The Effect of Temperature on Feeding, Digestion, and Absorption of Lytechinus Variegatus (Lamarck) (Echinodermata, Echinoidea)

Lytechinus variegatus were collected from 25 C waters, maintained in the laboratory for 4 wk at either 16 or 23 C, and fed an artificial food. Feeding rates of individuals maintained at 16 C were low initially but subsequently increased to rates near those of individuals maintained at 23 C. Passage times of food through the gut decreased after 4 wk at 16 C but remained longer than those observed at 23 C. Activities of digestive carbohydrases were similar and low in both groups when measured at 16 C and showed a Q ₁₀ of ca. 2 in the range of 16-25 C. Absorption efficiencies and amounts of organic material absorbed from food were consistently lower for individuals maintained at 16 C than for those at 23 C. Although feeding rates compensate, L. variegatus is less efficient at processing food at 16 C than at 23 C.