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Vanilla phaeantha in a gallery forest in the region of Araguari, Minas Gerais State, Brazil. (a) Overview, showing the hemiepiphyte growing on a phorophyte, from soil level up to 5 m. (b) Detail of the phorophyte adhering roots (arrows). (c) Detail of the terrestrial roots (arrows). (d) Detail of the free roots in their initial stages of development (arrow)
Detail of the epidermis and protein contents of Vanilla phaeantha roots (Orchidaceae). Scanning electron micrograph demonstrating details of the epidermis of the free roots (a), root adhering to the phorophyte (b), and fixed in the soil (c). (d) Transversal section of the free root, demonstrating the exodermis and simple epidermis with live cells at maturity (positive reaction for proteins are indicated by a blue/green color — arrows). (e) Transversal section of the root in contact with the phorophyte, showing a simple epidermis with conspicuous cellular contents. (f) Transversal section of a root fixed to the substrate, showing the cortical parenchyma infested with mycorrhiza (proteins are indicated by a blue color). Ep = Epidermis; Ex = Exodermis and Co = Cortex
Internal structure of the roots of Vanilla phaeantha (Orchidaceae) growing under different conditions. (a, b and c) Transversal sections of the totally free aerial roots: (a) general view of the root with many aerenchyma lacunae (*), (b) detail of the epidermis showing light impregnations with lipidic substances, (c) detail of the lightly lignified epidermis and more conspicuous fluorescence (more lignin) in the exodermis. (d and e) Transversal sections of the growing roots adhering to the phorophyte; (d) General view demonstrating the epidermis with root hairs (arrows) in contact with the substrate, and aerenchyma lacunae (*), and (e) detail of the lightly lignified epidermis and a more conspicuous fluorescence (more lignin) in the exodermis. (f and g) Transversal sections of the terrestrial roots; (f) Less developed aerenchyma lacunae (*), and root hairs around the entire root, (g) detail of the lightly lignified epidermis. Staining for lipids (Sudan), and lignin (DAPI filter). Ep = Epidermis; Ex = Exodermis; Co = Cortex; VC = Vascular cylinder; and Rh = Root hairs
Presence of lipids and lignin in the root tissues of Vanilla phaeantha (Orchidaceae). (a and b) Lipidic impregnations in the exodermal cells of the (a) roots adhering to the phorophyte and (b) roots fixed to the soil. (c) Lignified exodermis and passage cells in the contact region between the phorophyte (arrows) and the adhering roots. (d) Detail of the lignified Casparian strip cells of the endodermis (arrow) of free roots. (e, f and g) Detail of the endodermis with lipidic impregnations in (e) roots adhering to the phorophyte and (f and g) roots fixed to the soil. (h and i) Endodermal cells showing the presence of lignin (arrow) in (h) roots fixed to the soil and (i) roots adhering to the phorophyte. Staining for lipids (Sudan), and lignin (DAPI filter). Ex = Exodermis; En = Endodermis; PC = passage cells; Co = Cortex; Cs = casparian strips; VC = vascular cylinder; Xy = Xylem
The aerial environment appears to structurally modify roots, which frequently show specializations for absorbing water and nutrients. Among those specializations are the velamen, a multiseriate epidermis generally composed of dead mature cells, and greater degrees of lignification in the endodermis, exodermis, and pith. Vanilla phaeantha is a hemiepiphyte used here as a model of study to determine which root characteristics demonstrate the most plasticity in response to aerial and terrestrial environments. It produces roots growing under three conditions: (1) aerial and free, growing from the highest branches towards the ground; (2) aerial roots attached to the phorophyte; and (3) terrestrial. Samples taken 3 cm from the apices were used to prepare histological slides. The tissues and other anatomical structures were measured and histochemically characterized. The most plastic characteristics were the external periclinal thicknesses of the exodermis and the total area occupied by the aerenchyma lacunae. The free roots were the longest, did not evidence root hairs, and had the largest number of the aerenchyma lacunae; they also evidenced greater thicknesses of the exodermis in contact with the epidermis walls that helped maintain their shapes. Terrestrial roots had root hairs around the entire circumference and intense infestations of mycorrhiza, indicating their involvement in nutrient acquisition. The adhering roots evidenced free regions similar to those of aerial roots, as well as adhering regions showed characteristics similar to terrestrial roots (with root hairs and mycorrhiza infestations).
Insects and fungi are abundant in many environments, in which facultative and/or obligate associations involving these groups have been established during evolution. In termites, mutualism with fungi is well reported for some termite lineages (e.g., Macrotermitinae). Within some subterranean termite species (Rhinotermitidae), egg-mimicking fungi, also referred to as “termite “balls”, are often harbored inside the nest, mixed to the egg piles. Such interaction seems to be advantageous for both partners since the fungi are protected inside the nest while they may serve as an additional food source and also provide cellulases which may be incorporated into the termite digestive process. Although such mutualism has been reported for seven species of Reticulitermes and Coptotermes formosanus, all the samplings were restricted to temperate regions. Here, we provide the first Neotropical record of this termite-fungus association, and the first report for Coptotermes gestroi. The morphological characters of the “termite balls” observed in a C. gestroi nest resemble those already reported for Reticulitermes spp. and the congeneric species C. formosanus. They include a color ranging from light to dark brown, spherical shape, and a reduced diameter (0.23–0.34 mm). Our findings provide new insights into the geographical distribution of the association between termites and sclerotium-forming fungi. Future genetic analyses will be valuable aiming to identify the egg-mimicking fungi associated with C. gestroi and shed light on the evolution of this fascinating symbiosis.
Experimental setup and experimental stimuli: a positioning of speakers (A, B, C, and D) under leaf litter covered mesh platforms, human observer, and bat (not to scale) within the flight cage. Black letters show one of three possible distances for each playback stimulus, and gray letters show the other two distances. b The four experimental treatments. Complex, “whine-chuck” túngara frog calls, represented in the figure by simplified waveforms, were played from a starting speaker until the bat took flight, and then one more call was played from the same speaker (SS), no additional calls were played (SN), or a new call was played from a location 1 or 3 m away (S1 and S3). When call locations were switched, new calls were always played at the same distance from the roost
Attack effectiveness of bats (N = 14) in response to acoustic stimuli varying in the presence and relative spacing of additional frog calls played mid-flight. Responses where bats switched to attack calls spaced 1 m (n = 133 trials) and 3 m (n = 78 trials) from pre-flight calls are displayed separately from responses where bats attacked the source of the pre-flight call (1 m, n = 37 trials; 3 m, n = 64 trials). Shown are a means of mean localization errors exhibited by each bat. b Means of mean attack flight latencies exhibited by each bat and c means of mean rate of successful food retrieval exhibited by each bat
While foraging, eavesdropping predators home in on the signals of their prey. Many prey signal from aggregations, however, and predators already en route to attack one individual often encounter the signals of other prey. Few studies have examined whether eavesdropping predators update their foraging decisions by switching to target these more recently signaling prey. Switching could result in reduced localization errors and more current estimates of prey location. Conversely, assessing new cues while already in pursuit of another target might confuse or distract a predator. We tested whether fringed-lipped bats (Trachops cirrhosus) switch prey targets when presented with new cues mid-approach and examined how switching and the distance between simulated prey influence attack accuracy, latency, and prey capture success. During nearly 80% of attack flights, bats switched between túngara frog (Engystomops pustulosus) calls spaced 1 m apart, and switching resulted in lower localization errors. The switching rate was reduced, and the localization advantage disappeared for calls separated by 3 m. Regardless of whether bats switched targets, attacks were less accurate, took longer, and were less often successful when calls were spaced at larger distances, indicating a distraction effect. These results reveal that fringed-lipped bats attend to cues from non-targeted prey during attack flights and that the distance between prey alters the effectiveness of attacks, regardless of whether a bat switches targets. Understanding how eavesdropping predators integrate new signals from neighboring prey into their foraging decisions will lead to a fuller picture of the ways unintended receivers shape the evolution of signaling behavior.
Epistemological differences between prescriptive and proscriptive views of adaptation
Since Darwin’s theory of evolution, adaptationism is frequently invoked to explain cognition and cultural processes. Adaptationism can be described as a prescriptive view, as phenotypes that do not optimize fitness should not be selected by natural selection. From an epistemological perspective, the principle of a prescriptive definition of adaptation seems incompatible with recent advances in epigenetics, evolutionary developmental biology, ethology, and genomics. From these challenges, a proscriptive view of adaptation has emerged, postulating that phenotypes that are not deleterious will be evolutionary maintained. In this epistemological investigation, we examine how the shift from adaptationism to a proscriptive view changes our view of cognition and culture. We argue that, while adaptationism leads to cognitivism and a view of culture as strategies to optimize overall fitness, the proscriptive definition favors embodied theories of cognition and a view of culture as the cumulative diffusion of behaviors allowed by the constraints of reproduction.
Tactile perception is involved in a variety of contexts (adaptations to climatic conditions, protection of the body against external dangers…) and is as important as the other sensory modalities for the survival of an individual. This tactile modality has been particularly well studied in humans, revealing high individual variations modulated by a variety of intrinsic and extrinsic factors such as age, sex, pathological disorders, or temperament. Tactility is also involved in animals’ social lives, although there are disparities between species. For example, social tactile contact among horses is limited, but this does not mean that they do not react to tactile stimuli but rather with their very thin skin they are able to detect minute stimuli (although they respond more to larger stimuli). Despite a fairly large effort to characterize it, there are controversies concerning equine tactile sensitivity. In this review, we examine studies that have used the same tool (von Frey filaments) and try to disentangle what could explain the differences observed. It appears that many aspects are poorly known or controversial and that the procedures may be so different that the results of different studies cannot be compared. We went further by testing tactile reactivity of a population of unridden horses and found that four factors influenced their tactile reactivity (type of horse, filament size, body area, time of day). These results could explain some of the discrepancies observed in the literature and suggest, in particular, that more attention should be paid to the context of the test.
A Geographic location of the Cañadón Pelado area in western Chubut Province (Argentina). B Schematic map of the Cañadón Pelado area, showing the main geological units in the studied area, and the local stratigraphic column. C SE looking profile showing main units with rock and fossil samples. Abbreviations: N, Notopithecus level; P, Propyrotherium level; V, vehicle as scale
Propyrotherium saxeum. LIEB-PV 3200: A–C left mandible fragment with p3–m3 in lateral (A) and medial (B) views, and schematic lineal drawing (C); D–G right mandible fragment, preserving m2–m3 in medial (D), dorsal (E), anterior (F), and posterior (G) views. Abbreviations: alo, anterior lophid; ang. pr, angular process; cc, coronoid canal; cor. pr, coronoid process; cond, mandibular condyle; fo, foramen; HAR, height ascending ramus; inc. md, incisure mandibular; L, length; LHR, length of the preserved portion of the horizontal ramus; LAR, length of the ascending ramus; m. fos, masseteric fossa; md. fo, mandibular foramen; m. tem. tub, tuberosity for m. temporalis; plo, posterior lophid. All scale bars represent 20 mm (C, E–G, not at scale)
Propyrotherium saxeum. A–J LIEB-PV 3200: A–C symphysis preserving the left tusk-like incisor alveolus and part of the right ramus with p3–4 and tusk-like incisor alveolus in dorsal (A), ventral (B), and anterior (C) views; D–G fragment of left i2? in lateral (D), dorsal (E), anterior (F), and posterior (G) views; H–J left mandible with p3–m3 in anterior (H) and occlusal (I) views (J, schematic lineal drawing). Abbreviations: cor. pr, coronoid process; cr, cristid; cre, crenulations; cro, cristid obliqua; dcd, distal cingulid; en, enamel; etcd, entoconid; etfd, entolophid (= posterior lophid); hpcd, hypoconid; inc. al, incisor alveolus; lbcd, labial cingulid; lbtb, labial tubercle; lgtb, lingual tubercle; mcd, mesial cingulid; mtcd, metaconid; mtfd, metalophid (= anterior lophid); pl-pa, paralophid-paraconid; prtd, protoconid. *Indicates the narrowness of the mandibular bone in front of the p3, just where the anterior border of the symphysis and the tusk alveolus are placed. Arrow (in D, E) indicates anterior end of incisor. All scale bars represent 20 mm (B, C, F–H, not at scale)
Propyrotherium saxeum. A-B MACN-A 10929 (paralectotype), left lower cheek tooth (p4?), in occlusal and labial views. C–D, LIEB-PV 3201, right m1 in occlusal and labial views. E–I LIEB-PV 3208, left P2, in occlusal (E), ventral (F), labial (G), lingual (H), and distal (I) views. J–K LIEB-PV 3202, right P3, in occlusal and mesial views. L–M MACN-A 10929 (lectotype), left P4, in occlusal and lingual views. Abbreviations: cre, crenulations; cro, cristid obliqua; crt, crest; lgc, lingual cingulum; lbtb, labial tubercule; lgtb, lingual tubercle; mc, mesial cingulum; P2fc, facet for P2. Arrows show mesial side. All scale bars represent 20 mm
The consensus tree (TBR = 46; CI = 0.72; RI = 0.62) obtained from the two most parsimonious trees yielded from the cladistics analysis. Synapomorphies are shown above rami, while support values and nodal support appear below rami. Letters a, b, and c indicate nodes, which are explained in the text
Pyrotheria is one of the most peculiar orders of South American native ungulates, whose members evolved from the early? Eocene to the late Oligocene period when they became extinct. Here, we described the most complete specimen of Propyrotherium saxeum ever found, one of the lesser-known representatives of pyrotheres that characterized the middle-late Eocene period of Patagonia (Argentina). It includes a nearly complete mandible and a tusk-like tooth of the same individual, as well as other isolated upper and lower teeth. Propyrotherium saxeum has a dental formula that includes at least P2–M3 and i2?–p3–m3 (lack of p2). It is characterized by some peculiar features of the mandible (e.g., ascending ramus longer than high, hiding the m3 and straight incisura mandibular) and dentition (e.g., cristid obliqua in p3–m3, cristid between posterior lophid and distal cingulid in m1–m3, P3–M3 and p3–m3 bilophodont, P2 and p3–m3 bi-rooted, P3–M3 three-rooted, paraconid in p3). The phylogenetic analysis reveals that Propyrotherium is more closely related to Pyrotherium and Baguatherium, differing from the previous hypothesis, and supports the monophyly of Pyrotheriidae including Carolozittelia, Griphodon, Pyrotherium, Baguatherium, and Propyrotherium. The absolute age obtained through U–Pb zircon dating of the Sarmiento Formation at Cañadón Pelado, the fossil’s original locality, indicates that the fossil-bearing tuff would have been deposited between 39.65 and 40.41 Ma, with a weighted mean age of 40.03 ± 0.38 Ma (Bartonian). This implies a biochron much longer than previously thought for Propyrotherium and provides a chronological framework for the fauna of Cañadón Pelado.
Many small pelagic fishes obligately form schools; some of these schools reach remarkable sizes. Although the school is a fundamental and important ecological unit and is the site of biological interactions such as competition and predation, information on schooling processes in the field remains scarce. Here, we examined the quantitative relationships between population density and school size, the number of schools, and other school characteristics (i.e. packing density, volume, and cross-sectional area) in three species of small pelagic fishes: Japanese anchovy Engraulis japonicus, Japanese sardine Sardinops melanostictus, and chub mackerel Scomber japonicus. We found that school size increased almost linearly with population density, whereas the number of schools and other characteristics increased non-linearly with population density, whereby the rate of increase slowed radically as population density increased. These results indicate that, at low population densities, an increase in density causes an increase in both school size and the number of schools, whereas at higher population densities, an increase in density triggers the formation of larger schools rather than more schools. Furthermore, we found that the shapes of the relationships of all school characteristics with population density differed amongst species. Our results indicate that the schooling behaviour of small pelagic fishes is density-dependent, and responses to changes in density are species-specific. Our results provide insight into how biological interactions such as intra- and inter-specific competition and predator–prey interactions mediate the density-dependent processes that underlie the population dynamics and community structure of small pelagic fishes in marine ecosystems.
Ikaite is the calcium carbonate hexahydrate (CaCO3·6H2O), which precipitates below ~ 7 °C, first identified from Ikka Fjord in southwest Greenland and subsequently more widely reported. Here is described the serendipitous discovery of ikaite on a tree (Populus fremontii) wound from the hot Sonoran Desert, which precipitates during short cold periods in the winter, whereas monohydrocalcite forms through most of the year. The tree wound consists of infected wood, called wetwood that exudes a nutrient-rich water on which a jelly-like slime flux forms. Ikaite, along with alpha sulfur, precipitates in and on the bacterial slime flux jelly. Each tree wound occurs as an island of mineralization: all the elements for the mineral formation are supplied through the xylem sap expressed from the wetwood infection. The P. fremontii wetwood is capped and surrounded by a hard mineralized zone dominated by ikaite/monohydrocalcite, alpha sulfur, and a range of carbonates and sulfates, on which the slime flux jelly occurs. Water oozing from the wetwood is modestly alkaline (pH = 8.34), with elevated concentrations of K+ (5554.7 ppm) and S as SO42− (1662.9 ppm), with Ca2+ (151.9 ppm) and Mg2+ (270.3 ppm). This water chemistry favors the precipitation of ikaite/monohydrocalcite, both within and below the jelly. The ikaite is temperature sensitive, though the laboratory results show that it can persist for several days at room temperature in the sulfur-rich jelly. The ikaite, and associated mineralization within and around the slime flux jelly, illustrates a new, and likely, global form of bio-mediated mineralization.
The function of flower orientation is much debated, with adaptation to pollinator mouthparts being a particularly compelling explanation, but also one that has lacked empirical support from broad-scale comparative studies. The two families of long-proboscid fly pollinators show similar hovering behaviour while feeding on nectar but differ in the biomechanics of their proboscides which can be up to 80 mm in length: Tabanidae have a fixed forward-pointing proboscis while Nemestrinidae can swivel their proboscis downwards. We predicted that this difference has implications for the evolution of flower orientation. We established the flower angles of 156 South African plant species specialised for pollination by long-proboscid flies. Using a phylogenetically corrected analysis, we found that flowers pollinated by Tabanidae tend to be horizontally orientated, while those pollinated by Nemestrinidae tend to be more variable in orientation and more often vertically orientated. These results confirm the importance of pollinator biomechanics for the evolution of floral traits and highlight a potential mechanism of reproductive isolation between sympatric plant species pollinated by different long-proboscid fly families.
Ring recoveries of Common Woodpigeons Columba palumbus with breeding sites in Germany spending the wintering period outside of Germany. a Validated ring recoveries are represented as a line between ringing and recovery site. Different colours correspond to the respective country in which the wintertime was spent. b Line density kernels for Woodpigeon ring recoveries. Kernel densities of ring recovery positions outside of Germany during the non-breeding period are displayed as dashed line (50% kernel) and dotted line (95% kernel). Background colours indicate the terrain (Background map: Stamen terrain (map tiles by Stamen Design:; data by OpenStreetMap:
Migratory movements of Common Woodpigeons Columba palumbus equipped with Argos-transmitters (n = 12) during the winter season in Portugal and France (dark blue lines and symbols) or during the breeding season with GPS-GSM transmitters (n = 4) in Hesse, Germany (pink lines and symbols). The map gives the spatial organization with spring migration (solid line) and autumn migration (dashed line) between the breeding sites (circles) and the winter sites (squares). The star symbol indicates that breeding and winter time in at least 1 year were spent at the same location. Crosses indicate that the last position was transmitted outside the breeding or winter site. The insets show the temporal organization with percentages of time for period spent at the breeding site (dark grey), the non-breeding site (light grey) and on migration (striped = spring migration; dotted = autumn migration) and average arrival and departure for each respective period. Background colours indicate the terrain (Background map: Stamen terrain (map tiles by Stamen Design:; data by OpenStreetMap:
Average proportions of land cover categories in monthly home ranges used by tagged Common Woodpigeons Columba palumbus. Shown are Woodpigeons from two regions (Lisbon, Portugal, n = 10 and Giessen, Germany, n = 19). The different wintering strategies of individuals from Giessen are shown separately for the wintering period: residents (no symbol), individuals using another distinct site during the winter than during the breeding season, but migratory movements occurred within Germany (black circle symbol), and Woodpigeons migrating to France (black triangle symbol). Categories occurring with < 1% were combined into ‘Others’. Land cover categories and associated colours were chosen according CORINE land cover (CLC) nomenclature. Black lines represent the average proportion of the land cover main categories ‘Artificial surfaces’ (continuous line) and ‘Agricultural areas’ (dashed line). Sample sizes and detailed proportions can be found in Table S3
Foraging behaviour of Common Woodpigeons Columba palumbus (n = 19) with breeding sites in the city of Giessen, Hesse (n = 19). Left: Circular diagram showing the proportion of individuals (0–100%) leaving the city area, i.e. artificial surfaces, to forage outside the city on agricultural used areas. Foraging outside was assumed if parts of the home range (95% Kernel Utilization Distributions KUD) were located on agricultural areas outside the city area. Right: The circular diagram represents the direction (geographic North N corresponds to 0°) and distance (0–20 km) Woodpigeons flew from the city of Giessen to foraging sites outside the city area. Each data point indicates the orientation of one individual bird for its monthly 95% KUD. Arrow indicates the mean direction (α) and vector length (r; * p < 0.001, Rayleigh test). Symbols used as in Fig. 3
Individual information of Common Woodpigeons Columba palumbus equipped with Argos transmitters during the wintering period in France and Portugal
Migration is used by many species as a strategy to deal with a seasonally changing environment. For some species, migration patterns can vary across different or even within the same breeding area. The Common Woodpigeon Columba palumbus , an abundant and widespread Palearctic species, exhibits three migratory strategies (strictly migratory, partially migratory and resident) across its European breeding grounds. Based on ring recoveries and satellite tracking data, we investigated the migration and foraging behaviour of Woodpigeons breeding in Southwestern Europe (Portugal) and Central Europe (Germany). We found that individuals could be classified as residents (Portugal) or partial migrants (Germany), with migrating individuals following the European sector of the East Atlantic flyway, and mainly wintering in France. In addition to general data on migration phenology, we provide evidence for different migration strategies (migration of varying distances or resident behaviour), low wintering site fidelity and the use of multiple wintering sites. Furthermore, tracking data provided information on migratory behaviour in consecutive years, clearly showing that individuals may switch migratory strategies (resident vs. migrant) between years, i.e. are facultative partial migrants. While individuals from Portugal mainly stayed within a large park (‘green urban area’) year-round, Woodpigeons from the city of Giessen (Germany) regularly left the urban area to forage on surrounding farmland (with an average distance covered of 5.7 km), particularly from July to September. Overall, our results highlight the behavioural plasticity in Woodpigeons in terms of foraging and migration strategies within and amongst individuals as well as populations.
Records of chondrichthyan egg capsule morphotypes from the paralic deposits of the Belgian Coal Measures Group (Pennsylvanian; Bashkirian–Moscovian; Namurian B–Westphalian B according to the traditional subdivision) are presented and discussed. These include several species of the hybodontiform type Palaeoxyris as well as the putative holocephalian types Vetacapsula and Crookallia. Furthermore, the type specimens of Scapellites cottoni and S. minor, two additional putative and enigmatic egg capsules from the same lithostratigraphic unit, are figured and discussed. Altogether, a highly diverse egg capsule assemblage documented from the Belgian deposits implies the presence of at least eleven different Carboniferous chondrichthyan species using the ancient aquatic environments for spawning and as nurseries. The absence of the xenacanthiform morphotype Fayolia, known from surrounding coeval Coal Measures areas of northern France, the Netherlands, and Germany, is conspicuous. This lack may be a result of collecting bias and does not reflect a real pattern.
The relationship between eDNA concentration and fish abundance, based on the aquarium samples from Jo et al. (2020). The abbreviation “Adj.R²” indicates R² values adjusted by the degrees of freedom. The upper and lower panels represent linear regressions for mt- and nu-eDNA, respectively, and the two left panels represent linear regressions when pooling temperature levels. Amplicon sizes of mt- and nu-eDNA were 127 and 164 bp, respectively
The relationship between eDNA concentration and fish abundance, based on the mesocosm samples (a) and pond samples (b) from Minamoto et al. (2017). The abbreviations “Adj.R²,” “Cond.R²,” and “Marg.R²” indicate the R² values adjusted by the degrees of freedom, conditional R² values considering the variance of both fixed and random effects, and marginal R² values considering only the variance of the fixed effect, respectively. Amplicon sizes of mt- and nu-eDNA were 78 and 84 bp, respectively
The relationship between zebrafish eDNA concentration and the number of individuals across target genetic regions. The plot type represents the type of eDNA marker (circle: mt-eDNA, triangle: multi-copy nu-eDNA, square: single-copy nu-eDNA). The abbreviation “Adj.R²” indicates the R² values adjusted by the degrees of freedom. Amplicon sizes of mt-, multi-copy nu-, and single-copy nu-eDNA were 132, 128, and 125 bp, respectively
Comparison of R² values between mt- and multi-copy nu-eDNA analyses by synthesizing the results estimated in the present study. Plots and error bars represent mean values and their standard deviations. Numerals in parentheses indicate the number of individual R² values required for each plot
Comparison of eDNA decay rate constants under different temperature and pH conditions. Plot and error bars represent mean values and their 95% confidence intervals (CIs). CIs were estimated using the confint function in R
Environmental DNA (eDNA) analysis is a promising tool for the sensitive and effective monitoring of species distribution and abundance. Traditional eDNA analysis has targeted mitochondrial DNA (mtDNA) fragments due to their abundance in cells; however, the quantification may vary depending on cell type and physiology. Conversely, some recent eDNA studies have targeted multi-copy nuclear DNA (nuDNA) fragments, such as ribosomal RNA genes, in water, and reported a higher detectability and more rapid degradation than mitochondrial eDNA (mt-eDNA). These properties suggest that nuclear eDNA (nu-eDNA) may be useful for the accurate estimation of species abundance relative to mt-eDNA, but which remains unclear. In this study, we compiled previous studies and re-analyzed the relationships between mt- and nu-eDNA concentration and species abundance by comparing the R² values of the linear regression. We then performed an aquarium experiment using zebrafish (Danio rerio) to compare the relationships across genetic regions, including single-copy nuDNA. We found more accurate relationships between multi-copy nu-eDNA and species abundance than mt-eDNA in these datasets, although the difference was not significant upon weighted-averaging the R² values. Moreover, we compared the decay rate constants of zebrafish eDNA across genetic regions and found that multi-copy nu-eDNA degraded faster than mt-eDNA under pH 7, implying a quick turnover of multi-copy nu-eDNA in the field. Although further empirical studies of nu-eDNA applications are necessary to support our findings, this study provides the groundwork for improving the estimation accuracy of species abundance via eDNA analysis.
Arthropods with a pair of mandibles (Mandibulata) emerged by the end of the Cambrian period. The mandible is one of the apomorphic characteristics of this monophyletic clade, which is composed of Pancrustacea and Myriapoda. Acquisition of the mandible is one of the important events of the evolutionary pathway of arthropods because the powerful masticatory system provides benefits to individuals regarding food selection. Ancestral mandibulates are well known as so-called Cambrian bivalved arthropods, and a few of them provide a pair of valid mandibles with a broad molar process. However, extant bivalved arthropods can only be found in a few lineages of crustaceans, though all of them are equipped with mandibles. This study focuses on the neuroanatomy of the mandibular skeleto-muscular system of Heterocypris incongruens (Ostracoda, Crustacea), a millimeter-sized bivalved crustacean. Electron microscopy reveals that numerous mechanoreceptive sensilla are distributed inside the mandibular gnathal edges and that there are two types (heterodynal and monodynal) of sensilla, which differ in the number of dendrites and their probable function. This sensory nervous system in the gnathal edges contributes to the precise interdigitation of the right and left mandibles to allow for powerful omnivorous mastication, and the mandibular interdigitation plays a role as the fulcrum of triggering action to open the valves. Therefore, by reversing its fulcrum and load, the mandibular skeleto-muscular system in podocopid ostracods has two sub-systems with different functions, namely the "mandibular masticatory system" and the "valve opening system." Furthermore, this investigation provides significant information on the feeding mode of Cambrian bivalved arthropods, from the view of the functional morphology of the mandibular skeleto-muscular system.
Extrafloral nectary plants from a Brazilian tropical savanna. aAncistrotropis firmula, bBionia coriacea, cCochlospermum regium, and dPeixotoa tomentosa. The arrows indicate the location of extrafloral nectaries
Production of flower buds in four extrafloral nectaried plants — aAncistrotropis firmula, bBionia coriacea, cCochlospermum regium, and dPeixotoa tomentosa — according to the absence and presence of ants, and time of sampling. The miniature figures show the cumulative number of flower buds. The figure shows the median, quartiles, and the maximum and minimum values. Statistical results depicted in Tables 2 and 4
Number of fruits in four extrafloral nectaried plants — aAncistrotropis firmula, bBionia coriacea, cCochlospermum regium, and dPeixotoa tomentosa — according to the absence and presence of ants, and time of sampling. The figure shows the median, quartiles, and the maximum and minimum values. The miniature figures show the cumulative number of flower buds. Statistical results depicted in Tables 3 and 4
Plants provide extrafloral nectar, which is a food resource taken by ants, especially aggressive species that may act as plant guards. To our knowledge, no study has been conducted to concurrently investigate the fluctuation of plant fitness over its whole reproductive season, recording and comparing both short periods (different samplings during the plant's reproductive season) and the season/pooled data (all fruits produced during the reproductive season). Here, by assigning plants to either ant-present or absent treatments, we investigated the influence of the protective foliage-dwelling ant, Camponotus crassus, on the flower bud and fruit production of four extrafloral nectaried plants (Ancistrotropis firmula, Bionia coriacea, Cochlospermum regium, and Peixotoa tomentosa) throughout their annual reproductive season. Periodic samples in the field revealed a large variation in plant reproduction throughout the season; the increases in buds and fruits were not constantly higher in plants with ants, and in fact, plants without ants had more reproductive structures sometimes. Nonetheless, the examination of the pooled data, i.e., cumulative number of flower buds and fruits produced during the reproductive season, revealed the plants with ants produced more flower buds and fruits (e.g., up to twofold greater in A. firmula) compared to ant-absent treatments. Our results indicate the effects of ants on plant reproduction are not constant over time, but the net benefits to plants with ants are reflected in increased fruit production. Therefore, the investigations of the benefit of ants on plants should consider the whole plant's reproductive season rather than single samplings within plant reproduction period.
Mean environmental temperature and mean environmental precipitation at the nearest meteorological station to the study site by month
Body condition (a) and body mass (b) of Sceloporus torquatus by sex and season. Letters show differences by season for the same sex. Numbers show differences by sex during the same season. Values are mean ± SE
Inflammatory response of Sceloporus torquatus by sex and season. Since we did not find differences by sex, the letters show differences by season. Values are mean ± SE
Intensity of mite infestations in Sceloporus torquatus by sex and season. Letters show differences by season for the same sex. Numbers show differences by sex during the same season. Values are mean ± SE
We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles. Other studies have used many species with seasonal and synchronous reproductive cycles, in which it is difficult to decouple the effects of internal and external factors that can affect parasite abundance in each sex. Species with asynchronous reproductive cycles provide the opportunity to study the effects of seasonality and reproductive condition separately, but few studies have documented variation in parasite abundance in these species. We made an extensive comparison of parasite load and inflammatory response of the lizard Sceloporus torquatus, a species with asynchronous reproductive cycles, throughout its active period. We hypothesized that the parasite load would be higher in the period of maximum gonadal activity for each sex, negatively related to body condition and inflammatory response. Our results partially support the hypothesis; males had more parasites in summer than in spring and autumn, while females had more parasites in spring and summer than in autumn; however, we do not find a relationship between parasite load, body condition and inflammatory response. Our results indicated that host-parasite interactions are complex and depend upon both environmental and internal factors. Therefore, longer-term studies may provide a more comprehensive picture of host-parasite dynamics in populations of wild lizards.
The dingo fence along the border of NSW and SA (A), Fledgling wedge-tailed eagles in a nest in NSW (B), Nest being surveyed for prey remains in South Australia (C) and red kangaroo with young at foot that died in the mass mortality event in 2018 (D)
Map of the study region showing the location of eagle nests and driving transects
Mean number of prey taxa found at eagle nests where dingoes were common and where dingoes were rare. Error bars represent 1 standard error
nMDS ordination comparing similarity of prey remains found at eagle nests on each side of the dingo fence. Presence/absence data, Bray–Curtis similarity matrix, stress = 0.07. Less than 36 symbols are presented because points overlap.
Abundance indices for eagle prey species A kangaroos, B rabbits and C bearded dragons between March 2015 and March 2019
Removal of apex predators can have far-reaching effects on the organization and structure of ecosystems. This occurs because apex predators can exert strong suppressive effects on their prey and competitors and perturbation of these interactions can shift the balance of interactions between dyads of species at lower trophic levels and trigger trophic cascades. Dingoes ( Canis dingo ) are Australia’s largest mammalian carnivore. Because they are a pest to livestock producers, dingo populations are suppressed in many regions. Suppression of dingo populations has been linked to a suite of ecosystem changes due to ensuing population irruptions of their prey and competitors. Here, we investigate the impact that the suppression of dingoes has on the diet of wedge-tailed eagles ( Aquila audax ) in Australia’s Strzelecki Desert. Wedge-tailed eagles are generalist predators that readily shift their diet in relation to prey availability. We assessed the abundance of species frequently preyed on by eagles and quantified prey remains at eagle nests located on either side of a dingo-proof fence where dingoes were common and rare, respectively. Wedge-tailed eagles consumed more species where dingoes were rare compared to where dingoes were common. Kangaroos (Macropodidae) and western bearded dragons ( Pogona vitticeps ) were more abundant and were consumed more frequently by eagles where dingoes were rare. Introduced European rabbits ( Oryctolagus cuniculus ) were the prey item most frequently identified at eagle nests. However, rabbits were more abundant and their remains were found at a higher proportion of nests where dingoes were common. Our results provide evidence that shifts in the composition of vertebrate assemblages associated with the presence/absence of dingoes, particularly the irruption of kangaroos, influence the diet of wedge-tailed eagles. More generally, by showing that the presence/absence of dingoes can influence the diet of wedge-tailed eagles, our study highlights how pervasive apex predators’ effects on ecosystems can be.
The article deals with the study of planktic foraminifera and biostratigraphic studyin the Shiranish Formation
Phenological overlap with pollinators is crucial for reproductive success in insect-pollinated plants. In this study, we examined whether pollinator visitation successfully occurred during an entire flowering season in two populations of the insect-pollinated spring ephemeral Trillium camschatcense in the Tokachi region of Hokkaido, northern Japan. We bagged flowers and excluded pollinator visitation during either the first or the last half of the entire flowering season to compare pollination success between the two periods. The two populations have experienced differing levels of climate warming in the last 60 years, which impacted pollinator visitation. In the population experiencing temperature rise more rapidly, fertilization rate and seed set decreased sharply when bagged during the first half period, indicating that pollinator visitation is skewed to the early part of the flowering season. The temporal skewness of pollination success would be an early warning signal of the impacts of climate warming on the reproductive success of T. camschatcense.
Conventional oligopeptide synthesis techniques involve environmentally harmful procedures and materials. In addition, the efficient accumulation of oligopeptides under Hadean Earth environments regarding the origin of life remains still unclear. In these processes, the formation of diketopiperazine is a big issue due to the strong inhibition for further elongation beyond dipeptides. Hydrothermal media enables environmentally friendly oligopeptide synthesis. However, hydrothermal oligopeptide synthesis produces large amounts of diketopiperazine (DKP), due to its thermodynamic stability. DKP inhibits dipeptide elongation and also constitutes an inhibitory pathway in conventional oligopeptide synthesis. Here, we show an efficient pathway for oligopeptide formation using a specially designed experimental setup to run both thermal and non-thermal discharge plasma, generated by nano-pulsed electric discharge with 16-23 kV voltage and 300-430 A current within ca. 500 ns. DKP (14%) was converted to dipeptides and higher oligopeptides in an aqueous solution containing alanine-DKP at pH 4.5, after 20 min of 50 pps thermal plasma irradiation. This is the first study to report efficient oligopeptide synthesis in aqueous medium using nano-pulsed plasma (with thermal plasma being more efficient than non-thermal plasma) via DKP ring-opening. This unexpected finding is implicative to evaluate the pathway how the oligopeptides could have accumulated in the primitive Earth with high-energy plasma sources such as thunder as well as to facilitate the green synthesis of oligopeptides.
A Nonanal amount from Sapium sebiferum flowers at five time points on a sunny day. Each bar means mean ± SE of nonanal from samples of 12 cluster of flowers. Each group had three biological replicates. Data were normalized by square-root transformation and were analyzed by ANOVA test followed by Fisher’s PLSD test. “*” represents significant difference (p < 0.05). B Nonanal amounts from buds, blooming, and faded flowers of Ligustrum compactum. Each bar shows mean ± SE of nonanal amount from samples of 250 flowers, and each group had three biological replicates. Data were normalized by square-root transformation and were analyzed by ANOVA test followed by Fisher’s PLSD test. “*” represents significant difference (p < 0.05), and no “*” represents no significant difference
A Nectar drop on Sapium sebiferum nectaries viewed under microscope. Flowers were magnified 40 times. B A nectar drop in a Ligustrum compactum flower under microscope. Flowers were magnified 40 times also. C Number of flowers or nectaries of Sapium sebiferum and Ligustrum compactum with nectar drops from samples of 30 nectaries studied. Each group in Sapium sebiferum and Ligustrum compactum flowers had 30 and 6 replicates respectively.D Nonanal amounts from netted and control flowers. Twelve cluster of Sapium sebiferum flowers and 250 Ligustrum compactum flowers of the netted and control groups were sampled and analyzed by needle trap and GC–MS. Each group had three biological replicates. Each bar shows the mean ± SE. Data were analyzed using one-way ANOVA test. “*” represents significant difference (p < 0.05) between two groups
Nectar and nonanal amounts from Castanea henryi flowers. The left bars were nectar amounts from 5 clusters of flowers and the right bars were nonanal amounts from the relative nectar droplets. Each bar shows the mean ± SE. Data were analyzed using one-way ANOVA test. “*” represents significant difference (p < 0.05) between two groups
EAG response of honeybees to 5 floral components. Antenna response to the 2 mL/L concentration of each of the five compounds. Each bar shows the mean ± SE of EAG response. Data were analyzed using ANOVA tests followed with Fisher’s PLSD test. Different letters represent significant difference (p < 0.05), and same letters represent no significant difference
The attractiveness of 5 floral odors to honeybees using mimic flowers. Each bar shows the number of foragers that landed on each of the five odors in the preference test expressed as a percentage of the 193 foragers tested in this study. Choice data were compared to the nonanal group with a chi-square test. “*” represents significant difference (p < 0.05) between nonanal and other four groups
Volatile odors from flowers play an important role in plant-pollinator interaction. The honeybee is an important generalist pollinator of many plants. Here, we explored whether any components of the odors of a range of honeybee-pollinated plants are commonly involved in the interaction between plants and honeybees. We used a needle trap system to collect floral odors, and GC–MS analysis revealed nonanal was the only component scent detected in 12 different honeybee-pollinated flowers and not present in anemophilous plant species. For Ligustrum compactum, blooming flowers released significantly more nonanal than buds and faded flowers. For Sapium sebiferum, nonanal release through the day correlated with nectar secretion. Experimentally increasing nectar load in flowers of Sapium sebiferum, Ligustrum compactum, and Castanea henryi increased nonanal levels also. Nonanal was also detected in flower nectar and honeys from experimental colonies. Electroantennogram recordings and behavioral observations showed that untrained honeybees could detect and were strongly attracted to nonanal. We argue that nonanal persists in both honey and nectar odors facilitating a learned association between nonanal and food reward in honeybees.
Polistes is one of the most widely distributed and extensively studied primitively eusocial wasps. Based on where they are found, there are two established nesting cycles in this genus. The temperate wasps follow an annual cycle with diapause in winter while the tropical wasps of South America can initiate nests any time of the year and do not hibernate. Additionally, some subtropical Polistes are known to form nest free aggregations during the cold, dry, unfavorable season. Although several species of Polistes wasps are found in India, our knowledge about their biology is pitifully small and is restricted to taxonomic reports. Here, we report the unique nesting cycle of Polistes wattii, a wasp abundantly found in north India and other Asian countries. P. wattii hibernates in winter as well as forms nest-free aggregations in the dry summer season and thus has a nesting cycle with two inactive periods, which no other Polistes is known to follow. The study site in North India experiences short, cold, snow-free winters, spring, a very dry early summer, and humid late summer with intermittent rain. We found that P. wattii here shows several unique adaptations to survive the long Indian summer where it shows two rounds of nest-founding in the same year, once as overwintered, solitary foundress in spring and once with multiple foundresses during summer. To meet the demands of expanding colony in late summer, P. wattii often adds multiple combs to their nest, which are architecturally different from the multiple comb nests reported from neotropical regions and strikingly different from all temperate Polistes who make only single comb nests. This study investigates the nesting biology and natural history of P. wattii to understand how they maximize survival and fitness.
A male adult L. luae in its natural habitat (a) and an example of a male calling song (b) and its spectrogram (c). PCA summarising the calling behaviours and call parameters across 11 individuals of L. luae (d). For the PCA, the Cricket ID refers to the identity of each of the 11 individuals; the arrows indicate how the different traits correlate with one another
Significant effects of fresh weight and age group on the number of calls produced (a), and significant effects of fresh weight, age group and temperature on time taken to start calling (b). The lines represent predictions based on the final GLMM (a) and LMM (b) after stepwise simplification. The final models only contain the significant explanatory variable(s) as shown in the plots. The effects of fresh weight as a continuous explanatory variable (b) were represented using three lines (0.24 g, 0.27 g, 0.29 g). The data points in circles of different sizes correspond to the individual crickets with different fresh weights in b; otherwise, data points are represented using ‘ + ’ in (a). The data points in green and blue correspond to the ‘young’ and ‘old’ age groups of the cricket
Significant effects of fresh weight on call duration (a); significant effects of fresh weight and temperature on the amount of sound produced per call (b); significant effects of age group, fresh weight, and temperature on trill duration (c); significant effects of age group, fresh weight, and temperature on dominant frequency (d). The lines represent predictions based on the final LMMs after stepwise simplification. The final models only contain significant explanatory variable(s), as shown in the plots. The effects of fresh weight as a continuous explanatory variable (b, d) were represented using three lines (0.24 g, 0.28 g, 0.31 g). The data points in circles of different sizes correspond to the individual crickets with different fresh weights in b–d; otherwise, data points are represented using ‘ + ’ in (a). The data points in green and blue correspond to the ‘young’ and ‘old’ age groups of the cricket in c, d; otherwise, data points are represented in black
Significant effects of temperature and/or age group on trill syllable duration (a) and period (b). The lines represent predictions based on the final LMMs after stepwise simplification. The final models only contain significant explanatory variable(s), as shown in the plots. The data points in green and blue correspond to the ‘young’ and ‘old’ age groups of the cricket in b; otherwise, data points are represented in black in a
Driven by natural and sexual selection, calling behaviours and call parameters can vary within and between individuals. Phenotypic plasticity can be influenced by environmental conditions (e.g., temperature), size, body condition, and age. Crickets have been classic model organisms for studying the evolution of acoustic communication, but previous studies have focused on field crickets, for which males call at a low frequency, while females exhibit phonotaxis. This study holistically investigated the plasticity of calling behaviours and call parameters across a temperature gradient in a species of lebinthine crickets and examined plasticity between and within individuals. These crickets exhibit a unique communication system, including males calling at a near-ultrasonic frequency while actively searching for females. Ten recording assays at different temperatures were done on males of different sizes and body conditions, half of the assays when the males first became adults and another half 1 month later. Size, body condition, and age group of male crickets, as well as the ambient temperature, had different effects on different calling behaviours (e.g., number of songs produced) and call parameters (e.g., call duration, trill syllable period), even when the acoustic traits were correlated. The crickets also exhibited acclimatisation to the experimental conditions in their calling behaviours and acoustic traits to repeated assays. We also found that calling behaviours were less repeatable than temporal call parameters (e.g., call duration, trill duration), which in turn, were less repeatable than the spectral call parameter (dominant frequency).
Extranuptial nectaries (ENNs) in Pitcairnia burchellii inflorescences. a. Young inflorescence showing floral buds (fb) totally or partially covered by subtending bracts (br). Insert shows a nectar droplet on the abaxial surface of a young bract. b, c. Inflorescences bearing expanded floral buds with bracts (br) restricted to pedicels; notice that the corolla (co) expands outward the calyx (ca). Note numerous ants foraging on an inflorescence in B and feeding from the sepals of a floral bud (insert). d. Mature flower at anthesis showing the long tubular corolla. Note ants (arrowhead) foraging on the sepals of the flower. e. Ants directly feeding from the subtending bracts of young floral buds. f–h. Nectar droplets (arrows) appearing on the adaxial surface of sepals (f, h) and bracts (g) after the ant-exclusion procedure. (br, bract; ca, calyx; co, corolla; fb, floral bud; pd, peduncle; se, sepal)
Structural aspects of Pitcairnia burchellii bracts and sepals. a, b. Cross-sections of a non-secreting portion (a) and a secreting (b) portion of sepals. c. Cross-section of a secreting portion in a bract (b). Note the uniseriate epidermis (ep) with protruded stomata (arrows) and trichomes (tr) on the abaxial surface. The insert in ‘a’ shows the general structure of a vascular bundle (vb). d. Detail of the cuticle (in red) covering the adaxial surface of a sepal. Note the cell-wall ridges typical of this surface of the epidermis. e. Detail of epidermal cells on the abaxial surface of a sepal, showing conspicuous thickening of the outer periclinal walls (arrowhead). f, g. Stomata in cross-sections of a secreting portion (f) and a non-secreting portion (g) of sepals. Note the protruded guard cells delimiting a substomatal chamber. h. Abaxial surface of a sepal showing numerous stomata (arrows) and trichomes (tr). i-j. Detail of stomata in a secreting (i) and non-secreting (j) portions of a sepal. Note accumulated material (asterisk) in the stomata in ‘i’. (ch, chlorenchyma; cr, crystal idioblast; ep, epidermis; ph, phloem; sc, substomatal cavity; tr, trichome; vb, vascular bundle; wp, water-storage parenchyma; xy, xylem)
Phylogenetic representation of the distribution and topology of ENNs in Bromeliaceae. On the left, maximum-likelihood/Bayesian inference tree, modified from Givnish et al. (2011). ENNs occur within the subfamilies Bromelioideae (Clade A), Pitcairnioideae (Clade B) and Tillandsioideae (Clade E). In the Pitcairnioideae, ENNs were indicated to occur specifically within the “xeric clade” (Clade C) and Pitcairnia (Clade D). On the right, schematic depictions of inflorescence organs (sepals/bracts) showing the general position of ENNs (dark spots). Question marks indicate uncertain information. See Table 1 for data references
Nectar plays important roles in the relationship between plants and other organisms, both within pollination systems and as a defense mechanism. In the latter case, extranuptial nectaries (ENNs) usually attract patrolling arthropods that reduce herbivory. ENNs have been frequently reported within the “xeric clade” of Bromeliaceae, but their occurrence in other groups of bromeliads is largely unexplored, especially considering their position, secretory activity and structure. After observing the presence of ants constantly patrolling the inflorescences of Pitcairnia burchellii Mez, we searched for the presence, secretory activity, and structure of ENNs in this species. We also provide a brief review of the occurrence ENNs in Bromeliaceae. The distribution of nectaries was assessed using ant-exclusion experiments, while structural analysis was performed using standard methods for light and scanning electron microscopy. The presence of sugars in the secretion was assessed by thin-layer chromatography and glucose strip tests. Nectaries in P. burchelli are non-structured glands on the adaxial surface of floral bracts and sepals. Bracts and sepals are distinct spatial units that act over time in the same strategy of floral bud protection. Literature data reveals that ENNs might be more common within Bromeliaceae than previously considered, comprising a homoplastic feature in the family. Future perspectives and evolutionary and taxonomic implications are discussed.
A map of the sampling area (dark gray: Environmental Protected Area of Morro da Pedreira – Minas Gerais – Brazil). Light gray: Brazil, dark green: Minas Gerais state
Schematic image of the host tree, Vochysia thyrsoidea (A), and the mistletoe Psittacanthus robustus (B) in campo rupestre. We are displaying a mirrored photography to increase clarity of the studied system
Structural equation models showing the best-supported models (according to Table 2) of the effect of the parasitic plant on A species richness (Fisher’s C = 8.68, P = 0.563, AICc = 44.24) and B abundance of leaf-chewing insects (Fisher’s C = 8.68, P = 0.563, AICc = 44.24), sap-sucking insects, ants and on the percentage of herbivory in the host plant. Solid red arrows represent significant negative paths (P ≤ 0.05 piecewise SEM), and solid black arrows represent significant positive paths (P ≤ 0.05 piecewise SEM). Arrows for non-significant paths (P ≥ 0.05) are in light gray. The thickness of the significant paths represents the magnitude of the standardized regression coefficient or effect sizes, given on the arrows. Conditional R²s for component models are given under the circles of endogenous variables. ***P ≤ 0.001; **P ≤ 0.01; *P ≤ 0.05
Parasitic plants are important sources of stress and can strongly impact their host plants through direct and indirect associations with other herbivores and their associated organisms. In the tropics, mistletoes are frequent parasitic plants, influencing different trophic levels involved with the host plant. Here, we investigated the direct and indirect influences of multiple partners involved in interactions between the mistletoe Psittachantus robustus and its host tree, Vochysia thyrsoidea. More specifically, we assessed if the presence of the mistletoe modified herbivory levels of its host by altering the diversity of associated insects. We found that insect feeding guild modulated mistletoe influence on insect community, and there were fewer species and individuals of leaf-chewing insects in parasitized than non-parasitized trees. Despite this decrease in leaf-chewing insects, there were increased levels of herbivory in parasitized plants. Mistletoes’ presence did not influence the hemipteran sap-sucking insects, but this herbivore guild directly responded to the abundance of their associated ants. Overall, our study found empirical support for the crucial role of mistletoes on their host-associated organisms, ultimately shaping the herbivory levels of their tree hosts. By exposing the distinct effects of the different partners involved, our results shed light on the intricated interactions mediated by parasitic plants, opening the path for new investigations.
Setup with foraging arena (left) connected by a bridge to a subcolony of 3 fungus chambers and a final waste box (brown). Diluted honey (yellow dish) and water (blue dish) were offered in the small box before the nest entrance (black arrow). The yellow arrow marks the chamber that experienced leaf deprivation in the ‘undernourished’ experiment
a Number of leaf discs delivered to different chambers in both the nourished and undernourished experiments (box: 25–75% percentiles, line: median, whiskers: min–max values; 2-way repeated-measures ANOVA and Kruskal–Wallis test with Tukey post hoc test; boxes sharing the same letters do not differ statistically, P ≤ 0.05). Figure legend applies to both a and b. b First delivery of offered discs in each chamber, as percentage of the total delivery of first discs for each condition (nnourished = 36, nundernourished day 1 = 39, nundernourished day 2 = 39; Fisher’s exact test, **P < 0.01, *P ≤ 0.05, ns = not significant)
Statistics for the first delivery of offered leaf discs, after Fisher's exact test: a Pairwise comparisons of the overall distribution pattern between different experimental conditions. For each chamber, counts of delivered discs were pooled for the three time points, as there were no statistical differences in the delivery among them; b Pairwise comparisons between different experimental conditions, for each chamber
Leaf-cutting ants are highly successful herbivores in the Neotropics. They forage large amounts of fresh plant material to nourish a symbiotic fungus that sustains the colony. It is unknown how workers organize the intra-nest distribution of resources, and whether they respond to increasing demands in some fungus gardens by adjusting the amount of delivered resources accordingly. In laboratory experiments, we analyzed the spatial distribution of collected leaf fragments among nest chambers in Acromyrmex ambiguus leaf-cutting ants, and how it changed when one of the fungus gardens experienced undernourishment. Plant fragments were evenly distributed among nest chambers when the fungal symbiont was well nourished. That pattern changed when one of the fungus gardens was undernourished and had a higher leaf demand, resulting in more leaf discs delivered to the undernourished fungus garden over at least 2 days after deprivation. Some ants bypassed nourished gardens to directly deliver their resource to the chamber with higher nutritional demand. We hypothesize that cues arising from that chamber might be used for orientation and/or that informed individuals, presumably stemming from the undernourished chamber, may preferentially orient to them.
A Bayesian phylogenetic tree of partial mitochondrial CO1 sequences constructed using GTR + g + i model in MrBayes for different Polistes species. P. wattii and P. indicus sequences generated
Polistes is one of the most widely distributed and extensively studied primitively eusocial wasps. Based on where they are found, there are two established nesting cycles in this genus. The temperate wasps follow an annual cycle with diapause in winter while the tropical wasps of South America can initiate nests any time of the year and do not hibernate. Additionally, some subtropical Polistes are known to form nest free aggregations during the cold, dry, unfavorable season. Although several species of Polistes wasps are found in India, our knowledge about their biology is pitifully small and is restricted to taxonomic reports. Here, we report the unique nesting cycle of Polistes wattii, a wasp abundantly found in north India and other Asian countries. P. wattii hibernates in winter as well as forms nest-free aggregations in the dry summer season and thus has a nesting cycle with two inactive periods, which no other Polistes is known to follow. The study site in North India experiences short, cold, snow-free winters, spring, a very dry early summer, and humid late summer with intermittent rain. We found that P. wattii here shows several unique adaptations to survive the long Indian summer where it shows two rounds of nest-founding in the same year, once as overwintered, solitary foundress in spring and once with multiple foundresses during summer. To meet the demands of expanding colony in late summer, P. wattii often adds multiple combs to their nest, which are architecturally different from the multiple comb nests reported from neotropical regions and strikingly different from all temperate Polistes who make only single comb nests. This study investigates the nesting biology and natural history of P. wattii to understand how they maximize survival and fitness.
Meliponine bees use chemical-based nestmate discrimination to protect their colonies from unrelated intruders. However, species from the Amazon basin are relatively poorly known from this perspective. Here, we investigated Melipona paraensis nestmate discrimination in different contexts (nests vs. neutral arenas), testing aggression in bees facing other bees varying in age and origin (same/different colony or a different kleptoparasitic meliponine species) or experimentally treated with odors from unrelated colonies. As expected, M. paraensis did not discriminate against callow non-nestmate workers with weak/undifferentiated chemical signatures. Workers specialized in nest defense aggressed intruders more often than non-specialized workers, but were less aggressive in neutral arenas than in the nest. Our study provides novel behavioral information relevant for social insect research and meliponiculture.
This paper presents an experimental study on surface icing on leaves in six plant species having different surface micromorphology and wettability properties. Contrary to previous studies on ice crystallization, which have been mainly performed by using infrared video thermography, we applied a Cryo-SEM approach allowing not only characterization of plant surfaces in their native conditions but also visualization of ice crystal formation on the native plant surfaces at the micro- and nanoscales. The Cryo-SEM was also used as an experimental device to freeze water vapor, thaw ice crystals, and freeze fluid water on the plant surface again. The experiments clearly demonstrate that trichome coverage (especially with several distinct layers) and 3D wax projections can be recognized as anti-icing strategies of plants. Trichomes can prevent and delay ice formation by being nucleation points for the formation of ice from vapor and protect the plant surface from overcooling, when fluid water freezes in contact with the leaf surface. The study shows for the first time two important effects that might reduce plant cell freezing rate: the presence of air pockets between wax projections that protect from direct contact between ice crystals and the plant cuticle and elimination of fluid water after thawing and preventing further re-freezing on the surface. The detailed knowledge obtained here is not only important for plant ecology, evolution, and plant protection but also for looking for potential biomimetic strategies that reduce/avoid icing of cultural plants and artificial technical surfaces. Graphical Abstract
Melanism is a polymorphic phenotype caused by the number and density of melanocyte cells producing melanin pigment in the skin and widely observed in snakes. The frequency of this coloration in populations is associated with its opposing fitness consequences and can be closely related to species-specific characteristics such as sex, reproduction, and nutrition, as well as environmental factors such as climate and geography. Although melanism is frequently seen in snakes, the skin structure of melanistic individuals has not been studied in detail. Also, the impact of the black phenotype on habitat use has not yet been clarified in this species. Here, we show a comparison of typical and melanistic morphs of the grass snake Natrix natrix population of Anatolia for the first time in terms of skin structure, habitat, and sex. We found that melanistic individuals, in which partial melanism is more abundant than total melanism, comprise 13% of the population. Melanocyte area of the skin is 1.4 times greater in melanistic compared to the typical individuals. The epidermis is thicker in typical morphs by 7.7%. Hinge regions between adjacent scales do not bare melanocytes in both morphs. As for habitat utilization, we revealed that melanistic individuals of the Işıklı population tend to occur closer to water bodies than typical ones. Our data provide a new perspective on poorly known aspects of color polymorphism and habitat use of widely distributed, semi-aquatic Natrix natrix.
Triple T-maze. Distances between T-junctions and those between T-junction and exit are both 4 cm. S, start point; A–H, exit
Linearity of woodlice. A Effect of access to the opposite sex on linearity (experiment 1). B Effect of the loads on linearity (experiment 2). Different letters on each bar show significant difference at the 5% level obtained using the generalized linear mixed model (GLMM). The significance level was corrected after the Tukey’s test
Relationship between the linearity rate on each tested date and the days from the initiation of the running trials (October 25, 2017). Because we manipulated the rearing conditions of females after the first maze test, we calculated the regression line using the data after the second test for females
Turn alternation (TA) is the tendency to turn in the opposite direction of an immediately preceding turn when moving forward, resulting in an overall linear trajectory. TA has been observed in many animals, and terrestrial isopods are considered model organisms for studying TA. Optimizing their fleeing speed and trajectory helps isopods efficiently escape from predatory threats. However, since reproduction induces morphological and physiological changes, individuals might adjust their trajectories depending on their altered mobility. In this study, we investigated the effect of reproduction-related factors on the frequency of TA, which enables linearity, in the common rough woodlouse Porcellio scaber. The results showed that breeding females enhanced their linearity more than nonbreeding females and males. Furthermore, females without access to a potential mate enhanced their linearity more than females and males with access to a potential mate and maintained a high linearity for approximately 40 days. In terrestrial isopods, continuous TA for linearity may be used to avoid reproductive failure because of lack of encounters with the potential mate or to compensate for low running ability due to physical or physiological loads. Conversely, individuals that do not need to worry about reproductive failures or individuals with small loads could perform the random turn that does not require learning or memory. This is the first study to show that the events involved in reproduction affect the linearity shown by continuous TA in terrestrial isopods.
a Locations of Fenhsiang Formation sections in the Ordovician of South China. b Outline of lithostratigraphy of the Pengshui section showing the distribution of bryozoans in the Fenhsiang Formation. Fm., formation; HHY, Honghuayuan
Stratigraphical ranges of the major bryozoan groups that occur in the Fenhsiang Formation (Tremadocian) of South China and elsewhere in early and middle Ordovician. Black circles indicate previously known earliest occurrences from Baltics; solid grey circles indicate previously known earliest occurrences from North America; triangles indicate previously known earliest occurrences from Novaga Zemlya, Russia; stars indicate new occurrences reported here from South China. Based on the data of Ernst et al. (2014), Koromyslova (2011), Fedorov et al. (2017), Koromyslova and Fedorov (2021), and the current study
Thin sections showing examples of the diverse bryozoans from the Fenhsiang Formation (Tremadocian) of South China. a Esthoniopore Dianulites sp. NIGP 177,964. b Fistuliporine cystoporate Profistulipora sp. NIGP 177,965. c Ceramoporine Ceramopora sp. NIGP 177,966. d Ceramoporine cystoporate Haplotrypa sp. NIGP 177,967. e Ceramoporine Amsassipora sp. NIGP 177,968. f Amplexoporine trepostome Orbignyella sp. NIGP 177,969. g Ptilodictyine cryptostome Prophyllodictya sp. NIGP 177,970. h Rhabdomesine Vercoclema sp. NIGP 177,971. i Ptilodictyine Trepocryptopora sp. NIGP 177,972. j Trepostome Goldfussitrypa sp. NIGP 177,973. k Arthrostylid rhabdomesine Nematopora ovalis. NIGP 177,974. K Scales: a, f–h, j, 500 µm; b–e, 200 µm; i, k, 100 µm. NIGP (= NIGPAS), Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
Thin sections showing vesicles (a–c), mesozooecia (d), and exilazooecia (e) in bryozoans from the Fenhsiang Formation. aProfistulipora sp. NIGP 177,975. bHennigopora sp. NIGP 177,976. cFistulipora sp. NIGP 177,977. d Undetermined halloporine trepostome NIGP 177,978. eOrbignyella sp. NIGP 177,979. Scale bars: a, 200 µm; b, c, e, 100 µm; d, 500 µm
Range-through bryozoan generic diversity in the Ordovician, with the new data from this study added to that of Ernst (2018). Hirn, Hirnantian
Although phosphatized bryozoans have been described recently from the early Cambrian, the first unequivocal bryozoan fossils with hard skeletons are known from the Ordovician. Recent discoveries of bryozoans in the early Ordovician (Tremadocian) of South China have greatly expanded our understanding of the diversification of these colonial lophophorates. In particular, the Fenhsiang Formation of Late Tremadocian age (Migneintian) in Hubei Province is proving to be particularly rich in bryozoans. Here we record 24 species, including several yet to be formally described, belonging to 18 genera and four palaeostomate suborders (Esthonioporata, Cystoporata, Trepostomata, and Cryptostomata). Bryozoan diversity in the Fenhsiang Formation matches levels more typical of younger faunas of Middle Ordovician age. The presence of diverse and morphologically disparate taxa close to the base of the Ordovician suggests rapid diversification following the first appearance of bryozoans with calcified skeletons, and/or the existence of as yet unknown biomineralized bryozoans in the Cambrian.
Panel A shows the location of the Stelvio National Park. Panel B shows the sampling area, within the Trentino sector in the south-eastern part of the Stelvio National Park. Panel C shows the location (northern and southern exposure) of the samples deployed to experimentally investigate the temporal stability of fecal cortisol metabolite levels in chamois and red deer. Red dots represent chamois samples, blue dots represent red deer samples; dots are not representative of true number of samples, but only of their approximate location. The asterisk (*) represents the relative location of the temperature-recording devices
Marginal effects of the model selected to explain the variation in fecal cortisol metabolite levels over time in chamois (left) and red deer (right). Raw data are reported in both panels
Random effects of the model selected to explain variation in fecal cortisol metabolite levels over time in chamois (left) and red deer (right)
Fecal cortisol metabolites (FCMs) are widely used to track stress responses in wildlife and captive species. Rules of thumb suggest that samples should be collected as soon as possible after defecation, to avoid decay of FCMs. To date, however, only a few studies investigated the stability of defecated FCMs over time, and most of them were conducted in controlled laboratory conditions. Here, we investigated the stability of FCMs over seven consecutive days, in two mountain-dwelling ungulates, under natural environmental conditions using a semi-experimental approach. Fecal samples from Northern chamois Rupicapra rupicapra (n = 24) and red deer Cervus elaphus (n = 22) were collected in summer of 2020 within the Stelvio National Park, Italy, and placed in an open area above 2000 m a.s.l. For the next 7 days, we collected a portion of each sample, and all sub-samples were analyzed with an 11-oxoetiocholanolone enzyme immunoassay. Exposure, temperature, and precipitation were fitted as covariates in non-linear generalized mixed models to assess FCM variation over time, and competing models were selected using AICc. For chamois, the best model included only time as a predictor, while for red deer, it included time, precipitation, and exposure. For both species, FCM values decreased rapidly from the first days after deposition until the fourth day. For red deer, in northern-exposed samples, FCM values decreased slower than in south-exposed ones; furthermore, FCM values increased with increasing precipitation. Our results offer a solid methodological basis to wildlife researchers and practitioners interested in the investigation of the ecological factors affecting stress variation in wildlife and support the recommendation to collect samples as fresh as possible, to avoid misleading inference. Further studies are necessary to evaluate the stability of FCMs when other enzyme immunoassays are used.
Pygidial glands of a female of C. (C.) intricatus: a anatomical position of the glands presented with yellow silhouettes; b appearance of the glands in dissected abdomen. Abbreviations: co, colon; pg, pygidial gland apparatus; rc, rectum; rep, reproductive system; t, tracheole. Scales = 10 mm (a) and 2 mm (b). Photo N. Vesović
The fractional inhibitory concentration index (FICI) values of methacrylic and angelic acids against selected bacterial strains
Pygidial gland morphology of C. (C.) intricatus: a whole pygidial gland apparatus; b cluster of secretory lobes; c main collecting canal; d connection of a main collecting canal with a reservoir; e transition of the narrow part of a reservoir into an efferent duct; f posterior part of an efferent duct; g cross section of a muscle-coated reservoir (position of cross section of the reservoir is shown in an orange-bordered circular inset). Abbreviations: ag, accessory gland; bm, basal membrane; ed, efferent duct; ep, epidermis; epc, epicuticular spikes; lmcc, lumen of main collecting canal; lr, lumen of reservoir; lsm, longitudinal section of muscle fibers; mcc, main collecting canal; mf, muscle fibers; om, opening muscle; ov, opening valve; r, reservoir; rcc, radial collecting canal; sl, secretory lobes; t, tracheole; tsm, transverse section of muscle fibers. Scales = 1.0 mm (a), 0.5 mm (e), and 0.2 mm (b–d, f and g). Photo N. Vesović
Pygidial gland secretions are used as repellent defensive allomones in ground beetles. We provide the first precise data on the chemical composition and antimicrobial potency of the secretion of the blue ground beetle, as well as on the morphology of its pygidial glands. The latter structures were not previously studied chemoecologically and morphologically, and we hypothesized that their secretion may have some antimicrobial action, as is the case with certain Carabus species. Gas chromatography-mass spectrometry (GC-MS) was used to identify methacrylic and angelic acids as dominant chemicals in the secretion from individuals of three populations of the blue ground beetle in Serbia. We tested its secretion against selected strains of medically important microorganisms. The secretion exibits antimicrobial action against certain bacterial species and all tested micromycetes. The most significant antifungal effect of the secretion was against Penicillium ochrochloron, which is more sensitive to the secretion than to commercial antifungal drugs ketoconazole and bifonazole. Bifonazole achieved minimum inhibitory concentrations against Trichoderma viride at more than three times higher value than did the secretion, indicating a significant antifungal effect of the secretion against this micromycete as well. Additionally, we tested commercially available standards of two dominant chemicals in the secretion to investigate their interaction and antimicrobial role in the secretion. Finally, we describe all glandular morpho-functional units of the blue ground beetle. Our results suggest that the secretion of the blue ground beetle may serve not only defensive but also antimicrobial functions, which likely aid the survival of this beetle in the microbial-rich forest litter habitat. Graphical abstract
Red propolis is a substance produced by bees by mixing resins from plants with wax, oils, and other secretions to protect the hive against natural enemies. Dalbergia ecastaphyllum (L.) Taub. (Fabaceae) is the primary botanical source of the Brazilian red propolis, where bees Apis mellifera L. collect a reddish resin from the stems to produce propolis. This species occurs in coastal dune and mangrove ecosystems, where local beekeepers install their beehives for propolis production. The induction of propolis production was virtually unknown. Previous reports and field evidence suggested that the reddish resin available in D. ecastaphyllum stems was not produced spontaneously but induced by the presence of a parasitic insect that feeds on the plant's stems. Research in the apiaries of the beekeepers' association of Canavieiras, Bahia, Brazil, led to the capture of a jewel beetle of an unknown species of the genus Agrilus Curtis (Buprestidae). It was confirmed that this jewel beetle is a red propolis production inductor. The adult and immature of this new species, Agrilus propolis Migliore, Curletti, and Casari sp. nov. are here described and illustrated. Behavioral information on the biology and chemical ecology confirms that the reddish resin of D. ecastaphyllum is directly related to the beetle attack and only occurs when Agrilus propolis sp. nov. adults emerge from the plant stem. This information is very important for Brazilian propolis producers interested in expanding red propolis production, which can have favorable effects on the economy of mangrove communities, promoting income generation, creating new business opportunities, and helping to sustain local communities and families.
Schematic of the method of application of pesticides on plants, pests, and beneficial organisms in agriculture
Comparison between temperature variation (A) and pesticide consumption (B) worldwide (
Source: FAO 2020)
Climate change mediated by anthropogenic activity induces significant alterations on pest abundance and behavior and a potential increase in the use of agrochemicals for crop protection. Pesticides have been a tool in the control of pests, diseases, and weeds of agricultural systems. However, little attention has been given to their toxic effects on beneficial insect communities that contribute to the maintenance and sustainability of agroecosystems. In addition to pesticide-induced direct mortality, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. This review describes the sublethal effects of pesticides on agriculturally beneficial insects and provides new information about the impacts on the behavior and physiology of these insects. The different types of sublethal effects of pesticides used in agriculture on pollinators, predators, parasitoids, and coprophagous insects were detailed.
Animals can produce different phenotypes from the same genome during development, environmental adaptation and evolution, which is mediated by epigenetic mechanisms including DNA methylation. The obligatory parthenogenetic marbled crayfish, Procambarus virginalis, whose genome and methylome are fully established, proved very suitable to study this issue in detail. Comparison between developmental stages and DNA methylation revealed low expression of Dnmt methylation and Tet demethylation enzymes from the spawned oocyte to the 256 cell embryo and considerably increased expression thereafter. The global 5-methylcytosine level was 2.78% at mid-embryonic development and decreased slightly to 2.41% in 2-year-old adults. Genetically identical clutch-mates raised in the same uniform laboratory setting showed broad variation in morphological, behavioural and life history traits and differences in DNA methylation. The invasion of diverse habitats in tropical to cold-temperate biomes in the last 20 years by the marbled crayfish was associated with the expression of significantly different phenotypic traits and DNA methylation patterns, despite extremely low genetic variation on the whole genome scale, suggesting the establishment of epigenetic ecotypes. The evolution of marbled crayfish from its parent species Procambarus fallax by autotriploidy a few decades ago was accompanied by a significant increase in body size, fertility and life span, a 20% reduction of global DNA methylation and alteration of methylation in hundreds of genes, suggesting that epigenetic mechanisms were involved in speciation and fitness enhancement. The combined analysis of phenotypic traits and DNA methylation across multiple biological contexts in the laboratory and field in marbled crayfish may serve as a blueprint for uncovering the role of epigenetic mechanisms in shaping of phenotypes in macro-invertebrates.
The total ion chromatogram is shown for an extract of S. geminata workers (Gainesville, FL) immersed in hexane for 24 h. The seven peaks were demonstrated to be composed of single components rather than mixtures of co-eluting compounds (MassWorks, Cerno Bioscience, https:// cerno biosc ience. com). The structures for six of the seven alkaloids were determined by mass spectral fragmentation patterns, synthesis, and co-injection and are inserted into the chromatogram
South American fire ants, Solenopsis richteri and Solenopsis invicta , were accidently introduced into the southern USA in the 1900s and 1930s, respectively. The rapid spread and high population densities of S. invicta , and its potent sting, resulted in broad economic impacts and a variety of research efforts. In the 1970s, their venom alkaloids were identified as a complex blend of trans -2-methyl-6-alkyl- and alkenyl-piperidines. Solenopsis geminata is a worldwide tramp species but a native of the southern coastal regions of the USA. It was found to only produce cis - and trans -2-methyl-6-undecyl-piperidines. These alkaloids were considered the Solenopsis ancestral alkaloid profile since they were identified from female sexuals (potential queens) of all Solenopsis species in South and North America. The dramatic modification of alkaloids in Solenopsis invicta was attributed to their response to evolutionary pressure and the lack of change in S. geminata alkaloids due to no response to evolutionary pressure. Here we report the unexpected discovery of 6-undecyl-pyridine, 2-methyl-6-undecyl-pyridine and 2-methyl-6-(1)-undecenyl-pyridine as components of S. geminata worker venom, suggesting that S. geminata like its South American relatives have responded to evolutionary pressures. Our results will stimulate future research on S. geminata populations throughout the tropical/subtropical world.
In many animals, males engage in agonistic interactions. Color signals are commonly used to mitigate these potentially harmful interactions. Both pigment-based color and structural color, notably ultraviolet coloration, are used in this context to convey information, including an animal’s resource holding potential (RHP) or social status. Despite extensive previous work on this topic, the ability to change color in this context has received relatively little attention. Moreover, no studies have considered the visible and the ultraviolet components of this ability. Thus, whether changes in ultraviolet play a role in settling intraspecific disputes remains unknown. Here, we investigate the role of color change during intrasexual agonistic interactions in male panther chameleons (Furcifer pardalis). To do so, we combined behavioral experiments and color analysis. Our results show that the outcome of male intrasexual agonistic interactions depends on particular aspects of color change in the visible spectrum. Dominant males exhibit more brightness changes and Euclidian distance changes within the HSV color space at the level of the bands and interbands, suggesting a prominent role of these patterns in panther chameleon communication. Our results also align with previous studies in another chameleon species, thus supporting the key role of brightness changes in chameleon communication, at least in a competitive context. Interestingly, although our species did exhibit UV coloration, neither this coloration nor its changes seem to be involved in intrasexual agonistic interactions among males, possibly because those signals may be used for other purposes like attracting mates, repelling predators, or deception.
Hypothetical causal relationships between light and noise pollution (pollutants, gray square) and major pollination components (orange square): flower visits, pollen deposition, pollen germination, as well as fruit and seed set in Ceiba pentandra in an urban ecosystem in Merida, Yucatan, Mexico. The effects of floral resources (resources, blue square) at the tree level (floral display) and in the immediate surroundings (green cover) were also evaluated. The direction (positive or negative) of the symbols next to the arrows indicates the direction of the effect predicted
Artibeus bat visiting the flowers of Ceiba pentandra in an urban ecosystem in Merida, Yucatan, Mexico. Note that a large proportion if its body is covered with pollen (yellow areas). The photo was taken using white light
Results of a piecewise structural equation model to assess the effects of light and noise pollution on the pollination components (flower visits, pollen deposition, pollen germination, fruit, and seed set) of Ceiba pentandra in a heavily urbanized habitat on the Yucatan Peninsula. The effects of flowers produced per tree (floral display) and of the surrounding vegetation (green cover) were also assessed. The arrows represent a unidirectional relationship among variables; only those in black represent significant relationships. The number at each arrow is the standardized coefficient; the sign represents the direction of the effects. The asterisks indicate the significance of the coefficients (* P < 0.05, ** P < 0.01, n.s. = not significant). The proportion of variance explained (R²) for each path is shown in the boxes of the endogenous variables
Cities are home to several species of pollinators that play an important role in the reproductive success of wild and cultivated plants that grow in these ecosystems and their surroundings. Pollution is a main driver of pollinator decline. Light and noise pollution are more intense in cities than in any other ecosystem. Although nocturnal pollinators are heavily exposed to these pollutants, their effect on bat pollination is still unknown. Our goal was to assess the effect of light and noise pollution on the main pollination components (pollinator visits, pollen transfer, pollen germination, fruit, and seed set) of the tropical tree, Ceiba pentandra, in a heavily urbanized ecosystem. We measured these components in sites with contrasting intensities of artificial light and anthropogenic noise and statistically assessed the direct and indirect effect of pollutants on pollination components using structural equation modeling. We found that noise and light pollution negatively affected the visits by the bats that pollinate C. pentandra. However, these negative effects did not affect posterior pollination components. In fact, the direct effect of light pollution on reproductive success was positive and greater than the indirect effects via pollinator visits. We suggest that illuminated trees may be able to sustain a large quantity of fruits and seeds because they produce more photosynthates due to greater light radiation and delayed leaf abscission. We conclude that, despite the negative effect of light and noise on pollinator visits, these pollutants did not significantly impact the reproductive success of C. pentandra.
Not all flower-visiting animals act as pollinators; some visitors engage in foraging nectar without pollen transfer. The tendency to rob nectar is related to visitors’ morphological traits and rewards per foraging effort, and drivers of this variation within visitor species are largely unknown. Because foraging behavior is affected by foraging experience, we focused on the relationship between the tendency to rob nectar and the foraging experience of each forager. We investigated five consecutive visits of European honeybee, Apis mellifera L., on comfrey, Symphytum officinale L., in Japan. We estimated the foraging experience of A. mellifera using wing wear, categorized into six groups. Approximately 60% and 40% of A. mellifera foragers engaged in legitimate visits and nectar robbing, respectively. Moreover, most A. mellifera engaged in only one foraging tactic. The proportion of nectar robbing was related to wing wear and was higher in individuals with extensively damaged wings than those with less damaged wings. The present study suggests that extensively experienced honeybee foragers tend towards nectar robbing.
Olfactory response of Aphidius platensis females to sweet pepper and marigold plant treatments at the vegetative stage in a Y-tube olfactometer. Bars indicate the choice by the parasitoid (n = 40), which moved toward the volatile source in the corresponding choice situations. No choice indicates the number of tested individuals that did not make a choice. Chi-square (χ²) test (*P < 0.05, n.s. not significant)
Olfactory response of Aphidius platensis females to sweet pepper and marigold plant treatments at the blooming stage in a Y-tube olfactometer. Bars indicate the choice by the parasitoid (n = 40), which moved toward the volatile sources in the corresponding choice situations. No choice indicates the number of tested individuals that did not make a choice. Chi-square (χ²) test (*P < 0.05, n.s. not significant)
Olfactory response of Aphidius platensis females to sweet pepper and marigold plant treatments at the aphid-infested in a Y-tube olfactometer. Bars indicate the choice by the parasitoid (n = 40), which moved toward volatile sources in the corresponding choice situations. No choice indicates the number of tested individuals that did not make a choice. Chi-square (χ²) test (*P < 0.05, n.s. not significant)
Principal components analysis (PCA) of the composition of volatiles emitted by marigold plants. Vector numbers correspond to compound numbers in Table 1
Principal components analysis (PCA) of the composition of volatiles emitted by sweet pepper plants. Vector numbers correspond to compound numbers in Table 1
The use of nectar-producing companion plants in crops is a well-known strategy of conserving natural enemies in biological control. However, the role of floral volatiles in attracting parasitoids and effects on host location via herbivore-induced plant volatiles is poorly known. Here, we examined the role of floral volatiles from marigold (Tagetes erecta), alone or in combination with volatiles from sweet pepper plant (Capsicum annuum), in recruiting Aphidius platensis, an important parasitoid of the green peach aphid Myzus persicae. We also investigated whether marigold floral volatiles are more attractive to the parasitoid than those emitted by sweet pepper plants infested by M. persicae. Olfactometry assays indicated that floral volatiles attracted A. platensis to the marigold plant and are more attractive than sweet pepper plant volatiles. However, volatiles emitted by aphid-infested sweet pepper were as attractive to the parasitoid as those of uninfested or aphid-infested blooming marigold. The composition of volatile blends released by uninfested and aphid-infested plants differed between both blooming marigold and sweet pepper, but the parasitoid did not discriminate aphid-infested from uninfested blooming marigold. Volatile released from blooming marigold and sweet pepper shared several compounds, but that of blooming marigold contained larger amounts of fatty-acid derivatives and a different composition of terpenes. We discuss the potential implications of the aphid parasitoid attraction in a diversified crop management strategy.
Median values with first and third quartiles (lower and upper hinges) and interval between the smallest and the largest values (whiskers, no further than 1.5*IQR from the hinge) of adult males’ Barkrate (a) and f0 (b) in the three contexts of bark production. Gray lines represent the difference in the median values of Barkrate and f0 for the same adult male between two different contexts of production
Spectrograms of a sequence of barks produced by the same territorial male in standard activity and during a confrontation with another male (a) and the overlaid energy spectrum of one example bark from each context (b)
Behavioral response of subadult males indicated by PC1 scores to playbacks with different Barkrate values (in Hz). Linear regression: F(1,20) = 6.631, p = 0.018, adjusted R² = 0.212
The cape fur seal is one of the most colonial mammal species in the world. Breeding colonies are composed of harems held by mature males (older than 10 years) with up to 30 females and their pups, while roaming subadult males (younger and socially immature) are kept away from bulls’ territories. As in other pinnipeds, cape fur seals are highly vocal and use acoustic signals in all their social interactions. Males produce barks—short vocalizations always produced in sequences—for territorial defense, mating behaviors, and agonistic interactions. These calls convey information about the sex, age class, and individual identity. This study investigated whether motivational cues such as the arousal state can be encoded in territorial males’ barks and whether these cues are decoded by listening sub-adult males. The rate (number of calls per unit of time) and fundamental frequency of barks were found to significantly increase during high arousal state interactions (i.e., male-male confrontation) compared to spontaneous barks. Playback experiments revealed that subadult males responded with a higher level of vigilance when territorial males’ barks had a faster bark rate. This mechanism of decoding the bulls’ arousal state from barks will likely constitute an advantage for both bulls and the subadult males, by avoiding or reducing physical conflicts, and thereby reducing energy expenditure and the risk of injury. This study is the first experimental evidence of cape fur seals’ using vocal rhythmic patterns to modulate their social interactions.
Examining the role of color in mate choice without testing what colors the study animal is capable of seeing can lead to ill-posed hypotheses and erroneous conclusions. Here, we test the seemingly reasonable assumption that the sexually dimorphic red coloration of the male jumping spider Saitis barbipes is distinguishable, by females, from adjacent black color patches. Using microspectrophotometry, we find clear evidence for photoreceptor classes with maximal sensitivity in the UV (359 nm) and green (526 nm), inconclusive evidence for a photoreceptor maximally sensitive in the blue (451 nm), and no evidence for a red photoreceptor. No colored filters within the lens or retina could be found to shift green sensitivity to red. To quantify and visualize whether females may nevertheless be capable of discriminating red from black color patches, we take multispectral images of males and calculate photoreceptor excitations and color contrasts between color patches. Red patches would be, at best, barely discriminable from black, and not discriminable from a low-luminance green. Some color patches that appear achromatic to human eyes, such as beige and white, strongly absorb UV wavelengths and would appear as brighter “spider-greens” to S. barbipes than the red color patches. Unexpectedly, we discover an iridescent UV patch that contrasts strongly with the UV-absorbing surfaces dominating the rest of the spider. We propose that red and black coloration may serve identical purposes in sexual signaling, functioning to generate strong achromatic contrast with the visual background. The potential functional significance of red coloration outside of sexual signaling is discussed.
The evolution of predatory, anti-predatory, and defensive strategies regarding environmental adaptation in animals is of significant research interest. In particular, amphibians, who represent a transition between aquatic and terrestrial vertebrates, play an important role in animal evolution. The bioactive skin secretions of amphibians are of specific interest due to their involvement in the crucial physiological functions of amphibian skin. We previously isolated and identified several bioactive peptides, including those showing antioxidant, antimicrobial, and wound-healing properties, from the skin secretions of the odorous frog species Odorrana andersonii. Currently, however, the biological significance of skin secretions in O. andersonii survival remains unclear. Here, we studied the biological significance of skin glands and secretions in regard to environmental adaptations of O. andersonii. Our research found that O. andersonii may secrete and excrete bioactive secretions through many glands (peptides and proteins as the main components in glands) distributed in the skin. The skin secretions not only displayed toxicity but also showed antioxidant, antibacterial, and repair promoting activities, suggesting that they play a protective role in O. andersonii when facing environmental threats. These bioactive skin secretions appear to act as a chemical survival strategy in O. andersonii, allowing the species to gain advantages in survival behavior.
A mature male of Mnesarete pudica showing the red wing, i.e., the male sexual ornament (a). A mature male perched on a twig showing an opaquer wing (b). A juvenile female showing a smoky black wing (c). A mature female showing a brown wing (d). Picture (b) courtesy of Rogério Machado; (c) courtesy of Carlos Schmidtutz
Chromatic contrast (ΔS) values between Mnesarete pudica (Odonata: Zygoptera) male wings and the wings of conspecific males and females (a); and ΔS values of M. pudica males and females against a savannah visual background (b). The ΔS values are shown in units of JND according to the Receptor Noise Limited model. The dashed line indicates 2.0 JND; the minimum difference assumed that the visual system could discern between two colour patches. Juvenile males cannot be differentiated from mature or juvenile females (‘female mimicry’ hypothesis) (a); nor from the savannah visual background (‘cryptic colouration’ hypothesis) (b)
Chromatic contrast (ΔS) values of Mnesarete pudica (Odonata: Zygoptera) juvenile and sexually mature males’ and females’ wings against a savannah visual background. The ΔS values are shown in units of JND according to the Receptor Noise Limited model. Results are shown according to the visual systems of ultraviolet (UVS) (left to the midline) and violet sensitive (VS) predatory birds (right to the midline). The dashed line indicates 2.0 JND; the minimum difference assumed that the visual system could discern between two colour patches (Table 3)
Female mimicry by males is a widespread phenomenon in several taxa and may be involved in aggression avoidance or facilitated access to resources. In early developmental stages, female mimicry may be a mechanism involved in signalling sexual immaturity or, when coupled with strategies related to visual camouflage, may be involved in the avoidance of male-male agonistic interactions. Here, we addressed whether the delayed colour maturation of a sexual ornament in males of Mnesarete pudica damselflies might be a case of crypsis, female mimicry or both. We analysed how conspecifics and predators perceive the pigmented wings of juvenile males by contrasting the wing spectra against a savannah background and the wings of both juvenile and sexually mature males and females. Our results based on the modelled visual system of conspecifics and predators suggest that the colour maturation of juvenile males may function as both crypsis and female mimicry. We discuss whether these results related to age-and sexual-dichromatism might be a mechanism to avoid unwanted intraspecific interactions or to avoid territorial and aggressive males. We conclude that the female mimicry and crypsis in juvenile males of M. pudica are mechanisms involved in avoidance of predators and unwanted intraspecific interactions, and the signalling of sexual maturity.
Gomesa flexuosa and Janusia guaranitica’s geographical distribution in Brazil, showing the main biomes in the country. Note that both species are widespread and co-occur in Porto Alegre, State of Rio Grande do Sul, Southern Brazil, where our study was performed. Species occurrences used to build the map were obtained from SpeciesLink database (CRIA - Centro de Referência e Informação Ambiental 2021). The data were optimized by removing duplicate coordinates and plotting only Brazilian occurrences in the map (see Tables S2 and S3 in Supplementary Information)
Reproductive structures of Gomesa flexuosa (A–C) and Janusia guaranitica (D–F). A Set of flowers. B Detail of column, pollinarium, callus, and “sac-like” elaiophores (arrows). C Thickened column of a pollinated flower, sealing stigmatic cavity and keeping the anther cap (arrow). D Flowers and their unguiculate petals. E Floral buds and elaiophores (arrow). F Detail of stamens and the central pistil with exposed stigma (arrow). Scale bars = 1 cm
Scheme of the experimental design used to test the hypothesis of Müllerian mimicry between the orchid Gomesa flexuosa and the malpigh Janusia guaranitica, which is a cespitose herb. Each pair of orchids (one inflorescence per individual) was exposed near (1–2 m) and far (20 m) from the focal malpigh. In the near exposure, which lasted for three sunshiny days (consecutive or not), both orchids had only one-third of their flowers open. In the scheme, we are depicting the first flowers to bloom in the inflorescence, while the remaining inflorescence contains only buttons. After the near exposure, the pair of orchids was maintained inside a green house for three consecutive days, during which one-third of the flowers opened, but had no access to pollinators. Finally, in the far exposure, which also lasted three sunshiny days (consecutive or not), both orchids had only one-third of their flowers open. In the scheme, we are depicting the last flowers to bloom in the inflorescence. We highlight, however, that the order of exposure (near vs. far) was randomly assigned to the experimental orchids to avoid any possible bias in the results. Both in the near and far exposures, the total number of open flowers was similar between the orchids and the focal malpigh
Centris trigonoides pollinating Gomesa flexuosa (A–D) and Janusia guaranitica (E–G). A–C Sequential pictures of the bee approaching and landing on orchid flowers. D Site of pollinarium (arrow) attachment, the clypeus. E Bee biting the nail of the petal to stabilize itself on the flower. F Pollen-laden individual. G Bee with orchid pollinarium attached to its head. Scale bars = 1 cm
Results of the field experiment to test the existence of Müllerian mimicry between the orchid Gomesa flexuosa and the Malpighiaceae Janusia guaranitica. Individuals of the orchid were exposed far (20 m) and near (1–2 m) the malpigh. The response variables gathered in the experiment were A probability of bee visitation, B number of contact approximations, C number of visits, and D time of permanence of each bee on the flowers. Bars represent means and errors are standard errors estimated by the models. The asterisk denotes a significant difference (p < 0.05) between the types of exposure
The concept of mimicry has been developed for animals, but it also applies to plants. Plant species may be Müllerian mimics if they have similar reproductive traits and offer similar rewards to the pollinators. Several Oncidiinae orchids offer floral oils to their pollinators and have been suggested to form a Müllerian complex with species of Malpighiaceae. We provide a test of this hypothesis using Gomesa flexuosa (Orchidaceae) and Janusia guaranitica (Malpighiaceae), which are sympatric and phenologically synchronous, secrete the same floral resource (oils), and show similar flower morphology. We exposed individuals of Gomesa near and far from individuals of Janusia and monitored floral visitation. Both species were exclusively pollinated by oil-collecting bees, sharing Centris trigonoides as a pollinator. Nevertheless, the probability of bee visitation, number of contact approximations, and number of visits to flowers of Gomesa were similar when individuals were near and far from Janusia. These findings do not support the Müllerian mimicry hypothesis in these two species. Their resemblances can be better explained by the “exploitation of perceptual biases” hypothesis. According to this hypothesis, pre-existing traits in Oncidiinae orchids (e.g. colour, shape, rewards) may coopt oil-collecting bees that usually search for rewards in Malpighiaceae species with similar flower traits.
Illustration and photomicroscopic view of L. mataybae spatula. a Sketch of the spatula and associated papillae. bLopesia mataybae spatula 0.09 mm long (N = 1), with two apical pointed teeth
L. mataybae galls and galling insect stages. Globoid (female-occupied) and cylindrical (male-occupied) morphotypes induced by L. mataybae on leaflets of Matayba guianensis (a). Female pupa found on the globoid gall (b). Male pupa found on the cylindrical gall (c). Adult female hatched from the globoid morphotype (d). Adult male hatched from the cylindrical morphotype (e). PP pupae, FP female post abdomen, MT male terminalia
L. mataybae gall morphotypes, positioning, and structures. Galls from both morphotypes usually induced on the abaxial leaf surface (a, b). Galls occupied by females (c) have a globoid shape and are larger and thicker laterally than those occupied by males, which have a cylindrical shape (d), despite having the same structure. ALS abaxial leaf surface, VLS vessel-like structure, CCL cocoon-like structure, TC trichomes, LFP L. mataybae female pupa and male pupa (LMP)
Anatomical structure of galls induced by L. mataybae. a, b General overview of gall structures, with the presence of sclerenchyma, typical nutritive tissue, adaxial epidermis, larval chamber, and trichomes from the globoid and cylindrical morphotype, respectively. c, e Female gall. c Female’s base smaller but expanding in thickness around the larval chamber. e Cortex cells resulting from hypertrophy and hyperplasia of the spongy parenchyma, with the presence of vascular bundles. d, f Male gall. d The male base is the larger part, containing more cell layers, and the regions around the larval chamber are thinner. f Vessel-like structure of the cylindrical morphotype, with rounded cells, elongated cells, and trichomes. SC sclerenchyma, TNT typical nutritive tissue, AEP adaxial epidermis, LC larval chamber, TC trichomes, VB vascular bundle, SP spongy parenchyma, ABE abaxial epidermis, RC rounded cells, EC elongated cells
a, b Graphic representation of histometric and cytometric measurements. Elongated/globoid cell layers and elongated/globoid cell area of the globoid and cylindrical morphotypes
In a general way, galling insects can induce only one gall morphotype on the host plant species. However, some taxa of galling insects such as Eriococcidae can induce sexually dimorphic galls on the same host. In the present study, Lopesia mataybae (Diptera: Cecidomyiidae) induced two gall morphotypes on the leaflets of Matayba guianensis (Sapindaceae), a rare evidence of sexual dimorphism in galls induced by Cecidomyiidae. We investigated the adult emergence of galling insects and the morphological, histological and histochemical attributes of the gall morphotypes. Both gall morphotypes showed the galling insect in the larval or pupal stage, and the insect adult emergence from different morphotypes was sexually distinct. Galls occupied by females (Globoid) were significantly larger (average height = 4.67 mm. S=0.43/ average width = 4.59 mm. S=0.70) than galls occupied by males (cylindrical) (average height = 2.95 mm. S=0.46/ average width = 2.34 mm. S=0.45). Both gall types were composed of elongated cells in the inner cortex and rounded cells in the outer cortex of the vessel-like structure. The globoid galls showed 42 cell layers (14 of them cylindrical, S=3.86; 28 rounded S=5.89) and cylindrical galls showed 29 layers. There were no differences between morphotypes in the histochemical compounds detected. We have shown here significant morphological and histological differences between male and female galls possibly due to the different nutritional requirements of Lopesia mataybae sexes. Therefore, the expression of sexual dimorphism in gall morphotypes may be associated with developmental pathway differentiation between the sexes of L. mataybae.
The avian feather combines mechanical properties of robustness and flexibility while maintaining a low weight. Under periodic and random dynamic loading, the feathers sustain bending forces and vibrations during flight. Excessive vibrations can increase noise, energy consumption, and negatively impact flight stability. However, damping can alter the system response, and result in increased stability and reduced noise. Although the structure of feathers has already been studied, little is known about their damping properties. In particular, the link between the structure of shafts and their damping is unknown. This study aims at understanding the structure-damping relationship of the shafts. For this purpose, laser Doppler vibrometry (LDV) was used to measure the damping properties of the feather shaft in three segments selected from the base, middle, and tip. A combination of scanning electron microscopy (SEM) and micro-computed tomography (µCT) was used to investigate the gradient microstructure of the shaft. The results showed the presence of two fundamental vibration modes, when mechanically excited in the horizontal and vertical directions. It was also found that the base and middle parts of the shaft have higher damping ratios than the tip, which could be attributed to their larger foam cells, higher foam/cortex ratio, and higher percentage of foam. This study provides the first indication of graded damping properties in feathers.
Top-cited authors
Fritz Geiser
  • University of New England (Australia)
Dennis VanEngelsdorp
  • University of Maryland, College Park
Wittko Francke
  • University of Hamburg
Galen Dively
  • University of Maryland, College Park
Matthew James Collins
  • University of Copenhagen