Benthic boom: Understanding larval insect colonization in Moorea, French Polynesia

Insects are important in assessing ecosystem quality and health. Current climate change models predict that in the next one hundred years, intense storms separated by long periods of drought will frequent French Polynesia. Variation in water availability may be difficult for many stream insects to cope with. Studying insect response after a disturbance as well as assessing their current distribution and abundance can help us understand greater ecological interactions and allow us to make predictions about future assemblages. The recolonization rate and habitat preference of Simuliidae and Chironomidae larvae were measured in a high elevation stream on Moorea, French Polynesia. Insect recolonization was measured 1, 3, and 6 days after an artificial disturbance event, and habitat preference was determined through the use of 3 introduced substrates: streamside moss, synthetic moss, and an empty control. Habitat preference was also evaluated through the comparison of larval densities across both experiments. Ultimately both Simuliidae and Chironomidae larvae were shown to return to baseline abundance 3 days after a disturbance event. Furthermore, chironomids preferred the synthetic moss substrate to all other habitats, while simuliids preferred the empty control compared to the moss treatment. This likely indicates that the chironomids live within the submerged moss while simuliids live on a rocky substrate. It also suggests that both species can live in a variety of environments and can adapt well to changing conditions.

Benthic boom: Understanding larval insect colonization in Moorea, French Polynesia

Insects are important in assessing ecosystem quality and health. Current climate change models predict that in the next one hundred years, intense storms separated by long periods of drought will frequent French Polynesia. Variation in water availability may be difficult for many stream insects to cope with. Studying insect response after a disturbance as well as assessing their current distribution and abundance can help us understand greater ecological interactions and allow us to make predictions about future assemblages. The recolonization rate and habitat preference of Simuliidae and Chironomidae larvae were measured in a high elevation stream on Moorea, French Polynesia. Insect recolonization was measured 1, 3, and 6 days after an artificial disturbance event, and habitat preference was determined through the use of 3 introduced substrates: streamside moss, synthetic moss, and an empty control. Habitat preference was also evaluated through the comparison of larval densities across both experiments. Ultimately both Simuliidae and Chironomidae larvae were shown to return to baseline abundance 3 days after a disturbance event. Furthermore, chironomids preferred the synthetic moss substrate to all other habitats, while simuliids preferred the empty control compared to the moss treatment. This likely indicates that the chironomids live within the submerged moss while simuliids live on a rocky substrate. It also suggests that both species can live in a variety of environments and can adapt well to changing conditions.

Incorporation of Protease K into Larval Insect Membrane Vesicles Does Not Result in Disruption of Integrity or Function of the Pore-Forming Bacillus thuringiensisδ-Endotoxin

ABSTRACT Bacillus thuringiensis δ-endotoxins insert into the brush border membranes of insect larval cells to form ion channels. A possible interaction of these toxins with a cytoplasmic component was examined by preloading vesicles from insect larval cells with protease K followed by incubation with toxin. There was no evidence for toxin antigens smaller than the intact toxin in extracts of solubilized vesicles, nor was there an effect of the inclusion of protease K on either of two functional properties, the formation of toxin aggregates or of ion pores. These toxins, physically and functionally, appear to be confined to the membrane.