Host stage preference and functional response of Aphidius matricariae (Hymenoptera: Braconidae) on tobacco aphid, Myzus nicotianae (Hemiptera: Aphididae)
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
The tobacco aphid, Myzus nicotianae Blackman (Hemiptera: Aphididae), is a serious pest of tobacco in many region of the world especially in Iran, causing direct damage to plants and indirect damage by transmitting important non-persistent viruses. Aphidius matricariae (Haliday) (Hymenoptera: Braconidae) is a solitary, polyphagous, koinobiont and endoparasitoid of more than 40 species of aphids. At present, many companies produce A. matricariae with different commercial names and spread around the world to use in biocontrol programs. Host stage preference and functional response are the most important behavioral characteristics to apply parasitoids in biocontrol programs. Therefore, the aim of this study was to investigate preference of A. matricariae to different life stage of M. nicotianae under choice and no-choice conditions. Also,functional response was determined by third instar nymphs of A. matricariae under different densities (2, 4, 8, 16, 32 and 64) of tobacco aphid in translucent plastic containers (11×10×4 cm) with ten replications. Tobacco plant, Nicotiana tabacum L. (Solanaceae), was used as host plant to establish aphid population. In both experiments, 1-day-old mated female parasitoid was exposed to the host aphids for 24h. The experiment was conducted in a constant environmental condition (25±1ºC; 70± 5% RH; 16:8 L:D h.) and honey solution (30 %) was used in cages as hydrocarbon source for the adult parasitoid wasps. The results indicated that there was significant difference between rates of parasitism on different life stages of M. nicotianae (P < 0.05). The number of hosts parasitized in both choice and no-choice preference tests were lowest in the first instar nymphs (0.20 and 0.70) and it was higher in the third (3.60 and 11.80) and fourth (2.90 and 9.90) instar nymphs. Also, using logistic regression, a type II functional response was determined for A. matricariae. After determination of the type of functional response, the Rogers model was used for estimating searching efficiency (a) and handling time (Th). The estimated values of searching efficiency and handling time were 0.0444±0.00815 h-1 and 0.5068±0.0872 h, respectively. Finally, the data obtained in this study will be useful in efficient utilization of A. matricariae for the biological control of tobacco aphid under natural field condition; nevertheless, further field-based researches are recommended.
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