  Invasion by the red imported fire ant, Solenopsis invicta Buren, has
destructive effects on native biodiversity, agriculture, and public health.
This ant's aggressive foraging behaviour and high reproductive capability have
enabled its establishment of wild populations in most regions into which it has
been imported. An important aspect of eradication is thorough nest monitoring
and destruction during early invasion to prevent range expansion. The question
is: How intense must monitoring be on temporal and spatial scales to eradicate
the fire ant? Assuming that the ant was introduced into a region and that
monitoring was conducted immediately after nest detection in an effort to
detect all other potentially established nests, we developed a mathematical
model to investigate detection rates. Setting the monitoring limit to three
years, the detection rate was maximized when monitoring was conducted shifting
bait trap locations and setting them at intervals of 30 m for each monitoring.
Monitoring should be conducted in a radius of at least 4 km around the source
nest, or wider --depending on how late a nest is found. For ease of
application, we also derived equations for finding the minimum bait interval
required in an arbitrary ant species for thorough monitoring.
