The food web in water systems relies on aquatic insects. These insects also indicate changes in the environment because they help break down organic materials, making nutrients more available. This research was conducted in Panama, in the Marica River, located in Las Delicias, which is a community in Penonome district, Coclé province. From February to July 2022, we conducted six field excursions to establish five stations and collect two samples of fallen leaves at each station once a month to identify the variety of aquatic insects connected with the leaf packs. At each site, measurements of the physical parameters, such as pH, current speed, and water column depth, were also made. The ShannonWiener, Margalef, and Simpson indices were employed to measure variety. Four thousand one hundred eighty-five (4185) specimens were collected, representing 9 orders, 30 families, 3 subfamilies, and 35 genera. The Diptera order is the most abundant (2078), followed by Ephemeroptera (1111) and Trichoptera (450). Among the most numerous subfamilies are: Chironominae (1615), Tanypodinae (293), and Orthocladinae (104). The most abundant genera were: Caenis (491), Chimarra (271), Thraulodes (255), and Farrodes (203). The month of July presented greater richness and dominance. Regarding the physical factors such as the speed of the current, it was observed that at a lower speed, there is a greater number of insects. Considering the depth of the river, at a shallower depth, there is a greater abundance of organisms. The average pH in the sampling stations was between 7.3 and 7.5. The value of pH 7 indicates that the river is optimal for harboring insects. We concluded that the Marica River has a high diversity and abundance of aquatic insects.
