PRELIMINARY INVENTORY OF THE MOTH FAUNA OF THE FEN AND CEDAR SWAMP COMPLEXES AT PIERCE CEDAR CREEK INSTITUTE P. Gleave and J.H. Wilterding III, Department of Natural and Physical Sciences Olivet College Olivet, MI 49076 [email protected]; 269.749.7634 Introduction Biological inventories are important components of research in natural areas. They can serve as the foundation for subsequent research by providing biologists with information on the composition of communities and occurrence of plant and animal species that occur there. Additionally, increasing habitat changes and fragmentation, and the threat of global environmental change increases the importance of sound biological inventories for the continued monitoring of environmental health in these natural areas. Botanical inventories are arguably the most important type of biotic inventory. Primarily they are carried out to characterize the variety of plants in communities that are present in particular ecosystems, and they also inform future studies of the fauna species composition in the same area. Botanical inventories have already been completed for the wetland complexes at Pierce Cedar Creek Institute (PCCI) (Slaughter and Skean 2003a). Good plant diversity reflects good faunal diversity, which in turn, mirrors the health of the ecosystem. The prairie fen at PCCI is one of Michigan's rarest ecosystems. These areas are peat- covered wetlands fed by a constant flow of mineral-rich groundwater found only in glaciated parts of the Midwest. There are 85 known prairie fens in southern Michigan, totaling about 2,000 acres. Although globally speaking they are not considered to be imperiled, they are often found only in very small isolated pockets and good quality sites can be very difficult to find (MNFI 2004). PCCI carries a small botanical community that resembles, in most aspects, those of prairie fens without conspicuous prairie grass components (Slaughter and Skean 2003a). The white cedar swamp which carries the name of the Institute is likely the most unique feature at PCCI when compared to the surrounding area. Given that this habitat is a southern disjunct of a more northern habitat type (Slaughter and Skean, 2003b), it might be hypothesized to also harbor more cool loving disjunct populations of Lepidoptera more commonly found in Northern Michigan. A complete inventory of Lepidoptera in the cedar swamp might reveal the same trend as was found in plants. In light of increasing interest in global climate change, it may offer an opportunity to assess the impact of increases in mean global temperature to both the flora and fauna of this habitat in the future (which, given its location could be assumed to be sensitive in part to perturbations in climate). The purpose of this study was to document the number of moth species of the fen and cedar swamp wetlands of PCCI and to produce an annotated list of these species. Materials and Methods A partial survey of micro-lepidoptera of the Pierce Cedar Creek wetland complexes (prairie fen and cedar swamp) was carried out between March and October of 2006 and two sampling events in 2005. Ten generator nights & 19 trap nights occurred for a total of 48 individual sampling events during the duration of this study. Sampling has occurred generally once every week to ten days since May, but less frequently during March and April when species numbers and diversity were more limited and the weather was less favorable. Locations of sampling occurred at the northern edge of the cedar swamp south of Cloverdale Road and the fen area on the southeast corner of Brewster Lake. All sampling was done nocturnally and generally done seven to ten nights apart. Since moths navigate by celestial light, sampling is improved on moonless nights or those nights with low lunar illumination. Specimens were gathered using two sampling strategies: hand collecting and trapping. The use of both methods was required to successfully sample the selected areas during any given flight period. Both methods have advantages and disadvantages. With hand collecting, a 250W Honda Generator, 150W Hg light and a sheet was used. Selected specimens were picked off of the sheet with glass vials which were immediately refrigerated. This method prevents over collecting, but has shorter collection duration than trapping. The trapping method involved use of BioQuip 8W black light traps which attracted moths into a funnel that led down into a bucket where ethyl acetate was used as a dispatching agent. Sampling was completed in roughly the same area each time. The traps were set at dusk and retrieved at dawn allowing a longer sampling period than hand collecting. Specimen preparation was carried out by dispatching with ethyl acetate then pinned through the thorax, spread, dried and labeled. The trapped specimens were field pinned then prepared the same way. Mounted specimens were then stored in drawers for future study. All specimens are deposited in the Lepidoptera collection at Olivet College. ID’s are complete for eight of the taxonomic groups collected: Sphingidae, Notodontidae, Saturniidae, Arctiidae, Lasiocampidae, Apatelodidae, Lymantriidae, and Limacodidae. ID’s are nearly complete for Noctuidae (134 spp. collected), Geometridae (70 spp.) and to a lesser extent, the Pyralidae (28 spp.). These are the three largest families and comprise much of the moth fauna in Michigan. At the time of this report, a number of species remain undetermined from samples collected in 2005-2006. Specimen determinations were done based on experience (John Wilterding), previously identified material at MSU, Olivet College, and the author's collection, and from standard literature sources (Covell 1984), systematic revisions (Ferguson 1982; Lafontaine and Poole 1991; Lafontaine 1987, 1998; Neunzig 2003), and regional faunal papers (Forbes 1923, 1954; Rings et al.1992). Discussion The moth fauna of the swamp, fen and surrounding mixed vegetation areas at PCCI presently stands at 309 determined species of Lepidoptera, excluding the butterflies. The number of moth species from these two areas at PCCI are predicted to exceed 400 species, but a number of species that require further study involving dissection, or those from poorly known taxonomic groups have not been included in this report. The present discussion will focus on species found at PCCI that are uncommon throughout their range or in Michigan and those species typical of wetland complexes. With the exception of two pyralid species, our discussion of the PCCI Lepidoptera fauna will mostly be concerned with the Noctuidae family. Perhaps the most unusual record of a moth found at PCCI was a worn male specimen of Chortodes enervata found in a light trap sample taken at the end of July in the small fen complex south of Brewster Lake. If confirmed, the specimen marks the first occurrence of this unusual moth in MI. Very uncommon throughout its range, it is concentrated in Atlantic coastal wetland communities and a few scattered wet prairies in the Midwest (Metzler et al. 2005). In addition to this lone MI record, it has been recorded in high quality wet prairies in WI, IL, IN, and OH. The relative rarity of this species in collections, the lack of supporting literature, and the unique PCCI specimen before us, mean that further study is needed to confirm the resident status of this species at PCCI. Sampling in the fen should be conducted sparingly in order to not impact this potentially small population negatively. Another uncommon lepidopteran only recently described from specimens found in MI and WI, Ortholepis baloghi (Pyralidae) (Neunzig 2003), has been sampled from the fen at PCCI. Known only from a handful of populations from WI and MI, and associated with Potentilla as its host, the population at PCCI is fragile and should be carefully monitored. To the best of my knowledge, there is but a small population of its host plant on the southeastern corner of Brewster Lake, and this population should also be carefully monitored to ensure that it remains large enough to support the moth. Another pyralid, Pediasia abnaki (Figure 1), was found in small numbers in the fen complex and is associated with rich, sedgy wetlands (G. Balogh personal communication, 2006) (Pohl et al. 2005). At PCCI it was not found in numbers, six specimens in total were collected. Uncommon everywhere, but particularly in the north, is the occurrence of Macrochilo louisiana at PCCI in the swamp complex. The population at PCCI appears very large for this species that is generally poorly represented in collections north of the Deep South (Ferguson, 1982). It has been associated in Michigan with small pocket wetlands that are surrounded by forest communities. Wilterding (personal observation, 2006) had collected a specimen from a small Panicum wetland in nearby Eaton County, and this grass, common in some of the swamp habitat south of Cloverdale road, is a possible host of this insect. The related noctuids, Phalaenostola hanhami (from the fen) and Zanclognatha deceptricalis (from the swamp) are also very rare in collections (personal observation) as they are also rare in Ohio (Rings et al. 1992). These three species are so poorly known that little is known of the specific wetland type (if they are restricted at all) that offers suitable habitat for these insects. A number of Lepidoptera from PCCI are associated with cat-tails, rushes and lilies and not surprisingly, they are well represented by insects there. The Institute has all three Eastern species of Bellura (Noctuidae) (Figures 2-4), with the most notable of these, Bellura densa (Figure 2). In addition, the Institute has two of the three species of Archanara (Figures 5-6) in the East, both of which are not commonly encountered, and of chief interest to the Institute is the rare and local Archanara laeta (Figure 6), apparently associated with Sparganium (Forbes, 1954). The fen yielded other species of noctuids that are of interest, if only that they suggest a healthy and diverse fauna of Lepidoptera in the fen complex.