Energy Acquisition and Allocation in Plants and Insects: A Hypothesis for the Possible Role of Hormones in Insect Feeding Patterns

Abstract

Can. Ent. 119: 109-129 (1987) A distributed delay age structure model is presented for plants and insects that describes the dynamics of per capita energy (dry matter) acquisition and allocation patterns, and the within-organism subunit (e.g. leaves, fruit, ova) number dynamics that occur during growth, reproduction, and development. Four species of plants (common bean, cassava, cotton, and tomato) and two species of insects (pea aphid and a ladybird beetle) are modeled. A common acquisition (i.e. functional response) submodel is used to estimate the daily photosynthetic rates in plants and consumption rates in pea aphid and the ladybird beetle. The focus of this work is to capture the essence of the common attributes between trophic levels across this wide range of taxa. The models are compared with field or laboratory data. A hypothesis is proposed for the observed patterns of reproduction in pea aphid and in a ladybird beetle. RCsumeOn a construit un modele dkmographique avec distribution de dklai applicable ? I des plantes et des insectes. Le modele dkcrit la dynarnique de l'appropriation et de la rkpartition de I'knergie (matiere seche) per capita, et la dynamique des nombres des sous-unites inm-organisme (ex. feuilles, fruits, oeufs). On a ainsi modklist quatre sortes de plantes {Eve, cassava, coton et tomate) et deux espkes d'insectes (puceron du pois et coccinelle). On utilise un sous-modcle comrnun d'acquisition (rdsponse fonctionnelle) pour estimer les vitesses journali&res de photosynthkse des plantes et d'alimentation du puceron et de la coccinelle. Le but de ce travail est d'extraire les caractkristiques essentielles communes aux niveaux trophiques occup6s par ces divers taxons. Les modkles sont compares avec des donnkes de terrain et de laboratoire. On propose une hypothese pour expliquer les profils obsew6s de reproduction du puceron du pois et de la coccinelle.

The dynamics of grape leafhopperEmpoasca vitisGöthe populations in southern Switzerland and the implications for habitat management

“…vitis populations. Time-distributed delay models have found a wide application in phenology and agreoecosystem analyses (Manetsch, 1976;Welch et al, 1978;Gutierrez et al, 1984Gutierrez et al, , 1987. The time-varying distributed delay model with attrition (Vansickle, 1977) was found particularly appropriate to simulate the dynamics of plant components and insect populations Severini et al, 1990aSeverini et al, , 1990b.…”

“…The theory on poikilothermic development as well as the observations of Vidano et al ( 1958) and Arzone et al (1988) stress the importance of abiotic factors, such as temperature, and biotic factors, particularly parasitoids, in the dynamics of E. vitis. Selection of the appropriate model relies on the theoretical considerations by Severini et al (1990a,b) and on the casestudies of Gutierrez et al (1984Gutierrez et al ( , 1987. The estimation of the parameters of the model requires detailed experiments under controlled conditions and in the field which, for the species under study, have already been described elsewhere (Cerutti et al, 1990).…”

An ecosystem analysis of spider mite outbreaks: physiological stimulation or natural enemy suppression

“…Although models only mimic reality, they are useful for studying interactions of populations across one or more trophic levels for a large range of scenarios. By modifying selected parameters individually or in combination, and by contrasting simulation results with those obtained from the more restricted field experiments, simulation models allow increased insight into the cotton agroecosystem (see Blood and Wilson, 1978;Gutierrez et al, 1984Gutierrez et al, , 1987Gutierrez and Regev, 1983;Stone et at., 1986).…”

Elements for modelling the dynamics of tritrophic population interactions

“…3.875 (Gutierrez et al, 1987(Gutierrez et al, , 1988; s, search rate of photosynthetically active organs calculated from DeBeer's law fbr a single tree (, Jackson and Palmer, 1979); r, reserves (30% of the weight of a tree at the beginning of the growing season, see Priestley, 1960 ), weight differs according to rootstock and cultivar (Miiller, 1976); and B, demand for carbohydrates by various tree organs j (leaves, shoots, fruits, roots, perennial frame and reserves): The carbohydrates available (S, Equation (5)) are distributed according to a scheme that satisfies respiration costs first and gives priority to fruits over leaves, shoots and secondary growth; these are more attractive sinks than roots and reserves . If demand exceeds supply, the growth of plant organs is reduced.…”

“…Both models require knowledge on the temperature profile T(t), which is generally difficult to represent accurately (Curry and Feldman, 1987). In the models of Gutierrez et al ( 1987Gutierrez et al ( , 1988 and Zahner and Baumgiirtner (1988) a sine wave forced through daily temperature extremes approximates the temperature profile, and the daily increments in day-degrees are calculated by integrating the function above the lower developmental threshold T~j Gilbert et all, 1976). Physiological time in Equation (3), however, represents proportional development and is often used for wide temperature ranges (Logan et al, 1976 ).…”