First evidence of some dinoflagellates reducing male copepod fertilization capacity

Abstract

Evidence is presented that hatching failure in Temora stylifera eggs can depend on poor sperm quality. Three dinoflagellate diets, Prorocentrum micans, Gymnodinium sanguinium, and Gonyaulax polyedra, significantly modified spermatophore production and reduced the fertilization capacity of male sperm after 6-12 d of continuous feeding. Two other diets, the dinoflagellate P. minimum and the prymnesiophycean Isochrysis galbana, had no effect on hatching success, which remained high (Ͼ89%) and stable with time. A reduction in fertilization capacity was neither due to maternal effects nor to male age since hatching success returned to normal upon the introduction of freshly caught wild males or males conditioned with a good diet such as P. minimum for the same length of time as couples fed with the poor diets, P. micans, G. sanguinium, and G. polyedra. Confocal microscope images of unhatched eggs colored with a nucleus-specific fluorescent dye confirmed that these eggs had not been fertilized. Experiments with Calanus helgolandicus females, which did not require reinsemination and which were fed the same diets that induced hatching failure in T. stylifera, showed no change in hatching success with time.Copepod fecundity has been shown to be strongly related to food type, with some foods that are better than others for promoting higher egg production. High production has been reported with dinoflagellate and ciliate diets (Gill and Harris 1987;Kleppel et al. 1991) since these are estimated to provide more protein, carbohydrates, and lipids than diatoms of equivalent volume (Kleppel 1993). But some dinoflagellates (Huntley et al. 1986) and microzooplankton (Stoecker and Egloff 1987; Sanders and Wickham 1993) appear to be poor food items for copepod production.Much less is known about how diet affects egg viability. Recent studies have indicated that low hatching success may depend on a nutritionally inadequate diet. Guisande and Harris (1995) demonstrated that hatching success in C. helgolandicus increased as egg size and total organic content of the eggs increased. However, Jónasdóttir (1994), Pond et al. (1996) found no significant correlation between egg size and hatching success in Acartia tonsa and C. helgolandicus. Differences in egg viability were related to the concentration of specific polyunsaturated fatty acids in the diet, in particular to the content of 20 : 53 and 22 : 63 (Kleppel and Burkhart 1995; Jónasdóttir and Kiørboe 1996), and were negatively correlated with the carbon and nitrogen content of the eggs (Pond et al. 1996).It has been suggested that low hatching success is related to the presence of antimitotic compounds in diatoms blocking egg development (Poulet et al. 1994Ianora et al. 1995Ianora et al. , 1996Miralto et al. 1995;Uye 1996;Ban et al. 1997). These authors have demonstrated that diatom diets induced the production of abnormal eggs that either failed to develop to hatching or hatched into deformed nauplii. This effect was diatom density dependent (Chaudron et al. 1996) and was...

Influence of algal diet on growth and ingestion of Calanus helgolandicus nauplii

“…Food quality is another possible factor influencing the production rate of copepods, as reported by Klein Breteler et al (1990) in studies on copepodite development and by Støttrup & Jensen (1990), Jónasdóttir (1994 and Ianora et al (1999) in studies on egg or spermatophore production rate, considered to be equivalent to copepodite growth rate for non-growing adults. In this paper, we found that those algae that produce the shortest duration of naupliar stages and those that produce the highest mean weight of Stages NV, NVI or CI (i.e.…”

Optimal mate choice patterns in pelagic copepods

“…While information about male mating rates are rare, the few which have been reported show that males are able to produce and deploy more than one spermatophore per day (Ceballos and Kiørboe 2011;Ceballos et al, unpublished data;Ianora et al 1999), whereas females do not need to be remated for several days or never during their lifetime (i.e., Ceballos and Kiørboe 2011;Hylstofte and Kiørboe 2011;Wilson and Parrish 1971). Therefore, especially at high population densities, females of all species are predicted to be choosy.…”

Zooplankton growth, diet and reproductive success compared in simultaneous diatom- and flagellate-microzooplankton-dominated plankton blooms

“…Differences in hatching success may not be related to food conditions at all, but e.g. gonadal development (Niehoff 1996), remating success (Parrish & Wilson 1978), sperm quality (Ianora et al 1999b), pollutants (Hook & Fisher 2001) and/or variable feeding history. Pellet production is a result of feeding activity within the last hour (e.g.…”