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Fernaldella georgianaOhoopee Narraga
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G1G3
State Rank: S2S3
SWAP High Priority Species (SGCN): Yes
Element Occurrences (EOs) in Georgia: 5
Habitat Summary for element in Georgia: Woody goldenrod, sandy dune systems
Fernaldella georgiana is a small moth, with a wingspan between 2 and 2.6 cm. Females typically are larger than males. As is typical for many moths, the antennae of males are plumose (see photos), and the female antennae are simple. The upperside pattern is rather unremarkable, being uniform brown, with three yellowish patches along the costa of the forewing (see image below). The underside, however, is unmistakable. The ground color of the hindwing and the tip and outer edge of the forewing is yellow. The hindwing underside has a silvery white band through the median area of the hindwing, as well as some irregular basal silvery white patches, and the outer edge of both the forewing and hindwing has silvery-white ovals between the veins (see photos). As the moth typically sits with wings up (see photo above), the underside pattern is readily visible when the moth is resting.
There are two other species in the genus Fernaldella in the U.S. However, neither species occurs in Georgia, which means that all Fernadella in Georgia are assignable to F. georgiana. F. georgiana is most similar to F. fimetaria, which is widely distributed in the midwestern and southwestern parts of the country. It has been found as far east as western Missouri and Louisiana. F. fimetaria is noticeably smaller than F. georgiana. The other species, F. stalachtaria, is found farther west and has a lighter orange-brown ground color.
Fernaldella georgiana is a Georgia endemic. It is found in sandy/dune habitats, specifically associated with the Ohoopee Dune System along the Ohoopee/Little Ohoopee Rivers (hence the common name of the moth). It is currently known from Emanuel and Tattnall counties (as in the original description, Covell, et al., 1984), and has recently (2020) been found in sandy habitats at Alligator Creek Wildlife Management Area in Wheeler County in Georgia. The moth is found in very close association with its foodplant, Woody Goldenrod (Chrysoma pauciflosculosa).
As indicated above, the only recorded foodplant for this species is Woody Goldenrod, Chrysoma pauciflosculosa (Michx.) Greene (Asteraceae).
The adults can be found sitting on a variety of plants in the habitat for this moth, and yet I have not noticed this moth actively feeding on anything.
Adults are active during the daytime, flying from early morning to dusk, and always associated with the larval foodplants. The moths tend to be less active in the middle of very hot days. F. georgiana is easily observed by walking among the food plants, as the moth is easily disturbed from its resting perches. When flushed, the moth will fly erratically among the food plants, never flying more than about a meter and a half off the ground and always close to the food plants or along the ground. It is active at night as well, as the moth will come to lights.
The moth is trivoltine, with strong flights in early to mid April, mid to late June, and from late August into early September. There are scattered occurrences of the moth between these dates, however, suggesting that the moth may continuously emerge throughout much of the year. There are scattered records of the moth in all months from March through early October.
Eggs laid from the April generation hatched in 9 to 16 days. Those laid from the summer broods hatched in about a week (Schweitzer, et al., 2011). The larval stage lasts about a month. The mature larva is 23-24 mm in length, green, with grainy irregular yellowish-green longitudinal striations and an irregular lateral stripe described as yellowish. It is highly cryptic on leaves of the host (Covell, et al., 1984). Some of the larvae apparently burrow into the sand to pupate (Covell, et al., 1984; Ferguson, 2008), though some pupate on the surface in a light cocoon (Schweitzer, et al., 2011).
Although there are just a few known colonies, the Ohoopee Dune System is quite extensive (and remarkably visible on Google Earth), extending from the Johnson/Emanuel County line SE of Kite down to near the Altamaha River in southern Tattnall County. I have no doubt that the moth is present on many of these dunes, and for those that are accessible, they should be surveyed for presence of the moth. Although there are not records currently for Candler County, there is one large dune that appears to be the appropriate habitat off the north end of Coleman Road that should also be surveyed at some point. The fact that the moth has recently (2020) been found in Wheeler Co. at Alligator Creek WMA suggests that the moth is not completely restricted to the Ohoopee System, and so sandy habitats with abundance of the foodplant in other parts of the coastal plain of Georgia should indeed be surveyed for the presence of the moth.
As already indicated, F. georgiana is a Georgia endemic, with records from Emanuel, Tattnall, and Wheeler Counties. The known locations include some of the Natural Areas in the Ohoopee Dune system as well as other of the Ohoopee Dunes down into Tattnall County. This includes some localities where the dunes have been largely degraded, but even on these dunes the moths can thrive. There is an old record from near Baxley in Appling County, but there are no recent records from there. Because of the recent discovery of the moth in Wheeler County, F. georgiana may also be in other nearby counties at sites with an abundance of the foodplant. It should be noted that although the moth is very restricted in its range, where the moth is found, it is often a VERY common moth.
Speaking of the food plant, C. pauciflosculosa is widely distributed across the southeast coastal plain from North Carolina to Mississippi, but since F. georgiana is not found across the entire range of the food plant, there clearly must be other factors that determine the restricted nature of the range of the moth.
These sandy/dune habitats are not a high priority for development, and the fact that many of the Ohoopee Dunes show up very obviously on Google Earth suggest that a lot of them have not been developed by private landowners. The biggest threat in terms of development for these areas is residential and not industrial.
The species might be fire sensitive, but if pupation is largely underground then fire should not be a major danger to the species, especially since the habitat is often somewhat sparsely vegetated, so that there are natural fire breaks preventing sustained conflagration.
If the invasive Gypsy Moths (Lymantria dispar) make it this far south from established populations farther north, populations of Fernaldella georgiana might be susceptible to Gypsy Moth control measures, specifically the bacterium Bacillus thuringiensis kurstaki (Btk). This bacterium is dispersed onto larval L. dispar populations, typically in the Spring, and F. georgiana larvae would likely be susceptible to infection by the bacterium (Schweitzer, et al., 2011). However, Woody Goldenrod would likely not be a food plant for L. dispar, and so it seems unlikely that Btk would be applied directly to F. georgiana habitat.
The Conservation status would currently be S2, but could easily be S3 with further survey. Since this is a Georgia Endemic, this would translate to a G2G3 global status.
Some of the populations of the moth are already protected or semi-protected in the Emanuel County Ohoopee Dune Natural Areas and at the Alligator Creek WMA in Wheeler County. As a number of the other Ohoopee dunes do not appear to be developed (images on Google Earth), then, should survey of some of these dunes show presence of the moth, and financial circumstances make it possible, some more of the dunes could be purchased and protected, depending on the current ownership status of those dunes.
Covell, C. V., I. L. Finkelstein, and A. A. Towers. 1984. A new species of Narraga Walker (Geometridae, Ennominae) from Georgia, with biological notes. Journal of Research on the Lepidoptera 23(2): 161-168.
Ferguson, D. C. 2008. Geometroidea: Geometridae (Part). The moths of America north of Mexico Fascicle 18.1. E. W. Classey Limited and the Wedge Entomological Research Foundation, Washington, D.C.
Schweitzer, D. F., M. C. Minno, and D. L. Wagner. 2011. Rare, declining and poorly known butterfly and moths (Lepidoptera) of forests and woodlands in the eastern United States, pages 238-240. Forest Health Technology Enterprise Team.
James K. Adams, Professor of Biology, Dalton State College, Dalton, GA
June 27, 2020