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Bacterial symbionts play an important role in insect survival by contributing to key metabolic and defensive functions. While stingless bees are known to harbor diverse microbial communities, their core bacterial symbionts remain poorly characterized. In this study, we analyzed the gut microbiota of sixteen stingless bee species collected from different regions of Mexico using 16S rRNA gene sequencing on the Illumina® MiSeq™ platform. Our results revealed that Proteobacteria, Firmicutes, and Actinobacteria are the most abundant bacterial phyla across species. Among the dominant genera, lactic acid bacteria, such as Lactobacillus spp., Bifidobacterium, and Fructobacillus spp., were the most prevalent. These bacteria are responsible for developing biochemical functions in metabolic processes like lactic fermentation and the biotransformation of complex organic compounds into molecules that are more easily assimilated by bees. This study offers a novel perspective on the diversity and predicted composition of gut microbiota in Mexican stingless bees. By highlighting differences in microbial communities among species with different feeding habits, our results emphasize the importance of preserving microbial biodiversity in these pollinators.

Understanding the breeding ecology and trophic dynamics of the Swainson’s Hawk (Buteo swainsoni) is essential for conserving grassland raptor populations in northern Mexico. We evaluated reproductive success, nest-site characteristics, and diet of the species in the grasslands of Janos, Chihuahua, during the 2006 breeding season. Eighteen nests were monitored to estimate daily survival rates (DSRs) using the Mayfield method. Overall nest success was 44.4%. DSR declined significantly from incubation (0.99 ± 0.00079) to the nestling stage (0.98 ± 0.00087; z = 8.5, p < 0.001), resulting in cumulative survival of 79.9% and 56.2%, respectively. Successful nests tended to occur farther from towns, although this trend was not statistically significant. Most nests were built in mesquite trees at intermediate elevations and in areas with low human disturbance. Diet analyses of 56 pellets and 91 prey remains revealed a predominance of vertebrates (63.17%), mainly mammals and reptiles, with vertebrate frequency significantly exceeding that of invertebrates (χ2 = 23.19, p < 0.001). These results highlight the species’ reliance on vertebrate prey and the vulnerability of the nestling stage, underscoring the importance of long-term monitoring in semi-arid grasslands.

The dietary niche breadth of the Burrowing Owl was determined ( Athene cunicularia Molina, 1782) in Llano La Soledad, Galeana, Nuevo Leon in northern Mexico, by considering prey type, numerical percentage, weight, weight percentage, frequency of occurrence percentage, and IRI percentage. The study compared data from three winters (2002–2003, 2003–2004, 2004–2005) by analyzing 358 pellets, identifying 850 prey items. Invertebrates constituted 90% of prey items, which mostly included insects (85%); beetles were the most common insects found in pellets (70%). Vertebrates made up 84% of consumed weight, of which 83% were mammals. Most of the mammals were cricetid rodents (41%). Niche breadth based on the numerical and weight percentage confirmed the Burrowing Owl as a generalist species with mean values per year ranging between 0.65 and 0.82. Additionally, there was a strong association between the weight of rodent species in winter. This association was mainly driven by changes in composition and frequency of these prey species during the second winter, probably caused by high annual rainfall. The second season also showed a statistically significant narrower niche (Ro = 0.96) and the smallest overlap (0.45 vs . 0.76) among the three winters.

Bacterial symbionts in insects constitute a key factor for the survival of the host due to the benefits they provide. Parasitoid wasps are closely associated with viruses, bacteria, and fungi. However, the primary symbionts and their functions are not yet known. This study was undertaken to determine the gut microbiota of six species of the Telenomus genus: T. alecto (Crawford), T. sulculus Johnson, T. fariai Costa Lima, T. remus Nixon, T. podisi Ashmead, and T. lobatus Johnson & Bin. Wasp parasitoids were collected from their hosts in different locations in Mexico. DNA was extracted from gut collection, and sequencing of bacterial 16S rRNA was carried out in Illumina® MiSeq™. Among the six species of wasps, results showed that the most abundant phylum were Proteobacteria (82.3%), Actinobacteria (8.1%), and Firmicutes (7.8%). The most important genera were Delftia and Enterobacter. Seventeen bacteria species were found to be shared among the six species of wasps. The associate microbiota will help to understand the physiology of Telenomus to promote the use of these wasp parasitoids in the management of insect pests and as potential biomarkers to target new strategies to control pests.

The parasitoid wasp Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) has the potential for biological control against insect pests in stored grains, mainly of the orders Coleoptera and Lepidoptera. microRNAs (miRNAs) are small non-coding RNA fragments of importance in the regulation of gene translation in most physiological processes, and the study of miRNAs in wasps can be useful for understanding the physiology of these insects. The objective of this study was to evaluate for the first time the miRNomic profile of A. calandrae and to determine its conservation in five species of the order Hymenoptera (Apis mellifera, Dinoponera quadriceps, Nasonia giraulti, N. longicornis and N. vitripennis). Using molecular techniques and bioinformatics tools, a total of 108 miRNAs were identified (75 conserved between species and 34 de novo). These miRNAs were found to be related to embryogenesis, signaling, metabolic, biological and immune functions. The miRNomic signature of A. calandrae is important for the study of the physiology of wasps and the order Hymenoptera.

Background The western burrowing owl ( Athene cunicularia hypugaea ) occurs throughout western North America in various habitats such as desert, short-grass prairie and shrub-steppe, among others, where the main threat for this species is habitat loss. Range-wide declines have prompted a need for reliable estimates of its populations in Mexico, where the size of resident and migratory populations remain unknown. Results Our objective was to estimate the abundance and density of breeding western burrowing owl populations in Mexican prairie dog ( Cynomys mexicanus ) colonies in two sites located within the Chihuahuan Desert ecoregion in the states of Nuevo Leon and San Luis Potosi, Mexico. Line transect surveys were conducted from February to April of 2010 and 2011. Fifty 60 ha transects were analyzed using distance sampling to estimate owl and Mexican prairie dog populations. We estimated a population of 2026 owls (95 % CI 1756–2336) in 2010 and 2015 owls (95 % CI 1573–2317) in 2011 across 50 Mexican prairie dog colonies (20,529 ha). Conclusions The results represent the first systematic attempt to provide reliable evidence related to the size of the adult owl populations, within the largest and best preserved Mexican prairie dog colonies in Mexico.

The Long-billed Curlew (Numenius americanus) is a species of national and international conservation priority due to its population declines. Little is known about their migration patterns and there is limited research on the species in Mexico which prevents conservation biologists from establishing effective conservation measures for the species in North America. The southeastern portion of the Chihuahuan Desert is one of the last areas of well-preserved grasslands in Mexico and supports a large number of wintering Long-billed Curlews. We tracked four Long-billed Curlews using satellite telemetry to determine their winter habitat use from October 2009 to March 2010. Locations were divided into foraging and roosting sites (seven habitat types each) with agricultural fields and fallow land preferred for foraging. We identified 14 roosting sites and characterized the vegetation of six of them. Tumbleweed (Salsola kali) was the predominant plant species at roost sites. Two main threats were detected on wintering grounds: exposure to pesticides and reduced access to water. We successfully documented fidelity to wintering, breeding and stop-over sites across three migratory cycles (2009–2012) of one of the marked birds.

Ursus americanus Pallas 1780 is the largest carnivore and the only ursid in Mexico. It is considered an endangered species in the country because its distribution and population have been reduced by up to 80% because of habitat loss or furtive hunting. These problems can lead to a diet change, which could result in metabolic disorders, such as fatty acid β-oxidation defects or organic acid metabolism disorders. In our study, a free amino acid and acylcarnitine profile was characterized. Peripheral blood samples were drawn from nine free-ranging black bears in a period of five months, from June to October of 2019 in Northeastern Mexico, and 12 amino acids and 30 acylcarnitines were determined and quantified. Age differences were observed in the samples through ANOVA and post-hoc Tukey test. Only three metabolites showed a significant difference with age: alanine (Ala) [cubs vs juvenile], free-carnitine (C0) [juvenile vs cubs] and acetylcarnitine (C2) [cubs vs adults and juvenile vs cubs]. Metabolites with variability due to age were identified, making them potential biomarkers to monitor metabolic status as early diagnosis in endangered species. This is the first study of black bear amino acid and acylcarnitine profiles, and the values found could be used as reference for free amino acid and acylcarnitine concentrations in further studies of the species.

Aquatic wild birds, especially waterfowl, have been long considered the main reservoirs of the avian influenza A virus; however, recent surveys have found an important prevalence of these viruses among land birds as well. Migration has been suggested as an important factor in the avian influenza virus dissemination. We aimed to estimate the prevalence of influenza A viruses in wild birds (waterbirds and land birds; resident and migratory) in eastern Mexico, where the three main North American migration flyways converge and where there was no previous information on this subject. We detected influenza with reverse transcription coupled with a PCR approach. Of the 534 birds sampled between 2010 and 2012, we detected the influenza A virus in a high proportion of birds (39%). Prevalence was particularly high in land birds (49%) when compared to aquatic birds (26%); there was no difference in overall prevalence between resident (39%) and migratory birds (39%). The high prevalence of the avian influenza virus in land birds was noteworthy in the innermost sampling areas in northern Mexico (Coahuila [82%] and Nuevo Leon [43%]).

Heavy metals exposure has been linked to severe health problems. In Mexico, the Monterrey metropolitan area (MMA) is considered one of the most polluted industrial regions. Because birds have been used successfully as environmental biomonitors, the levels of lead, cadmium, and arsenic in feathers of Great-tailed grackles (Quiscalusmexicanus) from two sites within and one site outside the MMA were determined. One hundred birds were captured, samples were analyzed by atomic absorption spectrometry. Ciudad Universitaria had the highest mean values of lead and cadmium, 11.91 ppm d.w. and 1.66 ppm d.w., respectively. This was at least, 10- and 8-times higher than the two other sample sites. We believe that using Great-tailed grackles as bioindicators in conjunction with air pollutants sampling from meteorological stations in Monterrey City could help in making decisions when applying environmental remediation measures as well as in the selection of places for housing, school and work among others.