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Danaus plexippus
Monarch males can be identified by their more narrowly margined wing veins and by the spots located on the upperside of the hindwing. These spots are specialized scent glands used to produce pheromones to attract females. Monarchs exhibit warning coloration known as aposematism. These highly noticeable colors warn potential predators of the Monarchs' unpalatability, their secondary defense mechanism. Monarchs are able to tolerate the toxic chemical cardenolide aglycone, which is ingested by the caterpillars from feeding on Milkweed plants. This chemical remains in the Monarch body into adulthood causing them to be poisonous if eaten. Some birds and rodents have become immune to the toxin, making the Monarchs more vulnerable to predators. Research has also shown the toxin levels in many Milkweed species has been decreasing, and many of the native milkweeds with higher toxicity levels have become threatened and endangered. Certain species of predators have learned to measure the toxins by taste and reject butterflies with high cardenolide aglycone levels, eating only the ones with low cardenolide aglycone levels.
Canada - South America. Fields, meadows, prairie remnants, urban and suburban parks, gardens, trees, and roadsides. Host Plants: Milkweeds (Asclepias).
Spotted nectaring on bearded iris.
4 Comments
Thank you so much Neil... This is one of my major areas of study, predators vs. prey and how human disturbance has played a major role in the current evolution of these interactions. Monarchs are a great example ... fragmented habitats & loss of vital host plants.
Thank you Alice!
Another great spotting Kim! I enjoyed your notes about aposematic coloration and defense mechanisms against predators. One of the main elements of my grad research was predator-prey interactions. The organism that I studied was the common musk turtle, which omits a foul-smelling secretion to possibly ward off predators. Cool stuff!
Your color is so vivid! wonderful job.