Zoogeographic relationships of some selected atheriniform fishes which occur in the southeastern United States and Yucatan were investigated. Analytical methods included standard meristics and morphometrics, and horizontal starch gel electrophoresis of isozymes. / No significant taxonomic differences between the various allopatric populations of Lucania parva were detected. The Yucatan population is essentially fixed for an alternative allele at only one locus, GPI-2. No evidence for dispersal between south Florida and the Yucatan peninsula was noted, although dispersal could not be ruled out. Meristic data indicate that Yucatan populations are glacial relicts that were derived from western Gulf of Mexico populations. / Florida and Yucatan populations of Floridichthys are fixed for alternative alleles at 5 genetic loci, and there is a strong difference in allele frequency at EST-4. Based on this genetic evidence, as well as on meristic differences, body size, and coloration, the Yucatan population of F. carpio polyommus is herein elevated to specific level. This study did not support Hubbs' (1936) claim of distinct subspecies within the Yucatan peninsula. Extreme differences between the Florida and Yucatan populations preclude speculation as to whether or not dispersal between the Florida and Yucatan peninsulas occurred at some time in the past, or alternatively, whether or not Floridichthys was once continuously represented around the Gulf of Mexico, with recent climatic cooling subsequently eliminating intermediate populations in the northern and western Gulf of Mexico. / Johnson's (1975) distinction between Menidia peninsulae and M. beryllina is supported. The first collections of M. conchorum outside the lower Florida Keys are reported. No electrophoretically detectable differences between this fish and M. peninsulae were found. Meristic differences display clinal variation; the counts characteristic of M. conchorum grade into southernmost populations of M. peninsulae. Consequently, these fishes are considered conspecific. Menidia colei, restricted to the northern coast of Yucatan, is most clearly related to western Gulf of Mexico populations of M. peninsulae, and is considered a glacial relict of a once continuous circum-Gulf of Mexico population which ranged into Yucatan. / Source: Dissertation Abstracts International, Volume: 41-03, Section: B, page: 0849. / Thesis (Ph.D.)--The Florida State University, 1980.

In Chapter I the habitats of the larval and adult Probopyrus pandalicola on Palaemonetes paludosus are described. The female was obliquely positioned within the shrimp branchial chamber, with its head directed posterodorsally in relation to the host, and there was no preference for the right or left host gill chamber. The tiny male usually was attached between the pleopods of the abdomen of the female parasite. However, some males attached to the gills of the shrimp, and supernumerary males were occasionally present. Larval isopods were located on the abdomen and in the brood chamber of the female parasite, and on the shrimp from the antennae posteriorly to the telson. / In Chapter II information is provided on the reproduction, parasite attachment, postlarval development and population structure of P. pandalicola on P. paludosus collected monthly for two years from a site in the Wakulla River and a tributary, McBride's Slough, Wakulla County, Florida. Ovigerous P.pandalicola occurred from January to October. Brood size ranged from 350-11,850 and increased exponentially with length of the female. Brood size was independent of host sex. As many as seven broods were produced per female. Cryptoniscus larvae occurred on shrimp 9-39 mm long from April-October. / In Chapter III the distribution of infected P. paludosus and the infection levels of P. pandalicola with respect to site, season and host size and sex are described. Infected P. paludosus occurred as far as 33 km upstream in many coastal rivers and canals throughout Florida. Free-swimming isopod larvae and the intermediate copepod host Acartia tonsa were collected in the plankton of the Wakulla River, and it appeared that cryptoniscus larvae swam at least as far as 13 km upstream to infect the definitive shrimp host after leaving the copepod. In the Wakulla River infection levels ranged from 87.5% to 100%. In contrast, at McBride's Slough infection levels fluctuated from 0.9-93.2%. In the St. Marks River the frequency of infected shrimp gradually increased from 0% upstream to 96%, 6 km further downstream. A significantly greater percentage of females than male hosts were infected, but only females of size classes less than 31 mm long had a greater frequency of infection. Female P. pandalicola were greatly underdispersed (s('2)/x < 1) throughout the host population; 99.6% of the infected hosts carried only one female parasite. / In Chapter IV the effects of P. pandalicola on the sex characters of P. paludosus are described, and possible mechanisms for these effects are discussed. P. pandalicola sterilize the female host by preventing ovarian maturation but do not affect the external sex characters. In contrast, male secondary sex characters were modified, but there was no parasitic effect on the testes. The mechanism for these castration effects appears to be some combination of a nutritional drain and/or a hormonal interference by the parasite. / The potential economic importance of crustacean castrators is detailed in Chapter V. Many hosts of crustacean castrators are of commercial value to man as a direct source of food. At least 28 species of economically valuable caridean shrimps, 10 penaeid shrimps, 3 brachyuran crabs, 2 anomuran crabs, and 4 nephropid lobsters have been recorded as hosts. / Source: Dissertation Abstracts International, Volume: 41-11, Section: B, page: 4031. / Thesis (Ph.D.)--The Florida State University, 1979.

Long term patterns of crustacean behavior are profoundly influenced by cycles of molting and reproduction. The crustacean eyestalk has neurosecretory organs that affect molting and gonadal development via inhibition. I examined how photoperiod and temperature interact to control these processes via the eyestalk endocrine system in the spiny lobster, Panulirus argus. Short photoperiod (8:16) and warm temperature (28(DEGREES)C) shortened the molt cylce when compared to long photoperiod (16:8) controls. This acceleration was due to the shortening of the transition from intermolt (stage C) to proecdysis (stage D(,o)). Short photoperiod also shortened the molt cycle compared to long photoperiod at 21(DEGREES)C. Photoperiod has an intergral role in the seasonal regulation of the lobster molt cycle. / Gonadal recrudescence does not occur in the summer and winter when lobsters are treated with either long (16:8) or short (8:16) days at either 21(DEGREES) or 28(DEGREES)C. In the spring, short days induce gonadal growth, but long days inhibit gonadal growth. Apparently, gonad recrudescence is refractory to photic or thermal stimulation in the summer and winter, but not in the spring. / Studies of several crustaceans have demonstrated that eyestalk factors affect molt and gonadal development (Kleinholz, 1976). Eyestalk ablated lobsters develop gonads larger than intact controls. Similarly, eyestalk ablated lobsters molt faster than intact controls. However, eyestalk ablated lobsters that molt have significantly smaller gonads than those eyestalk ablated lobsters that do not molt. Sinus glands implanted into eyestalk ablated lobsters slow both gonadal development and the molt cycle duration, when compared to eyestalk ablated controls. Extracts of the eyestalk injected into either eyestalk ablated P. argus or the crab, Uca pugilator inhibit the anticipated gonadal growth. / An extract of the eyestalks of P. argus was chromatographed on Sephadex G-25, then bioassayed for melanophore dispersion, molt inhibition, and gonadal inhibition in the crab, Uca pugilator. The peak of gonad inhibiting activity had an rf value equal to .45 (+OR-) .02, the peak of molt inhibiting activity had an rf value of .39 (+OR-) .02. Polyacrylamide gel electrophoresis of the Sephadex column fractions found that gonad-inhibiting-hormone, GIH, had a molecular weight near 5000 Daltons, molt-inhibiting-hormone, MIH has a molecular weight less than 3485 Daltons. GIH from lobsters can disperse the Uca melanophores, but the lobster MIH does not. The pigment-dispersing-hormone, PDH, from Uca eyestalks has the same molecular weight as the lobster GIH. PDH can also inhibit gonadal growth in the fiddler crabs. It is concluded that lobster GIH and the chromatophorotropins are related peptides, but they both are distinct from MIH. / Source: Dissertation Abstracts International, Volume: 42-10, Section: B, page: 3981. / Thesis (Ph.D.)--The Florida State University, 1981.

Source: Dissertation Abstracts International, Volume: 40-06, Section: B, page: 2557. / Thesis (Ph.D.)--The Florida State University, 1979.

Source: Dissertation Abstracts International, Volume: 32-12, Section: B, page: 7373. / Thesis (Ph.D.)--The Florida State University, 1971.

Source: Dissertation Abstracts International, Volume: 36-02, Section: B, page: 0609. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 36-02, Section: B, page: 0614. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 36-06, Section: B, page: 2661. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 36-06, Section: B, page: 2667. / Thesis (Ph.D.)--The Florida State University, 1975.

Source: Dissertation Abstracts International, Volume: 35-08, Section: B, page: 4280. / Thesis (Ph.D.)--The Florida State University, 1974.