Insects Breeding in Pig Carrion in Two Environments of a Rural Area of the State of Minas Gerais, Brazil

The main objective of this study was to identify potential forensic indicators in the insect fauna associated with pig carrion and the pattern of insect succession during the decomposition process in two environments of a rural area in Uberlândia, State of Minas Gerais, Brazil. The study was conducted at two locations: in a pasture and in a fragment of a semi-deciduous forest (vegetation profile of the Cerrado biome) in two different seasons (rainy and dry) of 2010. The decomposition process was more rapid in the rainy season. More than 32,000 insects belonging to 17 species of 6 families of Diptera and 2 species of Coleoptera bred in the carcasses. The majority of Diptera bred in the first three stages of decomposition. However, Phoridae and Coleoptera bred mainly in the last two stages. The insects bred more abundantly in the pasture and in the humid season. The exceptions were the Fanniidae (Diptera), which bred more abundantly in the forest and the Dermestidae and Cleridae (Coleoptera), which did not demonstrate any preference in terms of environments and were more abundant in the dry season, respectively. Species such as Chrysomya albiceps (Wiedemann), Peckia (Patonella) intermutans (Walker), Necrobia rufipes (De Geer), and Dermestes maculatus (De Geer) may be potential indicators of post-mortem interval. Hemilucilia segmentaria (Fabricius) and Ophyra aenescens (Wiedemann) may be indicators of localization of the natural environment, while Musca domestica Linnaeus may be an indicator of the anthropic environment. The study thus presented many species of potential forensic indicators in rural areas of this region.     

Diversity,Daily Flight Activity and Temporal Occurrence of Necrophagous Diptera Associated with Decomposing Carcasses in a Semi-Arid Environment

The harsh conditions of the Brazilian seasonally dry tropical forest known as Caatinga pose challenges to the insects specialized in the exploitation of ephemeral resources. We investigated the diversity and daily flight activity of dipterans associated with decomposing rat carcasses in a field experiment performed in the semi-arid region of Pernambuco State, Brazil. We also analyzed the temporal arrival of adult insects on the carcasses at three stages of decomposition: early, intermediate, and advanced. We collected 1173 individuals, of which Muscidae had the highest abundance (36.5%), followed by Sarcophagidae (28.1%), Calliphoridae (25.2%), and Fanniidae (10.2%). Chrysomya albiceps (Wiedemann, 1819) (Calliphoridae), Fannia pusio (Wiedemann, 1830) (Fanniidae), Atherigona orientalis (Schiner, 1868), and Musca domestica (Linnaeus, 1758) (Muscidae) were the most abundant species. The richness reached its maximum value on the second day of decomposition, with 18 species, decreasing to 8 species on the last day of decomposition (7 days). The ecological indices of diversity, dominance, and evenness varied little among the stages. There was an overlap of most species throughout the decomposition, although the overall abundance was higher at the intermediate stage for Calliphoridae, Muscidae, and Sarcophagidae. In accordance to previous studies, nocturnal flight was rare, as approximately 8% of insects were captured at night. Our results expand the knowledge on ecological and behavioral aspects of necrophagous flies under inhospitable environments, such as the dry season in the Caatinga. The dominance of the invasive species C. albiceps reinforced here illustrates its geographical expansion towards the countryside of Northeastern Brazil.     

Diversity of parasites in Cichlasoma amazonarum Kullander, 1983 during rainy and dry seasons in eastern Amazon (Brazil)

This study investigated the influence of the rainy and dry seasons on the parasite communities of Cichlasoma amazonarum (Kullander, 1983) in a tributary of the Amazon River system, northern Brazil. Of 112 fish examined, 95.5% were parasitized by Ichthyophthirius multifiliis, Piscinoodinium pillulare, Gussevia disparoides, Posthodiplostomum sp., Procamallanus (Spirocamallanus) inopinatus, and Echinorhynchus paranensis, as well as by the Glossiphoniidae leech. Ichthyophthirius multifiliis and P. pillulare were the dominant parasite species, with I. multifiliis the most prevalent and abundant; the leech (Glossiphoniidae) was the least prevalent and least abundant. Parasites presented an aggregate dispersion pattern and seasonal variations in infestation levels, influenced by the environmental conditions in the rainy season. Variation in the parasite dynamics created overall changes in the parasite communities, characterized by greater diversity, species richness and evenness during the rainy season. However, there was a high similarity (99.8%) in the parasite community structure between the rainy and dry seasons. During the dry season the hosts had predominantly 1–3 parasite species compared to 3–4 parasites in the rainy season. Some parasites in the eastern Amazon undergo population changes relating to seasonality. These results thus indicate the correct season to apply adequate prophylactic measures to reduce negative impacts of parasites in this wild ornamental fish when captured.     

Occurrence and distribution of fresh-water molluscs in the Riacho Fundo Creek Basin,Brasilia, Brazil

To study the distribution of molluscs in the Riacho Fundo Creek (cerrado region of central Brazil), five creek sites were sampled once every two months for one year. Molluscs were sampled using standardized kick-net sampling. Four species of molluscs were found: Physella cubensis, Melanoides tuberculata, Biomphalaria straminea and Pisidium sp. The most abundant were P. cubensis and Pisidium sp. Physella cubensis was most abundant in the dry season and Pisidium sp. was most abundant in the rainy season, probably reflecting the rainy season increase of water currents.     

Notes on phenology and abundance of Psocoptera from primary and secondary dryland forest in Central Amazonia,Brazil

Psocoptera were collected from soil (by Kempson extraction) and from tree trunks (by arboreal photoeclectors) at two contrasting sites near Manaus, Brazil, for one year. The predominant soil taxa were Epipsocetae, especially Isthmopsocus, and a number of minor constituents are probably casual litter‐frequenters. Tree trunks yielded several taxa absent from soil. Soil in a secondary forest site yielded about four times as many psocids as a primary forest site and psocids were more abundant in the dry season than in the rainy season. Arboreal photoeclectors collected more psocids in the primary forest, but catches at both sites were larger in the dry season than in the rainy season. About 81 per cent of the psocids were immature stages.     

Insects Associated with Pig Carrion in Two Environments of the Brazilian Savanna

Studies of carrion fauna have increased in Brazil and have contributed to the knowledge of this fauna in the national territory. Brazil has continental dimensions and presents various biomes in its territorial area. Most of the carrion fauna have seldom been studied, and this is especially true for the Savanna or “Cerrado.” The present research examined the fauna visiting carrion in two environments and two seasons in a rural area situated in a region of Cerrado in southeastern Brazil. The two environments studied were a pasture and a fragment of semi-deciduous forest. Samples were collected during the dry and humid seasons of the year. The study identified the diversity and relative abundance of species attracted to pig carcasses (Sus scrofa L.) exposed in each environment and season. Eight pig carcasses (10 ± 1 kg) were placed in traps, and adult insects attracted to the traps were collected during the decay of the carcasses. A total of 92,489 insects were collected during the experiments. The Diptera was the most frequent order (92.2%) represented by 27 families and at least 124 species. This was followed by Coleoptera (4.4%) represented by 14 families and at least 65 species. Sarcophagidae had the greatest diversity of species, followed by Muscidae and Calliphoridae. Several species were collected only during a specific period of the year or in a single environment. The results are important from an ecological point of view and for Medico-Legal Forensic Entomology.     

Succession of Carrion Fauna in the Arid Region of San Juan Province, Argentina and Its Forensic Relevance

The succession of carrion fauna and the decomposition stages were studied in the arid environment of San Juan Province, Argentina (31°32??34.7?? S; 68°34??39.4?? W). Two pig carcasses (Sus scrofa) were placed in wire mesh cages, 100?m apart from each other. Each carcass was surrounded by pitfall traps, and a modified Malaise trap was placed above. Daily samplings were carried out to collect the insects present in the carcasses and the traps, and body and environmental temperature were measured. The main colonizer species was Chrysomya albiceps (Wiedemann) and its larvae were dominant over other Diptera. The first adult blowflies emerged at 8.9?days. The time to reach the remains stage was 8?days shorter than for other South American sites. We recorded the early arrival of adult Dermestes maculates De Geer and Dermestes ater De Geer 2?days after the beginning of the assay, and larvae of these species were recorded 4?days after. We determined a 1.5-day error in the postmortem interval estimation using the temperatures measured in the assay and those recorded by the nearest meteorological station.     

Effect of vertebrate feces on the attraction of Culicoides (Diptera: Ceratopogonidae) in an Amazonian mangrove

Biting midges are of interest to public health because they play an important role as vectors of disease‐causing pathogens, as well as being a biting nuisance to humans and domestic animals. Although these insects are common in mangrove areas, they have not yet been studied in this ecosystem in the state of Maranhão (MA), Brazil. The objective of this study was to characterize the Culicoides community structure found in a mangrove swamp and verify if the use of vertebrate feces as bait interferes with their composition, richness, abundance, or seasonality. CDC light traps with vertebrate (chicken, ox, control, donkey, capuchin monkey and pig) feces baits were used to capture biting midges in a mangrove area of the Island of São Luís, MA. A total of 4,087 individuals representing 22 species of Culicoides were captured, the most abundant being C. (Oecacta) furens Poey (23.46%), C. (gr. Fluviatilis) leopoldoi Ortiz (21.58%), C. (Hoffmania) ignacioi Forattini (16.98%), C. (Hoffmania) maruim Lutz (13.85%), C. (Diphaomyia) iriartei Fox (10.57%), C. (Hoffmania) insignis Lutz (7.07%), and C. (gr. Limai) limai Barreto (3.03%). Species richness and abundance were higher when baits of capuchin monkey (15 species; 26.84% of the individuals) and pig (15; 25.3%) feces were used. The least attractive baits were donkey (12 species; 9.3%) and ox (nine species; 11.52%) feces. Biting midges were more abundant in the rainy season (67%), but richness was higher in the dry season (19 species). These results show that vertebrate feces may serve as olfactory cues and increase the attraction of biting midges to traps.     

Diversity and Synanthropy of Calliphoridae (Diptera) in the Region of Rio Claro, SP, Brazil

Dipteran blowflies (Calliphoridae) are of great medical and hygienic importance as vectors of pathogens and as parasites of living and dead tissue, and their association with carrion allows their use in forensic entomology. The objective of this study was to determine the synanthropic index of adult Calliphoridae (Diptera) collected in Rio Claro, S?o Paulo. Sampling occurred between September 2009 and August 2010. Traps baited with sardines, beef liver, and minced meat were assessed for five consecutive days per month in three distinct ecological areas representing urban, rural, and forest environments. The most abundant species was Lucilia eximia (Wiedemann), followed by Chrysomya albiceps (Wiedemann) and Chrysomya megacephala (Fabricius). Lucilia eximia was the only species present in all seasons and the only species collected during the winter. The season with the lowest abundance was winter, with 69 (5.5%) specimens, and spring was the season with the greatest number of specimens collected (774?C61.8%). The only species found outside inhabited areas (synanthropic) was Lucilia cuprina (Wiedemann), with a synanthropy index (SI) value of +5.7. The SI values for the other species were negative, showing a preference for uninhabited areas. The rural and urban areas were most similar in terms of species composition as were the beef and sardine baits. Among the baits used, liver attracted the greatest abundance of calliphorids, whereas minced meat attracted the greatest diversity.     

Species assemblages of cyclopoid Copepoda from Mantecal,Venezuela

A 14 year monitoring of species composition and abundance of cyclopoid copepods throughout the rainy and dry seasons in a flooded savanna at Mantecal, Apure State, Venezuela, is presented. Two characteristic habitats within these water bodies were selected: the open center of small ponds free of emergent vegetation and the surrounding flooded grassland. In total, 13 species were registered, all of which appeared in the flooded grassland and 11 of which occurred in the open water. Ten species were common for the two habitats during the dry season. The highest abundance was found in flooded grassland during the dry season. Eight species showed abundances greater than 1.0 individual per liter in flooded grassland during both seasons; 3 and 7 species were this abundant in the open water during rainy and dry seasons, respectively. Mesocyclops meridianus and Microcyclops varicans were the most abundant species in both habitats and seasons, while Thermocyclops decipiens was the dominant species during rainy season in open water. Principal component analysis indicates that the important species were positively correlated between them (sharing habitat and season).     

Seasonal variation in abundance and diversity of eavesdropping frog‐biting midges (Diptera,Corethrellidae) in a neotropical rainforest

1. In the tropics, precipitation patterns result in seasonal fluctuations in the abundance and distribution of plant and animal species. Tropical predators and parasites are therefore faced with seasonal changes in prey and host availability. 2. This study investigates the seasonal interaction among a specialised ectoparasite, eavesdropping frog‐biting midges (Corethrella spp.), and their anuran hosts, examining how the abundance and diversity of the frog‐biting midge community fluctuate between the rainy (host abundant) and dry (host sparse) seasons. 3. Midges were captured in both the rainy and dry seasons using acoustic playbacks of calls from a common frog species that breeds during the rainy season, the túngara frog (Engystomops, Physalaemus, pustulosus). During the dry season túngara frog choruses are absent. To explore seasonal shifts in host preference or changes in the midge community due to host specificity, midges were also captured using playbacks of calls from a frog that breeds during the dry season, the pug‐nosed tree frog (Smilisca sila). 4. While the overall abundance of midges decreased in the dry season, only slight differences in the relative abundance between midge species were found. These results suggest that midge populations can shift between hosts as they become available across seasons, allowing adult populations of frog‐biting midges to persist year‐round. To overcome the challenge of detecting and localising different host species, it is proposed that frog‐biting midges have evolved a generalised acoustic template, allowing them to respond to a broad range of available hosts, regardless of seasonal host composition.     

Diversity,dynamics and reproduction in a community of small mammals in Upper Guinea,with emphasis on pygmy mice ecology

As part of a large survey on reservoirs of Lassa fever in Guinea, three villages were investigated in high endemic zone, close to Sierra Leone border. Biodiversity of the small mammal community is presented in this study through a standardized trapping in houses, cultivations and forest. Identification of the small mammals was based on morphology and by molecular technique for sibling species. Of the 1123 specimens collected in 2003–2005, we identified seventeen species (thirteen Muridae, four Soricidae), leading to high diversity (Shannon index = 1.6–1.8) and high equitability (evenness index = 0.7–0.8) in cultivations and forest. In houses conversely, the rodent community was dominated by Mastomys natalensis (95–98%), leading to low diversity and equitability. Dynamics and reproduction were investigated in two species of pygmy mice, Mus mattheyi and Mus minutoides, two species of Praomys, P. daltoni and P. rostratus, and in Mastomys erythroleucus. The pygmy mice were abundant in cultivations in early rainy season, and reproduced from rainy to dry season. Praomys daltoni was also found more abundant in cultivations and seemed to reproduce between rainy and dry season, whereas P. rostratus preferred forest and cultivations in late rainy season, and reproduced throughout the year. Finally, M. erythroleucus was more abundant in forest in dry season, and seemed to reproduce from late rainy to dry season. This species had a low occurrence (6.5%) in the Faranah’s zone, and probably lived at its southern limit in Guinea. The presence of other Murinae, such as M. natalensis, Praomys spp as possible competitors in the same habitats, is discussed. For the first time, this study relates population biology of pygmy mice with molecular identification.     

Nitrogen enrichment during decomposition of mangrove leaf litter in an east African coastal lagoon (Kenya): Relative importance of biological nitrogen fixation

In situ decomposition of senescent leaves of twoabundant mangrove species (Rhizophora mucronataLamarck and Ceriops tagal (Perr) C.B. Rob),enrichment of nitrogen and activity of dinitrogenfixing bacteria during decomposition were investigatedduring both rainy and dry seasons in a tropicalcoastal lagoon (Gazi, Kenya). Rates of leafdecomposition were higher for R. mucronata thanfor C. tagal and were highest, for both species,during rainy season. Rates of decomposition, expressedas percentage dry mass loss, over a decompositionperiod of 50 days was: C. tagal (rainy season),69%; C. tagal (dry season), 27%; R.mucronata (rainy season), 98%; and R.mucronata (dry season), 48%. High rainfall anddiurnal tidal inundation appear to enhance the leafdecomposition process. Maximum rates of nitrogenfixation were 380 nmol N₂ h^-1 g^-1 dw forC. tagal (rainy season), 78 nmolN₂ h^-1 g^-1 dw for C. tagal (dryseason), 390 nmol N₂ h^-1 g^-1 dw for R. mucronata (rainy season) and 189 nmolN₂ h^-1 g^-1 dw for R. mucronata (dry season). Although N₂ fixation rates werehighest during rainy season, total nitrogenimmobilised in the leaves was highest during the dryseason. Biological nitrogen fixation can account forbetween 13 to 21% of the maximum nitrogen immobilisedin the decaying mangrove leaves. Nitrogen fixation, asa source of allochthonous nitrogen, sustains anitrogen input to the mangrove ecosystem, which addssignificantly to the nitrogen input through leaflitterfall.     

Effect of Air Humidity on the Egg Viability of Predatory Mites (Acari: Phytoseiidae, Stigmaeidae) Common on Rubber Trees in Brazil

Rubber pest mites, Calacarus heveae and Tenuipalpus heveae, reach economic damage levels at the end of the rainy season and the beginning of the dry season in Brazil. Therefore, low humidity adaptation might be an important characteristic for predatory mites to successfully control pest organisms. This study determined the effect of the relative humidity (RH) levels of 30–100% on the hatching of larvae of Amblyseius acalyphus, Euseius citrifolius, Iphiseiodes zuluagai, Metaseiulus camelliae, Agistemus floridanus and Zetzellia malvinae at 25 ± 0.5 °C. These predatory mites are common on rubber trees in the state of São Paulo and might be used for introduction in the major rubber tree production regions in the state of Mato Grosso. At 70% RH or higher, viability was 70% or higher for all species, indicating that their performance might be higher during the rainy season than during the dry season. Eggs of E. citrifolius and M. camelliae presented higher viability at the lower relative humidity levels than those of other species, indicating that these species might have higher chance to persist in the dry season. It is suggested that M. camelliae should be further evaluated for introduction in the state of Mato Grosso, considering that this mite is not yet present in that area.     

Nest relocation and high mortality rate in a Neotropical social wasp: Impact of an exceptionally rainy La Niña year

After noting the forecast of a La Niña episode, associated with heavy rainfall in French Guiana, we monitored the fate of wasp nests before and during the 2006 short rainy season. The population of the most abundant epiponine wasp species, Polybia bistriata, decreased dramatically during the short rainy season (60.6% of the nests disappeared) then remained low for at least 18 months. Colonies that survived moved from the shelter of large, low leaves (a situation well adapted to the previous dry season) of the most frequent substrate tree, Clusia grandiflora (Clusiaceae), to upper leaves, better ventilated and whose orientation provides good protection from the rain. Therefore, the possibility of moving the nest higher during the first rains following the dry season seems very adaptive as colonies that do not do so are eliminated during the La Niña years, whose frequency will increase with global climate change.     

Mammalian community structure in lowland, tropical Peru, as determined by removal trapping

Amazonian lowland rain forests are complex three-dimensional formations consisting of a variety of arboreal and terrestrial habitats. The small mammal faunas, particularly of arboreal habitats, are poorly studied, and field research generally has been limited to a few faunal inventories. We sampled the terrestrial and arboreal small mammal fauna in two floodplain forest study zones at Reserva Cuzco Amazonico, southeastern Peru, by removal trapping for 12 consecutive days in dry (June-July 1989) and rainy seasons (January-February 1990). Nineteen taxa of marsupials and rodents were captured. Small mammals were more abundant in the rainy season than in the dry season, but the relative proportions of the 11 most abundant species remained stable between seasons and study zones. Most species showed no decline in capture rates through the 12-day period, indicating that either population densities were high or animals were quite mobile. The small mammal fauna exhibited strong vertical stratification; among the 11 most abundant species, four exhibited strong biases toward terrestrial and five toward above-ground captures. The distinct arboreal small mammal community is grossly underrepresented if traps are placed only at ground level.     

Factors affecting searcher efficiency and scavenger removal of bat carcasses in Neotropical wind facilities

Bat fatalities at wind facilities have been reported worldwide, and environmental impact assessments depend on searches for carcasses around wind turbines to quantify impacts. Some of the carcasses may go undetected by search teams or be removed by scavengers during search intervals, so these biases must be evaluated and taken into account in fatality estimation. We investigated the influence of different factors on searcher efficiency and scavenger removal in a dry forest area in northeastern Brazil, one of the regions with the highest density of wind turbines in the Neotropics. We conducted searcher efficiency and scavenger removal trials around 34 wind turbines from January 2017 to January 2018. Searcher efficiency was influenced by cover type, season, and carcass size, ranging between 12% for small bats in shrub vegetation during the rainy season and 96% for large bats in absent or sparse vegetation during the dry season. Carcass type and season affected scavenger removal; carcass persistence time was shorter for chicks (1.2 days) than for bats and mice (2.1 days), and the probability of a carcass persisting for a whole day was higher in the rainy season, while the probability of carcass persistence for 7, 14, and 28 days was higher in the dry season. The scavenger community was composed of canids, birds of prey, and insects, with systematic removal of carcasses by the crab-eating fox (Cerdocyon thous) throughout the year and by dung beetles in the rainy season. Based on our findings, impact assessments of wind facilities on bats should conduct searcher efficiency trials in all seasons and cover types around wind turbines, using bat carcasses or models of different sizes. Scavenger removal trials should cover all seasons as well, and use mouse carcasses (but not chick carcasses) as surrogates for bats.     

亚热带常绿阔叶林6个常见树种凋落叶在不同降雨期的分解特征

地处长江上游的四川盆地亚热带常绿阔叶林具有典型雨热同季的气候特点,季节性干湿交替可能显著影响凋落物分解,但迄今缺乏相应的报道。因此,采用凋落物分解袋法,研究了常绿阔叶林区最具代表性的马尾松(Pinus massoniana)、柳杉(Cryptomeria fortunei)、杉木(Cunninghamia lanceolata)、香樟(Cinnamomum camphora)、红椿(Toona ciliata)、麻栎(Quercus acutissima)等6种凋落叶在第1年不同雨热季节的分解特征。结果表明,经历1a的分解,6种凋落叶质量残留率大小顺序依次为:红椿(27.90%)柳杉(41.39%)杉木(48.93%)麻栎(49.62%)马尾松(68.82%)香樟(72.23%),6种凋落叶在不同干湿季节质量损失差异显著(P0.05)。阔叶树种在旱季(MRS、SRS和WRS)的质量损失显著高于针叶树种。雨季(ERS和LRS)对6种凋落叶质量损失的贡献率(69.73%—89.68%)均明显大于旱季(10.32%—30.27%)。6种凋落叶在不同时期中质量损失速率差异显著(P0.05),且6种凋落叶在雨季的质量损失速率明显高于旱季。相关分析结果表明,凋落叶质量损失及其速率均与降雨量和温度呈极显著(P0.01)正相关关系。凋落叶质量损失与初始C、木质素含量及C/N、木质素/N极显著(P0.01)负相关,与N含量极显著(P0.01)正相关。这些结果表明亚热带地区森林凋落物分解的质量损失主要发生在雨季,雨季温湿度的改变可显著影响凋落物分解过程。     

Diet of Physalaemus cf. cicada (Leptodactylidae) and Bufo granulosus (Bufonidae) in a semideciduous forest.

We determined the diet of the two most abundant anuran species which occur in the litter of a semideciduous forest (Len?óis, Bahia, Brazil), Physalaemus cf. cicada and Bufo granulosus in the dry and rainy seasons. Pitfall traps were used to collect anuran and invertebrate fauna, which showed the availability of prey in the environment. Physalaemus cf. cicada was present in both seasons and Bufo granulosus only in the rainy season. Both species fed mainly on Isoptera and Formicidae. However, there is a difference between the rainy and dry seasons concerning the diet of P. cf. cicada. During the rainy season P. cf. cicada consumed less Isoptera and more Formicidae than in the dry season. In the volumetric sense, Orthoptera was the most important alimentary category for P. cf. cicada and B. granulosus. The Jacobs electivity index indicated that Physalaemus cf. cicada and Bufo granulosus were specialists in Isoptera.     

Wastewater Irrigation Increases the Abundance of Potentially Harmful Gammaproteobacteria in Soils in Mezquital Valley,Mexico

Wastewater contains large amounts of pharmaceuticals, pathogens, and antimicrobial resistance determinants. Only a little is known about the dissemination of resistance determinants and changes in soil microbial communities affected by wastewater irrigation. Community DNAs from Mezquital Valley soils under irrigation with untreated wastewater for 0 to 100 years were analyzed by quantitative real-time PCR for the presence of sul genes, encoding resistance to sulfonamides. Amplicon sequencing of bacterial 16S rRNA genes from community DNAs from soils irrigated for 0, 8, 10, 85, and 100 years was performed and revealed a 14% increase of the relative abundance of Proteobacteria in rainy season soils and a 26.7% increase in dry season soils for soils irrigated for 100 years with wastewater. In particular, Gammaproteobacteria, including potential pathogens, such as Pseudomonas, Stenotrophomonas, and Acinetobacter spp., were found in wastewater-irrigated fields. 16S rRNA gene sequencing of 96 isolates from soils irrigated with wastewater for 100 years (48 from dry and 48 from rainy season soils) revealed that 46% were affiliated with the Gammaproteobacteria (mainly potentially pathogenic Stenotrophomonas strains) and 50% with the Bacilli, whereas all 96 isolates from rain-fed soils (48 from dry and 48 from rainy season soils) were affiliated with the Bacilli. Up to six types of antibiotic resistance were found in isolates from wastewater-irrigated soils; sulfamethoxazole resistance was the most abundant (33.3% of the isolates), followed by oxacillin resistance (21.9% of the isolates). In summary, we detected an increase of potentially harmful bacteria and a larger incidence of resistance determinants in wastewater-irrigated soils, which might result in health risks for farm workers and consumers of wastewater-irrigated crops.