Mainland Florida Research Articles

Wetland Nightshade (Solanum tampicense): A Threat to Wetlands in the United States

Wetland nightshade (WNS) (Solanum tampicense Dunal) is a member of the family Solanaceae. In some texts, WNS has been referred to as Solanum houstonii Dunal, but this homonym of the 1807 S. houstonii Martyn is illegitimate according to the International Code for Botanical Nomenclature (Wunderlin et al. 1993). WNS is thought to have originated in southern Mexico, the West Indies, Guatemala, Belize (Gentry and Standley 1974), Cuba, and El Salvador (Standley 1924). It was first reported from mainland Florida in a marsh south of Punta Gorda, Charlotte County, in 1983 (Wunderlin et al. 1993). Since that time, it has been detected in Florida in Highlands (1985), DeSoto (1991), Lee (1995), and Glades (1996) counties. Recently, WNS was rediscovered on Garden Key in the Dry Tortugas (110 km west of Key West) where it was growing in a moist seep area within the partially ruined Small Magazine in Fort Jefferson. This species has been included in the plant list of the Dry Tortugas National Park since 1974 (Reimus and Robertson 1995).

Population and colony structure of the carpenter ant Camponotus floridanus.

The colony and population structure of the carpenter ant, Camponotus floridanus, were investigated by multilocus DNA fingerprinting using simple repeat motifs as probes [e.g. (GATA)4]. The mating frequency of 15 queens was determined by comparing the fingerprint patterns of the queen and 17-33 of her progeny workers. C. floridanus queens are most probably singly mated, i.e. this species is monandrous and monogynous (one queen per colony). C. floridanus occurs in all counties of mainland Florida and also inhabits most of the Key islands in the southern part of Florida. We tested whether the two mainland populations and the island populations are genetically isolated. Wright's FST and Nei's D-value of genetic distance were calculated from intercolonial bandsharing-coefficients. The population of C. floridanus is substructured (FST = 0.19 +/- 0.09) and the highest degree of genetic distance was found between one of the mainland populations and the island populations (D = 0.35). Our fingerprinting technique could successfully be transferred to 12 other Camponotus species and here also revealed sufficient variability to analyse the genetic structure. In three of these species (C. ligniperdus, C. herculeanus and C. gigas) we could determine the mating frequency of the queen in one or two colonies, respectively.

Reactivating after 11 years a 3 mgd seawater RO plant in Florida

On January 22, 1981 the Florida Keys Aqueduct Authority commissioned a 3 mgd seawater reverse osmosis plant on the island of Key West, Florida. At the time, this plant was an interim solution to a critical water need for the lower Florida Keys. The plant was to be used until a new pipeline from the mainland Florida peninsula could be completed. The plant continuously produced potable water from seawells for 18 months and then for the next 5 years was placed in standby with each bank (total of 6) being operated two hours per day every 2 weeks. For the last 6 years, the facility has been mothballed. It became evident last year, as a result of Hurricane Andrew, that the Florida Keys needed to have available emergency potable water should a disaster strike this area. Several options were examined; the least costly appeared to be the activation of the Key West RO plant, provided the facility could be refurbished at reasonable cost. This paper discusses the very positive results obtained when this plant was brought back on-line and quality water was produced. Also included is how the facility is now being upgraded to provide a satisfactory potable water supply in case an emergency strikes the locality.

Reproductive Performance of Female Key Deer

The reproductive performance of the endangered Key deer (Odocoileus virginianus clavium) is a potential limiting factor in its conservation. We analyzed data collected by necropsy of 142 female Key deer from 1968 through 1989 to provide a better understanding of their reproduction. A breeding season of about 6 months was longer than for more northerly herds of white-tailed deer. Productivity of Key deer was low (0.76 fetuses/F -1 yr of age at breeding) and fetal sex ratio (74% M) was high for the species. Rates of reproductive activity (% pregnant or lactating) for females at age of breeding were 4% for fawns, 58% for yearlings, 61% for ages 2-4 years, and 90% for females -5 years of age. Eight (17%) of 48 pregnant females carried twins, and the remainder carried single fetuses. We hypothesize that poor reproductive performance of female Key deer is due to a nutrient deficiency or that it evolved as an adaptation to an insular habitat. J. WILDL. MANAGE. 55(3):386-390 The endangered Key deer of the lower Florida Keys are smallest in mass of the subspecies of North American white-tailed deer (Hardin et al. 1984) and are isolated from mainland Florida by 60 km of water. Prior to protection from hunting, the population of Key deer declined to a low of 25-80 in 1951-52 (Dickson 1955). Klimstra et al. (1978), using spotlight surveys, estimated that the population increased to 300-400 in the early 1970's. The U.S. Fish and Wildlife Service (1985) reported a decline in population to 250-300 by 1984. Low reproductive output apparently contributed to the slow recovery of the Key deer population from the low of the early 1950's (Hardin 1974). Currently, development encroaching on habitat (U.S. Fish Wildl. Serv. 1985) and mortality due to collisions with automobiles result in a precarious status for the Key deer population. Nutrition, one of the most important factors affecting productivity of white-tailed deer (Verme 1967, McCullough 1979), affects both ovulation rate and the proportion of females that become pregnant (Sadleir 1987). An imbalanced ratio of calcium (Ca) : phosphorus (P) or deficiencies of cobalt (Co), iron (Fe), or copper (Cu) probably contribute to low productivity of whitetailed deer from the southeastern United States (Smith et al. 1956, Harlow 1972, Smith and Hunter 1978). The diet of Key deer may be deficient in P (Widowski 1977) or other nutrients, forcing females <4 years old (that have not reached peak mass) to concentrate energy and nutrients on body growth rather than reproduction. We analyzed long-term data collected from mortalities of female Key deer to indirectly test this hypothesis. Numerous individuals of the National Key Deer Refuge and the Cooperative Wildlife Research Laboratory at Southern Illinois University, Carbondale contributed to the collection and examination of carcasses. We thank M. L. Folk, J. W. Hardin, J. L. Roseberry, T. G. Scott, T. J. Wilmers, and A. Woolf for reviewing a draft f the manuscript. The Key Deer Refuge pr vided use of computer facilities. This project was funded by a grant from the Richard King Mellon Foundation.

Geographical Variation in Flights of the Mole Cricket, Scapteriscus spp. (Orthoptera: Gryllotalpidae)1

Scapteriscus acletus Rehn and Hebard and S. vicinus Scudder were accidentally introduced to the United States from South America, and between 1920 and 1960 they spread from northernmost to southernmost mainland Florida, a north-south distance of 600 km (= 5.7° lat.). Latitudinal variation in the life cycles of these recently established populations was studied by monitoring seasonality of flight for 1 to 3 + years at nine stations in peninsular Florida. Flights of both species generally showed a large spring peak and a small fall peak annually, with the fall peak of one year and the spring peak of the next attributable to a single generation of adults. Geographical variations in S. vicinus flights were minor, with the median cricket of both spring and fall flights captured at stations in north Florida several weeks later than in south Florida. Flights of S. acletus were likewise similar along the latitudinal gradient, except that at three stations in south Florida a summer peak of flight occurred that rivaled or exceeded the spring and fall peaks. This suggests that S. acletus has, in less than 40 years, made the transition from one to two generations per year, a latitudinal change that is rare in native eastern North American crickets.

PHOSPHOGLUCOSE ISOMERASE POLYMORPHISM AND NATURAL SELECTION IN THE SAND CRAB, EMERITA TALPOIDA.

Of the many studies of protein polymorphism in natural populations relatively few have dealt explicitly with the role of natural selection in determining allelic frequencies (Koehn, 1969; Koehn et al., 1971; Schopf and Gooch, 1971; Koehn and Mitton, 1972; Merritt, 1972; Koehn et al., 1973; Williams et al., 1973; Mitton et al., 1973; Ayala, 1974; Ayala and Gilpin, 1975; Mitton and Koehn 1975; Koehn et al., 1976). In most cases the action of selection has not been demonstrated experimentally. Rather, selection has been inferred on the basis of observational data; the correlation between changes in allelic frequencies and environmental parameters is thought to be the result of selection for enzymes having optimal activity under specific environmental conditions. Indeed, Koehn (1969), Koehn et al. (1971) and Merritt (1972) were able to demonstrate that enzymes produced by different genotypes had different optimal conditions and that allelic frequencies in the natural populations studied appeared to vary as a function of these conditions. The logic of the present study takes the following form. If, for a given species, migration among populations is extensive, if allelic frequencies at an enzyme locus vary as a function of environmental gradients, if there is little or no inbreeding and if there is differential survival among genotypes, then selection rather than mutation pressure, gene flow or stochastic processes is likely to be the principal factor determining allelic frequencies. Some or all of these suppositions are identical to those invoked in the studies cited although they were not always explicitly stated as such. This analysis is based on the allelic variation at the phosphoglucose isomerase (E.C.5.3.1.9) locus of the sand crab, Emerita talpoida (Say). This species is essentially panmictic as a result of the extensive pelagic dispersal of its larvae during the zoeal stage of its life cycle (Johnson, 1939; Rees, 1959; Barnes and Wenner, 1968; Dillery and Knapp, 1970; Efford, 1970). Megalopae, juveniles and adults are found at high densities in local aggregations in the intertidal wash zone (Efford, 1965; Barnes and Wenner, 1968). These more sedentary stages are restricted in their distribution to the quartz sand beaches of the western Atlantic Ocean (Wharton, 1942). The largest females produce as many as 5000 eggs per berrying period (Efford, 1970), carrying their eggs for about a month (Dudley and Cox, 1967), and may have five batches of eggs per year (Efford, 1970). Partial evidence suggests the species is a protandric hermaphrodite (Barnes and Wenner, 1968). The length of the larval dispersal stage is estimated by inference to be from 2.5 to 4 months (Efford, 1965, 1967, 1970; Barnes and Wenner, 1968). The longevity of the species has not been established. In North America the distribution of E. talpoida extends from southern Massachusetts to the southern tip of mainland Florida.

Environmental Impact of Lethal Yellowing Disease of Coconut Palms

Lethal Yellowing disease has been devastating Coconut, and presumably 14 other species of palms (including Palmyra and Date Palms), in mainland Florida since 1971. The urban environment has changed rapidly with the death of palm trees along streets, parks, and beaches. The disease is now present around the Caribbean Sea and presumably in West Africa.Widespread injections of oxytetracycline into both diseased and healthy palms are now being carried out in Florida in an effort to control the disease temporarily. The vector has not yet been identified. ‘Malayan Dwarf’ variety and the newly developed ‘Maypan’ hybrid are resistant to the disease and are being used to replace more susceptible varieties.The potential for environmental and economic disaster from the introduction of the disease to unaffected tropical countries, and the need for controlling its spread, are emphasized.