GROOMING BEHAVIOR AND ASSOCIATED STRUCTURES OF THE MYSID MYSIDOPSIS-BAHIA

Grooming behavior as an antifouling mechanism is documented for the first time in a mysid crustacean. Behavioral observations and a scanning electron microscope (SEM) survey of the setae reveal that Mysidopsis bahia uses specialized setae to remove fouling epizoites and particulates from vital areas of the body. Various combinations of appendages are used in different grooming activities. The mandibular palps are highly modified for brushing the antennae. The second thoracic endopod is the most active appendage functioning in grooming the antennae, setae of the marsupium, and other thoracic appendages. The third through eighth thoracic endopods are slender, flexible, and have long comblike setae that are used to dean the natatory exopods and other structures. Quantitative observations show that more grooming activity is focused on the antennules than on the antennae. Cleaning of the telson and outer marsupial walls was also observed. Although young mysids possess all appendages when released from the marsupium, the appendages of newly emerged M. bahia lack important setal types and numbers necessary for effective grooming. The juveniles appear to be dependent on ecdysis associated with growth to counter fouling. A comparison of fouling between adults and juveniles held in turbid water confirms the effectiveness of grooming behavior and associated structures.