Abstract
Author(s): Tobin, Mark E.; Koehler, Ann E.; Sugihara, Robert T.; Engeman, Richard M. | Abstract: Black rats (Rattus rattus) cause extensive damage in Hawaiian macadamia (Macadamia integrifolia) orchards. In a previous study, extensive and persistent snap trapping significantly reduced rat populations and depredations on developing macadamia nuts, but had little effect on subsequent yields of mature nuts. This suggested that macadamia trees may compensate for rat damage, and that commonly used indices based on rodent activity and proportion of nuts damaged may overestimate the impact of rodent depredations and exaggerate the effectiveness of control measures. To clarify the effects of rat feeding on developing macadamia nuts, two levels of damage at two times during nut development and evaluated yields of mature nuts were simulated. Both number of nuts per raceme (P = 0.0001) and total weight of mature kernels per raceme (P = 0.0001), but not mean weight per mature kernel (P = 0.90), varied among treatments. Both number of nuts and total weight of kernels decreased (P l 0.05) with increasing damage. Time during nut development that damage was simulated had no apparent effect (P g 0.05) on yields. These results indicate that racemes did not compensate for damage by retaining other nuts on the same raceme that might otherwise have dropped prematurely. A variance component analysis was also conducted to determine how best to sample the orchard in a practical fashion while minimizing potential sources of bias and retaining sensitivity for distinguishing among treatment effects. All of the random variability in the number of nuts per raceme and total weight of nuts per raceme, and g 93% of the variability in mean weight per mature nut were due to variability between racemes on a tree. Thus, blocking was not needed to control for variability among the different areas in the orchard; sampling fewer trees and concentrating available resources on measuring more racemes per tree would have provided a more sensitive comparison of treatments. Focusing on entire branches or trees instead of racemes as experimental units might have provided a more realistic model for investigating compensatory mechanisms in macadamia trees.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 11
Claim · model-written summary
Mature nut number per raceme varied among simulated-damage treatments.
.JPG?width=60){kind=small}
MacadamiaNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.JPG?width=500)
Verbatim
e0“Both number of nuts per raceme (P = 0.0001) and total weight of mature kernels per raceme (P = 0.0001), but not mean weight per mature kernel (P = 0.90), varied among treatments.”
t0“Macadamia”
Claim · model-written summary
Mature kernel weight per raceme varied among simulated-damage treatments.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both number of nuts per raceme (P = 0.0001) and total weight of mature kernels per raceme (P = 0.0001), but not mean weight per mature kernel (P = 0.90), varied among treatments.”
t0“Macadamia”
Claim · model-written summary
Mean weight per mature kernel did not vary significantly among treatments.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not mean weight per mature kernel (P = 0.90), varied among treatments.”
t0“Macadamia”
Claim · model-written summary
Nut number declined with increasing simulated damage.
- Treatment
- increasing damagee0
- Interactor
- Black rats
Rattus rattuse1pest - Outcome
- number of nutse0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both number of nuts and total weight of kernels decreased (P l 0.05) with increasing damage.”
t0“Effects of Stage of Nut Development and Simulated Rat Damage onMacadamia Yields”
e1“Black rats (Rattus rattus) cause extensive damage in Hawaiian macadamia (Macadamia integrifolia) orchards.”
Claim · model-written summary
Total kernel weight declined with increasing simulated damage.
- Treatment
- increasing damagee0
- Interactor
- Black ratsRattus rattuse1pest
- Outcome
- total weight of kernelse0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both number of nuts and total weight of kernels decreased (P l 0.05) with increasing damage.”
t0“Effects of Stage of Nut Development and Simulated Rat Damage onMacadamia Yields”
e1“Black rats (Rattus rattus) cause extensive damage in Hawaiian macadamia (Macadamia integrifolia) orchards.”
Claim · model-written summary
Timing of simulated damage had no apparent effect on yield.
- Treatment
- Time during nut development that damage was simulatede0
- Outcome
- yieldse0
- Direction
- no apparent effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Time during nut development that damage was simulated had no apparent effect (P g 0.05) on yields.”
t0“Macadamia”
Claim · model-written summary
The authors infer that racemes did not compensate for damage by retaining other nuts.
- Organ / stage
- racemese0
- Outcome
- did not compensate for damagee0
- Qualifier
- retaining other nuts on the same racemee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“racemes did not compensate for damage by retaining other nuts on the same raceme that might otherwise have dropped prematurely.”
t0“Macadamia”
Claim · model-written summary
All random variation in nut number and total nut weight per raceme was between racemes on a tree.
- Organ / stage
- racemese0
- Outcome
- random variability in the number of nuts per raceme and total weight of nuts per racemee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All of the random variability in the number of nuts per raceme and total weight of nuts per raceme, and g 93% of the variability in mean weight per mature nut were due to variability between racemes on a tree.”
t0“Macadamia”
Claim · model-written summary
At least 93% of variation in mean mature nut weight was between racemes on a tree.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“g 93% of the variability in mean weight per mature nut were due to variability between racemes on a tree.”
t0“Macadamia”
Claim · model-written summary
The authors recommend sampling more racemes per tree and fewer trees to distinguish treatment effects.
- Outcome
- sampling fewer trees and concentrating available resources on measuring more racemes per treee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sampling fewer trees and concentrating available resources on measuring more racemes per tree would have provided a more sensitive comparison of treatments.”
t0“Macadamia”
Claim · model-written summary
The authors suggest branches or trees as experimental units to study compensation more realistically.
- Outcome
- Focusing on entire branches or trees instead of racemes as experimental unitse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Focusing on entire branches or trees instead of racemes as experimental units might have provided a more realistic model for investigating compensatory mechanisms in macadamia trees.”