by Cheyenne Tait – My google searches betray me, clearly showing that I have a tough time turning off my scientific curiosity in everyday life. A small sample:
- Are cockroaches territorial? (three cockroaches are always on/under the chalkboard near the canteen when I walk past late at night, leaving the lab)
- Do spiders have pheromones? (the large spider that I tolerate in my bathroom suddenly gained upwards of 5 smaller individuals on the edges of her web)
- When bats yawn, does it signal anxiety? (a small group of bats was above me as I waited for the elevator, and as I stared at them, they seemed to start yawning)
I think it’s easy to be curious on a campus like that of NCBS, here in Bangalore, which is full of living things, as I tend to have a naturalist’s eye – and I’m in the right lab for that, too, the NICE lab, where the “N” is for naturalist.
I’ve come to realize that this curiosity is also why I push on in my PhD studies. I don’t “just” want the degree. Even if no one else cares about how odor preference shifting has led to genetic and neurobiological changes in the apple maggot fly, I want to know. I almost have to know. And I can’t simply google it, like the cockroaches, bats, and spiders, so I carry on. I continue in the lab, even when the setbacks make it seem like the project may never be finished, my question left unanswered for the next graduate student to tackle, with my curiosity eating me alive.
Often I take a brief break from my own research to redirect my curiosity, to use google and see if I can find some answers to my most recent naturalist’s questions (a list that is always growing, never becoming shorter).
(1) Cockroaches are not territorial (as in, staying in and defending one area) but rather gregarious, grouping together to rest, often finding each other using odor1. These odors, aggregation pheromones, may cross species barriers2, so if you see a group of them together, they may not even be the same species! Furthermore, the cockroaches that I see on the wall late at night, always three of them, are unlikely always to be the same individuals, especially not over several months. A study on the population genetics of cockroaches in an apartment complex has shown that within a particular building there is panmixia – everything is reproducing together, everything is mixing, therefore all cockroaches are able to pass through the entire building equally well and pass on their genetic material3.
(2) Yes of course spiders have sex pheromones4. This form of communication has not been as well studied in spiders as in other insects. However, even “exemplary loners”, as spiders are, must find each other for mating, and they can do this with airborne pheromones for long distance attraction, even in barren locations like deserts5. Courtship then requires additional cues, such as contact pheromones (cuticular hydrocarbons), and specific behaviors that the visually-guided spiders can respond to in stereotyped ways4. Additionally, a female spider’s web itself can be coated with a pheromone to attract males6. So even if I removed the spider in my room from her web, small males could continue to be attracted to it from near and far!
(3) I thought that yawning could be a signal of anxiety in the bats I saw on the ceiling by the elevator, because I thought maybe I was stressing them out by standing there, and because it’s well known to be such a signal of tension in dogs7 and primates such as baboons8 (those species also show social “contagious” yawning, like we do, but that is not the type of yawn I’m talking about here). However, bat yawning is an even less researched field than cockroach aggregation and spider pheromones (who could have guessed?). The only studies I could find easily don’t say anything about yawning indicating stress or tension in the bats. Instead yawning in male bats seems to be a way to expose scent glands and release odors that have roles in social behaviors9,10. So I think I’m happy about this finding – the yawning wasn’t a sign I disturbed the bats by observing, it was just the bats being bats!
Curiosity assuaged, I now must try to pull myself away from the abyss that is google scholar. The natural world is so interesting, there’s so much to know, so little time!
- Ame et al. 2004, “Cockroach aggregation based on strain odour recognition”, Animal Behaviour
- Bell et al. 1972, “Cockroach Aggregation Pheromones: Analysis of Aggregation Tendency and Species Specificity”, Journal of the Kansas Entomological Society
- Crissman et al. 2010, “Population Genetic Structure of the German Cockroach in Apartment Buildings”, Journal of Medical Entomology
- Gaskett 2007, “Spider sex pheromones: emission, reception, structures, and functions”, Biological Reviews
- Papke et al. 2001, “An airborne female pheromone associated with male attraction and courtship in a desert spider”, Animal Behaviour
- Kasumovic and Andrade 2004, “Discrimination of airborne pheromones by mate-searching male western black widow spiders: species and population-specific responses”, Canadian Journal of Zoology
- Frank et al. 2007, “Puppy behaviours when left home alone: A pilot study”, Applied Animal Behaviour Science
- Castles et al. 1999, “Social anxiety, relationships, and self-directed behavior among wild female olive baboons”, Animal Behaviour
- Voigt-Heuke et al. 2010, “A dual function of echolocation: bats use echolocation calls to identify familiar and unfamiliar individuals”, Animal Behaviour
- Voigt and Helversen 1999, “Storage and display of odour by male Saccopteryx bilineata”, Behav Ecol Sociobiol