Maternal size and body condition predict the amount of post-fertilization maternal provisioning in matrotrophic fish.

Maternal effects often provide a mechanism for adaptive transgenerational phenotypic plasticity. The maternal phenotype can profoundly influence the potential for such environmentally induced adjustments of the offspring phenotype, causing correlations between offspring and maternal traits. Here, we study potential effects of the maternal phenotype on offspring provisioning prior to and during gestation in the matrotrophic live-bearing fish species .

Environmental change, shifting distributions, and habitat conservation plans: A case study of the California gnatcatcher.

Many species have already experienced distributional shifts due to changing environmental conditions, and analyzing past shifts can help us to understand the influence of environmental stressors on a species as well as to analyze the effectiveness of conservation strategies. We aimed to (1) quantify regional habitat associations of the California gnatcatcher (); (2) describe changes in environmental variables and gnatcatcher distributions through time; (3) identify environmental drivers associated with habitat suitability changes; and (4) relate habitat suitability changes through time to habitat conservation plans. Southern California's Western Riverside County (WRC), an approximately 4,675 km conservation planning area.

Gene flow from an adaptively divergent source causes rescue through genetic and demographic factors in two wild populations of Trinidadian guppies.

Genetic rescue, an increase in population growth owing to the infusion of new alleles, can aid the persistence of small populations. Its use as a management tool is limited by a lack of empirical data geared toward predicting effects of gene flow on local adaptation and demography. Experimental translocations provide an ideal opportunity to monitor the demographic consequences of gene flow.

Sex-specific genetic differences in endurance swimming of Trinidadian guppies.

Swim performance is considered a main fitness-determining trait in many aquatic organisms. Swimming is generally the only way most aquatic prey can escape predation, and swimming capacity is directly linked to food capture, habitat shifts, and reproduction. Therefore, evolutionary studies of swim performance are important to understand adaptation to aquatic environments.

Effects of siblings on reproductive maturation and infanticidal behavior in cooperatively breeding Mongolian gerbils.

Mongolian gerbils living with their natal families undergo delayed reproductive maturation while helping to rear their younger siblings, whereas those housed away from their natal families may mature earlier but often respond aggressively to unfamiliar pups. We tested whether cohabitation with pups contributes to reproductive suppression and inhibition of infanticidal behavior, using young males and females housed with (1) their parents and younger siblings (pups), (2) parents without pups, (3) mixed-sex littermate groups, or (4) mixed-sex groups of unrelated peers. Maturation in males was inhibited by cohabitation with the parents, while maturation in females was further suppressed in the presence of pups.

Effects of Protective Fencing on Birds, Lizards, and Black-Tailed Hares in the Western Mojave Desert.

/ Effects of protective fencing on birds, lizards, black-tailed hares (Lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA.

The Primary Egg Envelope of the Anuran Lepidobatrachus laevis: Physicochemical and Macromolecular Alterations During Development: (egg envelopes).

The coelomic egg envelope (CE) of the frog Lepidobatrachus laevis has a network of fibrillar bundles which disperse after transit through the oviduct. Following oviposition, the egg vitelline envelope (VE) has an additional amorphous zone on the exterior surface. The fertilization envelope (FE) formed after fertilization, appears to be very similar to the VE.

Structure and Macromolecular Composition of the Jelly Coats of the Urodele Ambystoma mexicanum: (egg envelopes).

Cleavage-stage embryos of the neotenic urodele Ambystoma mexicanum are surrounded by a fertilization envelope and four macroscopic jelly coats termed J (innermost) through J (outermost). In sections prepared for light microscopy, each of the jelly layers stained with protein stains and the periodic acid-Schiff's reagent, but only J stained with alcian blue at pH 2.5.