title: Caterpillar guts and ammonia volatilization: retention of nitrogen by gypsy moth larvae consuming oak foliage.
abstract: The gypsy moth (Lymantria dispar L.), a major defoliator of hardwood forests in the eastern U.S., has a highly alkaline midgut pH. We hypothesized that the high pH would cause high rates of ammonia (NH3) volatilization as larvae consumed foliage, leading to potentially large losses of N from the ecosystem to the atmosphere during gypsy moth outbreaks. We measured NH3emission during the consumption of oak foliage by larvae in the laboratory. Surprisingly, we found very low amounts of NH3release of about 0.1% of the N consumed in foliage. We speculate that digestive mechanisms may limit NH3production in the midgut, and that the acidic environment of the hindgut traps most of the small amount of NH3that is produced, effectively preventing a potentially very large N loss from both larvae and ecosystem. The estimated rate of NH3emission from a defoliated forest is small compared to other inputs and outputs of N from the ecosystem, but could potentially enhance the neutralization of atmospheric acidity during the defoliation period.
authors.affiliation: Institute of Ecosystem Studies, Millbrook, NY 12545, USA e-mail: LovettG@ecostudies.org, Tel.: +1-914-6775343, Fax: +1-914-6775976, , , , , , US.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Lovett
authors.affiliation: Institute of Ecosystem Studies, Millbrook, NY 12545, USA e-mail: LovettG@ecostudies.org, Tel.: +1-914-6775343, Fax: +1-914-6775976, , , , , , US.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Hart
authors.affiliation: Institute of Ecosystem Studies, Millbrook, NY 12545, USA e-mail: LovettG@ecostudies.org, Tel.: +1-914-6775343, Fax: +1-914-6775976, , , , , , US.
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Christenson
authors.affiliation: Institute of Ecosystem Studies, Millbrook, NY 12545, USA e-mail: LovettG@ecostudies.org, Tel.: +1-914-6775343, Fax: +1-914-6775976, , , , , , US.
authors.forename: Clive G
authors.initials: CG
authors.lastname: Jones
keywords: Defoliation; Gypsy moth; Key words Ammonia emission; Lymantria dispar; Nitrogen cycling