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  • 1
    Electronic Resource
    Electronic Resource
    Mosquito Sugar Feeding and Reproductive Energetics (1995)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Entomology 40 (1995), S. 443-474 
    Details
    ISSN: 0066-4170
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.en.40.010195.002303
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  • 2
    Electronic Resource
    Electronic Resource
    Free-running activity rhythm in the natural environment (1977)
    [s.l.] : Nature Publishing Group
    Nature 269 (1977), S. 796-797 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The peaks of locomotory activity in the natural habitat did not exhibit constant relationships to the times of dawn and dusk. The interval between day peaks of activity during a sequence of non-covering tides was less than 24 h. The slope of the regression line for the first 6 d illustrated in Fig. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/269796a0
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  • 3
    Electronic Resource
    Electronic Resource
    Evidence for the dilution effect in the selfish herd from fish predation on a marine insect (1981)
    [s.l.] : Nature Publishing Group
    Nature 293 (1981), S. 466-467 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] There are two reasons why it has proved difficult to obtain reliable evidence that the grouping of prey animals reduces the risk of predation by a simple dilution effect. First, predation attempts, particularly on vertebrate prey, tend to be relatively rare and it is therefore difficult to quantify ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/293466a0
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Reproductive behaviour of the ocean skater Halobates robustus (Hemiptera: Gerridae) in the Galapagos Islands (1982)
    Springer
    Oecologia 55 (1982), S. 202-207 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field observations on the ocean skater, Halobates robustus Barber showed that the flotillas of adults, unlike those of juveniles, occurred very close to the shore at specific sites from which they were not easily dislodged. The adult flotillas consisted of small all-male groups or aggregations of males and copulating pairs. The proportion of free males in copulating flotillas decreased with increasing group size. There was no correlation between the sizes of the paired males and females. Single adult females, which were not observed in the copulating flotillas, were usually teneral with undeveloped eggs. In contrast, the copulating females contained numerous well-developed eggs. The pairs remained in prolonged genital contact. The behaviour of free males in copulating flotillas was characterized by frequent, non-random encounters with copulating pairs. Experiments with marked individuals established that male take-overs can occur within flotillas. It is concluded that the copulating flotillas are initiated by the males and not only provide protection from predators, as previously shown, but also act as arenas for mate finding and selection. It is presumed that prolonged copulation reduces sperm competition between contending males.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384488
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  • 5
    Electronic Resource
    Electronic Resource
    Activity rhythms and the tide in a saltmarsh beetle Dicheirotrichus gustavi (1983)
    Springer
    Oecologia 60 (1983), S. 111-113 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Field observations at Mersea Island, Essex confirm previous observations at Scolt Head Island, Norfolk that the intertidal beetle Dicheirotrichus gustavi Crotch (Coleoptera: Carabidae) has a rhythm of activity on the saltmarsh surface which is suppressed during periods of submerging tides. Although the timing of the tides at the two sites is 180° (6 h) out of phase, the timing of beetle activity at the two sites is the same, with a peak of activity shortly after dusk. Beetle activity therefore shows no special phase relationship with the “critical” tide — the first high tide that covers the beetle zone after a period of emergence. At Mersea, the peak of beetle activity coincides with the critical high tides, but the beetles were observed to escape from the seawater by scrambling up the mud and vegetation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379328
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  • 6
    Electronic Resource
    Electronic Resource
    Museum's plans beyond belief (1990)
    [s.l.] : Nature Publishing Group
    Nature 345 (1990), S. 568-568 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/345568b0
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  • 7
    Electronic Resource
    Electronic Resource
    Short-term changes in activity rhythms in an intertidal arthropod (Acarina: Bdella interrupta Evans) (1979)
    Springer
    Oecologia 38 (1979), S. 291-301 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary On a marine saltmarsh, the intertidal mite, Bdella interrupta Evans, is exposed to periods of regular tidal submergence which alternate with periods of tidal emergence. The mite shows well defined day and night peaks of locomotory activity on the soil surface. During periods of tidal submergence the activity peaks showed an apparent periodicity, of around 12.5 h, characteristic of a tidal rhythm. In the presence of non-submerging tides the periodicity of the activity peaks changed to around 11.5 h. It is suggested that this shorter periodicity results either from free-running of the circatidal clock in the absence of entraining tides or from a sequence of transients that are phaseshifting towards a stable relationship with a second zeitgeber. It is further suggested that the alternation between a ca. 12.5 h and a ca. 11.5 h rhythm ensures that an activity peak is maintained in daylight and, also, reduces the possibility of inundation during the first critical floodings during sequences of rising spring tides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345189
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  • 8
    Electronic Resource
    Electronic Resource
    Synchronization of activity rhythms with the tide in a saltmarsh collembolan Anurida maritima (1981)
    Springer
    Oecologia 50 (1981), S. 265-270 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary On a marine saltmarsh, the intertidal collembolan Anurida maritima (Guérin) has a well-defined tidal rhythm of activity on the mud surface between submerging tides: a large proportion of the individuals emerge from their underground refuges shortly after the retreat of the tide, forage there for a few hours, and retire underground at least 1 h before the return of the tide. This activity rhythm has a period of about 12.4 h and it persists in the field during sequences of non-submerging tides and in the laboratory away from the tides in constant light. In the field the level of activity is greatly reduced during the night. It is suggested that the function of this tidal rhythm is to enable individual Anurida to anticipate the return of the tide both during periods of regular, twice-daily tidal submergence and after a period of days when the habitat has not been covered by the tide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348049
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  • 9
    Electronic Resource
    Electronic Resource
    The distribution of an intertidal aphid, Pemphigus trehernei foster, on marine saltmarshes (1975)
    Springer
    Oecologia 21 (1975), S. 141-155 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The intertidal aphid, Pemphigus trehernei, is restricted to aster plants (Aster tripolium) growing near the edges of creeks and salt pans in low areas on tidal saltmarshes. Aphid populations in mid-marsh areas do not show an equivalent edge effect. In low-marshes the edge soil generally has more surface cracks and cavities which can accommodate aphids and a higher % air space than soil from regions away from edges. Adults and 1st instars can penetrate edge soil more readily than non-edge soil. Aphid abundance is positively correlated with % air space in low-marsh regions. Aphid populations established on potted asters were destroyed or reduced to very low levels when transferred to non-edge regions of low-marsh areas. It is suggested that aphid distribution is primarily limited by soil conditions, especially the extent of soil drainage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345557
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  • 10
    Electronic Resource
    Electronic Resource
    Sex ratio, local mate competition and mating behaviour in the aphid Pemphigus spyrothecae (1992)
    Springer
    Behavioral ecology and sociobiology 30 (1992), S. 297-307 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The primary sex ratio and the selective factors associated with it were investigated in the aphid Pemphigus spyrothecae. The sexuparae gave birth to an average of 1.99 ± 0.01 (1–2) males and 5.06 ± 0.09 (2–6) females [± SE (range), n = 147]. The average weight of individual males was 16.2±0.86 (13–18) μg (n = 5) and of females 40.7 ± 0.71 (38–46) μg (n = 15). The overall investment ratio by the mother sexuparae was therefore 1:6.4, equivalent to a proportionate investment in sons of 0.135 (interquartiel range: 0.117–0.165). There was a highly significant correlation between the size of the sexupara and the number of her daughters: the number of sons was independent of sexupara size. Field observations and laboratory experiments showed that the sexuparae aggregate on poplar bark before giving birth to the sexuals: they appear to behave in such a way that there is always at least one other sexupara in the crevice with them. The average number of sexuparae forming a “foundress” group, within which offspring could potentially mate with each other, was 2.48±0.19 (1–9) (n = 80). The life-time activity patterns of the sexuals (which moult four times but do not feed) was described. Both sexes are active shortly after birth; they are then immobile for a long period but become very active again after emerging as adults (after about 42 h in males, 51 h in females). Each male can mate with up to 14 females. The females are receptive to a second male for only a relatively short period (ca. 15–20 min) after their first mating. There is considerable competition between males during mating (just as intense between clonal sibs as non-sibs) and evidence for post-copulatory mate-guarding by the males. There is no evidence that females prefer to mate with non-sibs rather than sibs. The observed sex ratios and the mating behaviour of the aphids are discussed in relation to models of local mate competition assuming variable female fecundity, as developed by Frank (1987a, b) and Yamaguchi (1985) (the constant male hypothesis) and by Stubblefield and Seger (1990).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00170595
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