Jr. Layne, WINTER MICROCLIMATE OF GOLDENROD SPHERICAL GALLS AND ITS EFFECTS ON THE GALL INHABITANT EUROSTA-SOLIDAGINIS (DIPTERA, TEPHRITIDAE), Journal of thermal biology, 18(3), 1993, pp. 125-130
1. The microclimate of spherical galls on goldenrod (Solidago) was mon
itored and the condition of goldenrod gallfly (Eurosta solidaginis) la
rvae also assessed during winter in western New York, U.S.A. 2. Gall t
emperature was highly labile and changed more than 20-degrees-C on som
e days. While galls closely followed air temperature at night, they of
ten warmed several degree-C above air temperature on sunny days. Gall
water content was even more labile, failing as low as 10% and rising a
bove 60% of the total mass during the observation period. 3. Larvae sh
owed little change in their body mass and hemolymph osmolality changed
moderately. Evidence of natural freezes was obtained but these did no
t last more than 2-3 days at a time. Natural hydration of galls caused
larvae to move from the central gall cavity into the exit tunnel and
restored the capacity of gall tissues to cause inoculative freezing. 4
. In summary, galls are highly labile environments that are greatly af
fected by the prevailing weather, however, Eurosta larvae seem adept a
t coping with these conditions.