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Competitive interactions between parasitoids provide new insight into host suppression.

Xu HY, Yang NW, Wan FH - PLoS ONE (2013)

Bottom Line: Understanding the dynamics of potential inter- and intraspecific competition in parasitoid communities is crucial in the screening of efficient parasitoid species and for utilization of the best parasitoid species combinations.Results showed that (1) both parasitoid species negatively affect the progeny production of the other under both rich and limited host resource conditions; (2) both parasitoid species interfered intraspecifically on conspecific parasitized hosts when the available hosts are scarce and; 3) the mortality of B. tabaci induced by parasitoids via parasitism, host-feeding or both parasitism and host-feeding together varied among treatments under different host resource conditions, but showed promise for optimizing control strategies.As a result of our current findings, we suggest a need to investigate the interactions between the two parasitoids on continuous generations.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, P. R. China.

ABSTRACT
Understanding the dynamics of potential inter- and intraspecific competition in parasitoid communities is crucial in the screening of efficient parasitoid species and for utilization of the best parasitoid species combinations. In this respect, the host-parasitoid systems, Bemisia tabaci and two parasitoids, Eretmocerus hayati (exotic) and Encarsia sophia (existing) were studied under laboratory conditions to investigate whether interference competition between the exotic and existing species occurs as well as the influence of potential interference competition on the suppression of the host B. tabaci. Studies on interspecific-, intraspecific- and self-interference competition in two parasitoid species were conducted under both rich and limited host resource conditions. Results showed that (1) both parasitoid species negatively affect the progeny production of the other under both rich and limited host resource conditions; (2) both parasitoid species interfered intraspecifically on conspecific parasitized hosts when the available hosts are scarce and; 3) the mortality of B. tabaci induced by parasitoids via parasitism, host-feeding or both parasitism and host-feeding together varied among treatments under different host resource conditions, but showed promise for optimizing control strategies. As a result of our current findings, we suggest a need to investigate the interactions between the two parasitoids on continuous generations.

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Mean number of whitefly killed by parasitoids via parasitism, host-feeding, and both parasitism and host-feeding when Eretmocerushayati was introduced into the leaf cage first.A: under the rich host resource condition; B: under the limited host resource condition. An area of 3.5 cm2 of a leaf on a potted tomato plant was covered by a clip cage. H, H/S, H1/H2 and H1/H1 represented the four treatments: Er. hayati was introduced into the leaf cage alone for 24 h (with no subsequent parasitoid female introduced), followed by a heterospecific female (En. sophia) for another 24 h, followed by a conspecific female (Er. hayati) for another 24 h and followed by itself for another 24h, respectively. Sample sizes of treatments H, H/S, H1/H2 and H1/H1 are 40, 22, 22, 30 and 40, 20, 20, 20 under the rich and limited host resource condition, respectively. Bar heads with different lowercase letters in each cluster indicate significant differences in number of hosts killed among different treatments (multiple comparison procedure based on the Tukey test after the Kruskal-Wallis test, P < 0.05); no significant difference was found in parasitism under the rich host resource condition (Kruskal-Wallis test, χ2 = 6.92, df = 3, P = 0.074).
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pone-0082003-g003: Mean number of whitefly killed by parasitoids via parasitism, host-feeding, and both parasitism and host-feeding when Eretmocerushayati was introduced into the leaf cage first.A: under the rich host resource condition; B: under the limited host resource condition. An area of 3.5 cm2 of a leaf on a potted tomato plant was covered by a clip cage. H, H/S, H1/H2 and H1/H1 represented the four treatments: Er. hayati was introduced into the leaf cage alone for 24 h (with no subsequent parasitoid female introduced), followed by a heterospecific female (En. sophia) for another 24 h, followed by a conspecific female (Er. hayati) for another 24 h and followed by itself for another 24h, respectively. Sample sizes of treatments H, H/S, H1/H2 and H1/H1 are 40, 22, 22, 30 and 40, 20, 20, 20 under the rich and limited host resource condition, respectively. Bar heads with different lowercase letters in each cluster indicate significant differences in number of hosts killed among different treatments (multiple comparison procedure based on the Tukey test after the Kruskal-Wallis test, P < 0.05); no significant difference was found in parasitism under the rich host resource condition (Kruskal-Wallis test, χ2 = 6.92, df = 3, P = 0.074).

Mentions: Regardless of the rich or limited host resource conditions, the subsequent introduction of the heterospcific parasitoid En. sophia (H/S treatment) caused the lowest number of total progeny among treatments, although it was not significantly different under the rich host resource condition (Figure 3A; χ2 = 6.92, df = 3, P =0.074) but significantly different under the limited host resource condition (Figure 3B; χ2 = 28.46, df = 3, P < 0.0001).


Competitive interactions between parasitoids provide new insight into host suppression.

Xu HY, Yang NW, Wan FH - PLoS ONE (2013)

Mean number of whitefly killed by parasitoids via parasitism, host-feeding, and both parasitism and host-feeding when Eretmocerushayati was introduced into the leaf cage first.A: under the rich host resource condition; B: under the limited host resource condition. An area of 3.5 cm2 of a leaf on a potted tomato plant was covered by a clip cage. H, H/S, H1/H2 and H1/H1 represented the four treatments: Er. hayati was introduced into the leaf cage alone for 24 h (with no subsequent parasitoid female introduced), followed by a heterospecific female (En. sophia) for another 24 h, followed by a conspecific female (Er. hayati) for another 24 h and followed by itself for another 24h, respectively. Sample sizes of treatments H, H/S, H1/H2 and H1/H1 are 40, 22, 22, 30 and 40, 20, 20, 20 under the rich and limited host resource condition, respectively. Bar heads with different lowercase letters in each cluster indicate significant differences in number of hosts killed among different treatments (multiple comparison procedure based on the Tukey test after the Kruskal-Wallis test, P < 0.05); no significant difference was found in parasitism under the rich host resource condition (Kruskal-Wallis test, χ2 = 6.92, df = 3, P = 0.074).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3842984&req=5

pone-0082003-g003: Mean number of whitefly killed by parasitoids via parasitism, host-feeding, and both parasitism and host-feeding when Eretmocerushayati was introduced into the leaf cage first.A: under the rich host resource condition; B: under the limited host resource condition. An area of 3.5 cm2 of a leaf on a potted tomato plant was covered by a clip cage. H, H/S, H1/H2 and H1/H1 represented the four treatments: Er. hayati was introduced into the leaf cage alone for 24 h (with no subsequent parasitoid female introduced), followed by a heterospecific female (En. sophia) for another 24 h, followed by a conspecific female (Er. hayati) for another 24 h and followed by itself for another 24h, respectively. Sample sizes of treatments H, H/S, H1/H2 and H1/H1 are 40, 22, 22, 30 and 40, 20, 20, 20 under the rich and limited host resource condition, respectively. Bar heads with different lowercase letters in each cluster indicate significant differences in number of hosts killed among different treatments (multiple comparison procedure based on the Tukey test after the Kruskal-Wallis test, P < 0.05); no significant difference was found in parasitism under the rich host resource condition (Kruskal-Wallis test, χ2 = 6.92, df = 3, P = 0.074).
Mentions: Regardless of the rich or limited host resource conditions, the subsequent introduction of the heterospcific parasitoid En. sophia (H/S treatment) caused the lowest number of total progeny among treatments, although it was not significantly different under the rich host resource condition (Figure 3A; χ2 = 6.92, df = 3, P =0.074) but significantly different under the limited host resource condition (Figure 3B; χ2 = 28.46, df = 3, P < 0.0001).

Bottom Line: Understanding the dynamics of potential inter- and intraspecific competition in parasitoid communities is crucial in the screening of efficient parasitoid species and for utilization of the best parasitoid species combinations.Results showed that (1) both parasitoid species negatively affect the progeny production of the other under both rich and limited host resource conditions; (2) both parasitoid species interfered intraspecifically on conspecific parasitized hosts when the available hosts are scarce and; 3) the mortality of B. tabaci induced by parasitoids via parasitism, host-feeding or both parasitism and host-feeding together varied among treatments under different host resource conditions, but showed promise for optimizing control strategies.As a result of our current findings, we suggest a need to investigate the interactions between the two parasitoids on continuous generations.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, P. R. China.

ABSTRACT
Understanding the dynamics of potential inter- and intraspecific competition in parasitoid communities is crucial in the screening of efficient parasitoid species and for utilization of the best parasitoid species combinations. In this respect, the host-parasitoid systems, Bemisia tabaci and two parasitoids, Eretmocerus hayati (exotic) and Encarsia sophia (existing) were studied under laboratory conditions to investigate whether interference competition between the exotic and existing species occurs as well as the influence of potential interference competition on the suppression of the host B. tabaci. Studies on interspecific-, intraspecific- and self-interference competition in two parasitoid species were conducted under both rich and limited host resource conditions. Results showed that (1) both parasitoid species negatively affect the progeny production of the other under both rich and limited host resource conditions; (2) both parasitoid species interfered intraspecifically on conspecific parasitized hosts when the available hosts are scarce and; 3) the mortality of B. tabaci induced by parasitoids via parasitism, host-feeding or both parasitism and host-feeding together varied among treatments under different host resource conditions, but showed promise for optimizing control strategies. As a result of our current findings, we suggest a need to investigate the interactions between the two parasitoids on continuous generations.

Show MeSH
Related in: MedlinePlus