Chronobiologic Aspects of a Coadaptive Process: The Interaction of Ludwigia elegans Flowers and Their More Frequent Bee Visitors

Field observations spanning 1 year of the visits of two bee species—Tet-raglossula bigamica (Hymenoptera: Colletidae) and Pseudagapostemon brasil-iensis (Hymenoptera: Halictidae)—to the flowers of Ludwigia elegans (Onagra-ceae) evinced the existence of circadian and circannual components in the rhythms of activity both of plant and bees. In addition to morphologic adaptations to the flower, the bees were temporally adjusted to each other and to the flower's opening and closing mechanisms. At the observation locality (Ribeirao Preto, São Paulo, Brazil—latitude 21 °-21 ° 30'S), the plant bloomed year-round. The flowers of the same population open simultaneously at the onset of the photophase, pollen and nectar being available almost immediately. Withering occurs in the afternoon of the same day. Although many bee species visited the flowers, T. bigamica and P. brasiliensis were the most frequent visitors, but their yearly rhythms were phased opposite to one another. Circadian rhythms were detected in pollen and nectar harvest. Comparisons of acrophases showed significant differences for males' and females' nectar collecting rhythm and for females' pollen harvest rhythm. As for the circannual component, acrophases of all rhythms occur at progressively later times from December to July when the migration is reversed until November. These data strongly suggest that the relationship between L. elegans and T. bigamica and P. brasiliensis is in accordance with a clearly temporal pattern and that the two bee species are temporally separated in nature.     

A new karyotype of Oligoryzomys (Sigmodontinae, Rodentia) from central Brazil

A new karyotype of the genus Oligoryzomys was described for specimens collected in Brazilian Cerrado in Tocantins and Goiás States. Conventional staining, G-, C-banding, and Ag-NOR staining techniques were used for describe this karyotype with 2n=70, AN=74 or 76. The chromosome complement, with the highest diploid number known among Oligoryzomys species, differs from all others previously reported. This small sized Oligoryzomys species can be differentiated from other Brazilian Oligoryzomys not only by chromosomal complement, but also in some morphological attributes. The new species is apparently restricted in distribution and endemic of Brazilian Cerrado, occurring only in Rio Tocantins basin.     

Is there a floral parasite mutualism in cycad pollination? the pollination biology of Encephalartos villosus (Zamiaceae)

Observations and experiments were carried out over 5 yr to distinguish between wind and insect pollination in the cycad Encephalartos villosus Lemaire (Zamiaceae). They were also designed to determine whether a pollination mutualism exists between E. villosus and Antliarhinus zamiae (Thunberg) (Coleoptera: Brentidae), an obligate ovule parasite that routinely parasitizes a large proportion of the ovules. The percentage of fertilized ovules dropped slightly when wind was excluded from the megastrobilus. However, when insects were excluded by either net bags or insecticide there was a substantial decrease in the proportion of fertilized ovules. Five beetle species belonging to four families were found on the strobili at the time of pollination. Using data on the effectiveness of pollen transfer to the receptive ovule, as well as data on abundance and pollen loads, a pollinator importance value (PIV) was determined for each beetle species and a pollinator importance index (PII) was determined for each population. PII values showed that an undescribed weevil (Porthetes sp., Curculionidae) was consistently the most important pollinator. A. zamiae and an undescribed beetle species within the Xenoscelinae (Languriidae) played a minor role in pollination, and their contributions varied from year to year and between populations. Two additional beetle species, Metacucujus goodei Endrödy-Younga (Boganiidae) and a second species of Xenoscelinae, had very low PII values and probably had little or no effect on pollination. Low PIV scores for A. zamiae were a result of its low numbers on the microstrobilus and the tendency of the beetles to remain on the outside of the megastrobilus. In the interaction between E. villosus and A. zamiae, the cycad does not appear to benefit significantly from a pollination service and I interpret this to mean that the relationship is antagonistic rather than mutualistic. There is, however, a possible mutualism between Porthetes sp. and E. villosus.     

Scent chemistry and pollinators in the holoparasitic plant Cynomorium songaricum (Cynomoriaceae)

• Holoparasitic plants are interesting heterotrophic angiosperms. However, carrion‐ or faeces‐mimicking is rarely described for such plants. There is no information on the pollination biology of Cynomoriaceae, despite the fact that these plants are rare and vulnerable. This is the first study to reveal pollination in a member of this family, Cynomorium songaricum, a root holoparasite with a distinctive and putrid floral odour.
• From 2016 to 2018, we studied the floral volatiles, floral visitors and pollinators, behavioural responses of visitors to floral volatiles, breeding system, flowering phenology and floral biology of two wild populations of C. songaricum in Alxa, Inner Mongolia, China.
• A total of 42 volatiles were identified in inflorescences of C. songaricum. Among these volatiles are compounds known as typical carrion scents, such as p‐cresol, indole, dimethyl disulphide and 1‐octen‐3‐ol. C. songaricum is pollinated by various Diptera, such as Musca domestica, M. stabulans (Muscidae), Delia setigera, D. platura (Anthomyiidae), Lucilia sericata, L. caesar (Calliphoridae), Wohlfahrtia indigens, Sarcophaga noverca, S. crassipalpis and Sarcophila meridionalis (Sarcophagidae). The inflorescence scent of C. songaricum attracted these pollinators. The plants significantly benefit from insect pollination, although wind can be a pollen vector in the absence of pollinators. C. songaricum is a cross‐pollinated, self‐incompatible plant.
• Our findings suggest that C. songaricum releases malodorous volatiles to attract Diptera to achieve pollination. This new example lays the foundation for further comparative studies in other members of this plant group and contributes to a better understanding of fly‐pollinated, carrion mimicking plants.

     

DNA extraction from bristles and quills of Chaetomys subspinosus (Rodentia: Erethizontidae) using a novel protocol

DNA extraction protocols are as varied as DNA sources. When it comes to endangered species, it is especially important to pay attention to all details that ensure the completion of the study goals and effectiveness in attaining useful data for conservation. Chaetomys subspinosus (Rodentia: Erethizontidae) is a secretive arboreal porcupine endemic to certain ecosystems of the Brazilian Atlantic Forest. A multidisciplinary study (including genetic data) was performed to create a management plan for the conservation of this species. Individuals from natural populations of the states of Bahia, Espírito Santo and Sergipe were sampled. To obtain a reliable and abundant amount of starting material, non-destructive methods were tested, extracting DNA from the bristles and quills that comprise most of this animal's hide. This method has also been innovative in adapting a DNA extraction protocol traditionally used for plants. Digestion using proteinase K was followed by protein precipitation with CTAB, a chloroform-isoamyl alcohol cleaning and DNA precipitation with isopropyl alcohol. This protocol supplies good-quality DNA for genetic analysis with molecular markers based on PCR.     

Description of the karyotype of Rhagomys rufescens Thomas, 1886 (Rodentia, Sigmodontinae) from Southern Brazil Atlantic forest

Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA(3) /DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA (3) /DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.     

Records of Coendou ichillus (Rodentia,Erethizontidae) from the Lower Urubamba Region of Peru

Coendou ichillus was first described in 2001 by Voss and da Silva, with a range from Amazonian Ecuador to Iquitos, Peru. Here, we describe an adult female Coendou ichillus specimen collected in a Tomahawk trap in the forest canopy of the Lower Urubamba Region of Peru in October 2013. We also describe pathologies and behaviors observed through 379 camera trapping photo events (2,196 photos) gathered in natural canopy bridges over the course of a year (7,198 trap nights), including information on activity period over the course of the day and over the course of the lunar cycle. We conservatively estimate that 17 individuals were photographed, including one juvenile. Being 900 km away from Iquitos, Peru (the site of the closest record), discovery of this species in the Lower Urubamba constitutes a significant range extension.     

An overview of the Bombus terrestris (L. 1758) subspecies (Hymenoptera: Apidae)

Bombus terrestris is one of the most abundant bumblebee species in the West-Palaearctic. Its widespread domestication results in the movement of many colonies. The aim of this paper is to describe the 9 subspecies currently recognised and to list some of their most obvious characteristics. Bombus terrestris is not declining anywhere, on the contrary, its synanthropic spread through domestication may be expected. However, its autumn and winter populations rely on a restricted choice of flowers so they may be threatened locally by scrub clearance and the destruction of their favourite autumnal flowers.     

Reproductive Biology of Erythrina falcata (Fabaceae: Papilionoideae)1

Reproductive phenology, floral biology, degree of self‐incompatibility, and floral visitors of Erythrina falcata were studied in an Argentinean population. Flowering occurs during the dry season from late August to late October. Flower lifetime is 5–6 d. Phylogenetic studies indicate that E. falcata, together with E. fusca and E. crista‐galli, are included in a basal clade within Erythrina. Its phylogenetic position, floral morphology, and nectar characteristics suggest a hummingbird–passerine mixed pollination system. The flowers are nontubular, and the vexillum (the upper petal of the corolla) covers the other remaining floral parts until displaced by a visiting passerine (Icterus cayanensis) or a hummingbird (Amazilia chionogaster). Both birds act as pollen vectors. Bees were observed as occasional pollinators. Nectar production begins at anther dehiscence and coincides with maximum stigmatic receptivity. The base of the keel forms a secondary nectar reservoir. Controlled pollinations showed that this species is self‐incompatible, although a few fruits develop from selfing. Pollen:ovule ratio (43,200:7) is as expected for a xenogamous plant. Only 1 percent of the flowers set seeds under natural conditions. Possible explanations for the low reproductive success are discussed.     

Reproduction of Byrsonima sericea (Malpighiaceae) in Restinga Fragmented Habitats in Southeastern Brazil

Habitat fragmentation may affect the reproductive success of plant populations in many different ways. Thus, negative, neutral, or positive plant responses can be observed, according to the balance of the different interactions. Variables related to mutualistic and antagonistic interactions (pollinator activity and gall occurrence, respectively) were measured on Byrsonima sericea populations of a fragmented seashore area ( restinga ) in southeastern Brazil. Pollinator visits to the oil-bearing flowers, insect gall occurrence on stems and inflorescences, and fruit set of B. sericea were compared between three small (up to 0.3 ha) and three large (14.0–99.0 ha) fragments. MANOVA showed differences between fragment classes. Nevertheless, a posteriori univariate ANOVA showed that the pollinator visit frequency was more than twofold higher in small fragments, and that gall occurrence and fruit set did not show significant differences between small and large fragments. These results suggest that the habitat fragmentation does not affect the female reproductive success of B. sericea in the studied restinga areas because resource availability seems to be a more important factor for fruit set than pollen limitation due to pollination failure. This is the first work assessing the effects of habitat fragmentation in restinga areas, which are intensely impacted by urbanization, so that no generalization about the fragmentation consequences can still be made for this ecosystem.     

Mimicry in hoverflies (Diptera: Syrphidae): a field test of the competitive mimicry hypothesis

Although most studies on the evolution of mimicry and warningcoloration in insects have considered predators as the majorselective force, it is possible that competition for food resourcescould also facilitate selection for these conspicuous signals.For example, when warningly colored social wasps visit flowers,then they frequently behave aggressively toward heterospecifics,and they also attack and feed on other flying insects. Underthese conditions, a resemblance to a wasp might provide a mimetichoverfly with improved access to floral resources by reducingthe frequency with which it is disturbed by other pollinators.We experimentally evaluated whether wasp-like colors and patternswere important in preventing other flower visitors from sharingthe same flower resource, using pairwise presentations of bothnatural and artificial prey in the field. Flower visitors weremore likely to visit unoccupied flowers compared with the flowerspinned with either natural or artificial specimens in 2 plantspecies with different inflorescences. However, flower visitorsdid not show a significantly reduced rate of visitation to flowerspinned with specimens bearing wasp-like colors and patternscompared with the flowers occupied by similar-sized specimensthat were nonmimetic. Overall, we found no compelling evidencein this study to support the contention that wasp-like warningsignals of hoverflies prevent other flower visitors from sharingflower resources, although insects showed a greater tendencyto avoid visiting flowers pinned with a wasp compared with flowerspinned with a nonmimetic fly.     

Patterns and implications of floral nectar secretion, chemical composition, removal effects and standing crop in Mandevilla pentlandiana (Apocynaceae)

Flower morphology, nectar features (chemical composition, production pattern, removal effects, and standing crop) and floral visitors are analysed in an Argentine population of Mandevilla pentlandiana. Nectar variability was examined during the lifetime of a single flower, over the course of the flowering season, and at different times of the day. Nectar is sucrose dominant. There were some variations in the proportions of sugar throughout both the flower lifespan and the flowering season. Flowers produced most nectar during bud-stage. Nectar secretion ceased near the end of the first day after flower opening. Nectar quantity varied as a function of flower age due to a combination of nectar secretion, cessation, and resorption periods. Overall sugar production was increased by nectar removal. Standing crop data showed that each open flower and inflorescence offers c. 2 and 11 mg of sugar respectively at any time of the flowering season. There was higher nectar availability at the beginning of the flowering season compared with the rest of the period. Flowers were visited by bumblebees, honeybees and hummingbirds. The greater the number of open flowers and the nectar variance, the more the mean reward quantity per flower available in the inflorescence. The sources of nectar variability in M. pentlandiana seem to be linked with both the female function (nectar resorption, nectar cessation) and the male one (early and comparatively large nectar availability, variation in nectar production as the flower ages, nectar secretion stimulation by nectar removals).     

Reproductive ecology of three endangered African violet (Saintpaulia H. Wendl.) species in the East Usambara Mountains, Tanzania

Knowledge of the reproductive biology of endangered plants is essential for their effective conservation. It also provides important information for understanding the evolutionary processes that affect speciation, thus helping the definition of proper units for conservation in endangered plants with problematic taxonomy. We studied the reproductive potential and possibility for hybridization in the endangered genus Saintpaulia (Gesneriaceae) by examining flowering phenology, flower and seed production and pollination of three sympatric cross‐compatible Saintpaulia species in the East Usambara Mts., Tanzania. The synchrony observed in flowering in S. confusa and S. difficilis may enable hybridization between these two species, whereas partial phenological separation may contribute to the integrity of S. grotei. Although the level of flower abortion is high in S. confusa, each pollinated flower yields about 1000 seeds. Saintpaulia confusa produces fruits following both self‐ and cross‐pollination but spontaneous self‐pollination seems not to occur. Thus, seed production depends on sufficient pollinator service. Floral heteromorphy (i.e. enantiostyly) and bee pollination are likely to further enhance cross‐pollination, suggesting that the genus predominantly outcrosses. Thus, Saintpaulia populations are likely to suffer from negative effects of inbreeding if they become small and isolated.     

The Impact of Tooth Wear on Occlusal Shape and the Identification of Fossils of New World Porcupines (Rodentia: Erethizontidae)

Although isolated dental remains are a central source of data in mammalian paleontology, the teeth of many taxa remain unidentifiable at low taxonomic levels because of intraspecific variation. Extant New World porcupines, Erethizontinae, illustrate this problem. Since being declared unusually variable over 50 years ago, molar occlusal morphology has been neglected as a potential source of diagnostic traits. Here, we use geometric morphometrics to re-evaluate the occlusal morphology of the third lower molar of erethizontines as the basis for identification of genera while accounting for variation, particularly changes in shape caused by progressive tooth wear. We model the impact and predictability of this source of variation by using CT-based digital sectioning. We use modelled occlusal shapes to analytically search for traits that can be used to improve identification of isolated dental remains, as well as training machine-learning models to assign occlusal surfaces to genus. Nearly half of all shape variation can be explained by variables such as wear and size. Resulting models of shape predict six univariate traits that may diagnose the two extant genera, especially when specimens are compared at the same wear stage. However, high levels of variation previously noted qualitatively also influence quantitative analyses, rendering machine learning models unreliable. Overall, although the identity of some specimens that are highly worn or contain certain combinations of traits will remain ambiguous, large segments of the gnathic erethizontine fossil record have renewed utility when analyzed using these methods.

     

Pollination and Breeding System of Vellozia squamata (Liliales: Velloziaceae): A Species of the Brazilian Cerrados

The pollination biology and breeding system of Vellozia squamata (Velloziaceae), a species of cerrado vegetation in Central Brazil, were studied. V. squamata is unusual in being pollinated by a few, generalist bee species despite having very large flowers, and having a distinctive pulsed flowering phenology. The species is self-incompatible but with a late-acting, post-fertilization rejection mechanism.     

Flies and concealed nectar sources: morphological innovations in the proboscis of Bombyliidae (Diptera)

Bee-flies (Bombyliidae) have morphological adaptations of the mouthparts to particular floral traits. To investigate this the short, plesiomorphic proboscis of Hemipenthes morio was compared with the long, apomorphic proboscis of Bombylius major . A novel feeding position enables B. major to use flowers that open to the side as additional nectar sources. The new horizontal feeding position is enabled by the prolonged ventral base of the proboscis. Bombylius major exploits deep corolla tubes with an elongate proboscis, and an increased efficiency in both the suction pumps and the sealing mechanisms of the proboscis. The exploitation of narrow corolla tubes is made possible by the shift from a sponging feeding mode, exhibited by H. morio , to the exclusively sucking mode in B. major . Besides quantitative changes in the proportions of the different proboscis components, labellar movements as well as the structures of saliva distribution are changed along with this shift. The labial musculature of B. major does not significantly differ from the plesiomorphic state, since both examined species do not only feed on nectar, but also on pollen.