Differential Allocation by Female Zebrafish (Danio rerio) to Different-Sized Males – An Example in a Fish Species Lacking Parental Care

Abstract

Organisms allocate resources to reproduction in response to the costs and benefits of current and future reproductive opportunities. According to the differential allocation hypothesis, females allocate more resources to high-quality males. We tested whether a fish species lacking parental care (zebrafish, Danio rerio) expresses male size-dependent differential allocation in monogamous spawning trials. In addition, we tested whether reproductive allocation by females is affected by previous experience of different-quality males, potentially indicating plasticity in mate choice. To that end, females were conditioned to large, small or random-sized males (controls) for 14 days to manipulate females' expectations of the future mate quality. Females showed a clear preference for large males in terms of spawning probability and clutch size independent of the conditioning treatment. However, when females experienced variation in male size (random-sized conditioning treatment) they discriminated less against small males compared to females conditioned to large and small males. This might suggest that differential allocation and size-dependent sexual selection is of less relevance in nature than revealed in the present laboratory study.

Size‐selective harvesting fosters adaptations in mating behaviour and reproductive allocation, affecting sexual selection in fish

“…Different fertilization rates in relation to personality and size have been previously documented in zebrafish (e.g. Ariyomo & Watt, , Vargas et al, ), which can be both a function of females releasing eggs of differing quality based on perceived male quality and male performance (Ariyomo & Watt, ; Uusi‐Heikkilä, Böckenhoff, et al, ; Uusi‐Heikkilä, Kuparinen, et al, ). Both female and male traits are likely under selection and could have responded to five generations of intensive large size‐selective harvesting (Baulier, Morgan, Lilly, Dieckmann, & Heino, ; Uusi‐Heikkilä et al, ), providing two main explanations for our results.…”

“…We did this in an effort to disentangle the effect of a behaviourally mediated mechanism from size effects. However, in zebrafish and in many other species, body size is a key trait under selection (Pyron, ; Uusi‐Heikkilä, Böckenhoff, et al, ; Uusi‐Heikkilä, Kuparinen, et al, ). It is possible that the adaptations seen in our experiment in the large‐harvested line could be reversed when the generally smaller individuals of this line meet with the larger members of the other two lines.…”

The evolutionary legacy of size‐selective harvesting extends from genes to populations

“…Furthermore, zebrafish females allocate more reproductive resources to more preferred, large males (Uusi‐Heikkilä et al. ), and because in large‐selected line males were generally larger, large‐selected females could have released more eggs toward them compared to random line, where fewer females were coupled with a large male.…”

“…In addition, the model did not incorporate the potential effects of dominance hierarchies and female differential allocation on zebrafish reproductive output (Uusi‐Heikkilä et al. ). Moreover, model results were based on the assumption that the parameters for growth, maturation, and reproductive investment that we measured in the laboratory would translate to field conditions.…”

Towards a Comprehensive Catalog of Zebrafish Behavior 1.0 and Beyond

“…94 1.25. Cannibalism: Eating of dead or alive conspecifics (also see Infanticide, including egg cannibalism 95 ). 1.26.…”