Food Uptake by the Insect-Parasitic Nematode, Sphaerularia bombi (Tylenchida)

Area of Science:

• Parasitology
• Insect Pathology
• Cell Biology

Background:

• Sphaerularia bombi is an insect parasite that infects bumblebees.
• The parasite's uterus everts into the host's hemocoel, forming an independent organ.

Purpose of the Study:

• To investigate the cellular mechanisms of nutrient uptake and digestion in the parasitic Sphaerularia bombi.

Main Methods:

• Electron microscopy was used to examine the uterine cells, ovary, and oviduct of Sphaerularia bombi.

Main Results:

• Uterine cells exhibit specialized surface indentations and cytoplasmic extensions facilitating pinocytosis and intracellular digestion.
• Ovary and oviduct surfaces are modified into lobelike projections, suggesting enhanced nutrient absorption.
• Electron-dense droplets were observed in the ovary-oviduct tissue and developing eggs, indicating nutrient transfer.

Conclusions:

• Nutrient acquisition in Sphaerularia bombi involves initial intracellular digestion via pinocytosis in uterine cells.
• Nutrients are absorbed and processed by the ovary-oviduct tissue before being incorporated into developing eggs.