Ecology and field biology of two dominant Camponotus ants (Hymenoptera: Formicidae) in the Brazilian savannah

Camponotus renggeri and C. rufipes are very abundant in Brazilian cerrado savannah, where they feed extensively on liquid rewards and commonly associate with plants bearing extrafloral nectaries and honeydew-producing insects. Here, we provide a qualitative and quantitative field account on the natural history and ecology of these two ant species. The study was carried out in a cerrado reserve in south-eastern Brazil across a rainy/hot season (summer) and a dry/cold season (winter). The ants were found in two vegetation physiognomies: all nests of C. rufipes were located in the cerrado sensu stricto (scrub of shrubs and trees, 3–8 m tall), whereas C. renggeri occurred mostly in the cerradão (forest with more or less merging canopy, 10–12 m tall). Both species nested in fallen or erect dead trunks, as well as underground. In addition, C. rufipes built nests using dead plant material arranged or not around shrub bases. Colonies of C. rufipes were generally more populous than those of C. renggeri, and both species had colonies with more than one dealated queen. Both species were active mainly at night and foraged for resources near their nests, mainly extrafloral nectar and hemipteran honeydew (aphids and mealybugs). The average size of the home ranges of C. renggeri in cerrado sensu stricto and cerradão varied from ≈ 2.8 to 4.0 m² and apparently were not affected by season. In C. rufipes, however, foraging grounds in cerrado sensu stricto showed a twofold increase from dry/cold (≈ 4.5 m²) to rainy/hot season (≈ 9.8 m²). Our study highlights the importance of natural history data to understand the foraging ecology and role of these ants in cerrado savannah.     

Population dynamics and phenology of two congeneric and sympatric lynx spiders Peucetia rubrolineata Keyserling, 1877 and Peucetia flava Keyserling, 1877 (Oxyopidae)

Numerous phenological studies on spiders belonging to the families Oxyopidae, Thomisidae, Lycosidae, Selenopidae (e.g. Selenops cocheleti) and Salticidae (e.g. Psecas chapoda and Psecas viridipurpureus) have been conducted in the neotropical region. However, studies that simultaneously compare population dynamics and age structure in populations of sympatric species are limited, especially in Oxyopidae. The population dynamics and phenology of two congeneric lynx spider (Peucetia rubrolineata and Peucetia flava) were examined in southeastern Brazil. Several characteristics of the age structure were compared between the two spider species. The variation in the total abundance of individuals and age structure and their relationship with climatic variables were similar between the two spiders. Adults of these spiders were present mainly in spring, indicating an annual reproductive cycle and a ‘stenochronous spring’ phenological pattern. The recruitment of spiders occurred in summer for P. rubrolineata and P. flava, followed by successive phenological peaks at all stages of development. Rainfall and temperature had a positive correlation to population flux in the two spider species studied. Despite the significant climatic effects observed in the Serra do Japi, the phenological pattern of the population in this study was not always repeated in other species of spiders (e.g. Selenops cocheleti).     

Reproductive biology of Scinax fuscomarginatus (Anura,Hylidae) in south‐eastern Brazil

The present study describes the reproductive biology of Scinax fuscomarginatus in a remnant of Cerrado in south‐eastern Brazil. Observations were made between September 2002 and March 2004 at Estação Ecológica de Itirapina, State of São Paulo, south‐eastern Brazil. Breeding activities occurred in lentic and temporary bodies of water during the rainy season. Scinax fuscomarginatus exhibited a prolonged breeding pattern and a lek mating system. Males were smaller than females and defended individual calling areas through acoustic and physical interactions. Resident males consistently won encounters, but did not differ in size or mass from intruder males. Satellite behaviour was observed, but no female or amplected pair interception was registered. Scinax fuscomarginatus exhibited low operational sex ratios and the general reproductive mode in which eggs are laid in the water and tadpoles are aquatic. Amplexus was axillary and the eggs were deposited at the bottom of temporary ponds. Details on oocytes, egg masses, and eggs are included.     

Spatial niche variation in two sympatric species of Bokermannohyla (Anura: Hylidae) in southeastern Brazil

We studied patterns of microhabitat use by adults of two sympatric Bokermannohyla species at the Reserva Particular do Patrimônio Natural Santuário do Caraça, southeastern Brazil. We selected three streams, one where both species occurred in syntopy and the other two where each one occurred alone. We sampled 150-m transects in each stream throughout 1 year, recording microhabitat features for each frog located (substrate type, height and distance from water). Microhabitat availability varied between dry and wet seasons in all streams, and overall microhabitat diversity changed in two streams. Bokermannohyla nanuzae seemed to have a niche contraction in the presence of Bokermannohyla martinsi, but this only happened during the dry season. Microhabitat requirements during the wet season may be closely linked to similar reproductive needs that probably represent a strong selective pressure, forcing niche overlap.     

Activity and reproductive patterns of lizards in the Chaco of Argentina

We studied the activity and breeding pattern of dominant lizard species in the Arid Chaco, the southernmost subregion of the Chaco ecoregion (Chancaní Reserve, Córdoba province, Argentina). Lizards were captured with pitfall traps over a 4-year period. In total, 1449 individuals belonging to 11 of the 12 lizard species recorded in the area were trapped. Of these, we selected six species for a detailed analysis: Teius teyou and Stenocercus doellojuradoi accounted for 63% of the captures, Tropidurus etheridgei, Liolaemus chacoensis and Homonota fasciata accounted for 32%, and 5% comprised Leiosaurus paronae and the remaining five species. All the studied species were active during the warm–rainy season (September to March). Monthly lizard captures were highly correlated with monthly mean temperature and rainfall. No captures occurred during the remaining months of the year. All reproductive tactics known for the Chaco lizards were observed in Chancaní, including single clutch in a short breeding season in summer or autumn, as well as an extended breeding season with multiple clutches. Stenocercus doellojuradoi and L. paronae showed a singular reproductive timing, suggesting the occurrence of egg retention. Compared with sub-tropical Chaco sites, the Arid Chaco only differs in the lack of winter activity, resulting from the lower temperature and rainfall regime of our study site.     

Metazoan parasites of Calophysus macropterus (Siluriformes: Pimelodidae) in the Acre and Iaco rivers in the western Amazon region of Brazil: diversity,similarity and seasonal variation

ABSTRACT

The diversity, similarity and seasonal variation of metazoan parasite communities in Calophysus macropterus in the Acre and Iaco rivers, in the western Amazon (Brazil), was investigated. Parasites from 13 taxa were collected from C. macropterus in both rivers: four species of monogeneans, four nematodes, two cestodes, one digenean, one crustacean and one pentastomid. In hosts from the Acre river, Cucullanus pinnai predominated; while in hosts in the Iaco river, Monticellia amazonica predominated. The component communities of the parasites among the hosts in the two rivers presented high similarity (100%). Prevalence of Alinema amazonicum was higher in hosts in the Acre river; while the prevalence of C. pinnai was higher in hosts in the Iaco river and the mean prevalence and abundance of M. amazonica were higher in fish from the Iaco river. Regarding C. macropterus from the Acre river, infection levels by A. amazonicum were higher during the rainy season, while Demidospermus pinirampi only occurred in the dry season and Procamallanus (Spirocamallanus) inopinatus only occurred in the rainy season. In hosts from the Iaco river, infections by larvae of Anisakidae gen. sp. were higher during the dry season, while infection by Rudolphiella piracatinga and Sebekia sp. only occurred in the rainy season. However, P. (S.) inopinatus, Ergasilus callophysus, Ameloblastella unapi, Demidospermus luckyi, Demidospermus macropteri and D. pinirampi only occurred in the dry season. High similarity of the component communities of the parasite was observed between the rainy and dry seasons. These results suggest that factors other than location and seasonality were influencing the communities and infracommunities of the parasites found. Lastly, C. macropterus is a new host for almost 50% of the parasite species found. In addition, the results from the present study have expanded the geographical range of these 13 species of parasites to the western Amazon region.     

Reproductive ecology of a Tibetan frog Nanorana parkeri (Anura: Ranidae)

Endemic to the Tibetan Plateau, Nanorana parkeri figures among the highest altitude amphibians in the world. The present work, which was conducted in an alpine marsh at 4300 m altitude, is the first report of the species’ reproductive ecology. The breeding season, as indicated by the presence of amplectant pairs and fresh eggs in ponds, lasted from early Mary to early July. The ratios of adult male to female were 1.3 in hibernation ponds and 2.3 in spawning ones. Males were smaller than females. Amplexus was typically axillary (81.7%), with a few exceptional amplexus in which a male clasped another male or object rather than gravid females. Scramble competition occurred in 6.8% of the normal amplexus located. The body sizes of amplexed couples correlated positively. Deposited eggs were attached to submerged plants solitarily (60.5%) or in small clusters (39.5%), and the scattered arrangement of individual eggs could be a strategy to ensure embryonic development in oxygen-poor environments. Clutch size averaged 189 [standard deviation (SD) = 64], and correlated positively with female body size; egg size averaged 2.18 mm (SD = 0.10), independent of female body size; both traits within a clutch were negatively related with each other even controlling for female body size. Relatively few and large eggs laid by the Tibetan frogs, compared with those by lowland aquatic-spawning anuran species, should be adaptive to the harsh high-altitude conditions. Larvae hatched from eggs after 16.4 days on average (SD = 5.8). Froglets emerged between late July and early August, but some tadpoles were present in winter. These findings may help to understand the evolution of amphibians in extreme environments and to protect these remote species.     

Reproductive behaviour of the glass frog Hyalinobatrachium cappellei (Anura: Centrolenidae) in the Southern Amazon

Frog species of the Centrolenidae family exhibit a high variation in reproductive behaviours. Herein we describe the reproductive, ecological, acoustic and behavioural features of Hyalinobatrachium cappellei in Southern Amazon. Two hypotheses were also evaluated: (1) are ecological characteristics of the reproductive site related to male size and quantity of eggs and clutches? And (2) do males with one or more existing clutches at reproductive sites accumulate more new clutches than those males initially without them? This study was conducted at two streams, with sampling at 1 km each in Southern Amazon. Species reproduction occurred during the wet season and was considered prolonged breeding. Although male vocalization occurred on both the upper and underside of leaves, clutches were most often deposited on the underside of leaves. Males emitted a courtship call upon female approach. The process of female approach until oviposition lasted approximately eight hours. After oviposition, females left the breeding site while males remained near the clutch, covering it with the belly in ventral brooding behaviour. Thus, egg attendance is reported for the first time for this species. No intraspecific or interspecific aggressive behaviour was recorded. There was no relationship between habitat characteristics of the reproductive sites and male size, number of eggs and clutches. However, after 10 days of monitoring, we found evidences that parental males had a higher number of clutches than those males initially without clutches. Similar to other glass frog species, the behavioural characteristics of H. cappellei make this species an excellent model to use in evaluating the cost-effectiveness of parental care and the importance of egg attendance for offspring survival. Therefore, these data contribute towards a better understanding of the complex phylogenetic and biogeographic relationships between centrolenid lineages.     

Comparative floral biology of Penstemon eatonii and Penstemon cyananthus in central Utah: a preliminary study

A comparison of the floral visitors of two closely related plant species, Penstemon cyananthus and P. eatonii suggests that flower shape and color may affect the number and type of pollinators, and the ability of the plant to set fruit. Penstemon cyananthus, which is most attractive to hymenopteran visitors, has a blue flower, large in diameter, that is positioned as a convenient “landing pad.” Although many types of insects visit the flower, the transport of pollen directly to flowers of another individual of the same species is somewhat inefficient, since fruiting success is low (66.7 percent). The tubular red flowers of P. eatonii are narrow and droop downward from the stem. The nectar is accessible to a specific and well-adapted visitor, the hummingbird. This less promiscuous, bird-pollinated species sets fruit more successfully (82.4 percent) than P. cyananthus.     

Temporal and seasonal variations in parasites of Metynnis lippincottianus (Characiformes: Characidae), a host from the eastern Amazon (Brazil)

ABSTRACT

This study investigated the influence of temporal and seasonal variation (rainy/dry cycle) on the component community structure and infracommunities of parasites in Metynnis lippincottianus from the eastern Amazon (Brazil). A total of 8,774 parasites representing 9 species and 22,765 parasites representing 12 species was collected in 2011 and 2016 respectively, but only 42.8% of the species were common to both study years. In both years, there was a dominance of Ichthyophthirius multifiliis and the component community was 51% dissimilar. The species richness of parasites and the Berger–Parker dominance were higher in 2016, while the evenness and Brillouin diversity were higher in 2011. The prevalence and abundance of I. multifiliis and P. pillulare, as well as the prevalence of Contracaecum sp. were higher in the rainy season. The abundance of Anacanthorus strongylophalus, Urocleidoides sp., Dadayus pacupeva and Dadaytrema oxycephala was higher in the dry season. Infection with Procamallanus (Spirocamallanus) inopinatus was not influenced by the season, while by Trichodina sp. occurred only in the dry season and Ergasilus xinguensis only in the rainy season. The species richness of parasites, Brillouin diversity index and evenness were higher in the dry season, while the Berger–Parker index was higher in the rainy season. Temporal variation of communities and infracommunities of parasites was influenced by the body size of host populations and increase in anthropogenic impacts. Effect of seasons on environmental quality, host size and availability of infective stages of parasites were the determining factors in structuring the component communities and infracommunities of parasites.     

Reproductive biology of the endangered wattled curassow (Crax globulosa; Galliformes: Cracidae) in the Juruá River Basin,Western Brazilian Amazonia

The reproductive biology of Crax globulosa is virtually unknown, this knowledge comprised of only a few anecdotal notes. We found nine nests of Crax globulosa in the middle section of the Juruá River, western Brazilian Amazon, during the dry season. Nests averaged 22.5 m from water and 13.3 m above the ground. We observed two nest types: five made of twigs, leaves and vines, and four within a bromeliad. All nests contained two eggs, but six (67%) were subsequently predated. A female tagged with a transmitter nested twice during the same breeding season. A chick was monitored together with its parents for > 10 months. In addition to hunting and habitat loss, nest predation could be another threat to this endangered species.     

Polyphagy and florivory prevail in a leaf-beetle community (Coleoptera: Chrysomelidae) inhabiting the canopy of a tropical lowland rainforest in southern Venezuela

ABSTRACT

Embedded within the interdisciplinary research project ‘Towards an understanding of the structure and function of a Neotropical rainforest ecosystem with special reference to its canopy’ organised by the Austrian Academy of Science, the canopy beetle fauna was surveyed by means of a 42 m tall tower crane. This paper presents results of the chrysomelid beetle fauna observed and collected at canopy trees for 1 year. A total of 1783 adult leaf beetles were collected, representing 117 morphospecies (Bruchinae are not included) including 31 singletons. The most abundant family was Galerucinae sensu stricto with 827 individuals (46% of collection). The most speciose subfamilies were Galerucinae sensu stricto followed by Alticini, Cryptocephalinae and Eumolpinae. Nineteen species collected with at least two individuals were restricted to a single tree species whereas 68 species were found to feed on several canopy host trees. Only a few species fed on leaves; these were in Cassidinae, Cryptocephalinae, Eumolpinae and Galerucinae. Strikingly, most canopy chrysomelids were collected at flowers of canopy trees, although some species fed also on extrafloral nectaries or fruits. Alticini were restricted predominantly to flowers, but Cryptocephalinae, Eumolpinae and Galerucinae revealed broader plasticity in host tissue selection. Insights into beetle seasonality, diurnal/nocturnal activity and intra-canopy migration are provided. Abundant flower-visiting species occurred on their host trees commonly over the entire flowering season, with their abundances often correlated with the number of open flowers. After termination of one tree’s flowering season, many flower-visiting leaf beetles moved to other flowering trees. Certain congeneric species of Galerucinae and Eumolpinae occurred together at their host plants within the same periods.     

Life cycle and population structure of the terrestrial isopod Hemilepistus klugii (Brandt, 1833) (Isopoda: Oniscidea) in Iran

The life cycle and population structure of Hemilepistus klugii were studied in a population in Varamin, Iran. The population was sampled monthly (or fortnightly during the breeding season) from February 2008 to June 2009 and a total of 7015 individuals, comprising 1069 males, 1079 females and 4867 juveniles, were collected. As in other Hemilepistus species, five distinct phenophases, namely pair formation, gestation, hatching, growth and stationary, were recorded during the life cycle of H. klugii. The overall sex ratio was 1 : 1 but varied over time. Ovigerous females were observed only in April, indicating a seasonal and very short breeding period. With a short lifespan after breeding, females demonstrated true semelparity. The mean cephalothorax width for ovigerous/post-ovigerous females was higher in 2008 than in 2009. These females attained the largest size in the population throughout the year. The number of eggs per female ranged from 28 to 147 (mean ± SE, 78 ± 1.8). There was a positive correlation between female size and fecundity. Recruitment occurred in late April and resulted in the highest population density in this month, whereas the lowest densities were observed during November to January. Despite a high percentage of ovigerous females carrying undeveloped eggs (72.3%), intramarsupial mortality was low (3.5%).     

Nesting biology and behavioural ecology of the solitary bee Monoeca haemorrhoidalis (Smith) and its cleptoparasite Protosiris gigas Melo (Hymenoptera: Apidae: Tapinotaspidini; Osirini)

The species Monoeca haemorrhoidalis, the largest species in the genus, occurs in the Atlantic rainforest of southeastern and southern Brazil. The aim of this study was to investigate the nesting ecology of M. haemorrhoidalis and its interactions with natural enemies. Nest aggregations were studied in an area at the transition between Dense and Mixed Temperate Rainforest, south Brazil. The period of nest construction and cell provisioning started in October and stopped in February. Plant species of the families Orchidaceae, Styracaceae and, mainly, Malpighiaceae, were the most important pollen and floral oil resources that were used in brood cell provisioning. During the nest construction activities, 27 insect species were observed at the nesting sites. The cleptoparasitic bee Protosiris gigas was one of the main causes of M. haemorrhoidalis mortality. Some behavioural and biological data of P. gigas are also reported.     

Notes on the occurrence and biology of Xenoclarias Greenwood (Siluriformes: Clariidae) in Lake Victoria,East Africa

Summary

Xenoclarias inhabits the deeper (>50 m) waters of Lake Victoria. Specimens captured in a bottom trawl ranged in size from 10–22 cm TL (mode, 15–18 cm) and females grew to a larger size than males. Length-weight relationships between sexes were different only in the Kenya waters and resulted in significantly different KTL. Based on gonadal stages, Xenoclarias matured between 14–16 cm (age 1). Fecundity of 6 specimens (Stage VI) ranged from 744–1357 (mean 1009) and egg size from 1·45 to 1·98 mm (mean 1·79 mm).

Based on gravid and spawning females, Xenoclarias spawned prior to the rainy season (January–March) in Kenya and Uganda waters. During periods of increased reproductive activity females were consistently more numerous in samples (2:1) than males. Local meteorological and hydrological conditions may explain the apparently different spawning season in Tanzania waters of the Lake. This genus of small fish is not affected by the artisinal gillnet fishery but may be by the expansion of a bottom trawl fishery in Lake Victoria.     

Reproductive ecology of the glass frog Espadarana prosoblepon (Anura: Centrolenidae) in an urban forest of the Central Andes of Colombia

Population and reproductive behaviour aspects of the glass frog Espadarana prosoblepon are well known for populations from Central America, but similar information is lacking for populations from South America. We recorded the reproductive ecology of a population of the glass frog E. prosoblepon in the city of Armenia, Central Andes of Colombia. With weekly surveys with mark-recapture between December 2013 and November 2015, we monitored activity patterns and evaluated if the probability of males mating is associated to their body size or to chorus tenure (i.e. the number of nights a same individual is calling for attracting a mate). In addition, upon observing an amplexus, we recorded the behaviour of the individuals until oviposition and noted characteristics of egg clutch. We recorded 47 males and 32 females, nine amplexus events, eight ovipositions, and 21 egg clutches (35.4 ± 4.79 eggs per clutch, N = 29). Activity of males and females and the number of egg clutches were positively correlated to rainfall. Mating success of males was not associated to their body size, but it was positively associated to longer chorus tenure; clutches from large females had a higher number of eggs than clutches from small females. Oviposition occurred on average 3.76 ± 1.74 hours after we first observed the amplexus, occurring 93.1% of the time in fronds of Selaginella geniculata at an average height of 1.58 ± 0.44 m. After the oviposition, the male left the site, while the female remained between 30 and 45 min, partially covering the eggs. The reproductive behaviour of E. prosoblepon did not vary widely between a population in Costa Rica and our population in time to oviposition, and mating success of males associated to chorus tenure; however, in our study population we recorded a larger clutch size and the preference for S. geniculata fronds as oviposition substrate.     

Habitat use by the South‐American rattlesnake (Crotalus durissus) in south‐eastern Brazil

Habitat use affects food intake, reproductive fitness and body temperature control in reptiles. Habitat use depends on both the characteristics of the animal and the environmental heterogeneity. In this study we investigated habitat use in a population of the South‐American rattlesnake, Crotalus durissus, in a cerrado (the Brazilian savanna) remnant, in south‐eastern Brazil. In general, snakes appeared to be thermal generalists. However, they showed substrate temperature preferences in the rainy season, when they selected colder substrates during the day and warmer substrates at night. Individuals were predominantly active on the surface and more frequently found under bushes. Furthermore, in general, the principal component analysis results indicate that rattlesnakes are generalists regarding the microhabitat variables examined in this study. These habitat characteristics, associated with a low thermal selectivity, indicate that rattlesnakes are able to colonize deforested areas where shade occurrence and vegetation cover are similar to those in the cerrado.     

Strong phenological differences between two populations of a Neotropical funnel-web wolf spider

Comparisons of phenological patterns among populations within a species are uncommon in arachnids. Aglaoctenus lagotis is a wolf spider that lives in funnel-webs across South America. The aim of this study was to describe the phenological patterns of two distant populations of A. lagotis (central Argentina, CA, and southern Uruguay, SU). Individuals of each population were sighted along transects, every month for two years. The CA and SU populations differed in their phenological patterns (Wald χ² = 966.94, df = 66; p <0.001). The CA population showed a spring–summer unified reproductive season and immature individuals overwintered. SU showed the sexual period during autumn, the maternal period during spring–summer and the females, mostly mated, overwintered. These strong differences imply temporal isolation in mating possibilities between both populations. The differences encountered could be due to phenotypic plasticity or have a phylogenetic basis. Interpopulation studies of other features of A. lagotis would show whether they also vary, suggesting speciation.     

Activity and reproduction in Megalobulimus paranaguensis (Gastropoda,Eupulmonata): implications for conservation in captivity for a South American land snail

ABSTRACT

In South America, Megalobulimus includes a number of threatened species, as well the largest land snails on the continent. The activity patterns and reproductive aspects of this group have not been documented. This work describes the daily and seasonal activity patterns and reproduction of M. paranaguensis. We maintained specimens in the laboratory for one year, and we quantified their behaviour for one hour at four different times of the day (0 h, 6 h, 12 h and 18 h) during three days in four months (August, September, April and May). The number of postures, hatching rate, time of hatching since oviposition and mortality rate among juveniles for each month were also quantified. Megalobulimus paranaguensis was more active in August, and had a egg laying peak one month after. Fifty-one eggs were laid by 12 captive individuals throughout the year, with a mean value of 4.25 eggs per individual. The hatching rate was 80.39%, and the time of hatching since oviposition was 56.7 ± 4.3 days. In two eggs, we observed the presence of twins. The mortality rate among juveniles was low (9.30%) indicating that rearing land snails in captivity has the potential to be an important and viable tool for the management and conservation of these organisms.