Non-random distribution patterns of leaf miners on oak trees.

Area of Science:

• Ecology
• Entomology
• Plant-Insect Interactions

Background:

• Leaf-mining insects, such as Stilbosis quadricustatella, exhibit non-random spatial distribution patterns within host plant leaves.
• Understanding these patterns is crucial for comprehending population dynamics and mortality factors.

Purpose of the Study:

• To investigate the spatial distribution of Stilbosis quadricustatella larvae on sand live oak (Quercus geminata) and water oak (Q. nigra).
• To identify the mortality factors influencing leaf-miner survival based on their distribution within leaves.

Main Methods:

• Field observations of leaf-miner distribution on host plants in north Florida.
• Analysis of mortality factors including competition, parasitism, and predation.
• Comparison of mortality rates between larvae clustered on one leaf side versus those separated by the mid-vein.

Main Results:

• Larvae distribution was non-random, with fewer mines clustered on the same side of the mid-vein compared to opposite sides.
• No significant differences in competition, parasitism, or predation were found between clustered and separated larvae.
• Early leaf abscission occurred significantly more frequently in leaves with clustered larvae, leading to higher mortality.

Conclusions:

• Larval clustering on one side of the mid-vein increases mortality risk for Stilbosis quadricustatella due to premature leaf abscission.
• The precise mechanisms driving differential leaf abscission remain undetermined.
• Spatial distribution significantly influences the survival of leaf-mining insect populations.