Some Don’t Want to Blend In

The regal forms of butterflies and moths are often some of the most memorable visitors to a landscape. Although they tend to look quite different, both belong to the same order of insects, Lepidoptera. 

The over 175,000 members of this order rely on microscopic scales, many the size of a single cell, to change the appearance of their wings in order to suit their preferences. Depending on the species, these scales can distort sunlight or harbor specific pigments in order to change how the creature looks. Each scale can easily detach, allowing butterflies and moths the ability to quickly slip away from any predators grabbing on. Wing coloration in butterflies is believed to be influenced by their experiences in their younger caterpillar forms. 

For example, the color saturation in monarch butterfly wings appears to have a strong correlation with the diversity of food in the area. The more abundant their food sources as a caterpillar, the more vibrant their wings as adults. Recent studies have also discovered that in some butterflies, areas of scales are halted in their development and are turned into tiny pockets for storing specific chemicals. These caches are then thought to be used to help lure a mate, however their true purpose remains a mystery.

Butterflies tend to be noticed more because of their daylight working hours, however there are actually around eight times as many species of moths than there are butterflies. While a few moths are active during the day, most prefer the night life and rely on camouflage to keep them hidden when it’s bright out. Once the sun goes down, moths become some of our most important pollinators. In order to locate a compatible mate in the dark, most moths use pheromones, or chemical scents. Male moths are able to detect the appropriate pheromones from up to a mile away. They are so effectively drawn to their favorite pheromones that some species of spiders mimic their scents to help lure in a free meal. It seems that some of these pheromones actually give off tiny amounts of infrared light as well. This could be a reason that moths are drawn to artificial light, especially mercury vapor streetlights, which are believed to emit especially tantalizing ultraviolet wavelengths.

Butterflies are clearly not as concerned about blending in as moths are, and many species have developed wing colorations that help them visually stand apart from the plants and animals around them. They can be so bold in large part due to their ability to incorporate defensive chemicals from the plants around them into their own bodies in order to make themselves unpalatable or downright poisonous. The monarch is a classic example. It uses latex found in the milkweed it feeds on as a caterpillar to protect itself from predators. For this reason, most butterflies and moths have specific plants they use to raise their young. Plant a wide variety of plants native to the area in order to cater to the widest variety of butterflies and moths. Not every Lepidopteran is an herbivore—in fact, we even have an example here in the eastern states. Known as the harvester butterfly, its caterpillars reject the leaves of plants around them as tasteless and without challenge. Looking for a more attractive meal, they decided that woolly aphids looked appetizing and began to pursue a predatory diet as juveniles. They even cover themselves with the bodies of their prey in order to escape the attention of other predators or curious ants. 

Butterflies and moths famously practice another insect super power—complete metamorphosis. As they mature from caterpillars to adults, they manufacture a protective chrysalis to shield themselves. Once inside, it seems they release an enzyme aimed at dissolving their juvenile form into a nutrient-rich slurry. Pre-ordained groups of cells are able to survive the meltdown and use the goo around them to multiply and develop into their adult form. Interestingly, their brain also survives to the extent that butterflies can remember information learned as a caterpillar. Try not to give your local butterflies PTSD by leaving any caterpillars you find alone to mature at their leisure.

Many Have Seen A Sharp Decrease in Number of Butterflies, Moths

Despite an early flush of activity in the spring, it seems to be a bad year for butterflies, moths and other pollinators. Scientists and gardeners alike have noticed a sharp decrease in butterfly and moth numbers this summer. This is most likely due to a combination of a wet, mild winter and an especially late freeze that probably caught a good deal of insects unprepared. Luckily, butterflies and moths have developed strategies to make it through such difficult years. In particularly rough seasons, the life cycles of your local insects might become delayed in an attempt to wait out inclement conditions. It is not uncommon to see butterfly, moth, and other pollinator populations experience a significant increase in the late summer and fall during such years. This is yet another reason to plant a variety of native plants, with a variety of bloom times, in your yard. By having something in bloom throughout the season, you can rest assured that the space will provide food and shelter to butterflies and moths during any growing seasons. Remember to tolerate caterpillars on your plants, and help your local moths by leaving any unnecessary outdoor lights off whenever possible.