Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz (1998) 71, 53-56

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B. Liu and Ç. Sengonca (1998)
Functional responses of the parasitoid, Eretmocerus longipes Compere (Hym., Aphelinidae) to densities of the whitefly, Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae) at different temperatures
Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz 71 (3), 53-56
Abstract: The present study dealt with the functional responses of the parasitoid, Eretmocerus longipes Compere (Hym., Aphelinidae) to the densities of the whitefly, Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae) at different temperatures under the laboratory conditions. The results showed that when the initial densities of A. takahashi-3rd instar were raised from 10 to 320 ind./leaf, the numbers of parasitized nymphs increased as well, ranging from 7.0 to 23.1 at 20 °C, 9.8 to 42.9 at 25 °C, 6.7 to 39.9 at 30 °C, and 1.8 to 8.3 ind./leaf at 35 °C, respectively. The Holling Disk Equation was introduced to build up the models of functional responses. The response curves remained type II, although the numbers of parasitized nymphs were significantly different under different temperatures. The suitable initial densities of the host whitefly for parasitization were about 80 individuals per leaf. A negative relation was observed between the initial densities of the whitefly and the parasitization rates by the parasitoid. An increase in the initial densities of A. takahashi-3rd instars ranging from 10 to 320 ind./leaf resulted in a decrease in the parasitization rate by E. longipes ranging from 70.0% to 7.2% at 20°C, 98.0% to 13.4% at 25°C, 67.0% to 12.5% at 30°C and 18.0% to 2.6% at 35°C, respectively. The searching rate (a) of E. longipes at 35°C with a value of 0.2877 was significantly smaller than that at 20°C with a value of 1.3354, that at 25 °C with a value of 1.6465 and that at 30 °C with a value of 1.1199, respectively (p<0.01). The handling time (Th) for E. longipes was 0.1521 at 35°C, significantly longer than 0.0510 at 20°C, 0.0289 at 25°C and 0.0320 at 30°C, respectively (p<0.01). The maximum loading number (K) of the parasitized nymphs with a value of 34.5 ind./leaf at 25°C was similar to that with a value of 31.2 ind./leaf at 30°C, about 1.8 times as high as that with a value of 19.6 ind./leaf at 20 °C and 4 times more than that with a value of 6.6 ind./leaf at 35 °C. It was suggested that temperature affected the functional response by balancing searching rate and handling time. The optimal temperature range for the functional responses of E. longipes to the densities of A. takahashi-3rd instar was 25° to 30°C.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Cetin Sengonca

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
identification/taxonomy


Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.


Aleurotuberculatus takahashi
Eretmocerus longipes (parasitoid) Aleurotuberculatus takahashi