The Ecitoninae ants (Hymenoptera: Formicidae) from Morelos, México

To produce an inventory of the Ecitoninae ants from Morelos State (south central Mexico), we used direct capture and pit-fall traps. Occasionally, males were also collected near artificial light sources. Fifteen species were found: Labidus coecus, L. praedator s. str, Neivamyrmex agilis, N. cornutus, N fallax, N. graciellae, N. impudens, N. macropterus, N. melanocephalus, N. nigrescens, N. opacithorax, N. pauxilus, N. sumichrasti, N. swainsoni and Nomamyrmex esenbecki mordax. Twelve of these species are new records for the state. The most abundant species were L. coecus, N. melanocephalus, N. nigrescens and N. esenbecki mordax. The distribution of the species in the state, flight dates of males for some species, and a key for the identification of workers and males are included. One additional species (N. fuscipennis), collected by other authors in Morelos but not by us, is also included in the key.     

Native vegetation structure and persistence of endangered Tehuantepec jackrabbits in a neotropical savanna in Oaxaca, México

Because of its crucial importance for the persistence of the endangered Tehuantepec jackrabbit (Lepus flavigularis), we identified structural characteristics of native vegetation (1) selected by Tehuantepec jackrabbits to establish home ranges, (2) used within home ranges, and (3) in relation to activity and inactivity periods. A neotropical savanna in the Isthmus of Tehuantepec, Oaxaca, México, offered diversity in native flora and heterogeneity in vegetation structure to the studied population of Tehuantepec jackrabbit. Adults and juveniles differed in habitat use patterns. No effect on habitat selection was detected for sex or season. Jackrabbits established home ranges on grassy habitat with discontinuous overstory of nanche (Byrsonima crassifolia) shrubbery and morro (Crescentia) trees. Adults underused dense vegetation where predators may ambush them; juveniles avoided dense vegetation and grassland without overstory. Within adults’ home ranges, habitat selection favoring grassy habitats with nanche and morro was relatively stronger during the activity period (nocturnal and crepuscular hours) and during one of 2 years which had more rainfall. Scattered trees and open shrubbery likely allowed foraging jackrabbits with both visibility and escape routes used to detect and outrun predators. Moreover, during the inactivity period (diurnal hours) adults and juveniles favored nanche shrubbery that provided resting jackrabbits with shelter to hide from predators. Clearly, structure and diversity of native vegetation in the savanna needs to be preserved for conservation of Tehuantepec jackrabbits because deteriorated habitat may pose higher predation rates for a jackrabbit population in risk of extirpation.     

Frequency of antibodies to Toxoplasma gondii in stray dogs of Oaxaca, México

We studied the frequency of antibodies against Toxoplasma gondii in stray dogs in the city of Oaxaca, Mexico through the evaluation of 154 sera by indirect ELISA. A frequency of 61.7% was found; it was higher in males (45 of 65, 69.2%) than in females (49 of 89, 55.0%), although this difference was not statistically significant. An increase in frequency was observed with age, the lowest being among animals younger than 1 yr (4 of 20, 20.0%) and the highest in dogs older than 7 yr (21 of 25, 84.0%). This is the first study in dogs of this region of Mexico and revealed high T. gondii transmission and evidence of early exposure in animals that are in close contact with contaminated water or raw meat, or both. Further studies are needed in order to understand the role of T. gondii infection in public health.     

The vertical distribution and abundance of gastropods and bivalves from rocky beaches of Cuastecomate Bay, Jalisco, México

The vertical distribution and abundance of conspicuous gastropod and bivalve species were studied at five rocky beaches in Cuastecomate Bay, Jalisco. Sampling was done from September, 1993 through March, 1994 with 0.75 m2 quadrants placed along replicate transect lines (10 m long) in the supralittoral and mesolittoral (upper, middle and lower intertidal) zones. A total of 6,643 mollusks were collected. Gastropods dominated the samples (6,272 individuals, 44 species); the bivalves were less abundant and diverse (371 individuals, five species). Seventeen species comprised 89.8% of all individuals collected. The gastropods Nodilittorina aspera and Nerita scabricosta were the most abundant with 637.8 and 71.43 individuals/m2, respectively. The most abundant bivalves were Brachidontes adamsianus and Chloromytilus palliopunctatus with 60.7 and 61.3 individuals/m2 respectively. The abundance of gastropods decreased from the supralittoral to the lower tidal zones while the number of species increased in the same direction. The number of species of bivalves also increased from the supralittoral to the lower intertidal zone; the abundance of individuals was higher at the middle intertidal zone. Affinities between groups of species among sampling stations were identified by computing Pearson's correlation coefficient using abundance values (ind./m2) and Jaccard's dissimilarity index using species presence or absence in the lower intertidal zone. Affinity among stations was not dependent upon their vicinity but on the high dominance of few species, the occurrence of many secondary species and beach characteristics.     

Megapitaria squalida (Bivalvia: Veneridae) fishery landings and temperature relationship in Bahía de la Paz, México

The clam Megapitaria squalida is a fishing resource with increasing importance in Northwestern Mexico. Nevertheless, this fishery has shown important variations that could be related to environmental factors. To assess this, monthly landings of M. squalida were analyzed during 2002-2005 for Bahía de La Paz, B.C.S., and were related with monthly time series of sea surface temperature, derived from MODIS-Aqua Sensor. The results showed a positive and significant relationship between sea surface temperature and clam landings. The likely impact of anomalous conditions of sea temperature on this resource is discussed.     

Ecological observations and biomass proximate composition of the brine shrimp Artemia (Crustacea: Anostraca) from Pichilingue,Baja California Sur,México

The brine shrimp, most probably Artemia franciscana occurs in the solar salt plant (`salina') of Pichilingue (24°15N and 110°20W, total area about 10 ha), Baja California Sur, México. During the periods September 1999 to March 2000 and June 2000 to March 2001, salinity and temperature were determined weekly in selected evaporation ponds, as were the biological parameters of Artemia biomass, size of adult females and males, and monthly the biochemical composition of dried Artemia biomass. An explosive growth of Artemia was observed during moderate salinity levels (80–120 g l^–1), reaching a standing crop level of 300 kg wet weight ha^–1. With increasing salinity, biomass production and the size, especially of the females, decreased drastically, probably due to limited availability of natural food and to environmental stress. Brine shrimp survived up to a salinity of 270 g l^–1. Despite wide variations in the environmental conditions, the proximate analysis of Artemia biomass showed only small differences, with the exception of the crude fibre content.     

Indicators of infestation, colonization and infection of Triatoma dimidiata (Latreille) (Hemiptera: Reduviidae) in Campeche, México

Triatoma dimidiata (Latreille) is considered to be one of the primary vectors of Chagas disease in Southern Mexico and Central America. The objective of the present study was to obtain ecological information on T. dimidiata in two rural communities of Campeche, Mexico, where the vector is poorly studied. Our work consisted of monthly samplings carried out during one-year time at three levels: sylvatic, peridomestic and intradomestic, in order to estimate the population abundance of this species and its rate of infection with Trypanosoma cruzi. Triatoma dimidiata was the unique vector of this disease collected in San Juan Bautista Sakcabchen (SJBS) and Crucero San Luis (CSL). The total of 145 individuals were captured in SJBS; from these, 26.9%, 20% and 53.1% were collected in the sylvatic, peridomestic and intradomestic area, respectively. In CSL captures yielded 108 individuals: 40.7% in the sylvatic area, 20.4% peridomestic and 38.9% intradomestic. We found no correlation between climatic variables and population abundance of T. dimidiata. Dataset obtained suggests that individuals from the sylvatic area exhibit a high rate of natural infection by T. cruzi, with monthly percentages up to 61.5% for SJBS and 50% for CSL. At the peri and intradomestic level, the reservoirs apparently play an important role in the transmission, as the seroprevalence in dogs was 61.5% y 65.4%, for SJBS y CSL, respectively. Based on these findings, it was concluded that inhabitants of both communities are at a high risk of Chagas disease infection.     

Biomass production and nutritional value of Artemia sp. (Anostraca: Artemiidae) in Campeche, México

Biomass of the crustacean Artemia sp. has multiple uses. The biochemical composition and biomass production of Artemia grown from cysts produced by a native population from Real de Salinas were evaluated under laboratory conditions. Nauplii (instar I) were stocked at density of 10 nauplii/ml in 1.5 l tanks, fed with rice bran from day 2 to day 6, and with the microalgae Tetraselmis suecica from day 7 to day 15. At the end of the trial (day 15) the average length was 5.34 mm, biomass production was 15.72 g/l (wet weight), and survival was 79%. The proximal analysis and biochemical composition of Artemia biomass indicated that its nutrient percentages are closely similar to Artemia from other regions, making this species a suitable food for cultured fish and crustacean.     

Monogeneans in introduced and native cichlids in México: evidence for transfer

We examined 2 cichlid fish species native to México, Cichlasoma callolepis and C. fenestratum, and 2 introduced African cichlids, Oreochromis aureus and O. niloticus, from 3 localities in southeastern México for monogeneans. Six monogenean species infected the African cichlids: Cichlidogyrus haplochromii, C. dossoui, C. longicornis longicornis, C. sclerosus, C. tilapiae, and Enterogyrus malmbergi. We found all these parasite species, except C. haplochromii and C. dossoui, on the native C. fenestratum and C. callolepis. Prevalences of Cichlidogyrus spp. were 3-10% and abundances ranged from 0.03 +/- 0.2 to 0.1 +/- 0.3 for native cichlids. We only recovered a single E. malmbergi from 1 C. callolepis. We found Sciadicleithrum bravohollisae, a monogenean of native Cichlasoma spp., on the gills of the introduced O. aureus from Lake Catemaco (prevalence 3%, abundance 0.03 +/- 0.2). Although prevalence and abundance in atypical hosts were fairly low, the present findings provide evidence of monogenean transfer from African to American cichlids and vice versa. This is the first record of exotic monogeneans in the genus Cichlidogyrus and Enterogyrus infecting native American cichlid fish. It is also the first record from southeastern México of a native American monogenean infecting introduced African cichlids.     

Culture of Poecilia reticulata (Pisces: Poecilidae) in tropical water bodies, Veracruz, México

Poecilia reticulata, also known as guppy, is the most popular fish in the aquarium environment. Guppys are viviparous fish with high tolerance to extreme temperatures. The development of the offspring takes between 25 and 30 days. We developed a technology for raising guppys, which outlines infrastructure and devices for reproduction, nursery, feeding, and commercialization, evaluating the financial and technical feasibility of this technology in a case study. The complete reproductive cycle occured in floating cages with 1 mm mesh and the method was tested in a tropical lagoon in Mexico. Water quality was monitored throughout the study period (temperature, dissolved oxygen and pH levels). A marketing survey was carried out at all existing aquarium shops in Veracruz City. Data collected depict quantities demanded and offered for each species by season, place of origin, and resistance to handling. The hydrobiological characteristics were: average temperature 31.4 degrees C, dissolved oxygen 4.5 mgl(-1), and pH level 6.8. With these values we built a production function, and used it to evaluate profitability. We estimate a benefit/cost ratio of 1.16, with a net annual income of US$257.67. The system may provide two permanent jobs.     

Oceanographic conditions and diversity of sea stars (Echinodermata: Asteroidea) in the Gulf of California, México

Species richness is one of the best indicators of biodiversity. However, there are few investigations on concordance of diversity patterns and environmental settings for marine regions. The objectives of this study were to correlate species richness of shallow water (< 200 m deep) sea stars with key oceanographic factors in the Gulf of California, México, and to predict species richness of Asteroidea using multiple regressions. In these analyses the Gulf was divided into nine sections of one degree in latitude (from 23-31 degrees N), at each section we recorded: continental shelf area (at 100 and 200 m depth), temperature mean and range at three depth levels (0, 60 and 120 m), thermocline depth, surface nutrient concentrations (nitrates, phosphates and silicates), surface photosynthetic pigment concentration, and integrated productivity. Sea star species richness at each latitudinal section was estimated from literature data, new collections and museum records. Species were assigned to one of the following feeding guilds: predators of small mobile invertebrates (I), detritivores (D), predators of colonial organisms (C), generalist carnivores (G), and planktivores (P). There are 47 shallow water asteroid species in the Gulf of California (16 I, 15 D, eight C, six G, one P and one not assigned). Total species richness and guild species richness showed strong latitudinal attenuation patterns and were higher in the southernmost Gulf, an area characterized by a narrow shelf, high temperature, and low nutrient concentrations. Species diversity for each guild was correlated to a set of oceanographic parameters: temperature, nitrate concentration, and integrated productivity were linked to richness in must cases. We detected that nutrients and surface pigments always presented negative relationships with species richness, indicating that productive environments limit asteroid diversity in the study area. Finally, the postulated regression models to estimate species richness from oceanographic data were significant and highly precise. We conclude that species richness of Asteroidea in the Gulf of California is related to oceanographic conditions and can be estimated from regional oceanographic information.     

Gelidiaceae (Rhodophyta) in Bahía de Banderas,Western Pacific,México

We present the results of a floristic study of intertidal species of Gelidiaceae collected in ten localities in the Bahía de Banderas region. The study area is within an extensive overlapping transitional zone between the tropical and subtropical regions of the Mexican Pacific coast. Species of the genera Gelidium and Pterocladia were found, G. microdentatum and G. pusillum being the most abundant and widely distributed in the Bay. The local and Mexican Pacific distribution for each species is given. The number of species found in this study is compared with the numbers reported in the literature for the Mexican Pacific.     

The Afromontane Cladocera (Crustacea: Branchiopoda) of the Rwenzori (Uganda–D. R. Congo): taxonomy,ecology and biogeography

The timely characterization of high-altitude freshwater habitats allows an assessment of the diversity of its biota and provides the basis for monitoring community change. In this study, we investigate the Cladocera fauna of 29 water bodies (pools, freshwater lakes, and surrounding swamps sampled at various occasions between 2005 and 2009) in the Rwenzori Mountains (Uganda, D. R. Congo), which are part of the East African Sky Island Complex. All sites except one are located above 3700 m altitude. We include notes on the morphology, taxonomy, distribution, and ecology of each recorded taxon and describe a new species of the Alona rustica-group (Alona sphagnophila n.sp.; Chydoridae). We found 11 species of which seven are restricted to Lake Mahoma, the lowest lake in our study area (2990 m) (Alona affinis barbata, A. intermedia, Alonella exisa, Alonella nana, Daphnia cf. obtusa, Pleuroxus aduncus) and/or Lake Bujuku (Daphnia cf. curvirostris, P. aduncus) (3900 m). Two taxa (Ilyocryptus cf. gouldeni, A. sphagnophila n.sp.) are restricted to Carex/Sphagnum bogs surrounding lakes in the afroalpine zone. Pigmented populations of Chydorus cf. sphaericus occur in all the sites. It is the only cladoceran species surviving the extreme alpine and nival conditions in the Rwenzori. The species is joined by A. guttata at locations at lower altitudes (ca. 3000–4000 m), present in about half of the sites. The Rwenzori Cladocera fauna is characterized by a strong extratropical temperate component and a low level of speciation/endemism. Harboring an impoverished boreal cladoceran community, Lake Mahoma is given closer attention. At 2990 m, the lake is a cold-temperate aquatic island in the tropics and may function as a stepping stone for Palaearctic taxa. We introduce a new term for high-altitude, cold-water habitats in the tropics, which act as climatic islands for extratropical freshwater faunas, Löffler Islands, in honor of Dr Heinz Löffler. In comparison to surveys in 1961, we list five new records in Lake Mahoma, which could indicate cladoceran community changes over the past few decades at ca. 3000 m in the Rwenzori. Since the species distributions correlate to temperature and catchment properties of the lakes, the Rwenzori cladoceran fauna can be expected as sensitive indicators for local changes.     

Argia mayi, a new species from México (Zygoptera: Coenagrionidae)

A new species of Argia is illustrated and described from material collected in the states of Colima, Guerrero, Jalisco, Michoacán, Morelos and Oaxaca, México. Argia mayi n. sp. is morphologically similar to Argia pocomana Calvert. It differs from the latter by the morphology of the abdominal appendages in the males and by having four postquadrangular cells in FW in both sexes, blue on the dorsum of males restricted to S8-9 and an erect hind margin of the mesostigmal plate in females.     

Paralarval development,abundance, and distribution of Pterygioteuthis hoylei (Cephalopoda: Oegopsida: Pyroteuthidae) in the Gulf of California,México

The morphology and ecology of paralarvae (PL) through to the juvenile stages are unknown in most cephalopod species in spite of their importance as indicators of biodiversity, of adult spawning grounds, and as key basis for fisheries management programs. We describe, for the first time, the morphological development of Pterygioteuthis hoylei (Pfeffer 1912 Pfeffer, G. 1912. Die Cephalopoden der Plankton-Expedition. Zugleich eine monographische übersicht der Oegopsiden Cephalopoden. Ergebnisse der Plankton-Expedition der Humboldt-stiftung, 2: 1–815.  [Google Scholar]) and used cytochrome C oxidase for genetic identification of specimens, linking PL with both juveniles and adults. Pterygioteuthis hoylei represents the most abundant species of squid in oblique plankton collections in the Gulf of California, México. PL were collected in plankton tows made in the Gulf of California from 2004 to 2007. Almost all morphological features followed an increasing size/count trend. Most specimens were collected during March–May, accounting for 71.8% of total cephalopod paralarval abundance, and in November (13.5%). Size, abundance and distribution analyses indicate a high abundance of recently hatched PL (1.1–2.0 mm mantle length) off Bahía Concepción to Bahía de La Paz in these months along with the highest abundance of juveniles and adults in the same area. These results indicate that reproductive activity of P. hoylei takes place in the southern Gulf of California in late winter to early spring, and in November, representing an important spawning and hatching area for this species.     

Presence of Ctenocephalides canis (Curtis) and Ctenocephalides felis (Bouché) infesting dogs in the city of Aguascalientes, México

Prevalence and seasonal distribution of Ctenocephalides canis (Curtis) and Ctenocephalides felis (Bouché) infestations in urban dogs of the city of Aguascalientes, Mexico, were studied. Between January and December 2007, 863 dogs in the Municipal Canine and Feline Control Center were examined. Overall prevalence of infestation was 12% (95% CI 10-14). Seasonal distribution revealed that prevalences in spring and summer were highest, while autumn and winter had lower prevalences. Two infestation peaks were observed, i.e., in April (17.7%) and July (18.9%). A positive correlation was detected between prevalence and temperature during the winter season (P < 0.05). Prevalence in relation to gender showed that males were more frequently infested, 14% (95% CI 11-17), than females, 9.4% (95% CI 7-13); hair length did not affect differences in prevalence. Six hundred twenty-nine fleas were examined; 62% were C. canis and 38% C. felis . Dogs infested with only C. canis were 48% (95% CI 38-58), while 18% were infested only with C. felis (95% CI 11-27); the remainder, 34% (95% CI 24-44), had mixed infestations.     

Nectaropolliniferous Sources Used by Trigona (Tetragonisca) Angustula in Chiapas,Southern México

The nectaropolliniferous flora used by Trigona (Tetragonisca) angustula (Apidae, Meliponinae), was studied by melissopalinological analysis at Chiapas, southern Mexico, in two zones with different altitudes and vegetation (Santa Teresita and Unión Juárez). In both areas monthly samples of honey, pollen, and larval feed were taking for a full year, from a nest established expressly for the purpose. A total of 105 plant species were identified at Santa Teresita, of which only 28 taxa were present in percentages higher than 10; of these, seven taxa are nectariferous, ten nectaropolliniferous and eleven polliniferous sources, of which four taxa are found exclusively in larval food. The values of niche size (H') at Santa Teresita indicated less diversity and availability of sources, in comparison with Unión Juárez, where the evenness values (J') have a tendency toward heterogeneity. At Unión Juárez, a total of 127 plant species were registered of which only 30 taxa were present in frequencies higher than 10%; of these ten species are nectariferous, five taxa are nectaropolliniferous, and 15 species are polliniferous, and of the last category three taxa are found exclusively in brood cells. At Unión Juárez the values of niche size (H') for the three sources are higher than at Santa Teresita, and the evenness (J') values are homogeneous, and showed tendency toward evenness, indicating more diversity and availability in this area.