I was wondering if the reason there are so few, perhaps only just one so far, is that since eruvin are mainly d'rabbanan, there will not be a taku on these laws. If so, perhaps in mesechet Megilah, there may also not be many takus.
Shlomo Zalman Lerner, Atlanta, USA
I am not sure how much there is to read into this, as Teiku does appear in Eruvin three times (46b, 90a, 99a) regarding Rabbinic laws. Additionally, in a similar size Meseches such as Sanhedrin it applies only five times, even though many laws discussed there are Torah laws. I therefore do not think there is any conclusive reason for the amounts of Teikus.
All the best,
Yaakov Montrose