The effect of Blastocrithidia triatomae (Trypanosomatidae) on the reduviid bug Triatoma infestans: influence of group size.
Developmental time and mortality in uninfected larvae of the reduviid bug Triatoma infestans and in those infected by feeding a mixture of blood and cysts of the homoxenous trypanosomatid Blastocrithidia triatomae were compared. Larvae were maintained isolated in 77-cm3 (area 9.6 cm2) beakers or in groups of 20, 30, 40, and 50 bugs per 1-liter beaker (area 722 cm2). In uninfected groups, only a minor proportion of isolated bugs showed delayed development, but in groups infected with B. triatomae, additionally, a retardation in groups of 50 larvae occurred. Infected bugs needed more time to complete development in fourth and fifth instar than did uninfected bugs. Mean mortality rates of about 10% in uninfected groups were unaffected by group size. Mortality rates in most groups of infected bugs were about 50%, but in groups consisting of 50 larvae a statistically significant higher mortality rate of 75% was observed. This indicates a subpathological overcrowding stress, increased by the synergistic action of the flagellate.
Schaub
G A
GA
Institut für Biologie I (Zoologie), Albert-Ludwigs-Universität, Freiburg, Federal Republic of Germany.
D000818:Animals; D007303:Insect Vectors; D007814:Larva / Q000254:growth & development / Q000469:parasitology; D014224:Triatoma / Q000254:growth & development / Q000469:parasitology*; D014351:Trypanosomatina / Q000472:pathogenicity*