4 research outputs found
Visual Signalling in Plant-Animal Interactions
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
Contribution of rice fields to bird diversity in Peninsular Malaysia
There is a lack of documentation on rice fields as an important habitat that harbour different bird diversity compared to natural habitats in Peninsular Malaysia. This study investigated the contribution of rice fields to bird diversity in Peninsular Malaysia. A total of 83 rice fields and 53 natural habitats throughout Peninsular Malaysia were included in this study. Birds were observed and counted using point-count and mist-netting methods. A total of 10,707 bird-sightings, with rice fields, recorded 129 species from 15 orders and 50 families from October 2013 to December 2014; whilst natural forests recorded a total of 438 species from 14 order and 59 families from February 1992 to January 2015. Diversity t-test showed a significant difference in the species richness between the two different habitats (t=11.009, p<0.05). The high values of Δ+and ʌ+ in many areas of rice fields were significantly influenced by the presence of waterbirds, albeit low species richness. This temporary wetland habitat harbours land birds and waterbirds in one place. The data presented here suggest that waterbirds and migratory birds in rice fields contribute significantly to the total bird species found in Peninsular Malaysia
Visual Signalling in Plant-Animal Interactions
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
Current observation on Aedes mosquitoes: A survey on implication of dengue infection, human lifestyle and preventive measure among Malaysia resident in urban and sub-urban areas
Objective: To evaluate the current knowledge level and information on Aedes mosquitoes and
dengue among Penang resident in urban (Sungai Dua) and sub- urban areas (Batu Maung).
Methods: The questionnaire comprises of twenty-three questions, surveyed on 202 respondents
regarding socio-demographic, the observation of general Aedes’ mosquito behaviour, dengue
infection threat, preventive measures against mosquitoes and lifestyle (on usage of artificial
light) in changing the behaviour of Aedes mosquitoes.
Results: The respondents in sub-urban Batu Maung showed less knowledge level regarding
Aedes mosquitoes as compared to respondents in urban Sungai Dua. There was a positive
association between biting frequency of mosquitoes with the lifestyle of respondents (in
relation to the light use), the use of personal protection and fogging operations conducted by
the Ministry of Health. There is a positive relationship between the knowledge of preferred
mosquitoes resting place and the respondent aged between 17 to 24 (78.2%) in sub-urban
Batu Maung. Urban Sungai Dua respondents showed a significant relation between the use of
lights and the resting places for Aedes mosquitoes. The preventive measures chosen by both
sub-distinct areas against mosquitobites were significantly affected by the biting time and the
mosquitoes biting frequency (P < 0.05).
Conclusions: In this study, we concluded that there is a direct link between the knowledge
of the Aedes biting frequency with dengue infection, human lifestyle on the light use and
preventive measures against mosquitoes. However, the level of knowledge is poor on the
subject of Aedes mosquitoes and dengue for both urban and sub-urban respondents