Influence of salinity, diurnal rhythm and daylength on feeding in Laternula marilina Reeve |
| |
| Authors: | Shuhong Zhuang |
| |
| Institution: | Biological Science and Chemical Engineering School, Yantai University, Shandong Province, China |
| |
| Abstract: | A nature‐simulating culture system was used to explore the influence of salinity, the diurnal cycle and daylength on ingestion rate (IR) and assimilation efficiency (AE) of Laternula marilina. The clams used in the experiments were grouped into three sizes: large, medium and small according to shell length and dry fresh weight. The clams in all size groups demonstrated a common response pattern in IR and AE under salinities ranging from 18 to 34 g L?1. The clams achieved the greatest IR within the salinity range 27–30 g L?1. There was a marked reduction in IR outside this range. Of the salinities tested 18 g L?1 was the harshest stress to the feeding of L. marilina. Between the salinities of 24 and 34 g L?1, the AE of the clam responded in an inverse way to that of IR, suggesting that L. marilina is able to compensate for the loss of IR by an increase in AE. Although the differences between clam size groups were not statistically different, those between different salinities were except those between 27 and 34 g L?1 (IR) and 23 and 34 g L?1 (AE). All sizes of clam showed a two‐phase diurnal feeding pattern, a high ingestion phase from 00:00 to 08:00 hours and a low ingestion phase from 12:00 to 20:00 hours. The response of feeding (as measured by IR) to daylength comprised high and constant feeding at daylengths from 0 to 16 h and declining and unstable feeding as daylength increased from 16 to 24 h. All sizes of clams demonstrated an inverse adaptation to AE compared with IR, indicating that the clam is able to achieve a stable feeding physiology by compensating for daylength‐induced variations in IR by changing AE. |
| |
| Keywords: | Laternula marilina ingestion rate assimilation efficiency salinity diurnal cycle daylength |
|
|
