Wild bee species of the avocado mosaic of Michoacan, Mexico: Taxonomic and ecomorphological traits

<p>The avocado environmental mosaic of Michoacán primarily spans the mountainous region of the upper basin of the Balsas River, at altitudes between 1400 and 2100 meters. Avocado (&lt;em&gt;Persea americana&lt;/em&gt;) orchards cover approximately 186,813 ha across at least 45 municipalities (where 50% or more of their territory is dedicated to avocado orchards), from the borders with the state of Mexico (in the extreme east) to the borders with the state of Jalisco (in the extreme west)(SIAP 2023). Within this mosaic, avocado orchards alternate with patches of native forests of various ages and degrees of disturbance and other crops such as berries (raspberries, strawberries), traditional maize-agriculture systems (milpa), forestry areas and population centers (SIAP 2023). Notably, the avocado mosaic also encompasses five national protected areas such as the Monarch Butterfly Biosphere Reserve, the Pico de Tancítaro Flora and Fauna Protection Area, and the Barranca del Cupatitzio National Park.</p><p>Mexico is a country of bees! Mexico is home to approximately 2,100 wild bee species, representing 10% of the global richness of these insects (approx. 21,000 spp) (Michener 2000; Sagot et al. 2023). Wild bees, together with the honeybee (&lt;em&gt;Apis mellifera&lt;/em&gt;) and other animal groups (e.g., Bats, Hummingbirds, Butterflies, Beetles) are recognised as pollinating agents for at least 1/3 of our food (Winfree et al. 2007; Ruiz-Toledo et al. 2020). In particular, at least 50 species of wild bees in Mexico have been documented as pollinating agents of high economic importance for their role in the production of chillies, tomatoes, beans, pumpkins, chayotes, oranges, and, of course, avocado (Vergara 2023). However, the richness of wild bees contributing to the pollination of agricultural products in Mexico is a growing field of applied research, so the number of species may be much greater.</p><p>Avocado is, together with agave (&lt;em&gt;Agave tequilana&lt;/em&gt;), an agricultural crop of high economic value for Mexico. However, the unregulated establishment and expansion in certain regions of the avocado belt have been linked to increased deforestation, restricted water access and availability, and increased application of agrochemical inputs for pest and weed control (Denvir et al. 2021, Latorre-Cárdenas et al. 2023). However, we have only just begun to understand the extent, direction, and magnitude of the impact of avocado mosaic establishment on biodiversity. Indeed, despite its economic importance, information on avocado floral visitors is relatively limited. Data on the communities of floral visitors and native pollinators in the Mexican avocado mosaic is much scarcer (and scattered) (Ish-Am et al. 1999; Castañeda-Vildózola et al. 1999; Can-Alonzo et al. 2005; Villamil et al. 2017; Dymond et al. 2021).</p><p>In this sense, we need to increase our efforts to understand how the structure of native pollinating insect communities varies, which can not only visit avocado flowers but also contribute to the persistence of the (non-cultivated) flora associated with the avocado mosaic, and thus to the persistence of the ecosystem services they provide (e.g., pollination, insect pest control, water retention, maintenance of soil structure and nutrient fixation).</p><p>Regarding wild bees, studies have reported at least nine species of Stingless Bees (Tribe: Meliponini) (Ish-Am et al. 1999, Castañeda-Vildózola et al. 1999, Can-Alonzo et al. 2005), three genera of wild bees as floral visitors to avocado (Ish-Am et al. 1999, Castañeda-Vildózola et al. 1999), six genera and three species as avocado pollen carriers (Villamil-Echeverri et al. 2014), and 20 genera and 50 species of wild bees as floral visitors to herbaceous plants associated with the avocado mosaic in Michoacán (Cultid-Medina et al. 2021; AGUHA Project Team 2022). Despite this, a comprehensive list with a high taxonomic resolution of the wild bee species that can be floral visitors and potential effective native pollinators of Michoacán avocado crops (excluding the honeybee, &lt;em&gt;Apis mellifera&lt;/em&gt;) is still lacking.</p><p>The most recent global review of avocado pollinating insects indicates that (Dymond et al. 2021): i) Although Mexico is part of the center of origin of avocado and one of the largest producers worldwide, only five studies have been formally published evaluating any aspect of insect contribution to avocado pollination ecology and ii) concerning bees, the few published studies have focused on &lt;em&gt;Apis mellifera&lt;/em&gt; (a non-native species in the Americas) and at least four species of stingless bees (Tribe Meliponini). Therefore, we do not know the richness and structure of wild bee communities that may be associated with avocado cultivation and its agroecological environment.</p><p>This dataset provides a taxonomic list, ecomorphological traits of valid species, and known distributions of these species on a global scale (at the country level) and in Mexico (at the state level). Importantly, taxonomy and ecomorphological traits are unified with the GBIF dataset “Taxonomic Diversity and Ecomorphological Traits of Wild Bees in Mexico and Mesoamerica” (Sagot et al. 2023).</p>