Beautiful, widespread and well-known. Every autumn, Monarchs head south in one of the world’s most spectacular migrations. These butterflies are famous for this flight southward each fall. Thousands and tens of thousands of Monarchs make this journey.
Their migration route is over 2,000 miles long. Nearly all of the butterflies head to 12 mountaintops in central Mexico. These known wintering sites are within a 73-square mile area. The mountaintops have a particular kind of fir tree forest, known as an “oyamel” forest. It is in these fir trees that the Monarchs roost together by the millions. They live off their fat deposits and wait out the five months of winter.
I am not sure that anyone completely understands why the Monarchs make this migration. Somehow, the behavior evolved, and it works for the species. This year’s migrating Monarchs arrived in Mexico on Nov. 15th, a bit later than usual. A map of the sightings showed that many of the butterflies flew across Texas, but most of them were following the coast. I didn’t see a single one in Bee County this fall.
However, I have been seeing a lot of orange-and-black butterflies lately. Haven’t you?
These are Queens. The Queen butterfly is a close cousin of the Monarch. A Queen is smaller and a little bit browner (more chestnut than burnt orange) and with fewer black lines on the wings.
The Queen is a South Texas butterfly. Although Monarchs can migrate through our area, it is the Queens that are residents. Some guides say the Queens don’t migrate. But they do seem to move around a lot.
Queen butterflies are quite common in late fall. They are fond of the nectar produced by several late-season blooming plants known as the mist-flowers. The mist-flower that is native to the Coastal Bend is Crucita (Chromolaena odorata). It is also known as Fragrant Mistflower, but the fragrance appears to be more of an odor associated with the crushed leaves.
Mist-flowers are extremely attractive to Queen butterflies. So much so that scientists wondered why. In several studies done with Queens, amazing things were discovered. More male Queens than females visit the mist-flowers. As they take in the nectar, the male butterflies also ingest certain toxic chemicals, known as pyrrolizidine alkaloids, produced by the plants. The insects convert these alkaloids into male sex pheromones. Pheromones are volatile and waft in the breeze. Their smell is irresistible to female butterflies.
The pheromones are released from special pouches on the hindwings and from “hair pencils” on the butterfly’s abdomen. Hair pencils are extendable organs that project outward and release not only pheromones but bits of cuticle dust coated with the attractants.
Pheromones are essential to getting a female Queen to mate. In his courtship flight, the male Queen hovers above the female and everts his hair pencil organs. The hair pencils douse the female with pheromone-laden “love dust,” which induces her to be receptive to the male’s attentions.
In addition, during the mating, the male transfers some of the alkaloids derived from the nectar. The female butterfly’s eggs take up these chemicals. The chemicals render the eggs and newly hatched larvae bitter and noxious to the taste. This protects the juvenile butterflies from predators that would normally eat them.
You probably know that Monarch caterpillars feed on milkweed. Queen caterpillars do too. There are toxins in milkweeds that are concentrated in the larvae’s bodies and ultimately in the adult butterflies. Adult Queens and Monarchs taste bad to birds and other predators. Predators soon learn to avoid Queens, Monarchs and any other butterfly that looks like them. Thus, the adults are chemically protected against predators.
However, the eggs don’t have the bad taste unless, somehow, they are “inoculated” with the chemicals before hatching. The male Queen with his “gift” of the mist-flower alkaloids would provide even the youngest of Queens some chemical protection.
When I stop by the Crucita bush by my front gate, I can’t help but ponder the intricacy of all these interrelationships. Crucita makes special alkaloids probably to attract pollinators (and maybe keep its seeds from being eaten). These chemicals are in the nectar produced to attract butterflies. Male butterflies eat the nectar and grow strong…and sexy. Females are attracted to these males, and their babies are better protected. The juveniles grow up and pollinate more Crucita. It seems that, in this case at least, everybody wins! Well, except for hungry predators.