The use of artificial sponges as breeding habitat by Paracerceis sculpta (Holmes) (Crustacea:Isopoda)

Abstract

Artificial cavities constructed of a synthetic polymer, FHP-3000, were used as substitutes for calcareous sponges [ Leucetta losangelensis (de Laubenfels)] normally used as reproductive habitat by Paracerceis sculpta (Holmes), a Gulf of California isopod crustacean. This paper demonstrates that: 1. (1) artificial sponges adequately simulate natural sponges under laboratory conditions; 2. (2) α-males in this species colonize spongocoels more readily than sexually receptive females; 3. (3) isopods do not discriminate between artificial sponges containing and not containing a suspension of natural sponges; i.e., isopods may use cues other than waterborne chemicals produced by sponges to locate reproductive habitat; 4. (4) α-males that have already occupied artificial sponges do not appear to recolonize artificial sponges more readily than naive α-males; 5. (5) neither sexually receptive nor gravid (nonreceptive) females tend to form aggregations within spongocoels in the absence of α-males; and 6. (6) α-males discriminate osculum diameter when colonizing spongocoels i.e., they prefer oscula most closely matching their own body diameter, but do not discriminate sponge complexity or spongocoel volume. These results indicate that artificial sponges provide functional substitutes for this crustacean's natural reproductive habitat, and may facilitate experiments usually prevented for species that inhabit living substrata such as sponges or tunicates.