Hemoparasites of raccoons (Procyon lotor) in Florida

Four hemoparasite species (Babesia lotori, Trypanosoma cruzi, Dirofilaria tenuis and Mansonella llewellyni) were found in raccoons (Procyon lotor) collected from 1972 to 1974 in Duval (n = 14) and Collier (n = 170) counties, Florida (USA). Trypanosoma cruzi was found in thin blood smears from one raccoon at each locality. The prevalence of B. lotori was 79% and 80% in samples taken in December 1973 in Collier and Duval counties, respectively. No patent infections by B. lotori were detected in raccoons collected in Collier County in December 1972, but 42% of the raccoons examined in September 1973 were infected. In Collier County there were no significant differences in the prevalence of B. lotori by host sex or age. In Duval County, overall D. tenuis prevalence was 7%, whereas that of M. llewellyni was 14%; the latter species was not found in Collier County. Adult raccoons had a significantly greater prevalence of D. tenuis (32%) than did subadults and juveniles (7%), and male raccoons showed a significantly greater prevalence (51%) than did females (8%).     

Feeding on gastropods by lake-dwelling Polycelis in the absence and presence of Dugesia polychroa (Turbellaria, Tricladida)

SUMMARY. Using a serological technique, the extent of feeding upon snails by Polycelis tenuis was compared in habitats lacking and containing Dugesia polychroa which is the major triclad predator of snails. It was found that P. tenuis ate significantly more snails when D. polychroa was absent. It was concluded that in the field interspecific competition for snails between these two triclad species was a more powerful process than any social feeding by P. tenuis on snails captured by D. polychroa .
Feeding on snails as a group by P. tenuis and P. nigra in the habitat where the two triclads co-existed was of a similar magnitude and this was also true of their feeding on the common snail species and genera. Approximately 10% of the triclads gave a positive reaction to snail antisera.
Feeding on snails by P. nigra in the three habitats lacking D. polychroa was similar in extent and did not differ from that of P. tenuis . It was concluded that P. nigra would be similarly affected by the presence and absence of D. polychroa as shown for P. tenuis .
No definitive seasonal pattern was detected in the incidence of feeding upon snails by either Polycelis species but this may have been obscured by seasonal changes in the detection period of snail antigens due to temperature effects. There was some evidence that such feeding increased during the period when small snails were present in the population.     

Testing hypotheses driving genetic structure in the cooperatively breeding Brown‐headed Nuthatch Sitta pusilla

Habitat fragmentation has often been implicated in the decline of many species. For habitat specialists and/or sedentary species, loss of habitat can result in population isolation and lead to negative genetic effects. However, factors other than fragmentation can often be important and also need to be considered when assessing the genetic structure of a species. We genotyped individuals from 13 populations of the cooperatively breeding Brown‐headed Nuthatch Sitta pusilla in Florida to test three alternative hypotheses regarding the effects that habitat fragmentation might have on genetic structure. A map of potential habitat developed from recent satellite imagery suggested that Brown‐headed Nuthatch populations in southern Florida occupied smaller and more isolated habitat patches (i.e. were more fragmented) than populations in northern Florida. We also genotyped individuals from a small, isolated Brown‐headed Nuthatch population on Grand Bahama Island. We found that populations associated with more fragmented habitat in southern Florida had lower allelic richness than populations in northern Florida (P = 0.02), although there were no differences in heterozygosity. Although pairwise estimates of F_ST were low overall, values among southern populations were generally higher than northern populations. Population assignment tests identified K = 3 clusters corresponding to a northern cluster, a southern cluster and a unique population in southeast Florida; using sampling localities as prior information revealed K = 7 clusters, with greater structure only among southern Florida populations. The Bahamas population showed moderate to high differentiation compared with Florida populations. Overall, our results suggest that fragmentation could affect gene flow in Brown‐headed Nuthatch populations and is likely to become more pronounced over time.     

Ecology of helminth parasitism in bobwhites from northern Florida

Examination of 700 northern bobwhites (Colinus virginianus), 50 each February from 1971 through 1984, from Tall Timbers Research Station, Leon County, Florida, disclosed 15 species of helminth parasites. Nine species (Raillietina cesticillus, R. colinia, Aproctella stoddardi, Cheilospirura spinosa, Cyrnea colini, Dispharynx nasuta, Heterakis isolonche, Tetrameres pattersoni, and Trichostrongylus tenuis) generally were found on an annual basis and were considered characteristic components of the helminth fauna. Infrequently found species were Brachylecithum nanum, Rhabdometra odiosa, Capillaria sp., Gongylonema ingluvicola, H. gallinarum, and Oxyspirura matogrosensis. Intensities of C. colini and H. isolonche differed among host sex and age classes, and prevalences and/or intensities of A. stoddardi, C. spinosa, T. pattersoni, and T. tenuis differed between host age classes. Prevalences and/or abundances of seven species (R. cesticillus, R. colinia, C. spinosa, C. colini, H. isolonche, T. pattersoni, and T. tenuis) varied with bobwhite density, apparently because bobwhites were either the primary or only definitive host on the area. Two species (A. stoddardi and D. nasuta) did not vary with bobwhite density, apparently due to the buffering effect of a broad range of definitive hosts on the area. Prevalences and/or intensities of R. colinia, C. spinosa, and T. tenuis differed with agricultural fields status (cultivated versus fallow) suggesting that land use and its attendant habitat changes influenced transmission of these species. The occurrence of C. spinosa and T. pattersoni in individual bobwhites was not independent and was attributed to utilization of the same species of grasshoppers as intermediate hosts. Localized tissue damage and inflammation were associated with A. stoddardi, D. nasuta, C. spinosa, C. colini and T. pattersoni. Decreases in body weight in juvenile bobwhites were associated with increasing intensities of H. isolonche and T. tenuis. The observed relationships to bobwhite density and other variables are discussed with regard to known aspects of life histories of the nine most common species.     

Embryonic staging series for the beach spawning, terrestrially incubating California grunion Leuresthes tenuiswith comparisons to other Atherinomorpha

California grunion Leuresthes tenuis synchronize spawning with tidal cycles, so the embryos incubate in a terrestrial environment, delay hatching until cued by a specific environmental trigger, and may extend incubation for up to an additional four weeks. These adaptations, however, do not appear to alter the morphology or sequence of early developmental stages as compared to other Atherinomorph fishes in the Orders Beloniformes and Cyprinodontiformes. Embryonic development is described in a series of 30 stages based on morphology observed by light microscopy. Stages are placed in five periods: zygote and cleavage, blastula, gastrula, segmentation and organogenesis, and hatching competence. Embryos from a southern population of L. tenuis in Los Angeles are compared with embryos found >560 km north in San Francisco Bay. Northern L. tenuis embryos developed more slowly at several stages than southern embryos and reached hatching competence later, but both locations maintained synchrony with the tidal cycle for both spawning and hatching. The variation in rates of development and stage at hatching readiness are forms of developmental heterochrony that may be associated with evolutionary adaptation or morphological plasticity within this highly successful clade.     

Meningeal worm in free-ranging deer in Nebraska

The meningeal worm (Parelaphostrongylus tenuis) was found in 22 (7%) of 300 white-tailed deer (Odocoileus virginianus) (257 adults, 43 fawns) examined from Nebraska (USA) during November 1996. None of 53 mule deer (Odocoileus hemionus) (47 adults and 6 fawns) examined were infected. Twenty-two white-tailed deer from 18 counties in eastern Nebraska were infected with Parelaphostrongylus tenuis. This is the first record of P. tenuis in white-tailed deer from this state.     

Comparative phylogeography of woodland reptiles in California: repeated patterns of cladogenesis and population expansion

The ultimate goal of comparative phylogeographical analyses is to infer processes of diversification from contemporary geographical patterns of genetic diversity. When such studies are employed across diverse groups in an array of communities, it may be difficult to discover common evolutionary and ecological processes associated with diversification. In order to identify taxa that have responded in a similar fashion to historical events, we conducted comparative phylogeographical analyses on a phylogenetically and ecologically limited set of taxa. Here, we focus on a group of squamate reptiles (snakes and lizards) that share similar ecological requirements and generally occupy the same communities in the western USA. At a gross level, deep genetic division in Contia tenuis, Diadophis punctatus, Elgaria multicarinata, the Charina bottae complex, and Lampropeltis zonata are often concordant in the Transverse Ranges, the Monterey Bay and Sacramento-San Joaquin Delta region, and the southern Sierra Nevada in California. Molecular clock estimates suggest that major phyletic breaks within many of these taxa roughly coincide temporally, and may correspond to important geological events. Furthermore, significant congruence between the phylogeographies of E. multicarinata and L. zonata suggests that the succession of vicariance and dispersal events in these species progressed in concert. Such congruence suggests that E. multicarinata and L. zonata have occupied the same communities through time. However, across our entire multi-taxon data set, the sequence of branching events rarely match between sympatric taxa, indicating the importance of subtle differences in life history features as well as random processes in creating unique genetic patterns. Lastly, coalescent and noncoalescent estimates of population expansion suggest that populations in the more southerly distributed clades of C. tenuis, D. punctatus, E. multicarinata, and L. zonata have been stable, while populations in more northerly clades appear to have recently expanded. This concerted demographic response is consistent with palaeontological data and previous phylogeographical work that suggests that woodland habitat has become more restricted in southern California, but more widespread in the North during Holocene warming. Future phylogeographical work focusing on allied and ecologically associated taxa may add insight into the ecological and evolutionary processes that yield current patterns of genetic diversity.     

Geographic Population Structure of the Sugarcane Borer,Diatraea saccharalis (F.) (Lepidoptera: Crambidae), in the Southern United States

The sugarcane borer moth, Diatraea saccharalis, is widespread throughout the Western Hemisphere, and is considered an introduced species in the southern United States. Although this moth has a wide distribution and is a pest of many crop plants including sugarcane, corn, sorghum and rice, it is considered one species. The objective was to investigate whether more than one introduction of D. saccharalis had occurred in the southern United States and whether any cryptic species were present. We field collected D. saccharalis in Texas, Louisiana and Florida in the southern United States. Two molecular markers, AFLPs and mitochondrial COI, were used to examine genetic variation among these regional populations and to compare the sequences with those available in GenBank and BOLD. We found geographic population structure in the southern United States which suggests two introductions and the presence of a previously unknown cryptic species. Management of D. saccharalis would likely benefit from further investigation of population genetics throughout the range of this species.     

Variation in Survival and Harvest Rates in Florida Mottled Duck

The Florida mottled duck (Anas fulvigula fulvigula) inhabits a relatively small range of approximately 90,000 km² within peninsular Florida, USA, and is threatened by habitat loss and genetic introgression with feral mallards (Anas platyrhynchos). Moreover, the Florida mottled duck population status has not been assessed for more than a decade. We used band-recovery and recapture data from 2000–2013 to examine geographic and demographic factors that influence the survival of Florida mottled ducks and to determine whether survival and harvest probabilities have changed over time. Mean survival probabilities were higher for birds banded in the southern portion of their Florida range than for those banded in the northern portion and higher for adult males than for adult females in both areas. Harvest probabilities increased in the northern extent of its range in Florida for adults and juveniles and remained relatively constant in the southern portion of its range during the study period. Mean harvest probabilities for adult males in both areas were higher than for adult females. Mean harvest probability for juvenile females was higher than that for juvenile males in the north but was similar between the sexes in the south. Our results suggest that mortality rates are generally greater in the northern portion of the Florida mottled duck range because of regional differences in habitat distribution and permanence and in how mottled ducks and humans use wetlands in these areas. We suggest increasing conservation efforts in the north portion of the Florida mottled duck range and improving inferences from leg banding by incorporating live recapture data. © 2020 The Wildlife Society.     

Gastrointestinal helminths of the northern bobwhite in Florida: 1968 and 1983

We collected 153 northern bobwhites (Colinus virginianus) over a 10-mo period from Tall Timbers Research Station near Tallahassee, Florida, USA. Five species of gastrointestinal helminths were encountered commonly (greater than 30% prevalence): Cyrnea colini, Raillietina cesticillus, R. colinia, Heterakis isolonche, and Trichostrongylus tenuis. Other helminths included Brachylaima sp., Rhabdometra odiosa, Mediorhynchus papillosis, Cheilospirura spinosa, Dispharynx nasuta, Gongylonema ingluvicola, and Tetrameres pattersoni. During the intervening 15 yr since the last year-round study of this population of birds, C. spinosa and T. pattersoni have declined markedly, and Strongyloides sp. probably has become extinct locally. Prevalence and intensity seem more likely to fluctuate in parasite species that have complex life cycles.     

Regeneration of photoreceptor organs in freshwater planarians at different levels of accumulation of natural methylmercury compounds

The effects of natural methylmercury compounds on regeneration of photoreceptor organs were studied in three freshwater planarians: Polycelis tenuis, Dugesia lugubris, and D. tigrina. Accumulation of methyl mercury in the planarian body suppressed regeneration of P. tenuis with numerous photoreceptor organs to a greater extent than in two other planarians that have only two eyes. High methyl mercury concentrations inhibited the restoration of photoreceptor organs in asexual and sexual D. tigrina races.     

Fibropapillomatosis in stranded green turtles (Chelonia mydas) from the eastern United States (1980-98): trends and associations with environmental factors

We examined data collected by the US Sea Turtle Stranding and Salvage Network on 4,328 green turtles (Chelonia mydas) found dead or debilitated (i.e., stranded) in the eastern half of the USA from Massachusetts to Texas during the period extending from 1980 to 1998. Fibropapillomatosis (FP) was reported only on green turtles in the southern half of Florida (south of 29 degrees N latitude). Within this region, 22.6% (682/3,016) of the turtles had tumors. Fibropapillomatosis was more prevalent in turtles found along the western (Gulf) coast of Florida (51.9%) than in turtles found along the eastern (Atlantic) coast of Florida (11.9%) and was more prevalent in turtles found in inshore areas (38.9%) than in turtles found in offshore areas (14.6%). A high prevalence of FP corresponded to coastal waters characterized by habitat degradation and pollution, a large extent of shallow-water area, and low wave energy, supporting speculation that one or more of these factors could serve as an environmental cofactor in the expression of FP. A high prevalence of FP did not correspond to high-density green turtle assemblages. Turtles with tumors were found most commonly during the fall and winter months, and the occurrence of tumors was most common in turtles of intermediate size (40-70-cm curved carapace length). Stranded green turtles with tumors were more likely to be emaciated or entangled in fishing line and less likely to have propeller wounds than were stranded green turtles without tumors. Turtles with and without tumors were equally likely to show evidence of a shark attack. The percent occurrence of tumors in stranded green turtles increased from approximately 10% in the early 1980s to over 30% in the late 1990s. Fibropapillomatosis was first documented in southernmost Florida in the late 1930s and spread throughout the southern half of Florida and the Caribbean during the mid-1980s. Because green turtles living in south Florida are known to move throughout much of the Caribbean, but are not known to move to other parts of the USA or to Bermuda, the spread and current distribution of FP in the western Atlantic, Gulf of Mexico, and Caribbean can be explained by assuming FP is caused by an infectious agent that first appeared in southern Florida. Aberrant movements of captive-reared turtles or of turtles that are released into areas where they were not originally found could spread FP beyond its current distribution.     

Effect of low temperatures on mortality and oviposition in conjunction with climate mapping to predict spread of the root weevil Diaprepes abbreviatus and introduced natural enemies

The tropical root weevil, Diaprepes abbreviatus (L.), has been a pest of citrus and ornamental plants since its introduction into Lake County, FL, in 1964. Since then, it has colonized the Florida peninsula to the south of its point of introduction but has not expanded its range to the north. A lower threshold for oviposition by D. abbreviatus was estimated as 14.9 degrees C. Eggs were highly susceptible to cold, with 95% mortality (LTime95) occurring in 4.2 d at 12 degrees C. Relative susceptibility of life stages to cold was eggs > pupae > larvae > adults. Archived weather data from Florida were examined to guide a mapping exercise using the lower developmental threshold for larvae (12 degrees C) and the lower threshold for oviposition (15 degrees C) as critical temperatures for mapping the distribution of D. abbreviatus and the potential for establishment of egg parasitoids. Probability maps using the last 10 yr of weather data examined the frequency of at least 10, 15, 20, 25, or 30 d per winter when soil temperature was 相似文献   

Diatom community structure on commercially available ship hull coatings

Diatoms are primary colonizers of both antifouling and fouling-release ship hull coatings. There are few published studies which report on diatom community development on modern ship hull coatings. This study reports diatom communities on eight commercial marine ship hull coatings exposed at three static immersion sites along the east coast of Florida, viz. Daytona, Sebastian, and Miami. The coatings tested were three ablative copper systems (Ameron ABC-3, International BRA-640, and Hempel Olympic 76600), two copper-free biocidal systems (E-Paint SN-1, Sherwin Williams HMF), and three fouling-release (FR) systems (International Intersleek 700, International Intersleek 900, and Hempel Hempasil). One hundred and twenty-seven species comprising 44 genera were identified, including some of the more commonly known foulers, viz. Achnanthes, Amphora, Cocconeis, Entomoneis, Licmophora, Melosira, Navicula, Nitzschia, Synedra, and Toxarium. A significant difference was seen among sites, with the more estuarine site, Sebastian, having lower overall diatom abundance and higher diversity than Daytona and Miami. Copper coatings were primarily fouled by Amphora delicatissima and Entomoneis pseudoduplex. Copper-free coatings were fouled by Cyclophora tenuis, A. delicatissima, Achnanthes manifera, and Amphora bigibba. FR surfaces were typified by C. tenuis, and several species of Amphora. The presence of C. tenuis is new to the biofouling literature, but as new coatings are developed, this diatom may be one of many that prove to be problematic for static immersion. Results show coatings can be significantly influenced by geographical area, highlighting the need to test ship hull coatings in locations similar to where they will be utilized.     

An update on the distribution of Parelaphostrongylus tenuis in the southeastern United States

An update is presented on the distribution of the meningeal worm (Parelaphostrongylus tenuis) of white-tailed deer (Odocoileus virginianus) in the southeastern United States. The parasite is widely distributed and common in all or much of Arkansas, Kentucky, Louisiana, Maryland, North Carolina, Tennessee, Virginia and West Virginia. It is also common in the northern half of Alabama and Georgia. In contrast, it is rare or absent along the Atlantic and Gulf coastal plains of Alabama, Georgia, Mississippi and South Carolina. It has been collected from a single deer in Florida.     

A role for sulfated polysaccharide recognition in sponge cell aggregation

Molecules binding sulfated polysaccharides were detected as lectins in cholate lysates of cells from twelve sponge species. Each species exhibited a unique binding profile. The pattern of binding indicated that the specificity was most probably determined by the orientation of the sulfate groups on the polysaccharide chains. Cells from each of the three species examined in more detail were found to express sulfated polysaccharide-binding molecules at their surface and at least one of the polysaccharides recognized was found to inhibit the reaggregation of cells from each species. Moreover, in all but one instance, lectins for the inhibitory polysaccharide were both detected in cell lysates and shown to be expressed at the cell surface. Sulfated polysaccharides, therefore, appeared to be involved in cell interaction events in the Porifera. This conclusion was confirmed by the isolation via ion exchange chromatography of an endogenous polysaccharide from an O. tenuis cell extract. This molecule contained uronic acid and hexose units in a ratio of 2:1, 11.9% sulfur and less than 0.5% protein. It inhibited the aggregation of O. tenuis cells and the agglutination of dextran-sulfate- and polyvinyl-sulfate-coupled erythrocytes by O. tenuis cell lysates. O. tenuis cell aggregation was also inhibited by polyvinyl sulfate and dextran sulfate and molecules binding these compounds were expressed on the surface of O. tenuis cells. Thus, is was probable that the cell surface receptor for polyvinyl sulfate and dextran sulfate and isolated sponge sulfated polysaccharide are one and the same. Finally, using a dextran sulfate affinity procedure, a 35 kD dextran-sulfate-binding protein was isolated from the surface of O. tenuis cells. The possibility that the polysaccharide isolated from O. tenuis cell extracts in the absence of calcium is the monomeric form of a cell aggregation-enhancing factor is discussed.     

Distribution and ecology of meningeal worm,Parelaphostrongylus tenuis (Nematoda), in northcentral North America

Meningeal worm (Parelaphostrongylus tenuis), a common nematode parasite in white-tailed deer (Odocoileus virginianus) and pathogenic for several species of ungulates in eastern North America, is not known to occur in the west. Heads of 1,902 white-tailed deer were examined for adult meningeal worm to determine geographic distribution of the parasite in Saskatchewan and Manitoba (Canada) and North Dakota (USA). Finding the parasite in a deer in eastern Saskatchewan near the Manitoba border established the current northern and western limits in Canada. Prevalence of infection was < 1, 18.6, and 8.2% in Saskatchewan, Manitoba, and North Dakota, respectively. Infected deer occurred throughout southern Manitoba and eastern North Dakota. Distribution appears to have changed little since the last published survey for P. tenuis in the region in 1972. We examined precipitation, temperature, deer density, and forest cover as likely correlates to prevalence and distribution of P. tenuis. Deer management units used for hunting purposes were the scale of analysis in the three jurisdictions. Presence of P. tenuis was positively correlated with precipitation during frost-free periods and deer density, and it was negatively correlated with winter and spring temperatures. Landscapes with > 25 and < 75% forest cover were most likely to have infected deer. Low rainfall and low density of white-tailed deer likely influence the westernmost limit of P. tenuis.     

Sexual ornamentation relates to immune function in male red grouse Lagopus lagopus scoticus

Sexual ornaments may enable females to discriminate amongst potential mates and choose those having either fewer parasites, or those which are more immunocompetent, or better able to cope with parasites. Tetraonid birds exhibit supra-orbital combs that function in both intra-sexual competition and mate choice. Through a correlative and experimental approach we investigated whether comb size of male red grouse Lagopus lagopus scoticus was related to infection intensity by their main parasite, the gastro intestinal nematode Trichostrongylus tenuis , and to immune function. We first looked at the relationships between immune function, parasite infection and condition. We found that spleen mass, an indirect measure of immune response, correlated positively with T. tenuis load, and negatively with condition. Cell-mediated immunity, a measure of immune defence, correlated positively with condition, and although not significantly related to T. tenuis load, increased when nematode parasites were experimentally reduced. Secondly, we investigated whether comb size was related to condition, T. tenuis load or immune function. Comb size was not significantly related to T. tenuis infection and did not change significantly after nematode parasite removal. However, males with bigger combs were in better condition, had a lighter spleen, a lighter spleen than expected from their T. tenuis load and had greater cell-mediated immunity. The findings suggest that comb size relates to immune function rather than T. tenuis parasite infection intensity. Males with bigger combs are likely to be of higher phenotypic quality because they are more immunocompetent and might be better able to cope with the detrimental effects of parasites.     

Reproductive Biology of the Introduced Mayan cichlid, Cichlasoma urophthalmus, Within an Estuarine Mangrove Habitat of Southern Florida

We investigated the reproductive biology of the Mayan cichlid, Cichlasoma urophthalmus, for twenty consecutive months in a southern Florida mangrove creek and compared it to that of available published accounts where this species is native. Mayan cichlid reproduction occurred during a period of the year when physical conditions facilitated the best growth and survival of the young, and was influenced more by changes in water level and salinity than by temperature. Most nests were observed along mangrove shorelines in April. The majority of reproduction and parental care of the young followed in May, and was completed by June when rising water levels flooded shallow habitats and dispersed young-of-year fish. Mayan cichlids in Florida became reproductively mature at a greater size than in native regions, but produced roughly the same number of eggs at a given body mass. The similarity of environmental conditions between southern Florida and areas where Mayan cichlids naturally occur imparts a very favorable reproductive potential for this species in southern Florida, and facilitates their continued presence within the ichthyofauna of the region.     

Entry of migrating American eel leptocephali into the Gulf Stream system

Abundance, size and depth distributions of American eel(Anguilla rostrata) leptocephali collected in four transects across the Florida Current between the Straits of Florida and Cape Hatteras, North Carolina, were examined in order to assess the relative importance of two migration routes into the Gulf Stream system. A nine-fold increase in the abundance and an increase in the mean length of leptocephali collected in the Florida Current north of the Straits of Florida indicate that most leptocephali enter the Gulf Stream system directly from the Sargasso Sea rather than by a more southern route through the Bahama Islands. Leptocephali were concentrated in the upper 140 m at night and upper 350 m during the day. Wide vertical ranges in daytime collections precluded more refined estimation of vertical distribution. The collection of eight small leptocephali (11 to 17 mm total length) in the western Caribbean Sea is discussed in relation to the origin of leptocephali taken in the Straits of Florida.