Project ALAS began in late 1991. An existing structure at La Selva Biological Station was remodeled as an entomological laboratory dedicated to the project. Danilo Brenes and Ronald Vargas were chosen from among more than 50 applicants from communities surrounding La Selva to attend the National Biodiversity Institute (INBio) 6-month Parataxonomist course in 1992. (Parataxonomists are rapidly trained biologists who assist INBio in the national inventory process.) Later, Maylin Paniagua and Nelci Oconotrillo joined the project as Biodiversity Technicians and were trained by visiting taxonomic collaborators.

During succeeding years, ALAS taxonomic collaborators visited La Selva to train the ALAS staff to recognize, prepare, and identify (at least to genus or family level) each survey taxon. Following each period of training, the resident staff collected quantitative arthropod samples following specific protocols, using a variety of techniques: Berlese funnels, Malaise traps, blacklights, canopy fogging, and pitfall traps. They prepared specimens (on pins, in alcohol, or on slides) and entered specimen data in a relational database designed for the project. Through return visits to La Selva and through loans of ALAS material through INBio, ALAS taxonomic collaborators pursue identification and description of the material collected and prepared at La Selva.

From 1992 until 2000 ALAS focused on the fauna of La Selva itself, carried out in three phases: ALAS I, II, and III. Each phase was funded by a separate grant from The National Science Foundation Biotic Surveys and Inventories Program (now Biodiversity Surveys and Inventories). Each phase was a combination of continuity, attempting complete inventories of megadiverse core focal taxa, and innovation, adding new taxa and new methods.

In 2001 we began ALAS IV, a 5-year grant to expand the geographic scope of the project. La Selva Biological Station, at 50m elevation, is at the base of a forested slope that extends to the peak of Volcan Barva, rising to 2600m over a distance of 35 kilometers. This land has protected status, forming the western edge of Braulio Carrillo National Park. A trail, called the Barva transect, extends from La Selva to the peak and has been used for previous explorations of this elevational gradient. ALAS IV carried out a program of quantitative sampling at five different elevations along the transect, with one field site sampled each year. Each year improvements were made to shelters along the transect, greatly improving the transect infrastructure for biological research. Two-week field expeditions were carried out in February, March, and April of each year. Samples were returned to the ALAS lab for subsequent processing during the rest of the year.

There were changes in staff and facilities during ALAS IV. Early in ALAS IV we were dismayed that Nelci Oconitrillo, a highly capable parataxonomist, had to leave the project to care for a family member. However, we were fortunate to find a replacement, Flor Cascante, who with training from project staff and visiting collaborators quickly brought the technical capacity of the ALAS team back up to full force. Also during this time OTS was successful at obtaining a facilities improvement grant, part of which funded the construction of a spacious new laboratory dedicated to Project ALAS.

As of August 2005 we have completed the fifth year of ALAS IV field sampling and are processing the final year's samples. A renewal proposal is pending for ALAS V, to continue this monumental inventory effort.