Contributions of larval biology to crustacean research: a review

Abstract

SummaryMany aquatic crustaceans pass through a complex life cycle comprising a benthic juvenile-adult and a pelagic larval phase. In the study of aquatic ecology, meroplanktonic larvae are therefore considered as principal components of benthic-pelagic coupling processes. As a consequence of radical transitions of life style, larvae differ from conspecific adults in their ecology, behaviour, nutrition, morphology, and physiology. Ontogenetic changes of these traits, as well as carry-over effects of larval condition on postmetamorphic fitness of benthic juveniles, are subjects of the interdisciplinary field of larval biology. Larval biology is thus not only an intrinsic part of lifehistory studies, but contributes essential information also to various other biological disciplines, including the broad area of crustacean research. For economically important species, it provides critical information for the development of aquaculture techniques or for the management of sustainable fisheries. Inferring from heritable ontogenetic patterns, comparative studies of larval morphology also aid the identification of phylogenetic relationships within and among higher taxa ("Evo-Devo" perspective). On the other hand, larval traits may be modified by environmental factors, which link larval ecology to developmental biology ("Eco-Devo" approach). Patterns of larval dispersal, mortality, and recruitment are crucial for the stability of benthic populations and communities. These aspects of "supply-side ecology" have also consequences for patterns of biogeographic distribution, population connectivity, genetic diversity, and the formation of metapopulations. In addition, the spread of introduced species in recipient regions may be explained or predicted through developmental and ecophysiological traits of their larvae. In evolutionary biology, knowledge of reproductive and developmental adaptations is crucial for the understanding of limnic and terrestrial invasions by originally marine crustaceans.

From lecithotrophy to planktotrophy: ontogeny of larval feeding in the Amazon River prawn Macrobrachium amazonicum

“…During the downstream transport with river currents, the early larval stages are exposed to food limitation due to typically low or unpredictable mesozooplankton production in lotic freshwater habitats with short residence times (Pedrosa et al 1999, Akopian et al 2002. This nutritional stress selects for an enhanced maternal energy investment into egg production, allowing a partially food-independent early larval development (Anger 2001(Anger , 2006. In M. amazonicum, the functional morphology of larval mouth parts (Odinetz Collart & Magalhães 1994), as well as behavioural observations (Araujo & Valenti 2007), suggest that Zoea I is most probably a non-feeding stage.…”

Larval development of the subantarctic squat lobster Munida subrugosa (White, 1847) (Anomura: Galatheidae), reared in the laboratory

“…The additional zoeal stage found in this study can also be attributed to the fact that larval developments of decapod crustaceans can be highly variable in the number of larval stages and developmental pathways; a pattern that was however mainly attributed to caridean shrimps (Christiansen and Anger, 1990;Wehrtmann and Albornoz, 2003;Anger, 2006). Unfavourable environmental conditions such as low food availability, or unsuitable temperature and salinity, either in nature or in the laboratory, can modify the developmental sequence of decapod larvae (Thatje and Bacardit, 2000;Wehrtmann and Albornoz, 2003;and references therein).…”

Brachyuran and anomuran crabs associated with Schizoporella unicornis (Ectoprocta, Cheilostomata) from southeastern Brazil

“…ground for several of the species recorded in this study, as it provides the largest number of refuges for crabs ranging from 2.7 to 5.1 mm CW. The identification of substrate features such as texture can be a determining factor for decapod crustacean larval establishment and the stimuli for metamorphoses that take the individuals to the juvenile life stage (Anger 2006). The large number of individuals that could not be identified to species level because of their small sizes suggests the importance of these bryozoan colonies for the establishment and juvenile development of at least some species.…”