Three areas of the 62.7 hectare University of Georgia Costa Rica campus were sampled: Forest A (trap locations F1-F5), Forest B (F6-F10) and the open area through the developed part of campus (O1-O10) (Table 1). At each forest trap location, one trap was placed in the understorey and the canopy, so that Forests A and B each contained 10 traps. Sampling occurred for five consecutive days each month January-October 2019. As summarised in Table 2 and detailed below, Forest A was sampled January-October, Forest B was sampled in April and October and the open area was sampled in June-October.

Male Euglossine bees are attracted to baited traps using artificial compounds that mimic those of desired orchids, a method employed regularly by researchers (Sandino 2004, Velez and Pulido-Barrios 2005, Hedström et al. 2006). Cineole is used in this study as it is considered a universal attractant for male orchid bees (Buchmann 2019). Traps used to sample bees were made using a 3.5 l container with lid, with an opening of 4 cm located on one side of the container. A single metal screw hook was attached to the top of the container lid and used to secure the trap. On the inside of the lid, a galvanised wire was used to secure a cotton ball wrapped in wire mesh which served as the attractant site for the cineole.

The dry season is typically marked by high wind speeds and little rainfall. Dry season sampling occurred January to May 2019. During this time, the five sites and ten traps in Forest A were sampled each month, with Forest B being sampled during the peak dry season in April.

The wet season sampling took place June to October 2019. In addition to the ten traps in Forest A, ten trap sites in the open area were added during the wet season. In October, the peak of wet season, Forest B was added, for a total of 30 operational traps. The Forest B site was sampled during the historical peak dry and wet seasons to provide additional data for comparison. We selected trapping sites where the elevation range along a transect was no more than 100 m.

At each of the habitat types, traps were established along a transect, with each sub-unit being 100 m apart (Fig. 1). In the two forested transects, five sub-units were equipped with a canopy and understorey trap. Understorey traps were installed at a height of 1.5 m above the ground. In the open area site, ten traps 1.5 m above the ground were established at different sub-units, each 100 m apart. Sampling the canopy in addition to the understorey allowed us to expand the potential biodiversity in our samples, as canopy sampling is rarely included in most Euglossine trapping studies and canopy specialists are potentially under-represented (Sobek et al. 2009, Ulyshen et al. 2010, Urban-Mead et al. 2021).

Individuals collected at each trap were placed in an 9.58 cm x 17.78 cm Whirlpack plastic pouch. The bags were padded with tissue paper to prevent the movement of live bees from damaging themselves or other specimens. Each collection bag was labelled with the name of the sampling site, date collected, name of the individual collecting the sample and the trap number. The bees were returned to the laboratory and placed in the freezer for at least 24 hours to ensure that all of the specimens were dead before identification. Specimens were mounted or preserved according to standard protocols as follows:

1. The bags were removed from the freezer and each specimen placed in a jar containing 70% ethanol. This is done do remove any residue from the baiting compound or other compounds collected by males from the mid-tibial tuft which could interfere with identification.
2. The bees were removed from the ethanol and placed on a sheet of tissue paper to dry and were identified while still flexible.
3. The bees were mounted, taking into consideration the visibility of the most important diagnostic features of their anatomy. Fig. 2 is an example of a mounted orchid bee. Note that the mid-legs are positioned to ensure that the middle tibia and velvet area are clearly visible and that the forelegs and antenna do not obscure the mandibles or ivory bands, respectively.
4. Mounted specimens were dried at approximately 65⁰C for at least seven days before being placed in long term storage cabinets. This drying period prevents moisture build-up and subsequent moulding of stored specimens.
5. A minimum of 50 individuals per species were mounted and the remaining specimens were preserved in ethanol.

Standard procedures were followed during specimen sorting and identification in the laboratory. All Euglossine specimens were identified to species level using physical characteristics as described in Roubik and Hanson’s dichotomous key in "Orchid bees of tropical America Biology and Field Guide" (Roubik and Hanson 2004). Each specimen was labelled and assigned with a unique specimen code consistent with the collection database. All specimens are deposited in the reference collection at the CIEE campus.

The resulting specimen collection will be used to provide information for future research and as an education tool. Pollinaria attached to bees at the time of collection were preserved on the specimens for future identification. Specimens of non-target taxa were mounted or preserved in ethanol for future identification.

The study was conducted at the Council on International Educational Exchange (CIEE) Monteverde in Puntarenas Province, San Luis, Monteverde, Costa Rica, formerly known as University of Georgia Costa Rica. This site is positioned on the Pacific slope of the Tilarán Mountain Range and borders two nature preserves. The 62.7 ha campus (centred at 10.2827°N, 84.7985°W) consists of three distinct habitat types: 1) secondary premontane wet forest with 60 years of growth (elevation 1,100-1,170 m); 2) open low-intensity agricultural areas; and 3) areas considered highly modified with roads, multi-use recreation areas and buildings/structures within a 40 m elevation range (Fig. 1). Fifty ha are secondary forest and the remaining 12 ha consist of open pasture or facilities. This area exhibits weather patterns consistent with a Central American premontane wet forest, with the driest months being January-April and the wettest months being May-October. Peak dry season is April, corresponding to the highest average temperatures. October is the month with the most rainfall and the lowest average temperatures (World Weather & Climate Information 2019). The average annual temperatures range between 15.6 and 29.4⁰C. The Monteverde region in Costa Rica is largely covered by montane forest, also classified as cloud forest. The area sampled in this study is premontane wet forest, which has elevation of (1,100-1,500 m) and receives an average of 2.4 m of rainfall annually. Premontane wet forest is slightly lower in elevation than cloud forest.

10.279°N and 10.285°N Latitude; -84.795°W and -84.807°W Longitude.

Tribe Euglossini (Arthropoda: Insecta: Hymenoptera: Apidae: Corbiculata)

Physical descriptions and baseline distribution and elevation data were based on Roubik and Hanson's "Orchid bees of tropical America Biology and Field Guide" (Roubik and Hanson 2004) and cross-referenced with GBIF databases to check for any updates (GBIF.org 2021a, GBIF.org 2021b, GBIF.org 2021c, GBIF.org 2021d, GBIF.org 2021f, GBIF.org 2021g, GBIF.org 2021h, GBIF.org 2021i). Table 3 includes catch numbers of each species. The dataset includes 36 species across four genera of Euglossini (Eufriesea, Euglossa, Eulaema and Exaerete) and includes new records for the Monteverde region and expanded elevation range of the following taxa:

GBIF.org 2021a Fuentes 1993

Eufriesea mussitans (Fabricius, 1787)

Identification. Body 17-21 mm long. The clypeus has two strong sublateral ridges and a medial ridge. The medial ridge distinguishes E. mussitans from E. concava, the latter of which exhibits a concave area between the sublateral ridges.

Remarks. This species has been documented from “Mexico to south-eastern Brazil; lowlands up to 1,000 m” (Roubik and Hanson 2004). In Costa Rica, E. mussitans has been documented in the northern Provinces of Guanacaste and Alajuela (GBIF.org 2021b). This is the first known record of E. mussitans in the Puntarenas Province and at the elevation of 1,041-1,168 m. This study documented 1,025 E. mussitans individuals.

Eufriesea rufocauda (Kimsey, 1977)

Identification. Body ~ 14 mm long. Clypeus does not possess sublateral ridges. Face bronze below and green above in males. The anterior part of tergum II is dark and the posterior part of tergum II is reddish-copper with yellow hairs. In lateral view, male labrum has a square outline; when viewed dorsally, a pair of prominent conical points is visible. Differs from E. chrysopyga as: 1) E. chrysopyga has a uniformly purple tergum II; and 2) lateral view of male labrum of E. chrysopyga has a triangular outline and dorsal view reveals barely visible pair of conical points.

Remarks: In Costa Rica, E. rufocauda has been previously documented in Limon, Alajuela, Heredia and Guanacaste (North and in provinces on the Caribbean side) (GBIF.org 2021c). This study provides occurrence data for E. rufocauda in the Monteverde region of the Puntarenas Province and at the elevation range of 1,092-1,154 m. Four E. rufocauda individuals were documented.

Euglossa dodsoni (Moure, 1965)

Identification. Body 10 mm long and reddish-bronze. Green clypeus and complete ivory eye bands. Basal tuft on the middle tibia is inconspicuous, thus appearing to have just one tuft. This distinguishes it clearly from very similar E. erythrochlora (not documented in this study), which has two apparent tibial tufts.

Remarks. This species has been documented from “Costa Rica to Columbia; lowlands up to at least 800 m” (Roubik and Hanson 2004). Euglossa dodsoni has been documented in all provinces of Costa Rica, though only in the southern half of the Puntarenas Province (Monteverde is in the northern part of the Province, bordering Alajuela) (GBIF.org 2021d). This study provides expanded occurrence data for E. dodsoni in the Monteverde region and at the elevation of 1,041-1,168 m. Fifteen E. dodsoni individuals were documented.

Euglossa dressleri (Moure, 1968)

Identification. Body 12 mm long and light green. Mesosoma is sometimes bronzish. Tongue is much shorter than the body. Clypeus is blue and the labrum has two distinct black spots. Ivory eye bands are absent. Two tufts are present and spaced well apart on the middle tibia, with distal tuft barely notched.

Remarks. In Costa Rica, E. dressleri has been documented in San Vito in Puntarenas and Peñas Blancas in Alajuela (GBIF.org 2021e). This study expands the known distribution of E. dressleri to include Monteverde and at an elevation of 1,157 m. One E. dressleri individual was documented.

Euglossa hansoni (Moure, 1965)

Identification. Body 10 mm long and reddish-bronze or green. Thorax is shiny with shallow and reduced punctures. Tongue approximately the length of the body. Top of the head is predominantly green, sometimes with bronze. Ivory eye bands are complete and clypeus is blue. Middle tibia appears to have three tufts. Similar to E. alleni (not documented in this study) and E. purpurea, though E. alenni is very rare with less punctuation on tergum II and E. purpurea is more reddish with blackish clypeus.

Remarks. In Costa Rica, E. hansoni has been documented in Heredia, Limon and southern Puntarenas in the Osa Peninsula and the coastal nature preserve Refugio National de Fauna Silvestre Golfrio (GBIF.org 2021f). This study provides expanded occurrence data for E. hansoni at 1,095-1,157 m and in the region of Monteverde. Seven E. hansoni individuals were documented.

Euglossa ignita (Smith, 1874)

Identification. Body is 14-15 mm long with a green mesosoma and reddish-bronze metasoma. Tongue is longer than the body. Ivory bands are complete and clypeus is green. Broad longitudinal depression present in the middle of the scutellum. Two tufts on the middle tibia are touching, possibly appearing to be one tuft. Distal tuft is larger. A pair of widely separated diagonal slits is present on scutellum II, each with a dense row of setae.

Remarks. Euglossa ignita has been documented in all seven provinces in Costa Rica: Guanacaste, Alajuela, Heredia, Cartago, Limon and southern Puntarenas on the Osa Peninsula (GBIF.org 2021g). This study documents occurrences of E. ignita in the Monteverde region and at an elevation of 1,083-1,137 m. Five E. ignita individuals were documented.

Euglossa tridentata (Moure, 1970)

Identification. Body is green and 11-12 mm long; tongue is much shorter than the body. Ivory eye bands are complete and clypeus is green. Three teeth on mandibles. Middle tibia has two tufts with distal tuft having a shallow notch. Similar to E. deceptrix and E. variabilis, though E. deceptrix and E. variabilis both have two teeth on the mandibles.

Remarks. In Costa Rica, E. tridentata has been recorded in Guanacaste, Alajuela, Heredia, Limon, San Jose and Puntarenas, outside of the Monteverde region (GBIF.org 2021h). This study provides expanded occurrence data for E. tridentata at 1,041-1,168 m and in the Monteverde region. Seventy-four E. tridentata individuals were documented.

Euglossa turbinifex (Dressler, 1978)

Identification. Body is 11 mm long and mostly green with a bluish-green mesosoma. Tongue is the length of the body. Mandibles have two teeth. Two tufts on the middle tibia, basal tuft larger than distal one. Sternum II has a pair of small semicircular depressions containing rows of setae. Similar to E. bursigera, but E. bursigera often has a more bronzish body and has three teeth on the mandible.

Remarks. In Costa Rica, E. turbinifex has been recorded in Alajuela, Heredia and Limon. In the GBIF database, less than 40 specimens are documented in total, 20 of them from Costa Rica (GBIF.org 2021i). This study documents one occurrence of E. turbinifex in the Monteverde region of the Puntarenas Province at an elevation of 1,154 m. One E. turbinifex individual was documented.

Euglossine bee catches of Monteverde, Costa Rica 2019

https://scan-bugs.org/portal/collections/misc/collprofiles.php?collid=299

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