Mexican bean beetle of the lady beetle family belongs to the eastern parts of the United States , alongcol3 parts of Mexico, and Canada. It is famous as an agricultural pest, one of the few exceptions of its family, which thrives on plants and insects.
Size: 8mm (0.31 inches) in length; 6mm (0.23 inches) in width
Color: When newly emerged, they have a straw-colored or yellowish-cream appearance. One of their striking color patterns is the eight black spots lying on each col3 of their elytra. As they grow, these beetles acquire orangish-brown coloration with a tinge of bronze, the black spots getting less prominent then.
Other Characteristic Features: They display sexual dimorphism, with the males being a little smaller than their female counterparts. Moreover, the former even has an indentation of the last segment of its abdomen’s ventral part, absent in the latter.
On hatching from the eggs, the larva has a light yellow coloration with spiny projections on their back. The spines appear yellow at the onset but eventually get darker, particularly near the tips, and even more prominent. The average length of a mature larva is between 6.5 and 9 mm, alongcol3 a greenish-yellow coloration.
The mature larva remains attached to the undercol3s of the bean plant’s stems, pods, or leaves to pupate. The pupa has a yellow body without any spines, closely resembling the adults in shape and size.
The eggs are yellow or orange-yellow, having and length and width of 1.3 mm and 0.6 mm. They are laid on the bean leaves’ undercol3s in clusters of 40 to 75.
| Other Names | Bean beetle |
| Adult lifespan | About two weeks |
| Duration of larval stage | Approximately one month |
| Distribution | Eastern United States (particularly in the eastern parts of the Rocky Mountains), Mexico, and certain portions of Canada |
| Habitat | In gardens, near farmlands, fields, and everywhere else where their host plants grow; particularly in well-irrigated wetlands |
| Common Predators | Birds, tachinid flies, parasitic wasps, toads, spined soldier beetles |
| Seasons active from | Not recorded |
| Host Plants | Mostly snap beans, and lima beans, alongcol3 other plants like alfalfa, soybean, clover, black-eyed pea, cowpea |
| Diet of larvae and adults | Pod tissues, flowers and leaves of their host plants |
Though both the larva and adults eat the leaves, flowers, and pod tissues, the former causes more damage than the latter. They feed on the undercol3s of the foliage, giving it a skeletonized look. Because of this, the leaves’ upper parts even get damaged. Since they even eat flowers and pods, these beetles cause immense destruction to them too.
Image Source: dh1muyqdu88ie.cloudfront.net, static.inaturalist.org, kentuckypestnews.files.wordpress.com, pnwhandbooks.org, findingharmonyblog.files.wordpress.com, reformationacres.com, bugguide.net, sciencesource.com
Mexican bean beetle of the lady beetle family belongs to the eastern parts of the United States , alongcol3 parts of Mexico, and Canada. It is famous as an agricultural pest, one of the few exceptions of its family, which thrives on plants and insects.
Size: 8mm (0.31 inches) in length; 6mm (0.23 inches) in width
Color: When newly emerged, they have a straw-colored or yellowish-cream appearance. One of their striking color patterns is the eight black spots lying on each col3 of their elytra. As they grow, these beetles acquire orangish-brown coloration with a tinge of bronze, the black spots getting less prominent then.
Other Characteristic Features: They display sexual dimorphism, with the males being a little smaller than their female counterparts. Moreover, the former even has an indentation of the last segment of its abdomen’s ventral part, absent in the latter.
On hatching from the eggs, the larva has a light yellow coloration with spiny projections on their back. The spines appear yellow at the onset but eventually get darker, particularly near the tips, and even more prominent. The average length of a mature larva is between 6.5 and 9 mm, alongcol3 a greenish-yellow coloration.
The mature larva remains attached to the undercol3s of the bean plant’s stems, pods, or leaves to pupate. The pupa has a yellow body without any spines, closely resembling the adults in shape and size.
The eggs are yellow or orange-yellow, having and length and width of 1.3 mm and 0.6 mm. They are laid on the bean leaves’ undercol3s in clusters of 40 to 75.
| Other Names | Bean beetle |
| Adult lifespan | About two weeks |
| Duration of larval stage | Approximately one month |
| Distribution | Eastern United States (particularly in the eastern parts of the Rocky Mountains), Mexico, and certain portions of Canada |
| Habitat | In gardens, near farmlands, fields, and everywhere else where their host plants grow; particularly in well-irrigated wetlands |
| Common Predators | Birds, tachinid flies, parasitic wasps, toads, spined soldier beetles |
| Seasons active from | Not recorded |
| Host Plants | Mostly snap beans, and lima beans, alongcol3 other plants like alfalfa, soybean, clover, black-eyed pea, cowpea |
| Diet of larvae and adults | Pod tissues, flowers and leaves of their host plants |
Though both the larva and adults eat the leaves, flowers, and pod tissues, the former causes more damage than the latter. They feed on the undercol3s of the foliage, giving it a skeletonized look. Because of this, the leaves’ upper parts even get damaged. Since they even eat flowers and pods, these beetles cause immense destruction to them too.
Image Source: dh1muyqdu88ie.cloudfront.net, static.inaturalist.org, kentuckypestnews.files.wordpress.com, pnwhandbooks.org, findingharmonyblog.files.wordpress.com, reformationacres.com, bugguide.net, sciencesource.com
