Fungal and Insect Parasites Contributing to Niche Differentiation in Mixed Species Stands of Eucalypt Saplings

1974 ◽  
Vol 22 (1) ◽  
pp. 103 ◽  
Author(s):  
JJ Burdon ◽  
GA Chilvers
Keyword(s):  
Leaf Area ◽  
Host Specificity ◽  
Host Preference ◽  
Niche Differentiation ◽  
Phytophagous Insects ◽  
Mixed Species ◽  
Area Loss ◽  
Fungal Parasites ◽  
Leaf Area Loss ◽  
Insect Parasites

Parasitic damage to the leading shoot of young regrowth eucalypts was found to vary considerably between trees and between different stands but it averaged greater than 20 % 'effective leaf area loss' overall. Many fungal parasites and some of the phytophagous insects responsible for this damage exhibited host specificity or host preference towards trees of a particular subgenus of Eucalyptus. These findings are discussed in relation to the hypothesis that parasites play an important role in the maintenance of stable associations between codominant species of Eucalyptus.

Abundance of leafminers and leaf area loss by chewing herbivores in hybrids between Quercus crispula and Quercus dentata

2004 ◽  
Vol 34 (12) ◽  
pp. 2501-2507 ◽  
Author(s):  
Takahide A Ishida ◽  
Kouhei Hattori ◽  
Masahito T Kimura
Keyword(s):  
Leaf Area ◽  
Parental Species ◽  
Quercus Crispula ◽  
Species Dominance ◽  
Area Loss ◽  
Early Instar ◽  
Sap Feeding ◽  
Leaf Area Loss ◽  
Quercus Dentata ◽  
Northern Japan

We examined responses of phytophagous insects to hybrids between Quercus crispula Blume and Quercus dentata Thunberg in a natural population in northern Japan. The abundance of leafminers and leaf area loss by chewing insects in hybrids were intermediate between those in the parental species (additive mode), close to those of either of the parental species (dominance mode), or similar to those of both parental species (no difference). Hybrids were neither more susceptible nor resistant to the insect herbivores we monitored. In Phyllonorycter (Gracillariidae) species, which are specialized to either of the parental oak species, the mortality of sap-feeding early instar larvae did not differ between hybrids and the parental species. The abundance of four leafminer taxa was correlated with environmental conditions (i.e., distance from the coastal edge of the forest or the timing of budbreak) as well as genetic factors.

scholarly journals Does insect herbivory suppress ecosystem productivity? Evidence from a temperate woodland

2021 ◽  
Author(s):  
Kristiina Visakorpi ◽  
Sofia Gripenberg ◽  
Yadvinder Malhi ◽  
Terhi Riutta
Keyword(s):  
Gas Exchange ◽  
Leaf Area ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Leaf Gas Exchange ◽  
Insect Herbivory ◽  
Ecosystem Productivity ◽  
Area Loss ◽  
Leaf Area Loss ◽  
The Relationship

AbstractOur current understanding of the relationship between insect herbivory and ecosystem productivity is limited. Previous studies have typically quantified only leaf area loss, or have been conducted during outbreak years. These set-ups often ignore the physiological changes taking place in the remaining plant tissue after insect attack, or may not represent typical, non-outbreak herbivore densities. Here, we estimate the amount of carbon lost to insect herbivory in a temperate deciduous woodland both through leaf area loss and, notably, through changes in leaf gas exchange in non-consumed leaves under non-outbreak densities of insects. We calculate how net primary productivity changes with decreasing and increasing levels of herbivory, and estimate what proportion of the carbon involved in the leaf area loss is transferred further in the food web. We estimate that the net primary productivity of an oak stand under ambient levels of herbivory is 54 - 69% lower than that of a completely intact stand. The effect of herbivory quantified only as leaf area loss (0.1 Mg C ha−1 yr−1) is considerably smaller than when the effects of herbivory on leaf physiology are included (8.5 Mg C ha−1 yr−1). We propose that the effect of herbivory on primary productivity is non-linear and mainly determined by changes in leaf gas exchange. We call for replicated studies in other systems to validate the relationship between insect herbivory and ecosystem productivity described here.

Mechanisms promoting recovery from defoliation in goldenrod (Solidago altissima)

1998 ◽  
Vol 76 (3) ◽  
pp. 450-459 ◽  
Author(s):  
G A Meyer
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Unit Area ◽  
Total Carbon ◽  
Carbon Gain ◽  
Solidago Altissima ◽  
Photosynthetic Rates ◽  
Area Loss ◽  
Compensatory Photosynthesis ◽  
Leaf Area Loss

Plant responses to defoliation were examined using Solidago altissima and a leaf-chewing beetle (Trirhabda sp.). Plants were exposed to five intensities of defoliation (ranging from 0 to 85% leaf area loss) and effects on carbon gain, vegetative growth, and flowering were determined. Defoliated plants partially restored their capacity for carbon gain in the following ways: (i) activity of damaged leaves remaining after defoliation was increased via delayed senescence and enhanced photosynthetic rates and (ii) regrowth leaves on damaged plants had higher specific leaf area (leaf area per leaf mass) than comparable leaves on undamaged plants, but photosynthetic rates per unit area were equivalent to controls; thus, these leaves covered more area for a given investment in biomass with no loss in activity per unit area. Delayed leaf senescence and compensatory photosynthesis are commonly observed following defoliation, but increased specific leaf area is not generally recognized as a mechanism contributing to plant regrowth. In spite of these changes, total carbon gain capacity of defoliated plants was still less than that of controls after 3 weeks of regrowth. Overall plant performance was reduced by defoliation. Defoliated stems grew at a slower rate early in the season, added fewer new leaves in the first few weeks after defoliation, and had fewer lateral stems throughout the season. Damaged plants delayed flowering and maintained height growth later into the season than undamaged plants. Damaged stems reached heights comparable with undamaged stems by the end of the season, but they were thinner and their flower production was lower. Declines in plant growth and flowering were linear functions of the percentage leaf area loss, suggesting that even low levels of insect feeding are likely to affect plant performance.Key words: Solidago altissima, Trirhabda, defoliation, compensatory photosynthesis, insect herbivory, herbivore damage, plant compensation.

scholarly journals Vegetative Flush Development and Leaf Area Contribution to Citrus Canopies

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 770C-770
Author(s):  
L. Gene Albrigo
Keyword(s):  
Leaf Area ◽  
Growing Season ◽  
Time Interval ◽  
Total Leaf Area ◽  
Citrus Leafminer ◽  
Area Loss ◽  
Total Leaf ◽  
Florida Citrus ◽  
Leaf Area Loss

The recent infestation of Florida citrus by the Asian citrus leafminer required that more information be obtained about the time interval for a flush to expand and the leaf area contributed by flushes in seasons when leafminer populations are likely to increase and cause leaf area loss. Time for leaf and shoot expansion was determined for spring and summer flush. Leaf area contribution from previous-year and current flushes was determined by seasonal tagging and measuring leaf area for flush in frame areas of 1/4 m2 surface projected to the center of the tree. Flush of 1/3 m length required 30 days to expand from first leaf feathers to full expansion. Summer flush in 1994 was 40% to 45% of total leaf area. Spring and previous year's flush averaged 20% each. Fall flush contributed 5% to 12% to leaf area, more on young, low-bearing trees. Summer flush resulted in more canopy leaf area and previous year's flushes less leaf area than expected by the end of the growing season.

Effects of light intensity and artificial wounding on monoterpene production in Myrica cerifera from two different ecological habitats

2004 ◽  
Vol 82 (10) ◽  
pp. 1501-1508 ◽  
Author(s):  
Min Wang ◽  
David E Lincoln
Keyword(s):  
Light Intensity ◽  
Leaf Area ◽  
Glandular Trichomes ◽  
Significant Negative Correlation ◽  
High Light Intensity ◽  
Physical Factors ◽  
Myrica Cerifera ◽  
Area Loss ◽  
Leaf Area Loss ◽  
Artificial Wounding

The contributions of multiple factors to plant defense and herbivory in different habitats has received limited study. This study examines the contributions of genotypic differentiation and modification by physical factors to chemical defense and herbivory of Myrica cerifera L. in contrasting habitats. The constitutive leaf monoterpene content of M. cerifera was higher in a sunny habitat than in an adjacent shady habitat at a southeastern USA coastal site. Leaf area loss was higher in the shady habitat than in the sunny habitat. A significant negative correlation of monoterpene content and leaf area loss suggests that monoterpenes may play toxic or deterrent roles in these plants. When plants from the two habitats were grown under uniform greenhouse conditions, the contents and compositions of leaf monoterpenes were not significantly different, implying that two ecotypes were not involved. The plants treated in high light intensity had significantly higher monoterpene content, higher growth rate, and denser glandular trichomes than the plants treated in low light intensity. Artificial wounding induced a significant increase of monoterpene production. However, the wounding responses of the plants from the two habitats were not different, nor did irradiance modify the response.Key words: ecotype, herbivory, light intensity, monoterpenes, wounding induction, Myrica cerifera.

Herbivory on planted dipterocarp seedlings in secondary logged forests and primary forests of Sabah, Malaysia

2001 ◽  
Vol 17 (2) ◽  
pp. 285-302 ◽  
Author(s):  
BRUCE E. HOWLETT ◽  
DIANE W. DAVIDSON
Keyword(s):  
Leaf Area ◽  
Interspecific Variation ◽  
Leaf Expansion ◽  
Leaf Damage ◽  
Primary Forest ◽  
Secondary Forests ◽  
Mature Leaves ◽  
Area Loss ◽  
Expansion Time ◽  
Leaf Area Loss

Leaf defences, leaf nutritional quality and leaf expansion rates may vary with resource availabilities to plants. Such variation could affect rates of leaf loss to herbivores, particularly along the steep resource gradients in disturbed forests. Intraspecific and interspecific variation in leaf damage and leaf expansion rates were measured on dipterocarp seedlings planted into secondary forests 1, 5 and 15 y after logging, and in adjacent primary forest of Sabah, Malaysia. Herbivory rates or amounts of leaf damage were compared across habitats and species for expanding, recently expanded, and mature leaves of Shorea leprosula and Dryobalanops lanceolata (Dipterocarpaceae). In all four habitats, leaves of the faster growing S. leprosula sustained higher rates and amounts of leaf-area loss than did the tougher leaves of slower growing D. lanceolata. Expanding leaves accumulated more leaf-area loss per week than did mature leaves. In all habitats and in both species, more than 25% of expanding leaves disappeared entirely. Rates of leaf-area loss per week differed among habitats for expanding leaves but not for mature leaves. In a relatively open, 1-y-old logged forest, faster leaf expansion reduced the time leaves spent in the most vulnerable stage; however, in S. leprosula a greater rate of leaf area loss countered the shorter expansion time. Thus, leaves accumulated similar total damages across habitats, and herbivory did not produce differences among habitats in seedling growth or mortality. High levels of resources may increase both leaf palatability and leaf expansion rates, with counteracting effects on herbivory.

Host specificity of Argulus coregoni (Crustacea: Branchiura) increases at maturation

Parasitology ◽  
2007 ◽  
Vol 134 (12) ◽  
pp. 1767-1774 ◽  
Author(s):  
V. N. MIKHEEV ◽  
A. F. PASTERNAK ◽  
E. T. VALTONEN
Keyword(s):  
Host Specificity ◽  
Host Preference ◽  
Oxygen Depletion ◽  
Host Choice ◽  
Fish Host ◽  
Argulus Foliaceus ◽  
Argulus Coregoni ◽  
Suitable Habitats ◽  
Fish Hosts ◽  
Higher Sensitivity

SUMMARYWe tested the hypothesis that host specificity in ectoparasites does not depend exclusively on the features of the host but also on surrounding habitats, using 2 fish ectoparasites, Argulus coregoni and A. foliaceus (Crustacea: Branchiura), occurring sympatrically in Finnish lakes. Although these parasites are considered to be of low specificity, we found that the larger of the 2 species, A. coregoni developed a pronounced preference for salmonid hosts at the beginning of maturation (defined by the presence of copulating specimens). Argulus foliaceus infects a much wider range of fish hosts. We showed that specialization of A. coregoni on salmonids does not necessarily result from incompatibility with other fishes, but could instead reflect higher sensitivity of oxygen depletion compared with A. foliaceus. Adult A. coregoni may meet these demands by attaching to salmonids, the typical inhabitants of well-aerated waters. Young parasites of both species showed little host specificity and attached mainly to fishes with higher body reflectivity. In host choice experiments, A. coregoni of 4–5 mm length preferred salmonids (rainbow trout) to cyprinids (roach) irrespective of the type of fish host, on which it had been previously grown in the laboratory. We suggest that such an innate ontogenetic shift in host preference maintains the major part of the parasite population on its principal host, ensuring successful reproduction within suitable habitats.

scholarly journals Testing Host-Plant Driven Speciation in Phytophagous Insects: A Phylogenetic Perspective

2019 ◽  
Author(s):  
Emmanuelle Jousselin ◽  
Marianne Elias
Keyword(s):  
Host Plant ◽  
Evolutionary Biology ◽  
Phylogenetic Analyses ◽  
Evolutionary Process ◽  
Niche Differentiation ◽  
Ecological Speciation ◽  
Model Systems ◽  
Phytophagous Insects ◽  
Ecological Specialization ◽  
Recent Developments

During the last two decades, ecological speciation has been a major research theme in evolutionary biology. Ecological speciation occurs when reproductive isolation between populations evolves as a result of niche differentiation. Phytophagous insects represent model systems for the study of this evolutionary process. The host-plants on which these insects feed and often spend parts of their life cycle constitute ideal agents of divergent selection for these organisms. Adaptation to feeding on different host-plant species can potentially lead to ecological specialization of populations and subsequent speciation. This process is thought to have given birth to the astonishing diversity of phytophagous insects and is often put forward in macroevolutionary scenarios of insect diversification. Consequently, numerous phylogenetic studies on phytophagous insects have aimed at testing whether speciation driven by host-plant adaptation is the main pathway for the diversification of the groups under investigation. The increasing availability of comprehensive and well-resolved phylogenies and the recent developments in phylogenetic comparative methods are offering an unprecedented opportunity to test hypotheses on insect diversification at a macroevolutionary scale, in a robust phylogenetic framework. Our purpose here is to review the contribution of phylogenetic analyses to investigate the importance of plant-mediated speciation in the diversification of phytophagous insects and to present suggestions for future developments in this field.

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