Biology Reference
In-Depth Information
each from Puerto Rico, Texas, and Mississippi in an effort to understand migra-
tion of the moth. This is of increasing importance to pest managers because
populations in Puerto Rico are resistant to Cry toxins from
Bacillus thuringiensis
in
transgenic corn. If the fall armyworm is not controlled, it can reduce corn yields
by up to 73% (
Arias et al. 2011
). Currently, control relies on applications of pes-
ticides timed to kill young larvae. Because Puerto Rico is only 1500 km from the
United States, movement of resistant moths into the United States is possible.
Arias et al. (2011)
evaluated species-specific microsatellites as more-sensitive
markers for population genetic analyses of the fall armyworm and conducted
cluster analysis using 120 markers to calculate genetic distances among the pop-
ulations sampled. These markers could become “an effective tool for population
studies by using multiple loci to help better understand migrations and possible
crosses of this insect.”
Lewter and Szalanski (2007)
developed a PCR-RFLP method for analyzing
a 611-bp region of the COI-COII genes of the mitochondrion to discriminate
between seven noctuid species, including the fall armyworm, collected in phero-
mone traps in Arkansas. Moths found in the traps often are difficult to diagnose
to species but the PCR-RFLP method allowed species diagnoses to be obtained
within 1 day.
13.7.2 Analyses of Natural Enemies
Understanding the biology, behavior, and ecology of natural enemies should
allow pest managers to improve their use in pest-management programs.
Information on the hosts or prey of many natural enemies is limited. Monitoring
natural enemies in the field after releases in classical biological control programs
can be expensive and difficult. Molecular analyses are being developed to learn
more about host or prey ranges, as described in the upcoming sections, and for
monitoring establishment and spread after release.
13.7.2.1 Analyses of Adult Parasitoid Wasps to Reveal Larval Hosts (MAPL)
Females of a hymenopteran or dipteran parasitoid species deposit eggs or lar-
vae in or near a host. The immature parasitoid then devours the host, leaving
it as an adult to locate another host. Many parasitoids have unknown life his-
tories, but many adult parasitoids can be collected even if their larval hosts are
unknown (
Rougerie et al. 2011
).
Rougerie et al. (2011)
were able to sequence a
diagnostic DNA marker (a COI DNA barcode sequence) from 24% of 297 adult
parasitoids that allowed them to identify the host used by the wasps during
their larval stages. They called this method M
olecular
A
nalysis of
P
arasitoid
L
inkages
or
MAPL
. Their results indicated that larval-host DNA can persist
