Employing immunomarkers to track dispersal and trophic relationships of a piercing-sucking predator, Podisus maculiventris (Hemiptera: Pentatomidae)

Immunoproteins are markers that are useful for monitoring dispersal and/or pest consumption, but current application techniques are less effective for the large guild of piercing-sucking predators important in biocontrol. We quantified the use of protein immunomarks in tracking emigration of spined soldier bug, Podisus maculiventris Say (Hemiptera: Pentatomidae) and predation on the hornworm caterpillar, Manduca sexta L. (Lepidoptera: Sphingidae). An external protein mark was topically applied to adult P. maculiventris to assess persistence under field conditions for >2 weeks. Internal marks were incorporated into the artificial diet of M. sexta to test retention of the internal mark in the prey and uptake of the mark by predators. External marks remained detectable in 100% of individuals after three days and >50% still tested positive at 12 days after application in the field. Internal diet-based marking was also effective in tracking feeding by P. maculiventris on M. sexta, especially using rabbit IgG which was far more persistent than chicken IgY. Nearly 90% of stink bugs fed caterpillars previously reared on protein-enriched diet retained their mark for 24 hours. Surprisingly, diet concentration and time reared on diet had comparatively little impact on mark retention. Development on unmarked tomato leaves clearly diluted the initial diet mark, but plant-reared individuals that were marked were still successfully detected in 35% and 20% of the predators.