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2. Nitrogen turnover of Sinella coeca (Collembola: Entomobryidae)
- Creator:
- Bakonyi, Gábor
- Type:
- article, model:article, and TEXT
- Subject:
- Collembola, Entomobryidae, Sinella coeca, digestion, nitrogen isotope, and nitrogen turnover
- Language:
- English
- Description:
- Adult collembolans we:re fed with two different food types. Leaves of Taraxacum officinale and Dactylis glomerata were given as food sources in two physical forms: either as intact leaves or as powder. Foods were labelled with 15N. The 15N uptake curves were measured. Turnover rates and turnover times were calculated. Results show that Taraxacum leaves are preferred to Dactylis leaves. The physical condition of the leaves influenced the nitrogen turnover of the animals to a large extent. Fragmentation of Dactylis leaves enhanced nitrogen utilization by roughly two-fold and decreased turnover time by nearly half. Consumption of Taraxacum leaves has synergic effect on the nitrogen utilization of Dactylis leaves. Simultaneous consumption of Taraxacum and Dactylis enhanced the nitrogen uptake rate from Dactylis leaves compared to the treatment where Dactylis was the only food source.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
3. Utilization of the nutrients in the soluble and insoluble fractions of fungal mycelium by larvae of the stag beetle, Dorcus rectus (Coleoptera: Lucanidae)
- Creator:
- Tanahashi, Masahiko and Kubota, Kôhei
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, entomologie, entomology, Coleoptera, Lucanidae, Dorcus rectus, saproxylophagous insects, fungal cell wall, chitin, digestion, symbiotic microorganisms, Bjerkandera adusta mycelium, 2, and 59
- Language:
- English
- Description:
- Larvae of the stag beetle, Dorcus rectus, feed on decaying wood, which they digest with the aid of symbiotic yeasts; however, they can be successfully reared on artificial diets containing only fungal tissue. In this study we tested whether D. rectus larvae can utilize fungal cell walls, which are an insoluble component of mycelium. Lyophilized Bjerkandera adusta mycelium cultured in potato-dextrose liquid medium consisted of a 47.6% hot-water insoluble fraction by mass, which contains 53.7% of the total nitrogen in the mycelium. D. rectus larvae that hatched from surface-sterilized eggs were reared for 14 days on agar-based diets containing either the soluble fraction, insoluble fraction or both, extracted from 100 mg of mycelium. The larvae increased in mass most on the mixed diet, and there was no difference in their growth on the mixed and positive control diets. Both the soluble and insoluble fractions improved larval growth compared to the negative control diet; however, the growth rates were much lower than those expected from the nitrogen dose-growth response curve obtained in a previous study. Addition of b-chitin to the soluble fraction did not positively affect larval growth. Therefore, we conclude that (1) D. rectus larvae need both the soluble and insoluble fractions of mycelium and (2) the larvae digest the insoluble fraction using their own enzymes., Masahiko Tanahashi, Kôhei Kubota., and Seznam literatury
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public