Many aquatic animals deposit fertilized eggs in adherent clutches or gelatinous masses. Egg aggregation carries certain risks, including the potential for inadequate oxygen supply to embryos. Physical and biological conditions alter such risks. We examined the effects of light levels and associated photosynthetic organisms on the distribution of oxygen inside gelatinous egg masses of four tempe...

The infectivity and development of four populations of Meloidogyne hapla were compared, at three temperatures, on tomato and two varieties of cucumber. A population from Canada produced few root-galls on cucumber and, except at 24 C, no larvae developed into adult females and produced egg masses. In contrast, a population with 45 chromosomes from America produced many galls on cucumber and smal...

A procedure for extracting eggs of Meloidogyne spp. from soil was developed by modifying and combining certain existing techniques. Egg masses were elutriated from the soft, gelatinous matrices of the egg masses were dissolved, and the dispersed eggs were stained to facilitate counting. Data on egg population densities thus obtained facilitate the study of population dynamics of Meloidogyne spp...

Meloidogyne javanica is an important nematode pest of pigeonpea. Thirty-four pigeonpea cultivars and 227 germplasm accessions were evaluated for resistance to M. javanica based on number of galls, egg masses, size of galls, and area of root covered with galls. Galls were not formed on 75% of the cultivars, and no egg masses were observed on the roots of four cultivars (UPAS 120, Pant A3, CO 1, ...

Environ. Entomol. 15: 501-506 (1986) ABSTRACT Studies were conducted in commercial sweet corn fields in upstate New York to collect information for developing a sampling protocol for egg masses and larvae of European corn borer (ECB), Ostrinia nubilalis (Hubner). Information was collected on 1) aggregation of populations in portions of the field (e.g., aggregation along borders), 2) distributio...

For organisms with complex life histories, carry-over effects (COEs) can manifest between life stages, when conditions experienced by one stage influence the next, as well as trans-generationally, when the parental environment affects offspring. Here we used multiple global change-associated stressors to examine both forms of COE simultaneously in an intertidal limpet with mixed development (i....

Two experiments were conducted to evaluate the efficacy of sodium carbonate peroxyhydrate (SCP) in improving the hatching success of channel catfish Ictalurus punctatus when used as a prophylactic chemotherapeutant during egg incubation. In the first experiment, the efficacy of SCP was evaluated in 379-L aluminum incubation troughs similar to those used in commercial hatcheries. Egg masses trea...

Research on interspecific competitive interactions among insect parasitoids has often been characterized by laboratory studies in which host insects are exposed to female parasitoids of different species in various sequences and combinations. In the last years, an increasing number of studies have investigated interspecific interactions under field and semi-field conditions although just a few ...

Oxygen concentrations in gelatinous egg masses of two species of opisthobranch gastropods were examined with microelectrodes. Embryos in central positions are near the limit of the oxygen supply required for development. This limit is approached despite a diffusion constant for oxygen in masses that is close to that in water. Closed-chamber respirometry shows that oxygen is consumed by masses i...