Monarch butterfly and milkweed relationship questions

Monarchs and Milkweed – The Precarious Cycle | My Altona Forest

monarch butterfly and milkweed relationship questions

Monarch butterflies are still fluttering through our gardens, along our roadways, Is the relationship between monarch and milkweed mutually beneficial Aquinas High School, welcomes your ideas for future column topics. Roy Lukes on the fascinating relationship between the Monarch Butterfly and the Milkweed plant. Saving Monarch Butterflies – Open Letter to the Ontario Government relationship between the native milkweed plants and the monarch.

Furthermore, Robertson et al. Because most milkweeds native to the Midwest, especially those with narrow ranges, have not been tested, we examined larval survival on nine milkweed species native to Iowa, which is a high priority area for Midwestern conservation efforts The Center for Biological Diversity The species we examined were: These species have overlapping ranges Woodsonvarying concentrations of cardenolides WoodsonRoeske et al.

We examined larval performance and survival on young plants of the nine species listed earlier to determine any differences in the resulting adults including mass, forewing length, and hindwing length, or development time days in the larval and pupal stages relative to the milkweed species on which the larvae fed.

Our prior work suggested that there were differences in both mass and lipid content in young larvae, second and third instars, that fed on both leaves and young plants of different milkweed species Pocius et al. We suspected that these differences could change as the monarch larvae develop to adulthood because there were no significant differences in pupal weight and development time among larvae that fed on A.

Understanding how milkweed species influence monarch development and survival will be critical in choosing milkweed species for monarch habitat restoration, and given the large number of acres that are being planted, this knowledge could also have significant economic implications.

Larvae were reared on A. Upon eclosion, adults were tested for Ophryocystis elektroscirrha OE. Adults that tested negative for OE were allowed to mate and eggs were collected for propagation of the colony on a weekly basis. Twelve generations of colony breeding preceded the beginning of this experiment; inbreeding should not affect monarch preferences as colony breeding for multiple generations did not influence monarch growth or performance on different milkweeds Ladner and Altizer Milkweed Feeding Assay Milkweeds of all nine species were grown from seed without the use of chemical pesticides in a greenhouse Growing conditions represent a middle ground among the nine species tested.

Seeds were sown into cell plug trays Landmark Plastics, Akron, OH and then at approximately 6 wk following germination were transplanted into 8.

Habitat Needs

Plants ranged from 10 to 30 cm in height depending on milkweed species. Milkweeds were 8 wk old when used in each trial; all plants were healthy with undamaged leaves at the start of each trial. Each plant was watered and placed into a water-filled, waxed paper cup. One neonate was added to each plant.

The experiment was arranged in a randomized complete block design with the block including one plant of each of the nine milkweed species growing in each pop up cage.

monarch butterfly and milkweed relationship questions

Each trial six blocks was replicated six times for a total of 36 blocks. All blocks were kept on the same bench in the greenhouse Larvae were monitored for survivorship on Days 5, 10, and 14, when the larvae ranged from second to fifth instar.

monarch butterfly and milkweed relationship questions

Beginning at Day 10, we monitored each cage for pupae in order to record the most accurate pupation date; we did not monitor young larvae daily in order to reduce stress on the larvae and young milkweed plants. Milkweed plants were watered daily, and additional milkweed plants were added on Days 6 and 10 to provide adequate food for each larva.

No larvae ran out of food over the course of this experiment. Larvae were monitored daily for pupation starting at Day Following pupation, chrysalids were allowed to sclerotize in the greenhouse for 24 h after which they were removed from each cage and transported to the laboratory.

Upon eclosion, adult emergence date and sex were recorded.

monarch butterfly and milkweed relationship questions

Live adults were weighed to the nearest hundredth of a milligram after allowing their wings to harden for 24 h. Adult forewing length and hindwing length were measured to the nearest hundredth of a millimeter using digital calipers Neiko Tools ; adults were then frozen for subsequent lipid extraction.

Data are presented both as average milligrams of lipid and lipid as a percentage of butterfly mass for butterflies that fed on each milkweed species. Statistical Analysis Data were analyzed using R version 3. Within each experiment, data were combined across trials 36 blocks totalas blocks were not significantly different from one another. Differences in survival were determined using a log rank test on the Kaplan—Meier survival estimates for larvae that fed on each milkweed species.

Pairwise log-rank tests were used to compare species Jokela et al. A one-way ANOVA was used to assess differences in pupal and adult responses mass, pupal length, pupal width, forewing length, and hindwing length among milkweed species. A Tukey HSD test was used to assess pairwise differences in larval development time among milkweed species.

A one-way ANOVA was used to assess differences in total percent of lipids between groups relative to the milkweed species they were fed. Still these few small areas of central Mexico are the only places they travel to.

monarch butterfly and milkweed relationship questions

When you see a monarch arrive in your garden, stop and realize that it has taken generations to get here. They slowly began to make their way across the US and stopped to have another generation.

If all goes well, the second or third generation will make it to your back yard. Many starve if they cannot find sufficient wildflower nectar in farmlands to sustain them, and rainstorms, windstorms, and pesticides are often fatal to them. There is a symbiotic relationship between the native milkweed plants and the monarch. The monarch butterflies enjoy the nectar from the flowers and help pollinate the plants.

Monarch Butterfly Habitat Needs

Unfortunately, there are no substitutes for where monarchs can lay their eggs. Swamp milkweed in Altona Forest damp growing conditions Monarch on common milkweed dry growing conditions Milkweed is a broad-leafed native plant that is used by monarchs as their only nursery.


Monarchs lay eggs on the undersides of the leaves and their larvae become striped caterpillars and feed on the leaves as they develop. Without the milkweed, the caterpillars would die — but Ontario put milkweed on the noxious weeds list which forced its eradication. The monarch caterpillars are not affected by the mildly toxic nature of this plant and become toxic themselves which makes them less attractive prey creating their defense mechanism. Monarchs feed and breed in Ontario summers.

  • Roy Lukes: The Fascinating Relationship Between Monarch Butterflies and Milkweed Plants

Come colder weather, they make that astounding migration south. The south-traveling generation are by far the longest-lived of the 4 generations.