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The Effects of Mosquito-Control Applications of Permethrin on Monarch Butterfly ( Danaus plexippus ) Larvae. By Sara Brinda 2003-2004. http://www.hwcn.org/link/hmm/mbcat.JPG. Background. Permethrin (Mosquito spray) Pyrethroid pesticide Sprayed in ULV form as mosquito adulticide
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The Effects of Mosquito-Control Applications of Permethrin on Monarch Butterfly (Danaus plexippus) Larvae By Sara Brinda 2003-2004 http://www.hwcn.org/link/hmm/mbcat.JPG
Background • Permethrin (Mosquito spray) • Pyrethroid pesticide • Sprayed in ULV form as mosquito adulticide • Applied to wooded areas, where milkweed can grow
Background • Monarchs: non-target insect • Larvae (caterpillars) are terrestrial • Only eat milkweed (Asclepias) http://www.mbsf.org/news.html
Background • Little research conducted on effect on non-target invertebrates • Only peer-reviewed field study (Jensen et al): immediate mortality in aquatic and night-flying insects
Materials and Methods: Part I • Common milkweed (A. syriaca) collected from permethrin-treated areas • Larvae fed with treated milkweed leaves • Three variables • Days between spraying and initial exposure • Days spent on treated leaf • Beginning instar
Hypotheses (Part I) • Milkweed collected from permethrin-treated areas will have lethal effect on monarch larvae • Larval mortality rates will be higher: • Leaves treated more recently with permethrin • Exposed to treated leaves for greater period of time • Exposed to milkweed during earlier instars (growth stages)
Materials and Methods: Part II • Leaves treated in lab with oil solution, 0.1% solution, or 0.5% solution • Leaves fed to monarchs for entire lifetime • Larval mass and instar monitored daily • Adult mass recorded
Hypotheses (Part II) • Larvae exposed to sublethal solution will be affected: • Slower development time • Smaller adult mass • Oil diluent will have no effect
Further Study • Permethrin effectiveness on mosquitoes vs. nontargets • How effective • Effective for how long? • More research needed on mosquito adulticide effects on non-target insects
Acknowledgements • Dr. Karen Oberhauser • Everyone who worked in the lab this summer • Metropolitan Mosquito Control District, especially Dr. Stephen Manwieler • Ms. Lois Fruen • Team Research • Beth Brinda
The Effects of Mosquito-Control Applications of Permethrin on Monarch Butterfly (Danaus plexippus) Larvae http://www.hwcn.org/link/hmm/mbcat.JPG By Sara Brinda 2003-2004