Microsatellite markers for the palaeotropic pioneer tree genus Macaranga (Euphorbiaceae) and their cross‐species transferability

We developed primer sequences for five polymorphic microsatellite loci in the tropical ant‐plant genus Macaranga (Euphorbiaceae). Population genetic parameters were determined on the basis of 30 individuals from each of two Macaranga species in Borneo. Allele numbers per locus ranged from three to 13. Expected and observed heterozygosities ranged from 0.160 to 0.850 and from 0.130 to 0.700, respectively. Four of the five primer pairs cross‐amplify polymorphic PCR products in a wide range of Macaranga species.     

The evolution of waving displays in fiddler crabs (Uca spp., Crustacea: Ocypodidae)

Male fiddler crabs are commonly recognized by the presence of a single massive claw used in a variety of contexts, including territorial defence, agonistic interactions, and courtship behaviour. The most common behavioural context involving these enlarged chelipeds is their use in waving displays, which are remarkably diverse among species. Although the waving display is one of the most obvious behavioural features of male fiddler crabs, little is known about their main evolutionary trends during the diversification of the genus. The present study employed phylogenetic comparative methods to investigate the evolution of waving behaviour in a sample of 19 species of Uca from Central and North America. Digital recordings were used to quantify the temporal dynamics of waving behaviour in each species. Multivariate ordination methods were used to assess whether different elements of the display showed distinct evolutionary dynamics, particularly with respect to body size and the environment where species are most commonly found. Most of the interspecific variation in displays involves differences in the overall waving velocity, with no correspondence to their local environments, nor their body size. Interestingly, despite the strong concentration of variance in the first two ordination axes, there was no statistically significant evidence for phylogenetic signals in their respective scores. These results suggest that the overall structure of waving displays is evolutionarily labile, at the same time as being concentrated in a few particular axes of variation, possibly indicating evolution along lines of least resistance. The approach employed in the present study highlights the utility of phylogenetic comparative methods for elucidating the evolution of complex behavioural characteristics, such as the waving display in male fiddler crabs. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 307–315.     

Molecular phylogeny and diversification history of Prosopis (Fabaceae: Mimosoideae)

The genus Prosopis is an important member of arid and semiarid environments around the world. To study Prosopis diversification and evolution, a combined approach including molecular phylogeny, molecular dating, and character optimization analysis was applied. Phylogenetic relationships were inferred from five different molecular markers ( mat K- trn K, trn L- trn F, trn S- psb C, G3pdh, NIA). Taxon sampling involved a total of 30 Prosopis species that represented all Sections and Series and the complete geographical range of the genus. The results suggest that Prosopis is not a natural group. Molecular dating analysis indicates that the divergence between Section Strombocarpa and Section Algarobia plus Section Monilicarpa occurred in the Oligocene, contrasting with a much recent diversification (Late Miocene) within each of these groups. The diversification of the group formed by species of Series Chilenses, Pallidae, and Ruscifoliae is inferred to have started in the Pliocene, showing a high diversification rate. The moment of diversification within the major lineages of American species of Prosopis is coincident with the spreading of arid areas in the Americas, suggesting a climatic control for diversification of the group. Optimization of habitat parameters suggests an ancient occupation of arid environments by Prosopis species.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 621–640.     

Effect of thermal acclimation on preferred temperatures in two mygalomorph spiders inhabiting contrasting habitats

Variations in the preferred temperatures during the rest periods of Grammostola rosea Walckenaer and Paraphysa parvula Pocock, two mygalomorph spiders occupying different habitats in central Chile, are analyzed. The former inhabits arid and semi‐arid lowland near plant communities, composed of shrubs (evergreens with small leathery leaves) and small trees; the latter is found in the central mountains of the Chilean Andes, above 2000 m.a.s.l. The preferred temperatures of these spiders at different times of day and exposure to cold (15 °C) and warm (25 °C) acclimation temperatures are compared. Body mass does not affect the preferred temperature of the larger spider G. rosea, although P. parvula, a spider with half of the body mass of G. rosea, shows a decrease in preferred temperature with body mass. This can be explained by a higher plasticity and thermal sensitivity of the smaller species as result of increased surface : volume ratio. The preferred temperature increases with the hour of the day under both acclimation conditions in P. parvula and in cold‐acclimated G. rosea, which is likely associated with crepuscular and nocturnal behaviour in both species. Grammostola rosea shows temperature preferences lower than those of P. parvula under both acclimation conditions. The increase of the acclimation temperature from 15 to 25 °C results in an increment of 2–3 °C in the preferred temperature of P. parvula but only 0.2 °C in that of G. rosea. Two contrasting lifestyle strategies are found: a small mygalomorph spider with phenotypic plasticity and adaptation to the fluctuating environment of high altitude, and a large mygalomorph spider with higher thermal inertia adapted to the more stable environment of lowlands.     

Do reproductive activities compromise immunological competence as measured by phenoloxidase activity? Field and experimental manipulation in females of two damselfly species

Recent studies of female insects indicate that reproductive activities, such as mating and oviposition, can impair immune ability. Using the two tropical damselfly species Argia anceps Garrison and Hetaerina americana (Fabricius), egg production and phenoloxidase (PO) activity, a key enzyme in insect immunity, are measured in mating, ovipositing and perching females in December and March. Perching females of both species have fewer eggs compared with mating and ovipositing females, which suggests that perching females are not engaged in reproduction. There is seasonal variation in egg number for the three categories in H. americana but not in A. anceps, which can be interpreted in terms of adaptive changes in egg production depending on female–male interactions in the former species but not in the latter species. There is no difference in PO activity among mating, ovipositing or perching females within either species, although measurements in December and March indicate distinct seasonal changes. Juvenile Hormone (JH) is known to reduce the effectiveness of the immune system by favouring the use of resources for reproduction. A possible role for JH is examined in H. americana, using the JH analogue methoprene to manipulate hormone activity, revealing that PO activity is reduced in methoprene‐treated H. americana females. Thus, although the results of the present study are indicative of possible hormone‐driven changes in PO, there is not necessarily a down‐regulation of immune function (as determined by PO activity) during mating or oviposition. The results complement some recent studies countering the idea that reproductive activities reduce the immune ability in insects.     

Resource density regulates the foraging investment in higher termite species

1. Resource density can regulate the area that animals use. At low resource density, there is a conflict in terms of balance between costs of foraging and benefits acquired. The foraging of the higher termite Nasutitermes aff. coxipoensis consists of searching throughout trails and a building galleries phase. 2. In this study, a manipulative field experiment was used to test the hypothesis that colonies of N. aff. coxipoensis forage towards a more profitable balance between the establishment of trails and gallery construction at low resource density. 3. The experiment was conducted in north‐eastern Brazil. Seven experimental plots were established with a continuous increase in resource density (sugarcane baits). Entire colonies of N. aff. coxipoensis were transplanted from their original sites to the experimental plot, totalling 35 nests. The number, branches and total length of trails and galleries were quantified. 4. The results show that N. aff. coxipoensis optimises its foraging output, intensifying the establishment of trails at the cost of gallery construction when resource density is low. The number of trails, the number of trail branches and the total length of trails decreased with increasing resource density. Interestingly, at low resource density, the search effort was concentrated on forming longer and a greater number of trails, a small proportion of which were converted into galleries. The opposite relationship was observed at high resource density. 5. These results suggest an optimisation of search efforts during foraging depending on resource density, a mechanism that may help researchers to understand the use of space by higher termite species.     

Reproductive biology of Cyrtopodium punctatum in situ: implications for conservation of an endangered Florida orchid

Cyrtopodium punctatum (Linnaeus) Lindley is an endangered epiphytic orchid restricted in the USA to southern Florida. This species has been extensively collected from the wild since the early 1900s, and today only a few plants remain in protected areas. As part of a conservation plan, a reproductive biology study was conducted to better understand the ecology of this species in Florida. Cyrtopodium punctatum relies on a deceit pollination system using aromatic compounds to attract pollinators. Nine aromatic compounds were identified as components of the fragrance of C. punctatum inflorescences, including two compounds that are known to be Euglossine bee attractants. However, this group of bees is not native to Florida. Of the four bee species observed to visit C. punctatum flowers in the present study, carpenter bees ( Xylocopa spp.) are likely to be the main pollinators. Pollination experiments demonstrated that C. puntatum is self-compatible, but requires a pollinator and thus does not exhibit spontaneous autogamy. In addition, the rates of fruit set were significantly higher for flowers that were outcrossed (xenogamy) than for those that were self-crossed. Thus, the species has evolved a degree of incompatibility. Examples of natural pollination and fruit set were observed during the present study (2007–2008), but the rates of reproduction were modest as a consequence of the low plant numbers and possible changes in insect densities as a result of anthropogenic influences.     

Effects of an experimental drought on the functioning of a cacao agroforestry system,Sulawesi, Indonesia

Agroforestry systems may play a critical role in reducing the vulnerability of farmers' livelihood to droughts as tree‐based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/Gliricidia stand over a 13‐month period. Soil water content was successfully reduced down to a soil depth of at least 2.5 m. Contrary to our expectations we measured only relatively small nonsignificant changes in cacao (?11%) and Gliricidia (?12%) sap flux densities, cacao leaf litterfall (+8%), Gliricidia leaf litterfall (?2%), soil carbon dioxide efflux (?14%), and cacao yield (?10%) during roof closure. However, cacao bean yield in roof plots was substantially lower (?45%) compared with control plots during the main harvest following the period when soil water content was lowest. This indicates that cacao bean yield was more sensitive to drought than other ecosystem functions. We found evidence in this agroforest that there is complementary use of soil water resources through vertical partitioning of water uptake between cacao and Gliricidia. This, in combination with acclimation may have helped cacao trees to cope with the induced drought. Cacao agroforests may thus play an important role as a drought‐tolerant land use in those (sub‐) tropical regions where the frequency and severity of droughts is projected to increase.     

Cytological evidence of natural hybridization in Brachiaria brizantha Stapf (Gramineae)

Two accessions of Brachiaria brizantha under cytological analysis showed 2 n  = 5x = 45 chromosomes. Pentaploidy probably resulted from natural hybridization between two species that were not closely related: an apomictic tetraploid male (2 n  = 4x = 36), and a sexual diploid female (2 n  = 2x = 18). The lack of affinity between genomes was clearly indicated by asynchrony during meiosis. The haploid genome ( n  = 9) showed unique behaviour, remaining univalent during prophase I and metaphase I, and undergoing sister-chromatid segregation and lagging at anaphase I. The laggard genome did not always reach the poles in time to be included in the telophase nucleus. However, when the inclusion was effective, this genome was distributed peripherally, changing the otherwise spherical nucleus shape. In the second division, the haploid genome behaved similarly, but as there was sister-chromatid segregation during the first division, the chromatids were slow to reach the poles, forming several micronuclei at telophase II. The two accessions were characterized as allo-autopentaploids, with the tetraploid genome (2 n  = 4x = 36) designated as B (from B. brizantha ) and the haploid genome as X, representing a species with a distinct genome having little affinity with the B genome. Thus, the hybrids' genome composition is represented by BBBBX. By comparing their meiotic behaviour with that observed in synthetic hybrids between B. brizantha and B. ruziziensis analysed previously, B. ruziziensis is the putative diploid sexual parent species in these pentaploid accessions.  © 2006 The Linnean Society of London , Botanical Journal of the Linnean Society , 2006, 150 , 441–446.     

Plasmodium falciparum Rhoptry Proteins of 140/130/110 kd (Rhop-H) Are Located in an Electron Lucent Compartment in the Neck of the Rhoptries

ABSTRACT. To investigate in more detail the structure of the high molecular weight rhoptry protein complex of Plasmodium falciparum, Rhop-H (140/130/110 kd), the complex was affinity purified from parasite extracts using rhoptry protein specific antisera prepared against Rhop-H proteins bound to and eluted from Balb/c mouse erythrocytes, using 0.5 M NaCl. The individual proteins (140 kd/Rhop-1, 130 kd/Rhop-2, and 110 kd/Rhop-3) were separated, electroeluted, and monospecific polyclonal antisera prepared against the individual proteins, and against the affinity purified complex. Immunofluorescence assays and immunoelectron microscopic studies were performed to verify the subcellular localization of the Rhop-H epitopes. Immunoblotting and immunoprecipitation assays were also performed. We report novel findings regarding the localization of the rhoptry proteins to an electron lucent compartment in the neck of the rhoptries. Analysis of the amino acid composition of the individually purified Rhop-H proteins demonstrated a predominance of negatively charged (E, D) as well as hydrophobic residues (L, A, P, S) in the three proteins. The percentage of negatively charged residues was high for all three proteins. Similarities in amino acid composition for the three proteins supports the previous data demonstrating shared properties such as erythrocyte and liposome binding, for the three proteins. Results of antibody characterizations using rhoptry protein specific antisera demonstrate the immunodominance of the Rhop-H complex.