THE LIFE-CYCLE OF THE BONT TICK AMBLYOMMA-HEBRAEUM IN-VITRO

The life-cycle of the hard tick Amblyomma hebraeum was completed in vi tro by feeding all life-stages of the tick through silicone membranes on bovine blood from an abattoir. Ticks were placed in a simple feeder consisting of a honey jar containing the blood with a glass tube inse rt (o.d. 42 mm) across the end of which the membrane was stretched. Th is feeding unit was held in a water bath (38 degrees C). Larvae and ny mphs fed on a membrane (< 90 mu m thick) made of silicone reinforced w ith Kodak(R) lens cleaning paper, and adults on a silicone membrane (0 .5 mm thick) reinforced with Terylene(R) netting. To control microbial growth, gentamicin (5 mu g/ml) and nystatin (100 i.u./ml) were added to the weekly open-collected blood, which was manually defibrinated. T he blood was changed twice daily for nymphs and three times for adults and larvae. Attachment of ticks was induced with combinations of host hair, tick faeces, a bovine pelage extract and a synthetic aggregatio n-attachment pheromone mixture. The in vitro Life-cycle started with u nengorged ''natural'' adults, which had moulted from nymphs fed on ste er. The life-cycle closed with unengorged, first in vitro generation a dults which had moulted from nymphs fed in vitro. Although the feeding and development of larvae and nymphs were similar to in vivo controls , females fed and developed poorly in vitro. The toxicity of the syste mic acaricide Ivermectin(R) for nymphs of A. hebraeum was confirmed us ing the in vitro feeding method.