Preliminary survey ofCacajao melanocephalus melanocephalus in Southern Venezuela

We conducted a survey of Cacajao melanocephalus melanocephalusin southern Amazonas, Venezuela, to update information on their distribution and to select a site for a longitudinal study. We surveyed along the Rio Negro, Brazo Casiquiare, Rio Pasimoni, and Rio Baria and interviewed local people. We observed C. m. melanocephalusfour times along the Rio Pasimoni (N =2)and the Rio Baria (N =2).Group size ranged from 3 to 20 individuals. They ate immature seeds from heavily armored fruit of the chicletree (Manilkara bidentataor Manilkara zapota)and Mauritia flexuosa.Local people reported hunting primates, particularly C. m. melanocephalus,once per week. Mercury residue from illegal gold mining may be poisoning local ecosystems. Hunting pressures may have eliminated C. m. melanocephalusfrom much of its range in southern Amazonas. Urgent steps must be taken toward the conservation of C. m. melanocephalus irathis region.     

Southern expansion of the geographical distribution ofCacajao melanocephalus melanocephalus

Cacajao melanocephalus melanocephalus, a subspecies of black uakari, was thought to be restricted to southern Venezuela. Observations of two groups of them in Pico da Neblina National Park, Brazil, suggest that its distribution should be extended to the Brazilian territory.     

Spatial patterns of host exploitation in a larval parasitoid of the predatory dusky large blue Maculinea nausithous

The foraging behaviour of the parasitoid wasp Neotypus melanocephalus and factors affecting parasitism at the population level were studied. This specialised parasitoid attacks caterpillars of the butterfly Maculinea nausithous, which sequentially feed on the plant Sanguisorba officinalis and specific red Myrmica ants. Among M. nausithous populations, there is considerable variation in caterpillar densities. At low M. nausithous densities, foraging might be time consuming for N. melanocephalus. High host densities may not always be advantageous to foraging parasitoids due to the caterpillars’ frequent overexploitation of ant resources and subsequent density-dependent mortality. In order to disperse progeny, we hypothesised that N. melanocephalus should search in a non-random way at the level of the micro-habitat, i.e., single flower heads of S. officinalis. Our analysis of 32 natural populations in the Upper Rhine valley in Germany did not show a density-dependent relationship between M. nausithous caterpillars and parasitism. Furthermore, habitat parameters like patch size and density of the host's food plant did not affect the parasitism rate. Foraging N. melanocephalus females preferred to search on large flower heads. They probed host-occupied flower heads only, visiting non-host-exploited flower heads only briefly. Time spent on a flower head was independent of the number of caterpillars per flower head. This study indicates that N. melanocephalus increases its foraging efficiency by preferring large flower heads that were previously shown to contain more host caterpillars than small flower heads. Furthermore, oviposition increases the likelihood of continuing to search on a flower head, which is an adaptive strategy for parasitoids foraging for aggregated hosts. However, many host-occupied flower heads were not probed by N. melanocephalus. We discuss the possibility that temporal host refuges of M. nausithous caterpillars might contribute to heterogeneity of parasitism, and why spreading offspring might constitute a suitable strategy for a parasitoid of an ant-parasitic butterfly.     

Observations onChiropotes albinasus from the Rio dos Marmelos,Amazonas, Brazil

Notes are presented on the body size, behaviour, diet, and gut morphology ofChiropotes albinasus from the Rio dos Marmelos in southeastern Amazonas state, Brazil. Findings include a new upper limit of body weight for the species, gut proportions consistent with its relatively high quality diet and evidence of geophagy.     

Modeling the Geographical Distribution and Fundamental Niches of <Emphasis Type="Italic">Cacajao</Emphasis> spp. and <Emphasis Type="Italic">Chiropotes israelita</Emphasis> in Northwestern Amazonia via a Maximum Entropy Algorithm

We modeled the geographical distribution of 4 pithecine primate species: brown-backed bearded sakis (Chiropotes israelita) and 3 black uakaris (Cacajao melanocephalus, C. hosomi, and C. ayresi) that inhabit remote regions of western Amazonas, Brazil. We applied a maximum entropy algorithm modeling program (MAXENT) to field data Boubli collected from 1991 to 2007. We used 23 environmental coverage variables to model the distribution of the primates. The layers were related to precipitation, temperature, topography, and ecological bioregions or Ecoregions. The predicted distribution for Cacajao hosomi was strongly associated with the Negro-Branco Moist Forest and Guianan Highlands Moist Forests Ecoregions, and the Worldclim variables Bio3 (isothermality), Bio4 (temperature seasonality) and Bio17 (precipitation of the driest quarter). Cacajao melanocephalus was strongly associated with Japurá/ Solimões-Negro Moist Forests, Caquetá Moist Forests, Purús Várzea Flooded Forests, Rio Negro Campinaranas, and Cordillera Oriental Montane Forests, Ecoregions. Cacajao ayresi was strongly associated with Negro-Branco Moist Forest and Rio Negro Campinarana Ecoregions as well as Worldclim Bio3 (isothermality). Chiropotes israelita was also strongly associated with Worldclim Bio3 (isothermality) followed by the Negro Branco Moist Forests and Guianan Piedmont and Lowland Moist Forests Ecoregion, and to the Guianan Highland moist forests. These results show a great overlap between the bearded saki and 2 black uakaris, Cacajao hosomi and C. ayresi. Given that one cannot attribute the separation between the species in the Rio Negro-Rio Branco interfluvium to the existence of geographical barriers such as rivers, we suggest that the present geographical boundaries and thus coexistence of the 3 pithecines north of the Rio Negro is maintained by competitive exclusion or stochastic events. Until more surveys are conducted, the present geographical distributions of the pithecines and the mechanism maintaining their boundaries in the Rio Negro-Rio Branco interfluvium will remain uncertain. One important contribution of our model is to identify areas of higher probability of occurrence that might be helpful in guiding future survey expeditions and choices of areas for future conservation of pithecines.     

Moenkhausia celibela: a new species from the Amazon basin,Brazil (Characiformes: Characidae)

A new species of Characidae, Moenkhausia celibela, is described from the Rio Amazonas at Santarém, Rio Maraú, several localities in the Rio Tapajós, Rio Curuá‐Una, Rio Xingu and Rio Jari, all from the Amazon basin, Brazil. The new species is distinguished from its congeners, except species included in Géry's 1992 Moenkhausia lepidura group, by presenting a dark blotch on the upper caudal‐fin lobe, and the lower lobe is hyaline or light grey. Moenkhausia celibela is distinguished from the species of the M. lepidura group by the absence of a humeral spot and the presence of a roughly triangular and dark spot at the caudal‐fin base, extending posteriorly along the middle caudal‐fin rays, and distinctly separate from the spot on the upper caudal‐fin lobe.     

Rhynchospora pseudomacrostachya, a new Brazilian species of Cyperaceae

Rhynchospora pseudomacrostachya (Cyperaceae) is restricted to the southern Brazil states of Rio Grande do Sul and Santa Catarina. Previously, material ofR. pseudomacrostachya had been thought to belong toR. corniculata var.macrostachya (Torr. ex A. Gray) Britton (R. macrostachya Torr. ex A. Gray) of North America. However,R. pseudomacrostachya can be distinguished from the North American taxon on the basis of achene and inflorescence characters.     

On the relationship between reproduction,age and survival in two carbid beetles:

Summary In this study the inverse relationship between the amount of reproduction in female carabid beetles and their survival until the next breeding season, suggested by Murdoch (1966), was examined in Pterostichus coerulescens L. and Calathus melanocephalus L. This was tested with individual and differently reproducing females, kept at the same temperature, as well as with groups of females kept at different temperatures, i.e. with very different overall levels of reproduction.No relationship was found between the numbers of eggs laid by individual females and their survival until the next breeding season.The numbers of eggs laid by individual females varies greatly, even under constant and optimal conditions,. In contrast to this, an individual female continues to lay a characteristic number of eggs over several succeeding weeks. The amount of reproduction is highly correlated with temperature when food is optimal. In P. coerulescens there was a positive correlation between the amount of reproduction of the same individuals in two succeeding years, whereas in C. melanocephalus no relationship could be found.Both in the field and in our experiments individuals of P. coerulescens generally live for 3 to 4 years, longer than C. melanocephalus which usually only lives for 2 years. The 3–4 year-old individuals of P. coerulescens die during the breeding season or shortly afterwards, but also during the winter, whereas the 2–3 year-old individuals of C. melanocephalus die during the winter. Males and females show a similar mortality after breeding. The level of reproduction of a population depends on the proportion of old beetles, since especially the very old ones die before the end of the breeding season.We reject the hypothesis of Murdoch because of these data. However, in a different way from that of Murdoch, we also suggest that old beetles are of great importance for the survival of a population, namely that this form of heterogeneity of a population may enhance its stability under varying environmental conditions.Communication No. 204 of the Biological Station, Wijster     

Colony-structure variation and interspecific competitive ability in the invasive Argentine ant

The success of some invasive species may depend on phenotypic changes that occur following introduction. In Argentine ants ( Linepithema humile) introduced populations typically lack intraspecific aggression, but native populations display such behavior commonly. We employ three approaches to examine how this behavioral shift might influence interspecific competitive ability. In a laboratory experiment, we reared colonies of Forelius mccooki with pairs of Argentine ant colonies that either did or did not exhibit intraspecific aggression. F. mccooki reared with intraspecifically non-aggressive pairs of Argentine ants produced fewer eggs, foraged less actively, and supported fewer living workers than those reared with intraspecifically aggressive pairs. At natural contact zones between competing colonies of L. humile and F. mccooki, the introduction of experimental Argentine ant colonies that fought with conspecific field colonies caused L. humile to abandon baits in the presence of F. mccooki, whereas the introduction of colonies that did not fight with field colonies of Argentine ants resulted in L. humile retaining possession of baits. Additional evidence for the potential importance of colony- structure variation comes from the Argentine ants native range. At a site along the Rio de la Plata in Argentina, we found an inverse relationship between ant richness and density of L. humile (apparently a function of local differences in colony structure) in two different years of sampling.     

Uacaries,new world monkeys of the genus Cacajao(Cebidae,Platyrrhini): A preliminary taxonomic review with the description of a new subspecies

The two known species of uacaries, inhabitants of the upper Amazonian region, are the black head Cacajao melanocephalus with subspecies C. m. melanocephalus Humboldt and C. m. ouakary Spix, and the larger bald head uacari C. calvus with subspecies C. c. ucayalii Thomas, C. c. rubicundus I. Geoffroy and Deville, C. c. calvus I. Geoffroy, and C. c. novaesi described as new. The diagnostic generic characters described are the external, cranial, dental, some postcranial, and cytogenetic. The species are described and compared and their geographic distribution plotted with those of their subspecies delimited. Sexual differences are outlined. Apart from size-related characters, the species and subspecies are distinguished by pelage pattern of head and coloration in general. It is shown that both species could have diverged from a hairy-headed melanistic ancestral form. Pelage divergence in the descendants was expressed by the more pilose head of C. melanocephalus, and less pilose of C. calvus. Coloration differentiation was geographic and followed metachromic lines with mutation from eumelanism to partial pheomelanism (reddish or golden) in C. melanocephalus and to virtually complete pheomelanism in C. calvus. The subspecies of each species are distinguished by color patterns resulting from selective bleaching or dilution of the pheomelanin fields. The most saturate pheomelanic subspecies of C. calvus is C. c. ucayalii and the most dilute is the albinotic C. c. calvus. Correlation between coloration and environment is not evident. A gazetteer identifies all locality records plotted by numbers on the geographic distribution maps.     

Contribution of genetic distances studies to the taxonomy ofAteles,particularlyAteles paniscus paniscus andAteles paniscus chamek

We studied 20 electrophoretic loci in two populations ofAteles (Ateles paniscus paniscus andAteles paniscus chamek). We observed intrapopulational variation at the following loci: esterase D, glyoxalase 1, adenosine deaminase (A. p. chamek) and carbonic anhydrase 2 (A. p. paniscus). The two populations share the most frequent alleles at 17 loci, but we noted great differences in glyoxalase 1, adenosine deaminase and phosphoglucomutase 1.A. p. paniscus is monomorphic for theGLO1 ^*1 allele, which has a frequency of 6% inA. p.chamek. They did not share alleles in relation to the ADA and PGM1 loci. We found a CA2 allele, named hereCA2 ^*1, which has not been described previously in other neotropical primates (Sampaio et al., 1991a), inA. p. paniscus. The present results suggest that the geographical isolation represented by the Rio Amazonas has lasted long enough to support this level of divergence. These observations taken together with chromosomal findings, led us to endorse the proposal of two distinct species:Ateles paniscus andAteles chamek.     

The Electric Glass Knifefishes of the Eigenmannia trilineata species‐group (Gymnotiformes: Sternopygidae): monophyly and description of seven new species

Eigenmannia trilineata López and Castello, 1966 (Sternopygidae) was described from the Río de La Plata basin and subsequently cited from most South American river basins. Questions about the limits of this species raise the possibility of the occurrence of undescribed species misidentified as E. trilineata. Herein we propose the Eigenmannia trilineata species group for species that share the presence of the superior medial stripe on the flank. This group comprises: E igenmannia antonioi sp. nov. , from the Rio Anapu, Rio Amazonas basin; E igenmannia desantanai sp. nov. , from the Rio Cuiabá, Rio Paraguay basin; E igenmannia guairaca sp. nov. , from the Riacho Água do Ó, upper Rio Paraná basin; E igenmannia matintapereira sp. nov. , from the Rio Uneiuxi and Rio Urubaxi, Rio Negro basin; Eigenmannia microstoma (Reinhardt, 1852), from the Rio São Francisco basin; E igenmannia muirapinima sp. nov. , from small tributaries of the Rio Amazonas; E igenmannia pavulagem sp. nov. , from the tributaries of Rio Capim, Rio Guamá basin; E. trilineata, from the lower Rio Paraná basin and Río de La Plata basin; Eigenmannia vicentespelaea Triques, 1996, from São Vicente I and II caves, Rio Tocantins basin; and E igenmannia waiwai sp. nov. , from the Rio Trombetas basin. These species can be distinguished from each other by unique sets of meristics, morphometrics, osteological and colour pattern features. © 2015 The Linnean Society of London     

Four new species of the Didymopanax group of <Emphasis Type="Italic">Schefflera</Emphasis> (Araliaceae) from the Brazilian Amazon

Four new species of the Didymopanax group of Neotropical Schefflera (Araliaceae) from the Brazilian Amazon are here described and illustrated. Two of these are mainly known from the surroundings of Manaus, Amazonas state (Schefflera ciliatifolia and Schefflera umbrosa). The first is distinguished by its ciliate leaflets, while the second is characterized by leaflets varying in shape from trilobed to entire. Schefflera plurifolia is known only from southern Amazonian forests, and is remarkable in its pinnately-compound leaflets. Schefflera dichotoma, only known from the type collected on “campinarana” forests from Upper Rio Negro, at the municipality of São Gabriel da Cachoeira (Amazonas), is characterized by dichotomously branching inflorescences. Comments on the geographic distribution and ecology of the new species are provided, as well as an identification key to the species of the Didymopanax group found in Brazilian Amazonian rainforests and savannas.     

Microsatellite analyses of the trout of northwest Mexico)

The trout of northwest Mexico represent an undescribed group of fish considered part of the Oncorhynchus mykiss (Pacific trout) complex of species and subspecies. Recent genetic studies have shown these fish to have important genetic diversity and a unique evolutionary history when compared to coastal rainbow trout. Increased levels of allelic diversity have been found in this species at the southern extent of its range. In this study we describe the trout in the Sierra Madre Occidental from the rios Yaqui, Mayo, Casas Grandes and de Bavispe, and their relationship to the more southern distribution of Mexican golden trout (O. chrysogaster) using 11 microsatellite loci. Microsatellite allelic diversity in Mexican trout was high with a mean of 6.6 alleles/locus, average heterozygosity=0.35, and a mean F _st=0.43 for all loci combined. Microsatellite data were congruent with previously published mtDNA results showing unique panmictic population structure in the Rio Yaqui trout that differs from Pacific coastal trout and Mexican golden trout. These data also add support for the theory of headwaters transfer of trout across the Continental Divide from tributaries of the Rio de Bavispe into the Rio Casas Grandes. Rio Mayo trout share a close genetic relationship to trout in Rio Yaqui, but sample sizes from the Rio Mayo prevent significant comparisons in this study. Microsatellite analyses show significant allelic frequency differences between Rio Yaqui trout and O. chrysogaster in Sinaloa and Durango Mexico, adding further support for a unique evolutionary status for this group of northwestern Mexican trout.     

Observations on the life cycle and establishment ofCochylis atricapitana (Lep: Cochylidae), a moth used for biological control ofSenecio jacobaea in Australia

Larvae of the mothCochylis atricapitana (Stephens) are monophagous leaf, crown, stem or bud borers of ragwort,Senecio jacobaea L. (Asteraceae). In the present investigation, aspects of the life cycle ofC. atricapitana were determined. Moths ofC. atricapitana lay an average of 158 eggs/female with as many as 355 eggs being laid by a single female. The majority of eggs are laid individually along the primary and secondary veins on the underside of ragwort leaves. Egg incubation ranges from 4.2 days at 30°C to 14.4 days at 15°C. At a constant 23°C under a 16 hour photoperiod,C. atricapitana takes approximately 40 days to complete a generation. Caterpillars make their way to young, actively growing ragwort shoots or buds, and begin mining into the plant tissue, boring into the leaf, crown, stem or bud.C. atricapitana has five larval instars and enters diapause as a final instar larva. In southern Victoria, moths ofC. atricapitana fly from late September through to the beginning of February. Adults emerge after overwintering towards the end of spring or beginning of summer.C. atricapitana has established at two sites while larvae, or signs of damage have been observed at approximately 52% of release sites.      

Parasitoids acquired byColeophora parthenica [Lepidoptera: Coleophoridae] ten years after its introduction into southern California for the biological control of Russian thistle

Parasitism of the stem and branch-boring mothColeophora parthenica Meyrick [Lepidoptera: Coleophoridae], introduced into California for the biological control of Russian thistle,Salsola australis R. Brown [Chenopodiaceae] was studied in the Coachella Valley of southern California during 1985–1986. Eight parasitoid species were reared from overwintering larvae ofC. parthenica, but none from the F₁ larvae, and just 2 individuals of one species from the F₂ summer generation. The level of parasitism of overwintering larvae was positively correlated with branch diameter, and ranged from 2% in the primary (main) branches to 45% in the tertiary branches in the spring 1985 sample, and from 2% to 19% in the spring 1986 sample, respectively. Rates of parasitism>20% were only found at sites with higher plant cover and chenopod diversity, but no other plant source or alternate hosts of the parasitoids ofC. parthenica were found. The 2 dominant species, the solitary, hymenopterous ectoparasitoids,Norbanus perplexus (Ashmead) [Pteromalidae] andEurytoma strigosa Bugbee [Eurytomidae], are both congeners of native parasitoids ofC. parthenica in Pakistan. The 2 other species of parasitoids ofC. parthenica in southern California for which other hosts are known are polyphagous and external on the larvae. No specialized endoparasitoid Braconidae, like those which dominate the native parasitoid complex in Pakistan and the U.S.S.R., have transferred toC. parthenica during its first 10 years in southern California.      

Infection of Sentinel Cotton Aphids (Homoptera: Aphididae) by Aerial Conidia ofNeozygites fresenii(Entomophthorales: Neozygitaceae)

Uninfected adultAphis gossypii(Homoptera: Aphididae) apterae (sentinel aphids) on cotton leaves were exposed for 8 h to the air over a commercial cotton field in Louisiana during the night of 1–2 July 1995. At 0015 h there were 90,437 primary conidia/m³air of the fungusNeozygites fresenii(Entomophthorales: Neozygitaceae) at the midfield position as determined from Rotorod samples. Forty-eight percent (n = 106) of the sentinel aphids exposed for 8 h at midfield were infected by aerial conidia ofN. fresenii.Exposure of sentinel aphids outside the cotton field, at 10 and 100 m downwind and 10 m upwind, resulted in 34.8% (n = 131), 24.0% (n = 129), and 17.4% (n = 146) infected aphids, respectively. These data demonstrate that wind-dispersed aerial conidia ofN. freseniiare infective and rapidly and efficiently disperse the pathogen throughout aphid populations within and between fields.     

Suppression of Boll Weevil Infestations (Coleoptera: Curculionidae) Occurring on Fallow-Season Cotton in Southern Texas by Augmentative Releases ofCatolaccus grandis(Hymenoptera: Pteromalidae)

Augmentative releases ofCatolaccus grandis(Burks) were conducted in the Lower Rio Grande Valley of Texas in an attempt to suppress infestations of boll weevil,Anthonomus grandisBoheman, occurring in stands of “fallow-season” cotton (i.e., fields in violation of the 1 September stalk destruction deadline mandated by Texas law). In each of five release sites monitored during the study period (October, 1994–March 1995), augmentative releases ofC. grandiswere accompanied by an appreciable increase in the incidence of parasitized boll weevils (primarily third-stage larvae and pupae infesting abcised cotton squares) within a relatively brief time period. The relatively high incidence of host mortality caused byC. grandisin each release site was largely indispensible (i.e., would not have occurred in the absence of the parasite) and served to destroy significant numbers of immature boll weevils that appear to have been predisposed to successfully overwinter. The potential role of parasite augmentation in the management of the overwintering boll weevil population in southern Texas is discussed.     

Discrimination of red porgy Pagrus pagrus (Sparidae) potential stocks in the south-western Atlantic by otolith shape analysis

Otolith shape analysis is a powerful method for fish stock identification. We compared the otolith shape of Pagrus pagrus (Linnaeus 1758) along with its distribution in four south-western Atlantic regions where it is commercially fished: Rio de Janeiro, Rio Grande do Sul in southern Brazil, the Argentine-Uruguayan Common Fishing Zone (UA) and the Argentinian Exclusive Fishing Zone (AR). Otolith shapes were compared by Elliptical Fourier and Wavelet coefficients among specimens in a size range with similar otoliths, morphometric parameters and ages. Four potential stocks were identified: one in the AR, a second along the UA which included specimens from southern Brazil with well-marked opaque bands in its otoliths (MRS), the third in southern Brazil with faint or absent opaque bands in its otoliths (FRS) and the fourth along Rio de Janeiro. The difference in the otolith shape among regions followed differences reported using other stock identification techniques. The similarity between otoliths from UA and MRS (ANOVA-like, P > 0.01) can be explained by seasonal short-range migrations. Otoliths shape differences between MRS and FRS (ANOVA-like, P < 0.01) suggest that P. pagrus does not form a homogeneous group in southern Brazil.