CIBICIDES SPP (PROTOZOA, FORAMINIFERA) AS EPIZOITES ON THE ARCTIC ANTENNA-BROODING ARCTURUS-BAFFINI (CRUSTACEA, ISOPODA, VALVIFERA)

Cibicides spp. epizoites (Protozoa, Foraminifera) were studied on the arcturid Arcturus baffini (Crustacea, Isopoda, Valvifera), which carri es its juveniles on the long second antenna. The pattern of foraminife ran epibiosis changed during ontogenetic development, and was differen t for adult females and males. The first two developmental (manca) sta ges carried foraminifers mainly on their bodies, while on the third ma nca stage the foraminifers became more frequent on the long second ant enna. Settlement on the first two manca stages was mainly by fairly la rge, vagrant Cibicides refulgens probably arriving from the mother. Th e third manca stage individuals, however, gathered larvae mainly-from the water column and these settled on the inner side of the long secon d antenna. Foraminifers were also most frequent on the long second ant enna of the adults, which was probably most exposed to settling forami nifers. Adult females carried more foraminifers than males; brooding f emales had about 2.1 times more foraminifers on the second antenna tha n males of comparable size, but 3.7-4 times more foraminifers on their body and legs than the males. Foraminifers were somewhat larger on ad ult females than on adult males. This pattern may be related to somewh at longer time-spans available for settling on the females between mou lts. The different pattern of foraminiferan epibiosis between females and males may be due to migration of foraminifers from the females to juveniles carried on the second antenna.