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Prey preference and host suitability of the predatory and parasitoid carabid beetle, Lebia grandis, for several species of Leptinotarsa beetles.

Weber DC, Rowley DL, Greenstone MH, Athanas MM - J. Insect Sci. (2006)

Bottom Line: Our laboratory comparisons suggest that L. juncta, the presumptive original host, best supports the development of the parasitoid larval L. grandis, based on 43.6% successful emergence of the adult carabid parasitoid, compared to 11.5% from the two other Leptinotarsa species.Naive, newly-emerged adults show no preference when presented the 3 species of third-instar larvae, which they consume at a mean rate of 3.3 per day, a rate which does not differ significantly by sex, larval host, or weight at emergence.When presented with equal amounts by weight of the 3 species of Leptinotarsa eggs, such adults consume the equivalent of 23.0 L. decemlineata eggs per day, with consumption of L. juncta eggs 67% higher by weight than L. decemlineata consumption.

View Article: PubMed Central - PubMed

Affiliation: Insect Biocontrol Laboratory, USDA ARS PSI, BARC-West, Beltsville, MD 20705, USA. weberd@ba.ars.usda.gov

ABSTRACT
Lebia grandis (Coleoptera: Carabidae), recorded as a parasitoid only on Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), is capable of parasitizing the false potato beetle, L. juncta, and also L. haldemani. Historical records show that L. decemlineata, while the only recorded host, was not present in much of the original range of L. grandis, and may not have been its host prior to its expansion into eastern North America, where L. juncta is endemic. Our laboratory comparisons suggest that L. juncta, the presumptive original host, best supports the development of the parasitoid larval L. grandis, based on 43.6% successful emergence of the adult carabid parasitoid, compared to 11.5% from the two other Leptinotarsa species. L. grandis adults accept eggs and larvae of all 3 Leptinotarsa species as adult food. Naive, newly-emerged adults show no preference when presented the 3 species of third-instar larvae, which they consume at a mean rate of 3.3 per day, a rate which does not differ significantly by sex, larval host, or weight at emergence. When presented with equal amounts by weight of the 3 species of Leptinotarsa eggs, such adults consume the equivalent of 23.0 L. decemlineata eggs per day, with consumption of L. juncta eggs 67% higher by weight than L. decemlineata consumption. Insight into the biotic and abiotic limitations on L. grandis should aid in determining its potential for suppression of Colorado potato beetle by biological control in diverse agroecosystems.

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Egg-choice arena showing 3 species of egg masses (each equivalent to 31.4 mg): 21 eggs of Leptinotarsa juncta (pink to salmon in color); 37 eggs of Leptinotarsa haldemani (beige to brown); 50 eggs of Leptinotarsa decemlineata (yellow-orange). These were placed with randomized orientation between moistened cotton wicks and shelter of shredded wax paper in 300 ml container. Note adult Lebia grandis in wax paper.
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i1536-2442-6-9-1-f07: Egg-choice arena showing 3 species of egg masses (each equivalent to 31.4 mg): 21 eggs of Leptinotarsa juncta (pink to salmon in color); 37 eggs of Leptinotarsa haldemani (beige to brown); 50 eggs of Leptinotarsa decemlineata (yellow-orange). These were placed with randomized orientation between moistened cotton wicks and shelter of shredded wax paper in 300 ml container. Note adult Lebia grandis in wax paper.

Mentions: Twelve newly-emerged L. grandis adults (12 F1 offspring of adults collected in July 2004 from a potato field in Beltsville, Maryland) were weighed within one day of emergence and then housed singly in 300 ml containers as above, and offered 50 eggs of L. decemlineata, 37 eggs of L. haldemani, and 21 eggs of L. juncta, each having an approximate total mass of 31.4 mg. The three egg groups were symmetrically spaced around the margin of a 35 mm open Petri dish top, which was placed in the middle of the container bottom, between the shredded wax paper and the moistened dental wicks, with random egg species orientation (Figure 7). Each day for 5 to 6 days, the eggs were counted and replenished to the original numbers, and any hatching or near-to-hatching eggs also replaced. Following the choice experiment, adult L. grandis were sexed. The hypothesis, that the adults consumed equal mass of eggs of each species, was tested using Proc Mixed (SAS Institute 2005) to conduct a 2-way ANOVA with one factor indicating whether the distribution is “observed” or “expected” (i.e. equivalent proportion, set to one-third for each species) and the other factor representing the 3 species. Each adult was a replicate experimental unit; the dependent variable was the by-mass proportion of total mass of eggs consumed. Significance of the 2-way interaction effect would indicate non-equivalent preference. The relationship between egg consumption and day was examined as above for larvae.


Prey preference and host suitability of the predatory and parasitoid carabid beetle, Lebia grandis, for several species of Leptinotarsa beetles.

Weber DC, Rowley DL, Greenstone MH, Athanas MM - J. Insect Sci. (2006)

Egg-choice arena showing 3 species of egg masses (each equivalent to 31.4 mg): 21 eggs of Leptinotarsa juncta (pink to salmon in color); 37 eggs of Leptinotarsa haldemani (beige to brown); 50 eggs of Leptinotarsa decemlineata (yellow-orange). These were placed with randomized orientation between moistened cotton wicks and shelter of shredded wax paper in 300 ml container. Note adult Lebia grandis in wax paper.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2990295&req=5

i1536-2442-6-9-1-f07: Egg-choice arena showing 3 species of egg masses (each equivalent to 31.4 mg): 21 eggs of Leptinotarsa juncta (pink to salmon in color); 37 eggs of Leptinotarsa haldemani (beige to brown); 50 eggs of Leptinotarsa decemlineata (yellow-orange). These were placed with randomized orientation between moistened cotton wicks and shelter of shredded wax paper in 300 ml container. Note adult Lebia grandis in wax paper.
Mentions: Twelve newly-emerged L. grandis adults (12 F1 offspring of adults collected in July 2004 from a potato field in Beltsville, Maryland) were weighed within one day of emergence and then housed singly in 300 ml containers as above, and offered 50 eggs of L. decemlineata, 37 eggs of L. haldemani, and 21 eggs of L. juncta, each having an approximate total mass of 31.4 mg. The three egg groups were symmetrically spaced around the margin of a 35 mm open Petri dish top, which was placed in the middle of the container bottom, between the shredded wax paper and the moistened dental wicks, with random egg species orientation (Figure 7). Each day for 5 to 6 days, the eggs were counted and replenished to the original numbers, and any hatching or near-to-hatching eggs also replaced. Following the choice experiment, adult L. grandis were sexed. The hypothesis, that the adults consumed equal mass of eggs of each species, was tested using Proc Mixed (SAS Institute 2005) to conduct a 2-way ANOVA with one factor indicating whether the distribution is “observed” or “expected” (i.e. equivalent proportion, set to one-third for each species) and the other factor representing the 3 species. Each adult was a replicate experimental unit; the dependent variable was the by-mass proportion of total mass of eggs consumed. Significance of the 2-way interaction effect would indicate non-equivalent preference. The relationship between egg consumption and day was examined as above for larvae.

Bottom Line: Our laboratory comparisons suggest that L. juncta, the presumptive original host, best supports the development of the parasitoid larval L. grandis, based on 43.6% successful emergence of the adult carabid parasitoid, compared to 11.5% from the two other Leptinotarsa species.Naive, newly-emerged adults show no preference when presented the 3 species of third-instar larvae, which they consume at a mean rate of 3.3 per day, a rate which does not differ significantly by sex, larval host, or weight at emergence.When presented with equal amounts by weight of the 3 species of Leptinotarsa eggs, such adults consume the equivalent of 23.0 L. decemlineata eggs per day, with consumption of L. juncta eggs 67% higher by weight than L. decemlineata consumption.

View Article: PubMed Central - PubMed

Affiliation: Insect Biocontrol Laboratory, USDA ARS PSI, BARC-West, Beltsville, MD 20705, USA. weberd@ba.ars.usda.gov

ABSTRACT
Lebia grandis (Coleoptera: Carabidae), recorded as a parasitoid only on Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), is capable of parasitizing the false potato beetle, L. juncta, and also L. haldemani. Historical records show that L. decemlineata, while the only recorded host, was not present in much of the original range of L. grandis, and may not have been its host prior to its expansion into eastern North America, where L. juncta is endemic. Our laboratory comparisons suggest that L. juncta, the presumptive original host, best supports the development of the parasitoid larval L. grandis, based on 43.6% successful emergence of the adult carabid parasitoid, compared to 11.5% from the two other Leptinotarsa species. L. grandis adults accept eggs and larvae of all 3 Leptinotarsa species as adult food. Naive, newly-emerged adults show no preference when presented the 3 species of third-instar larvae, which they consume at a mean rate of 3.3 per day, a rate which does not differ significantly by sex, larval host, or weight at emergence. When presented with equal amounts by weight of the 3 species of Leptinotarsa eggs, such adults consume the equivalent of 23.0 L. decemlineata eggs per day, with consumption of L. juncta eggs 67% higher by weight than L. decemlineata consumption. Insight into the biotic and abiotic limitations on L. grandis should aid in determining its potential for suppression of Colorado potato beetle by biological control in diverse agroecosystems.

Show MeSH
Related in: MedlinePlus