Two sibling species of Tisbe (Copepoda, Harpacticoida): Tisbe reluctans and T. persimilis n. sp. Research on their morphology and population dynamics

Volkmann-Rocco, B.; Fava, G.

doi:10.1007/bf00353436

Cited by 32 publications

(14 citation statements)

References 9 publications

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“…This is unfortunate because R, values would provide a way of comparing the rates of multiplication of copepods relative to their own generation time. R, values for two Tisbe species (semiplanktonic marine harpacticoids) are 58 and 32 individuals per female per generation (Volkman-Rocco and Fava 1969). These copepods had larger broods and a higher hatching success than B. zschokkei.…”

Section: Fecundity-because Interbrood Periodsmentioning

confidence: 99%

Stream‐dwelling copepods: Their life history and ecological significance1

O'Doherty

1985

Limnology & Oceanography

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The stream-dwelling harpacticoid copepod Bryocamptus zschokkei was reared in the laboratory at 3.5", lo", 15", 18", and 20°C with naturally conditioned leaf disks as a food source. Egg and naupliar development rates were fastest at 18°C.A complete life table experiment was conducted at 18°C. Females were longer-lived than other copepods and produced eggs continuously until death. The intrinsic rate of natural increase (r) and the net reproductive rate (R,) were found to be lower than those of most copepods. Reproduction is probably continuous throughout the year in the stream, since animals reproduced in the laboratory at the extreme temperatures experienced by the natural population. Since most copepods reproduce seasonally, the annual intrinsic rate of increase of B. zschokkei may be comparable to those of other copepods.

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Section: Fecundity-because Interbrood Periodsmentioning

confidence: 99%

Stream‐dwelling copepods: Their life history and ecological significance1

O'Doherty

1985

Limnology & Oceanography

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“…We find that the sex ratio fluctuates around 1 : 1 in harpacticoids and calanoids alike, which points to a common genetic mechanism of sex determination. A Battaglia (1957); Battaglia (1970); Parise and Lazzaretto (1966);Volkmann-Rocco and Fava (1969); Volkmann-Rocco and Battaglla (1972). deviation in favour of males a t high population densities, a s Heinle (1970) reports for Acartia tonsa, w a s never observed i n Amphiascoides s p .…”

Section: Pairing and Fertilitymentioning

confidence: 99%

Mechanisms of Density-Dependent Population Regulation in the Marine Copepod Amphiascoides sp. (Harpacticoida)

Walker¹

1979

Mar. Ecol. Prog. Ser.

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Amphiascoides sp. was cultured in the laboratory for the first time. Culture method and data on its life cycle are given. Reproductive potential and behaviour (pairing incidence) were studied in relation to population density (i.e. to medium conditioned by a previously dense population) and in relation to food supply. It was found that: (1) conditioned medium reduces the number of ovisacs per female by reducing its fertile period and by extending the interval between release of successive pairs of ovisacs, older females being more susceptible to this inhibition; (2) conditioned medium causes partial sterilization (nonfertilization?) of eggs; (3) these effects are partly, but not completely, reversible when females are returned to fresh medium (delayed, density-dependent effects); (4) crowding itself, but not medium conditioned by crowding, reduces the number of eggs per ovisac; (5) ovisacs are not released in absence of food, and food supply triggers the release of ovisacs; (6) mating incidence is a function of food supply; (7) mating incidence is higher in groups than in isolated pairs; (8) repeated mating is necessary for sustained fertility; (9) infertile periods in females as a result of deprivation of food or males may be compensated for by extension of the normal ( 5 0 4 0 d) fertile period to maximally 80-100 d; (10) the generation period (nauplius to fertile adult) increased by 40 '10 in the course of laboratory existence. These mechanisms of true population regulation via negative feedback are discussed in the light of the 'paradox of evolution under competition': resources are limited, yet, those genotypes that are getting more numerous than others (higher fitness) win the competition (= positive feedback).

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“…Some incipient crossing barrier may be developing between populations of wild oysters in Long Island Sound and in Maine (Longwell and Stiles, unpublished information). Natural populations, at least superficially undistinguishable morphologically but reproduc tively isolated, found in all groups of animals (Mayr 1942) are known to exist in the marine copepods, Tisbe (Volkmann-Rocco andFava 1969, Battaglia 1970), and in a number of genera of crustacea, including Artemia (Harding 1950, Staiger and Bocquet 1954, Halfer-Cervini et al 1968. Gamete incompatibility may play a role in some of these species.…”

Section: Discussionmentioning

confidence: 99%