Discovery of Megachile ( Pseudomegachile ) lanata ( Fabricius , 1775 ) ( Hymenoptera , Megachilidae ) in Colombia , an adventive bee species from the Old World

We record for the first time for Colombia Megachile (Pseudomegachile) lanata (Fabricius, 1775), a bee species from Southeast Asia. This is the first record of an adventive bee species for the country besides Apis mellifera Linnaeus, 1758, the European honey bee. Megachile lanata appears to have arrived to the Caribbean coast of Colombia nearly half a century ago, reaching the Orinoquia region recently. We provide comments on diagnostic features to facilitate the recognition of this bee species and discuss its possible establishment in Colombia.


Introduction
A few bee species, such as the European honey bee (Apis mellifera Linnaeus, 1758), have been introduced deliberately to many areas of the world for their products and services.However, the introduction of the majority of non-native bee species have been accidental and due to human activity (e.g., Cane 2003, Goulson 2003, Russo 2016).A recent review on this topic (Russo 2016) indicated that about 80 bee species (30 genera of 7 families) worldwide are non-native, which represents a small percentage (0.004%) of the global bee fauna.The invasive range of non-native bees varies in extension from an island (e.g., Anthidium vigintiduopunctatum Friese, 1904 in the Galápagos Archipelago) to nearly cosmopolitan in distribution, as in the case of the European honey bees and the wool carder bee Anthidium manicatum (Linnaeus, 1758) (e.g., Gonzalez et al. 2010, Strange et al. 2011).The majority of non-native bees belong to the families Megachilidae and Apidae, primarily in the genus Megachile Latreille, 1802.Most non-native bees are polylectic and nest in stems, twigs, and existing cavities, which facilitate their dispersion and adaptation to new environments when compared to olygolectic and ground-nesting bees (Cane 2003, Russo 2016).
Non-native species are often one of the biggest threats to the local biodiversity, although they can have positive impacts on the new environment.In the case of bees, non-native species might compete with the native fauna for floral resources or nesting sites, transmit pathogens or parasites, affect the pollination of native plants, disrupt pollination networks, or pollinate invasive plant species (Goulson 2003, Barthell et al. 2001, Hall and Avila 2016, Mallinger et al. 2017).They might also pollinate non-native crops and become economically important, as in the case of Megachile rotundata (Fabricius, 1787), a solitary bee introduced to many parts of the world as a pollinator of alfalfa (Pitts-Singer and Cane 2011).
Given the potential impacts of non-native species on the local biodiversity, the discovery of a new bee for the Colombian fauna is therefore of considerable interest.Herein, we report for the first time Megachile (Pseudomegachile) lanata (Fabricius, 1775), a species native to India (Pasteels 1965) and adventive to many regions of both hemispheres.In the Eastern Hemisphere, it occurs in Mauritius, Madagascar, the Hawaiian Islands, French Polynesia, and Thailand.In the Western Hemisphere, Mitchell (1962) suggested that M. lanata arrived through the West Indies during the slave-trade period in the 1700-1800s.Today, this species occurs in southern Florida, USA, Cuba, Jamaica, Puerto Rico, Saint Vincent and Grenadines, French West Indies, Trinidad and Tobago, Bolivia, Guyana, and French Guyana (Moure 1953, Genaro 1996, Pauly et al. 2001, Moure et al. 2007, Raw 2007, Meurgey 2016, Ascher and Pickering 2018).Thus, our records from Colombia extend the invasive range of this species in South America.We discuss the likely establishment of this species in Colombia and, to facilitate its recognition, provide comparative comments on diagnostic features.

Methods
The specimens discussed herein are deposited in the Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia (ICN) and Laboratorio de Investigaciones en Abejas, Universidad Nacional de Colombia, Bogotá, Colombia (LABUN).Although we did not find additional specimens of M. lanata, we also searched the insect collections at the Museo Entomológico, Facultad de Agronomía, Universidad Nacional de Colombia, Bogotá, and Museo Javeriano de Historia Natural Lorezo Uribe, S.J., Universidad Javeriana, Bogotá.We took photomicrographs with a Leica MC 170HD camera attached to a Leica M205A stereomicroscope.To map the distribution of the species, we used Google Earth (Google, Mountain View, CA, USA) to acquire the coordinates from the localities recorded in the specimen labels.We generated a map using SimpleMappr (Shorthouse 2010).We reproduced label data as appearing on the labels attached to the same specimen.We separated information on different labels by a single slash (/) and indicated annotations to clarify information in square brackets.

Results
Genus Megachile Latreille, 1802 Subgenus Pseudomegachile Friese, 1898 Megachile (Pseudomegachile) lanata (Fabricius, 1775) Figure 1 Diagnosis.Specimens of M. lanata can be reliably identified to M. (Pseudomegachile) using Michener's (2007) keys to the subgenera of Megachile.Both sexes of M. lanata differ from M. (Pseudomegachile) ericetorum Lepeletier, 1841, the only other species of M. (Pseudomegachile) adventive to the New World (Sheffield et al. 2010), as well as from any other megachilid bee from Colombia, by the body pubescence.In M. lanata, the pubescence of the head, mesosoma, and first 2 terga is orange, and thus it contrasts with the remaining black terga.In addition, the third to fifth terga have white apical bands of setae and the female metasomal scopa is white (Fig. 1B).Although M. lanata and M. ericetorum are about the same size (12-16 mm in body length), the only record of the latter species is from Canada and its body pubescence is whitish to yellowish, including the female metasomal scopa.In addition, the male preapical carina of the sixth tergum is denticulate in M. ericetorum whereas in M. lanata is nearly entire, sometimes ondulate and medially emarginate.Because of the lack of interdental laminae (cutting edges sensu Michener 2007) between the mandibular teeth of the female mandible, M. lanata can be confused with species of M. (Chrysosarus) Mitchell.However, no species of this subgenus possess a body coloration similar to that of M. lanata.

Discussion
This is the first record of an adventive bee species for Colombia besides the European honey bee.We do not know how and when exactly M. lanata arrived into the country.However, our records indicate that M. lanata has been undetected in Colombia for nearly half a century, which is not surprising given that the melittofauna of the country is still in its early stages of exploration.In addition, most taxonomic work in Colombia has been focused on corbiculate bees (Gonzalez 2014).Given the wide distribution of M. lanata on the Caribbean islands and earlier records from the Departments of Magdalena and La Guajira, both on the Caribbean coast, it is likely that it arrived from any of these islands.
Adventive species may fail to become established if suitable habitats or adequate resources are not available.This appears not to be the case for M. lanata in Colombia, as the most recent record is from 2015.However, field collections by the senior author did not detect this species near Santa Marta (Magdalena) in December of 2011 nor in Riohacha and nearby areas in La Guajira during December of 2016.This suggests either that Colombian populations of M. lanata are sparse or that this species is highly seasonal, as specimens from the Caribbean coast were collected in April and May.However, the latter is unlikely because in the West Indies and Cuba both sexes are active throughout the year (Genaro 1996), and the latest record in Colombia is from September.
The records of M. lanata in Colombia are from 2 natural regions (Fig. 1A), each characterized by a different type of vegetation.Dry tropical forests are predominant in the Caribbean region whereas tropical grasslands and savannas dominate the Orinoquia region.We do not know if the presence of M. lanata on each natural region represents an independent event of colonization or if the most recent record from Puerto Lopez (Orinoquia region) is a range expansion from its likely initial introduction in the Caribbean coast.Although either scenario is equally plausible, it shows the potential of this species to colonize different ecosystems in Colombia.
Neither positive nor negative impacts have yet been recorded for M. lanata in its invasive range (Russo 2016), and thus the potential impact of this species on the Colombian biodiversity remains to be investigated.Future studies in Colombia should monitor the establishment and spread of this species, as well as record its floral hosts, as many non-native bees tend to share floral resources with native bees (Matteson et al. 2008).We hope this work encourages further research measuring direct, long-term, and population-level effects of this bee to understand its potential impact on the Colombian melittofauna.