Date of Award

1981

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

The Tunica Hills region is located in West Feliciana Parish, Louisiana and north into Wilkinson County, Mississippi. It is characterized by hills 60-122 m above sea level that are composed of loess deposits. A mixed mesophytic forest association dominated by magnolia, holly and beech occurs here. A 3 1/2 year study was instituted to examine the butterfly and skipper species of this area. A lowland area (Polly Creek) 30.48 m in elevation and a higher area (Highlands) 97.54 m in height were intensively sampled. Previous records were compiled with the data taken during 1977-1980. Eighty-two species of butterflies and skippers were recorded. Hesperiidae comprised 34.2% of the fauna; Nymphalidae, 22%; Pieridae and Lycaenidae each 12.2%; Papiliondae, 7.3%; Satyridae, 6.1%; Heliconiidae, 2.4%; and Libytheidae, Danaidae and Megathymidae each 1.2%. Most species frequented fields (54.9%) and the forest edge (39.0%); 6.1% were found within the woods. Species occurrence showed 3 definite peaks; early April, late July and early October. Species abundance exhibited apexes during early April, late June, late August and early October. Sixty-five per cent of the species have double or triple broods. Twenty families of plants were recorded as nectar sources of adult butterflies and skippers. The Asteraceae were the most important plant family followed by Verbenaceae, Rosaceae and Fabaceae. The number of species available as nectar sources is positively related to both the number of insect species present and their relative abundance (P < 0.0005). White colored flowers were most often selected, followed by red-purple, yellow and purple-blue respectively. Butterfly and skipper species visited tubular-shaped flowers most often, dish-bowl shapes second and campanulate and infundibular shapes third. Most adult lepidopteran species were oligo- or polytrophic. Two mimicry complexes were observed. In the monarch-viceroy complex, the mimic (viceroy) is present at the same relative proportion as the model (monarch) during the April and October monarch migrations. In the pipe vine swallowtail mimicry complex, the spicebush swallowtail (mimic) predominates during the first half of the year followed by the red spotted purple (mimic) during the final half. The monthly low temperature was positively related to both species presence and relative abundance (P < 0.005). Total precipitation was negatively related to species presence (P < 0.005). Total precipitation was negatively related to species presence (P < 0.10) and abundance (P < 0.05). The number of cloudy days was negatively related to species presence (P < 0.0005) and abundance (P < 0.005). The number of nectar sources available, degree of cloud cover and wind direction at 1000 CST were the most important factors affecting daily species abundance. Most species of butterflies and skippers (45.1%) in the Tunica Hills evolved from North American stock while 37.8% are neotropical in origin, 14.6% are from eastern Asia, and 2.4% are European introductions. The members of the Asian group comprised the fauna associated with the Arcto-Tertiary Mixed Mesophytic Forest. These species survived in the Tunica Hills due to favorable climate and topography during the last glaciation. After the Wisconsin glacier receded, these species used the Tunica Hills as a path for dispersal. The similarity of portions of the Tunica Hills' butterfly and skipper fauna with that of the Ozark and Appalachian Mountains is due to both being derived from the same ancestral stocks.

Pages

144

Share

COinS