Spatiotemporal Diversity of Scolytinae (Coleoptera: Curculionidae) in Three Ecosystems of Villaflores, Chiapas

: The diversity of scolitines associated with jungles and a rustic coffee plantation in the municipality of Villaflores, Chiapas, was determined during the period from August 2020 to July 2021. The insects were captured using Ecoiapar traps with ethyl alcohol as attractant. A total of 3745 individuals of scolitines were collected, grouped into 28 genera and 64 species; the species Corthylus rubricollis and Cryptocarenus laevigatus are new records for Mexico. In jungles and coffee plantations, the richest genera were Corthylus, Xyleborus, Hypothenemus and Cryptocarenus. The maximum index of diversity of scolitines determined with the Shannon-Wiener index was in the locality of Guaymas (H': 2.979); with the Margalef index, the maximum specific richness was in Roblada (DMG: 7.073). On the other hand, with the equity index, the maximum value was obtained in Guaymas (J': 0.7654); while, with the Jaccarf similarity index, the Guaymas-Roblada localities present a greater number of species in common. The scolitine population fluctuated constantly, presenting two very marked population peaks, the first in the winter season in March with 782 individuals, the second in the summer in September with 62 individuals. By locality, the populations of scolitines fluctuated constantly, with the highest number of insects recorded in the winter and spring seasons, during the dry season and at the beginning of the rainy season.


Introduction
Villaflores is a municipality in the state of Chiapas that stands out for its agricultural and livestock production at the regional and state level; Environmentally, it is characterized by presenting great wealth of natural resources and diversity of flora and fauna [1].However, studies of insect diversity in Villaflores are few and are oriented towards crops of agricultural importance such as canavalia and piñon [2,3] and beetles.melolontids and the superfamily Curculionoidea [4,5].However, in Villaflores no studies of scolitine diversity have been carried out, being these of great importance in agricultural and forestry crops in Mexico.
The beetles of the Scolytinae subfamily (Coleoptera: Curculionidae) present worldwide distribution and different roles in nature.Due to their feeding habits they are classified as spermatophages, myelophages, bark-eaters, borers and ambrosia, and due to their ecological interactions they are considered important components of ecosystems by contributing to the stability and nutrient balance of plant communities [6].In the world, around 6000 species of scolitins distributed in 247 genera are known [7,8].In Mexico, there are around 870 species in 91 genera [9,10]; of these, less than 5% are considered phytosanitary and Carlos Eduardo Aguilar-Castillo et al.: Spatiotemporal Diversity of Scolytinae (Coleoptera: Curculionidae) in Three Ecosystems of Villaflores, Chiapas quarantine pests of economic importance, for infesting trees, shrubs and herbs of forestry, fruit and ornamental interest [6,11].However, phytosanitary problems in relation to scolitins arise from native or introduced species, which establish themselves in plants affected by biotic and abiotic factors [12,13].
In many parts of Mexico, diversity and monitoring work has been directed at pine forests and crops of economic interest such as cocoa, avocado and teak [14,13,6], while in tropical and subtropical zones they are oriented towards natural vegetation and mangroves [15,16,17].In general, the scolitines represent a great threat to these ecosystems and agroecosystems; therefore, the knowledge of diversity through the registration of species and location zones are important tools for the prevention of affectations through the timely detection of species of economic importance [18].Some examples of complex ecosystems where the interaction of plants and scolitine species need better exploration are forests and some crops associated with these ecosystems, such as coffee plantations; where the works in relation to scolitin diversity are scarce, and focus on species of economic importance that damage the fruit, branches and shoots of the coffee plant [19,20,21].Therefore, the objective of this research was to know the spatiotemporal diversity of scolitine species in forests and a coffee plantation in the municipality of Villaflores, Chiapas.

Materials and Method
Study zone.The collection of insects was carried out in three locations in the municipality of Villaflores, Chiapas.The towns of Jesús María Garza (16° 41' 91¨ N and 93° 26' 24¨ W) and Roblada (16° 39' 01¨ N and 93° 24' 67¨ W) are made up of low deciduous forest vegetation, while Guaymas (16° 46' 92¨ N and 93° 24' 43¨ W) is made up of semideciduous forest vegetation with rustic or mountain coffee plantations.The municipality presents an average annual temperature that ranges between 14 and 27°C, with average rainfall that ranges from 1,000 to 3,500 mm; the predominant climates are semi-warm and warm sub-humid with rains in summer (13.05 and 60.30%); the dominant types of vegetation are forests and jungles (low and medium) with 32.21 and 15.77% respectively [22,23].
Trap setting.In each locality, ten Ecoiapar artisanal traps described by Barrera and collaborators in 2004 [24] and modified by Moreno y collaborators in the year 2005 [25].Each trap was labeled with the name of the location, date, and trap number.The separation between the traps was 50 m, each one suspended 1.5 m above the ground on tree branches and held from the top and bottom to prevent them from falling due to the wind.The traps were placed in a transect in plots of 2 ha.In the middle part of each trap, the bait was set, consisting of 50 ml Falcon tubes with 96% ethyl cane alcohol, which was released through two one-millimeter-diameter holes located in the upper part of the bottle.The collecting vessel was provided with 200 ml of propylene glycol (antifreeze) diluted in water to 50 % to preserve the captured specimens until their collection.
Insect collection and identification.The collection of insects was carried out on a monthly basis, during the sampling period from August 2020 to July 2021.The captured insects were placed in Ziploc® bags with their respective data and 70% alcohol for their conservation.The samples were taken to the Forest Entomology laboratory of the Postgraduate College; for their separation, counting and mounting on entomological pins.The taxonomic determination of species was carried out using the taxonomic keys of [26,27,28]; in addition to comparisons with specimens deposited in the insect collection of the Colegio de Postgraduados, Campus Montecillo, Texcoco, State of Mexico.Species corroboration was performed by Dr. Armando Equihua Martinez.
Data analysis to determine the diversity of scolitins.In order to know and compare the diversity of scolitins in coffee plantations in the three study sites, the Shannon-Wiener (H´) diversity indices were applied, which measures the structure of the community through the uniformity of the importance values at across all species in the sample; the Margalef index (DMG), which is based on the specific richness of species, and the Pielou equity index (J´), which measures the proportion of observed diversity in relation to the maximum expected diversity [29,30].Subsequently, to know the proportions or differences of species between the study sites, the Jaccard index (Ij) was used, which expresses the degree to which various sites are similar due to the species present in them [29].The analyzes were performed using the statistical program PAST3 version 3.20.

Results
Analysis to determine the richness and abundance of scolitins in forests and a coffee plantation 3,745 scolitins individuals belonging to 64 species and 28 genera were collected; of these, the species Corthylus rubricollis Blandford and Cryptocarenus laevigatus Blandford, constitute new records for Mexico; for Chiapas, 23 new species were registered, which represent an increase of 13.52% in relation to the species of scolitines previously registered in the state [31,32,33].In the three study locations, the genera with the greatest richness were Corthylus, Xyleborus, Hypothenemus and Cryptocarenus with 10, 7, 7 and 6 species, respectively (Table 1).
According to the localities, in Roblada the greatest abundance of scolitines was recorded with 1,559 specimens, compared to Guaymas and Jesús María Garza, where 1,304 and 882 individuals were captured, respectively.On the other hand, in the three locations the most abundant species were Xyleborus spinulosus Blandford (14.29%),Taurodemus sharpi Blandford (11.75%),Premnobius cavipennis Eichhoff (10.81%) and C. rubricollis (10.17%), equivalent to 42.02 % in comparison with the rest of the scolitin species.By locality, the same species of scolitins were found, but in different percentages; In Roblada the abundant species were X. spinulosus (  With the Shannon-Wiener index (H´) it was obtained that the maximum diversity of scolitins was found in Guaymas (H´: 2,979) and the minimum in Jesus Maria Garza (H´: 2,571); with the Margalef index (DMG) it was determined that the maximum specific richness occurs in Roblada (DMG: 7,073) and the minimum in Jesus Maria Garza (DMG: 5,898).Regarding the equity index (J´), the maximum value was obtained by Guaymas (J´: 0.7654); while the lowest value was Roblada (J´: 0.685) (Table 2).On the other hand, the Jaccard similarity index (Ij) determined that the Guaymas-Roblada localities present a greater number of species in common (Ij: 0.672) compared to the Guaymas-Jesus Maria Garza localities (Ij: 0.666) and Roblada-Jesus Maria Garza (Ij: 0.593) (Figure 1).The population fluctuation of scolitines in jungles and a rusticano coffee plantation in Villaflores, Chiapas.In each location, two population peaks were recorded throughout the study year; the first in winter in the month of March with 782 individuals, the second in the spring season in the month of June with 637 individuals.On the other hand, in summer during September the lowest abundance of insects was presented with 62 individuals captured (Figure 2).
On the other hand, the species with the highest abundance in the three sampling locations were X. spinulosus, T. sharpi, P. cavipennis, C. rubricollis and C. papulans with 535, 440, 405, 381 and 357 individuals respectively.The populations of these insects fluctuated considerably during the monitoring year; the scolitins X. spinulosus, T. sharpi and P. cavipennis reached their highest population abundances in the month of March with 215, 207 and 218 individuals respectively, to drastically decrease their populations during the year.In contrast, the populations of the species C. rubricollis and C. papulans fluctuated uniformly, presenting their highest population abundance in the months of June and January with 84 and 49 individuals respectively (Figure 3).
By locality, the populations of scolitines increased considerably in the months of collection; presenting for each locality two population peaks of greater abundance during the winter and spring seasons, that is, during the course of the dry season and the beginning of the rainy season.In Roblada, the months of greatest abundance were March and June with 353 and 313 individuals respectively.In this locality, the species with the highest population abundance were X.In Guaymas, the collection pattern was similar to Roblada, although with fewer captures on the two dates, that is, 248 and 219 individuals.In this locality, the most abundant species were T. sharpi, C. rubricollis, P.

Discussion
In the municipality of Villaflores, the diversity of scolitine species was high; with 24 new records for Chiapas, which represent an increase of 13.52%;In addition, Corthylus rubricollis and Cryptocarenus laevigatus are new records for Mexico, based on the research carried out by Equihua and Burgos in 2002 and Atkinson in 2021 [31,33], who state that they have no records of these species in Mexico.On the other hand, the genera Corthylus, Xyleborus, Criptocarenus and Hypothenemus are the most abundant in the monitoring systems, they are considered common and abundant organisms as they present a high reproductive rate, a great variety of host plants and a wide distribution in tropical and subtropical regions of the world [26,10].Of the four genera, in the three study sites the genus Corthylus was the one with the highest species richness with ten species; These results are similar to what was reported in the cloud forest of Xalapa, Veracruz by Atkinson and Ibarra in 2021 [34], who report 16 Corthylus species.On the other hand, the diversity of species of the genera Xyleborus and Hypothenemus in Villaflores was relatively high, as in research carried out by Estrada and Atkinson, Pérez-De la Cruz and collaborators, and Falcón-Ecosystems of Villaflores, Chiapas Brindis and collaborators in the year of 1988, 2009 and 2018 [35,14,36] in forest ecosystems, floodplain grasslands and mangroves, and in agricultural crops such as cocoa.In the case of the genus Cryptocarenus, six species were recorded, which contrasts with diversity studies in mangroves in Tabasco and avocado crops in Michoacán, where two and three species were captured respectively [37,38].
By species, X. spinulosus was the most abundant scolithin during the annual monitoring cycle; However, despite being an insect that is commonly captured in various states of Mexico and other countries in the world, its populations are relatively low in natural vegetation and forest plantations in Ecuador [39] and jungles of Tabasco, Mexico [17].While the records of T. sharpi are greater than those reported by other authors, even though it is a species with a wide distribution from southern Mexico to Panama [33], few studies report the presence of this species.Insect in tropical forests of southern Mexico (Chiapas, Oaxaca, Veracruz and Tabasco), where few individuals have been collected compared to those captured in the monitoring sites of this research [40,17].In the same way, the records of P. cavipennis were lower in coffee plantations with 95 individuals and abundant in low deciduous forests with 173 and 137 individuals, than those reported by Averos and collaborators in 2021 [41] who report 4170 individuals of this species in the central zone of the Ecuadorian coast.On the other hand, [42] Wood in 2007 describes P. cavipennis as a species with a wide geographical distribution; In the American continent it is found from the southern United States to Brazil, with a wide variety of hosts [42], this distribution in the world has allowed it to colonize various types of ecosystems such as tropical forests, floodplain grasslands, mangrove swamps and xeric scrub.[43,36,44,37] and some economically important crops such as cocoa, avocado, teak and balso [45,38,46,41]; In most of these investigations, the populations of P. cavipennis are low compared to that found in this study, with the exception of the results obtained by Falcón-Brindis and collaborators, Belezaca and collaborators, and Averos y collaborators in the years 2018, 2020 and 2021 respectively [36,46,41], where P. cavipennis was the dominant species.Finally, C. rubricollis was abundant in the low deciduous forest of Roblada and coffee plantations of Guaymas with 164 and 171 individuals respectively; In Mexico there is no record of this species in diversity studies and the little information comes from Central and South American countries such as Costa Rica, Panama and Colombia [47,26,48].
The diversity and similarity indexes used in each one of the localities, allowed to determine the differences in the diversity and abundance of species; The highest species richness using the diversity indices was recorded in the towns of Roblada and Guaymas, which present small significant differences in the results obtained, while Jesús Ma.Garza was the least diverse site; This difference was due to the elements that make up each environment, in which biotic factors such as temperature, humidity, precipitation and altitude, and abiotic factors such as food availability, predation and competition are those that determine the richness and abundance of these insects in various ecosystems.and agroecosystems [26,14].On the other hand, the equity index determined that in rusticano coffee the species are equally abundant, compared to localities with natural vegetation, [36] Falcón and collaborators in 2018, mention that modifying ecosystems for agricultural use contributes to the loss of the diversity of insects, but favors the establishment and increase of the populations of generalist and agriculturally important species, such as H. hampei, H. interstitialis, X. affinis, X. volvulus and X. morigerus.Finally, the similarity index showed that the Guaymas and Roblada localities present a greater number of species in common; compared to the towns of Roblada and Guaymas, despite being at the same altitude and type of low sub-deciduous forest vegetation.

Conclusion
This is the first contribution to the knowledge of the diversity, abundance, and population fluctuation of scolitines in forests and rusticano coffee plantations in the municipality of Villaflores, Chiapas.Which provides new records for the state of Chiapas and Mexico; and species of economic importance such as H. hampei, X. curtulus, X. morigerus and some species of the genus Xyleborus, which require followup to reduce their impact on crops, which can be with the use of artisanal traps baited with ethanol, which are accessible, easy to use and provide information on the population structure for decision-making in the management and control of these insects in various forest and agroforestry ecosystems where they live.

Figure 3 .
Figure 3. Population fluctuation of the most abundant scolitins during the monitoring year in Villaflores, Chiapas.
cavipennis and C. detrimentosus with 283, 171, 95 and 92 individuals; whereas, the species with only one individual were A. hagedorni, A. obliquos, B. foveatus, D. tuberculatus, M. festiva, P. hispidum, S. ingavorus and X. morigerus.Finally, in Jesus Maria Garza the pattern of maximum catches was different from the other two locations, in this case it was recorded in winter in the months of February, March and April with 118, 181 and 123 individuals.The species with the highest representation were T. sharpi, C. papulans and P. cavipennis with 179, 144 and 137 individuals.Instead, the species with unique records were A. obliquos, C. aciculatus, C. aguacatensis, C. nudus, D. capucinus, P. attenuatus and X. horridus.