Diversidad y control biológico de insectos - CyberTesis UACh ...

N is the total number of individuals and Ni the number of individuals in the i th species. The
abundance levels for simulation were fixed according to the treatment with lowest
abundance to allow comparison between treatments.
Dominance.
Dominance (fraction of the total catches represented by the most abundant species) was
calculated using species diversity module of ECOSIM and 95% confidence intervals were
obtained as described above.
Results
Taxonomic and functional identity.
A total of 9555 invertebrates were identified in both experiments. Five taxa accounted for
84% of the total captures: Cantharidae (34%), Acari (30%), Curculionidae (9%), Carabidae
(7%) and Araneae (4%). The functional groups represented were herbivores (50%),
detritivores (34%), predators (14%) and omnivores (2%). An overview of the community
composition is given in Tables 1-5 (anexo 3).
Effects on community metrics.
Diversity.
The diversity changes on winter experiment are shown in Figure 3 (left). Before treatment,
diversity at the control site (expressed by Shannon index) was higher than both B. bassiana
and λ-cyhalothrin sites, while no significant differences were observed between these
treated sites (Figure 3, left). Twenty days after a single spraying of B. bassiana QU-B931
or λ-cyhalothrin, control and B. bassiana sites showed no differences (α = 0.05), while the
diversity was significantly lower in the λ-cyhalothrin site (Figure 3, left). The same result
was observed 40 days after spraying.
The diversity changes in the spring experiment are shown in Figure 4 (top). Samples taken
before spraying indicated that diversity in untreated and treated sites was similar. Thirty
days after spraying, estimates of Shannon index showed no differences between control and
B. bassiana sites, while diversity at λ-cyhalothrin site was significantly lower than both
control and B. bassiana sites.
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