Last Friday, Dr. Ryan Frankowiak, a professor from Queen’s University, gave a talk titled “Two sides of the same coin: Disentangling adult and offspring fitness components,” as part of UTM’s department of Biology’s “Biology Seminar Series.” Frankowiak’s seminar concerned the variance in reproductive fitness and its respective components that arise in mature adults compared to their offspring.
The principle of fitness itself is commonly defined in tandem with the phrase “survival of the fittest.” Individuals in a population that possess and can pass on beneficial traits will be more fit for their environment compared to other individuals in that same population.
Frankowiak chose to examine the Smallmouth Bass as a prime candidate for this avenue of research. Frankowiak explains that “it is native to North America, it is a territorial nest builder, [and] it has male parental care, so the female does not provide any care at all. They are thought to be socially monogamous, and they show considerable plasticity in life history characteristics.” These specific traits allowed for a research project to be built on examining how they relate to reproductive fitness. Certain fitness components that were specifically examined in relation to these traits included survival, mating success, fertility rate, and growth rate.
The first part of Frankowiak’s research focused on the “adult components of fitness.” The site of interest that was studied was Lake Opeongo, located in Algonquin National Park. In summary of his findings, it was found that “the mating system in [smallmouth bass] is monogamy, with a low rate of polygynandry. We do see multiple mating, but we suspect it may be constrained by the active parental care by males, and females not being able to get access to males that are actively defending their nests.” Because of this, it is suspected that there are restrictions on sexual selection that lead to a lack of sexual dimorphism.
Additionally, an important factor in Frankowiak’s research was “the natal philopatry” trends that smallmouth bass exhibit. While philopatry represents the tendency of an organism to return to an area consistently, natal philopatry concerns the tendency of animals to return to their original birthplace to produce offspring.
Frankowiak found that male smallmouth bass possess a very high tendency to stay within the nests that they originally build during mating season, while females are much more likely to move around between nests. This may be due to the habit of males to defend their territory.
To conclude Frankowiak’s research on adults, he examined the environment in which smallmouth bass live and how related factors affect reproductive fitness. He observed that “the difference in reproductive success was large as determined by the environment.” This supports the idea that smallmouth bass require a post-nesting season relatively free of turbulent or stressful conditions, as it is a critical time period for the species and their reproductive success.
Regarding research on the fitness patterns among offspring, Frankowiak explains that many guiding questions are present: “Do dispersal patterns differ among the families, or locations? Depending on where you are, or what family you belong to, do you move differentially? Do juveniles choose to remain near kin? […] or is it in fact due to philopatry? In terms of habitat occupancy, do these juveniles just distribute themselves along the shoreline randomly, or are they actively selecting areas that are most conducive to their growth and survivorship?” Researchers will continue to examine the reproductive fitness among juvenile smallmouth bass.
