Pollination by insects is an essential service for the conservation of plant biodiversity, since it increases the rate of fertilization of flowers and therefore increases the quality and quantity of seeds and fruits. In tropical regions, native plants depend heavily on stingless bees as pollinators since before the introduction of the European honey bee Apis mellifera. However, like for many other insect species worldwide, anthropogenic actions represent a true threat to stingless bee populations. In this article, we review the works that evaluated the potential negative impacts of human activities on populations of stingless bees. The studies constitute a strong body of evidence that stingless bee populations are at risk of decline around the world due to threats including habitat loss, agrochemicals, competition for resources, climate change, and the introduction of exotic species, including pathogens.

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The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is an important insect pest of sorghum and sugarcane crops throughout the United States and Mexico. In 2013, its capacity for crop destruction of these 2 commodities amounted to millions of dollars. Currently, no artificial diets are available that can be used for in vitro screening of potential bioactive substances toxic to this aphid species. The objective of our work, reported herein, was to evaluate liquid artificial diets for use in such in vitro screening bioassays. We evaluated a diet originally developed for the green peach aphid (Myzus persicae Sulzer [Hemiptera: Aphididae]) and another for the whitefly (Bemisia argentifolii Bellow and Perring [Hemiptera: Aleyrodidae]). Melanaphis sacchari did not survive on the M. persicae diet, whereas about 46% survived on the whitefly diet that contained 30% sucrose and 5% yeast extract during the 10 d trial. Further tests then were conducted to determine if sucrose alone at concentrations of 15, 30, and 50% would be a sufficient artificial diet. We found that M. sacchari survival at 10 d post ingestion was greatest (87%) when the diet contained 30% sucrose alone. This solution represented the best diet option for use for in vitro toxicological screening bioassays for the sugarcane aphid.

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