Does plant diversity increase top-down control of herbivorous insects in tropical forest?

Oikos ◽  
2017 ◽  
Vol 126 (8) ◽  
pp. 1142-1149 ◽  
Author(s):  
Bruno Leles ◽  
Xue Xiao ◽  
Bonifacio O. Pasion ◽  
Akihiro Nakamura ◽  
Kyle W. Tomlinson
Ecology ◽  
2017 ◽  
Vol 99 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Brandon T. Barton ◽  
Oswald J. Schmitz

2007 ◽  
Vol 7 ◽  
pp. 123 ◽  
Author(s):  
Keshab Shrestha

Lying at western corner of the Kathmandu city, the Swoyambhu hillock (1403.76m) represents a surviving pristine forest in the metropolitan capital of Nepal. Once an extension of Jamaca (2096m) with luxuriant sub-tropical forest is now invaded by dense human population and other developmental activities. This hillock is still rich with a total plant species of 319. Of them, 65 are trees, 43 shrubs, 194 herbs and 17 climbers. Northern slope of the hillock is rich in tree species with scattered patches of under-growing bushes and ferns, whereas southern, western and eastern slopes are much disturbed with exotic species of plants, creating challenges to the norms of the heritage standard. Domination by Pinus roxburghii (chire pine) and Eucalyptus, Jacaranda and Callistemon, etc are altering the indigenous nature of the hillock. And also the forested hillock has been randomly utilized for refreshment, yoga, ayurbedic remedy and food. Due to growing constructions and exploitations, the forested hillock is now facing a threat to maintain its pristine ecosystem. <i>Nepal Journal of Science and Technology</i> Vol. 7, 2006


Author(s):  
Jaboury Ghazoul

‘Simple complex questions’ contrasts top-down and bottom-up approaches to ecological puzzles. For example, plants evade herbivores with physical defences that render them toxic or unpalatable, and the predators then evolve their own defences. How can a tropical forest support over 1,000 different tree species in a 50-hectare plot? When trees in the same forest differ in their response to environmental changes, can we still describe their environment as a niche? In species-rich systems, is there stability in complexity? Do we need so many species? Even when answering this question, we might benefit from a less human-centred approach. Earth’s biological richness has resonance beyond the dominant species.


Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 648
Author(s):  
Rebecca Nestle ◽  
Jaret C. Daniels ◽  
Adam G. Dale

Monarch butterfly populations have declined by over 80% in the last 20 years. Conservation efforts focus on the creation of milkweed habitats to mitigate this decline. Previous research has found monarchs lay more eggs per milkweed stem in urban gardens than natural habitats and recent work identified specific garden designs that make urban gardens more attractive to monarchs. Increasing plant diversity can reduce specialist insect herbivore colonization via bottom-up (e.g., plant) and top-down (e.g., predation) regulatory factors. Although this is beneficial for pest management efforts, it contradicts conservation efforts. In this study, we explored if adding multiple flowering species to garden-sized milkweed plantings affected monarch oviposition or top-down regulation of larvae. We compared monarch egg abundance, natural enemy abundance and richness, and biological control of monarch larvae in milkweed monocultures and milkweed mixed with four additional wildflower species. We found that monarchs laid 22% more eggs on sentinel milkweed plants in mixed-species plots with no effect of plant diversity on monarch survival. We also found higher natural enemy richness, wasp, and predatory bug abundance in the mixed-species plots and this did not translate to higher biological control rates. Our results provide more evidence that plant selection and habitat design are important for monarch conservation.


2018 ◽  
Vol 29 (4) ◽  
pp. 704-714 ◽  
Author(s):  
Handanakere S. Dattaraja ◽  
Sandeep Pulla ◽  
Hebbalalu S. Suresh ◽  
Mavinakoppa S. Nagaraja ◽  
Chilakunda A. Srinivasa Murthy ◽  
...  

Nature ◽  
2002 ◽  
Vol 416 (6883) ◽  
pp. 841-844 ◽  
Author(s):  
Vojtech Novotny ◽  
Yves Basset ◽  
Scott E. Miller ◽  
George D. Weiblen ◽  
Birgitta Bremer ◽  
...  

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