Pesticides detected in two urban areas have implications for local butterfly conservation.

Human-managed green spaces in urban landscapes have become important focal points for insect conservation, partly because of the desirable insect diversity that these areas support, and also because exposure to nature is important for human health and wellbeing. An important issue in insect conservation is the extent to which non-pest insects are impacted by pesticide applications, but this has been relatively less examined outside of agricultural landscapes. Here, we investigated green spaces, including parks and private yards, in two urban areas (Sacramento, California, and Albuquerque, New Mexico), asking if larval host plants for butterflies in the two regions contained herbicides, insecticides, and fungicides.

Pyrethroid insecticides implicated in mass mortality of monarch butterflies at an overwintering site in California.

Since the 1980s, monarch butterfly (Danaus plexippus plexippus) populations across North America have declined by 80-95%. Although several studies have implicated pesticides as a contributing factor to their population declines, our understanding of monarch exposure levels in nature remains limited. In January 2024, a mass mortality event near an overwintering site in Pacific Grove, California, USA, provided an opportunity to analyze dead overwintering monarch butterflies for pesticide residues.

Colorimetric Detection of Fentanyl Powder on Surfaces Using a Supramolecular Displacement Assay.

Fentanyl is a potent synthetic opioid with an alarmingly low lethal dosage of 2 mg. The equipment necessary to detect fentanyl in field settings (e.g.