How Do You Like Your Eggs?

 ‘Crawdads’, ‘mudbugs’, or ‘yabbys’ live extraordinary lives, digging deep burrows to the water table and surviving hundreds of meters away from permanent water sources! They churn up the soil, bringing back leached nutrients to support plant life, aerate the soil, and act as a tasty snack for several birds, mammals, and reptiles. Burrowing crayfish are key resources in many ecosystems across the planet, and yet their secretive lifestyles mean we know very little about them. Luckily, within the impressive ~6000 crayfish vouchered in the Smithsonian Invertebrate Zoology collection, there are several burrowing species that can help us fill some of those knowledge gaps.  

This summer I conducted research on the North American burrowing crayfish specimens that had been vouchered in the NMNH collections with their eggs intact. Life history data, like reproductive investment, have historically been lacking from our species descriptions and studies. Yet, these data are critical for conservation assessments and identifying what species require protection under governances like the Endangered Species Act. Currently no burrowing crayfish have been granted federal protection, despite many being considered endangered under state laws. In part, this is due to the paucity of data to evaluate burrowing crayfish conservation status; as many as 20% of burrowing crayfish are listed as data deficient under the IUCN red list, with a further 13% of species not yet evaluated. The  research  involved taking key measurements like clutch size, egg diameter, and body size from these ovigerous females. These data will allow us to better understand population dynamics of crayfish communities. We can use these data to predict population growth and which species may be experiencing population declines that require protective action. Furthermore, the goal is to understand the relationship between reproductive investment and geographic range size. With the difficulty of sampling burrowing crayfish and establishing their range, evaluating species from reproductive traits would provide an easier, more efficient method to determine conservation status. Synthesizing these data will support future conservation assessments and hopefully help to prioritize listing some of the narrowly endemic species that are at risk.  

This fellowship provided an amazing development opportunity to gain experience in the largest crayfish collection in the US and examine specimens of species that are rare and difficult to source, including museum lots from Australia and Madagascar. Some of the most impressive specimens included a Twospot Crayfish with over 700 eggs and two amazing intersex crayfish that will be the focus of some future studies! While at the museum I also had the opportunity to examine several potential mis-identifications that had been highlighted by our recent development of the online American Crayfish Atlas. I was able to examine several uncatalogued lots from six states in the western United States, and I may even have found a new species (stay tuned!). I had the opportunity to participate in a crayfish educational outreach event in the Ocean Hall at the Natural History Museum, with fellow PhD student Patrick Allison. At this event, we estimated at least 100 visitors were able to see crayfish specimens, learn about identification through dichotomous keys, and understand the danger of invasive crayfish species in DC, Maryland, and Virginia.  

The opportunity to explore the largest and oldest crayfish collection in the country was amongst the best experiences I’ve had during my PhD. So, when I’m asked ‘how do you like your eggs?’, I think of the hundreds of specimens vouchered here in the Smithsonian museum and I have to say…pickled! 

Caitlin Claire Bloomer | READ MORE

Originally from Ireland, Caitlin Bloomer completed an undergraduate degree in Marine Biology at the University of St Andrews in Scotland. She then  made the big jump across the pond to join the University of Illinois at Urbana-Champaign! Bloomer is currently a PhD Candidate studying Natural Resources and Environmental Sciences in Dr Chris Taylor’s lab with the Illinois Natural History Survey. Her  work focuses on the distributional drivers of burrowing crayfish, from broad environmental factors to specifics like their diet. Bloomer has  travelled around Missouri, Arkansas, and Kentucky examining some amazing and beautiful crayfish. This year, She  was awarded the Kenneth Jay Boss Fellowship in Invertebrate Zoology which allowed her to spend the summer in the National Museum of Natural History working on her  project ‘Evaluating the reproductive investment of US burrowing crayfishes’. Bloomer  hopes to continue her work with crayfish conservation in the future, and maybe even make a return trip to see her  favourite specimens at NMNH!