Sexual dimorphism in calanoid copepods: morphology and function

  title={Sexual dimorphism in calanoid copepods: morphology and function},
  author={Susumu Ohtsuka and Rony Huys},
Mate location and recognition are essentially asymmetrical processes in the reproductive biology of calanoid copepods with the active partner (the male) locating and catching the largely passive partner (the female). This behavioural asymmetry has led to the evolution of sexual dimorphism in copepods, playing many pivotal roles during the various successive phases of copulatory and post-copulatory behaviour. Sexually dimorphic appendages and structures are engaged in (1) mate recognition by the… 
Motility patterns and mate encounter rates in planktonic copepods
It is shown that pelagic copepods are capable of searching tens to thousands of liters of ambient water for mates daily, that search capacity increases approximately with the cube of copepod length for both chemical and hydrodynamic signalers, and that these impressive mate search volume rates are sufficient to sustain populations at typical adult densities.
Divergent mating system adaptations in microallopatric populations of Acanthodiaptomus denticornis (Copepoda, Calanoida)
It is suggested that planktivorous glassworm larvae, which inhabit only Lac de Montcineyre, impose selection on copulating pairs of copepods and may adaptively increase the ability of M males to fertilize eggs during short matings and indirectly decrease sensitivity of M females to male coercion.
Sexual size dimorphism in calanoid copepods (Centropagidae) from Patagonia (Argentina)
Interestingly, all species showed significant intraspecific stability in their sexual size dimorphism despite potential differences in their environments regarding predation pressure, environmental stability (permanent or temporary waters) and altitude distribution of populations.
Sex, sex-ratios, and the dynamics of pelagic copepod populations
Positive density dependent population growth during periods of low population density (‘Allee effect’) amplifies population density variation during winter into the subsequent summer, thus explaining why summer densities appear to depend more on winter densities than on current growth opportunities in pelagic copepods.
Heterospecific mating and partial prezygotic reproductive isolation in the planktonic marine copepods Centropages typicus and Centropages hamatus
Heterospecific mate encounter rates in the North Sea were maximal in late summer (August), up to~2,000 encounters m−3 d−1, and were comparable in magnitude to conspecific encounter rates during the same period, indicating that pheromone and hydromechanical precontact mating cues lack species specificity.
Mate finding, mating, and population dynamics in a planktonic copepod Oithona davisae: There are too few males
Three-dimensional video observations of free-swimming copepods revealed the mechanisms of mate finding in the cyclopoid copepod Oithona davisae, and suggests that population growth in this species is severely constrained by fertilization limitation.
Effects of Sex Change on Number of Olfactory Chemoreceptors in Lysmata Shrimp
The results show that the aesthetasc numbers of both male-phase and euhermaphrodite-phase shrimp are related in general to timing of sex change; in other words, those shrimp that change sex later have greater aesthetASC numbers than those that changesex earlier.
The contrariwise life of a parasitic, pedomorphic copepod with a non‐feeding adult: ontogenesis, ecology, and evolution
It appears that the life cycle of C. amphiodiae is pedomorphic, and probably evolved through a delay of metamorphosis regulated by developmental hormones, and the dominance of the larval phase to the greater potential for survival and growth of the enterozoic parasitic stages than of the free-living, post-metamorphic stages.
The relative importance of various mating criteria in copepods
It is found that copepods use several criteria when assessing mates and that these criteria are associated with different likelihood estimates, and the strongest likelihood of non-random mating whenCopepods assess the reproductive status of females or when copepod select between conspecific vs. heterospecific mates is reported.
What makes pelagic copepods so successful
Three features that are unique or almost unique to pelagic copepods among zoo-plankton may account for their numerical dominance in the pelagic realm of the oceans: (i) the torpedo-shaped body, the


Functional Significance of the Sexual Dimorphism in the Cephalic Appendages of Euchaeta Rimana Bradford
The parallel changes in the structure of the antennule as well as of the adjacent cephalic appendages suggest that a homeobox-like gene control system could be coordinating these morphological changes in Euchaeta rimana.
When in the presence of potential mates, males of the copepods Ezcrytemorn affinis, Eurytemora he&man& and Pseuclodiuptomus coronatus performed mate-seeking behavior which appeared to be oriented.
Dimorphism and possible sex change in copepods of the family Calanidae
The evolutionary and ecological significance of this presumptive hypothesis is that the larger-sized potential male reaching adulthood one or more weeks before maturation of genotypic females may increase its reproductive output by sex change in the course of the final molt to mature as a functional female.
Sexual communication in copepods and rotifers
The methods used by copepods and rotifers for mate seeking and recognition are compared, the behavioral evidence supporting the existence of chemical cues are described, and experiments describing the biochemical characteristics of the signal molecules are examined.
The ontogeny and phylogeny of copepod antennules
The ontogenetic analyses suggest that the timing of expression of intersegmental articulations during development may in future provide the most informative characters for phylogenetic study, rather than either segment numbers or the patterns of fused or undivided segments.
Female genital structures of Metridinidae (Copepoda: Calanoida)
The position and anatomy of these structures are compared to those of other families and genera, and a functional interpretation of their morphology is proposed.
Mating behavior of Labidocera aestiva (Copepoda: Calanoida)
It is hypothesized that the pit-pores secrete a substance which dissolves the cement binding the coupling device to the abdomen and aids the female to remove a discharged spermatophore from her urosome.
Directionality and Swimming Speeds in Predator-Prey and Male-Female Interactions of Euchaeta rimana, a Subtropical Marine Copepod
  • J. Yen
  • Environmental Science
  • 1988
This examination showed how the sexual dichotomy in morphology and feeding was reflected in the swimming behavior of Euchaeta rimana, and Directional swimming by the female predatory copepod supports the predictions of models in which encounter rate was maximized by swimming orthogonally to their mates and their prey.
Surface glycoproteins in copepods: potential signals for mate recognition
It is demonstrated that glycoproteins on the urosome of females from all six species are present at sites expected to be important in mate recognition, including at the caudal rami, gonopore, margin of the genital segment, and Urosome segment junctions.
Functional morphology and taxonomic relevance of the female genital structures in Acartiidae (Copepoda: Calanoida)
  • R. Barthélémy
  • Biology
    Journal of the Marine Biological Association of the United Kingdom
  • 1999
The present results do not justify the Steuer's subgenus division of the genus Acartia, the very predominant one of the family, and the functional morphology and taxonomic relevance of genital structures are discussed.