The Numerical Responses of Insect Predators to Changes in Prey Density

Crawley, Michael J.

doi:10.2307/3725

Cited by 43 publications

(26 citation statements)

References 37 publications

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“…One measure of a predator's physiological state is its body weight (Anderson 1974;Tanaka and Ito 1982;Matsura 1981). Predators that attack prey more frequently, in general, are heavier, lay more eggs, and develop faster than predators that attack prey less frequently (Crawley 1975;Hassell 1978;Eberhard 1979;Baumgaertner et al 1981;Lenski 1984). Predators that attack prey more frequently, in general, are heavier, lay more eggs, and develop faster than predators that attack prey less frequently (Crawley 1975;Hassell 1978;Eberhard 1979;Baumgaertner et al 1981;Lenski 1984).…”

Section: Introductionmentioning

confidence: 99%

ALLOZYME SURVEY AND RELATIONSHIPS OFLIMNOPORUSSTÅL SPECIES (HETEROPTERA: GERRIDAE)

Sperling

Spence

1990

Can Entomol

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Can. Enr. 122: 285-294 (1990) Body weights were measured for Podisus maculiventris (Say) (Heteroptera: Pentatomidae) given low prey inputs. Predators were fed green bean slices ad lib and a single mealworm larva (Tenebrio molitor L.) of one of two size classes, for a 24-h period every 1, 2 , 4 , 8, or 16 days. Other treatments included predators fed to excess of daily attacks, predators given only green bean slices, and predators given no food. Results showed that predators fed bean slices maintained body weight after an initial decline, whereas predators given no food lost weight continually until death. Predators maintained weight when fed prey ad lib, and when fed prey of either size daily. Those fed at longer intervals lost weight between feedings, and weight fluctuations increased as the interfeeding interval increased. Slopes of weight change between feedings did not differ significantly for predators fed at 2-through 16-day intervals. During oviposition, predators lost about 15 mg of body weight. Egg clutches comprised about 60% of the weight lost. Egg weights did not differ among treatments. The results suggest that P. maculiventris can survive long periods without prey, and adjusts its weight loss by reducing reproductive effort when prey become scarce. The importance of these adaptations for P. maculiventris to sustain populations in agricultural systems is discussed.La masse corporelle de Podisus maculiventris (Say) (Heteroptera: Pentatomidae) a kt6 dktenninke pour des individus nourris d'une faible quantitk de proies. Pour une pkriode de 24 h, 2 tous les 1, 2, 4, 8 et 16 jours, les prkdateurs ont kt6 nourris volontk de tranches de haricot vert et d'une grosse ou d'une petite chenille de Tenebrio molitor (L.). Dans d'autres traitements, les praateurs ont kt6 nourris d'un excks de grosses chenilles de T. molitor ou de tranches de haricot vert seulement ou n'ont r e~u aucune nourriture. Les prkdateurs nourris de haricots ont initiallement perdu du poids mais ont par la suite maintenu leur masse corporelle, alors que ceux auxquels on a refusk accbs a la nourriture ont perdu du poids continuellement jusqu'a la mort. Les prkdateurs noums d'un excbs de grosse chenilles ainsi que ceux nourris joumalikrement d'une petite ou d'une grosse chenille ont maintenu leur poids. Par contre, lorsque l'intewalle entre chaque repas a kt6 plus long, il y a eu perte de poids entre les repas, et cette perte s'est accentuke avec la d u r k des intervalles. Nkanmoins, les niveaux de variation de poids (pentes des rkgressions) n'ont pas kt6 significativement diffkrents pour des intervalles de 2 a 16 jours. Pendant la ponte, les prkdateurs ont perdu environ 15 mg de masse corporelle dont 60% est imputable a la masse des oeufs pondus. La masse des oeufs n'a pas diffkrk entre les traitements. Les rksultats suggkrent que P. maculiventris peut survivre longtemps sans proie et peut compenser pour sa perte de poids en rkduisant son effort reproducteur lorsque les proies deviennent rares. L'importance de ces adaptations pour le main...

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Section: Introductionmentioning

confidence: 99%

ALLOZYME SURVEY AND RELATIONSHIPS OFLIMNOPORUSSTÅL SPECIES (HETEROPTERA: GERRIDAE)

Sperling

Spence

1990

Can Entomol

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“…Crawley, 1975;Turchin et al, 1999;Abrams & Ginsburg, 2000;Lombaert et al, 2006). They found that predation risk affects prey behaviour and leads to avoidance and dispersal of the prey (Jeffries & Lawton, 1984, Berdegue et al, 1996recently, Skelhorn et al, 2011;Gonthier, 2012).…”

Section: Introductionmentioning

confidence: 99%

Key factors affecting the predation risk on insects on leaves in temperate floodplain forest

Drozdová¹,

Šipoš²,

Drozd³

2013

Eur. J. Entomol.

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Abstract. The predation on insects on leaves was measured by direct observation using live larvae of Calliphora vicina (Diptera: Calliphoridae) as bait placed on 15 common species of woody plants in a floodplain forest in the temperate region. The predation rate was measured in terms of the proportion of the larvae that were missing or had been attacked after 30 min of exposure on leaves. Despite the fact that the important predators differed during the course of a season, the most frequently recorded predators were birds and ants and less frequently recorded wasps and spiders. Analysis of the pattern in the distribution of the attacks confirmed that it is best described by a negative binomial distribution, which corresponds to a clumped dispersal of predation. Based on the results of the best-fitted generalized additive model, we could not reject an equal probability of attacks on the different species of woody plants. Further, predation at the forest edge was notably higher than in the forest interior. The model also predicted marked variations in the incidence of attacks during the course of a day and a season, with the attacks occurring mainly in three periods during the year and two during the day. In general, the sampling method used could become the standard measure of the risk of insects living on trees being attacked by predators in future studies.

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“…In contrast, the density-dependant deaths are represented as the second-order decay processes to represent competitive deaths and carrying capacity of the environment (DeAngelis, 1992;Malchow, 2000). A Holling Type III function is used to represent fish (F G ) feeding on invertebrates (Z G ), and all other feeding processes are represented by Type II functions (Holling, 1959;Cushing, 1959Cushing, , 1968Crawley, 1973;Taylor, 1984;DeAngelis, 1992). Since F G is a constant model parameter, Type III function makes the F G À Z G interaction to depend mainly on invertebrate concentration, corresponding to fish ingesting more during high invertebrate availability and using internal fat cells to maintain the constant fish concentration during Z G scarcity (Malchow, 2000;Malchow et al, 2001).…”

Section: Two-zone Modelmentioning

confidence: 99%

Two-zone model for stream and river ecosystems

2009

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A mechanistic two-zone model is developed to represent the food web dynamics of stream and river ecosystems by considering the benthic and nonbenthic (or water-column) zones as two separate, but interacting biotopes. Flow processes, solar radiation, and temperature are the dynamic external environmental drivers. State variables are defined to represent the hierarchical levels of detritus, limiting nutrient, vegetation, and invertebrates. The fish trophic level is included as a constant input parameter. Model parameters, constants, and boundary conditions are defined based on watershed as well as channel hydrology, stream geomorphology, and biological activities. Recent advances in ecological science and engineering are used in representing important biogeochemical processes. In particular, the turbulent diffusion, as well as sloughing or detachment, processes are defined based on these recent advancements. The two-zone model was evaluated for a gravel bed prealpine Swiss stream named River Necker with data for the study period of January 1992 through December 1994. The model was able to capture the general trends and magnitudes of the food web state variables. A comprehensive relative sensitivity analysis with five momentbased measures found that approximately 5% of the model parameters were important in predicting benthic vegetation. Results of sensitivity analysis guided the model calibration. Simulated benthic vegetation with the calibrated model, which was obtained by adjusting only four parameters, corresponded with observed data. Hydrology-dependent sloughing and detachment were dominant in determining the response of benthic vegetation and invertebrates. The proposed two-zone food web model is a potentially useful research tool for stream and river ecosystems. Electronic supplementary material The online version of this article (

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The Numerical Responses of Insect Predators to Changes in Prey Density

Cited by 43 publications

References 37 publications

ALLOZYME SURVEY AND RELATIONSHIPS OFLIMNOPORUSSTÅL SPECIES (HETEROPTERA: GERRIDAE)

ALLOZYME SURVEY AND RELATIONSHIPS OFLIMNOPORUSSTÅL SPECIES (HETEROPTERA: GERRIDAE)

Key factors affecting the predation risk on insects on leaves in temperate floodplain forest

Two-zone model for stream and river ecosystems

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