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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.


Predation on a tadpole by an aquatic insect. As one example of the recorded dietary items, prey into which a predator’s proboscis had been inserted is shown in this photo.
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f1-insects-02-00435: Predation on a tadpole by an aquatic insect. As one example of the recorded dietary items, prey into which a predator’s proboscis had been inserted is shown in this photo.

Mentions: However, most aquatic hemipterans do not often eat tadpoles in Japan. Ohba and Nakasuji [7] investigated the feeding habits of aquatic bugs (Nepoidea, including Belostomatidae and Nepidae) by performing direct observations in wetland areas (see Figure 1) and obtaining data from the published literature [29-31]. As a result, it was found that sympatric species (Appasus japonicus, Kirkaldyia deyrolli, and Laccotrephes japonensis) displayed differences in their dietary components (Figure 2). Although tadpoles are preyed upon by a variety of aquatic insects, not all aquatic insect species eat tadpoles. Only K. deyrolli nymphs and L. japonensis adults greatly depend on tadpoles whereas A. japonicus does not eat tadpoles. Therefore, K. deyrolli nymphs and L. japonensis adults seem to be members of the same guild; i.e., they compete with each other, in Japanese wetlands [32].


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

Ohba SY - Insects (2011)

Predation on a tadpole by an aquatic insect. As one example of the recorded dietary items, prey into which a predator’s proboscis had been inserted is shown in this photo.
© Copyright Policy
Related In: Results  -  Collection

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

f1-insects-02-00435: Predation on a tadpole by an aquatic insect. As one example of the recorded dietary items, prey into which a predator’s proboscis had been inserted is shown in this photo.
Mentions: However, most aquatic hemipterans do not often eat tadpoles in Japan. Ohba and Nakasuji [7] investigated the feeding habits of aquatic bugs (Nepoidea, including Belostomatidae and Nepidae) by performing direct observations in wetland areas (see Figure 1) and obtaining data from the published literature [29-31]. As a result, it was found that sympatric species (Appasus japonicus, Kirkaldyia deyrolli, and Laccotrephes japonensis) displayed differences in their dietary components (Figure 2). Although tadpoles are preyed upon by a variety of aquatic insects, not all aquatic insect species eat tadpoles. Only K. deyrolli nymphs and L. japonensis adults greatly depend on tadpoles whereas A. japonicus does not eat tadpoles. Therefore, K. deyrolli nymphs and L. japonensis adults seem to be members of the same guild; i.e., they compete with each other, in Japanese wetlands [32].

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.