Berger, I. & G. Maier. (2001). The mating and reproductive biology of the freshwater planktonic calanoid copepod Eudiaptomus gracilis. Freshwater Biology 46(6):787-794.
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Berger, I. & G. Maier
2001
The mating and reproductive biology of the freshwater planktonic calanoid copepod Eudiaptomus gracilis.
Freshwater Biology
46(6):787-794.
Publication
Available in Wilson Copepod Library (non-digital)
Available for editors
Quantitative aspects of the mating and reproductive biology of the freshwaterplanktonic calanoid copepodEudiaptomus gracilis, including duration and frequency ofmating, duration of various phases of the oviducal cycle, egg production rate and adultlongevity were studied under laboratory conditions. One set of copepods was fed the algaChlamydomonas reinhardtiiwhose density was adjusted to 2¥105cells mL)1(about10 mg C L)1), another set was fed a mixed diet consisting of natural plankton (copepodnauplii, small rotifers and large algae) in the size range of 50±150lm (dry massapproximately 90 mg L)1).2. The entire mating process, from the grasping of the female by the male's rightgeniculate antennule to the separation of the pair, lasted about 2 min. Spermatophoreplacement started at about 30 s to 1 min after mating began and took approximately 1 min.Immediately after the spermatophore had been Æxed in the female's genital segment, thepair separated.3. The total oviducal cycle, including the gravid phase where the female carried ripeoocytes and the non-gravid phase where the female did not carry ripe oocytes, lasted about5±6 days. The non-gravid phase was particularly long; it was longer than the gravid phaseand constituted 62±72%of the total cycle.4. Mating and spermatophore placement usually occurred with gravid females althoughoccasionally (in 30 of 200 observations) spermatophores were attached in the genitalsegment of non-gravid females. Generally two to four, but up to seven, spermatophoreswere observed at a female's genital segment at the same time.5. Clutch size, rate of egg production and adult longevity depended on food. When fed onC. reinhardtii, females carried 7±8 eggs clutch)1, produced a mean of 1.3 clutches and lived14 days on average. When fed natural mixed food, females carried 10 eggs clutch)1,produced 5.6 clutches and lived 37 days on average.6. Removal of males after the Ærst clutch resulted in no further egg production. Re-matingis necessary inE. gracilisfor continuous clutch production and the production of fertileeggs.7. Mating duration is comparatively short and the non-gravid phase comparatively long inE. gracilis. This could be an adaption to the life in the pelagic zone of the lake, where Æshpredators are present. Fish select ovigerous females, pairsin copulaand, probably, femaleswith ripe oocytes which make them conspicuous. Thus, a short mating duration and aprolonged period without conspicuous oocytes, can be advantageous
