1987] 
Windsor — Tortoise beetle, Acromis sparsa 
133 
Females were able to rapidly replace a missing egg mass. Egg 
masses were removed from eighteen guarding females during the 
last week of May 1984. Nine of these females were discovered 
nearby on new egg masses the following week. The difference in the 
average number of eggs in original and replacement egg masses, 37.4 
and 35.5 respectively, was not significant (Mann- Whitney U test, 
U = 38, p > 0.05). 
Egg parasitoids and hatching success 
Mothers frequently moved in a jerky manner on or near their egg 
mass when parasitic Hymenoptera (unidentified Eulophidae) were 
present. Wasps normally landed on the undersurface of a leaf 2-4 
cm away and oriented toward the eggmass (Fig. la). From this 
position they darted directly to the eggmass to oviposit. Movements 
by the wasps on the leaf appeared to stimulate A. sparsa females to 
rapidly move back and forth and around the eggmass for short 
periods of time. Wasps were also observed resting on the elytra of 
brooding females, females without offspring and occasionally on 
males. Carroll (1978) mentioned similar phoresy by a eulophid wasp 
on a Brazilian cassidine beetle, Stolas sp.. 
To assess the importance of egg parasitoids, a total of 103 aban- 
doned egg masses were collected from three habitats between late 
August and early November 1978 and examined egg by egg for the 
small exit hole of an emerging wasp or the larger serrated opening of 
an A. sparsa larva. These eggs, numbering 3893, produced 1004 
wasps (26%) and 2342 larvae (60%). Five hundred and forty-seven 
eggs (14%) failed to develop. Significant differences existed between 
habitats in the number of wasps and the number of undeveloped 
eggs per egg mass (Table 2). The median number of wasps emerging 
from egg masses was greatest at the “field” site, least at the “forest” 
site and intermediate at the “mixed” site. The median number of 
undeveloped eggs was also much higher at the “field” site than either 
of the other two sites. Thus, A. sparsa females were most successful 
in producing larvae at the “forest” site, intermediately successful at 
the “mixed” site and least successful at the “field” site. It is unclear 
why some eggs fail to hatch. That undeveloped eggs are more 
common where egg parasitoids are more abundant suggests that 
multiple ovipositions by parasitoids might be responsible. Physical 
conditions, especially maximum daytime temperature and humid- 
ity, also differ between shaded and open sites. 
