Functional response and host preference of<i>Encarsia formosa</i>: Gahan (Hym., Aphelinidae), a parasitoid of greenhouse whitefly<i>T. vaporariorum</i>(Westwood) (Hom., Aleyrodidae)

Fransen, J. J.; Montfort, M.A.J. van

doi:10.1111/j.1439-0418.1987.tb00960.x

Cited by 28 publications

(22 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The handling time compares well with the one found at 28 ~ in this study (Th = 1.54 h, i.e. Fransen and Montfort (1987) determined the functional response of E. formosa parasitizing different larval stages of T. vaporariorum in a laboratory experiment on beans at 25 ~ L16:D8. The search rate of 0.104 plant.day -t found by Yano (1987) could not be compared to the present result since leaf area and number of leaves per plant was not specified.…”

Section: Discussionsupporting

confidence: 81%

“…Since the functional response of E. formosa varies with the instar of the whitefly (Fransen & Montfort, 1987;Yano, 1987), only hosts of the same age group were presented to the parasitoids. To allow maximum expression of the parasitoid response potential, one of the most preferred instars -the fourth (Enkegaard, 1993b) -was chosen for the experiments.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Temperature dependent functional response of Encarsia formosa parasitizing the Poinsettia‐strain of the cotton whitefly, Bemisia tabaci, on Poinsettia

Enkegaard¹

1994

Entomologia Exp Applicata

View full text Add to dashboard Cite

The control efficiency and performance of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) as influenced by the density of its host, the Poinsettia-strain of Bemisia tabaci Gennadius (Homoptera: Aleyrodidae), were investigated by laboratory experiments on Poinsettia (Euphorbia pulcherrrima Willd.). E. formosa showed a Type II functional response to fourth instar larvae of B. tabaci, the response plateau increasing with temperature. A response model for randomly searching parasitoids incorporating temperature-dependent handling time and temperature-independent search rate was in accordance with the results, and gave an estimated search rate of 0.033 leaf.hour -~ and handling times of 1.54, 2.86 and 20.1 h at 28 ~ 22 ~ and 16 ~ respectively. From the latter, the maximum number of hosts that can be parasitized at the three temperatures are 10.4, 5.6 and 0.8 larvae per day (provided the light period is 16 h). The number of hosts with ovipositor punctures was higher than the number of parasitized hosts, especially at 22 ~ and 28~ implying that E. formosa refrains from laying eggs in some of the hosts examined with the ovipositor. About 31% of the punctured larvae did not contain any eggs. Superparasitism occured during the experiment presumably originating from young, inexperienced parasitoids. Individual larvae were occasionally punctured several times, also by non-superparasitizing E. formosa. The resulting distribution of ovipositior holes was random, indicating that E. formosa on the basis of antennal testing is unable to determine if a larva has previously been examined with the ovipositor. Almost fifty percent of the punctures were not followed by egg-depositions. Besides parasitization E. formosa used hosts as food source. The number of hostfed larvae was independent of density, but varied with temperature being highest at 28 ~ (0.12 hostfed larvae per parasitoid per day).

show abstract

Section: Discussionsupporting

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Temperature dependent functional response of Encarsia formosa parasitizing the Poinsettia‐strain of the cotton whitefly, Bemisia tabaci, on Poinsettia

Enkegaard¹

1994

Entomologia Exp Applicata

View full text Add to dashboard Cite

show abstract

“…The rest of the encountered hosts is rejected because of egg limitation. This corresponds reasonably well to empirical studies on E. formosa not used for parameterisation, although the predicted daily number of host feedings is somewhat high (van Alphen et al 1976, Arakawa 1982, Fransen and van Montfort 1987, Sütterlin and van Lenteren 1999). Lower temperatures or longer host feeding times could account for lower host‐feeding ratios (Table 3).…”

Section: Discussionsupporting

confidence: 85%

Reproduction now or later: optimal host‐handling strategies in the whitefly parasitoidEncarsia formosa

Burger¹,

Hemerik²,

Lenteren³

et al. 2004

Oikos

View full text Add to dashboard Cite

We developed a dynamic state variable model for studying optimal host-handling strategies in the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). We assumed that (a) the function of host feeding is to gain nutrients that can be matured into eggs, (b) oögenesis is continuous and egg load dependent, (c) parasitoid survival is exponentially distributed and (d) parasitoids encounter hosts randomly, are autogenous and have unlimited access to non-host food sources to obtain energy for maintenance and activity. The most important prediction of the model is that host feeding is maladaptive under field conditions of low host density (0.015 cm (2 ) and short parasitoid life expectancy (maximum reproductive period of 7 days). Nutrients from the immature stage that can be matured into eggs are sufficient to prevent egg limitation. Both host density and parasitoid life expectancy have a positive effect on the optimal host-feeding ratio. Parasitoids that make random decisions gain on average only 35% (0.015 hosts cm (2 ) to 60% (1.5 hosts cm (2 ) of the lifetime reproductive success of parasitoids that make optimal decisions, independent of their life expectancy. Parameters that have a large impact on lifetime reproductive success and therefore drive natural selection are parasitoid life expectancy and the survival probability of deposited eggs (independent of host density), the number of host encounters per day (when host density is low) and the egg maturation rate and number of host types (when host density is high). Explaining the evolution of host-feeding behaviour under field conditions requires field data showing that life expectancy in the field is not as short as we assumed, or may require incorporation of variation in host density. Incorporating variation in walking speed, parasitised host types or egg resorption is not expected to provide an explanation for the evolution of host-feeding behaviour under field conditions. Natural selection favours organisms that behave in a way that maximises their lifetime reproductive output. Insect parasitoids are good model systems to study evolution of behaviour because of the direct link between behaviour and reproductive output (Stephens and Krebs 1986, Godfray 1994). Host feeding behaviour is the consumption of host body fluids by the adult female parasitoid (Flanders 1942). It provides nutrients that allow parasitoids to mature eggs or to increase longevity (Jervis and

show abstract

“…Unfortunately, a number of other functional response studies on similar parasitoids do not provide sufficient data to be able to determine the pattern of increase at lower host densities, and by default have characterised the response as type II (e.g. Kfir, 1983; Fransen & Montfort, 1987; Greenberg et al ., 2001).…”

Section: Discussionmentioning

confidence: 99%

Ratio dependence in the functional response of insect parasitoids: evidence fromTrichogramma minutumforaging for eggs in small host patches

Mills

Laćan

2004

Ecological Entomology

View full text Add to dashboard Cite

Abstract. 1. Despite considerable recent debate on the suitability of ratio dependence as a more general form for the functional response in consumer–victim relationships, there have been few detailed studies to experimentally determine the response of insect parasitoids to host and parasitoid density at a local scale. 2. The experimental host, Ephestia kuehniella, was used to test for host dependence and ratio dependence in the functional response of the egg parasitoid, Trichogramma minutum, a species widely used in inundative biological control. The functional response was examined through four series of experiments in which either host density, parasitoid density, or the ratio of previously parasitised to healthy hosts was manipulated. 3. The response to host density was type I for both single and simultaneously foraging parasitoids, indicating a lack of host dependence in the functional response. The upper limit to the response was estimated as 39 hosts attacked in a 24‐h period, with an estimated per capita search rate of 1.32 for individual females and 0.37 for three simultaneously searching females. 4. The response to parasitoid density provided an interference constant of unity, indicating an equal sharing of hosts and thus ratio dependence in the functional response. Female parasitoids responded to the presence of conspecifically parasitised eggs with a significant increase in search rate (1.75), but with no change to the form or upper limit of the response. 5. It is suggested that ratio dependence may be more common among insect parasitoids than previously supposed, and that a type I functional response, or the absence of host dependence, may be an emergent property of phylogenetic constraint within the monophyletic grouping of Cales, Eretmocerus, and Trichogramma.

show abstract

Functional response and host preference ofEncarsia formosa: Gahan (Hym., Aphelinidae), a parasitoid of greenhouse whiteflyT. vaporariorum(Westwood) (Hom., Aleyrodidae)

Cited by 28 publications

References 16 publications

Temperature dependent functional response of Encarsia formosa parasitizing the Poinsettia‐strain of the cotton whitefly, Bemisia tabaci, on Poinsettia

Temperature dependent functional response of Encarsia formosa parasitizing the Poinsettia‐strain of the cotton whitefly, Bemisia tabaci, on Poinsettia

Reproduction now or later: optimal host‐handling strategies in the whitefly parasitoidEncarsia formosa

Ratio dependence in the functional response of insect parasitoids: evidence fromTrichogramma minutumforaging for eggs in small host patches

Contact Info

Product

Resources

About