Habitat characteristics and phenology of larval Culicoides spp. (Diptera: Ceratopogonidae) from a coastal Georgia salt marsh

Larval habitats and adult emergence sites of the dominant ceratopogonid species were identified from a 14.6-ha site on Sea Island, a coastal Georgia barrier island, during a 14-mo period. Culicoides larvae (5,717) were identified from salt marsh soil samples and were compared on the basis of vegetation, elevation, pH, and soil minerals. Culicoides furens (Poey) larvae were significant for vegetation and calcium ion content and were most abundant in areas of Spartina alterniflora ( 1.2 m), at an intermediate elevation between low- and high-tide levels. Larvae of C. hollensis (Melander and Brues) were most abundant in areas of tall S. alterniflora ( 1.2 m) at elevations near the mean low-tide mark. Numbers of larval C. hollensis were significantly related to vegetation and presence of potassium ions. C. melleus (Coquillett) larvae were significant for soil pH and were found in areas of Distichlis spicata at elevations near the high-tide level. All species occurred in acidic soils (mean pH 5.6). Other ceratopogonids encountered were Dasyhelea atlantis Wirth and Williams, D. mutabilis (Coquillett) and Leptoconops linleyi Wirth and Atchley; L. Linleyi was found for the first time in Georgia. The relative seasonal abundance of the instars was compared with adult abundance. Lower larval densities of C. hollensis and C. melleus during spring and fall coincided with periods of adult abundance. Higher larval densities during winter and summer correlated with the bimodal spring-fall seasonal abundances of adult C. hollensis and C. melleus