Revista Chilena de Historia Natural 83 (4): 593-603, 2010
RESEARCH ARTICLE
Temperature and foliage quality affect performance of the outbreak defoliator
Ormiscodes amphimone (F.) (Lepidoptera: Saturniidae) in northwestern Patagonia, Argentina
In the temperate forests of Chile and Argentina the phytophagous moth
Ormiscodes amphimone (F.) causes severe defoliation on the southern beech tree Nothofagus pumilio
(Poepp. & Endl.) Krasser. The recent increase in defoliation frequency in some areas appears to be influenced by a
warmer climate. To evaluate the effects of temperature and the spatial heterogeneity of foliage quality on the performance and relative
consumption rate of O. amphimone in northwestern Patagonia, Argentina we conducted a factorial
experiment. Larval performance was measured as relative growth rate, developmental time, larval survival, and pupal weight. Larvae of
O. amphimone were reared under two constant temperature regimes (15 °C and 20 °C) and fed with two N. pumilio
foliage types (from a mesic and from a xeric site). Larvae at the higher temperature and fed with leaves from the mesic site
showed higher performance and consumption rate than larvae in the other treatments. Higher temperature and mesic foliage had
positive effects on O. amphimone’s relative growth rate, development time and relative consumption rate. However, pupal
weight was positively influenced by mesic foliage but not by temperature, and larval survival did not show significant differences among
treatments. Our results preliminarily suggest that O. amphimone performance and consumption rate may
increase under higher temperature conditions, especially in the mesic portions of the precipitation gradient. However, these findings
should be carefully interpreted as further research is necessary to assess the influence of higher temperatures on the foliar quality of
N. pumilio.
Key words:
herbivory,
Nothofagus pumilio, outbreaks
