Chemical signal mediated premating reproductive isolation in a marine polychaete, Neanthes acuminata (arenaceodentata).

Neanthes acuminata Ehlers (1868) is a monogamous coastal polychaete with male parental care and a high level of sexual selection. We measured the level of prezygotic isolation among allopatric populations of N. acuminata; from the East and West Coast of the USA, a population from Hawaii, and a laboratory culture originating from Los Angeles, CA. All populations were found to preferably mate with members of their own population. Individuals from populations from Atlantic vs. Pacific Ocean failed to pair and to mate, either during the 10 min or 48 hr experiments. Instead, individuals showed high levels of aggressive behavior. Experiments measuring the levels of interpopulation aggression, established that individuals can recognize and discriminate among different populations of N. acuminata on the basis of olfactory cues. Aggressive behavior was induced by exposure of animals to seawater "conditioned" by individuals from the other populations, thus demonstrating the role of olfaction in the detection of "home" populations. The aggressive display was stronger upon exposure to seawater conditioned with "unrelated" populations and especially between Pacific and Atlantic populations.

[Use of three species of crustacea as test animals for the toxicity of two salts of heavy metals]. / Utilisation de trois espèces de Crustacés comme animaux tests de la toxicité de deux sels de métaux lourds

The utilization of marine amphipods Podocerus fulanus and Corophium acherusicum, and the marine isopod Paracerceis sculpta in heavy metal toxicity tests (Cd and Cu) demonstrated on the one hand, the value of these animals as tests subjects when exposed to various polluting agents and, on the other hand their tolerance to heavy metals in acute toxicity tests.