Papers by Victor Benno Meyer-Rochow
Experimental Biology, 1990
The electroretinogram (ERG) waveform of Petrolisthes elongatus is biphasic and transient and does... more The electroretinogram (ERG) waveform of Petrolisthes elongatus is biphasic and transient and does not change with age (monitored as carapace length and weight of the individual). Though there was a very slight decrease in sensitivity with age (R2 = 0.008), spectral peaks and curves remained virtually unchanged. A shift of 2.2 log units in threshold sensitivity, however, was observed in relation to the different adaptational states. The greatest difference, not unexpectedly, occurred between dark-adapted eyes, tested at night, and light-adapted eyes tested during the day at a background illumination of 250 1x. The gradient of the V/LogI curve (n) in light-adapted animals increased, which means a smaller increase in intensity is required to produce an increase in response compared to a dark-adapted animal, but there was no difference in n with regard to the different age-groups. Also, no significant difference was noticed between dark-adapted eyes tested during day and night. It is concluded that the intensity range over which vision in P. elongatus is maximally sensitive to contrast (the dynamic range) is 2.5-3.0 log units. Since there is apparently little or no alteration in the photic environment and the behaviour of P. elongatus as it ages, there is no advantage in fundamentally altering the parameters of the absolute and spectral sensitivity function with age. Our observations suggest that the eyes are able to adjust within 30 min to changing ambient light levels irrespective of whether or not a circadian activity rhythm operates.
Journal of Ethnobiology and Ethnomedicine, Dec 1, 2013
Journal of Ethnobiology and Ethnomedicine, Jan 16, 2013
The Journal of Allergy and Clinical Immunology, Jun 1, 2003
Zenodo (CERN European Organization for Nuclear Research), Aug 31, 2003
EMBO Reports, Oct 1, 2011
Journal of Cancer Education, Sep 1, 2012
Evolutionary principles suggested by Darwin and Wallace some 150 years ago can provide insights i... more Evolutionary principles suggested by Darwin and Wallace some 150 years ago can provide insights into the origins of cancer. Moreover, they can form a basis for answering the question implicitly posed when Nixon declared the war on cancer in 1971: Can we actually 'cure' cancer? As explained lucidly by Greaves in 2001, necessary keys to evolution and thus for the origin of species, including ours, are changes of genes or mutations; but changes of genes are also necessary links in the causal chains which lead to cancer. In effect, cancer is therefore, according to Greaves, an 'evolutionary legacy'. Intriguingly, the realization that cancer is a consequence of changes in genes which are conditiones sine qua non for evolution suggests a mutation paradox on an evolutionary scale: in individuals, mutations may have devastating adverse health effects, including cancer. Populations, however, as a whole can be expected to benefit ultimately from changes of genes to better adapt to environmental challenges. On the basis of premises from evolution theory, it remains for us to interweave growing insights into evolutionary principles with realistic objectives for the primary prevention of and, where the latter fails, coexistence with cancer so that what we do for patients can become more of an art rather than a war.
Journal of The Royal Society of New Zealand, Dec 1, 1994
... Journal of experimental Biology 119: 115-131. Hariyama, T.; Meyer-Rochow, VB; Eguchi, E. 1986... more ... Journal of experimental Biology 119: 115-131. Hariyama, T.; Meyer-Rochow, VB; Eguchi, E. 1986: Diurnal changes in structure and function of the compound eye of Ligia exotica (Crustacea, Isopoda). Journal of experimental Biology 123: 1-26. ...
New Zealand Entomologist, 1984
Ecological Entomology, Dec 9, 2017
Copeia, Aug 25, 1977
... In the holotype the labial bones are clearly visible and are essentially as illu-strated for ... more ... In the holotype the labial bones are clearly visible and are essentially as illu-strated for Gnathophis habenatus (Richardson) and G. incognitus ... was carried out during the 1975 'Alpha Helix' South East Asia Bioluminescence Expedition, and supported by a Queen Eliza-beth II ...
Proceedings of the Royal Society of London, Apr 22, 1988
The troglobitic harvestmenMegalopsalis tumidaandHendea myersi cavernicolainhabit the Waitomo Cave... more The troglobitic harvestmenMegalopsalis tumidaandHendea myersi cavernicolainhabit the Waitomo Caves in New Zealand with their luminescent prey, the glow-wormArachnocampa luminosa. A distribution map of the harvestmen in the caves is presented. Both species of harvestman possess two prominent eyes on the cephalothorax, with lens diameters ofca. 500 μm and 250 μm forMegalopsalisandHendea, respectively. The eyes are of the everted (direct) type, with axons leaving the retina peripherally in a single optic nerve. Retinal organization is typical for harvestmen: rhabdomal groups are made up of three or four photoreceptive cells. Rhabdoms inMegalopsalisareca. 250 μm long and possess diameters of up to 20 μm, whereas the corresponding figures forHendeaare 150 μm and 26 μm. Movement of screening pigment granules into dark or light-adapted positions could be induced at any time of day.f-Numbers of 1.06 forMegalopsalisand 0.97 forHendealenses indicate considerable light-gathering power of the dioptric system, which does not appear to be wasted because of the massively developed, voluminous rhabdoms in the retina of both species. Electrophysiological recordings showed that both species are sensitive to a range of light intensities covering at least 5 log units of magnitude. In terms of electroretinogram (ERG)-determined spectral sensitivityMegalopsalisdisplayed high ultraviolet sensitivity and a secondary broad peak ranging from blue to green light, whereasHendeapossessed a clear green peak and secondary sensitivity to blue and ultraviolet radiation. Both species demonstrated an overall negatively phototactic response to a bright ultraviolet light source and a positively phototactic response to a dim, artificial ‘glow-worm’ light. Only three individuals ofMegalopsalisand noHendeawere caught in six automatic traps a few metres outside the cave entrance over a period of five months, but within the cave 92Megalopsalisand 174Hendeawere sampled in 12 collecting trips ofca. 4 h each, spread over one year. The relative lack of photoreceptor regression, despite the cave existence of the two species and their inability to produce light, is interpreted as a consequence of the light produced by the cave populations of glowworms.
Natura Croatica : Periodicum Musei Historiae Naturalis Croatici, Sep 30, 2001
International Review of Social Research, Jun 1, 2018
Acta Parasitologica, 2001
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Papers by Victor Benno Meyer-Rochow