The effects of mowing milkweeds in areas visited by monarch butterflies (Danaus plexippus L., Nymphalidae) were studied by counting the eggs and larvae on regenerating common milkweeds (Asclepias syriaca L., Apocyanaceae) in five adjacent mowed hayfields in northern Virginia in late summer 2015. At the same time monarch larvae were counted on mature senescent common milkweeds in unmowed areas adjacent or near to the mowed hayfields. Milkweeds supported populations of immature monarchs in both habitat types with initially many eggs and early instars found on regenerating plants in the mowed hayfields while late instars dominated the unmowed older milkweeds. As September proceeded, the censuses revealed an increase in the numbers of late instars on the mowed regenerating milkweeds whereas the abundance of larvae declined sharply on the older senescing milkweeds, many of which had lost all or most of their leaves. The study showed that late season mowing of hayfields provided adult female monarch butterflies with rejuvenated resources for reproduction during a time when senescent milkweeds were becoming unsuitable for the monarch larvae. Our findings have implications for managing land in ways to benefit monarchs and for mitigating the widespread decline of milkweeds, although the research raises several caveats and more needs to done to measure the fitness of monarch adults that are produced late in the flight season of the butterfly.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.