Identifying the differences in survivorship and growth in offspring of large and small females in the pipefish species Syngnathus scovelli
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While maternal investment in many fish species is well studied, the effect of maternal investment on offspring quality in the sex-role-reversed pipefish Syngnathus scovelli has not yet been determined. Previous studies in other species of pipefish have looked at egg size and components of an egg’s makeup as indicators of offspring quality and have found conflicting results. In this study, we compared growth and survivorship of offspring from females of different sizes by mating a controlled sized male with a large or small female and measuring growth every ten days. Using the number of eggs transferred by each female to her mate as a predictor of female reproductive success, we found that in a single mating there is no difference in the number of eggs or surviving offspring at birth for the two female size categories. The size at birth of the offspring were not significantly different but showed a trend towards larger females having longer offspring at birth. Growth and survivorship of offspring of large and small females was also compared when offspring are put into resource limited environments by having three levels of feeding for offspring from each brood. The results showed that offspring of both female categories had decreased growth and survivorship in the lowest food treatment and had similar growth and survivorship in the control. However, the experiment showed an unexpected result in the low feeding treatment where the offspring of small females grew more and had a higher survivorship than offspring of large females in the same feeding treatment. We hypothesize that the increased growth in offspring of small females when food is limited is a result of increased female provisioning from the smaller females who are compensating for their lower mating successes compared to larger females. These results may indicate that size of maternal female is not a definite indicator of offspring fitness and there are many interactions and environmental conditions that need to be taken into account in order to predict the future fitness of offspring in Gulf pipefish.
Martinez Aguirre, Andrea (2015). Identifying the differences in survivorship and growth in offspring of large and small females in the pipefish species Syngnathus scovelli. Honors and Undergraduate Research. Available electronically from