Characteristics of urban milkweed gardens that influence monarch butterfly egg abundance

The eastern population of monarch butterflies (Danaus plexippus) has dramatically declined in the last few decades, which is largely attributed to a loss of milkweed habitat in agricultural areas. Residential land in metropolitan areas has the potential to provide a significant source of the milkweed needed to support the monarch population. To examine if and how urban milkweed patches can support monarch butterflies, we worked with community scientists in the Chicago metropolitan area to monitor monarch eggs and caterpillars in yards and community gardens. We hypothesized that the largest numbers of eggs (i.e. gardens that were most attractive to monarchs) would be observed in patches that were older, had a high abundance of milkweed, contained more than one species of milkweed including Asclepias syriaca (common milkweed) and/or A. incarnata (swamp milkweed), and had a large diversity of nectar plants. All patches were assessed at their peak egg count each year, which ranged from zero to 170 eggs in a given observation. To determine which characteristics were most influential to egg presence, we examined patches where eggs were present or absent during this peak observation. For abundance, we divided these peak observations into whether or not the egg counts were in the top 20% in a given year, excluding patches where eggs were absent, and assessed their patch characteristics. Our results show that patch age and presence of A. syriaca affected whether patches contained eggs or not. We also found that patches with the largest number of eggs observed tended to have A. syriaca, more milkweed plants, and a higher diversity of blooming plant species. The data we collected from community scientists in the Chicago area has enhanced our understanding of how urban gardeners can create effective breeding habitats for monarch butterflies. By planting Asclepias syriaca within its natural range, along with other native milkweed species and a diverse selection of flowering plants, individuals can create gardens that serve as excellent habitats for monarchs and other pollinators

Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population: Herbicide use and monarch butterflies

1. The size of the Mexican overwintering population of monarch butterflies has decreased over the last decade. Approximately half of these butterflies come from the U.S. Midwest where larvae feed on common milkweed. There has been a large decline in milkweed in agricultural fields in the Midwest over the last decade. This loss is coincident with the increased use of glyphosate herbicide in conjunction with increased planting of genetically modified (GM) glyphosate-tolerant corn (maize) and soybeans (soya). 2. We investigate whether the decline in the size of the overwintering population can be attributed to a decline in monarch production owing to a loss of milkweeds in agricultural fields in the Midwest. We estimate Midwest annual monarch production using data on the number of monarch eggs per milkweed plant for milkweeds in different habitats, the density of milkweeds in different habitats, and the area occupied by those habitats on the landscape. 3. We estimate that there has been a 58% decline in milkweeds on the Midwest landscape and an 81% decline in monarch production in the Midwest from 1999 to 2010. Monarch production in the Midwest each year was positively correlated with the size of the subsequent overwintering population in Mexico. Taken together, these results strongly suggest that a loss of agricultural milkweeds is a major contributor to the decline in the monarch population. 4. The smaller monarch population size that has become the norm will make the species more vulnerable to other conservation threats

Project Leader Survey for Butterfly Citizen Science Projects Support Conservation Activities Among Their Volunteers

Survey data presented as supplementary material for the article "Butterfly Citizen Science Projects Support Conservation Activities Among Their Participants", in press (January 2016). The questionnaire contained questions about project characteristics and strategies and activities that could promote conservation activities among participants

Butterfly Citizen Science Projects Support Conservation Activities among their Volunteers

Citizen science has the potential to provide participants with information about conservation issues and to encourage additional conservation actions. In this case study, we describe the current state of conservation education among butterfly citizen science projects in the United States. To determine the extent to which these citizen science projects are promoting an understanding of, and engagement in, conservation among their participants, we used an online questionnaire to census project leaders and assessed their websites for the presence of educational conservation information. We found that the majority (91%, n = 22) of butterfly citizen science projects in the United States include a conservation focus, and that they are educating their participants about key conservation threats and action strategies. Many are also using personal appeals, behavioral incentives, and the social interactions among participants to encourage their participants to engage in butterfly conservation outside the project. We found room for improvement on educating participants, especially about indirect conservation opportunities such as financial donations and outreach activities. We also suggest more widespread and effective use of project websites to disseminate conservation information

I Didn\u27t Know What Real Science Was or What It Could Be: Citizen Science and Interest in STEM Education and Careers

Using the lens of social cultural career theory (SCCT), the purpose of the present study was to assess the role participation in informal citizen science played in youth\u27s STEM educational and career choices. We examined fourteen student responses to semi-structured interviews and survey instruments from eighteen students for evidence of the SCCT constructs self-efficacy, outcome expectations, personal goals, interest, and learning experiences. Findings from this descriptive study showed positive self-efficacy in STEM courses and careers for youth who participated in an informal citizen science project. Through participation in citizen science, students experienced the relevance of contributing to an authentic science investigation, the rigor of citizen science protocols, and relationships with teacher mentors. Overall, the findings underscore the role of teacher mentors and authentic engagement in science in changing students\u27 perceptions of science. Educational implications are discussed

Misgivings about Environmental Outreach as a Barrier in a Neighborhood Opinion Leader Campaign

We examined socially influential residents’ beliefs about pro-environmental outreach in a Midwestern city, identifying factors influencing willingness to participate in an urban water quality outreach campaign. The sample included self-identified leaders (opinion leaders) residing in neighborhoods surrounding a small urban lake. Participants answered questions about using less salt on sidewalks and driveways, removing leaves from the street before it rains, allowing rainwater to soak into the ground on their property, and encouraging neighbors to do these behaviors. Favorable beliefs about outreach and experience with outreach were associated with greater willingness to do pro-environmental outreach. Favorable beliefs about pro-environmental behaviors and experience with pro-environmental behaviors were not associated with willingness to do pro-environmental outreach. We discuss how understanding opinion leaders’ beliefs about pro-environmental outreach and navigating their misgivings about reaching out to their neighbors can inform campaigns fostering neighborhood water advocacy and outreach.</p

Mate pairing patterns of Monarch butterflies (Danaus plexippus L.) at a California overwintering site

Volume: 52Start Page: 84End Page: 9

Lincoln Brower, champion for monarchs

Lincoln Pierson Brower died in Virginia, USA, on July 17, 2018 at the age of 86. Many of the authors of papers in this special volume worked directly with Lincoln, and all were influenced by his work. In particular, for the past three decades, Lincoln worked extensively with his wife Linda Fink, who helped him in field research, in discussing monarch biology, and in critiquing all his written work. Multiple eulogies to Lincoln have been published; here, we describe ways in which Lincoln influenced us as scientists and the worlds of monarch science and conservation, from early in his career until its end

Does chemistry make a difference? Milkweed butterfly sequestered cardenolides as a defense against parasitoid wasps

Plant allelochemicals have important roles in plant defense as well as ecological and co-evolutionary dynamics within tri-trophic systems of plants, herbivores, and natural enemies. Milkweed butterflies represent a model system for chemical ecology because they sequester cardenolides semi-proportionally to the concentration in their host plants, yet little is known about the role of sequestered cardenolides in interactions with invertebrate natural enemies. We experimentally tested the preference and performance of two species of parasitic wasps (Pteromalus cassotis Walker and Pteromalus puparum Linnaeus) on milkweed butterfly pupae (monarchs, Danaus plexippus Linnaeus, and Euploea core Cramer) reared on plants to contain variable concentrations of sequestered cardenolides. We measured host survival and parasitoid reproductive success to determine whether greater concentrations of herbivore-sequestered plant toxins provide a defensive benefit or influence parasitoid success. We found that P. puparum was unable to develop from monarchs, regardless of toxicity. Monarchs containing more cardenolides (those fed Asclepias curassavica) were more likely to survive encounters with P. cassotis than those containing fewer cardenolides (fed Asclepias incarnata), but only because this parasitoid was less likely to attack more toxic monarchs. Once attacked, host toxicity had no effect on the likelihood of monarch survival nor the emergence of parasitoids. Host toxicity affected parasitoid performance in more subtle ways, however, decreasing P. cassotis brood size and survival to adulthood. When attacking cardenolide-free E. core pupae, P. cassotis reproduced successfully, but P. puparum did not, suggesting that milkweed butterflies may employ other defenses against parasitoids, perhaps in addition to cardenolides