Monarch Butterflies

Surely we have all seen one of these incredible and beautiful insects! They are the monarch butterflies, a family of insects scientifically called danaus plexippus, with characteristics that make them stand out from the rest in terms of shape, size and color.

Monarch butterflies are known almost worldwide due to their intense and incredible migration during the winter periods to North and Central American countries such as Canada and Mexico. They are also considered by many experts in the area as one of the most evolved insects, with a greater capacity to adapt and survive in the climatic situations where they are located.

Monarch butterflies

Next, in this article we will detail each one of the characteristics that make them unique among other butterflies; likewise we will provide answers to questions such as: which are the similar species? and which are the natural predators and parasites of these butterflies?

🧐Morphological Characteristics

Size of Monarch Butterflies

The size of the Monarch Butterfly is approximately 9 to 10 centimeters.  They weigh up to 75 milligrams approximately. Very light!  It has in common with other insects to have in its head two and types of eyes, those tiny ones located in the antennas and the biggest ones, formed by many units called omatidias.  A curious fact is that at the level of the entire body and primarily on the antennas is the sense of touch of the butterflies. Male monarch butterflies are much larger than females, have thinner veins and two black circles on each rear wing. They release pheromones to attract female butterflies. In contrast, females are thinner and have thicker veins.

Monarch Butterfly Body

  • Chest. In this or at the beginning of the abdomen they have the tympanic sensory organ, which allows them to detect any noise or vibration, as a warning signal of possible enemies or companions of their own species.
  • Wings. They are made of scales that are usually small, with different shape and size. The functionality of these, is to reinforce the structure of the wing to provide greater strength and resistance in flight.

Color of Monarch Butterflies

Monarch Butterflies are easy to identify due to the very particular orange color of the wings, which are shiny and in which black veins with white spots are reflected.  The coloring adopted by the scales is due to pigmentation processes through their dietary content; or by a mechanism where light is refracted on the surface, generating aspects and colors with metallic tones.  The characteristic color of the wings is also due to a defense mechanism. For the natural predators of these insects, the color warns them that they may be poisonous or potentially dangerous.

Monarch butterflies feed on a plant whose sap is supremely toxic; so yes, they are poisonous and generate bad taste in the mouths of predators.  The lower part of the wings are usually lighter, because this allows them to camouflage on the bark of trees or on rocks.

🌎 Monarch Butterfly Life Cycle

Monarch butterflies have four stages within their life cycle: egg, caterpillar, chrysalis and adult. Their main areas of reproduction are in open places, fields where grass is cultivated, among others. Basically, they predominate where cotton plants grow for the development of the larval or caterpillar form.  In order for the life cycle to take place properly, the climatic conditions in which the areas where the eggs are to be deposited for reproduction are very influential. In climates of extremely high temperatures they are not able to resist. 

Egg

It first starts as an egg measuring about 1 mm in diameter, which is lodged on the above mentioned cotton balls, also known as asclepias and lasts about 4 to 8 days to hatch.

Monarch Butterfly Larva

The eggs then hatch to give a larva or worm, which will begin to feed on the other eggs laid, as well as the plant where the female lays the eggs. As the larva feeds, it grows into a large, robust caterpillar, which already has the characteristic orange and black pattern. It should be noted that to reach pupa, the larva passes through 5 periods that last approximately 15 days.

Monarch Butterfly Chrysalis

After the larval period, a pupa is formed ready for metamorphosis. This stage usually lasts about ten days.

Adult Monarch Butterflies

It is also named after imago, which is ready to take off with its peculiar colors. It generally lasts from two to six weeks, depending on the conditions of the ecosystem in which they are located.

🌿 Monarch Butterflies Feeding

Monarch Butterflies are herbivorous insects, initially feeding on the shells of the eggs from which they emerge and then on the leaves of the cotton plant which are toxic; these are what give them the quality of producing and maintaining the toxic in their wings. This last one is a great advantage, since besides protecting them, it gives them an unpleasant smell and flavor for their predators.

Although the Asclepias plant produces toxins that are acidic and harmful, monarch butterflies can take this poison and digest it to deposit it on all their skin; providing their body with a protective shield, which acts by diminishing the appetite of the predators that stalk them.  In the adult form of the monarch butterflies, besides the leaves they also feed on the nectar of the milkweed. Currently there is a great variety of this plant, approximately more than 120 species. And, in addition to the asclepias there are also other plants that produce nectar from which it serves as food.

🗺  Where does the monarch butterfly live?

Generally, Monarch Butterflies are not found in a single site due to their constant annual migration. As we well know, the type of habitat is terrestrial and, they can be located in the south of the American continent towards the third quarter of the year, while for the spring season they are located in the north.

monarch butterfly in flower

Monarch Butterflies are commonly found in areas with abundant grasses, open localities, gardens and less commonly in forests. In Central American countries they are located a lot towards the forests and in some cases in bushes and deserts.   The areas with higher temperatures are not the most pleasant for these butterflies.

Monarch Butterfly Migration

For monarch butterflies, migration is the process of adaptation that allows them to survive. When the time of sunlight begins to diminish and cold airs approach that drastically lower the temperature of North or Central American countries, monarch butterflies are forced to begin migrating to warmer areas; because they are not capable of regulating their internal temperature, coupled with the lack of food for the duration of the winter that causes slowing in the cotton plants, the main source of food for the butterflies.

All this allowed this species to develop physiological and morphological characteristics to resist and be able to fly long distances for a long time. They are considered the best in their adaptation and survival mechanisms.   The monarch butterflies begin the migratory process first towards the south, to take advantage of the air currents that are generated and thus plant their eggs and replicate the reproductive process.  At the beginning they arrive to the wooded areas of Mexico for the months of August to October and they stay here for five months. They group in colonies and locate healthy and mature trees with very humid canes to protect themselves from the strong climatic changes that are coming.  For the months of December to January, the objective is mainly survival.

They can be seen during these seasons, flying over the branches or in the middle part of the trees, since the wind currents are not so strong in this area, and the temperatures do not reach the extreme limits. They are grouped together at night and on cloudy or rainy days to generate heat between them. However, on occasions they rest excessively on the clusters of branches, which leads to the weight detaching the branch and the consequent fall of many of them, leaving them vulnerable to the cold and devastation.

🦋 Species Similar to Monarch Butterflies

Monarch butterflies are a type of insect that belongs to the family of butterflies called brush legs, scientifically called Nymphalidae.

Mariposa monarcaNowadays there are other species that are very similar to the monarch butterflies. The three main ones are described below:

Queen Butterfly

Queen Butterfly scientifically named after Danaus gilippus. Unlike monarchs, in this species the females are much larger than the males, they can reach up to 30 centimetres in diameter and more or less 8 cm long. They can weigh up to 12 grams. It is a giant variety, without a doubt. In addition, they can vary in colour, they are not always the characteristic orange colour with black veins.

Soldier Butterfly

Soldier Butterfly is scientifically named Danaus eresimus and measures approximately 0.7 cm in diameter. It has a variety of colours from brown to reddish and may or may not have white spots; the veins are much finer and slightly black. In some cases, their spots are not round but square.

Viceroy Butterfly

Viceroy butterfly known to scientists as Limenitis archippus. They have bright red wings, with a single black border on the edge of their wings. This border has a row of rounded dots. Unlike monarchs, the black lines do not represent the veins, but rather tubules that enhance the strength of their wings. These wings are bright reddish-orange, with a black stripe along the edges of the wings. The stripe has a row of white dots. Due to the composition of its wings, advances in visual technology have been developed through this species.

🐍 Natural Enemies of Monarch Butterflies

Thanks to the plant on which the monarch butterflies feed, they synthesize a poison that is used for their protection. However, even though in their evolutionary stages both caterpillars and imago already contain the poison in their bodies, there are certain predators that can feed on them, one of the main ones being birds, for example the following:

  • Tuner bag and dark back bag, which selectively feed on some parts of the monarch butterflies, basically the muscles located in the thorax and the adipose tissue of the abdominal part; therefore the skin that presents the toxic content discards it.
  • Rose-breasted Grosbeak. In this case, this bird is less selective so it feeds on the entire butterfly.
  • Field mice. Especially the varieties of mice that have black ears like the Peromyscus melanotis that maintain their habitat under the groups of these butterflies in order to wait patiently when they fall dead because of the weather conditions.
  • There are also parasitic microorganisms. The best known is a type of protozoan called by microbiologists as Ophryocystis elektroscirrha. It is widely distributed over North America and evidently affects the survival of monarch butterflies by constantly feeding on them until they are weakened and therefore die.

In conclusion, monarch butterflies are a wonder of nature, not only for their extraordinary and attractive beauty, but for each of the peculiarities that make them worthy representatives of “royalty”.