2025 Field Report: Flying Insect Survey (PDF)
Date: July 13 – 17, 2025
Location: Explorama’s Napo-Sucusari Biological Reserve, Loreto Peru
Study Site: The Amazon Conservatory for Tropical Studies (ACTS). Forest floor.
Lead Researcher: Carissa Ganong, PhD
Team Members: Janet L. Ort*, Julie Taylor Rivenbark*, Emily Sweet, Orthon Ricardo Vargas-Cardoso*, Percy Reyna Inuma (* = author of this report)
What happens when you look for biodiversity on both the forest floor and in the rainforest canopy? During the Amazon Research Initiative for Educators (ARIE), educators and researchers used simple fruit-baited traps at the Amazon Conservatory of Tropical Studies (ACTS) in Peru to explore how butterflies, moths, and other flying insects are distributed between the canopy and the forest understory. The results showed that flying insect abundance was significantly higher near the forest floor, highlighting the importance of understory habitats. This field study shows how curiosity-driven, accessible research can reveal hidden patterns in biodiversity while connecting authentic science in the Amazon to classrooms far beyond it.
Abstract
We examined vertical differences in Lepidoptera and flying insect communities in a lowland Amazon rainforest using fruit-baited traps at the Amazon Conservatory of Tropical Studies (ACTS) in Loreto, Peru. Eight Van Someren-Rydon traps were deployed in understory and canopy habitats over five days in July 2025. Insect abundance, order richness, and diversity were compared between strata using chi-square tests and the Shannon diversity index. Lepidoptera and overall insect abundance were significantly higher in the understory than in the canopy (p < 0.0001), contrary to predictions. Order richness did not differ significantly between habitats, though Shannon diversity was greater in the understory (H = 1.41) than the canopy (H = 1.25). These results underscore the ecological importance of understory habitats and demonstrate the utility of fruit-baited trapping for scalable biodiversity research and education.
Introduction
Understanding species distributions is a key component of preserving tropical biodiversity. Lowland tropical rainforest – especially the canopy – is an extraordinarily diverse but still understudied ecosystem, and quantifications of species diversity are still lacking. Lepidopterans (butterflies and moths) are a diverse taxon that range throughout rainforest vertical strata, and at least two previous studies (DeVries et al. 1997, Fordyce & DeVries 2016) demonstrated that lepidopteran abundance, richness, and community composition vary between canopy and forest floor sampling sites in Neotropical rainforests. Many lepidopterans are frugivores that are attracted to fruit-baited traps, allowing relatively easy sampling. This type of sampling has not, to our knowledge, previously been conducted in the Loreto region of Peru.
The goal of this project was to compare lepidopteran abundance, richness, and species diversity in baited cone traps on the forest floor and forest canopy walkway. Our prediction was that lepidopteran abundance, richness, and diversity would be higher in the canopy than on the forest floor.
Materials and Methods
This research was conducted at the Amazon Conservatory of Tropical Studies (ACTS) field station on the 4,136-acre Napo-Sucusari Biological Reserve in Loreto Province near Iquitos, Peru. The Napo-Sucusari Reserve includes a 13-platform canopy walkway and borders the 977,000-acre Maijuna-Kichwa Regional Conservation Area.
Fieldwork was conducted July 13-17, 2025. On July 13, we deployed eight Van Someren-Rydon cone traps, four on the forest floor and four on canopy walkway platforms (Figure 1). Forest floor locations were selected haphazardly along the trail to the canopy walkway, and canopy traps were placed at the first four canopy platforms (4, 5, 7, and 8) not frequently occupied by other groups. We baited each trap with half of a mashed banana and a splash of locally sourced sugarcane rum. On the final day of trapping, the half banana was replaced with an orange due to lack of bananas.
We collected specimens every morning July 14-17. Each day we used a handheld Kestrel unit to record air temperature, relative humidity, wind speed, and dewpoint at the first forest floor trap and the first canopy trap; we also recorded weather conditions.
Each insect was captured by hand and placed into either a glassine envelope (for larger lepidopterans) or a plastic centrifuge tube. Insects were returned to the station, chilled in a freezer for 2-10 minutes, and photographed. The photos included the date and location of each and both upper and lower sides of the specimen if possible. Insects were released after monitored recovery (Figure 2).
Photos of all individuals collected during the study were uploaded to iNaturalist. These photos can be found at the following URL or by searching for “Morpho Institute Bug Team 2025” in iNaturalist projects. Further identification for each individual is still ongoing and will be updated in iNaturalist by project contributors and taxonomic experts (Figure 3).
Differences in lepidopteran abundance, overall insect abundance, and insect order richness between the understory and canopy were compared using chi square tests.
Results
Total Lepidoptera abundance was significantly higher in the understory than in the canopy (chi square value= 46.545, df=1, p<0.0001; Figure 4).
In addition, overall insect abundance was significantly higher on the forest floor than the canopy (chi square value= 153.125, df=1, p<0.0001; Figure 5).
The understory traps also consistently had higher richness, but there was no significant difference in insect order richness between canopy and understory habitat (chi square value= 0.692, df=1, p=0.4054; Figure 6).
Finally, the Shannon diversity index (Table 1) shows greater diversity in the understory (H=1.41) than in the canopy (H=1.25). Evenness was higher in the canopy the N is higher in the understory 29 vs 239. These differences impacted the diversity analysis.
Table 1. Shannon diversity index data for the canopy and understory.
Discussion
Overall, the traps on the forest floor experienced significantly higher abundance when quantifying both Lepidopterans and insects as a whole. We were surprised to find that moths far outnumbered butterflies (subfamily Papilionoidea) in the traps. Trap U3 (understory 3) was the most successful in terms of highest abundance, richness, and the largest sizes of Lepidoptera; this could be due to many factors, but most likely due to its proximity to a small stream, providing ample open space and microhabitat for these species (Vu & Quang, 2011).
There are several interrelated ecological factors that could be contributing higher insect abundance in the forest understory: a) more diverse host and nectar plants, b) stable and suitable conditions (Richter et al. 2023), c) greater protection from predators (Loiselle & Farji-Brener 2002), d) environments that support their specific flight and behavioral adaptations, e) there is a greater variety of shrubs, small trees, and herbaceous plants in the understory (Mota et al. 2023, Weerakoon et al. 2015). Therefore, the understory is a very important place for the development and growth of Lepidoptera, where they interact with various types of plants. However, it is important to note that our dataset is relatively small and increasing the number of sites and traps would provide a more representative picture of the ACTS lepidopteran community.
This project was easy to manage and develop. It has potential for a longitudinal study as is; an additional focus could involve changing the bait at the same locations. In addition, further locations could be added as research questions are refined. This project design is also easily translated into classroom applications at any level; the methodology of sampling organisms in different habitats is scalable from Petri dishes to large traps and for any type of school setting.
Next Steps
This project is considered a pilot. A full survey project will be launched during ARIE 2026.
Classroom Connections
Some topics to consider include:
- Varying biotic and abiotic conditions
- Choice of sampling locations
- Experimental design
- Connections to indicator species
Acknowledgements
Many thanks to Brice Brittsan, Becca Brunner, Kirsten Franklin, and Andrew Mezheritskiy for help checking the traps and to the Morpho Institute & ARIE for amazing opportunities in research and professional development as well as their commitment, vision, and support of participants and determination to honor the land, water, traditions and peoples of the Amazon River Watershed.
References
DeVries, P. J., Murray, D., & Lande, R. (1997). Species diversity in vertical, horizontal, and temporal dimensions of a fruit-feeding butterfly community in an Ecuadorian rainforest. Biological Journal of the Linnean Society, 62(3), 343-364.
Fordyce, J. A., & DeVries, P. J. (2016). A tale of two communities: Neotropical butterfly assemblages show higher beta diversity in the canopy compared to the understory. Oecologia, 181(1), 235-243.
Loiselle, Bette A., and Alejandro G. Farji-Brener (2002). What’s up? An experimental comparison of predation levels between canopy and understory in a tropical wet forest. Biotropica 34(2), 327-330.
Mota, L. L., Santos, J. P., Willmott, K. R., & Freitas, A. V. L. (2023). Butterfly assemblages differ among vegetation types in southern Amazonia. Diversity, 15(5), 624. https://doi.org/10.3390/d15050624
Richter, A., de Souza Mendonça, M., Jr., Gawlinski, K., & Iserhard, C. A. (2023). Microclimatic fluctuation throughout the day influences subtropical fruit-feeding butterfly assemblages between the canopy and understory. Diversity, 15(4), 560. https://doi.org/10.3390/d15040560
Vu, L. V., & Quang Vu, C. (2011). Diversity pattern of butterfly communities (Lepidoptera, Papilionoidae) in different habitat types in a tropical rain forest of southern Vietnam. International Scholarly Research Notices, 2011(1), 818545
Weerakoon, B. M. B., Bandara, A. M. R. S., & Ranawana, K. B. (2015). Impact of canopy cover on butterfly abundance and diversity in intermediate zone forest of Sri Lanka. Journal of Tropical Forestry and Environment, 5(1).
For additional information or questions about this field report, please contact Dr. Lindsey Swierk (lindseyns@gmail.com), Director of Scientific Research for The Morpho Institute and Associate Director of Research for the Amazon Conservatory for Tropical Studies.
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