Crabronidae (Hymenoptera: Apoidea) in Mexico: Occurrence and Potential Uses in Biological Control Crabronidae (Hymenoptera:

: The family Crabronidae (order Hymenoptera) includes excavating and hunting wasps of more than 9,009 species within 249 genera that are distributed globally, especially in the tropics. The objective of this research was to improve the knowledge of the occurrence of the family Crabronidae in Mexico from a review of the scientific literature and to provide data on species of importance in biological control. The results revealed that 769 species representing 99 genera have been reported in Mexico. With the current review, 8.5% of the species known worldwide were found to be present in the country and the list of species was increased by 32%. The genera Cerceris and Trypoxylon had the highest number of species, 130 species and 58 species, respectively. The Mexican states of Baja California Norte, Sonora and Tamaulipas have the highest number of Crabronidae species. A total of 211 species were added to the list of Crabronidae in Mexico. Twelve genera and eight species of Crabronidae used as biological control agents of various pests were recognized. Further research on the diversity of this group of insects is suggested, given the importance that crabonids have as predators and natural enemies of insect pests that affect economically important crops. se incrementó en un 32%. Los géneros Cerceris y Trypoxylon tienen el mayor número de especies, 130 y 58 especies, respectivamente. Los estados mexica- nos de Baja California Norte, Sonora y Tamaulipas reportaron el mayor número de especies de Crabronidae. Se agregaron un total de 211 especies a la lista de Crabronidae en México. Se reconocieron doce géneros y ocho especies de Crabronidae utilizados como agentes de control biológico en diversas plagas. Se sugiere realizar más investigaciones sobre la diversidad de este grupo de insectos, dada la importancia que los crabónidos tienen como depredadores y enemigos naturales de insectos plaga que afectan cultivos de importancia económica.


Introduction
Mexico is a shelter of 10 to 12% of the total species reported in the world and is one of the main mega-diversity countries, along with Brazil, Peru, Colombia, Indonesia, and China (Toledo 1988;Mittermeier and Goettsch 1992;González 2006;SEMAR-NAT 2008;Sarukhán et al. 2009;Martínez-Meyer et al. 2014). Such diversity includes an estimated 125,585 species of invertebrates, most of which are insects (SE-MARNAT 2008). According to Morón and Valenzuela-González (1993) and Luis et al. (2000), 110,000 species of insects have been reported in Mexico, which involves 6,000 species of Hemiptera, 20,000 species of Diptera, 35,000 species of Coleoptera, 2/9 and between 20,000 and 30,000 species of Hymenoptera (Michener 2000; Griswold et al. 2006).
The order Hymenoptera includes many species of ecological and economic importance (Fernández 2000;Della 2003;Guzmán 2014;Myartseva et al. 2014Myartseva et al. , 2015. Predatory wasps included in the superfamily Apoidea are distinguished because of their diversity of habits and behavioral complexity, ranging from solitary to eusocial species. Apoidea are advanced aculeates considered the most economically important insect group in the biological control (Brothers and Finnamore, 1993) and pollinators. The taxonomy of Apoidea is complicated due to the size of the insects, the relative scarcity of literature in some regions of the world, and the morphological similarity among closely related species (Ruíz et al. 2010).
The taxonomical criteria to separate groups vary according to different authors. For example, Bohart and Menke (1976) mentioned 11 subfamilies within the family Sphecidae, but further studies have elevated these subfamilies to the family level within the superfamily Apoidea (Gauld and Bolton, 1988). Finnamore and Michener (1993) classified these wasps into nine families grouped in the series Spheciformes, whereas Melo (1999) proposes four families, plus the family Apidae within the superfamily Apoidea. These four families are Ampulicidae, Crabronidae, Heterogynaidae, and Sphecidae, within the sphecoid wasps (Spheciformes) (Melo 1999), now apoid wasps. Moreover, Pulawski (2021) considered only the families Ampulicidae, Apidae Crabronidae, Heterogynaidae and Sphecidae.
About 8,000 species are known in Ampulicidae, Crabronidae, Heterogynaidae, and Sphecidae (Bohart and Menke 1976;Finnamore and Michener 1993). In the family Crabronidae,  cited about 9,106 species representing 249 genera and eight subfamilies, mainly from the tropics. The family Crabronidae represents 89% of the species present in the Americas from the apoid wasps, followed by Sphecidae (8%) and Ampulicidae with 2% (Table 1). The family Heterogynaidae have only been recorded in the Old World (Amarante, 2006;.  (Bohart and Menke 1976;Finnamore and Michener 1993;LaSalle and Gauld 1993;Was-bauer1995;Fernández 2000Fernández , 2002González 2006;Pitts et al. 2006;Horta et al. 2007Horta et al. , 2009Horta et al. , 2013Morrone and Márquez 2008;Orr et al. 2021 Previous studies of Crabronidae in Mexico recorded 558 species and 80 genera of crabronids (Horta et al. 2013), whereas Ruíz et al. (2002) listed 463 species, and Amarante (2002) reported 511 species. Such studies indicate that the families Crabronidae, Sphecidae, and Ampulicidae account for 8% of the species distributed in the Americas, highlighting Crabronidae as the most diverse family. This study aimed to update the number of species of the family Crabronidade in Mexico and provide data on species with potential use as biological control agents.

Materials and methods
A review of the available literature on the occurrence of the family Crabronidae in Mexico was conducted. This review included revising books, documents, and publications of scientific bases in the Journal Citation Reports (JCR), Latindex, and Scielo. Also, it involved other sources, such as reports of local studies in Mexico and databases available worldwide (Scullen 1972;Bohart and Menke 1976;Bohart 1990Bohart , 1993Bohart , 1997Bohart , 2000Antropov 1999;Ohl 1999;Leclercq 2000Leclercq , 2002aLeclercq , 2002bLeclercq , 2007Fernandez 2001;Amarante 2002Amarante , 2005Finnamore 2002;Genaro 2006;Holliday and Coelho 2006;Nemkov 2006;Horta et al. 2007Horta et al. , 2013Holliday et al. 2009;González et al. 2010;Looney et al. 2014;Vanoye-Eligio et al. 2014;Cancino et al. 2015;Rosa 2015;Ruíz-Cancino 2015;Vanoye-Eligio et al. 2015;Mokrousov and Popov 2016;Discovery Life 2018;GBIF 2018;Rosa and Melo 2020). The main criterion for the selection of species was that the record for Mexico is determined at the species level and preferably the place of collection in the different investigations. Any omission of relevant literature available was not intentional. In this study, we followed the classification of Melo (1999).

Discussion
The 769 species of Crabronidae reported from Mexico account for 8.5% of the total species reported worldwide (Pulawski 2022). Our report of 769 species also represents a 32% increase in the number of species previously provided by Horta et al. (2013), who listed 558 species and 80 genera. Other previous reports were 511 species by Amarante (2002) and 463 species by . Also, the study provides evidence of 11 genera and seven species present in Mexico that are recognized as biological control agents.
At the subfamily level, the Crabroninae had the most significant number of species in Mexico (338 species) (Tables 2, 3, Supplementary File), which coincides with other studies worldwide Horta et al. 2013;). According to , the diversity ranking of subfamilies of Crabronidae places Crabroninae as the most diverse subfamily, followed by Bembicinae and Philanthinae. However, in our review, Philanthinae and Bembicinae were the second and third most diverse subfamilies, respectively. Five genera (Cerceris Latreille, Eucerceris Cresson, Philanthus Fabricius, Clypeadon Patton, and Trachypus Klug) and 187 species comprised the subfamily Philanthinae. Cerceris was the most diverse genus with 70% of the species in that subfamily and represented 24% of the total species of Crabronidae. Such results are consistent with Horta et al. (2013), who reported Cerceris and Trypoxylon as the most representative genera of the family Crabronidae. Moreover, Vanoye et al. (2015) stated that Liris and Tachytes genera are also representatives of the family in Mexico. In this study, however, 36 of 99 genera are associated with only one species. In terms of species richness, the rarity of species within genera may suggest many unknown species inhabiting different regions of Mexico.
The states of Baja California Norte, Sonora, and Tamaulipas in the north of Mexico had the highest number of species with 144, 125, and 106 species, respectively. One explanation of this might be that the number of studies on Crabronidae is higher in this region than in other states of Mexico. In addition, another possible determining factor in the number of species of this family is the vegetation present in these states of the country, which have large plains and plains with hills forming part of the Sonoran and Chihuahuan desert (Gutiérrez-Ruacho et al. 2012). In these states the vegetation is varied, being the transition between the mountain vegetation and the vegetation of arid zones (Hernández et al. 2005). Toledo (1995) mentioned that these transition areas between various types of vegetation are rich in biodiversity. In addition to the above, the dominant vegetation in these areas is a desert scrub, which has open spaces that favor the abundance and richness of the family Crabronidae (Rzedowski and Huerta 1994;Comas et al. 2009;SEMARNAT 2011). This vegetation is characterized by thorny vegetation such as cactus and bromeliads and shrubs that ranged from 3 to 5 m high and in semi-desert pasture. Such environmental conditions provide open spaces preferred by wasps, as observed by Comas et al. (2009). Indeed, the species diversity of Crabronidae declines in closed or canopied habitats. Hymenoptera associated with open environments exploits the herbaceous plants and shrubs to provide food and nesting resources. Candia and Máyida (2005) found that structural differences between the arboreal strata and shrub vegetation influence the abundance and species richness of Crabronidae. In this regard, Genaro (2009) reported that nests of species of Cerceris are constructed in clay and compact soils without vegetation or sometimes with isolated low vegetation, as noted with C. victori (Genaro, 2009).
Of the 769 species reported from Mexico, records of 487 species (63%) provide information on state locations where they were collected, while reports on the remaining 282 species (27%) did not indicate specific locality data (Supplementary File). Overall, this review addressed the current knowledge of the diversity of species and its distribution of Crabronidae species in Mexico.
Regarding the use of insects in the natural control of pest insects, in agriculture, one of the objectives is to maintain biodiversity and promote the regulation of the abundance of harmful organisms, through predation, parasitoidism, parasitism and competition between species to reduce damage to crops (Brito and Camacho 2007). Agricultural and forest crops and other plant species of interest to humans offer excellent opportunities to develop integrated pest management programs, since there is a diversity of harmful and beneficial insect species in them that are in ecological balance and with healthy populations (León 2005). Pest insects limit the production of different crops. Ayala et al. (2013) mentioned that the damage they cause in crops is due to different environmental factors, the phenology of the crop and the habits of the pest insect, including the biological characteristics of the pest (Reséndiz et al. 2016). In biological control, parasitoids are the most widely used natural enemies of insect pests, as they play a fundamental role as natural regulators. Parasitoid wasps (Hymenoptera) constitute one of the most diverse orders of the class Insecta, which are used as natural control against insect pests (Llave 2015). Regarding predatory wasps, these have acquired great importance as predators of harmful organisms that affect agricultural crops, due to the pedotrophic behavior of these wasps, which includes several species of insects, caterpillars and spiders, and their nesting habits are variable, constructing them on different surfaces; in addition, there are wasps with solitary and social habits, which are considered to have important ecological characteristics which can help design conservation strategies and use in biological control (Brito and Camacho 2007;Meléndez-Ramírez et al. 2021). Hence, the use of Crabronidae species in the biological control of pests in forestry and agriculture has been important, since at least 22 cases have been documented for this purpose worldwide. In the subfamily Philanthinae, 10 species have been recorded (Cerceris arenaria (Linnaeus, 1758); C. californica; C. cerverae Giner-Mari, 1941;C. completa Banks, 1919;C. dilatata;C. fumipennis;C. grandis;C. jeiti Genaro, 2009;and C. victori) (Careless 2009;Genaro 2009;Careless et al. 2014;Looney et al. 2014;Polidori 2014;Klingeman 2015) that help in the control of pest species of Brupestidae (Coleoptera), which mainly affect wood. Five species and four genera of Crabroninae have been reported (Larra bicolor Fabricius, 1804; Oxybelus fritzi Bohart, 1993;O. platensis Brèthes, 1901;Solierella blaisdelli;S. peckhami;Holotachysphex; Liris; Tachysphex and Tachytes) which have been observed to include species of Hemiptera and Orthoptera (Nysius raphanus Howard; N. tenellus Barber; Gryllotalpa Latreille; Scapteriscus Scudder) in their pedotrophic diet, which affect different agricultural crops (Frank et al. 1995;Capinera and Leppla 2001;Seyoum and Pulawski 2001;Arévalo and Frank 2005;Ferreira et al. 2014;Polidori 2014;Gallardo-Granados et al. 2016;Carabali et al. 2017;Acosta 2018;De Carvalho et al. 2018;Gómez-Agudelo and Romero-Zúñiga 2018;Rial 2019;Sáenz-Romo et al. 2019). For Bembicinae two species have been recorded (Bicyrtes quadrifasciata (Say) and Rubrica surinamensis De Geer, 1778) preying on pest species that attack fruit and vegetable crops (Quispe 2015;Lara et al. 2016;Biddinger and Joshi 2017;Lowenstein et al. 2018). The subfamilies Astatinae and Pemphredoninae are each recorded with a species (Astata unicolor Say, 1824, and Pemphredon sp., respectively) considered as natural predators of pest insects in agricultural crops.
In Mexico, of the crabronid species for the purposes of induced or natural biological control that have been documented, seven species belonging to three genera have been recorded (Astata Latreille, 1796; Solierella Spinola, 1851; Cerceris Latreille, 1802), being the species Cerceris californica californica Cresson, 1865, with the greatest distribution in the country (11 states), mainly in the northeastern and northwestern states, and the same as the rest of the species. It is important to mention that the states of these regions are part of northern Mexico, where agriculture have managed to expand during the 20th century in millions of hectares with sophisticated irrigation systems, being a multiregional space that occupies about 60% of the Mexican territory and whose main characteristic is the aridity of the soil (Cerutti 2015), which is one of the determining factors in the richness and abundance of the family Crabronidae (Candia and Máyida 2005).

Conclusions
The results suggest that crabronids are a group of wasps with high species richness in Mexico, which is promoted by the combination of Nearctic and Neotropical elements that characterize this part of the Americas. This work added a total of 211 species to the Crabronidae species list and recorded seven species that have been used in the natural biological control of pests that affect the forestry and agricultural sector; however, given the ecological and economic importance of this group of insects, more research is needed on the diversity and biology of these wasps. Finally, it is important to highlight that despite the efforts that the scientific community worldwide makes by proposing species of insects as natural pest control agents, currently the main method of insect pest control is based on the use of chemical insecticides, which are of immediate action, because they have been effectively adapted.
However, the use of broad-spectrum chemical pesticides negatively affects both beneficial and harmful insects, including those with great potential in natural pest control.