scholarly journals Visual Signalling in Plant-Animal Interactions

2021 ◽  
Author(s):  
◽  
Nik Fadzly N Rosely
Keyword(s):  
New Zealand ◽  
Geographical Location ◽  
Human Perception ◽  
Basic Research ◽  
Species Interaction ◽  
Visual Signals ◽  
Fruit Colour ◽  
Colour Perception ◽  
Visual Signalling ◽  
Colour Signals

<p>The process of visual signalling between plant and animals is often a combination of exciting discoveries and more often than not; highly controversial hypotheses. Plants and animals interact mutualistically and antagonistically creating a complex network of species relations to some extent suggesting a co evolutionary network. In this study, I investigate two basic research questions: the first is how plants utilize aposematic and cryptic colours? The second is how animals are affected by the colour signals broadcasted by plants? By using the avian eye model, I discover how visual signals/colours from plants are actually perceived, and the effects of these signals on birds (not human) perception. Aposematism and crypsis are common strategies utilized by animals, yet little evidence is known of such occurrences in plants. Aposematic and cryptic colours were evaluated by studying different colouration strategy through the ontogeny of two native heteroblastic New Zealand plants: Pseudopanax crassifolius and Elaeocarpus hookerianus. To determine the potential effect of colour signals on animals, I investigated an evolutionary theory of leaf colours constraining the conspicuousness of their fruit colour counterparts. Based on the available data, I also conducted a community level analysis about the effects of fruit colours and specific avian frugivores that might be attracted to them. Finally, I examined the fruit colour selection by a frugivorous seed dispersing insect; the Wellington Tree Weta (Hemideina crassidens). My result shows that aposematic and cryptic colours are successfully applied by plants to either warn or remain inconspicuous from browsing herbivores. The evidence I presented lends support to the Moa browsing hypothesis in relation to constraining the conspicuousness of their fruit colour counterparts. Based on the cryptic plant colourations. However, the same level of selective interaction could not be inferred for frugivore fruit colour selection based on avian vision. I demonstrated that leaf reflectance does not constrain/influence the conspicuousness of fruit colours. There was also no fruit colour diversity based on geographical location. Fruit colour alone is not sufficient to influence a specific frugivore assemblage. Other environmental factors and species interaction must be taken into account. Weta proved to possess colour vision capable of colour perception even in low light conditions. Weta also consistently selected naturally blue streaked and manipulated blue coloured fruits of Coprosma acerosa in a binary test. This supports the idea of weta co- evolving with fruit colours of certain divaricating plants in New Zealand. I suggest that the fruit colours of New Zealand are shaped by the combined selection pressure from birds, lizards/geckos and weta.</p>

scholarly journals Visual Signalling in Plant-Animal Interactions

2021 ◽  
Author(s):  
◽  
Nik Fadzly N Rosely
Keyword(s):  
New Zealand ◽  
Geographical Location ◽  
Human Perception ◽  
Basic Research ◽  
Species Interaction ◽  
Visual Signals ◽  
Fruit Colour ◽  
Colour Perception ◽  
Visual Signalling ◽  
Colour Signals

<p>The process of visual signalling between plant and animals is often a combination of exciting discoveries and more often than not; highly controversial hypotheses. Plants and animals interact mutualistically and antagonistically creating a complex network of species relations to some extent suggesting a co evolutionary network. In this study, I investigate two basic research questions: the first is how plants utilize aposematic and cryptic colours? The second is how animals are affected by the colour signals broadcasted by plants? By using the avian eye model, I discover how visual signals/colours from plants are actually perceived, and the effects of these signals on birds (not human) perception. Aposematism and crypsis are common strategies utilized by animals, yet little evidence is known of such occurrences in plants. Aposematic and cryptic colours were evaluated by studying different colouration strategy through the ontogeny of two native heteroblastic New Zealand plants: Pseudopanax crassifolius and Elaeocarpus hookerianus. To determine the potential effect of colour signals on animals, I investigated an evolutionary theory of leaf colours constraining the conspicuousness of their fruit colour counterparts. Based on the available data, I also conducted a community level analysis about the effects of fruit colours and specific avian frugivores that might be attracted to them. Finally, I examined the fruit colour selection by a frugivorous seed dispersing insect; the Wellington Tree Weta (Hemideina crassidens). My result shows that aposematic and cryptic colours are successfully applied by plants to either warn or remain inconspicuous from browsing herbivores. The evidence I presented lends support to the Moa browsing hypothesis in relation to constraining the conspicuousness of their fruit colour counterparts. Based on the cryptic plant colourations. However, the same level of selective interaction could not be inferred for frugivore fruit colour selection based on avian vision. I demonstrated that leaf reflectance does not constrain/influence the conspicuousness of fruit colours. There was also no fruit colour diversity based on geographical location. Fruit colour alone is not sufficient to influence a specific frugivore assemblage. Other environmental factors and species interaction must be taken into account. Weta proved to possess colour vision capable of colour perception even in low light conditions. Weta also consistently selected naturally blue streaked and manipulated blue coloured fruits of Coprosma acerosa in a binary test. This supports the idea of weta co- evolving with fruit colours of certain divaricating plants in New Zealand. I suggest that the fruit colours of New Zealand are shaped by the combined selection pressure from birds, lizards/geckos and weta.</p>

scholarly journals Influence of packing method on colour perception improving the appearance of fruits and vegetables

2008 ◽  
Vol 54 (No. 2) ◽  
pp. 97-103 ◽  
Author(s):  
B. Dobrzański ◽  
R. Rybczyński
Keyword(s):  
Fruits And Vegetables ◽  
Human Perception ◽  
Quality Parameters ◽  
Influential Factor ◽  
Major Influence ◽  
Fruit Colour ◽  
Quality Estimation ◽  
Colour Perception ◽  
Important Quality ◽  
Packing Method

The appearance of fruits and vegetables has a major influence on the perceived quality. Therefore, colour is one of the most important quality parameters in consumers’ preferences. Fruits differently exposed to the sun differ in colour, frequently looking unripe and reach full maturity just on handling or transport, some still green and appearing unripe. Oranges, carrot, red beet, and parsley were used for the study of the quality estimation. Different nets used for the packing of fruits were tested. The measurements of lightness and chromaticity parameters were performed according to L*a*b* system. The red net used for the packing of oranges caused a decrease of the lightness parameter L* for all stages of fruits maturity. However, some unripe and bright oranges, through the use of a red net, looked more mature. The chromaticity parameter a* is the most influential factor affecting the human perception of the fruit colour. The red net improves this parameter significantly, thus unripe yellow oranges become more saturated, changing the perception of colour to the predicted range. The colour is insignificant for the net, however, it is important for the classification and quality assessment by humans.

scholarly journals Role of accelerators in innovation ecosystems: The case of New Zealand

2020 ◽  
Vol 46 (1) ◽  
pp. 47-59
Author(s):  
Bryce Blair ◽  
Mohammad Saud Khan ◽  
Rehan Iftikhar
Keyword(s):  
New Zealand ◽  
Geographical Location ◽  
Secondary Data ◽  
Business Environment ◽  
Senior Executives ◽  
Structured Interviews ◽  
Innovation Ecosystem ◽  
Term Outcome ◽  
Long Term Outcome

This article aims to examine the evolution of the business accelerators and their impact in New Zealand over the course of last decade to develop a better understanding of the role accelerators have played within the New Zealand innovation ecosystem, their influence on the innovation community and how accelerators measure their success. An exploratory qualitative study was undertaken which mainly draws from semi-structured interviews with mentors, participants and senior executives of accelerator programs. Secondary data were collected from presentations on YouTube, consultancy reports and internal reporting to provide context for the interviewee’s perspective. New Zealand with its remote geographical location, distinct company environment and its uniqueness within the wider business environment and institutional configuration provides a novel context to this study. The findings indicate that after more than a decade of operations, long-term outcome and benefits of accelerators to New Zealand innovation ecosystem are still unclear.

scholarly journals Visual Warning Signals Optimized for Human Perception: What the Eye Sees Fastest

2005 ◽  
Vol 2 (1) ◽  
pp. 45-52 ◽  
Author(s):  
B. L. Gros ◽  
D. S. Greenhouse ◽  
T. E. Cohn
Keyword(s):  
Human Perception ◽  
Warning Signal ◽  
Sensitivity Function ◽  
Visual Signals ◽  
Temporal Contrast ◽  
Warning Signals ◽  
Moving Stimuli ◽  
Classic Problem ◽  
Speed Advantage ◽  
Spatio Temporal

This study aimed to answer the question of how to design a visual warning signal that is most easily seen and produces the quickest reaction time. This is a classic problem of bionic optimization—if one knows the properties of the receiver one can most easily find a suitable solution. Because the peak of the spatio-temporal contrast sensitivity function of the human visual system occurs at non-zero spatial and temporal frequencies, it is likely that movement enhances the detectability of threshold visual signals. Earlier studies employing extended drifting sinewave gratings bear out this prediction. We have studied the ability of human observers to detect threshold visual signals for both moving and stationary stimuli. We used discrete, localized signals such as might be employed in aerospace or automotive warning signal displays. Moving stimuli show a superior detectability to non-moving stimuli of the same integrated energy. Moving stimuli at threshold detectability are seen faster than non-moving threshold stimuli. Under some conditions the speed advantage is over 0.25 seconds. Similar advantages have also been shown to occur for suprathreshold signals.

scholarly journals Acquisition of a conditioned reflex in New Zealand White rabbits from three sources

1995 ◽  
Vol 29 (4) ◽  
pp. 394-399 ◽  
Author(s):  
E. James Kehoe ◽  
Amanda J. Horne ◽  
Jennifer Kingham ◽  
Thomas Martin ◽  
Wayne Roach
Keyword(s):  
New Zealand ◽  
Conditioned Reflex ◽  
Present Experiment ◽  
Conditioned Response ◽  
Tactile Stimulus ◽  
Visual Signals ◽  
The Third ◽  
New Zealand White Rabbits ◽  
Rearing Conditions ◽  
Stimulation Of

In studies of learning using rabbits, there has been standardization of behavioural procedures across laboratories. Less attention has been paid to variation that may arise from genetic differences and/or differences in rearing conditions. The present experiment revealed that acquisition of a conditioned reflex can be affected dramatically by such differences. Specifically, the acquisition of a conditioned reflex in New Zealand White (NZW) rabbits from 3 different suppliers was compared. All rabbits received behavioural training in which a tone or a light signalled an electrotactile stimulation of the trigeminal nerve near the rabbits' right eye. This tactile stimulus reliably elicited an eyeblink. Repeated presentations of the auditory and visual signals followed by the tactile stimulus yielded the acquisition of a conditioned response (CR), namely closure of the eyelids during the warning period provided by the signal stimuli. Two of the groups showed steady CR acquisition at a rate that matched previous results in other laboratories as well as in the senior author's laboratory. However, the third group of rabbits showed very slow acquisition, and some rabbits failed to show any CR acquisition.

scholarly journals Visual signalling by asymmetry: a review of perceptual processes

1999 ◽  
Vol 354 (1388) ◽  
pp. 1383-1393 ◽  
Author(s):  
John P. Swaddle
Keyword(s):  
Fluctuating Asymmetry ◽  
Visual Signals ◽  
Focus Attention ◽  
Fitness Parameters ◽  
In The Wild ◽  
Perfect Symmetry ◽  
Experimental Protocols ◽  
Axis Of Symmetry ◽  
Visual Signalling ◽  
Signalling Systems

Individual levels of asymmetry in traits that display fluctuating asymmetry could be used as visual signals of phenotypic (and perhaps genotypic) quality, as asymmetry can often be negatively related to fitness parameters. There are some data to support this hypothesis but the experimental protocols employed have commonly resulted in asymmetries far larger than those observed in nature. To date, there has been little consideration of the ability of animals to accurately discriminate small asymmetries (of the magnitude observed in the wild) from perfect symmetry. This is key to assessing the plausibility of the asymmetry-signalling hypothesis. Here, I review the perceptual processes that may lead to the discrimination of asymmetry and discuss a number of ecologically elevant factors that may influence asymmetry signalling. These include: signal orientation, distance of trait elements from the axis of symmetry, trait complexity, trait contrast and colour, and the behaviour of both signaller and receiver. I also discuss the evolution of symmetry preferences and make suggestions as to where researchers should focus attention to examine the generality of asymmetry-signalling theory. In highly developmentally stable signalling systems the magnitude of asymmetry may be too small to be detected accurately and reliably, hence asymmetry signalling is unlikely to have evolved in these situations.

Factors affecting the concentration of vitamins in milk: I. Effect of breed, season and geographical location on fat-soluble vitamins

1964 ◽  
Vol 31 (1) ◽  
pp. 1-25 ◽  
Author(s):  
S. Y. Thompson ◽  
Kathleen M. Henry ◽  
S. K. Kon
Keyword(s):  
Vitamin D ◽  
New Zealand ◽  
Vitamin A ◽  
Milk Fat ◽  
Geographical Location ◽  
Mean Value ◽  
Carotene Content ◽  
Mean Values ◽  
Seasonal Trends ◽  
The North

SummaryTwo surveys were done, one in 1943–44 and one in 1958–60, of the seasonal variation in the concentration of vitamin A and carotene in milk fat from 13 different areas in Great Britain. In the 1958–60 survey α-tocopherol and vitamin D were also measured. The main purpose of the second survey was to find out if the marked swing from Shorthorns to Friesians, and the trend towards greater use of carotene-rich foods in winter feeds that occurred in the intervening 15 years, had affected the pattern of vitamin A activity. In addition, monthly samples of butter were obtained in 1958–59 from a single factory in New Zealand during a complete butter-making season (9 months) and were assayed for vitamin A, carotene, α-tocopherol and vitamin D. Three experiments were done to study the effect of breed on the vitamin A and carotene content of milk fat, and in one of them α-tocopherol and vitamin D were also determined.The seasonal trends for vitamin A and carotene were essentially the same in both surveys. A peak occurred in May after the spring flush of grass and was followed by a decline with a second peak in the autumn, except in 1959 when both the summer and autumn were very dry. Potencies were higher in the south than in the north, where the differences between summer and winter were more marked. In winter, mean vitamin A potencies of 5·8 and 7·7 μg/g fat were found for northern and southern areas, respectively; the corresponding values for β-carotene were 2·0 and 4·5 μg/g fat. Mean summer values were 8·8 and 9·7 μg/g fat for vitamin A and 5·1 and 6·5 μg/g fat for carotene, equivalent to increases of about 52 and 26% and about 155 and 44%, respectively, over winter values. Differences in mean potency between areas are explained by length of grazing season and type of winter feed.The concentration of vitamin A in the fat was essentially the same for Ayrshires, Friesians, Jerseys and Shorthorns but somewhat lower for Guernseys; that of carotene was higher for the Channel Island breeds, particularly Guernseys, than for the other breeds studied.Compared with this country, concentrations of carotene were higher and of vitamin A lower in milk fat from New Zealand, probably because of the predominance of Jersey cows in New Zealand herds. The seasonal trends for these vitamins were similar in both countries, but the spring peaks were earlier, the autumn peaks later and the summer declines more pronounced in New Zealand than in this country.Concentrations of α-tocopherol in British milk fat showed a trend similar to that found for both vitamin A and carotene and were again influenced by feeding practices. Mean values of 23 and 29 μg α-tocopherol/g fat were found in the summer for northern and southern areas, respectively; the corresponding winter values were 15 and 23 μg/g fat. Mean values of about 30 μg/g fat were found, over a 28-month period, for the milk fat of each of the 3 breeds, Ayrshire, Friesian and Jersey. No seasonal trend was observed in the New Zealand samples; the mean value for the 9 months was 32 μg/g fat (range 24–39 μg).Vitamin D potencies were higher in summer, when there is more sunshine, than in winter. The higher summer values in the northern than in the southern part of the country may have been related to a higher intake of vitamin D in the former from hay and pasture. Summer potencies of 0·44, 0·53 and 0·62 i.u. vitamin D/g fat, respectively, were found for Friesian, Jersey and Ayrshire milk; corresponding winter values were 0·06, 0·08 and 0·9 i.u./g fat. For the New Zealand butters, summerues values were higher than in this country, about 0·7 compared with about 0·4 i.u./g fat; winter values were similar in both countries.

scholarly journals Temporal variation in acoustic and visual signalling as a function of stream background noise in the Bornean foot-flagging frog, Staurois parvus

2017 ◽  
Vol 1 (1) ◽  
pp. 1-1 ◽  
Author(s):  
T. Ulmar Grafe ◽  
Joremy A. Tony
Keyword(s):  
Background Noise ◽  
Temporal Dynamics ◽  
Multimodal Communication ◽  
Visual Signals ◽  
High Background ◽  
Dynamic Selection ◽  
Multimodal Signals ◽  
High Background Noise ◽  
Noisy Conditions ◽  
Visual Signalling

High background noise can interfere with signal detection and perception. Bornean foot-flagging frogs,Staurois parvus, live along noisy streams and use both acoustic and visual signals to communicate. It remains unclear why acoustic signalling is retained given that visual signalling appears to have clear advantages under these noisy conditions. We hypothesized that temporal dynamics in stream noise have shaped the multimodal communication system inS. parvuswith acoustic signalling at an advantage under more quiet conditions, whereas visual signals will prevail when the noise of rushing water is high after rains. We found that as predicted, maleS. parvusincreased foot flagging and decreased advertisement calling when presented with playbacks of stream noise compared to less noisy pre-playback conditions. Such context-dependent dynamic-selection regimes are recently gaining wider attention and enhance our understanding of the flexibility seen in the use of multimodal signals inS. parvus.

Marine conservation in New Zealand

1995 ◽  
Vol 2 (1) ◽  
pp. 55 ◽  
Author(s):  
Robert G. Creese ◽  
Russell G. Cole
Keyword(s):  
New Zealand ◽  
Habitat Restoration ◽  
Marine Reserves ◽  
Basic Research ◽  
Marine Conservation ◽  
Marine Biota ◽  
Research Needs ◽  
Large Fish ◽  
The Past ◽  
Set Up

Marine conservation in New Zealand lags behind the achievements on land. This is largely because conservation issues in the sea have not been as readily apparent until more recent times. Although the marine environment has not suffered from the same scale of degradation as the terrestrial one, there are many present and potential threats that need to be addressed. Impacts from fishing, aquaculture, species introductions, coastal developments and pollution are briefly reviewed. With one notable exception, remedial measures for these impacts are not well developed. The exception is the establishment of marine reserves in which all marine biota is totally protected. Since the mid 1970s, New Zealand has set up 10 of these marine reserves, eight of them in the past five years. Preliminary research has demonstrated that dramatic changes in the densities, population size structures and behaviours of some large fish and invertebrates can occur, presumably as a result of this protection. This has prompted a realization that marine conservation measures are achievable and desirable. Further initiatives in marine reserves, and in other forms of conservation such as active habitat restoration and species enhancement, can be expected in the years ahead. More basic research needs to be done, however, with the fishing industry in particular devoting more money and effort to evaluating the environmental effects of its fishing activities.

scholarly journals Oxidative stress and condition-dependent sexual signals: more than just seeing red

2012 ◽  
Vol 279 (1741) ◽  
pp. 3121-3130 ◽  
Author(s):  
Michael Garratt ◽  
Robert C. Brooks
Keyword(s):  
Oxidative Stress ◽  
Mate Choice ◽  
Visual Signals ◽  
Ongoing Study ◽  
Sexual Signals ◽  
Visual Signalling ◽  
Signalling Systems

The links between fitness, health, sexual signals and mate choice are complex and subject to ongoing study. In 1999, von Schantz et al . made the valuable suggestion that oxidative stress may be an important missing piece of this complex puzzle. Their suggestion has been enthusiastically tested, with over 300 studies citing their paper, but most effort has concerned carotenoid-based (and to a lesser extent melanin-based) visual signals, predominantly in birds and fishes. Today, we know a great deal more about oxidative stress and related physiology, in both a pathological and regulatory sense, than we did in 1999. We revisit von Schantz et al .'s predictions and, more importantly, highlight novel mechanisms that could link oxidative stress with a range of energetically demanding signals, greatly increasing the scope from visual signalling systems that are usually discussed and nearly always tested. In particular, we argue that differences between individuals in their ability to regulate physiology related to oxidative stress may be an important factor influencing the production of sexual signals and the costs that are incurred from investment.

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