However, certain wasp species such as pollen wasps have similar behaviours, and a few species of bee scavenge from carcases to feed their offspring. The world's largest species of bee is thought to be the Indonesian resin bee Megachile pluto, whose females can attain a length of 39 millimetres (1.54 in).
For a Ph.D. in Psychology: Most Ph.D. programs require at least 5 to 7 years to complete. In addition to regular coursework, you may also be expected to complete an internship or supervised residency. The program usually culminates in completing an original research project or dissertation.
The PhD takes another 2-6 years after the masters. There's no set length for a PhD in the US-it's very common for it to take 4+ years after the masters. It depends on the degree you want, the requirements of the program (those are not standard), you, your motivation, your project, your adviser, and your committee.