D3076: Assessing the presence of kleptopharmacophagy in Danaus plexippus

 Butterflies in the Danainae have been observed consuming sap from withered plant material, with publications dating back to the 1980s, leading to the discovery of nuptial gift-giving of polyphenol alkaloids in these species. In 2021, an observation indicated a competing behavior, kleptopharmacophagy, entailing one organism stealing another's stored chemicals through cannibalism. This behavior was observed in just a few species of the Danainae subfamily, including Euploea algae, Ideopsis juventa, and Danaus ismare. These organisms are seen cutting open caterpillars to extract hemolymph with their proboscis. No published follow-up studies have been conducted to address the prevalence or implications of this behavior throughout the Danainae. The objectives of this preliminary investigation are to establish a methodology for identifying kleptopharmacophagy across different species and assess its potential occurrence in Danaus plexippus through field observations. We hypothesize that kleptopharmacophagy is a well-conserved behavior across the Danainae subfamily, with many members exhibiting it. Field sites were established based on physical observations of D. plexippus adults, larvae, or larval herbivory. Field sites were monitored weekly for signs of kleptopharmacophagy. Any sites that had injured or dead caterpillars from lacerations were documented as proposed incidents. Cameras were set up at sites with proposed incidents to capture direct evidence of the behavior. Preliminary findings suggest behavioral cues indicative of kleptopharmacophagy in monarch butterflies, Danaus plexippus, warranting further investigation. Uncovering the prevalence of kleptopharmacophagy in a well-studied species like the monarch butterfly may offer insights into broader ecological and evolutionary contexts.