The erebid moth Ascalapha odorata, commonly known as the black witch, is a large, bat-shaped, dark-colored nocturnal moth, normally ranging from the southern United States to Brazil. It is also migratory into Canada and most states of the United States. The black witch is the largest noctuoid in the continental United States.
Physical Characteristics
Female moths can attain a wingspan of 24 cm. The dorsal surfaces of their wings are mottled brown with hints of iridescent purple and pink, and, in females, crossed by a white bar. The diagnostic marking is a small spot on each forewing shaped like a number nine or a comma. This spot is often green with orange highlights. Males are somewhat smaller, reaching 12 cm in width, darker in color and lacking the white bar crossing the wings. The male Black Witch Moth has superficial resemblance to a small bat. Its wings are broad along insect's head and body; pointed at the ends; often tattered by rigors of migratory flight.
Distribution and Habitat
These moths are prolific throughout the Southern United States, Mexico, Central America and into Brazil. The black witch flies north during late spring and summer. Ascalapha odorata is also encountered in the Caribbean. The moths are found in a wide variety of landscapes, although they appear to be the most common in tropical forests and tropical shrublands. That being said, the moths are able to fly long distances with ease - and thus they can show up in suburbs and parks too in some occasions. In fact, they are so skilled at flying long distances that the moths have been recorded up to New York and Canada - places where the climate is wholly unsuitable for this tropical insect (except in warm summer months!). They seem to need at least tropical to subtropical climates (reproduction does occur in places such as Florida, etc).
Black Witch Moth sightings depend on your location. In their natural habitat of Central America, South Florida, South Texas, the Caribbean, and parts of South America, Black Witch Moths are very common. In their migratory areas, Black Witch Moths are rarer although still not uncommon. Most areas of the United States and even Canada are hospitable for Black Witch Moths. Sightings are rare enough in these parts, however, to make most people take notice.
Feeding Habits
Larval Diet
The host plants for the larvae of Black Witch moths are often Acacia, Whistling Thorn, Thorntree and Wattle Trees, and the young Black Witch moths feed off of the leaves of these trees throughout the time before they undergo metamorphosis. Black Witch Moth caterpillars like to eat legumes, acacia, mesquite, and Kentucky coffee. Due to their large size, these little guys have to eat quite a bit to grow into the 3-inch caterpillars and later the 6-7 inch moths. While not a big problem for many farmers, they can be a nuisance for those that cultivate acacia and mesquite especially. They eat the leaves, however, and only use the wood for shelter.
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The larva of Ascaphala odorata is a little bit of an enigma. First of all, they are rarely observed in the wild, despite the adult moths being very common. This is due to the fact that the larvae are exclusively nocturnal! During the day, the larvae often descend from the vegetation, down to ground level, only to hide in leaf litter, or even under rocks near the host plant! In some occasions, they choose to stay high in the trees, pressing themselves tightly against the tree bark (their camouflage is amazing!). They avoid light completely, and often crawl inside cracks or crevices in order to hide.
At night, the larvae crawl up to the crown of the trees, or the tip of the branches of the shrubs or vegetation, to feed on the younger leaf shoots. Mature larvae can feed on mature foliage, but still strongly prefer young leaves. Young larvae however, seem to exclusively(!) feed on soft, young parts of the plants; including flower buds, leaf buds or young shoots. They are even able to hide inside flower buds while consuming the flower from the inside. This makes laboratory breeding difficult; the young larvae reject even their best food plants in captivity if no young leaves are available.
In the wild, the larvae mainly feed on Fabaceae. This includes Caesalpinia, Robinia, Inga, Albizia, Gymnocladus, Senna, Acacia, Pithecellobium, Uncaria, Ebenopsis, and more! Their most important food plants appear to be Acacia, Albizia and Gymnocladus; although this is a generalisation, due to them using different local host plants throughout their vast range distribution. Some reports mention the larvae can feed on non-Fabaceae such as on Ficus, Diospyros and Mangifera indica but I have not personally verified this.
Yes, that’s right! The first instars seem to more or less EXCLUSIVELY feed on young leaves, and would starve if given mature leaves; even if it is from their preferred host plants(!). This was certainly the case with Inga and Albizia, the host plants used in this article - L1 to L3 at least appear to be obligate young shoots/leaf bud feeders on these host plants; and perhaps on many other host plants too!
Adult Diet
Adults feed on overripe rainforest fruit, especially bananas, and larvae consume the leaves of plants. Like almost all moths, the adult Black Witch flies mostly at night, attracted to the nectar of flowers, the juices of fallen fruit or the sap of a legume. Ascalapha odorata is very much a frugivore. They are specifically attracted to decaying, fermenting fruit. In its natural habitat, the moth is easy to observe by putting out rotting bananas (they seem to be very fond of banana in particular) and checking them at midnight with a flashlight. Other sugar rich, fermenting fruits should also work. Attracted by the volatile alcohol, they use their long proboscis to imbibe the sugary fruit juices. This nocturnal moth (most moths are nocturnal) forages for nectar, legumes, leaves and the juice of fallen fruit.
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Life Cycle
Like all butterflies and moths - which belong to the advanced insects - the Black Witch has a ‘complete’ life cycle. Their life cycle starts with the adults mating. Then the female lays eggs. Caterpillars hatch from the eggs, feed voraciously, and spin cocoons. The Black Witch favors stands of woody legumes. The larvae, or caterpillars - striped and 2 1/2 to 3 inches in length - feed on the foliage of the legumes during the night and take refuge beneath bark during the day.
The eggs of Ascalapha odorata are incredibly small (about 2mm) - round, and grey. They hatch incredibly fast; in hot weather of 25C+ we can expect to see babies in just about 4-5 days time! They are best incubated in petri dishes and kept humid. The L1 hatchlings run incredibly fast, like Geometridae.
The first instars grow very rapidly - and if fed well, they will molt until the second instar (L2). In the third instar (L3) the larvae become more colorful. They also gain all their prolegs! Their color is hard to describe for this instar is highly variable. Larvae tend to have creamy, sand colored lines that run along their flank, and a grey base color with variable yellowish patches. From L3 and beyond, the larvae become more able to eat mature leaves from the host plants instead of young shoots. However, it depends on the host plant - the group reared on Inga exclusively fed on young shoots until pupation, refusing to touch older leaves. The Albizia feeding group became able to feed on more mature leaf after L3.
In L4, the caterpillars become less hairy. The 4th instar (L4) seems to strongly resemble the 5th instar (L5). The main difference is that L4 is smaller and less dark . In all life stages, the larvae are solitary. In fact; they seem to hate the presence of other larvae (do not overcrowd). They also avoid light, and most of their feeding activity happens at night in the darkness. Touching them makes them twitch, or regurgitate their gut contents. During the day, larvae burrow in leaf litter, or hide between the leaves. Fully grown larvae grow up to 10cm although they tend to be smaller in captivity than in the wild. Nearly fully grown A.
Ascalapha odorata are capable of spinning ‘cocoons’; however the cocoons are extremely minimalistic, and consist of dead leaves and soil being strung together with a few strings of silk (similar to Catocala). In some cases, larvae will not produce silk at all and burrow in (leaf) litter or soil to pupate. The pupae of A. odorata hatch in 3.5 to 5 weeks time it appears (the warmer, the faster). They can be kept in a layer of leaf litter, but also in humid vermiculite. Important is that they are kept moist, to prevent them from drying out!
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In captivity, the moth thrive only in large enclosures - such as greenhouses or butterfly houses. It is also possible to breed then indoors, if one dedicates a whole room to the adults - or a space of at least 3 by 2 metres (and preferably 2 metres tall). When provided rotting fruit, especially bananas, the imagoes will feed themselves - they are highly attracted to overripe bananas. If fruit can not be provided, the moths can also feed on sugar water in captivity. Mix 50% sugar and 50% water - make sure to stir - and dip the proboscis of the moths in a bottle cap, or the lid of a jar filled with the liquid. If sufficiently hungry the moths will begin to drink.
Folklore and Cultural Significance
The black witch is considered a harbinger of death in Mexican and Caribbean folklore. If you see a large, brown Black Witch Moth fly into your home, beware. Not because it is dangerous. In fact, this harmless moth is common in many areas of Central America and migrates through the United States and even Canada. However, these moths are considered to be a harbinger of death or bad luck in many folklore traditions from these areas. In many cultures, one of these moths flying into the house is considered bad luck: e.g., in Mexico, when there is sickness in a house and this moth enters, it is believed the sick person will die, though a variation on this theme (in the lower Rio Grande Valley, Texas) is that death only occurs if the moth flies in and visits all four corners of one's house (in Mesoamerica, from the pre-Hispanic era until the present time, moths have been associated with death and the number four). In Jamaica, under the name duppy bat, the black witch is seen as the embodiment of a lost soul or a soul not at rest. In Brazil it is called "mariposa-bruxa", "mariposa-negra", "bruxa-negra", and "bruxa", and it is also believed that when a moth of this type enters the house it can bring some "bad omen", signaling the death of a resident. In the Ecuadorian highlands they are called Tandacuchi and in Peru Taparacuy or Taparaco. In Hawaii, black witch mythology, though associated with death, has a happier note in that if a loved one has just died, the moth is an embodiment of the person's soul returning to say goodbye.
The nocturnal black witch moth - the largest moth in the continental United States, with a wing span of six to seven inches - has been vested with a foreboding aura of darkness and mystery. According to folklore, if the black witch flies into your field of view, it conveys a curse from an enemy. If it flies over your head, it will cause your hair to fall out. If it flies into your home when you are sick, you will not get well. On a happier note, if the black witch appears before you after someone has died, it represents the soul of the person returning to bid you farewell.
In Costa Rica and Mexico the Black Witch is called, “mariposa de la muerte,” which would translate as, “the butterfly of death.” The Black Witch is also associated with death in a number of traditions throughout the regions it inhabits. Some cultures in Latin America associate these moths with bad luck, illness, disease, witchcraft/black magic or death. Hawaiian tradition says that the Black Witch Moth is actually the spirit of a recently deceased person saying their final goodbyes. If someone that you know has died recently, a Black Witch flying into your home can be quite comforting. Some cultures believe that a Black Witch Moth landing on you means that you will experience financial good fortune soon.
Black Witch Moths and Humans
If you do want to get rid of these moths, the best thing to do is remove or relocate their preferred food source. Similar to constructing a butterfly garden or pollinator garden to attract butterflies or bees, you can make a moth garden to bring Black Witch Moths to a better spot. Common insecticides also work, although we don’t recommend going that route for Black Witch Moths.
Remember that like all moths, Black Witch Moths are nocturnal. This means that they are active at night. If you try to look for them during the day, they will not be as active and easy to spot.