Detrimental effects of the isopod, <Emphasis Type="Italic">Edotia doellojuradoi,</Emphasis> on gill morphology and host condition of the mussel, <Emphasis Type="Italic">Mytilus edulis platensis</Emphasis> |
| |
Authors: | Héctor E Zaixso Paula Stoyanoff Damián G Gil |
| |
Institution: | 1.Instituto de Desarrollo Costero,Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), Ciudad Universitaria,Km 4 (9000) Comodoro Rivadavia,Chubut,Argentina;2.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Buenos Aires,Argentina;3.Departamento de Gestión Ambiental,FHyCS, UNPSJB,Chubut,Argentina;4.Departamento de Biología General,FCN, UNPSJB,Chubut,Argentina |
| |
Abstract: | There are many reported associations between mussels and other invertebrates, such as pea crabs, polychaetes, turbellarians
and copepods, which live in their mantle cavities. The boundary between commensalism and parasitism is often indistinguishable
because of insufficient knowledge or because the interaction is variable. Preliminary evidence led to a closer examination
of the relationship between the mussel, Mytilus edulis platensis, and an isopod, Edotia doellojuradoi, previously described as commensalism. Monthly intertidal samples of mussels were taken from September 2004 to August 2005
at Caleta Cordova Norte (45°43′S, 67°22′W) in southern Argentina and assessed for the prevalence and abundance levels of isopods.
Mussels with and without isopods were measured, examined for evidence of gill damage and their condition (soft tissue dry
weight) was determined. The overall isopod prevalence in mussels was 57.9% and infestation varied with mussel length, with
maximum occurence at 30.2 mm (medium-sized mussels). Experimental evidence indicated that the position of the isopod inside
the mussel depended on the feeding activity of the mussel. Female isopods were observed grasping the ventral food groove of
the gill demibranchs and feeding on the mucous food strand produced by the mussel. Juveniles and males were observed clustered
together on the dorsal side of the single female in each occupied mussel, suggesting extended maternal care. Gill damage was
observed in 58.2% of mussels at the Argentine site and was significantly associated with isopod occurrence. Categorical regression
analysis showed that the most important factor associated with the degree of gill lesions was the number of male and juvenile
isopods per mussel, followed by the length of female isopods and the developmental stage of juveniles. Conversely, the degree
of gill damage decreased with increasing mussel length. Overall, E. doellojuradoi had a significant effect on mussel condition throughout the year, with low flesh weight in mussels with isopods, except during
the austral summer and early autumn. In contrast to previous studies, which concluded that the isopod was a commensal, the
present study clearly demonstrates that E. doellojuradoi is a parasite of M. edulis platensis. Other symbiotic interactions formerly classified as commensal might not be innocuous on further investigation, especially
if samples are taken at multiple sites and at different times of the year. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|