Genome and cuticular hydrocarbon‐based species delimitation shed light on potential drivers of speciation in a Neotropical ant species complex

Geographic separation that leads to the evolution of reproductive isolation between populations generally is considered the most common form of speciation. However, speciation may also occur in the absence of geographic barriers due to phenotypic and genotypic factors such as chemical cue divergence, mating signal divergence, and mitonuclear conflict. Here, we performed an integrative study based on two genome‐wide techniques (3RAD and ultraconserved elements) coupled with cuticular hydrocarbon (CHC) and mitochondrial (mt) DNA sequence data, to assess the species limits within the Ectatomma ruidum species complex, a widespread and conspicuous group of Neotropical ants for which heteroplasmy (i.e., presence of multiple mtDNA variants in an individual) has been recently discovered in some populations from southeast Mexico. Our analyses indicate the existence of at least five distinct species in this complex: two widely distributed across the Neotropics, and three that are restricted to southeast Mexico and that apparently have high levels of heteroplasmy. We found that species boundaries in the complex did not coincide with geographic barriers. We therefore consider possible roles of alternative drivers that may have promoted the observed patterns of speciation, including mitonuclear incompatibility, CHC differentiation, and colony structure. Our study highlights the importance of simultaneously assessing different sources of evidence to disentangle the species limits of taxa with complicated evolutionary histories.     

Potential Non-target Effects of a Biological Control Agent, Prickly Pear Moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), in North America, and Possible Management Actions

Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), the poster child of biological control, has recently invaded the United States. The first US record was at Big Pine Key, Florida, in 1989. Since then it has moved rapidly northward into South Carolina. Fears are high that it will disperse, either on its own, or with human help, into the US desert southwest and Mexico. There are at least 31 species of prickly pear in the US that are likely to be attacked by Cactoblastis and 56 species in Mexico. As well as the threat to wild cacti, there are over 250,000 ha of Opuntia plantations in Mexico that support a thriving agricultural industry, most of which is centered on harvesting fruits or pads. Possible control measures include classical biological control using parasitoids or pathogens from South America, chemical control or F₁ sterility, as has been used successfully for the codling moth. However, most of these options appear to have insurmountable difficulties. Classical biological control raises the fear of further non-target effects of natural enemies on native cactus herbivores. Chemical control has potential non-target effects on other (rare) insects and is expensive. F₁ sterility is also expensive and is not self-sustaining, requiring considerable and continual human input. Nevertheless, research on control options is vital as is further work on the rate of spread and impact of Cactoblastis in the United States Southeast, so that we can be as well prepared as possible to deal with this threat when it arrives in Arizona, California, and Mexico.     

Restoration of Gibberellin Production in Fusarium proliferatum by Functional Complementation of Enzymatic Blocks

Nine biological species, or mating populations (MPs), denoted by letters A to I, and at least 29 anamorphic Fusarium species have been identified within the Gibberella fujikuroi species complex. Members of this species complex are the only species of the genus Fusarium that contain the gibberellin (GA) biosynthetic gene cluster or at least parts of it. However, the ability of fusaria to produce GAs is so far restricted to Fusarium fujikuroi, although at least six other MPs contain all the genes of the GA biosynthetic gene cluster. Members of Fusarium proliferatum, the closest related species, have lost the ability to produce GAs as a result of the accumulation of several mutations in the coding and 5′ noncoding regions of genes P450-4 and P450-1, both encoding cytochrome P450 monooxygenases, resulting in metabolic blocks at the early stages of GA biosynthesis. In this study, we have determined additional enzymatic blocks at the first specific steps in the GA biosynthesis pathway of F. proliferatum: the synthesis of geranylgeranyl diphosphate and the synthesis of ent-kaurene. Complementation of these enzymatic blocks by transferring the corresponding genes from GA-producing F. fujikuroi to F. proliferatum resulted in the restoration of GA production. We discuss the reasons for Fusarium species outside the G. fujikuroi species complex having no GA biosynthetic genes, whereas species distantly related to Fusarium, e.g., Sphaceloma spp. and Phaeosphaeria spp., produce GAs.     

The genus Juniperus in Mexico and Guatemala: Numerical and chemosystematic analysis

The variation leaf constituents (mostly terpenoids) was analyzed from each of the taxa of Juniperus in Mexico and Guatemala by numerical taxonomic methods. These results were compared with those of a previous study utilizing morphological characters. In general, the two agree on the major groups. Differences between more closely related species were more apparent with the chemical data, whereas more distantly related taxa sometimes appeared to be more closely related chemically due to the presence of a single component such as α-pinene in high concentration in each of the oils. Four large groups are apparent; the deppeanan; flaccidan; monticolan; and the oneseeded (pinchotii) complex. Some taxa (J. durangensis, J. standleyi, J.jaliscana) are still of uncertain affinities. This study confirms the morphological data indicating that J. patoniana Martínez should be reduced to a variety of J. deppeana (J. deppeana var. patoniana (Martínez) Zanoni, comb. et stat. nov). No samplestypical of J. monosperma were found in Mexico and J. monosperma var. gracilis (sensu Martinez) was found to not be closely allied with J. monosperma from the USA but has some uncertain affinities with species of the one-seeded complex. These relationships need to be examined in more detail. J. blancoi appears to be closely related to J. scopulorum. This information on the junipers of Mexico and Guatemala should prove invaluable to future studies on the evolution of the Juniperus in North America.     

Two Distinct Triatoma dimidiata (Latreille, 1811) Taxa Are Found in Sympatry in Guatemala and Mexico

Approximately 10 million people are infected with Trypanosoma cruzi, the causative agent of Chagas disease, which remains the most serious parasitic disease in the Americas. Most people are infected via triatomine vectors. Transmission has been largely halted in South America in areas with predominantly domestic vectors. However, one of the main Chagas vectors in Mesoamerica, Triatoma dimidiata, poses special challenges to control due to its diversity across its large geographic range (from Mexico into northern South America), and peridomestic and sylvatic populations that repopulate houses following pesticide treatment. Recent evidence suggests T. dimidiata may be a complex of species, perhaps including cryptic species; taxonomic ambiguity which confounds control. The nuclear sequence of the internal transcribed spacer 2 (ITS2) of the ribosomal DNA and the mitochondrial cytochrome b (mt cyt b) gene were used to analyze the taxonomy of T. dimidiata from southern Mexico throughout Central America. ITS2 sequence divides T. dimidiata into four taxa. The first three are found mostly localized to specific geographic regions with some overlap: (1) southern Mexico and Guatemala (Group 2); (2) Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica (Group 1A); (3) and Panama (Group 1B). We extend ITS2 Group 1A south into Costa Rica, Group 2 into southern Guatemala and show the first information on isolates in Belize, identifying Groups 2 and 3 in that country. The fourth group (Group 3), a potential cryptic species, is dispersed across parts of Mexico, Guatemala, and Belize. We show it exists in sympatry with other groups in Peten, Guatemala, and Yucatan, Mexico. Mitochondrial cyt b data supports this putative cryptic species in sympatry with others. However, unlike the clear distinction of the remaining groups by ITS2, the remaining groups are not separated by mt cyt b. This work contributes to an understanding of the taxonomy and population subdivision of T. dimidiata, essential for designing effective control strategies.     

Rediscovery of Polypodium calirhiza (Polypodiaceae) in Mexico

This study addresses reported discrepancies regarding the occurrence of Polypodium calirhiza in Mexico. The original paper describing this taxon cited collections from Mexico, but the species was omitted from the recent Pteridophytes of Mexico. Originally treated as a tetraploid cytotype of P. californicum, P. calirhiza now is hypothesized to have arisen through hybridization between P. glycyrrhiza and P. californicum. The tetraploid can be difficult to distinguish from either of its putative parents, but especially so from P. californicum. Our analyses show that a combination of spore length and abaxial rachis scale morphology consistently distinguishes P. calirhiza from P. californicum, and we confirm that both species occur in Mexico. Although occasionally found growing together in the United States, the two species are strongly allopatric in Mexico: P. californicum is restricted to coastal regions of the Baja California peninsula and neighboring Pacific islands, whereas P. calirhiza grows at high elevations in central and southern Mexico. The occurrence of P. calirhiza in Oaxaca, Mexico, marks the southernmost extent of the P. vulgare complex in the Western Hemisphere.     

The Phytophagous Arthropods Associated with Senna obtusifolia (Caesalpiniaceae) in Mexico and Honduras and Their Prospects for Utilization for Biological Control

A survey of the phytophagous arthropod fauna associated with sicklepod, Senna obtusifolia, was undertaken between 1991 and 1993 to find biological control agents for this increasingly serious weed in Australia and its closely related congener, Senna tora. The survey concentrated in Mexico on the Gulf coast, the Pacific coast, and the Yucatan peninsula. Additional searching was undertaken in the state of Morelos, Mexico and Honduras. Some 108 phytophagous insect species were found. Literature searches and preliminary observation indicated that 10 species were sufficiently stenophagous to warrant further consideration as potential biocontrol agents. Two species, Mitrapsylla albalineata (Homoptera: Psyllidae) and Conotrachelus sp. ‘Morelos’ (Coleoptera: Curculionidae), have been brought to Australia for further study.     

Molecular Standardization of Mating Type Terminology in the Gibberella fujikuroi Species Complex

Mating type in the Gibberella fujikuroi species complex is controlled by a single locus with two alleles and is usually identified following sexual crosses with standard, female-fertile tester isolates. The mating type alleles have been arbitrarily designated “+” and “−” within each biological species, and the nomenclature is tied to the standard tester strains. We developed a pair of PCR primers that can be used to amplify a unique fragment of one of the mating type alleles (MAT-2) from at least seven of the biological species in this species complex. Based on the amplification pattern, we propose a replacement for the existing, arbitrary +/− terminology that is presently in use. The new terminology is based on DNA sequence similarities between the mating type allele fragments from the biological species of the G. fujikuroi species complex and the corresponding fragments from other filamentous ascomycetes.     

The Opuntia (Cactaceae) and Dactylopius (Hemiptera: Dactylopiidae) in Mexico: a historical perspective of use, interaction and distribution

A historical perspective on the use and production of species of Dactylopius (Hemipetera: Dactylopiidae) and Opuntia (Cactaceae: Opuntioidae), information on their origin, diversity and distribution in Mexico are reviewed, and aspects of their conservation are discussed. The use and exploitation of both genera are part of Mexican cultures since prehistory. Opuntia species were among the main components of human diet during pre-agricultural times. Cochineal was used and probably cultivated at least from the Tenth century. During the colonial period, cochineal generated significant benefits to the Spaniard colonizers and Mexico was the world’s first producer of insects and dyes until the mid Nineteenth century. Currently, Mexico is the main producer of Opuntia cladodes and prickly pear, but cochineal cultivation is marginal and only maintained in traditional indigenous systems. Mexico is one of the main areas of diversity of Opuntia, having 83–104 out of nearly 200 species worldwide. More than 50 species are used mainly as food, fodder and medicine and 20 species are cultivated with different degrees of domestication. The genus Dactylopius includes nine species, with five of them naturally occurring in Mexico. Only D. coccus has been cultivated and domesticated but other wild species have been used throughout history. Arid and semiarid areas of Mexico are among the most important reservoirs of biological diversity for both genera, particularly for D. coccus. Specific measures for protection of such biodiversity and generic resources are required. Strategies for in situ conservation combined with re-established use and cochineal production may enhance conservation policies.     

Description of a New Species of Neoadoxoplatys and Immature Stages of Neoadoxoplatys saileri Kormilev (Heteroptera: Pentatomidae) Associated with Bamboo

Neoadoxoplatys thomasi is described as a new species from Mexico and Venezuela. The immature stages of Neoadoxoplatys saileri Kormilev are presented for the first time. Immature stages are described and illustrated, some bamboo species of Guadua are recorded as hosts, distributional records in Mexico are also included; scanning electron micrographs of the eggs of N. saileri are provided. A key to separate the four known species of Neoadoxoplatys is included.     

First Molecular Characterization of Colletotrichum sp. and Fusarium sp. Isolated from Mangrove in Mexico and the Antagonist Effect of Trichoderma harzianum as an Effective Biocontrol Agent

The aim of this study was to characterize potential fungal species affecting mangrove species in Mexico. The phytopathogens were identified based on morphological and molecular characteristics using internal transcribed spacer (ITS1/ITS4) primers then sequenced and compared with the other related sequences in GenBank (NCBI). Three fungal species were identified as Colletotrichum queenslandicum (Weir and Johnst, 2012) from black mangrove (Avicennia germinans); Colletotrichum ti (Weir and Johnst, 2012) from white mangrove (Laguncularia racemosa) and buttonwood mangrove (Conocarpus erectus); Fusarium equiseti (Corda) from red mangrove (Rhizophora mangle). In addition, C. ti and F. equiseti were identified from mango Mangifera indica L. sampled close by the mangrove area. This study provides first evidence of anthracnose on four mangrove species caused by Colletotrichum and Fusarium species in the “Términos” coastal lagoon in Campeche State southern Mexico. This is the first time that C. queenslandicum and C. ti are reported in Mexico. F. equiseti has not been reported affecting M. indica and R. mangle until the present work. Little is known regarding fungal diseases affecting mangroves in Mexico. These ecosystems are protected by Mexican laws and may be threatened by these pathogenic fungus. This is the first report of the effect of Trichoderma harzianum TRICHO-SIN as an effective biological control against of Colletotrichum and Fusarium species.     

Transatlantic disjunction in fleshy fungi. I. The Sparassis crispa complex

Phylogenies based on ITS and LSU sequences show that the Sparassis crispa complex comprises several monophyletic clades, in some cases co\rresponding to named taxa (i.e. S. crispa, S. radicata), but others lacking names (i.e. eastern and southwestern North American S. “crispa”). In our study, morphological examination of numerous collections also distinguished subtle differences correlated with geographic distribution. Underlying these problems, several taxa lacked type specimens for taxonomic analysis. In this paper, appropriate epitypes are designated and names assigned. Extensive sexual compatibility experiments, described within, indicate that monokaryon, haploid isolates of collections from North America and Europe are consistently sexually compatible to some degree. Inherent in the study, different “species concepts” were tested, with the “biological species concept,” based on sexual compatibility, being the least restrictive. We propose two new taxa, S. americana and S. americana f. arizonica.     

Species Distribution and Population Connectivity of Deep-Sea Mussels at Hydrocarbon Seeps in the Gulf of Mexico

Hydrocarbon seepage is widespread and patchy in the Gulf of Mexico, and six species of symbiont containing bathymodiolin mussels are found on active seeps over wide and overlapping depth and geographic ranges. We use mitochondrial genes to discriminate among the previously known and a newly discovered species and to assess the connectivity among populations of the same species in the northern Gulf of Mexico (GoM). Our results generally validate the morphologically based distribution of the three previously known GoM species of Bathymodiolus, although we found that approximately 10% of the morphologically based identifications were incorrect and this resulted in some inaccuracies with respect to their previously assigned depth and geographical distribution patterns. These data allowed us to confirm that sympatry of two species of Bathymodiolus within a single patch of mussels is common. A new species of bathymodiolin, Bathymodiolus sp. nov., closely related to B. heckerae was also discovered. The two species live at the same depths but have not been found in sympatry and both have small effective population sizes. We found evidence for genetic structure within populations of the three species of Bathymodiolinae for which we had samples from multiple sites and suggest limited connectivity for populations at some sites. Despite relatively small sample sizes, genetic diversity indices suggest the largest population sizes for B. childressi and Tamu fisheri and the smallest for B. heckerae and B. sp. nov. among the GoM bathymodiolins. Moreover, we detected an excess of rare variants indicating recent demographic changes and population expansions for the four species of bathymodiolins from the Gulf of Mexico.     

Wild Mushroom Markets in Central Mexico and a Case Study at Ozumba

Wild Mushroom Markets in Central Mexico and a Case Study at Ozumba. More than 200 species of wild edible mushrooms are consumed in Mexico, and over 100 are sold in local, regional, and wholesale markets. This paper analyzes general trends in the commercialization of wild edible mushrooms at twelve markets in central Mexico, where at least 90 species are sold and more than 100 local names were registered. The paper then focuses its analysis on the traditional market at Ozumba (state of Mexico) near Izta-Popo and Zoquiapan national parks. In 2006, 411 stands selling more than 60 mushroom species were sampled throughout the year to record information on the vendors and the species they sold. The greatest diversity of species was recorded in July and August. More than 90% of the wild mushroom vendors were women, and 64% were 40 to 60 years old. The economic value of wild mushrooms in some regions of Mexico appears to contribute to the maintenance of traditional ethnobiological knowledge, generally observed to be in overall decline.     

Morphological and molecular identification of helminths of the greater bulldog bat Noctilio leporinus (Quiroptera: Noctilionidae) from Campeche,Mexico

Surveys on parasites of bats from the Americas have been conducted, but information on helminths is still scarce, especially in the Neotropical region. In Mexico, there are species of bats that lack of a record for helminth species, such as members of the family Noctilionidae. The present study describes for the first time the helminths of Noctilio leporinus in Campeche, Mexico. In 2017, six specimens of N. leporinus were studied for helminths. The species identification of helminths was based on morphological studies and molecular analysis of fragments of the 28S rDNA. All bat specimens were infected for at least one helminth species. Three helminth taxa were identified: the trematode Pygidiopsis macrostomum, and the nematodes Tricholeiperia cf. proencai, and Heligmonellidae gen. sp. The morphological identification of P. macrostomum was confirmed by sequence analysis of 28S rDNA gene. The phylogeny of P. macrostomum grouped our sequence with other sequences of the same species collected in Brazil. The phylogenetic tree of Heligmonellidae gen. sp. indicated that the helminth belongs to clade formed by the species Odilia bainae, Nippostrongylus magnus and Nippostrongylus brasiliensis of the family Heligmonellidae. The phylogenetic analysis of the 28S sequences of T. cf. proencai did not show any similarity or close affinity with nematodes from which that gene has been sequenced to date. The findings of the present study increase the number of helminth species parasitizing bats in Mexico.     

A biometric and ecologic comparison between Artemia from Mexico and Chile

Background

A preliminary biometric and ecologic database for the brine shrimp Artemia from Mexico and Chile is presented. The area abounds in small and seasonal ponds and large inland lakes, the latter mainly located in Mexico, although relatively large and isolated lakes are found in complex hydrological settings in pre-high plateau areas of Chile. This paper summarizes research efforts aimed at the localization, characterization, and evaluation of the aquaculture potential of Artemia populations in Mexico and Chile, which exhibit great habitat diversity (ponds, salterns, coastal lagoons, sea arms, coastal and inland lakes), contrasting weather conditions and different levels of isolation and human intervention.

Results

This study covered locations between 29° north latitude (Baja California, Mexico) to 50° south latitude (Puerto Natales, Chile). Biological characteristics considered are species name, reproductive mode, cyst diameter, chorion thickness, and nauplius length, whereas ecological data include pond size, pH, salinity, temperature, and water ionic composition. Artemia franciscana is the only species found in Mexico, it exists together with A. persimilis in Chile, though separated geographically. Ecological differences in habitat exist between both regions but also within countries, a pattern particularly clear with regard to water composition. Surprisingly, a Mexican (Cuatro Ciénegas, A. franciscana) and a Chilean location (Torres del Paine, A. persimilis) share habitat characteristics, at least for the period when data were collected. The discriminat analysis for cyst diameter and nauplius length shows that Artemia from only one location match in cyst diameter with those from San Francisco Bay (SFB) (Point Lobos), and one (Marquez) is far apart from SFB and all the others. The Chilean locations (Pampilla, Cejar, Cahuil, Llamara, Yape) share cyst diameter, but tend to differ from SFB. The remaining Mexican locations (Juchitan, Ohuira, Yavaros) are well separated from all the others. With regard to nauplii length, populations tend to distribute in a relatively random manner, being Marquez the location differing the most in cyst diameter from SFB.

Conclusion

This database will contribute to the knowledge of radiation centers and serves as a baseline for further biogeographic studies, population characterization, management, and monitoring of Artemia biodiversity. Likewise, the impact of colonization and translocations for aquaculture purposes can be better assessed with a baseline for reference. Mexico and Chile exemplify the need to increase and further integrate regional information to tackle fundamental problems underlying practical utilization of Artemia.     

Physiological response of 10 phytoplankton species exposed to macondo oil and the dispersant,Corexit

Culture experiments were conducted on ten phytoplankton species to examine their biological and physiological responses during exposure to oil and a combination of oil and dispersant. The species tested included a range of taxa typically found in the Gulf of Mexico such as cyanobacteria, chlorophytes, and diatoms. Cultures were exposed to Macondo surrogate oil using the water accommodated fraction (WAF), and dispersed oil using a chemically enhanced WAF (CEWAF) and diluted CEWAF, to replicate conditions following the Deepwater Horizon spill in the Gulf of Mexico. A range of responses were observed, that could broadly class the algae as either “robust” or “sensitive” to oil and/or dispersant exposure. Robust algae were identified as Synechococcus elongatus, Dunaliella tertiolecta, two pennate diatoms Phaeodactylum tricornutum and Navicula sp., and Skeletonema grethae CCMP775, and were largely unaffected by any of the treatments (no changes to growth rate or time spent in lag phase relative to controls). The rest of the phytoplankton, all centric diatoms, exhibited at least some combination of reduced growth rates or increased lag time in response to oil and/or dispersant exposure. Photophysiology did not have a strong treatment effect, with significant inhibition of photosynthetic efficiency (F_v/F_m) only observed in the CEWAF, if at all. We found that the effects of oil and dispersants on phytoplankton physiology were species‐dependent, and not always detrimental. This has significant implications on how oil spills might impact phytoplankton community structure and bloom dynamics in the Gulf of Mexico, which in turn impacts higher trophic levels.     

Wolbachia strains in cryptic species of the Anastrepha fraterculus complex (Diptera,Tephritidae) along the Neotropical Region

Infection by Wolbachia was described previously in eleven species of Anastrepha fruit flies some of which are important pests of fruticulture. One such species is the nominal Anastrepha fraterculus, the South American fruit fly, which actually comprises a complex of cryptic species. The suggestions of using Wolbachia for the control of these pest species, make imperative a more precise characterization of the existing strains of the bacteria. In this study, population samples of the A. fraterculus complex from Brazil, Argentina, Peru, Ecuador, Colombia, Guatemala and Mexico were analyzed for Wolbachia infection. The bacteria were genotyped by the MLST and WSP Typing methodologies. All samples were infected with Wolbachia of supergroup “A”. For each of the five MLST genes, unique as well as already known alleles were detected. Nineteen sequence types for the concatenated sequences of the five MLST genes, and twenty wsp alleles were found in the samples. Host-specific haplotypes, shared strains among distinct hosts, and more than one strain of Wolbachia were found in some population samples. Recombination among the MLST genes and intragenic recombination between wsp haplotypes was rare. Phylogenetic analysis showed a great similarity among the Wolbachia strains in the A. fraterculus complex. However, some strains of Wolbachia are found throughout the Neotropical Region and there are specific strains in determined geographical areas.     

Evolutionary History of the Live-Bearing Endemic Allotoca diazi Species Complex (Actinopterygii,Goodeinae): Evidence of Founder Effect Events in the Mexican Pre-Hispanic Period

The evolutionary history of Mexican ichthyofauna has been strongly linked to natural events, and the impact of pre-Hispanic cultures is little known. The live-bearing fish species Allotoca diazi, Allotoca meeki and Allotoca catarinae occur in areas of biological, cultural and economic importance in central Mexico: Pátzcuaro basin, Zirahuén basin, and the Cupatitzio River, respectively. The species are closely related genetically and morphologically, and hypotheses have attempted to explain their systematics and biogeography. Mitochondrial DNA and microsatellite markers were used to investigate the evolutionary history of the complex. The species complex shows minimal genetic differentiation. The separation of A. diazi and A. meeki was dated to 400–7000 years ago, explained by geological and climate events. A bottleneck and reduction of genetic diversity in Allotoca diazi was detected, attributed to recent climate fluctuations and anthropogenic activity. The isolation of A. catarinae occurred ~1900 years ago. No geological events are documented in the area during this period, but the date is contemporary with P’urhépecha culture settlements. This founder effect represents the first evidence of fish species translocation by a pre-Hispanic culture of Mexico. The response of the complex to climate fluctuation, geological changes and human activity in the past and the future according to the ecological niches predictions indicates areas of vulnerability and important information for conservation. The new genetic information showed that the Allotoca diazi complex consist of two genetic groups with an incomplete lineage sorting pattern: Pátzcuaro and Zirahuén lakes, and an introduced population in the Cupatitzio River.