Science for University Students. Part II. Translations. Сологуб Л.И. - 6 стр.

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IN CLASS ACTIVITIES
Section I
Text 1
Mosquito Survival
Relations among parasites and their hosts (cover) are not simple to predict;
many environmental factors come into play and affect the survival equation. For
example, Aedes sierrensis mosquitos are subject to fatal parasitic infections by
the protozoan Lambornella clarki, but under some conditions, notably limited
food supplies, populations with infections can actually produce more and in
some cases larger adult mosquitos than do populations that are uninfected. This
surprising outcome was observed by Washburn et al. who compared survival
and fitness of adults that developed from infected and uninfected mosquito
populations in both laboratory and manipulated field settings. When the
mosquitos developed with an adequate food supply, individuals from uninfected
populations survived the best. When food was scarce, not only were survivors
from infected populations more fit but they were as or more abundant than
survivors from uninfected populations. The fatal infections in the population
apparently worked to increase the per capita food supply. Effective biological
control of mosquitos, therefore, will have to take into account how resource
availability and other environmental parameters work to shift the balance in
host-parasite relations.
Ruth Levy Guyer
I. Read the text - summary and state what information it carries.
II. Choose the correct answer
1. The main idea of the text is that:
a. uninfected populations survive the best
b. an adequate food supply always effects population survival
c. survivors from infected population are less fit
d. when food is scarce survivors from infected populations are abundant
2) The text suggests that:
a. the per capita food supply increased when populations were uninfected
b. the per capita supply increased when populations were infected
c. the per capita food supply increased when food was adequate
d. the per capita food supply increased when food was scarce
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