Professor University of Wisconsin-Madison Madison, Wisconsin, United States
Abstract: Lady beetles are charismatic predators in agricultural systems that often contribute to natural pest control. In controlled environments, lady beetles can be reliable predators of target prey but foraging preferences in real landscapes are harder to predict. In particular, the effects of local habitat (e.g. crop fields vs. natural areas) and landscape context on lady beetle diets, and how these may vary by species, is not well studied. Understanding the extent to which environmental variables may enhance or interrupt predation services by insect natural enemies is necessary for the design of pest-suppressive landscapes. To address these knowledge gaps, we measured the diets of native and introduced lady beetles collected across southern Wisconsin, USA using DNA metabarcoding with next generation sequencing. 508 individual beetles from 8 species (4 native, 4 introduced) were collected in six different habitat types (4 crops, grasslands, and woodlands) during the summers of 2019 and 2021. DNA was extracted from whole beetles using QIAGEN DNEasy blood and tissue kits and amplified with the ANML primer pair. Preliminary results show that about one third of samples were positive for at least one non-Coccinellid arthropod species, with a maximum of 5 species per beetle. The most common prey taxa observed were flies (Diptera) and true bugs (Hemiptera). Beetle communities collected from landscapes with greater habitat diversity were associated with greater prey richness. These results can help inform conservation strategies for particular cropping systems to promote the natural enemy species that will be the most effective pest control agents.
