Premium
Effect of elevated atmospheric CO 2 on oviposition behavior in Manduca sexta moths
Author(s) -
Abrell Leif,
Guerenstein Pablo G.,
Mechaber Wendy L.,
Stange Gert,
Christensen Thomas A.,
Nakanishi Koji,
Hildebrand John G.
Publication year - 2005
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2005.00989.x
Subject(s) - manduca sexta , sphingidae , biology , foraging , nectar , carbon dioxide , manduca , ecology , zoology , botany , pollen , insect
Moths can detect changes in environmental carbon dioxide (CO 2 ) with extremely high sensitivity, but the role of CO 2 in the biology of these and other insects is not well understood. Although CO 2 has been demonstrated to influence egg‐laying (oviposition) behavior of the pyralid moth Cactoblastis cactorum and nectar foraging of the sphingid moth Manduca sexta , information about the generalized role of CO 2 in the behavioral biology of these species is lacking. Comparative data are necessary to properly assess how the behaviors of different species may be modified by steadily rising levels of greenhouse gases in the environment. Experiments carried out in Biosphere 2 addressed whether changes in ambient CO 2 levels play a role in the oviposition behaviors of M . sexta moths. In the first series of experiments, oviposition was measured inside a flight cage with different levels of nearly ambient or elevated CO 2 (400, 800 or 1200 ppm). For each concentration, hostplants used as oviposition sites were grown from seed at a CO 2 level that matched the environment inside the flight cage. Under homogenous levels of CO 2 , we observed no significant difference in oviposition behavior at the concentrations tested. In a second series of experiments, two groups of hostplants, each surrounded by a mini free‐air CO 2 enrichment (FACE) ring, were assembled inside a flight cage. In this choice test, a dynamic plume of artificially high CO 2 was generated around one group of test plants, while ambient CO 2 was released around the second (control) group. After eggs were counted on both plant groups, M. sexta females showed a small preference for ovipositing on the control plants. Therefore, in contrast to C. cactorum females tested under similar dynamic flow conditions, M. sexta female oviposition was not strongly inhibited by elevated CO 2 . To investigate this phenomenon further, we used electrophysiological recording and found that the CO 2 receptor cells in M. sexta , unlike those in C. cactorum , are not readily affected by elevated levels of ambient CO 2 . These findings therefore suggest that elevated background levels of CO 2 affect the physiology of the CO 2 detection system of M. sexta to a lesser extent than that of C. cactorum , and this correlates well with the observed differences in oviposition behavior between the two species under elevated levels of environmental CO 2 . Hostplants of C. cactorum are crassulacean acid metabolism plants that generate nocturnal CO 2 sinks on the cladode surfaces, whereas, M. sexta hostplants are nocturnal sources of respiratory CO 2 . We hypothesize that the abrupt and continuing increase in global ambient CO 2 levels will differentially alter the behavior and physiology of moths that use CO 2 sinks and sources as sensory cues to find hostplants.