RESUMO
Leaf beetles (Coleoptera: Chrysomelidae) constitute a family of abundant, diverse, and ecologically important herbivorous insects, due to their high specificity with host plants, a close association with vegetation and a great sensitivity to microclimatic variation (factors that are modified gradually during the rainy and dry seasons). Therefore, the effects of seasonality (rainy and dry seasons) and microclimate on the community attributes of chrysomelids were evaluated in a semideciduous tropical forest fragment of northeastern Mexico. Monthly sampling was conducted, between March 2016 and February 2017, with an entomological sweep net in 18 plots of 20 × 20 m, randomly distributed from 320 to 480 m a.s.l. Seven microclimatic variables were simultaneously recorded during each of the samplings, using a portable weather station. In total, 216 samples were collected at the end of the study, of which 2,103 specimens, six subfamilies, 46 genera, and 71 species were obtained. The subfamily Galerucinae had the highest number of specimens and species in the study area, followed by Cassidinae. Seasonality caused significant changes in the abundance and number of leaf beetle species: highest richness was recorded in the rainy season, with 60 species, while the highest diversity (lowest dominance and highest H' index) was obtained in the dry season. Seasonal inventory completeness of leaf beetles approached (rainy season) or was higher (dry season) than 70%, while the faunistic similarity between seasons was 0.63%. The outlying mean index was significant in both seasons; of the seven microclimatic variables analyzed, only temperature, heat index, evapotranspiration and wind speed were significantly related to changes in abundance of Chrysomelidae. Association between microclimate and leaf beetles was higher in the dry season, with a difference in the value of importance of the abiotic variables. The results indicated that each species exhibited a different response pattern to the microclimate, depending on the season, which suggests that the species may exhibit modifications in their niche requirements according to abiotic conditions. However, the investigations must be replicated in other regions, in order to obtain a better characterization of the seasonal and microclimatic influence on the family Chrysomelidae.
RESUMO
Prathapanius Viswajyothi & Clark, gen. nov., is described and illustrated. The genus is placed in the chrysomelid section Diabroticites Chapuis (subtribe Diabroticina Chapuis, tribe Luperini Chapuis, subfamily Galerucinae Latreille). It is monobasic, containing Prathapanius fortis Viswajyothi & Clark, sp. nov., from Ecuador. The new genus is briefly compared with Acalymma Barber, Isotes Weise, and Zischkaita Bechyné.
RESUMO
Leaf beetles (Chrysomelidae: Coleoptera) constitute a highly diverse family of phytophagous insects with high ecological relevance, due to their host plant specificity and their close association to vegetation variables. Therefore, secondary succession and seasonal changes after loss of vegetal cover will have a significant influence on their community patterns. Accordingly, responses of leaf beetles to such environmental heterogeneity make them a suitable taxon for monitoring disturbance, which is more important for endangered habitats such as the low thorn forests (LTF) in northeastern Mexico. We conducted a study in a LTF fragment in order to assess the effects of secondary succession and seasonality on leaf beetle communities, as well as to quantify the importance of Chrysomelidae as an indicator taxon. Landsat scenes were used for delimiting a successional gradient, in which four succession categories were selected: four years, 17 years, and 31 years since loss of vegetal cover, and conserved areas. Eight plots of 100 m2 were randomly delimited in each category; plots were sampled monthly, using an entomological sweep net, from May 2016 to April 2017. In total, 384 samples were collected by the end of study, from which 6978 specimens, six subfamilies, 57 genera, and 85 species were obtained. Species richness was higher in early succession areas. Abundance declined significantly from early successional to conserved areas, but the conserved areas had the higher diversity. Furthermore, differences in abundance were significant between rainy and dry seasons in areas of four, 17, and 31 years of succession, but not in conserved areas; also, all categories had a similar abundance during the dry season. Intermediate (17 and 31 years) and conserved areas differed in the season of higher diversity. Regarding inventory completeness, it was close to or above 70 % for all comparisons, although it was very low for the 17-year category during the rainy season. Faunistic similarity was higher between intermediate categories. A total of 24 species had a significant indicator value. Effects of succession time and seasonality on leaf beetle communities are here quantified for first time in LTF forests. Influences of environmental heterogeneity and intermediate disturbance are discussed as main drivers of the results obtained. Several leaf beetle species are proposed that could be useful for monitoring succession time and secondary LTF vegetation in northeastern Mexico. However, studies must be replicated at other regions, in order to obtain a better characterization of disturbance influence on leaf beetles.
RESUMO
The study of biodiversity of Chrysomelidae in Mexico and its variation within ecological gradients has increased recently, although important areas in the country remain to be explored. We conducted a faunistic inventory and analyzed the elevational and temporal variation of leaf beetle communities in the Sierra de San Carlos, in the state of Tamaulipas, in northeastern Mexico. This is an area with high to extreme priority for conservation, and due to its insular geographical position and to the vegetational communities present, it must be considered as a sky island. We selected seven sample sites distributed in different elevations within three localities, and comprising different vegetational communities. At each site, we randomly delimited 12 sample plots of 400 m(2) where sampling was conducted by entomological sweep netting and collecting directly by hand. Sampling was conducted monthly at each plot, for a total of 1,008 samples between February 2013 and January 2014. By the end of the study, we had obtained a total of 3,081 specimens belonging to six subfamilies, 65 genera, and 113 species, with Trichaltica scabricula (Crotch, 1873) being recorded for first time in Mexico. Species richness was less than the values observed at other studies conducted in the same region, which is attributed to differences in the number of plant species and to the insular location of Sierra de San Carlos; however, the higher diversity values suggest a higher quality of natural resources and vegetational communities. No consistent pattern of leaf beetle communities was correlated with elevation, although higher values of species richness and diversity were obtained at the highest elevation site. The seasonal gradient showed that the rainy season is most favorable for leaf beetle communities. We found that species composition was different between sites and months, and also that there exists a significant association between the abundance obtained at each site and particular months. These results highlight the importance of different microhabitats for species distribution, and suggest that each species of Chrysomelidae has a differential response to environmental factors that vary within the elevational gradient and according to seasons. Also, we confirm and emphasize the important status of Sierra de San Carlos as a key natural area for biological conservation.
RESUMO
We record 116 genera and 366 species of Chrysomelidae from the state of Morelos, Mexico. This represents an increase of 9.3% in the species richness of these beetles for the state. Also, Morelos is currently the third most diverse state in leaf beetles within Mexico, with 16.78% of total species recorded for the country. The most diverse genera were Calligrapha, Disonycha, Blepharida, Leptinotarsa, Cryptocephalus, Systena, Alagoasa, Diabrotica and Pachybrachis, each with more than eight species. Most of these genera contain large, showy beetles. When the chrysomelid fauna is more fully understood, some of the genera of tiny beetles will likely prove to be more diverse.