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Experimental evaluation of herbivory on live plant seedlings by the earthworm Lumbricus terrestris L. in the presence and absence of soil surface litter.

Kirchberger J, Eisenhauer N, Weisser WW, Türke M - PLoS ONE (2015)

Bottom Line: Lumbricus terrestris preferred to consume legume litter over litter of the other plant functional groups.Pulling live plants into earthworm burrows might induce microbial decomposition of leaves to make them suitable for later consumption.Herbivory on plants beyond the initial seedling stage may only play a minor role in earthworm nutrition and has limited potential to influence plant growth.

View Article: PubMed Central - PubMed

Affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany.

ABSTRACT

Background: Recent studies suggested that the earthworm Lumbricus terrestris might act as a seedling predator by ingesting emerging seedlings, and individuals were observed damaging fresh leaves of various plant species in the field. To evaluate the significance of herbivore behavior of L. terrestris for plant and earthworm performance we exposed 23- to 33-days-old seedlings of six plant species to earthworms in two microcosm experiments. Plants belonged to the three functional groups grasses, non-leguminous herbs, and legumes. Leaf damage, leaf mortality, the number of leaves as well as mortality and growth of seedlings were followed over a period of up to 26 days. In a subset of replicates 0.1 g of soil surface litter of each of the six plant species was provided and consumption was estimated regularly to determine potential feeding preferences of earthworms.

Results: There was no difference in seedling growth, the number of live seedlings and dead leaves between treatments with or without worms. Fresh leaves were damaged eight times during the experiment, most likely by L. terrestris, with two direct observations of earthworms tearing off leaf parts. Another nine leaves were partly pulled into earthworm burrows. Lumbricus terrestris preferred to consume legume litter over litter of the other plant functional groups. Earthworms that consumed litter lost less weight than individuals that were provided with soil and live plants only, indicating that live plants are not a suitable substitute for litter in earthworm nutrition.

Conclusion: Our results demonstrate that L. terrestris damages live plants; however, this behavior occurs only rarely. Pulling live plants into earthworm burrows might induce microbial decomposition of leaves to make them suitable for later consumption. Herbivory on plants beyond the initial seedling stage may only play a minor role in earthworm nutrition and has limited potential to influence plant growth.

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Decrease of soil surface litter consumed by earthworms.(A) Decrease of soil surface litter of different plant species in microcosms with L. terrestris (N = 12, results are given as mean ± SE) and (B) remaining litter of different plant functional groups after 23 days (results are given as mean ± 95%-confidence intervals).
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pone.0123465.g005: Decrease of soil surface litter consumed by earthworms.(A) Decrease of soil surface litter of different plant species in microcosms with L. terrestris (N = 12, results are given as mean ± SE) and (B) remaining litter of different plant functional groups after 23 days (results are given as mean ± 95%-confidence intervals).

Mentions: Results of an ANOVA comparing litter persistence time among treatments are shown in Table 3. Litter material was not removed from the soil surface in the absence of earthworms (n = 5). By contrast, the amount of soil surface litter decreased over the course of the experiment in the presence of L. terrestris (n = 12, two of the 14 individuals did not feed on litter; Fig 5). On average, roughly half of the litter material (52%) was consumed after 15 days, and only 15% of the litter material remained after 23 days (end of the experiment). The persistence time of litter differed significantly between microcosms with and without L. terrestris (Table 3; S1 Statistics, S1.7).


Experimental evaluation of herbivory on live plant seedlings by the earthworm Lumbricus terrestris L. in the presence and absence of soil surface litter.

Kirchberger J, Eisenhauer N, Weisser WW, Türke M - PLoS ONE (2015)

Decrease of soil surface litter consumed by earthworms.(A) Decrease of soil surface litter of different plant species in microcosms with L. terrestris (N = 12, results are given as mean ± SE) and (B) remaining litter of different plant functional groups after 23 days (results are given as mean ± 95%-confidence intervals).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401770&req=5

pone.0123465.g005: Decrease of soil surface litter consumed by earthworms.(A) Decrease of soil surface litter of different plant species in microcosms with L. terrestris (N = 12, results are given as mean ± SE) and (B) remaining litter of different plant functional groups after 23 days (results are given as mean ± 95%-confidence intervals).
Mentions: Results of an ANOVA comparing litter persistence time among treatments are shown in Table 3. Litter material was not removed from the soil surface in the absence of earthworms (n = 5). By contrast, the amount of soil surface litter decreased over the course of the experiment in the presence of L. terrestris (n = 12, two of the 14 individuals did not feed on litter; Fig 5). On average, roughly half of the litter material (52%) was consumed after 15 days, and only 15% of the litter material remained after 23 days (end of the experiment). The persistence time of litter differed significantly between microcosms with and without L. terrestris (Table 3; S1 Statistics, S1.7).

Bottom Line: Lumbricus terrestris preferred to consume legume litter over litter of the other plant functional groups.Pulling live plants into earthworm burrows might induce microbial decomposition of leaves to make them suitable for later consumption.Herbivory on plants beyond the initial seedling stage may only play a minor role in earthworm nutrition and has limited potential to influence plant growth.

View Article: PubMed Central - PubMed

Affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany.

ABSTRACT

Background: Recent studies suggested that the earthworm Lumbricus terrestris might act as a seedling predator by ingesting emerging seedlings, and individuals were observed damaging fresh leaves of various plant species in the field. To evaluate the significance of herbivore behavior of L. terrestris for plant and earthworm performance we exposed 23- to 33-days-old seedlings of six plant species to earthworms in two microcosm experiments. Plants belonged to the three functional groups grasses, non-leguminous herbs, and legumes. Leaf damage, leaf mortality, the number of leaves as well as mortality and growth of seedlings were followed over a period of up to 26 days. In a subset of replicates 0.1 g of soil surface litter of each of the six plant species was provided and consumption was estimated regularly to determine potential feeding preferences of earthworms.

Results: There was no difference in seedling growth, the number of live seedlings and dead leaves between treatments with or without worms. Fresh leaves were damaged eight times during the experiment, most likely by L. terrestris, with two direct observations of earthworms tearing off leaf parts. Another nine leaves were partly pulled into earthworm burrows. Lumbricus terrestris preferred to consume legume litter over litter of the other plant functional groups. Earthworms that consumed litter lost less weight than individuals that were provided with soil and live plants only, indicating that live plants are not a suitable substitute for litter in earthworm nutrition.

Conclusion: Our results demonstrate that L. terrestris damages live plants; however, this behavior occurs only rarely. Pulling live plants into earthworm burrows might induce microbial decomposition of leaves to make them suitable for later consumption. Herbivory on plants beyond the initial seedling stage may only play a minor role in earthworm nutrition and has limited potential to influence plant growth.

Show MeSH
Related in: MedlinePlus