Predation by Terrestrial Isopods

Edney, E. B.; Allen, W. Archer; McFarlane, J. A.

doi:10.2307/1935231

Cited by 23 publications

(8 citation statements)

References 10 publications

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“…In summary, the digestive capabilities of T. rathkei are similar to those reported for other terrestrial detritivores with omnivorous feeding habits (Nielsen 1962(Nielsen , 1963Swift et al 1979;Taylor 1982), including related species of terrestrial isopods (Paris 1963;Hartenstein 1964;White 1968;Edney et al 1974;Shachak et al 1976).…”

Section: Isopod and Leaf Litter Carbohyandasessupporting

confidence: 79%

The effect of acquired microbial enzymes on assimilation efficiency in the common woodlouse, Tracheoniscus rathkei

Kukor

Martin

1986

Oecologia

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The digestive tract of the common woodlouse, Tracheoniscus rathkei Brandt (Isopoda: Oniscoidea), contains digestive enzymes active against α-1,4-glucans, which are the chief storage polysaccharides of vascular plants, algae, fungi, and animals, and β-1,3-glucans, which are present in algae and fungi. Digestive tract extracts also exhibit significant activity toward xylan and carboxymethyl-cellulose but negligible activity toward microcrystalline cellulose, substrates representative of the major structural polysaccharides of vascular plants. Low activity was detected toward pectin, and no activity was detected toward chitin. Activity toward xylan is due in part to microbial enzymes acquired from the leaf litter which was the isopod's normal food. Although ingested microbial xylanases are stable and active in the gut fluid, they do not make a quantitatively significant contribution to the isopod's ability to assimilate the hemicellulosic component of its diet. However, the assimilation of carbon from labeled plant fiber is enhanced in isopods which have acquired a cellulase by ingestion of leaf litter amended with a commercial preparation of the cellulase complex from the fungus, Penicillium funiculosum. This result demonstrates the potential contribution of acquired enzymes to the digestion of plant fiber in terrestrial detritivores. We urge caution, however, in assigning an important digestive function to ingested enzymes on the basis of evidence that only indicates that such enzymes are present in the gut fluid without additional evidence that their presence results in an enhancement of digestive efficiency.

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Section: Isopod and Leaf Litter Carbohyandasessupporting

confidence: 79%

The effect of acquired microbial enzymes on assimilation efficiency in the common woodlouse, Tracheoniscus rathkei

Kukor

Martin

1986

Oecologia

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“…These experiments deliberately isolated litter processing by P. scaber from other effects that the isopod may have on soil food webs. Macroscopic soil invertebrates, such as isopods, millipedes and earthworms, often have considerable effects on the physical structure of the soil (‘bioturbation’, Scheu & Setälä 2001), and isopods are also known to feed on live plants (Paris & Sikora 1965) and other invertebrates (Edney, Allen & McFarlane 1974). Bacterivorous and predaceous nematodes may, therefore, be negatively affected by P. scaber through other mechanisms excluded from these experiments by the absence of live isopods.…”

Section: Discussionmentioning

confidence: 99%

Facilitation and predation structure a grassland detrital food web: the responses of soil nematodes to isopod processing of litter

Bastow

2011

Journal of Animal Ecology

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Summary1. Detritus can support successive consumers, whose interactions may be structured by changes in the condition of their shared resource. One model of such species interactions is a processing chain, in which consumers feeding on the resource in a less processed state change the resource condition for subsequent consumers. 2. In a series of experiments, the hypothesis was tested that a common detritivore, the terrestrial isopod Porcellio scaber, affects soil nematodes through the processing of plant litter. Different detrital resources were added to soil from a California coastal prairie in order to simulate litter processing by the detritivore. Treatments that included only whole grass litter corresponded to detrital food webs lacking detritivores, while treatments that included mixtures of P. scaber faeces and grass litter corresponded to different densities or feeding rates of P. scaber. 3. Simulated litter processing by P. scaber increased the abundance of bacterivorous nematodes by between 32% and 202% after 24-44 days in laboratory experiments, but had no effect on fungivorous or predaceous nematodes. 4. In a subsequent field experiment, however, fungivorous nematodes were suppressed by isopod litter processing while bacterivores showed no response. Instead, P. scaber processing of litter increased the abundance of predaceous nematodes in the field experiment by 176%. 5. When simulated litter processing of litter was crossed in laboratory experiments with predaceous nematode addition (comparable to the response of predators in the field experiment), the abundance of bacterivores was increased by isopod processing of litter (by an average of 122%), but suppressed by elevated densities of predaceous nematodes (by an average of 41%). 6. This suggests that litter processing by P. scaber facilitates the bacterial channel of the soil food web, but that predaceous nematodes suppress the response of bacterivores in the field. Processing chain interactions may, therefore, be important in understanding the relative importance of bacterial and fungal channels in the soil food web, while top-down effects of predators determine the resulting changes in population abundance and biomass.

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“…To do so, we designed an experiment that increased the probability of predation and cannibalism for the woodlice [43]: Before putting predator and prey together, infected “prey” individuals were weakened by withdrawing a large amount of hemolymph while uninfected “predator” individuals were starved. Using this approach, all “prey” individuals were eaten by “predator” individuals within two days.…”

Section: Introductionmentioning

confidence: 99%

Cannibalism and Predation as Paths for Horizontal Passage of Wolbachia between Terrestrial Isopods

et al. 2013

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The alpha-proteobacteria Wolbachia are the most widespread endosymbionts in arthropods and nematodes. Mainly maternally inherited, these so-called sex parasites have selected several strategies that increase their vertical dispersion in host populations. However, the lack of congruence between the Wolbachia and their host phylogenies suggests frequent horizontal transfers. One way that could be used for horizontal Wolbachia transfers between individuals is predation. The aim of this study was to test whether horizontal passage of Wolbachia is possible when an uninfected terrestrial isopod eats an infected one. After having eaten Armadillidium vulgare harbouring Wolbachia, the predator-recipients (the two woodlice A. vulgare and Porcellio dilatatus dilatatus) that were initially Wolbachia-free were tested positive for the presence of Wolbachia both by quantitative PCR and Fluorescence in situ Hybridization (FISH). Even if the titers were low compared to vertically infected individuals, this constitutes the first demonstration of Wolbachia occurrence in various organs of an initially uninfected host after eating an infected one.

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Predation by Terrestrial Isopods

Cited by 23 publications

References 10 publications

The effect of acquired microbial enzymes on assimilation efficiency in the common woodlouse, Tracheoniscus rathkei

The effect of acquired microbial enzymes on assimilation efficiency in the common woodlouse, Tracheoniscus rathkei

Facilitation and predation structure a grassland detrital food web: the responses of soil nematodes to isopod processing of litter

Cannibalism and Predation as Paths for Horizontal Passage of Wolbachia between Terrestrial Isopods

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