Continuing investigations on the South Amherst Drosophila melanogaster natural population following the significant decline and recovery of lethal (le) and semilethal (sle) frequencies in the late 1960's (Ives, 1970) show that the population has been remarkably stable although it contains MR (male recombination) and/or P DNA elements (Kidwell et al., 1977a; Green, 1980). A 13-year study affirms that the lethals present are nonrandomly distributed along the second chromosome and deficient on the right; they differ significantly in distribution from spontaneous (Ives, 1973) and δ-induced lethals (Minamori and Ito, 1971). Between 1970 and 1977, a total of 4,083 second chromosomes from the Markert subpopulation were analyzed; 28.9% of the chromosomes were lethal and 7.25% were semilethal in homozygous condition. Frequencies are similar for early summer and late fall collections although the rate of allelism among lethals is significantly higher in early summer than in late fall. For the large fall (1970-1979) Porch site population, 2,519 second chromosomes were analyzed; 29.5% were lethal and 8.0% were sublethal as homozygotes; the rate of allelism among lethals was 1.50%. At Hockanum, 1977-1983, lethal and semilethal frequencies were lower; the rate of allelism among lethals was 1.43%. The chromosome map distribution of lethals does not change between summer and late fall at Markert. The overall distributions of lethals at the Markert and Hockanum sites are similar. In tests for male recombination (MR) activity in the population over a 6-year period, a total of 0.47% recombinants were observed; these were uniformly distributed along the second chromosome. Comparisons are made with other long studied D. melanogaster populations.
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http://dx.doi.org/10.1111/j.1558-5646.1986.tb05752.x | DOI Listing |
Climate change poses significant consequences for temperate bat species, potentially altering their distribution ranges and generating novel interactions among species sharing similar ecological niches. Recent observations suggest distribution range expansion in the Palearctic aerial hawking bat, , prompting an investigation into its interaction with , a northern Palearctic species overlapping with the previous in many ecological characteristics. This study examines the spatiotemporal variations between the two boreal bat species to form an evidence-based background onto which future research on, e.
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January 2025
Tethys Research Institute, Viale G.B. Gadio 2, 20121, Milan, Italy.
To investigate the seasonal migratory behaviour of spinetail devil rays, Mobula mobular, across the Mediterranean Sea, we used satellite telemetry to track nine individuals between 2016 and 2021. The species is listed as Endangered in the IUCN's Red List of Threatened Species and appears to be most vulnerable to fishing impacts when gathering in large assemblages. The only known targeted devil ray fishery harvests significant numbers each winter off Gaza.
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January 2025
Section of Ecology, Department of Biology, University of Turku, Turku, Finland.
The hoarding behaviour of animals has evolved to reduce starvation risk when food resources are scarce, but effects of food limitation on survival of hoarding animals is poorly understood. Eurasian pygmy owls (Glaucidium passerinum) hoard small mammals and birds in natural cavities and nest boxes in late autumn for later use in the following winter. We studied the relative influence of the food biomass in hoards of pygmy owls on their over-winter and over-summer apparent survival.
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January 2025
Facultad de Ciencias, Universidad Autónoma del Estado de México, Toluca, Estado de México, Mexico.
Heterogeneous environments provide different daily and seasonal thermal conditions for snakes, resulting in temporal and spatial variations in body temperature (Tb). This study analyzes the Tb of in the forest and grassland of a Mexican locality through daily and seasonal profiling. The patterns were obtained from seminatural enclosures in the field with a point sampling strategy to analyze temporal and spatial variations in Tb.
View Article and Find Full Text PDFPlant Biol (Stuttg)
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Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Campus de Bellaterra (UAB) Edifici C, Cerdanyola del Vallès, Spain.
Tree responses to drought are well studied, but the interacting effects of drought timing on growth, water use, and stress legacy are less understood. We investigated how a widespread conifer, Scots pine, responded to hot droughts early or late in the growing season, or to both. We measured sap flux, stem growth, needle elongation, and leaf water potential (Ψ) to assess the impacts of stress timing on drought resilience in Scots pine saplings.
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