The sphinx moth worm is black and yellow and is commonly called the “catalpa sphinx,” or “catawba worm.” The sphinx moth worm is the larvae or caterpillar stage that is most likely to be spotted rather than the moth. The larva is so bright in color, it’s tough to miss, whereas the sphinx moth is dull and gray in color.
The sphinx moth occurs in most southern states and throughout the eastern part of the United States. So if you live in any southern state or anywhere from Florida to New York and west to Iowa, Michigan, Kansas and Texas, chances are you have come in contact with the bright yellow creature.
The sphinx moth worm feeds on Catalpa trees. Its appetite is so big, that this tiny animal can strip an entire tree of its leaves. This can be a serious problem for Catalpa trees that provide shade or nursery stock, as well as Catalpa trees that are popular for their ornamental beauty. The sphinx moth worm does not feed on any other tree outside of the Catalpa tree, so these trees are vulnerable to attack at all times. The larvae are currently considered a threat to the survival of the Catalpa tree. Catalpa trees grow in all of the states mentioned above as well as in central and south central states such as Illinois and Indiana, and south to Arkansas and Tennessee.
The four life stages of the sphinx moth worm include the egg, larva, pupa, and adult. The larva is white to pale yellow and it has a black spine and a horn on its rear. When the larva begins to develop, the colors change slightly. The head turns completely black and the body remains pale yellow in color but black markings develop all over the body. The pupa is reddish brown, and the moth, as mentioned earlier, is gray.
Because the Catalpa tree has such great value and it is known for its shading capabilities and its status as an ornamental tree, many people consider the sphinx moth worm to be destructive with no real value to the environment. Because of this, pesticides are commonly used to control sphinx moth worm infestations. In addition to human threats, the sphinx moth worm is constantly under attack by the wasp. The wasp is actually a parasite that deposits its eggs through the skin of the sphinx moth worm. The wasp larvae actually feed on the insides of the sphinx moth worm, and when the wasps are ready to leave the host, they spin silken cocoons on the sphinx moth worm’s skin. An infected sphinx moth worm will not survive into adulthood if attacked by a wasp.
While many would say the sphinx moth worm is a pest, most fishermen would disagree. Sphinx moth worms are extremely popular for fish bait.
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