Marked Differences in Butterfly Assemblage Composition between Forest Types in Central Amazonia, Brazil

Round 1

Reviewer 1 Report

I have a permanent study site in California which lies on both sides of a levee demarcating a floodplain. In wet years the floodplain half is under up to 6m of water for several weeks to as long as 5 months. In dry years it may not be flooded at all. Our data monitoring butterfly faunas go back to 1988. We find that in flood years the butterfly fauna feeding on herbaceous hosts is typically eradicated, while the tree-feeders are unharmed. Following withdrawal of the flood waters the floodplain is rapidly recolonized from the upland side and typically experiences a very rapid butterfly "explosion" in the absence of the largely-eradicated parasitoid and predator fauna (most of the species are multivoltine). I give you this information because it raises the question of how the butterfly faunas of the varzea and igapo survive the flooded periods. Are they mostly tree feeders? Do they have to recolonize on a yearly basis? Based on our experience, this is a very relevant question that should be discussed in your paper.

Author Response

Thank you very much for sharing the findings of your work. Contrary to your study site, the flooded forests in Purus region are flooded every year imposing/selecting adaptations to this environment. We are at the moment exploring our data to try to understand all these questions. So far, we have evidence that most species occurred in both seasons, but the abundance of individuals decreased by more than half in the high-water season compared to the low-water season. There was also species turnover between seasons, with the arrival of new species (which was not sampled in low-water season) in flooded forests during the flood (especially in várzea) and the disappearance of other ones. We think that only a few individuals can survive in the high-water season. The high-water season is the fructification time at várzea and this could be an explanation to species arrival and survival (for the fruit-feeding). Then, when the water recedes, there is an increase in the population density, especially the grass feeders, which are the most abundant group in our study (Satyrinae butterflies). We are now evaluating the time of generation of each species and its host plant to get an idea of species life cycle and seasonality. Given the complexity of this question, we decided to prepare another manuscript devoted specifically to evaluating butterfly community between seasons, vertical displacement with the flood, horizontal displacement based on composition, water depth influence, etc.

Reviewer 2 Report

This is a simple, but generally well executed study that investigates differences in butterfly richness and composition between the three main forest types present in Amazonia, terra firme, varzea and igapo. Results generally are congruent with findings from previous studies on other faunal groups. Although thus not particularly novel, the study still makes a valuable contribution to the literature. The paper is for the most part well written and structured, the methods are sound and the results are well presented. I liked the focus of the discussion which does a good job at putting the results into a broader context. Study limitations should, however, be more overtly discussed in this section. I have no major concerns about the paper, but have made a number of comments and edits along the PDF of the original submission for the authors' perusal. 

 

Comments for author File: Comments.pdf

Author Response

Authors: Thank you very much for your comments. We have expanded the limitations of our study in the discussion section. Our answers to your questions and comments in the PDF are below:

Reviewer 2: I would add a bit more detail here, saying that várzea and igapó refer to whitewater-indundated forests and blackwater-inundated forests, respectively.

Authors: Done

Reviewer 2: please rephrase “its role in the environment balance in the species occurrence”.

Authors: We have changed the text accordingly.

Reviewer 2: At what height were traps installed in the canopy?

Reviewer 2: So how often were individual transects walked?

Authors: When we checked the traps every 48 hours and did the pollard walk on along the transects simultaneously. This is now clarified in the text (line 136).

Reviewer 2: I suggest you add the accession numbers for the deposited specimens

Authors: We do not yet have the numbers for the deposited specimens.

Reviewer 2: So you also pooled data for both strata, canopy and understory?

Authors: Yes, we have changed the text accordingly

Reviewer 2: Missing from the plot, please add

Authors: The figures have now been formatted so that they can be viewed correctly.

Reviewer 2: The circles delineating the different sets are missing

Authors: The figures have now been formatted so that they can be viewed correctly.

Reviewer 2: Presumably there are 6 points here for each habitat since you probably considered low-water and high-water season separately? If so, please make this clearer here in the legend and in the text (Methods).

Authors: Thank you for bringing this to our attention. We explain this in the methods (line 154): “The sample unit for all analyses is therefore transect in each season”.

Reviewer 2: correct the citation format here and for the subsequent citations

Authors: Done.

Reviewer 2: “provides more ammunition for”

Authors: We have changed the text accordingly.

Reviewer 3 Report

This is a most valuable contribution to our knowledge of Amazonian entomology. As stated in your paper (l 271 "Despite the butterfly fauna in the Brazilian Amazonia having been studied for almost 271two centuries [83-85], there is a relatively small number of community ecology studies in 272central Amazonia that use butterflies as model organisms " - this is indeed amazing! Therefore this study is timely and relevant. I did not detect inconsistencies or flaws, except the Venn diagram which was not displayed properly in my pdf version - my only suggestion is to share these important data via biodiversity data portals connected to gbif (www.gbif.org), but this is just a suggestion, eventually for a forth-coming, extended data paper.

Author Response

Thank you for your comments. We appreciate that you enjoyed the reading. Sorry about the Venn diagram, we have changed the format of the figures to ensure correct viewing. We chose to share our table with all butterflies captures, forest type, sampling method and stratification so that other people can use this data for future work. Thank you for suggesting GBIF as an additional data sharing platform.