Academic journal article North American Journal of Psychology

Do Not Pet the Crawfish: Starting an Invertebrate Behavioral Lab

Academic journal article North American Journal of Psychology

Do Not Pet the Crawfish: Starting an Invertebrate Behavioral Lab

Article excerpt

Historic sources e.g. (A.P.A., 2007; Norcross, Sayette, Stratigis, & Zimmerman, 2014) extol the virtues of undergraduate behavioral research with animals in a laboratory (e.g. such training is favored by graduate school selection committees). In past decades, faculty and students in our psychology department at a south Louisiana university maintained a "rodent lab" where students learned about the care and handling of lab animals, participated in faculty research, and, in some instances, designed, conducted and published their own studies.

The department has been without a lab for several years due to retirements and funding cutbacks. Restarting a viable rodent lab requires considerable financial resources and Herculean effort. Given these considerations our lab has transitioned away from small mammals to invertebrate research.

In an editorial, Brembs (2013) provided a rationale for using invertebrates for experimental study. He cited examples of using invertebrate responses as an analog for more complex behavioral systems (reductionism) (Brembs, 2013). Finding simpler ways of explaining phenomena enables us to understand complexities and provides opportunities to study parallel mechanisms. After considerable deliberation and a brief foray into a "Ladybug Lab," we had a flash of insight: "Crawfish!"

This article describes our experiences over the past two years in founding our undergraduate crawfish lab, a practical, cost-effective alternative to behavioral research with vertebrates. Now that the lab is well-established we can offer interested colleagues insights that might prevent a "Crawpocalypse" in future labs. Mistakes that we made, as well as useful tips on how to prepare tanks, populate and maintain a healthy colony will be discussed. (1)

Early Lessons.

Rough start. After acquiring a donated 20 gallon tank, we bought a power filter, gravel, heater, dip net, water conditioner/dechlorinator, a few (1"x 5") PVC pipes, a 1/4 inch galvanized wire mesh as an aquarium hood, sinking spirulina food pellets for freshwater invertebrates (Aquatic Arts, USA), a siphon to clean the gravel (TERA PUMP[C] Genuine Aquarium Cleaner with Long Nozzle) and a timer for the lights (Model 63-864, Radio Shack, USA).

"Slough" crawfish (P. fallax), common to Louisiana and nearby states, are widely available by the sack. As the first tank was a pilot, a sack crawfish was put in; it scurried into a pipe and hid. For about a week, students fed it and observed its behavior. Crawfish are nocturnal, but especially when fed, do venture into the light. Crawfish are highly mobile and agile creatures; ours climbed up the heater cord and out of the tank. Lesson learned, crawfish are escape artists and lids are a must!

Our next lesson followed shortly thereafter when we added a second crawfish to the tank. It scurried into another pipe seemingly safe and sound. Flush with success, well on our way towards the inevitable self-sustaining Craw-colony, we left.

The next day we observed a horrific Gotterdamme-craw. Claws, carapaces, and antennae scattered in a watery killing-field! "Craw 1" had killed "Craw 2"; sack crawfish are highly territorial and aggressive!

Choosing the right crawfish and several cauCrawtions.

The solution was the discovery of P. virginalis (a.k.a. Marmorkrebs" or "Marbled Crawfish") which are remarkably docile. "Crawtion#1": MARBLED CRAWFISH ARE AN INVASIVE SPECIES AND MUST NOT BE RELEASED INTO THE WILD. IF YOU CANNOT SAFEGUARD AGAINST THIS, FIND ANOTHER INVERTEBRATE. THEY ARE ALSO ILLEGAL IN PLACES LIKE MISSOURI, TENNESEE AND THE EUROPEAN UNION. Marmorkrebs are relatives of "slough" crawfish, Aquatic Arts, (2019) notes that Marmorkrebs are "an all-female mutation that continually produces its own fertilized [sic] eggs, which develop into exact clones of the mother"; of course it is parthenogenesis that takes place in the female crawfish. The eggs are not actually fertilized. …

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