Low doses of ivermectin cause sensory and locomotor disorders in dung beetles

Ivermectin is a veterinary pharmaceutical generally used to control the ecto- and endoparasites of livestock, but its use has resulted in adverse effects on coprophilous insects, causing population decline and biodiversity loss. There is currently no information regarding the direct effects of ivermectin on dung beetle physiology and behaviour. Here, based on electroantennography and spontaneous muscle force tests, we show sub-lethal disorders caused by ivermectin in sensory and locomotor systems of Scarabaeus cicatricosus, a key dung beetle species in Mediterranean ecosystems. Our findings show that ivermectin decreases the olfactory and locomotor capacity of dung beetles, preventing them from performing basic biological activities. These effects are observed at concentrations lower than those usually measured in the dung of treated livestock. Taking into account that ivermectin acts on both glutamate-gated and GABA-gated chloride ion channels of nerve and muscle cells, we predict that ivermectin’s effects at the physiological level could influence many members of the dung pat community. The results indicate that the decline of dung beetle populations could be related to the harmful effects of chemical contamination in the dung.

Export and import market-specific characteristics. How they drive the decision to trade and how much

Using a rich firm-level dataset on the Italian manufacturing industry, this paper provides a comprehensive analysis of the role that firms and market characteristics play in shaping firms’ trade activities. We enhance the previous analyses by considering firms’ engagement in international transactions, by focusing on either exports or imports. We show that the determinants of a firm’s export participation and value across countries also drive import behavior. Our research is consistent with the presence of country-specific sunk costs and with a qualitatively similar role of gravity forces and other country attributes on both sides of trading activities. Our evidence, however, militates in favor of a framework where variations in market characteristics have a larger impact on imports than exports.