Tree adaptive growth (TAG) model: a life-history theory-based analytical model for post-thinning forest stand dynamics.

Background: Understanding stand dynamics is essential for predicting future wood supply and associated ecosystem services for sustainable forest management. The dynamics of natural stands can be characterized by age-dependent growth and yield models. However, dynamics in managed stands appear somewhat different from that of natural stands, especially with difficulties in explaining the phenomenon of post-thinning overcompensation, based upon some long-term observations.

Modelling the stand dynamics after a thinning induced partial mortality: A compensatory growth perspective.

Introduction: With increasing forest areas under management, dynamics of managed stands have gained more attention by forest managers and practitioners. Improved understanding on how trees and forest stands would respond to different disturbances is required to predict the dynamics of managed stand.s.

Detecting Compensatory Growth in Silviculture Trials: Empirical Evidence From Three Case Studies Across Canada.

Compensatory growth (CG) appears common in biology and is defined as accelerated growth after experiencing a period of unfavorable conditions. It usually leads to an increase in biomass that may eventually equal or even surpass that of sites not experiencing disturbance. In forestry, with sufficient time the stand volume lost in a disturbance such as a thinning operation could match or even exceed those from undisturbed sites, respectively called exact and overcompensation.

Ecology and Prediction of Compensatory Growth: From Theory to Application in Forestry.

Compensatory growth has been observed in forests, and it also appears as a common phenomenon in biology. Though it sometimes takes different names, the essential meanings are the same, describing the accelerated growth of organisms when recovering from a period of unfavorable conditions such as tissue damage at the individual level and partial mortality at the population level. Diverse patterns of compensatory growth have been reported in the literature, ranging from under-, to compensation-induced-equality, and to over-compensation.

Forest Productivity Enhancement and Compensatory Growth: A Review and Synthesis.

This review and synthesis article attempts to integrate observations from forestry to contemporary development in related biological research fields to explore the issue of forest productivity enhancement and its contributions in mitigating the wood supply shortage now facing the forest sector. Compensatory growth has been clearly demonstrated in the long-term precommercial thinning and fertilization trial near the Shawnigan Lake, British Columbia, Canada. This phenomenon appears similar to many observations from other biological fields.

State-dependent domicile leaving rates in Anopheles gambiae.

Background: Transmission of Plasmodium greatly depends on the foraging behaviour of its mosquito vector (Anopheles spp.). The accessibility of blood hosts and availability of plant sugar (i.

Impact of male alternative reproductive tactics on female costs of sexual conflict under variation in operational sex ratio and population density.

Sexual conflict over mating rate is both pervasive and evolutionarily costly. For females, the lifetime reproductive fitness costs that arise through interactions with potential mates will be influenced by the frequency of such interactions, and the fitness cost of each interaction. Both of these factors are likely to be influenced by variation in operational sex ratio (OSR) and population density.

State dependence, personality, and plants: light-foraging decisions in Mimosa pudica (L.).

Plants make foraging decisions that are dependent on ecological conditions, such as resource availability and distribution. Despite the field of plant behavioral ecology gaining momentum, ecologists still know little about what factors impact plant behavior, especially light-foraging behavior. We made use of the behavioral reaction norm approach to investigate light foraging in a plant species that exhibits rapid movement: Mimosa pudica.

Making the best of a bad situation: host partial resistance and bypass of behavioral manipulation by parasites?

With few exceptions, parasitic manipulation dramatically reduces host fitness. That said, evidence of host resistance to behavior-manipulating parasites is scarce. Here, we suggest that the evolution of partial resistance, as well as bypass, to manipulation (PRM and BPM, respectively) represents new, seldom-explored options for parasitized hosts.

Effects of food, water depth, and temperature on diving activity of larval Anopheles gambiae sensu stricto: evidence for diving to forage.

Anopheles gambiae larvae have frequently been observed to dive, but the ecology of this behavior has not been extensively examined. We manipulated food level, water depth, and temperature for individually-reared larvae and observed diving activity. Larvae dived more often under low food, which suggests that they dive to forage.

On the evolution of omnivory in a community context.

Omnivory is extremely common in animals, yet theory predicts that when given a choice of resources specialization should be favored over being generalist. The evolution of a feeding phenotype involves complex interactions with many factors other than resource choice alone, including environmental heterogeneity, resource quality, availability, and interactions with other organisms. We applied an evolutionary simulation model to examine how ecological conditions shape evolution of feeding phenotypes (e.

Effects of larval density and feeding rates on larval life history traits in Anopheles gambiae s.s. (Diptera: Culicidae).

Mosquito larval habitat determines the fitness, survivorship, fecundity, and vector capacity of emerging adults. We manipulated larval density and food provisioning in the laboratory to determine their effects on a number of life history parameters of Anopheles gambiae. Larval mortality was positively correlated with larval density.

Phenology of Dasineura oxycoccana (Diptera: Cecidomyiidae) on cranberry and blueberry indicates potential for gene flow.

Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) is a pest of cranberry, Vaccinium macrocarpon (Aiton) (Ericales: Ericaceae), and highbush blueberry, Vaccinium corymbosum (L.) (Ericales: Ericaceae), in North America. In British Columbia, Canada, D.

Energy-state dependent responses of Anopheles gambiae (Diptera: Culicidae) to simulated bednet-protected hosts.

In nature, Anopheles gambiae mosquitoes are found at various energy levels and such females must choose between seeking somatic energy from sugar sources and obtaining both somatic and gametic energy from blood hosts. We used a straight-tube olfactometer containing a simulated unobtainable blood host (human foot smell protected by a net) as well as a sugar source (honey odor). We assessed female probing rate and residence time at the net as a function of energy state (0, 24, 48, 72-h starved).

Predator identity and the nature and strength of food web interactions.

1. Most trophic interaction theory assumes that all predators are an abstract form of risk to which prey respond in a quantitatively similar manner. This conceptualization can be problematic because recent empirical work demonstrates that variation in the responses of prey to different predators can play a key role in structuring communities and regulating ecosystem function.

Host-adapted parasitoids in biological control: does source matter?

It has been hypothesized that the success of a biological control introduction is, in part, dependent on the ability of the control agent to become established in its new environment or to its new population of hosts through local adaptation. Despite this, few studies have investigated the influence of the recent coevolutionary history of pest species and natural enemies on the efficacy of biological control agents, especially for agents that are mass-reared for release in agriculture. We investigate the evolutionary potential of a biological control agent Aphidius ervi to adapt to a key pest species, the foxglove aphid Aulacorthum solani, through components essential to the evolution of parasitoid virulence.

Size-mediated adaptive foraging: a host-selection strategy for insect parasitoids.

Foraging models are useful tools for generating predictions on predator-prey interactions, such as habitat or diet choice. However, the majority of studies attempting to explain adaptive behaviour using optimality criteria have assumed that there is no trait (e.g.

Host-range evolution in Aphidius parasitoids: fidelity, virulence and fitness trade-offs on an ancestral host.

The diversity of parasitic insects remains one of the most conspicuous patterns on the planet. The principal factor thought to contribute to differentiation of populations and ultimately speciation is the intimate relationship parasites share with hosts and the potential for disruptive selection associated with using different host species. Traits that generate this diversity have been an intensely debated topic of central importance to the evolution of specialization and maintenance of ecological diversity.

Covariance of phenotypically plastic traits induces an adaptive shift in host selection behaviour.

Flexibility in adult body size allows generalist parasitoids to use many host species at a cost of producing a range of adult sizes. Consequently, host selection behaviour must also maintain a level of flexibility as adult size is related to capture efficiency. In the present study, we investigated covariance of two plastic traits--size at pupation and host size selection behaviour-using Aphidius ervi reared on either Acyrthosiphon pisum or Aulacorthum solani, generating females of disparate sizes.

The cost of being an omnivore: mandible wear from plant feeding in a true bug.

Evolutionary and ecological transitions from carnivorous to omnivorous feeding may be constrained by the ability of the animal to cope with disparate types of foods, even if preadaptations for such behaviour exist. The omnivorous true bug, Dicyphus hesperus (Hemiptera: Miridae) requires both animals (small, soft-bodied insects) and plants in its diet and obtains the majority of its dietary and metabolic water from plant feeding. Serrations on the lateral margins of the mandibular stylets wear with age, and this wear is exacerbated when the insects feed on plants compared to those provided free water and no plants.

Does the Anopheles blood meal-fecundity curve, curve?

We determined the blood meal size-fecundity relationship in Anopheles gambiae in the laboratory. Our primary interest was to determine whether the fecundity curve has a non-linear component, i.e.

Inclusive fitness benefits of scent-marking predators.

Because relatedness is high and dispersal is limited, one would expect to see higher levels of altruistic behaviour among clonal organisms than among animals of lesser relatedness. Enigmatically, however, parthenogenetic aphids do not emit alarm signals when a predator first enters a colony but only after being captured. Here, we report that an aphid smearing alarm pheromone directly onto a predator decreases the predation risk for clone-mates as the predator continues to search for additional prey.

(2R,7S)-diacetoxytridecane: sex pheromone of the aphidophagous gall midge, Aphidoletes aphidimyza.

In a recent study, evidence was presented that females of the aphidophagous midge Aphidoletes aphidimyza (Rondi) (Diptera: Cecidomyiidae) release a sex pheromone to attract mates. Our objectives were to identify and bioassay the pheromone. Coupled gas chromatographic-electroantennographic detection(GC-EAD) analyses of untreated and hydrogenated pheromone extract on three fused-silica columns (DB-5, DB-23, DB-210) revealed a single compound that elicited responses from male antennae.