Simplified membrane feeding of bloodsucking triatomines (Hemiptera: Reduviidae).

Laboratory-reared hematophagous triatomines that are the main vectors of Chagas disease are generally fed on small vertebrates or on blood-filled membrane devices. Such devices allow a large-scale rearing of these vectors without sacrificing host animals but are almost always expensive, fragile, not easily purchased, and usually difficult to use because they need to be sterilized before and carefully cleaned after each feeding. We present here a simple device to feed triatomines that is composed of a circular series of alternating short pieces of stainless steel and silicon tubing connected to a pump that circulates water heated at 50° C in a water bath. An unlubricated condom filled with 50ml of blood, is fixed around each steel tube section and placed onto the screened tops of containers with triatomines. Nymphs and adults access the blood source by climbing a vertical piece of folded filter paper. After feeding, each condom can be easily and safely removed and discarded. This device consists of simple, cheap, safe and robust components that can be easily purchased, assembled and used. Contamination during or after feeding is practically excluded. The technique is successfully used in our Laboratory for almost two years.

New insights into the amphibious life of Biomphalaria glabrata and susceptibility of its egg masses to fungal infection.

The air-breathing snail Biomphalaria glabrata proliferates in stagnant freshwater, and nothing is known about the survival of eggs in intermittently (rather than perpetually) wet habitats. In the present study their egg masses matured, and juveniles subsequently eclosed and were mobile in a stable water film of transitory habitats simulated by two different simple test devices described here. The viability of eggs maintained in an unstable film however, was diminished. The maturation of egg masses in a water film or in water was significantly prevented by the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae. The efficiency depended on the fungal propagule and test environment. Hyphal bodies were more effective against egg masses than conidia. This appears to be a first report of activity of either entomopathogen against a mollusc. Both devices offer accurate and reproducible conditions to test both biological questions and the effects of substances or pathogens against B. glabrata egg masses in water films.