Behavior such as ontogenetic vertical migration (OVM) limits the transport of marine larvae with short pelagic larval durations (PLDs), but its effect on the supposed long-distance dispersal of larvae with long PLDs is unknown. We conducted laboratory tests of ontogenetic change in larval ph ototaxis and examin ed size-specific patterns of larval distribution in the plankton to characterize OVM...

To determine whether increased migration is associated with an increase in incidence of toxocariasis (visceral larva migrans), we analyzed clinical data obtained from immigrants from Latin America. Although infection with Toxocara sp. roundworm larvae is distributed worldwide, seroprevalence is highest in tropical and subtropical areas.

Metamorphosis is both an ecological and a developmental genetic transition that an organism undergoes as a normal part of ontogeny. Many organisms have the ability to delay metamorphosis when conditions are unsuitable. This strategy carries obvious benefits, but may also result in severe consequences for older larvae that run low on energy. In the marine environment, some lecithotrophic larvae ...

The migration of larvae of Ascaris lumbricoides from the intestine through the lungs and bronchial tree into the oesophagus and back into the intestine is a well-known feature of the life cycle of this nematode. The passage through the lungs remains often symptomless, but, in an investigation on experimental infection in man, Takata (1951) found cough in 71-4% of those infected with human ascar...

European eels (Anguilla anguilla) undertake a approximately 5000-kilometer (km) spawning migration from Europe to the Sargasso Sea. The larvae are transported back to European waters by the Gulf Stream and North Atlantic Drift. However, details of the spawning migration remain unknown because tracking eels in the Atlantic Ocean has, so far, eluded study. Recent advances in satellite tracking en...

Advantages of dispersal on the scales that are possible in a long pelagic larval period are not apparent, even for benthic species. An alternative hypothesis is that wide dispersal may be an incidental byproduct of an ontogenetic migration from and then back to the parental habitat. Under this hypothesis, the water column is a better habitat than the bottom for early development. Because the pa...

The diel vertical migration (DVM) of the whole plankton community was investigated in the central and coastal Irish Sea. Generally, more than 60% of the plankton did not perform significant DVM. A correlation analysis of the weighted mean depths of different organisms and their potential predators suggested relationships between 2 groups: Oithona spp., copepod nauplii and fish larvae, and Calan...

Anthelmintic bioactivity against gastrointestinal nematodes has been associated with leguminous forages supporting the hypothesis of a role of condensed tannins. However, the possibility that other compounds might also been involved has received less consideration. Using bio-guided fractionation, the current study aimed at characterizing the biochemical nature of the active compounds present in...

The aim of the study was to investigate the histopathologic lesions caused by the migration of Ascaris suum larvae through lung. Fragments of the lung were collected from a number of 10 swine (four months old), and histologically processed. Animals in this study were divided into 2 groups of 5 individuals: a group artificially infested with 1000 eggs of Ascaris suum, and another control group. ...