Resource concentration hypothesis: effect of host plant patch size on density of herbivorous insects

Grez, Audrey A.; González, Roberto Herranz

doi:10.1007/bf00328685

Cited by 68 publications

(52 citation statements)

References 25 publications

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“…(1) First, the Natural Enemies hypothesis predicts that predator and parasitoid should be more abundant in polyculture than in monoculture because of the increased number of niches and resources available (Russell, 1989;Straub et al, 2014), (2). The resource concentration hypothesis states that pest species are attracted by plots where their host-plants are the most abundant (Grez & Gonzalez, 1995). These two mechanisms are complementary.…”

Section: Introductionmentioning

confidence: 99%

Coffee Production Systems: Evaluation of Intercropping System in Coffee Plantations in Rwanda

Harelimana¹,

Goff²,

Rukazambuga³

et al. 2018

JAS

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Intercropping is an agricultural practice consisting in planting two or several crops in the same field simultaneously. This production system appeared to offer an excellent several advantages. While intercropping has been widely practiced since ancestral times, there was a lack of data in Rwanda on the kind of intercrops mostly used and on farmers' perception of their utility and constraints. The main objectives of this work were (1) to assess the different food crops associated with coffee trees in Rwanda and (2) to determine the perception of farmers on the role of intercropping system. That was why a field survey was carried out between August 25 th , 2014 and February 28 th , 2015 in Kamonyi District of Rwanda. Seventy-five coffee producers were randomly selected and contacted to fill a questionnaire on their practices. The correlation between yield and pesticide application were performed using R version. The significance level P was set at 0.05. Results revealed that common beans (Pheseolus vulgaris L.) and soybeans (Glycine max L.) were the most coffee intercropped plants. It appeared that intercropping was practiced to ensure the production of staple crops beside coffee. Insecticide remained the main way to control coffee pests and there was thus an important work to find alternative solutions that are often ecologically non-disruptive. Plant breeders and extension agents should investigate plants that are suitable to intercrop with coffee trees in order to enhance the conservation agriculture.

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Section: Introductionmentioning

confidence: 99%

Coffee Production Systems: Evaluation of Intercropping System in Coffee Plantations in Rwanda

Harelimana¹,

Goff²,

Rukazambuga³

et al. 2018

JAS

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“…This last explanation appears to be the case in our study because galling insects can often disperse over long distances with the help of the wind (MENDONÇA-JR; ROMANOWSKI, 2002;LEITE et al, 2009). Moreover, because our study was a natural experiment in which we could not control the distance between sites a priori with different resource concentrations, the similarity of the insect attacks may have been caused by the proximity between the sites (CAPMAN et al, 1990;GREZ;GONZÁLEZ, 1995).…”

Section: Resultsmentioning

confidence: 90%

“…However, morphotypes 2 and 4 were not Thus, it is possible that the cecidomyiid insect dispersion determines the attack frequency on hosts at this site (GREZ; GONZÁLEZ, 1995). Grez and González (1995) propose some explanations for the lack of a relationship between insect attack and resource concentration: (i) insects with low dispersion can find sites with higher concentrations of resources because these locations are larger and would not leave these sites because is easy to find the resource and difficult to find the site boundary; and (ii) insects with a high dispersal ability can move easily between sites with different concentration of resources. In this way, the abundance of insects on a plant may be similar among hosts.…”

Section: Resultsmentioning

confidence: 99%

Gall-formig insect attack patterns: a test of the Plant Vigor and the Resource Concentration Hypotheses

Tuller

Queiroz

Luz³

et al. 2013

Biotemas

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ResumoPadrões de ataque de galhadores: um teste das hipóteses do vigor da planta e da concentração de recursos. Nós testamos duas hipóteses para investigar os padrões de ataque de insetos galhadores na planta hospedeira Eriotheca pubescens: (i) módulos mais vigorosos são mais atacados por insetos galhadores; (ii) indivíduos de E. pubescens em maiores densidades de indivíduos co-específicos possuem uma maior abundância de galhas. Nós coletamos ramos terminais da planta hospedeira para mensurar o comprimento dos seus módulos e a riqueza e abundância de galhadores. Nós determinamos a densidade de E. pubescens em um círculo com 5m de raio em torno do indivíduo focal. Houve uma maior disponibilidade de ramos curtos. Dentre os quatro morfotipos de galhas avaliados, dois preferiram ramos longos e outros dois não apresentaram preferência por um determinado tamanho de ramo. O ataque de galhadores não apresentou relação com a densidade de plantas hospedeiras. Então, o vigor da planta foi um fator determinante, para o ataque de galhas em E. pubescens. Por outro lado, a hipótese da concentração de recursos não foi importante em nível intra-específico para o ataque de galhas nesse sistema. Palavras-chave: Comprimento do módulo; Embiruçu; Eriotheca pubescens; Inseto galhador AbstractWe tested the following two hypotheses to investigate the attack patterns by gall-inducing insects on their host plant Eriotheca pubescens: (i) vigorous modules are more often attacked by galling insects; and (ii) E. pubescens trees associated with a higher density of co-specific individuals have a higher gall abundance. We collected terminal branches from the host plant to measure their module lengths and gall richness and abundance and determined the E. pubescens densities in a 5m radius around the focal individual. There was a higher availability of short branches. Among the four gall morphotypes, two preferred the higher branches, and the other two morphotypes had no shoot length preference. Gall attack did not present a relationship with the host plant density. Thus, the vigor of E. pubescens was a determining factor only for some gall morphotypes. In contrast, the resource concentration hypothesis was not important at an intraspecific level for gall attack in this system.

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“…The second hypothesis proposed by Root (1973) is the ''resource concentration hypothesis'': it predicts that specialist herbivorous insects should be more abundant in large patches of host plants. In experiments reported by Grez and Gonzalez (1995), this hypothesis proved to be highly dependent on which organism is studied: it is mainly a function of patch size and adult and juvenile dispersal behavior. Cereal aphids, due to their parthenogenic ability which allows rapid colonization (Simon et al 2002), are likely to be affected by the resources disruption created by tree rows in AF plots.…”

Section: Introductionmentioning

confidence: 94%

Unexpected lack of influence of tree rows on the dynamics of wheat aphids and their natural enemies in a temperate agroforestry system

2012

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Trees at low density and cereals may be combined in silvoarable agroforestry systems: tree rows and their companion vegetation introduce an heterogeneity in the cropped field that may modify the dynamics of insects crop pests and their predators. This hypothesis was tested in tree-wheat systems by monitoring aphids and their predators for two years in southern France, in two fields in 2006 and one in 2007. Tree row vegetation diversity was either suppressed by weeding or stimulated by seeding flowering species that could attract adult predators of aphids. The dynamics of aphids and predators were recorded by tiller sampling and yellow trap monitoring. Between 3500 and 5000 aphids were collected from each studied field. Surprisingly, no differences could be evidenced on the dynamics of both aphids and their predators between agroforestry and monocropping plots, nor between weeded and flowered plots. The heterogeneity induced by the tree row in the cropped field was probably not strong enough to alter the populations dynamics. A high landscape diversity in the area due to nearby forest patches and fallows may have blurred the impact of the tree lines. Different results may be expected in areas with lower biodiversity like cereal monocropping zones.

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Resource concentration hypothesis: effect of host plant patch size on density of herbivorous insects

Cited by 68 publications

References 25 publications

Coffee Production Systems: Evaluation of Intercropping System in Coffee Plantations in Rwanda

Coffee Production Systems: Evaluation of Intercropping System in Coffee Plantations in Rwanda

Gall-formig insect attack patterns: a test of the Plant Vigor and the Resource Concentration Hypotheses

Unexpected lack of influence of tree rows on the dynamics of wheat aphids and their natural enemies in a temperate agroforestry system

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