La. Crawford et al., ACCUMULATION AND EGESTION OF DIETARY COPPER AND CADMIUM BY THE GRASSHOPPER LOCUST A MIGRATORIA R-AND-F (ORTHOPTERA, ACRIDIDAE), Environmental pollution, 92(3), 1996, pp. 241-246
Copper and cadmium budgets were studied for a model insect herbivore/h
ost plant system comprising the oligophagous leaf-chewing grasshopper
(Locusta migratoria) feeding on Zea mays (Gramineae). Fifth instar lar
vae were fed, for between 5 and 20 days, on maize foliage contaminated
with either copper, cadmium or on control foliage containing no exces
s metal. Male and female locusts fed on copper-treated maize retained
45 and 42% of ingested copper respectively, figures not significantly
different from the 41 and 33% retained on untreated maize. Remaining c
opper was egested with the faeces. Locusts fed on copper-treated maize
showed an increase of 27% in body copper burden compared with those o
n the control diet: the increase was independent of time on the diet.
Female locusts retained 33% and males 21% of ingested cadmium. Faecal
cadmium levels were elevated, and accumulation in both sexes was propo
rtional to time on the Cd-enriched diet. For both copper and cadmium,
some ingested metal probably passed directly through the locust gut, b
ound to undigested food material. Results suggest that grasshoppers ma
y effectively regulate excess dietary copper, but are unable efficient
ly to regulate cadmium. Copyright (C) 1996 Elsevier Science Ltd