The genus Mixodiaptomus Kiefer, 1932 (Copepoda,Diaptomidae) in Spain

The distribution of the Calanoid genus Mixodiaptomus was studied in a large number of pools and small lakes scattered over Spain. Four species occur: M. incrassatus, M. kupelwieseri, M. ortizi and M. laciniatus, the latter in 2 subspecies (M. laciniatus laciniatus and M. laciniatus atlantis). M. ortizi is described as a new species. M. laciniatus lives in mountains, while all other species occur in the plains. M. incrassatus is found all over the country, M. kupelwieseri only in the eastern part of Catalonia, M. laciniatus atlantis in Andalucia and M. ortizi in the central lands called Mesetas. All live in little mineralized waters and only M. incrassatus and M. laciniatus atlantis occur in clayey waters.     

Taxonomy and biogeography of the fiddler crabs (Ocypodidae: Genus Uca) of the Atlantic and Gulf coasts of eastern North America

Fifteen species of fiddler crabs are reported for eastern North America between Massachusetts and Quintana Roo, Mexico. Thirteen occur in the United States and 11 in Mexico, with eight in common to the two countries. Of 13 species in the Gulf of Mexico, five are endemic and a sixth is restricted largely to the peninsulas of Florida and Yucatan. The status of U. rapax in the northern Gulf remains to be resolved. Range limits of most species approximate one or the other of two sets of intersecting thermal and geological boundaries that subdivide the Gulf of Mexico along north-south and east-west axes. Species belonging to subgenus Minuca tend to replace one another at the thermally-controlled Carolinian-Caribbean marine biotic boundary across the Florida peninsula and northern Gulf. However, only U. minax of all the North American fiddler crabs exhibits the classical disjunct Carolinian distribution, and this appears basically to reflect the discontinuous distribution of temperate salt marshes that are the habitat of the species. Distributions of species belonging to subgenus Celuca adhere for the most part to the subdivision of the Gulf into western terrigenous and eastern carbonate sedimentary provinces. The northern transition occurs in the vicinity of Apalachee Bay and the southern at Laguna de Terminos. A third distributional pattern is shown by U. subcylindrica , a specialized endemic species of the hypersaline Laguna Madre system of the western Gulf. The level of endemism in the fiddler crabs is relatively high in comparison with that of other marine groups within the Gulf of Mexico. This may be a consequence of the adaptations of fiddler crabs as specialized deposit feeders to regional differences in climatic and edaphic characteristics of a marginally marine upper shore habitat. The distributional patterns of the endemics could prove useful in reconstructing palaeoecological events of evolutionary significance within the Gulf of Mexico.     

Population dynamics,production and angling catch of brown trout,Salmo trutta,in a mature upland reservoir in mid-Wales

Synopsis The brown trout in Llyn Frongoch, a mature upland reservoir, and its nursery stream was sampled during 1983. The stream stock consisted largely of the 1983 and 1982 year classes, with fish reaching mean lengths of 7.0 and 11.6 cm at one and two years of age. The size and biomass of the stream stock at the beginning of 1983 and 1984 were estimated to be 120 and 125 (1.20 and 1.25 fish m^–2) and 1.41 and 0.69 kg (14.1 g m^–2 and 6.9 g m^–2) respectively. Annual stream production ranged from an estimated minimum of 2.49 kg (24.9 g m^–2) to an estimated maximum of 4.59 kg (45.9 g m^–2). Both downstream and upstream movements of 0+ juveniles were recorded. The adult spawning stock was estimated at 79 males and 32 females, a sex ratio of 2.5:1, with most spawners belonging to the 1980 yearclass. The average size of the lake stock over the year was estimated to be 1 650 (229 fish ha^–1) or 250.8 kg (34.8 kg ha^–1). The 1980 yearclass was predominant; there were few fish older than five years. Seasonal variations in netting catches suggested movements to and from the littoral region. Growth in the lake was moderately fast, with fish reaching mean lengths of 21.7 and 27.2 cm by three and four years of age. Fish entering the lake after one year appeared to grow faster than fish which remained in the stream for two years. Annual production in the lake was estimated at 136.7 kg (19.0 kg ha^–1). The total angling catch for the season was estimated to be 62.6 kg (8.7 kg ha^–1).     

Resistance of wild wheat to stripe rust: Predictive method by ecology and allozyme genotypes

From 114 accessions of wild emmer wheat from 11 sites in Israel, known for their allozymic variation (Nevo & al. 1982), individual genotypes were tested for resistance to one isolate of stripe rust both in the seedling stage in a growth chamber and in the adult plant stage in the field. The results indicate that resistance to stripe rust in seedlings and adults are significantly correlated (r_s = 0.40, p < 0.001). Genetic polymorphisms of resistance to stripe rust vary geographically and are predictable by climatic, as well as allozymic markers. Three variable combinations of rainfall, evaporation, and temperature explain significantly 0.40–0.53 of the spatial variance in disease resistance to stripe rust, suggesting the operation of natural selection. Several allozyme genotypes are significantly associated with disease resistance. We conclude that natural populations of wild emmer wheat in Israel contain large amounts of disease resistance genes. These populations could be effectively screened and then utilized by the phytopathologist for identifying resistant genotypes and producing new resistant cultivars.Patterns of Resistance of Wild Wheat to Pathogens in Israel II.     

Dispersion and Distribution of Pratylenchus scribneri and Hoplolaimus galeatus in Soybean Fields

Examination of dispersional characteristics of Pratylenchus scribneri and Hoplolaimus galeatus indicated that there were patches within soybean fields in which both survival and reproduction wexe enhanced in spite of apparent homogeneity of soil type and topography. Treatment with carbofuran reduced the patchiness (or increased the dispersion) for H. galeatus while it had the opposite effect for P. scribneri. P. scribneri was less highly dispersed in conventional tillage plots than in the zero tillage plots. Populations from quadrats contained entirely within the patches could be described by the normal distribution (in the case of P. scribneri) or by the Poisson distribution (in the case of H. galeatus), while populations from quadrats contained entirely outside the patches could be described by the Poisson distribution for both nematodes. None of the distributions tested (Poisson, normal, negative binomial, Neyman''s) gave an adequate fit when populations from both inside and outside the patches were considered together. In all instances, log₁₀ and ln transformations reduced the goodness of fit of the data to all of the distributions tested. Even with logarithmic transformations, parametric statistics were not appropriate for analysis of data in most instances.     

Topographic control of vegetation in a mountain big sagebrush steppe

Mountain big sagebrush steppes in Wyoming have strong spatial patterning associated with topography. We describe the spatial variability of vegetation in a sagebrush steppe, and test the relationship between topography and vegetation using canonical correlation. Results of the analysis suggest that the main control over vegetation distribution in this system is wind exposure. Exposed sites are characterized by cushion plant communities and Artemisia nova, and less exposed sites by the taller sagebrush species Artemisia tridentata ssp. vaseyana. Topographic depressions and leeward slopes are characterized by aspen stands and nivation hollows. Measurements of soil microclimate suggest that a major influence of topographic position on vegetation is snow redistribution and its effect on soil moisture and temperature.Abbreviations ARNO Artemisia nova - ARTRW Artemisia tridentata ssp. wyomingensis - ARTRV Artemisia tridentata ssp. vaseyana - PUTR Purshia tridentata - RIP riparian community - POTR Populus tremuloides - NIV nivation hollow community     

Effects of weather and feeding on body temperature and activity in the snake Masticophis flagellum

1. 1.|Body temperature (T_b) and activity of the snake Masticophis flagellum were studied by radiotelemetry in an outdoor enclosure.

2. 2.|Mean diurnal T_b varied little over a wide range of weather conditions, but weather variation was accompanied by major changes in sun exposure and in the timing and duration of activity.

3. 3.|Recently fed snakes reduced activity and exhibited neither a thermophilic response nor increased precision of thermoregulation compared to fasting snakes.

Infrasectional systematics of the genus Sideritis L. section Sideritis (Lamiaceae)

RIVERA NUÑEZ, D., OBON DE CASTRO, C., TOMAS-LORENTE, F., FERRERES, F. & TOMAS-BARBERAN, F. A., 1990. Infrasectional systematics of the genus Sideritis L. section Sideritis (Lamiaceae). A new taxonomic division of the section Sideritis is proposed on the basis of morphological, cytological and chemical characters. The following subsections art-recognized: Grandiflora, Ovata, Camarae, Linearifolia, Gymnocarpae, Stachydioides, Lacaitae, Hirsuta, Chamaedryfolia, Arborescens, Flavovirens, Leucantha, Angustifolia, Serrata and Scordioides . Possible evolutionary pathways are discussed.