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

Oecologia ◽  
1995 ◽  
Vol 103 (4) ◽  
pp. 471-474 ◽  
Author(s):  
A. A. Grez ◽  
R. H. Gonz�lez
Revista CERES ◽  
2017 ◽  
Vol 64 (2) ◽  
pp. 143-150
Author(s):  
Marcela de Castro Nunes Santos Terra ◽  
Rubens Manoel dos Santos ◽  
Warley Augusto Caldas Carvalho ◽  
Polyanne Aparecida Coelho ◽  
Geovany Heitor Reis ◽  
...  

ABSTRACT Galls are the result of a specific interaction between an inducer and a host plant. The species Heteropterys byrsonimifolia A. Juss. occurs in abundance in semideciduous seasonal forest ecotones and adjacent open formations. In the ecological reserve Quedas do Rio Bonito, located in the state of Minas Gerais, Brazil, this species is affected by a single gall morphotype. The present study aimed to evaluate whether the structural complexity of the host (test of the structural complexity hypothesis) and the distance between hosts (test of the resource concentration hypothesis) affect gall density in H. byrsonimifolia and to characterize the spatial distribution of the infestation. The results corroborate the two hypotheses tested, suggesting a metapopulation pattern of gall infestation in H. byrsonimifolia. Gallers were more successful in abrupt forest-savannah transition environments, which may be associated with greater stress-induced host vulnerability that plants usually experience in ecotones.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Belén Cotes ◽  
Gunda Thöming ◽  
Carol V. Amaya-Gómez ◽  
Ondřej Novák ◽  
Christian Nansen

AbstractRoot-associated entomopathogenic fungi (R-AEF) indirectly influence herbivorous insect performance. However, host plant-R-AEF interactions and R-AEF as biological control agents have been studied independently and without much attention to the potential synergy between these functional traits. In this study, we evaluated behavioral responses of cabbage root flies [Delia radicum L. (Diptera: Anthomyiidae)] to a host plant (white cabbage cabbage Brassica oleracea var. capitata f. alba cv. Castello L.) with and without the R-AEF Metarhizium brunneum (Petch). We performed experiments on leaf reflectance, phytohormonal composition and host plant location behavior (behavioral processes that contribute to locating and selecting an adequate host plant in the environment). Compared to control host plants, R-AEF inoculation caused, on one hand, a decrease in reflectance of host plant leaves in the near-infrared portion of the radiometric spectrum and, on the other, an increase in the production of jasmonic, (+)-7-iso-jasmonoyl-l-isoleucine and salicylic acid in certain parts of the host plant. Under both greenhouse and field settings, landing and oviposition by cabbage root fly females were positively affected by R-AEF inoculation of host plants. The fungal-induced change in leaf reflectance may have altered visual cues used by the cabbage root flies in their host plant selection. This is the first study providing evidence for the hypothesis that R-AEF manipulate the suitability of their host plant to attract herbivorous insects.


Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley

Abstract For herbivorous insects, dropping from the host plant is a commonly-observed antipredator defence. The use of dropping compared to other behaviours and its timing in relation to contact with a predator was explored in both pea aphids (Acyrthosiphon pisum) and potato aphids (Macrosiphum euphorbiae). Pea aphids dropped more frequently in response to ladybird adults (Adalia bipunctata) than lacewing larvae (Chrysoperla carnea). Potato aphids mainly walked away or backed-up in response to both predator types; but they dropped more frequently relative to other non-walking defences when faced with ladybird adults. Contact with a predator was an important influencer of dropping for both species, and most drops occurred from adjacent to the predator. Dropping appears to be a defence adaptively deployed only when the risk of imminent predation is high; factors that increase dropping likelihood include presence of faster-foraging predators such as adult ladybirds, predator proximity, and contact between aphid and predator.


2019 ◽  
Vol 28 (2) ◽  
pp. 21-26
Author(s):  
Ming Kai Tan ◽  
Hui Lee ◽  
Hugh Tiang Wah Tan

Distribution of consumers in a patch of vegetation can be predicted by resource availability and explained by the resource-concentration and optimal-foraging hypotheses. These hypotheses have not been explored for flower-visiting Orthoptera because they are deemed less economically or ecologically important. Some flower-visiting orthopterans can provide pollination services, which warrants more attention. We studied a Singaporean, floriphilic katydid, Phaneropterabrevis, to investigate the following questions: 1) how frequently does P.brevis visit flowers compared to other flower visitors and 2) what factors predict the abundance of P.brevis? We collected abundance data for P.brevis and other flower-visiting arthropods and quantified seven environmental parameters, including flower abundance and host-plant species richness. We found that P.brevis frequents flowers significantly more often than some common and expected flower visitors such as hoverflies. In line with the prediction of the resource-concentration hypothesis, the abundance of P.brevis was positively correlated with a higher flower abundance. Owing to the limited information on unexpected wild flower visitors and pollinators, especially from the understudied tropics of Southeast Asia, we propose that P.brevis can be a model organism for future studies to answer fundamental questions on flower visitation.


2014 ◽  
pp. 197-233 ◽  
Author(s):  
Heiko Vogel ◽  
Richard O. Musser ◽  
Maria de la Paz Celorio-Mancera

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