, in the stingless bee Plebeia catamarcensis (Holmberg, 1903).

Effects of chronic exposure to sublethal doses of neonicotinoids in the social wasp Polybia paulista: Survival, mobility, and histopathology.

Several studies have investigated the consequences of exposure to neonicotinoids in honeybees. Given the lack of studies concerning the consequences of exposure of social wasps to neonicotinoids, as well as the ecological importance of these insects, the objective of this study was to test the hypothesis that chronic exposure to sublethal concentrations of thiamethoxam decreases survival and mobility by causing damage to the brain and midgut of the social wasp Polybia paulista. The wasps were exposed to different concentrations of thiamethoxam, in order to obtain the mean lethal concentration (LC), which was used as a reference for calculation of two sublethal concentrations (LC and LC) employed in subsequent experiments.

Lethal and Sublethal Dose of Thiamethoxam and Its Effects on the Behavior of a Non-target Social Wasp.

In the last few years, with the increase in agricultural productivity, there has also been an increase in the use of insecticides to combat insects considered pests. However, these chemical compounds end up affecting nontarget insects that also interact with the crops. Studies have shown that social bees are among the insects that are suffering most from the effects of these compounds, resulting in negative ecological and economic impacts, considering that these insects provide pollination services in ecosystems.

Magnetic nanoparticles in the body parts of Polistes versicolor and Polybia paulista wasps are biomineralized: evidence from magnetization measurements and ferromagnetic resonance spectroscopy.

The detection of the geomagnetic field by animals to use as a cue in homing and migration is known as magnetoreception. The ferromagnetic hypothesis explains magnetoreception assuming that magnetic nanoparticles in cellular structures are used as magnetic field transducers. Considering magnetoreception in social insects, the most studied has been the honeybee Apis mellifera and only in two wasp species (Vespa orientalis and Polybia paulista) have been shown a magnetosensitive behavior.

Is the social wasp Polybia paulista a silent victim of neonicotinoid contamination?

Neonicotinoids are among the chemicals most widely used against insects considered agricultural pests, although they may also affect nontarget species, as has been reported for social bees. Social wasps are recognized as efficient predators of larvae of other insects, including pest species, so they may have contact with insecticides, at least indirectly. However, to date, there have been no studies investigating the consequences for social wasps of the use of neonicotinoids.

The complex nest architecture of the Ponerinae ant Odontomachus chelifer.

In social insects, nests are very important structures built to provide a protected microhabitat for immature development and food storage and are the places where most interactions between all members of a colony occur. Considering that nest architecture is an important behavioural trait that can clarify essential points of the social level of the species, here we describe the architectural model of the Ponerinae ant Odontomachus chelifer. Five subterranean nests were excavated; one of them filled with liquid cement for extraction of casts of chambers, shafts and tunnels.