DOI: 10.5061/dryad.1zcrjdg54
title: Data from: Arthropod rain in a lowland tropical forest

description: Resource subsidies link habitats, facilitating the flow of energy across
 ecological boundaries. In lowland tropical forests, "arthropod
 rain" (i.e., arthropods falling from the canopy to the understory)
 represents a potentially important but understudied terrestrial nutrient
 flux. We investigated the composition, biomass, and environmental drivers
 of arthropod rain on Barro Colorado Island, Panama. Pairs of traps–pan
 traps and pole traps–placed 1 m above the ground, respectively collected
 fallen arthropods and arthropods potentially climbing to the canopy.
 Average (± SE) arthropod biomass density in pan traps was dominated by
 Hymenoptera (primarily ants; 0.501 ± 0.023 mg dry mass m-2 day-1) and
 Lepidoptera larvae (0.228 ± 0.001 mg m-2 day-1). Total dry biomass density
 in pan traps was 0.896 ± 0.033 mg m-2 day-1; thus, ca. 27 kg of arthropod
 biomass rains into the understory per km2 per month during the wet season
 in this forest. Arthropod abundance in pan traps declined with increasing
 canopy cover and increased with increasing frequency of high wind events.
 By contrast, arthropod biomass density showed no relationship with canopy
 cover or environmental variables. Arthropod abundance was higher in pole
 traps than in pan traps and was dominated by Collembola and Acari.
 Compositional overlap between pan and pole trap contents suggests that
 some fallen arboreal arthropods regularly return to the canopy. These
 findings illustrate an understudied pathway linking canopy and understory
 food webs within tropical forests, and the complex interactions between
 environmental conditions and arthropod rain.
description: # Data from: Arthropod rain in a lowland tropical forest Dataset DOI:
 [10.5061/dryad.1zcrjdg54](10.5061/dryad.1zcrjdg54) ## Description of the
 data and file structure Data were collected to measure the quantity and
 biomass of arthropods falling from the forest canopy into the understory
 and their relationship to strong wind and rain events in Panama. Note:
 'NA' in any cell = missing data or no data ### Files and
 variables #### File: arth_rain_weather.csv **Description:**  #####
 Variables * reference: voucher specimen code * collection_date: date
 sample was collected as mm/dd/yyy * location: transect site name *
 trap_type: type of trap * trap_number: unique trap numbered position
 within a transect * trap_code: code used to identify individual traps *
 densiometer: percent canopy cover measurement (%) * latitude: latitude
 coordinate of the middle of the transect at a given location (decimal
 degree) * longitude: longitude coordinate of the middle of the transect at
 a given location (decimal degree) * arthropod_type: common name for the
 specimen * class: taxonomic class of the specimen * morphospecies:
 morphospecies code for the specimen * order: taxonomic order of the
 specimen * abundance: number of individuals of a morphospecies found in
 the trap * notes: additional information, including morphospecies
 descriptors * average_wsmx: daily average maximum wind speed (m/s) *
 sum_ra: cumulative daily precipitation (mm) * total_precip_flag: frequency
 of precipitation events above 90% quantile * total_wind_flag: frequency of
 wind speeds above 95% quantile ## Code/software All data files are in CSV
 format and can be opened with R or any text editor. All data were analyzed
 in R using the packages described in the published paper. ## Access
 information Other publicly accessible locations of the data: * NA Data was
 derived from the following sources: * Weather data were obtained from the
 STRI Physical Monitoring public database at this site:
 [https://striresearch.si.edu/physical-monitoring/barro-colorado/](https://striresearch.si.edu/physical-monitoring/barro-colorado/)