Nocturnal Bees as Crop Pollinators

Round 1

Reviewer 1 Report

There are reasonable guesses that many bees in tropical forests specialize on the leftovers from nocturnal flowers visited by large animals. These are the predominant day-foraging honeybees and stingless bees. Then, especially in the Old World, there are bees that do the reverse by specializing on diurnal flowers that still offer food at sunset and night. The nocturnal bees, the crepuscular and the matinal bees each share part of both these strategies. Their efficacy and fitness is what needs to be explained within the context of fluctuating, or now, disappearing, resource environments. This habitat is where all agriculture with any pretense of ‘sustainability’ must take hold.

The authors show that much is still unknown about the actual plant species used or pollinated by Megalopta and other less nocturnal bees, but the same could be said of practically all tropical bees. Any flower that is diurnal, I would maintain, is going to lack pollen after a short time and may continue to yield nectar into the twilight or night. I can only presume that diurnal Solanaceae, Melastomataceae and many legumes have no nectar at any time and will thus not likely provide nocturnal bees with any substantial food reward. Some very early morning flowers like Passiflora or guaraná might get visited first by matinal bees, but then the ‘normal’ diurnal bees take over. The plant species that the authors list almost all have diurnal anthesis. An exceptional flower like the Parkia studied by Houston might rely chiefly on Megalopta, but otherwise, species of this genus are first visited by Apis (now A. mellifera scutellata and its descendants), at dusk, and then by bats. Moreover, a 7-year study of Megalopta revealed, on Barro Colorado Island, that their abundance was consistently lowest during dry season, which is when many crops are produced. Why should we  look, therefore, to nocturnal, crepuscular or matinal bees for crop pollination?

The authors maintain that the nocturnal bees may be more specialized than diurnal species in flower use, but this is the opposite of the conclusion by Somanathan et al. (2020) who found at least a few pollen types on bees, and sometimes pollen of more than one species in one trip. Thus, even less is clear than the present authors suggest. They conclude with some research priority suggestions, which I found less than comprehensive. If the public is already skeptical about the need of saving habitat for pollinators that are not in some way managed, how will they believe that a few ‘opportunist’ nocturnal bees really are so important to encourage maintaining ‘brush’ and other fire tinder, in place of clean crop fields? And since the nocturnal etc. bees all are solitary, how can they compete with the more familiar honeybees and stingless bees as mainstays of crop pollination? 

Author Response

We attached the responses to the reviewer’s comments

Author Response File: Author Response.pdf

Reviewer 2 Report

I reviewed, "Nocturnal bees as crop pollinators" by Cordeiro et al. Overall I think this article may be of interest to a reader of Agronomy.

A few comments:

Line 35:....., such as cambuci

Line 37-39: Revise sentence-doesn't make sense

Line 83-what traits are you referring to?

Line 159-162: the other individuals, are these livig in a different area or also in guarana fields? This sentence doesn't make sense

Line 256-The grammer suddenly switches to a personal note. First person. I'd remove personal realizations etc. Same for line 259 

Author Response

We attached the responses to the reviewer’s comments

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Reading this was quite enjoyable. Now, a few English or writing suggestions are as follows:

line   issue

261   determined

266  the visits

268 delete 'mentioned, write also have, delete 'also'

274  Question- Can the list include caution not to burn dead wood- brush, e.g.?