Chemically induced plasticity in early life history of Palaemon argentinus : are chemical alarm cues conserved within palaemonid shrimps?

ITUARTE, ROMINA B.; VÁZQUEZ, MARÍA G.; BAS, CLAUDIA C.

JOURNAL OF EXPERIMENTAL BIOLOGY

COMPANY OF BIOLOGISTS LTD

Año: 2019 vol. 222

0022-0949

Most aquatic animals use infochemicals from both conspecifics andheterospecifics to assess local predation risks and enhance predatordetection. Released substances from injured conspecifics and otherspecies (chemical alarmcues) are reliable cues to indicate an imminentdanger in a specific habitat and often mediate the development ofinducible defenses. Amphibian and fish embryos have been shown toacquire this information while at the embryonic stage of development, inrelation to the developing nervous system and sensory development.With the exception of Daphnia, there is no information on chemicallymediated responses to alarm cues in embryos of any crustaceangroups. Therefore, we tested whether embryo exposure to chemicalcues simulating predation on conspecifics or heterospecifics (closelyrelated, non-coexisting species), or a mixture of both, alters embryonicdevelopmental time, size and morphology of the first larval instar inPalaemon argentinus (Crustacea: Decapoda). Embryonic exposure tochemical alarm cues from conspecifics shortened the embryonicdevelopmental time and elicited larger larvae with a longer rostrum.Rostrum length of the first larval instar changed independently of theirsize, thus elongated rostra can be considered a defensive feature.Embryonic developmental time was not altered by chemical alarmcuesfrom either heterospecifics or the mixed cues treatment; however,exposure to these cues resulted in larger larvae compared with thecontrol group. Chemically induced morphological plasticity in larvae inresponse to alarm cues from con- and heterospecifics suggests thatsuch cues are conserved in palaemonids shrimps, providing embryoswith an innate recognition of heterospecific alarm cues as predicted bythe phylogenetic relatedness hypothesis.