On the biology of <i>Calanus finmarchicus</i>. VII. Factors affecting egg production

Marshall, S. M.; Orr, A. P.

doi:10.1017/s0025315400012959

Cited by 145 publications

(74 citation statements)

References 6 publications

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“…Since Marshall & Orr (1952) found that the minimum period from feeding of radioactive food to production of radioactive eggs was ca 6 to 8 h for Calanus finmarchicus, the egg production rate recorded on Day 1 might represent in situ egg production rate. The mean egg production rate on Day 1 was 53.6 eggs female' d-'.…”

Section: Egg Production Ratementioning

confidence: 99%

Induction of reproductive failure in the planktonic copepod Calanus pacificus by diatoms

Uye¹

1996

Mar. Ecol. Prog. Ser.

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The inhibitory effect of diatoms upon egg viability was investigated by feeding the planktonic copepod Calanus pacificus (collected in coastal waters off Oregon. USA) 3 diatom species (Chaetoceros difficilis, Ditylurn brightweh, isolated from Oregon coastal waters, and Thalassiosira weissflogii, from culture collections at Oregon State University) ad libitum (2.6 to 3.9 mg C I-'). These diatoms induced the production of abnormal eggs which failed to hatch or hatched into deformed nauplii. In contrast, a dinoflagellate diet (Prorocentrum mlnirnurn, from the culture collections) resulted in the production of normal eggs, 96 6 , of which hatched into healthy nauplii. D~atom inhibitory effect disappeared quickly ( c 2 to 3 d ) when females were transferred from diatom suspensions to dinoflagellate suspension. The inhibitory effect was also apparent when newly spawned eggs were exposed to dense diatom cell extracts, indicating that blocking of the embryonic development is chemically mediated. The production of unidentified anti-mitotic chemical compounds by diatoms may be ubiquitous.

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Section: Egg Production Ratementioning

confidence: 99%

Induction of reproductive failure in the planktonic copepod Calanus pacificus by diatoms

Uye¹

1996

Mar. Ecol. Prog. Ser.

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“…Some copepod families (within the Diaptomoidea) require repeat mating because they are unable to store sperm and often have near equitable sex ratios [17,18]. Others (many non-Diaptomoidea families) are able to store sperm [19] and can produce multiple batches of eggs from a single copulation event [14,20]. Higher rewards from single mating events may lead males to high mortality risk when mate searching.…”

Section: Introductionmentioning

confidence: 99%

Macroevolutionary patterns of sexual size dimorphism in copepods

Hirst

Kiørboe

2014

Proc. R. Soc. B.

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Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their femalebiased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes.

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“…reviews by Cushing 1951 andBainbridge 1961) and daily feeding (Stearns 1986 and references therein), diel egg laying by copepod zooplankters is a shortinterval, cyclic behavior that is sparsely documented. Although few copepod species have been tested specifically for such behavior, it is becoming clear that dramatic changes in egg production can occur on a time scale of hours (Harding et al 1951, Marshall & Orr 1952, Mullin 1968, Spindler 1971, Valentin 1972, Gophen 1978, Saint-Jean & Pagano 1983, Marcus 1985, Runge 1985. If diel egg laying behavior is common, it would have important consequences for ecological theory dealing with secondary production in aquatic systems, because present production coefficients of models do not reflect short-term changes in egg production rate.…”

Section: Introductionmentioning

confidence: 99%