The opening-closing rhythms of the subelytral cavity associated with gas exchange patterns in diapausing Colorado potato beetle, Leptinotarsa decemlineata.
The opening-closing rhythms of the subelytral cavity and associated gas exchange patterns were monitored in diapausing Leptinotarsa decemlineata beetles. Measurements were made by means of a flow-through CO2analyser and a coulometric respirometer. Under the elytra of these beetles there is a more or less tightly enclosed space, the subelytral cavity (SEC). When the cavity was tightly closed, air pressure inside was sub-atmospheric, as a result of oxygen uptake into the tracheae by the beetle. In about half of the beetles, regular opening-closing rhythms of the SEC were observed visually and also recorded; these beetles displayed a discontinuous gas exchange pattern. The SEC opened at the start of the CO2burst and was immediately closed. On opening, a rapid passive suction inflow of atmospheric air into the SEC occurred, recorded coulometrically as a sharp upward peak. As the CO2burst lasted beyond the closure of the SEC, we suggest that most of the CO2was expelled through the mesothoracic spiracles. In the remaining beetles, the SEC was continually semi-open, and cyclic gas exchange was exhibited. The locking mechanisms and structures between the elytra and between the elytra and the body were examined under a stereomicroscope and by means of microphotography. We conclude that at least some of the L. decemlineata diapausing beetles were able to close their subelytral cavity tightly, and that the cavity then served as a water-saving device.
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Aare
A
Kuusik
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia katrin.jogar@emu.ee.
Katrin
0000-0002-2330-1995
K
Jõgar
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Luule
L
Metspalu
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Angela
A
Ploomi
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Enno
E
Merivee
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Anne
A
Must
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Ingrid H
IH
Williams
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Külli
K
Hiiesaar
Department of Silviculture, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia.
Ivar
I
Sibul
Department of Plant Protection, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Marika
M
Mänd
D000375:Aging / Q000502:physiology; D000818:Animals; D001517:Coleoptera / Q000033:anatomy & histology* / Q000502:physiology*; D064666:Diapause, Insect / Q000502:physiology*; D005740:Gases / Q000378:metabolism*; D012212:Rheology; D011198:Solanum tuberosum / Q000469:parasitology*
D005740:Gases
Cyclic gas exchange; Discontinous gas exchange; Respiration; Water loss rate