DENSITY-DEPENDENT FACTORS REGULATING FEEDING SUCCESS OF IXODES-SCAPULARIS LARVAE (ACARI, IXODIDAE)

We studied the effects of different parasite and host densities on the feeding success of larval Ixodes scapularis ticks upon white-footed m ice Peromyscus leucopus. Mice were infested daily with 10, 25, 50, or 100 larvae and kept individually or in groups of 2 and 3 to simulate c o-nesting in the field. Engorgement weight and molting success of repl ete larvae did not change during more than 3 wk of continuous infestat ion, but overall larval feeding success decreased from 24% to 12% with increased infestation density. Grooming was observed in response to u nattached, crawling larvae, and grooming of unfed ticks increased with infestation density. Nearly all larvae completed engorgement once att ached, although a few were groomed accidentally along with unattached ticks. Go-nesting mice fed 2-3 times fewer ticks than did solitary mic e because of increased frequency of self-grooming in the presence of n est-mates, but differences between groups of 2 or 3 mice were not sign ificant. Thus, increased mouse density may reduce the density of the t ick population at first, but further increase in the number of co-nest ing mice does not affect the feeding success of larval I. scapularis a nd increased mouse density will increase tick density.