scholarly journals The induction of larval resource preference in heterogeneous habitats

2018 ◽  
Vol 43 (6) ◽  
pp. 719-730
Author(s):  
Vrinda Ravi Kumar ◽  
Swastika Issar ◽  
Deepa Agashe
2018 ◽  
Author(s):  
Vrinda Ravi Kumar ◽  
Swastika Issar ◽  
Deepa Agashe

ABSTRACTAnimals often have to evaluate and choose between multiple food sources in their habitat, and these potentially complex decisions can have a large impact on their fitness. Among other factors, previous experience with an alternative resource can significantly increase subsequent preference for the resource ("induction of preference"). Such induction of resource preference is particularly relevant in spatially or temporally heterogeneous habitats. Although most mobile species – especially generalists – probably frequently encounter habitat heterogeneity, the impact of preference induction on individual behaviour and fitness in heterogeneous habitats is poorly understood. We analysed larval preference induction in wheat-adapted generalist red flour beetles (Tribolium castaneum) under three types of habitat heterogeneity. We first analysed the induction of larval preference for novel resources (other cereal flours) under temporal heterogeneity, exposing larvae to new resources during development. We found that larvae preferred a new resource if they experienced it recently, but that the magnitude of induction varied across resources. Interestingly, we also observed specific induction for a homogenous mix of wheat and a novel resource, with larvae preferring the mix over either pure resource. To analyse induction under spatial heterogeneity, we placed beetle eggs in one of two alternative resource patches and tested the preference of emerged larvae. Unexpectedly, hatching into a novel resource did not always induce preference. Finally, we found that induction of preference for new resources could be maladaptive for larval development. Together, our work demonstrates that experience-based plasticity of larval resource choice may strongly impact larval preference and fitness in heterogeneous habitats.


2008 ◽  
Vol 16 (1) ◽  
pp. 72-97 ◽  
Author(s):  
Haksin Chan ◽  
Lisa C. Wan

This article highlights consumers’ preference for economic (versus social) resources in individualist (versus collectivist) cultures and demonstrates the multifaceted effects of culture on consumer responses to service failures. A cross-cultural study involving American and Chinese participants in the setting of a computer repair service confirms seven of eight hypotheses derived from the resource preference model. The results indicate that Americans (versus Chinese) are more dissatisfied with an outcome failure but less dissatisfied with a process failure. This interactive effect of culture and failure type seems to be driven by a corresponding pattern of attribution tendencies across cultures. Not only do Americans and Chinese differ in service dissatisfaction, but they also tend to express their dissatisfaction in different ways, preferring voice and private responses, respectively. Overall, the resource preference model enhances theoretical understanding of cross-cultural consumer behavior and provides culture-specific guidelines for managing the inevitable service failures.


2014 ◽  
Vol 1010-1012 ◽  
pp. 121-125
Author(s):  
Wen Bin Li ◽  
Zhi Ming Mo ◽  
Xing Ting Chen ◽  
Chun Huang ◽  
Ming Feng Xu

To examine the impact of habitat heterogeneity on the bird communities, we investigated the structural differences of various bird communities occurring in heterogeneous habitats in the subtropical hilly areas of southern China. We used indicator Species Analysis (ISA) to test the association of specific bird species to particular habitats. We performed Two-way Cluster Analysis to find species patterning in response to habitat fragmentation. Our results demonstrated that heterogeneous habitats promoted bird diversity and human activities affected bird behavior. Indicator Species Analysis demonstrated that similar habitats had similar bird communities, while different habitats supported various bird indicator species. Although habitat diversity increased bird diversity of a region, it was unfavorable for the maintenance of specialized birds in the forests of the subtropical hilly area.


2002 ◽  
Vol 10 (3) ◽  
pp. 167-190 ◽  
Author(s):  
A S MacDougall ◽  
J A Loo

Habitat-directed survey methods are often used for locating narrowly distributed rare species and communities across landscapes, though their predictive accuracy varies, depending on the element targeted and the type of data employed. We discuss habitat-directed surveys for rare floral elements in the context of landscape-level management planning, focusing in particular upon a case study from southern New Brunswick. Databases of rare species and community occurrences are important requisites for such planning, but existing information is usually deficient and expensive to develop. A habitat-based approach directs surveys to sites with a higher-than-random probability of hosting rare elements and avoids areas deemed unlikely to be of interest due to environment or disturbance factors. We describe a four-part survey procedure that uses readily available qualitative habitat descriptions and geographic information systems (GIS) based land resource data to identify sites potentially hosting rare biota. The procedure includes remote-sensed and on-site screening to confirm significance and collect ancillary data needed for conservation planning. The use of existing data is cost and time efficient, a necessity given often narrow planning windows and restricted budgets. The method described here is well suited to geographically restricted plant biota associated with distinct habitats, especially in unsurveyed or highly fragmented landscapes. However, the approach does not apply to species of wide-ranging and environmentally heterogeneous habitats. As well, by targeting only highly specific locations assumed to be "optimal" habitat, the occurrence of rare biota in other areas cannot be definitively determined and some sites will almost certainly be missed. The limitations of the procedure highlight the need for multifaceted biodiversity assessment over large areas.Key words: ecosystem management, rare species, gap analysis, habitat-directed biodiversity survey, reserve network, New Brunswick.


2020 ◽  
Vol 12 (8) ◽  
pp. 15804-15816
Author(s):  
Kalyan Mukherjee ◽  
Ayan Mondal

Butterfly diversity was observed in different habitats of Bankura District, West Bengal, India.  This district is located at the junction of Chotanagpur plateau and Gangetic plain; it contains a variety of transitional habitats.  We found 117 butterfly species from our covered survey area.  The highest species recorded in the present study belonged to family Lycaenidae (30.76%) and Nymphalidae (29.91%) followed by Hesperiidae (16.23%), Pieridae (13.67%), Papilionidae (8.54%), and Riodinidae (0.85%), respectively.  Based on sighting we found that 12.82% of all the butterflies recorded were abundant in nature while 21.36% were very common, 41.88% were frequent, and 23.93% were rare. Cluster analysis and other diversity indices gives us an overall idea about environmental health.  The pattern of diversity change from plain to plateau gradient gives important insight about ecological edge effect.  High species number in relation with low individual numbers were found in forest habitat.  This preliminary study showed that heterogeneous habitats could harbour many butterflies and need proper conservation efforts to sustain it. 


2019 ◽  
Vol 46 (7) ◽  
pp. 613 ◽  
Author(s):  
Qing Wei ◽  
Qian Li ◽  
Yu Jin ◽  
Shulan Wu ◽  
Lihua Fan ◽  
...  

Previous studies have elucidated the mechanisms, ecological implications and constraints on transportation or sharing of defence signals among interconnected ramets of clonal plants suffering from localised herbivore damage. To our knowledge, few studies have been conducted to provide insights into the ecological implications on transportation or sharing of stress signals for clonal plants subjected to water stress. As a chemical elicitor, ABA can induce resistance response in plants suffering from water stress. A pot experiment was conducted to explore transportation or sharing of stress signals among interconnected ramets by using clonal fragments of Centella asiaticas (L.) Urban with four successive ramets (oldest, old, mature and young) subjected to low water availability (20% soil moisture contents). Compared with control, foliar oxidative stress of the old, mature and young ramets significantly decreased, and antioxidant capacity was increased when exogenous ABA was applied to the oldest ramets. Meanwhile, foliar PSII activity and chlorophyll content of the old, mature and young ramets significantly increased. Compared with control, biomass accumulation and ratio of below-ground/aboveground biomass of whole clonal fragments were significantly increased by ABA application to the oldest ramets. However, similar patterns were not observed when exogenous ABA was applied to the young ramets. Our results show that transportation or sharing of stress signals among interconnected ramets improves systemic resistance of clonal networks to water stress, which is dependent on directionality of vascular flows. Compared with the old or mature ramets, the young ramets displayed stronger resistance response (such as higher antioxidant enzymes activities and proline content, lower O2•− production rate and malondialdehyde content) to water stress as well as higher PSII activity and chlorophyll content when exogenous ABA was applied to the oldest ramets. Thus, transportation or sharing of stress signals may favour young ramets that are most valuable for growth and fitness of clonal plant subjected to environmental stress. It is suggested that transportation or sharing of stress signals among interconnected ramets may confer clonal plants with considerable benefits in adapting to spatio-temporal heterogeneous habitats.


2008 ◽  
Vol 32 (3) ◽  
pp. 277-291 ◽  
Author(s):  
George P. Malanson

The concept of the extinction debt has two components: a direct timelag between an environmental perturbation and the consequent extinction of a species and the idea that among species going extinct the strong competitors/weak colonizers go extinct first. Although the term was first used in 1994 in the context of metapopulation models, its roots go back to general systems theory and the theory of island biogeography. It has been qualified and elaborated since 1994, mostly in terms of the effects of spatial pattern on the outcomes. The strongest critiques of the concept emphasize that the direct trade-off between competition and colonization abilities is not simple. The original application was to remnant habitat patches, but it could be applied to spatially heterogeneous habitats that are subject to climate change or invasive species. As a guide to conservation practice, extinction debt remains a general cautionary principle rather than a specific prescription, but the raising of awareness is nevertheless significant.


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