picture of Bianca Marcellino

Bianca Marcellino MSc, published her first 1st authored paper in ScienceDirect

Please join us in congratulating Bianca Marcellino MSc, PI Rosalind Murray, as she published her first 1st authored paper: Too hot to handle: male dragonflies decrease time spent mating at higher temperatures in ScienceDirect 


Melanin is an important pigment that plays a key role in the colouration of animals, particularly known for its dark, rich colour expression and great variation in intensity from dark browns and blacks to lighter reds and oranges. This variation within the animal world has made it an important definer of sexual attraction whereby the animals (usually males) with the darkest and/or largest melanin patches are consider the most attractive and have greater mating success than their lighter counterparts under the force of sexual selection. Melanin also has the unique ability to absorb all visible light frequencies and reflect almost none, giving it important thermoregulatory properties as well. However, it’s role in thermoregulation is complicated by climate change increasing the amount of solar radiation retained on Earth, thus increase thermoregulatory demands under the force of natural selection. Therefore, a trade-off emerges between the time spent mating and the time spent thermoregulating, but where it now becomes unclear how males relying on melanin ornaments for mating will trade off with thermoregulation in terms of time spent on each type of behaviour. We looked at this system in the dragonfly Celithemis elisa where the males have wing melanin ornaments used in sexual selection, using field observations of behaviour and relating it to temperature and melanin level. Through analyzing these behavioural observations, we were able to determine that increasing temperature resulted in increased time spent thermoregulating as predicted, but this came at the expense of less time spent mating. Thus, this provides evidence for this trade-off such that the forces of natural selection (pushing increased thermoregulation) and sexual selection (favouring darker melanin ornaments) are not aligned. These results suggest that some species may be forced to reduce important life history events like mating effort, which could population-level implications for these species in the future, especially as climate change continues.

Bianca Marcellino - picture from paper

Bianca is an ecologist with experience in both terrestrial and aquatic systems. She completed her Honours Bachelor of Environmental Science in Ecology at the University of Guelph, continuing to acquire a Master of Science in Ecology and Evolutionary Biology from the University of Toronto, specifically looking at the impact of climate change on dragonfly behaviour and its implications for species persistence. Since joining the team in 2019, she has honed her field skills and broadened her experience through conducting a variety of wildlife and vegetation surveys throughout Ontario including: breeding bird, bat habitat and acoustic, anuran call, Ecological Land Classification (ELC), dragonfly and butterfly, and benthic invertebrate stream quality surveys. Guided by her expertise in dragonflies, Bianca has played a significant role in sampling benthic invertebrates from streams of the Laurel Creek watershed and using environmental DNA (eDNA) inventory results to quantify watershed‐scale habitat quality.


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