Variation in growth rate and reproductive output in British populations of the dorid nudibranch Adalaria proxima: consequences of restricted larval dispersal? |
| |
Authors: | W J Lambert C D Todd J P Thorpe |
| |
Institution: | (1) Gatty Marine Laboratory, School of Environmental and Evolutionary Biology, University of St. Andrews, St. Andrews, Fife, Scotland KY16 8LB, UK, GB;(2) Department of Biology, Wabash College, Crawfordsville, Indiana 47933 USA, IN;(3) Port Erin Marine Laboratory, University of Liverpool, Port Erin, Isle of Man IM9 6JA, UK, GB |
| |
Abstract: | Growth and reproduction were compared among six geographically and genetically distinct intertidal populations of the annual,
semelparous, dorid nudibranch Adalaria proxima (Alder & Hancock) to evaluate variation in fitness-related traits. The six populations spanned the geographic range in the
northern British Isles: NE England (Cowling Scar), E Scotland (Kinkell Braes), NW Scotland (Loch Eriboll), W Scotland (Cuan
Ferry), Northern Ireland (Portaferry), and N Wales (Menai Bridge). Nudibranchs from five sites were collected in July to August
1992 as post-metamorphic juveniles and were laboratory-reared under the same conditions of ambient temperature and photoperiod
for up to 10 months and the completion of spawning. Individuals from the sixth site were added to the experiment in December
1992. Growth was monitored every 2 weeks, and reproductive performance was expressed as a weight-adjusted dimensionless index
(ΣRI) of each individual's spawnings summed over the reproductive period. In general, larger nudibranchs produced larger first
spawn masses and more total spawn than did smaller nudibranchs, but these size-related trends were observed only in some populations.
The patterns of energy partitioning to spawnings varied significantly among populations, from allocations of a large number
of eggs to few spawn masses (Loch Eriboll) to production of many small spawnings over a long spawning period (Portaferry).
There was no relationship between maximum body size and the amount of spawn produced after the first spawning, nor to the
length of the spawning period or the number of spawn produced. Both Menai Bridge and Kinkell Braes had low mean population
ΣRI, reflecting a very poor reproductive performance, given their large maximum (pre-spawning) body sizes. By contrast, the Loch
Eriboll, Cuan Ferry, and Portaferry populations all displayed high mean population ΣRI, albeit as a result of differing combinations of numbers and sizes of spawn masses and duration of the spawning period. This
high variance of reproductive allocation among populations, and previous evidence of relatively stable among-population differences
in allozyme frequencies, adult color, and embryo characteristics suggest very restricted larval transport of lecithotrophic
larvae of A. proxima.
Received: 10 December 1998 / Accepted: 23 March 2000 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|