Interference interactions among tube-dwelling polychaetes in a dense infaunal assemblage

Levin, LA.  1982.  Interference interactions among tube-dwelling polychaetes in a dense infaunal assemblage. Journal of Experimental Marine Biology and Ecology. 65:107-119.


Interactions involving contact between the feeding organs of the tube building polychaetes Pseudopolydora paucibranchiata Okuda, Streblospio benedicti Webster, and Fabricia limnicola Hartman were observed through a dissecting microscope and quantified for frequency of occurrence and effects on foraging time and withdrawal. These surface feeding species form a dense intertidal assemblage ( > 100000 individuals · m−2) and can be readily transferred to the laboratory and observed in undisturbed sediment cores. Interspecific contact with Pseudopolydora often resulted in withdrawal and consequently a 4 to 7% loss of foraging time for individuals of other species, while intraspecific interactions among Pseudopolydora did so rarely. Larger individuals of all three species experience more interaction. The probability and duration of withdrawal due to contact with Pseudopolydora is size dependent in Fabricia and Streblospio: juvenile Fabricia and adult Streblospio show the greatest interference. The observation that Pseudopolydora interferes with individuals of other species more than with conspecifics contradicts the small-scale dispersion of these species as well as previous reports of interference behavior. A possible explanation is the relatively recent coexistence of these three species, two of which were introduced to the eastern Pacific since 1900.