Early nutritional conditions, growth trajectories and mate choice: does compensatory growth lead to a reduction in adult sexual attractiveness?

Abstract

It is well documented that poor early nutrition can have profound negative effects on adult life-history traits. However, it has also been demonstrated that organisms can undergo compensatory resource allocation strategies (such as an accelerated growth rate) if food availability improves, so as to mitigate the effects of the poor early conditions. Previous research has indicated that elevated growth rates can incur costs in the longer term, such as an increased rate of senescence and shorter lifespan. We tested whether a phase of compensatory growth after a period of reduced food availability earlier in life affected the sexual attractiveness of adult male green swordtails Xiphophorus helleri, a species in which it has previously been documented that females prefer larger-bodied and longer-tailed males. The experiment compared the attractiveness of size-matched brothers that had experienced contrasting growth trajectories as juveniles; the experiments were initially conducted in the middle of a male’s sexually reproductive life and were then repeated towards the very end of life. At both ages, males that had undergone compensatory growth were equally as attractive as their brothers that had grown normally. These results suggest that the growth compensation benefits males through an increase in their attractiveness over that which they would have had if they had remained on their original growth trajectory. The lack of change in relative attractiveness with age indicates that the compensation does not cause greater deterioration in secondary sexual characters at older ages than in continuously well-fed males.