You can view the Riverside Park data from the last decade here. We average about 9 surveys per year, searching about 100 milkweed plants each survey.

The Center has been collecting data on larvae and eggs consistently for the last four years at all three branches. The information collected helps scientists determine population trends and distributions. The Monarch Larva Monitoring Project was developed by the University of Minnesota to collect long-term data on monarch populations and their habitat (milkweeds). Monarch Larva MonitoringĪll summer long, the Research & Community Science team, along with dedicated volunteers, have been looking on the underside of thousands of milkweed leaves for eggs and monarch instars (caterpillars) as a part of a nationwide community science project. The main overwintering locations are in the forests of central Mexico. The journey south to Mexico is by way of southern states and Texas. But, the final generation of that season, which consists of the individuals that migrate south, actually live up to 8 months. Most adult monarchs live for about a month during the summer. About 14-16 days later, the adult emerges from the chrysalis.

Once the 5 th instar is reached, the larva forms a chrysalis for the last step in its development. From there, the larva develops through a series on instars (1-5) that take about 2 weeks. Once a female adult monarch lays an egg (usually one single egg on the underside of a milkweed leaf), it takes about 4-5 days for the larva to hatch. From April to August, adults produce up to four generations. The offspring of the southern state individuals travel further north to summering grounds in more northern latitudes. Adult monarchs leave Mexico starting in March and arrive in the southern states when they find milkweed. Milkweeds ( Asclepias spp.) are essential plants in the life cycle of the monarch because eating the plant makes the larva and adults toxic (or at the very least distasteful) to certain predators. Monarchs are a part of the milkweed butterfly group ( Danaiinae). 'We delight in the beauty of the butterfly, but rarely admit the changes it has gone through to achieve that beauty.' – Maya Angelou Brief Natural History of the Monarch (Danaus plexippus)

Barbara kingsolver monarchs