State of knowledge of the Tenebrionidae ( Insecta : Coleoptera ) in Colombia based on bibliographic revision

Tenebrionidae is one of the most diverse families in Coleoptera. However, research on the family in Colombia is limited. Based on a comprehensive literature review, a list of tenebrionid species known from the country was compiled and the state of knowledge is analyzed. Based on this information, the Tenebrionidae in Colombia are represented by 326 species, organized into 95 genera (seven subgenera), 30 tribes, and nine subfamilies. Cundinamarca, including Bogotá, presents the highest number of recorded species with 52, followed by Valle del Cauca with sixteen, and Bolívar with thirteen; eight departments have records for only a single species, and ten do not have records of any tenebrionid species. Potential reasons for the historically limited research on Colombian tenebrionids are discussed and actions to reduce these knowledge gaps are proposed.


INTRODUCTION
Darkling beetles (Coleoptera: Tenebrionidae) constitute one of the most diverse families of Coleoptera, both in number of species and diversity of habits (Aalbu et al. 2002, Matthews et al. 2010, Kanda 2017, Bouchard et al. 2021. Most species are closely associated with either soil or vegetation and play important roles in nutrient cycling, especially litter decomposition (Schowalter 2008, Almeida and Mise 2009, Cheli et al. 2022. Many darkling beetle groups, particularly the subfamilies Pimeliinae and Blaptinae, are highly represented in arid and semi-arid environments worldwide; in tropical forests, their fauna is also well-represented but underexplored. On the other hand, the taxonomic knowledge of darkling beetles in humid environments such as tropical forests (mainly subfamilies Diaperinae, Stenochiinae, and Tenebrioninae) is even more scarce. In general, tenebrionids are sensitive to variations in environmental conditions and have been proposed as bioindicators of ecological degradation in Ascuntar-Osnas, et al., 2023. Caldasia 45(3):xx-xx natural and anthropized areas, and in places undergoing restoration processes (Cartagena 2002, Michaels and Michaels 2007, Cárdenas et al. 2011, Cheli et al. 2021. Tenebrionids are typically recognized based on their 5-5-4 tarsal formula (present in most species), five visible abdominal ventrites with the first three being fused, and antennal insertions concealed under expansions of the frons (Aalbu et al. 2002, Matthews et al. 2010, Giraldo and Flores 2016. Currently, there are eleven subfamilies recognized within Tenebrionidae, with 2307 genera and approximately 30 000 species (Matthews et al. 2010, Bouchard et al. 2021). In the Neotropical region, at least 478 genera and 4624 species of darkling beetles are estimated (Blackwelder 1944, Costa 2000, Almeida and Mise 2009. Updated tenebrionid species lists are available for countries in North and Central America, including the Caribbean Islands (Maes and Merkl 1991, Cifuentes-R and Zaragoza-C 2014, Bousquet et al. 2018; in South America, Argentina (Flores 1998, Cabrera et al. 2010), Brazil (Almeida and Mise 2009, Spiessberger et al. 2022), Chile (Vidal-GH and Guerrero-G 2007), French Guiana (MNHN and OFB 2022), and Peru (Smith et al. 2015, Giraldo andFlores 2016) have updated species lists for Tenebrionidae.
Nevertheless, knowledge about the Neotropical fauna of darkling beetles remains incomplete (Johnston et al. 2022), and several neotropical countries, including Colombia, do not have an updated checklist for this beetle family. In particular, the first catalog of Neotropical Coleoptera (Blackwelder 1944) included 286 species of darkling beetles recorded from Colombia, with no information about the distribution of the species within the country. Several phylogenetic studies (e.g., Doyen and Lawrence 1979, Kergoat et al. 2014, Kanda 2017, Cheng et al. 2022) have resulted in different nomenclatural arrangements, proposals, and revisions during the last decade (Bouchard et al. 2005, Bremer and Martin 2014, Bousquet and Bouchard 2017, Bousquet et al. 2018. In addition, scattered information on new species and new records has been published, reporting on material deposited in international collections (Marcuzzi 1954, Doyen 1989, Steiner Jr. 2004, Ferrer et al. 2005, Aloquio and Lopes-A 2015Smith and Sanchez 2015;Kanda 2016, Grey andSmith 2020), rendering Blackwelder's checklist out of date.
In this context, we present a synopsis of the state of knowledge about the tenebrionids of Colombia by (1) compiling and updating the list of species of Tenebrionidae recorded from Colombia, based on the literature, (2) summarizing the known geographic distributions of each species in the country and determining endemism, (3) analyzing tenebrionid diversity in Colombia in the context of the Neotropical region, and (4) discussing priorities and guidelines to reduce the knowledge gap about this group in the country. This contribution serves as a baseline to initiate the study of darkling beetles in Colombia.

Checklist construction
The list of species of Tenebrionidae recorded from Colombia was initially extracted from Blackwelder (1944). For each taxon included we recorded: (1) author and year of description; (2) relevant bibliographic resources, including original description; (3) Colombian localities where each species has been documented; (4) information on type material when it was readily available from publications; (5) origin and habits of each species; (6) endemic status of each species; we considered Colombian endemics when no records from other countries were found in the published literature. Furthermore, recent taxonomic revisions were consulted to capture any additional taxonomic changes and records. Most publications of original descriptions are publicly available online via the Biodiversity Heritage Library (https://www.biodiversitylibrary.org/) and similar repositories. Those not available online were requested as interlibrary loans at the library of Texas Tech University, or by personal request from specialists. Finally, the classification of subfamilies and tribes was updated according to Bouchard et al. (2021).

Literature search for additional records
We performed a literature search following the PRISMA methodology (Moher et al. 2009), using the Jstor, Sage, Science Direct, Scielo, Scopus, Springer, and Web of Science databases from the following directed search equation to the title, abstract, and keywords section of each document: (tenebrionid* OR "darkling beetle*") AND (tropic* OR Neotropic* OR Colombia* OR Andes* OR Andean*), between January 1946 and February 2022. We found 345 articles, reduced to 119 after removing duplicates and articles that evaluated other beetle families. We accessed the full text of 119 articles and those meeting the following criteria were selected: (i) the article presents a list of darkling beetle species, and (ii) at least one darkling beetle species was recorded from Colombia. After considering these selection criteria, we found 25 articles.
Beyond original descriptions and new records, genus-and species-level records were obtained from the Coleoptera catalog of the Colección Taxonómica Nacional de Insectos Luis María Murillo (Vergara-N et al. 2021). These records correspond to species of agricultural importance, with a large proportion of the specimens collected between 1950 and 1980, and identified by international experts (Vergara-N, pers. comm.).

Taxonomic distribution overview
We found 326 darkling beetle species recorded from Colombia: 286 species from Blackwelder's checklist and 40 from additional publications ( Table 1). The darkling beetle checklist from Colombia is available as a Darwin Core-formatted checklist dataset via the Global Biodiversity Information Facility (GBIF) and the Sistema de Información sobre Biodiversidad de Colombia

Geographic distribution
We found that the department of Cundinamarca (including Bogotá) has the highest number of recorded species with 52, followed by Valle del Cauca with sixteen, and Bolívar with thirteen, resulting in greater representation of tenebrionids in the Andean, Caribbean, and Pacific regions of Colombia (Fig. 2). Eight departments only have records for a single species and ten do not have records of any tenebrionid species (Fig. 2). Records for four species in the country are considered doubtful and in need of confirmation (Platydema capitosum Chevrolat, 1877, Sycophantes substriatus Pic, 1921, Penichrus nannus Marcuzzi, 1998, andAcropteryx crenatum (Pic, 1914)). Tribolium castaneum (Herbst, 1797), Alegoria dilatata Laporte de Castelnau, 1840, Alphitobius laevigatus (Fabricius, 1781) and Alphitobius diaperinus (Panzer, 1797) are the most widespread species in Colombia, recorded from eight, seven, six, and four departments respectively; these species except Alegoria dilatata are considered introduced in the country.
Furthermore, ten species are recorded from only two departments and 99 species from only one department, whereas 190 (58.8%) species are recorded for Colombia without any specific locality within the country. For 136 (41.7%) species there is some locality information available, at least at the department level or with ambiguous localities. There are 16 species with localities that we were unable to unambiguously assign to a specific department (e.g., "Alto de las Cruces", "Las Pavas", "Río Magdalena", "San Antonio"). 185 species have been recorded only from Colombia, therefore, are considered endemic to the country.

Discussion
The lack of species-level geographic information is one of the main obstacles to conservation plans worldwide (Meyer et al. 2015). Despite advances in documenting biodiversity, only a few taxonomic groups have complete and updated regional or national checklists that include distributional information (e.g., Weigelt et al. 2020, Frost et al. 2022, Remsen et al. 2022). This lack of information is even more evident in megadiverse, developing countries like Colombia, where the number of national inventories has increased in recent years, especially in vertebrates including birds and amphibians (e.g., Avendaño et al. 2017, Acevedo-C et al. 2022). However, highly diverse groups like insects have been scarcely investigated (e.g., Noriega et al. 2015, Girón et al. 2021, and their knowledge in many cases is outdated (e.g., Medina et al. 2001), highlighting the need to provide updated information that allows for a better understanding of national biodiversity.
Colombian tenebrionid biodiversity in the regional context In Colombia, no local researchers have started studying tenebrionids from a taxonomic standpoint. The main contributions, in terms of species descriptions and new records, have been made by foreign researchers studying specimens housed in international collections (Fig. 1). The low number of tenebrionid species recorded from Colombia reflects the lack of specialized researchers (taxonomists) (Fernández 2011, Murcia et al. 2013, Hutchings and Hutchings 2017, Girón et al. 2021, Poulin and Presswell 2022, which ultimately results in knowledge gaps in the biological richness of many countries (Kassas 2002), with Colombia as an example of this situation (Amat and Escobar 2000).
On the other hand, the lack of a baseline limits our ability to approach the study of these megadiverse taxa, regarding their ecology and distribution (Davies and Cadotte 2011). One reason for the lack of a baseline is that the relevant literature is broadly scattered and sometimes difficult to access (Girón et al. 2021). With the checklist provided here, which compiles essential information for every single taxon recorded from Colombia, this baseline for Tenebrionidae is finally available. Ascuntar-O et al. (2023) contains a list of 265 documents published between 1873 and 2023 and provides links to digital versions of those publications available online, considerably reducing future efforts to track and compile information on Colombian tenebrionids.

Distribution of local diversity of darkling beetles in Colombia
As for many other insect taxa, most records of tenebrionids in Colombia are concentrated in the Andean region, with moderate numbers of records in the Caribbean and Pacific regions (Fig. 2).
Some of these records respond to specific and localized research efforts (e.g., Marcuzzi 1951Marcuzzi , 1954. Following the trend, the Orinoco and Amazon regions remain with very scarce specific records for the group, a situation that has been evidenced in other groups of arthropods as well (Girón et al. 2021, Palacino-R et al. 2022. This situation reflects known geographic biases in biodiversity research in Colombia (Arbeláez-C 2013), rather than an actual absence of darkling beetles in the south and eastern regions of the country.
However, records from Cundinamarca, especially those from 'Bogotá', need to be examined carefully as they might refer to the commercial/trade origin of the material rather than to actual collecting localities (see Paynter 1997). Based on specimens in national collections, other Colombian insect species (e.g., assassin bugs in the family Reduviidae, see Forero 2006) recorded in the literature from 'Bogotá' have been collected from localities in the departments of Antioquia, Chocó, Huila, Meta, Tolima, Santander, and Valle del Cauca, at lower elevations, making those records from Bogotá very doubtful and likely erroneous.
The vast majority of species have been described or recorded from specimens housed in international collections, whereas most tenebrionids housed in national collections are only identified to family, with at most only a few specimens identified to genus and species ( The nonexistence of specimens correctly identified at the species level in national collections can be attributed to both, the absence of national specialists and the lack of access to material from national collections to international specialists, either in the form of visits or the exchange of specimens. There are several issues surrounding these situations, but in general, it boils down to (1) the lack of funding opportunities to address biodiversity studies for national researchers, (2) the lack of communication and connectedness with the international community of specialists, and (3) national policies that limit our possibilities to collaborate with and learn from foreign experts.
For tenebrionids specifically, there is an entire community of international researchers willing to collaborate with local researchers with access to the local fauna. There is also interest from national budding taxonomists to contribute to the knowledge of Colombian biodiversity.
However, the lack of employment and funding opportunities deviates the attention of potential national specialists to better-funded topics or other career options. The Coleoptera de Colombia group (https://sites.google.com/view/coleopcol/) aims to establish a collaborative environment between national researchers, with the support of foreign specialists. This work is an example of what can be accomplished when we work together.

Conclusions and Perspectives on the Study of Tenebrionids in Colombia
The work we present here is only the first step towards understanding the biodiversity of darkling beetles in Colombia. Now we know that (1) the diversity of Colombian tenebrionids is understudied in comparison with other countries in the region, (2) we need to narrow down the distributions of the 190 species currently recorded for the country without specific localities, especially for those 185 species that are only known to occur in Colombia, 110 of which have no known localities within the country, and (3) we need to identify and report on specimens deposited in national collections.
Given our current state of knowledge and the need to further understand Colombian biodiversity, we recommend a clear, long-recognized goal (Escobar and Krieger 1999, Amat and Escobar 2000, Girón et al. 2021, to help bridge our knowledge gaps: make visible the identification status of different taxonomic groups in national collections. This information will allow us to establish work priorities and recognize where to focus research efforts. The best way to document and make visible information from national collections is through digitization efforts. Nowadays, there are several accessible options for managing data from biological collections (e.g., Gries et al. 2014) that can interact easily with the existing national infrastructure through SiB Colombia (https://biodiversidad.co/). The best existing example of what a national community can accomplish in terms of mobilizing data from biological collections is the Portal de Biodiversidad de Guatemala (https://biodiversidad.gt/portal/), where biological collections across the country have come together to digitize and make visible their national collections. These efforts must be supported and facilitated by national institutions. The absence of institutional support will only contribute to taking much longer to fill these knowledge gaps (Hutchings and Hutchings 2017) at a time when climate change and change in land use threaten biodiversity in Colombia and worldwide.

Acknowledgments
We dedicate this work to the memory of professor and colleague Germán Amat García, who encouraged curiosity and excitement about Colombian beetles and who promoted the idea to start building and updating species lists at the national level. We are grateful to the Coleoptera de