Juvenile diet quality and intensity of sexual conflict in the mite Sancassania berlesei

Abstract

Background: Differing evolutionary interests of males and females may result in sexual conflict, whereby traits or behaviours that are beneficial for male reproductive success (e.g., traits related to male-male competition) are costly for females. Since sexual conflict may play an important role in areas such as speciation, population persistence or evolution of life history traits, understanding what factors modulate the intensity of sexual conflict is important. This study aims to examine juvenile diet quality as one of the underestimated ecological factors that may affect the intensity of sexual conflict via individual conditions. I used food manipulation during the development of the mite Sancassania berlesei to investigate the effects on male reproductive behaviour and competitiveness, male-induced harm to female fitness and female resistance to this harm.

Results: Males that were exposed to low-quality food started mating later than the control males, and number of their mating attempts were lower compared to those of control males. Moreover, males from the low-quality diet treatment sired fewer offspring under competition than males from the control treatment. However, the fitness of females exposed to males reared on a poor diet did not differ from that of females mated with control males. Furthermore, female diet quality did not alter their resistance to male-induced harm.

Conclusion: Overall, diet quality manipulation affected male reproductive behaviour and mating success. However, I found no evidence that the intensity of sexual conflict in S. berlesei depends on male or female conditions. Investigating a broader range of environmental factors will provide a better understanding of sexual conflict dynamics and its feedback into associated evolutionary mechanisms.

Keywords: Behavioural ecology; Condition dependence; Diet quality; Male-induced harm; Male-male competition; Sancassania berlesei; Sexual conflict.

Fig. 1

Effect of mating frequency on female lifespan. Kaplan-Meier survival plots for females maintained in high mating frequency and low mating frequency groups

Fig. 2

Effects of mating frequency on female reproductive output. Boxplots showing the distribution of the number of eggs laid (between the 6th and 11th days of the experiment) by females in the high mating frequency and low mating frequency treatments. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 3

The effect of male diet quality during development on time to start of first copulation. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 4

Effect of male diet quality during development on mating duration within 60 min of observation. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 5

Effect of male diet quality during development on the number of mating attempts within 60 min of observation. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 6

Effect of male diet quality during development on male competitiveness. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 7

Effect of male diet quality during development on female lifespan. Kaplan-Meier survival plots for females maintained with males in the high- and low-quality treatments

Fig. 8

Effect of male diet quality during development on female reproductive output. Boxplots showing the distribution of the number of eggs laid (between the 1st and 6th days of the experiment) by females mated with males in the high- and low-quality treatments. The box encloses values between the first and third quartiles of the data (the inter-quartile range, IQR), while the horizontal bar within the box indicates the median. Whiskers extend from the box to the largest/smallest values that are within 1.5Χ the IQR of the box. Values outside that range are outliers and are indicated by circles

Fig. 9

Effect of female diet quality during development on their reproductive output Mean number of eggs (=/− SE) laid by females (between the 1st and 6th days of the experiment) fed with high-quality food and low-quality food during development after 3 days of mating with males fed with high-quality food and low-quality food during development