Science, Vol 253, Issue 5016, 185-188
Copyright © 1991 by American Association for the Advancement of Science
Regulatory role of parasites: impact on host population shifts with resource availability
JO Washburn,
DR Mercer,
and
Anderson JR
Department of Entomology, University of California, Berkeley 94720.
Effects of infections by the ciliate Lambornella clarki on larval populations of its mosquito host Aedes sierrensis were examined in laboratory and field studies. When host populations developed with sufficient food, mortality from parasites was additive and reduced the number of emerging mosquitoes. For food-limited populations, mortality was compensatory or depensatory; emerging adults were as or more abundant with higher average fitness than those from uninfected control populations. When nutrients were scarce, parasitic infections relaxed larval competition and increased per capita food by reducing host abundance. Food limitation altered larval feeding behavior, reducing horizontal transmission and subsequent mortality from parasitism.
