As far as I know, this is not very secret, but not fully studied either. There are various kinds of flying insects other than bees that are key pollinators. I

As far as I know, this is not very secret, but not fully studied either. There are various kinds of flying insects other than bees that are key pollinators. In avocados I believe there is still quite a bit of research to do about A type and B type flowers and pollinator insects. The current knowledge is that the flower opens as type A and then closes and reopens later as type B. The one type pollinates the other type. Some varieties will have type B during the day, allowing immediate cross polination between that tree and the other variety with the type A open at that time. Now, the part where I say research is lacking: As general advice in farming circles, people currently tend to use a B type cross pollinator (a second cultivar in about 1/20 trees) for a A type tree. However, there are cases of monocultivar orchards with very high yields that don't have the cross pollinators. So, if the tree opens at night as type B, it means there is something that is active at night that pollinates the trees (I'll give you a hint, bees sleep at night)... I've tried to summarise something that is a bit more complicated, so I hope it makes sense. Another thing you'll point out is that the insect that's active at night would also need to be active during the day if it's pollinating with pollen from earlier the same day. Otherwise you'll still need some access to a type A flower at night. In any case, my main point is that studying the night phase of the flowers is something that I don't know a lot of farmers are doing. For example, it's common to use bee hives for better pollination, and that presupposes that the farmer is not particularly aiming for night time pollination.