Herbivory in (Cactaceae): Do Parasitoids Provide Indirect Defense or a Direct Advantage?

Plants respond to herbivory in diverse, complex ways, ranging from avoidance or tolerance to indirect defense mechanisms such as attracting natural enemies of herbivores, i.e., parasitoids or predators, to strengthen their defense.

Diesel effects on some population attributes of Orthonychiurus folsomi Schäffer 1900 (Collembola: Onychiuridae) under laboratory conditions.

Soil contamination by hydrocarbons and its effects on population health and welfare is a growing concern, especially in urban environments with industrial activity. Indicator species complement the information obtained from the measurement of environment quality by using physicochemical variables. The objective of this study was to evaluate the response of a springtail species that could be potentially used as a bioindicator of hydrocarbon contaminated sites.

Soil microarthropods and their relationship to higher trophic levels in the Pedregal de San Angel Ecological Reserve, Mexico.

Soil fauna is essential for ecosystem dynamics as it is involved in biogeochemical processes, promotes nutrient availability, and affects the animal communities associated with plants. In this study, we examine the possible relationship between the soil microarthropod community on foliage production and quality of the shrub Pittocaulon praecox. We also examine the arthropods associated to its foliage, particularly the size of the main herbivores and of their natural enemies, at two sites with contrasting vegetation cover and productivity.

Seed dispersal of desert annuals.

We quantified seed dispersal in a guild of Sonoran Desert winter desert annuals at a protected natural field site in Tucson, Arizona, USA. Seed production was suppressed under shrub canopies, in the open areas between shrubs, or both by applying an herbicide prior to seed set in large, randomly assigned removal plots (10-30 m diameter). Seedlings were censused along transects crossing the reproductive suppression borders shortly after germination.

Foliole movement and canopy architecture of Larrea tridentata (DC.) Cov. in Mexican deserts.

The creosote bush (Larrea tridentata) is a common desert perennial with bifoliate, amphistomatic, divaricate leaves. The leaves can vertically close their folioles and vary their profile with respect to direct solar radiation. Field data from different Mexican deserts showed a significant correlation between foliole aperture and mean foliole inclination: in plants in which folioles were more open, the foliole surfaces were less vertical.