New Zealand Journal of Marine and Freshwater Research abstracts
Short communication
Stable isotope analysis identifies morphologically indistinguishable caddisflies
Michael J. Winterbourn
School of Biological Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
email: michael.winterbourn@canterbury.ac.nz
Abstract Stable nitrogen isotope values (δ15 N) were used to identify the morphologically indistinguishable adult females of Olinga feredayi and O. jeanae (Trichoptera: Conoesucidae), captured in Malaise traps at Cass, inland Canterbury, New Zealand. In the study area, larvae and pupae of the two species were abundant in two different streams and had distinct δ15 N values, presumably reflecting differences in the stable nitrogen ratios of organic materials assimilated by larvae. In contrast to δ15 N, stable carbon isotope values (δ13 C) were more variable and overlapped in the two species. Trapped adult females formed two discrete groups with δ15 N signatures that corresponded to those of larvae and pupae in the two streams and with those of adult males that can be identified using wing and genitalic characters. The successful identification of otherwise indistinguishable females depended on their larvae having habitat-specific isotopic signatures that were carried through into the adult stage. Successful identification will not always be possible, but where it is, otherwise unavailable information on the distribution, abundance and dispersal of the adults of aquatic insects can be obtained.
Keywords Trichoptera; Olinga; species discrimination; nitrogen stable isotopes; New Zealand; stream insects
New Zealand Journal of Marine and Freshwater Research, 2007, Vol. 41: 401–404
0028–8330/07/4104–0401 © The Royal Society of New Zealand 2007
M07050; Online publication date 28 November 2007
Received 10 October 2007; accepted 19 November 2007
PDF file of entire paper: Print-quality
(183K) | screen-quality (177K)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
