Research
Trends In deforestation and forest degradation in Mexico have affects on Monarchs:
-
Aerial photographs, satellite images, and field surveys to monitor forest cover in the core zones of the Monarch Butterfly Biosphere Reserve in Michoacan Mexico from 2001 to 2012.
-
A total of 2179 of forest of the core zones was affected between 2001 and 2012: 1254 were deforested and 925 were degraded
-
Conclusion: the monarch butterfly (Danaus plexippus) overwintering colonies in Mexico which engage in one of the longest known insect migration are threatened by deforestation, and a multistakeholder, regional, sustainable-development strategy is needed to protect the reserve.
Fitness costs of animal medication: antiparasitic plant
chemicals reduce fitness of monarch butterfly hosts
-
When conducting the research they used mixed-effects models in which monarch lineage was included as a random factor.
-
To test whether plants pecies and parasite infection affect monarch life span, they used a mixed-effects linear model in which plant species identity, parasite treatment and their interactions were independent variables and life span (days) of individual monarchs was the dependent variable.
-
On the graph the caterpillars from a non infected milkweed had a longer life span than those who ate the infected milkweed (stripped bars)
-
conclusion: Among eight milkweed species that vary substantially in their foliar cardenolide concentration and composition, we observed the opposing effects of cardenolides on monarch fitness traits. While high foliar cardenolide concentrations increased the tolerance of monarch butter-flies to infection, they reduced the survival rate of caterpillars to adulthood.
