Parental effects alter the adaptive value of an adult behavioural trait
- University of Cambridge, United Kingdom
- Australian National University, Australia
- Polish Academy of Sciences, Poland
- University of Zürich, Switzerland
Figures
Figure 1 with 2 supplements
Overview of the model structure, including mortality and survival (A) and reproduction (B).
https://doi.org/10.7554/eLife.07340.003
Figure 1—figure supplement 1
Longevity of adult virgin males (n = 43) and females (n = 50) (A) shown as a cumulative survival plot and (B) comparing mean ± S.E.M lifespan for each sex.
The rate at which the beetles died was not significantly different, nor was there a difference in their mean lifespan (X2 = 0.69, d.f. = 1, p = 0.41). These data were collected from an experiment in …
Figure 1—figure supplement 2
Frequency distribution of the size of field-caught N. vespilloides (shown in blue) and the experimental N. vespilloides described in this study (shown in red).
The size of the beetle is given by its pronotum width. There is no sexual size dimorphism, so the data for males and females have been pooled. Our experimental treatments generated beetles that were …
Figure 2
The effect of the mother's early-life environment on (A) brood mass at the dispersal stage of development and (B) her lifespan after reproduction.
Mothers raised cross-fostered broods of either 5 (white circles) or 20 larvae (black circles), singlehandedly. A poor quality environment in early life generates mothers that (A) are less effective …
Figure 3
The effect of the father's early-life environment on (A) brood mass at the dispersal stage of development and (B) his lifespan after reproduction.
Fathers raised cross-fostered broods of either 5 (white circles) or 20 larvae (black circles), singlehandedly. A poor quality environment in early life generates fathers that (A) are less effective …
Figure 4
The effect of the female's early-life environment (i.e., the duration of care she received as a larva) on her lifespan after reproduction (white bars), and on the lifespan of the male with whom she raised offspring (black bars).
All males developed in a high-quality environment. The greater the difference within the pair in the environment they each experienced during development, the greater the difference in their …
Figure 5
The relationship between the average care received by a brood and the strength of parental effects αF (i.e., the extent to which care received affects the future parental quality of offspring).
Average care levels increase with the strength of parental effects both when sexual conflict is present (circles) and when it is absent (squares). When there is no sexual conflict, parents provide …
Tables
Table 1
Results from Experiment 1: the influence of parental effects on the costs and benefits of parental care provided in adult life
| Female-only care | ||||
|---|---|---|---|---|
| Estimate | Standard error | t value | p value | |
| a. Effect on brood mass (benefit of care) | ||||
| Intercept | 0.07294 | 0.70654 | 0.103 | – |
| Duration of care as larva | −0.01430 | 0.09597 | −0.149 | 0.010 |
| Brood size raised as adult | 2.41542 | 0.08689 | 27.797 | <0.0001 |
| Carcass mass | 0.01451 | 0.01609 | 0.902 | 0.345 |
| Female pronotum | 0.12663 | 0.12270 | 1.032 | 0.282 |
| Duration of care as larva x brood size raised as adult | 0.44623 | 0.12150 | 3.673 | 0.0004 |
| Coefficient | Standard error | z value | p value | |
|---|---|---|---|---|
| b. Effect on maternal survival (cost of care) | ||||
| Duration of care as larva | 0.359 | 0.342 | 1.05 | 0.290 |
| Brood size raised as adult | 0.853 | 0.354 | 2.41 | 0.016 |
| Carcass mass | 0.059 | 0.059 | 1.00 | 0.320 |
| Female pronotum | 0.135 | 0.453 | 0.30 | 0.770 |
| Duration of care as larva x brood size raised as adult | −1.286 | 0.507 | −2.54 | 0.011 |
| Male-only care | ||||
|---|---|---|---|---|
| Estimate | Standard error | t value | p value | |
| c. Effect on brood mass (benefit of care) | ||||
| Intercept | 0.60553 | 0.25415 | 2.383 | – |
| Duration of care as larva | 0.04445 | 0.04307 | 1.032 | 0.0002 |
| Brood size raised as adult | 0.75672 | 0.03818 | 19.820 | <0.0001 |
| Carcass mass | 0.01880 | 0.00572 | 3.287 | 0.001 |
| Male pronotum | −0.01450 | 0.04675 | −0.310 | 0.785 |
| Duration of care as larva x brood size raised as adult | 0.20190 | 0.05406 | 3.735 | 0.0002 |
| Coefficient | Standard error | z value | p value | |
|---|---|---|---|---|
| d. Effect on paternal survival (cost of care) | ||||
| Duration of care as larva | 0.183 | 0.352 | 0.52 | 0.600 |
| Brood size raised as adult | 0.686 | 0.334 | 2.05 | 0.040 |
| Carcass mass | 0.076 | 0.053 | 1.42 | 0.160 |
| Male pronotum | −0.448 | 0.385 | −0.12 | 0.910 |
| Duration of care as larva x brood size raised as adult | −0.856 | 0.474 | −1.81 | 0.071 |
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Parental effects were created experimentally by exposing experimental subjects to either 0 hr or 24 hr of post-hatching care as larvae. They were then kept until adulthood and given broods of either 5 or 20 cross-fostered larvae to raise as a single parent. Their lifespan thereafter was recorded. Further details are given in the ‘Materials and methods’.
Table 2
Results from Experiment 2: the influence of parental effects on the outcome of a social interaction
| NB parental effect experienced by female | Coefficient | Standard error | z value | p value |
|---|---|---|---|---|
| a. Female lifespan | ||||
| Parental effect: 8 hr vs 0 hr | 0.427 | 0.228 | 1.88 | 0.061 |
| Parental effect: 24 hr vs 0 hr | 0.216 | 0.236 | 0.92 | 0.360 |
| Parental effect: 192 hr vs 0 hr | −0.073 | 0.254 | −0.29 | 0.770 |
| Total carcass mass | 0.017 | 0.016 | 1.06 | 0.290 |
| Total brood mass | 0.004 | 0.029 | 0.16 | 0.870 |
| Female pronotum | 0.522 | 0.322 | 1.62 | 0.110 |
| NB parental effect experienced by male's partner | Coefficient | Standard error | z value | p value |
|---|---|---|---|---|
| b. Male lifespan | ||||
| Parental effect: 8 hr vs 0 hr | −0.109 | 0.235 | −0.47 | 0.640 |
| Parental effect: 24 hr vs 0 hr | −0.664 | 0.252 | −2.63 | 0.008 |
| Parental effect: 192 hr vs 0 hr | −1.033 | 0.291 | −3.55 | 0.0003 |
| Total carcass mass | −0.027 | 0.023 | −1.17 | 0.240 |
| Total brood mass | −0.094 | 0.032 | −2.87 | 0.004 |
| Male pronotum | 0.915 | 0.366 | 2.50 | 0.012 |
| NB parental effect experienced by brood's mother | Estimate | Standard error | z value | p value |
|---|---|---|---|---|
| c. Brood size | ||||
| Intercept | 1.35776 | 0.39286 | 3.456 | 0.0005 |
| Parental effect: 8 hr vs 0 hr | 0.02350 | 0.03295 | 0.713 | 0.476 |
| Parental effect: 24 hr vs 0 hr | 0.16261 | 0.03453 | 4.710 | <0.0001 |
| Parental effect: 192 hr vs 0 hr | 0.14641 | 0.03676 | 3.983 | <0.0001 |
| Total carcass mass | 0.00765 | 0.00308 | 2.485 | 0.013 |
| Female pronotum | 0.31190 | 0.05133 | 6.076 | <0.0001 |
| Male pronotum | 0.12973 | 0.05729 | 2.265 | 0.024 |
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Parental effects were created experimentally by exposing females to 0 hr, 8 hr, 24 hr, or 192 hr of post-hatching care as larvae. They were then kept until adulthood and allowed to breed twice with a male who had received 192 hr of care as larva. The two parents raised offspring together. Each parent's lifespan thereafter was recorded, as was the mass of their brood at dispersal. Further details are given in the ‘Materials methods’.
