Winkler Samples, 1999
Winkler samples are an efficient method of sampling leaf litter ants. The method involves sifting bulk samples of leaf litter and rotten wood by agitating them vigorously in a bag above a coarse mesh screen. Litter arthropods are concentrated in the finer "siftate" that passes through the screen. Arthropods are then extracted from the siftate by a passive extraction method, in which the siftate is placed in thin mesh sacks and then suspended and enclosed within an outer cloth "Winkler bag." The Winkler bag tapers to a cup of ethanol. After loading the sample the Winkler bag is closed at the top and suspended in a sheltered location. Arthopods fall from the litter and accumulate in the ethanol, and the sample is taken off after 3 days. Methodological variations involve how the bulk litter is selected. The method used here involved a relatively subjective selection of litter to sift, and was not based on a particular area or volume of bulk litter (thus they are not directly comparable to the Fisher MiniWinkler method). The person taking the sample moved through the habitat selecting pockets of moist litter. These accumulations of litter and rotten wood occurred between buttresses, along the sides of rotten logs, around dead stumps, and in soil depressions. When approximately 6l of siftate were obtained, the material was placed in a cloth bag and returned to the lab.
Twenty samples were taken by the ALAS staff in June and July 1999, and 8 were taken by the ALAS staff in December 1999. The 20 samples from June and July 1999 were taken in the same localities as previous Berlese samples.
The data fields, in order, are:
Collection code: a unique code for a collection. The "W" indicates it is a Winkler sample, the following two numbers are the location, and the final two-digit number is a sample number, in a series from 01 to 28.
Collector: person taking the sample in the field.
Collection date: day the sample was collected from the field, in format day-month-year.
Site: usually a La Selva locality using the trail abbreviations and the number of meters along the trail.
X and Y coordinates: La Selva GIS coordinates.
W/01/009 D. Brenes 18-Jun-99 Parc. sucesionales 1034 1880
W/02/010 R. Vargas C. 21-Jun-99 SSE 1236 1910
W/03/011 R. Vargas C. 21-Jun-99 SHO 650 m. 1498 1848
W/04/012 D. Brenes 21-Jun-99 CCL 842 1444
W/05/018 R. Vargas C. 4-Jul-99 CCL 1261 1075
W/06/017 R. Vargas C. 4-Jul-99 CC 2648 1384
W/07/014 D. Brenes 25-Jun-99 SS0 1465 491
W/08/019 R. Vargas C. 13-Jul-99 SSO 2039 324
W/09/003 R. Vargas C. 14-Jun-99 LOC 1507 -126
W/10/005 D. Brenes 18-Jun-99 CES 671 114
W/11/006 R. Vargas C. 18-Jun-99 SCH 448 -208
W/12/007 R. Vargas C. 18-Jun-99 CEN 398 72
W/13/008 D. Brenes 18-Jun-99 SAT 1020 -85
W/14/013 D. Brenes 25-Jun-99 SSA 2292 -1120
W/15/015 R. Vargas C. 25-Jun-99 SSA 3800 -750
W/16/016 R. Vargas C. 25-Jun-99 SSA 3960 -701
W/17/020 ALAS 13-Jul-99 SSO 1600 550
W/18/004 Brenes/Vargas 14-Jun-99 LOC 1500 -50
W/19/002 Oconitrillo/Paniagua 14-Jun-99 LOC 1400 -100
W/20/001 J. Longino 14-Jun-99 LOC 1300 -50
W/21/021 R. Vargas C. 2-Nov-99 Sendero Ribere–o 3100 2400
W/22/022 R. Vargas C. 2-Nov-99 LEP 3300 -2150
W/23/023 R. Vargas C. 10-Nov-99 Sendero Holdrige 2200 2000
W/24/024 R. Vargas C. 10-Nov-99 Sendero Hartshorn 1600 1050
w/25/025 R. Vargas C. 15-Nov-99 Lindero Peje 1800 -1650
W/26/026 R. Vargas C. 15-Nov-99 Sendero Tres R’os 1600 -800
W/27/027 R. Vargas C. 23-Nov-99 Sendero Jaguar 2600 -250
W/28/028 R. Vargas C. 23-Nov-99 Lindero Sur 3400 850