Reproductive periodicity of the sparid,Acanthopagrus pacificus,on a hierarchy of temporal scales

The reproductive periodicity of the sparid, Acanthopagrus pacificus, over four temporal scales is described. Acanthopagrus pacificus had a short spawning season between June and September, and within this, a peak reproductive period from July to early September. During the peak period there were several spawning peaks corresponding to a lunar periodicity, with intense reproductive activity on new and full moons that peaked during the period of the full moon when the tidal range was greatest. At the smallest temporal scale, spawning occurred at night on ebb tides. Because this study draws on data collected in 1991 and 1995, it provides a useful baseline against which to judge future changes in reproductive periodicity.     

Consequences of floral visits by ants and invasive honeybees to the hummingbird‐pollinated,Caribbean cactus Melocactus intortus

The pink, tubular, nectariferous flowers of Melocactus intortus (Cactaceae) in Puerto Rico are visited by native hummingbirds (Anthracothorax dominicus), but also by invasive honeybees (Apis mellifera) and ants (Solenopsis sp.). We sought to determine if the bees and ants significantly alter the pollination of M. intortus by measuring pollinator effectiveness. Using traditional estimates of effectiveness (visitation rate and seed set), our results show that hummingbirds were the most effective pollinators as expected. Bees and ants were less effective, and their contributions were one‐fourth to one‐tenth of that observed for hummingbirds. We then modified this measure of effectiveness by adding two components, fitness of progeny and temporal availability of visitors, both of which refine estimates of flower visitor effectiveness. With these new estimations, we found that the effectiveness values of all three animal visitors decreased; however, the role of hummingbirds as the principal pollinator was maintained, whereas the effectiveness values of bees and ants approached zero. By these new measures of overall pollinator effectiveness, the invasive honeybees and ants have little effect on the reproductive success of M. intortus.     

Domestication of the Emblematic White Cheese-Making Fungus Penicillium camemberti and Its Diversification into Two Varieties

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A comparison of life history traits of sexual and asexual strains of the parasitoid wasp,Lysiphlebus fabarum (Braconidae: Aphidiinae)

1. This study examined biological characteristics of sexual and asexual strains of the parasitoid wasp, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae). 2. Strains were reared in different instar hosts (the black bean aphid, Aphis fabae Scopoli) under identical environmental conditions (21 °C, 65–75% RH, and LD 16:8 h). 3. Results showed that the second instar of the aphid is the most suitable growth stage for both strains, as the wasps that emerged from the second instar hosts were larger, more fecund, and had larger egg size. Trade‐offs between the fitness components of the parasitoid were clearer when the parasitoids were reared in suboptimal instars. 4. According to the results, sexual females emerged around 1 day earlier and lived around 0.5 day less than asexual females. Also, sexual females emerged with a lower initial egg load, although these wasps tend to have larger eggs than asexual females. Asexual females may enjoy greater longevity and higher developmental plasticity which suggests a higher degree of synchronization with pest population dynamism. 5. The results suggest that sexual wasps, in contrast to asexual wasps, invest more in egg size than in egg load. This study suggests strain‐specific adaptations of L. fabarum to different instars of the black bean aphid by which the allocation of nutritional resources to various functions differs between strains. 6. Furthermore, differences in life history traits between strains can greatly influence the population dynamics of each strain, and hence their effectiveness in suppressing pest populations.     

Determination of adenosine triphosphate in human semen to estimate the fertilizing potential and to quantify sperm antibodies

The measurement of the ATP content of fresh semen is as accurate as the estimation of sperm motility by conventional methods in discriminating between semen of fertile versus subfertile men. The ATP content of frozen thawed donor semen is correlated with the probability of conception per cycle of insemination. Exact quantification of cytotoxic sperm antibodies in serum is possible with the adenosine-triphosphate-release-cytotoxicity test, since measurement is free of the bias of microscopic examination. The procedure has been simplified by testing only one serum dilution and calculating the ‘sperm toxicity index’.     

Certain observations on Scytonema stuposum (Kuetz.) Born. (Cyanophyta,Nostocales)

Some interesting cultural observations on Scytonema stuposum (Kuetz.) Born., were recorded. It was observed that frequently one or more terminal cells of a branch get cut off but they still remain attached over the sheath of the mother filament. Even in this condition such structures continue their growth and may become a multicellular body. Later, such a structure gets detached from the mother filament and serve as a hormogonium.     

Temporal patterns of breeding and recruitment in Nerophis lumbriciformis(Pisces; Syngnathidae) related to seawater temperatures

The breeding season of Nerophis lumbriciformis , a cold water pipefish, was positively correlated with seawater temperatures <15·5° C, whilst recruitment occurred at the end of the upwelling season, when seawater temperature attained its maximum values. The observed alterations in seawater temperatures, with steady year‐round increases, and the consequent alteration of the upwelling regime, may have dramatic consequences in the maintenance of N. lumbriciformis populations, by reducing the breeding period and simultaneously contributing to the transport of pelagic larvae northwards due to specific sea currents that occur outside the upwelling season.     

Preference and performance of the hyperparasitoid Syrphophagus aphidivorus (Hymenoptera: Encyrtidae): fitness consequences of selecting hosts in live aphids or aphid mummies

Abstract.  1. Theoretical models predict that ovipositional decisions of parasitoid females should lead to the selection of the most profitable host for parasitoid development. Most parasitoid species have evolved specific adaptations to exploit a single host stage. However, females of the aphid hyperparasitoid Syrphophagous aphidivorus (Mayr) (Hymenoptera: Encyrtidae) display a unique and atypical oviposition behaviour by attacking either primary parasitoid larvae in live aphids, or parasitoid pupae in dead, mummified aphids.
2. In the laboratory, the correlation between host suitability and host preference of S. aphidivorus on the host Aphidius nigripes Ashmead parasitising the aphid Macrosiphum euphorbiae (Thomas) was investigated.
3. The relative suitability of the two host stages was determined by measuring hyperparasitoid fitness parameters (survival, development time, fecundity, sex ratio, and adult size of progeny), and calculating the intrinsic rate of population increase ( r _m). Host preference by S. aphidivorus females and the influence of aphid defence behaviour on host selection was also examined.
4. Hyperparasitoid offspring performance was highest when developing from hosts in aphid mummies and females consistently preferred this host to hosts in parasitised aphids. Although aphid defensive behaviour may influence host selection, it was not a determining factor. Ecological and evolutionary processes that might have led to dual oviposition behaviour in S. aphidivorus are discussed.