Studies on gas exchange in the meadow spittlebug, Philaenus spumarius: the metabolic cost of feeding on, and living in, xylem sap.
J Exp Biol
; 222(Pt 3)2019 02 11.
Article
en En
| MEDLINE
| ID: mdl-30745324
ABSTRACT
Spittlebugs (superfamily Cercopoidea) live within a mass of frothy, spittle-like foam that is produced as a by-product of their xylem-feeding habits. The wet spittle represents a unique respiratory environment for an insect, potentially acting either as a reserve of trapped oxygen (O2) or as a significant barrier to O2 diffusion from the surrounding atmosphere. Feeding on xylem sap under tension is also assumed to be energetically expensive, potentially placing further constraints on their gas exchange. To understand the respiratory strategies used by spittlebugs, this study measured the PO2 within the spittle of the meadow spittlebug, Philaenus spumarius, as well as the non-feeding metabolic rate (RMR) and respiratory quotient (RQ) of both nymphs and adults. The metabolic rate of nymphs feeding on xylem was also measured. In separate experiments, the ability of a nymph to obtain O2 from bubbles while submerged in foam was determined using a glass microscope slide coated in an O2-sensitive fluorophore. We determined that P. spumarius breathes atmospheric O2 by extending the tip of its abdomen outside of its spittle, rather than respiring the O2 trapped in air bubbles within the foam. However, spittlebugs can temporarily use these air bubbles to breathe when forcibly submerged. VÌO2 and VÌCO2 did not differ statistically within life stages, giving a RQ of 0.92 for nymphs and 0.95 for adults. Feeding on xylem was found to increase the nymphs' VÌCO2 by only 20% above their RMR. From this cost of feeding, cibarial pump pressures were estimated to be between -0.05 and -0.26â
MPa.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Herbivoria
/
Hemípteros
Tipo de estudio:
Health_economic_evaluation
Límite:
Animals
Idioma:
En
Revista:
J Exp Biol
Año:
2019
Tipo del documento:
Article
País de afiliación:
Canadá