I always enjoy reading about the evolution or anthropology of sleep because the general conclusions are often polarizing to those of the biomedical community; while we are interested in how a lack of sleep confers increased risks for physiological and behavioral pathologies, these research communities show how a lack of sleep confers increased access to resources, which in this particular case, were mates.
A paper published in this week’s issue of Science investigated the relationship between time spent asleep and mating success in the Artic-dwelling sandpiper. Through the use of radiotelemetry, which had to be terribly difficult to undertake (side note: I have done some telemetric sleep recording in a temperature-controlled, confined experimental unit, not in sub-freezing conditions with an experimental area covering miles), the researchers were able to monitor daily locomotor and sleep/wake activity. During mating season, the males and females go several days with less sleep for the purpose of finding and seeking out as many courtships and subsequent copulations as possible since the species is polygynous. To this end, a percent increase in activity was largely attributed to the presence of fertile, but not post-fertile sandpipers. And when the sandpipers did finally take a break from courting to sleep, there was an interesting interaction between the length of time spent in NREM sleep, sleep intensity, and sleep fragmentation discovered; sandpipers that were more determined to pursue had fewer amounts of daily NREM sleep with greater fragmentation, but of greater intensity compared with sandpipers that were taking it easy this season around. This observation is a classic example of sleep homeostasis; greater sleep intensity under conditions of partial or total sleep deprivation.
Since I just finished reading a book on the evolution and anthropology of human sexuality and the overlap with sexual and “relationship-like” practices in primates (It’s called Sex at Dawn by a wonderful couple [both authors of the book]), it got me thinking if this type of adaptation to seasonal mating is specific for the sandpiper, characteristic of polygynous species, or common to all non-monogamous (polyandrous and promiscuous) species?
Lesku JA, Rattenborg NC, Valcu M, Vyssotski AL, Kuhn S, Kuemmeth F, Heidrich W, & Kempenaers B (2012). Adaptive sleep loss in polygynous pectoral sandpipers. Science (New York, N.Y.), 337 (6102), 1654-8 PMID: 22878501