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Density-Dependent Effects of Amphibian Prey on the Growth and Survival of an Endangered Giant Water Bug.

Ohba SY - Insects (2011)

Bottom Line: Higher tadpole density moderates predation pressure from the water scorpion Laccotrephes japonensis (Nepidae: Heteroptera) on K. deyrolli nymphs; i.e., it has a density-mediated indirect effect.These results suggest that an abundance of tadpoles in June provides food for K. deyrolli nymphs (a direct bottom-up effect) and moderates the predation pressure from L. japonensis (an indirect bottom-up effect).An abundance of amphibian prey is indispensable for the conservation of this endangered giant water bug species.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological Research, Kyoto University, 2-509-3 Hirano, Otsu 520-2113, Japan. oobug@hotmail.com.

ABSTRACT
Amphibian predator-insect prey relationships are common in terrestrial habitats, but amphibian larvae are preyed upon by a variety of aquatic hemipterans in aquatic habitats. This paper suggests that the survival of the nymphs of the endangered aquatic hemipteran Kirkaldyia (=Lethocerus) deyrolli (Belostomatidae: Heteroptera) is directly and indirectly affected by the abundance of their amphibian larval prey (tadpoles). Young nymphs of K. deyrolli mainly feed on tadpoles, regardless of differences in prey availability. Nymphs provided with tadpoles grow faster than nymphs provided with invertebrate prey. Therefore, tadpole consumption seems to be required to allow the nymphs to complete their larval development. In addition, the survival of K. deyrolli nymphs was greater during the period of highest tadpole density (June) than during a period of low tadpole density (July). Higher tadpole density moderates predation pressure from the water scorpion Laccotrephes japonensis (Nepidae: Heteroptera) on K. deyrolli nymphs; i.e., it has a density-mediated indirect effect. These results suggest that an abundance of tadpoles in June provides food for K. deyrolli nymphs (a direct bottom-up effect) and moderates the predation pressure from L. japonensis (an indirect bottom-up effect). An abundance of amphibian prey is indispensable for the conservation of this endangered giant water bug species.

No MeSH data available.


Prey groups included in the diets of K. deyrolli nymphs at three localities (modified from Ohba et al. [45]). The numbers indicate sample sizes.
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f3-insects-02-00435: Prey groups included in the diets of K. deyrolli nymphs at three localities (modified from Ohba et al. [45]). The numbers indicate sample sizes.

Mentions: In general, the appearance of younger nymphs of predacious insects when prey animals are abundant is expected to moderate cannibalism due to food shortages [41-44]. Accordingly, Ohba et al. [45] studied the ontogenetic diet shift of K. deyrolli by quantifying instar abundance and analyzing captured prey and prey relative abundance in rice fields in three localities. The first to third-instar K. deyrolli nymphs mainly fed on tadpoles, regardless of differences in prey availability among the three localities (Figure 3). A rearing experiment demonstrated that K. deyrolli nymphs provided with tadpoles displayed greater growth rates at all nymphal stages, except for the final stage, than nymphs fed on dragonflynymphs. The emergence of young K. deyrolli nymphs seemed to coincide with the period when tadpoles became abundant in the rice fields (Figure 4). In addition, the appearance of younger K. deyrolli nymphs when tadpoles are abundant is expected to moderate cannibalism due to food shortages, as has been demonstrated for other predatory insects such as ladybirds [41-44]. Actually, the frequency of cannibalism in K. deyrolli nymphs is lower than that seen in A. japonicus nymphs in the field (Figure 2) [7].


Density-Dependent Effects of Amphibian Prey on the Growth and Survival of an Endangered Giant Water Bug.

Ohba SY - Insects (2011)

Prey groups included in the diets of K. deyrolli nymphs at three localities (modified from Ohba et al. [45]). The numbers indicate sample sizes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553436&req=5

f3-insects-02-00435: Prey groups included in the diets of K. deyrolli nymphs at three localities (modified from Ohba et al. [45]). The numbers indicate sample sizes.
Mentions: In general, the appearance of younger nymphs of predacious insects when prey animals are abundant is expected to moderate cannibalism due to food shortages [41-44]. Accordingly, Ohba et al. [45] studied the ontogenetic diet shift of K. deyrolli by quantifying instar abundance and analyzing captured prey and prey relative abundance in rice fields in three localities. The first to third-instar K. deyrolli nymphs mainly fed on tadpoles, regardless of differences in prey availability among the three localities (Figure 3). A rearing experiment demonstrated that K. deyrolli nymphs provided with tadpoles displayed greater growth rates at all nymphal stages, except for the final stage, than nymphs fed on dragonflynymphs. The emergence of young K. deyrolli nymphs seemed to coincide with the period when tadpoles became abundant in the rice fields (Figure 4). In addition, the appearance of younger K. deyrolli nymphs when tadpoles are abundant is expected to moderate cannibalism due to food shortages, as has been demonstrated for other predatory insects such as ladybirds [41-44]. Actually, the frequency of cannibalism in K. deyrolli nymphs is lower than that seen in A. japonicus nymphs in the field (Figure 2) [7].

Bottom Line: Higher tadpole density moderates predation pressure from the water scorpion Laccotrephes japonensis (Nepidae: Heteroptera) on K. deyrolli nymphs; i.e., it has a density-mediated indirect effect.These results suggest that an abundance of tadpoles in June provides food for K. deyrolli nymphs (a direct bottom-up effect) and moderates the predation pressure from L. japonensis (an indirect bottom-up effect).An abundance of amphibian prey is indispensable for the conservation of this endangered giant water bug species.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological Research, Kyoto University, 2-509-3 Hirano, Otsu 520-2113, Japan. oobug@hotmail.com.

ABSTRACT
Amphibian predator-insect prey relationships are common in terrestrial habitats, but amphibian larvae are preyed upon by a variety of aquatic hemipterans in aquatic habitats. This paper suggests that the survival of the nymphs of the endangered aquatic hemipteran Kirkaldyia (=Lethocerus) deyrolli (Belostomatidae: Heteroptera) is directly and indirectly affected by the abundance of their amphibian larval prey (tadpoles). Young nymphs of K. deyrolli mainly feed on tadpoles, regardless of differences in prey availability. Nymphs provided with tadpoles grow faster than nymphs provided with invertebrate prey. Therefore, tadpole consumption seems to be required to allow the nymphs to complete their larval development. In addition, the survival of K. deyrolli nymphs was greater during the period of highest tadpole density (June) than during a period of low tadpole density (July). Higher tadpole density moderates predation pressure from the water scorpion Laccotrephes japonensis (Nepidae: Heteroptera) on K. deyrolli nymphs; i.e., it has a density-mediated indirect effect. These results suggest that an abundance of tadpoles in June provides food for K. deyrolli nymphs (a direct bottom-up effect) and moderates the predation pressure from L. japonensis (an indirect bottom-up effect). An abundance of amphibian prey is indispensable for the conservation of this endangered giant water bug species.

No MeSH data available.