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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #305836
Title: Do counts of salivary sheath flanges predict food consumption in herbivorous stink bugs [Hemiptera: Pentatomidae]?

Author
item ZEILINGER, ADAM - University Of Minnesota
item Olson, Dawn
item RAYGOZA, TANIA - University Of California Agriculture And Natural Resources (UCANR)
item ANDOW, DAVID - University Of Minnesota

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2015
Publication Date: 1/30/2015
Citation: Zeilinger, A.R., Olson, D.M., Raygoza, T., Andow, D.A. 2015. Do counts of salivary sheath flanges predict food consumption in herbivorous stink bugs [Hemiptera: Pentatomidae]?. Annals of the Entomological Society of America. 108(2):109-116. doi: http://dx.doi.org/10.1093/aesa/sau011.

Interpretive Summary: Salivary sheaths have been widely used in studies of feeding behavior and crop damage of pestiferous stink bugs and other sheath-feeding Hemiptera. While salivary sheaths can effectively predict crop damage by stink bugs, previous studies have assumed that feeding behavior can also be inferred from salivary sheath data. Yet this assumption remains untested. We investigated the relationship between stink bug salivary sheaths and consumption of cotton bolls for two important agricultural pest species: Nezara viridula L. and Euschistus servus Say. We inferred food consumption rates from measures of relative growth rate and excreta quantity. To measure excreta, we quantified the color intensity, or chromaticity, of excreta using digital image analysis. We found a positive relationship between growth rate and salivary sheaths for 5th instars of E. servus. However, we found no relationship between our measures of consumption and the number of salivary sheaths for all stages of N. viridula and E. servus adults. Our results indicate that salivary sheaths should not be used to infer feeding activity or preference in studies on N. viridula and E. servus adults but can be used in studies of E. servus nymphs. This work adds to a growing body of literature on the diverse feeding styles among herbivorous stink bug species with potential implications on their abilities to cause crop damage.

Technical Abstract: For Pentatomid stink bug agricultural pests, the number of salivary sheaths and sheath flanges—the portion of the sheath visible on the exterior surface of a food item—are good predictors of the loss of crop yield or quality from stink bug feeding. As the often assumed relationship between salivary sheaths and food consumption has not been tested, we utilize growth rates and excreta quantity to test for relationships between these factors and the number of salivary sheaths. We quantified the color intensity, or chromaticity, of excreta using digital image analysis. Growth rates were determined by weighing nymphs and adult stink bugs at experiment initiation and after 3 days of feeding on cotton bolls. To aid in counting salivary sheaths on cotton bolls, an acid fuschin solution was applied to the external walls of the boll to stain the sheaths. We found a positive relationship between growth rate and salivary sheaths for 5th instars of E. servus, but found no relationship between our measures of consumption and the number of salivary sheaths for all stages of N. viridula and E. servus adults. Our results indicate that salivary sheaths should not be used to infer feeding activity or preference in studies on N. viridula and E. servus adults but can be used in studies of E. servus nymphs. Further work will be needed to understand whether our results for E. servus, with a positive relationship between growth rates and sheaths, or our results for N. viridula, with no relationship, is the more general case for Pentatomids and other sheath-feeding Hemiptera. Further work will also be needed to investigate potential effects of different host plants on the consumption-sheath relationship.