Table 3.
Time and materials associated with eDNA (via quantitative PCR) and classical necropsy approaches to determine Ribeiroia ondatrae status (presence and quantity) for a single field site. All costs are in U.S. dollars.
| eDNA | Traditional field sampling | |
|---|---|---|
| Time (h) | ||
| Permits (vertebrate use) | n/a | 2 |
| Field sample collection | 0.8 (5 water subsamples @ 10 min each) |
1 (18 amphibians) |
| Sample processing1 | 0.5 (DNA extraction, q-PCR, and results interpretation) |
3 (18 hosts @ 10 min each necropsy) |
| TOTAL TIME | 1.3 | 6 |
| Labor subtotal | $26 (1.33 h @ $20/h) | $120 (6 h @ $20/h) |
| Transportation2 | ||
| FedEx economy (by weight) | $37 (0.5 kg from S ON to MB) $76 (0.5 kg from CA to MB) |
$37 (1 kg from S ON to MB) $87 (1 kg from CA to MB) |
| Transportation subtotal | $57 (mean) | $62 (mean) |
| Consumable materials3 | ||
| Preservatives | $4 (50 mL ethanol for 5 subsample containers) |
$8 (100 mL ethanol for 15 specimens) |
| DNA extraction & PCR4 | $12 | n/a |
| TOTAL COST | $95 | $190 |
1
Ten sites (5 subsamples each) with standards can be run at once as thermal cycler can hold 96 samples. Per site time calculated by dividing total processing time for 96 samples (5 h) by 10.
2
Based on field sites and sample processing locations in current study (S ON = southern Ontario, MB = Manitoba, CA = California)
3
Re-usable equipment excluded (e.g. sweep nets, hand-held filtration units, thermal cycler)
4
See text for specific quantities and products used