Agriculture Reference
In-Depth Information
Figure 8.3
. Summary of mean number of adults captured per weekly trapping interval for
nine ladybird beetle species within different systems of the MCSE over 18 years (1989-
2007). MCSE systems are described in Table 8.1.
Ostrom et al. (1997) used stable isotope techniques to show that the δ
13
C and
δ
15
N ratios of coccinellids track those of their food sources and from this inferred
patterns of coccinellid movement in the KBS landscape. In particular, they found
that 32 and 68% of the diet of
C. maculata
were derived from alfalfa and corn
pollen, respectively, which was consistent with the distribution of this species
during their study. Subsequently, Colunga-Garcia et al. (1997) showed that the
coccinellid community responded to overall landscape structure as measured
by habitat diversity and patchiness. In concordance with prior studies,
C. macu-
lata
was more abundant in a landscape that included corn, while
C. stigma
and
