Documenting Local Biodiversity: Genista Moth (Uresiphita reversalis)
For a few years the caterpillar in this photograph was another of my “mystery moths”. Figuring out its identity was almost by accident. The caterpillar in the photo is feeding on baptisia or false blue indigo (Baptisia australis) a plant in the bean family (Fabaceae). After I’d photographed the caterpillar I filed it away in my “Wildlife” folder but would from time to time look at and wonder “What is this?”.
One day I just typed into the Google search bar (some days it’s actually useful) “caterpillar on baptisia” and found out the caterpillar on my baptisia is the larva of Uresiphita reversalis (genista moth, broom moth, sophora moth).
I also got a flood of links to web sites warning of this dread caterpillar eating all the false blue indigo in their gardens. It didn’t matter that this insect is native from Nova Scotia to Iowa south to Texas and Florida and west to California. Nor did it matter that the moth was expanding its range on its own accord, the standard definition for “not invasive”. The thing was eating up all the false blue indigo in their gardens of native plants and something had to be done. That wild indigo dusky-wing butterfly (Erynnis baptisiae) larva also eat false blue indigo and wild lupine (Lupinus perennis) doesn’t seem to be a problem to the many authors of the various websites. The occurrence of the genista moth is variously described as an infestation, an invasion, or an outbreak, all extreme terms. I fully understand that if false blue indigo is a rare species in a particular state then there is cause for concern. However, a native insect that eats its normal food, in this case baptisia, in a planted garden can hardly be blamed. Why else would you plant a bed of native wildflowers if not to feed the native wildlife such as insects?
When I saw this caterpillar and its siblings defoliating my false blue indigo (which is a plant not native to Minnesota) I just let it do what it was doing thinking the thing was special as it was able to eat a toxic plant.
Genista moth is a small (wingspan 27 to 33 mm) triangular-shaped insect with a pointed head. The forewings are light to medium brown and marked with dark wavy or scalloped lines, occasionally broken or obscure, and two dark, round spots. Hindwings are yellow or orange with some brownish-gray shading at the upper tips. The caterpillars are yellowish to brownish-green with raised white-tipped black spots on each abdominal segment. Sparse long white hairs grow from the spots. The black head is spotted with white dots.
Uresiphita reversalis is a moth in the Super Family Pyraloidea, Family Crambidae, Subfamily Pyraustinae. There is only one species in North America north of Mexico but 32 species worldwide.
Range and Habitat
The range of genista moth has been expanding in the last three decades both north and south (see here, here, and here). Currently, it occurs from Nova Scotia south to Florida and west to California and north to Colorado, Nebraska and Iowa.
Clusters with as many as 80 cream colored eggs are laid on the host plant. Eggs hatch in about six days and the brightly colored, gregarious larva go through five instars before pupation. The larva spin loose silk webs over the host plant’s leaves and fruit pods. There may be more than one generation of larva in warm climates. Pupa that overwinter hatch the following spring.
Host plants of the genista moth are species from the Family Fabaceae (legumes) and members of closely related tribes. These include wild blue indigo (Baptisia australis,Tribe Thermopsideae), golden banner (Thermopsis rhombifolia, Tribe Thermopsideae), sophora (Sophora spp., Tribe Sophoreae), broom (Genista monspessulana, Tribe Genistaea), and lupines (Lupinus spp., Tribe Lupineae but sometimes placed in Genistaea). Besides their outward morphological similarities members of these tribes contain significant amounts of toxic quinolizidine alkaloids (Wink and Ludger 1999, Bunsupa et al. 2012). These alkaloids are stored in the bodies of the genista moth larva and confer protection from arthropod predators (Carrel 2001).
The genista moth was officially recorded from Minnesota in 2012 near the Twin Cities. The caterpillar pictured here was found on August 02, 2007 in Carlton County, Minnesota about 125 miles north of the Twin Cities. This makes it the earliest record of Uresiphita reversalis in Minnesota and probably the northernmost Minnesota location at the time. The five year difference between the two discoveries probably means the genista moth is more widespread in Minnesota. The range expansion may be related to warmer summers and winters and the presence of preferred host plants such as Baptisia australis planted in “native” gardens and perhaps other planted species including lupines (Lupinus spp.).
What to do about the genista moth?
Plant more baptisia, of course! That’s what I’ve done this year adding three new blue false indigo plants to my “prairie” garden just to feed the genista moth caterpillars. It’s a garden for wildlife, after all.
Blue False Indigo, Baptisia australis (W. J. Beal Botanical Garden, Michigan State University)
Bunsupa, S., Mami Yamazaki, M., and Saito1, K. (2012). Quinolizidine alkaloid biosynthesis: recent advances and future prospects. Frontiers in Plant Science (2012) 3:239
Carrel, J. E. (2001). Response of Predaceous Arthropods to Chemically Defended Larvae of the Pyralid Moth Uresiphita reversalis (Guenée) (Lepidoptera: Pyralidae). Journal of the Kansas Entomological Society, Volume 74(3):128-135.
Chávez-Sánchez, I. P., Mundaca, E. A., Mendez-Montiel, J. T., and Bolaños, R. C. (2014) Observations on the biology and distribution of Uresiphita reversalis (Lepidoptera, Crambidae), a defoliator of the native tree Calia secundiflora in México. Revista Brasileira de Entomologia 58(3): 305–308. (http://dx.doi.org/10.1590/S0085-56262014000300014)
False Blue Indigo (Blue Wild Indigo, False Indigo) (Friends of the Wildflower Garden, Inc.)
Genista Broom Moth (Butterflies of Orange County, California, University of California, Irvine)
Genista Broom Moths Return to Minnesota (University of Minnesota, Extension)
Leen, R. (1995). Biology of Uresiphita reversalis (Gluenee) and Comparison with U. polygonalis maorjalis (Felder) (CRAMBIDAE). Journal of the Lepidopterists’ Society. 49(2): 163-170.
Pest Alert: Genista Broom Moth (Penn State Extension)
Raczyńska, E. D, Makowski, M, Górnicka, E., and Darowska, M. (2005). Ab Initio Studies on the Preferred Site of Protonation in Cytisine in the Gas Phase and Water. International Journal of Molecular Sciences. 6: 143-156.
Species Uresiphita reversalis – Genista Broom Moth (Bug Guide)
Uresiphita reversalis – Genista Broom Moth (Mississppi Entomological Museum, Mississippi State University)
Wink, M. and Ludger, W. (1999). Storage of Quiolizidine Alkaloids in Macrosiphum albifrons and Aphis genistae (Homoptera: Aphididae). Entomologia Generalis 15(4):237-254.