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bioRxiv2016

Description of a new genus of primitive ants from Canadian amber, with the study of relationships between crown ants and stem ants (Hymenoptera: Formicidae)

A detailed study of the holotype of Sphecomyrma canadensis Wilson, 1985 from Canadian amber has led to the conclusion that the specimen belongs to a new genus, here named Boltonimecia gen.n. Since the taxonomy of stem-group ants is not well understood, in order to find the taxonomic position of this genus, it is necessary to review the classification of stem-group ants in a study of their relation to crown-group ants. In the absence of data for traditional taxonomic approaches, a statistical study was done based on a morphometric analysis of antennae. Scape elongation is believed to play an important role in the evolution of eusociality in ants; however, this hypothesis has never been confirmed statistically. The statistical analysis presented herein lends support to the view that antennal morphology reliably distinguishes stem-group ants from crown-group ants to determine whether a species belongs to one or the other group. This, in turn, may indicate a relationship exists between eusociality and scape elongation. A review of Cretaceous records of ants is made and the higher classification of Formicidae with definitions of stem and crown groups is proposed. Newly obtained data are discussed focusing particularly on the origin, evolution and diversity of ants.

Zoology↗

bioRxiv2016

Changeover from signalling to energy-provisioning lipids during transition from colostrum to mature milk in the giant panda (Ailuropoda melanoleuca)

Among the large eutherian ( placental) mammals, ursids (bears) give birth to the most altricial neonates with the lowest neonatal:maternal body mass ratios. This is particularly exemplified by giant pandas in whom the transition from colostrum to main-phase lactation is unusually prolonged. To examine whether there is compensation for the provision of developmentally important nutrients that other species groups may provide in utero, we examined colostrum and milk lipids from birth until the transition was complete. Lipids known to be developmental signals or their precursors, and those that are fundamental to nervous system construction, such as docosahexaenoic acid (DHA) and phosphatidylserines containing DHA, appear early and then fall dramatically in concentration to a baseline at about 20 days. This also applies to other signalling lipids such as lysophosphatidylserines. The dynamics of lysophosphatidic acid and eicosanoids display a similar pattern, albeit less clearly and with differences between mothers. Triglycerides occur at relatively low levels initially and then increase in concentration with time post-partum until a plateau is reached at about 30 days or later. These patterns indicate an early provision of signalling lipids and their precursors, and lipids crucial to brain, retinal and central nervous system construction, followed by a changeover to lipids for energy metabolism. Thus, in giant pandas, and possibly among ursids in general, lactation is adapted to provisioning a highly altricial neonate to a degree that approximates to an extension of gestation.

Zoology↗

bioRxiv2016

Quantifying climate change impacts emphasises the importance of managing regional threats in an endangered species

As a global issue the effects of climate change are difficult to manage on a region scale. However, more often than not it is only one of many problems that need to be addressed in species conservation. Non-climatic factors - especially those of anthropogenic origins - play equally if not more important roles with regards to population developments of species and often provide much better toeholds for conservation activities. We examined the population trends of the endangered Yellow-eyed penguin (Megadyptes antipodes) in New Zealand using monitoring data dating back to the 1980s. We developed a Bayesian population model incorporating various climatic factors to assess the relative influence of climate change on the penguin numbers over the past 30 years. Sea surface temperature (SST) proved to be the dominating factor influencing survival of both adult birds and fledglings. Increasing SST since the mid-1990s went along with a reduction in survival rates and population decline. The population model showed that 33% of the variation in population numbers could be explained by SST alone, significantly increasing pressure on the penguin population. Consequently, the population becomes less resilient to nonclimate related impacts, such as fisheries interactions, habitat degradation and human disturbance. But their exact contribution towards population trends is extremely difficult to assess principally due to the absence of quantifiable data. This potentially creates an analysis bias towards climate variables, effectively distracting from non-climate factors that can be managed on a regional scale to ensure the viability of the population.

Zoology↗

bioRxiv2016

Inferring physiological energetics of loggerhead turtle (Caretta caretta) from existing data using a general metabolic theory

Loggerhead turtle is an endangered sea turtle species with a migratory lifestyle and worldwide distribution, experiencing markedly different habitats throughout its lifetime. Environmental conditions, especially food availability and temperature, constrain the acquisition and the use of available energy, thus affecting physiological processes such as growth, maturation, and reproduction. These physiological processes at the population level determine survival, fecundity, and ultimately the population growth rate--a key indicator of the success of conservation efforts. As a first step towards the comprehensive understanding of how environment shapes the physiology and the life cycle of a loggerhead turtle, we constructed a full life cycle model based on the principles of energy acquisition and utilization embedded in the Dynamic Energy Budget (DEB) theory. We adapted the standard DEB model using data from published and unpublished sources to obtain parameter estimates and model predictions that could be compared with data. The outcome was a successful mathematical description of ontogeny and life history traits of the loggerhead turtle. Some deviations between the model and the data existed (such as an earlier age at sexual maturity and faster growth of the post-hatchlings), yet probable causes for these deviations were found informative and discussed in great detail. Physiological traits such as the capacity to withstand starvation, trade-offs between reproduction and growth, and changes in the energy budget throughout the ontogeny were inferred from the model. The results offer new insights into physiology and ecology of loggerhead turtle with the potential to lead to novel approaches in conservation of this endangered species.

Zoology↗

bioRxiv2016

Insects and associated arthropods analyzed during medicolegal death investigations in Harris County, Texas, USA: January 2013- April 2016

The application of insect and arthropod information to medicolegal death investigations is one of the more exacting applications of entomology. Historically limited to homicide investigations, the integration of full time forensic entomology services to the medical examiners office in Harris County has opened up the opportunity to apply entomology to a wide variety of manner of death classifications and types of scenes to make observations on a number of different geographical and species-level trends in Harris County, Texas, USA. In this study, a retrospective analysis was made of 203 forensic entomology cases analyzed during the course of medicolegal death investigations performed by the Harris County Institute of Forensic Sciences in Houston, TX, USA from January 2013 through April 2016. These cases included all manner of death classifications, stages of decomposition and a variety of different scene types that were classified into decedents transported from the hospital (typically associated with myiasis or sting allergy; 3.0%), outdoor scenes (32.0%) or indoor scenes (65.0%). Ambient scene air temperature at the time scene investigation was the only significantly different factor observed between indoor and outdoor scenes with average indoor scene temperature being slightly cooler (25.2{degrees}C) than that observed outdoors (28.0{degrees}C). Relative humidity was not found to be significantly different between scene types. Most of the indoor scenes were classified as natural (43.3%) whereas most of the outdoor scenes were classified as homicides (12.3%). All other manner of death classifications came from both indoor and outdoor scenes. Several species were found to be significantly associated with indoor scenes as indicated by a binomial test, including Blaesoxipha plinthopyga (Sarcophagidae), all Sarcophagidae including B. plinthopyga, Megaselia scalaris (Phoridae), Synthesiomyia nudiseta (Muscidae) and Lucilia cuprina (Calliphoridae). The only species that was a significant indicator of an outdoor scene was Lucilia eximia (Calliphoridae). All other insect species that were collected in five or more cases were collected from both indoor and outdoor scenes. A species list with month of collection and basic scene characteristics with the length of the estimated time of colonization is also presented. The data presented here provide valuable casework related species data for Harris County, TX and nearby areas on the Gulf Coast that can be used to compare to other climate regions with other species assemblages and to assist in identifying new species introductions to the area. This study also highlights the importance of potential sources of uncertainty in preparation and interpretation of forensic entomology reports from different scene types.

Zoology↗

bioRxiv2016

Expression biomarkers used for the selective breeding of complex polygenic traits

We present a novel way to select for highly polygenic traits. For millennia, humans have used observable phenotypes to selectively breed stronger or more productive livestock and crops. Selection on genotype, using single-nucleotide polymorphisms (SNPs) and quantitative trait loci (QTLs), is also now applied broadly in livestock breeding programs; however, selection on protein or mRNA expression markers have not been proved useful yet. Here we demonstrate the utility of protein markers to select for disease-resistant behaviour in the European honey bees (Apis mellifera L.). Robust, mechanistically-linked protein expression markers, by integrating cis and trans effects from many genomic loci, may overcome limitations of genomic markers to allow for selection. After three generations of selection, the resulting stock performed as well or better than bees selected using phenotype-based assessment of this trait, when challenged with disease. This is the first demonstration of the efficacy of protein markers for selective breeding in any agricultural species, plant or animal.\n\nSignificance statementThe honey bee has been in the news a lot recently, largely because of world-wide die-offs due to the parasitic Varroa mite, which is becoming resistant to the chemical controls the bee industry uses. In this study, we show that robust expression biomarkers of a disease-resistance trait can be used, in an out-bred population, to select for that trait. After three generations of selection, the resulting stock performed as well or better than bees selected using the phenotypic best method for assessing this trait when challenged with disease. This is the first demonstration of an expression marker for selective breeding in any agricultural species, plant or animal. This also represents a completely novel way to select for highly polygenic traits.

Zoology↗

bioRxiv2016

A critical review of the use and performance of different function types for modeling temperature-dependent development of arthropod larvae

Temperature-dependent development influences production rates of arthropods, including crustaceans important to fisheries and agricultural pests. Numerous candidate equation types (development functions) exist to describe the effect of temperature on development time, yet most studies use only a single type of equation and there is no consensus as to which, if any model predicts development rates better than the others, nor what the consequences of selecting a potentially incorrect model equation are on predicted development times. In this study, a literature search was performed of studies fitting development functions to development of arthropod larvae (99 species). The published data of most (79) of these species were then fit with 33 commonly-used development functions. Overall performance of each function type and consequences of using a function other than the best one to model data were assessed. Performance was also related to taxonomy and the range of temperatures examined. The majority (91.1 %) of studies were found to not use the best function out of those tested. Using the incorrect model lead to significantly less accurate (e.g., mean difference {+/-} SE 85.9 {+/-} 27.4 %, range: -1.7 to 1725.5 %) predictions of development times than the best function. Overall, more complex functions performed poorly relative to simpler ones. However, performance of some complex functions improved when wide temperature ranges were tested, which tended to be confined to studies of insects or arachnids compared with those of crustaceans. Results indicate the biological significance of choosing the best-fitting model to describe temperature-dependent development time data.\n\nHighlightsO_LITemperature-dependent development functions of arthropod larvae were reviewed\nC_LIO_LI79 published datasets were re-tested and fit with 33 different function types\nC_LIO_LI91.1 % of published studies did not fit their data with the best function of those tested\nC_LIO_LIPerformance differed among functions and was related to taxon and temperature range tested\nC_LIO_LIFunction type impacted predicted development times, so using the best function matters\nC_LI

Zoology↗

bioRxiv2016

How lizards fly: A novel type of wing in animals

Flying lizards of the genus Draco are famous for their gliding ability, using an aerofoil formed by winglike patagial membranes and supported by elongated thoracic ribs. It has remained unknown, however, how the lizards manoeuvre during flight. Here, I show that the patagium is deliberately grasped and controlled by the forelimbs while airborne. This type of composite wing is unique inasmuch as the lift-generating and the controlling units are formed independently by different parts of the body and are connected to each other only for the duration of the flight. The major advantage for the lizards is that the forelimbs keep their entire movement range and functionality for climbing and running when they are not used as the controlling unit of the wing. These findings not only shed a new light on the flight of Draco lizards but also have implications for the interpretation of gliding performance in fossil species.

zoology↗

bioRxiv2016

Mitogenome and nuclear DNA differentiation in spinner (Stenella longirostris) and pantropical spotted dolphins (S. attenuata) from the eastern tropical Pacific Ocean

Spinner dolphins (Stenella longirostris) and spotted dolphins (S. attenuata) show high intraspecific morphological diversity and endemic subspecies in the eastern tropical Pacific Ocean (ETP). Previous studies of mitochondrial DNA (mtDNA) have found low genetic differentiation among most of these groups, possibly due to demographic factors, ongoing gene flow, and/or recent divergence. These species were heavily depleted due to bycatch in the ETP yellowfin tuna fishery. Because population structure is important for accurate management of the recovery of these species, we collected whole mitochondrial genome sequences from 104 spinner and 76 spotted dolphins to test structure hypotheses at multiple hierarchical levels. Our results showed significant differences between subspecies of spotted (FST: 0.0125; P = 0.0402) and spinner dolphins (FST: 0.0133; P = 0.034), but no support for the division of existing offshore stocks of spotted dolphins or Tres Marias spinner dolphins. We compare these results to previous results of genome-wide nuclear SNP data and suggest high haplotype diversity, female dispersal, male philopatry, or relative power of the two datasets explains the differences observed. Our results further support a genetic basis for biologically meaningful management units at the subspecies level, and provide a critical component to mitigating historical and continued fishery interactions.

zoology↗

bioRxiv2016

Evidence for Philopatry and Homing in a New World Elapid Snake

Animal navigation allows individuals to efficiently find and use best available habitats. Despite the long history of research into well-studied taxa (e.g., pigeons, salmon, sea turtles), we know relatively little about squamate navigational abilities. Among snakes, documented philopatry (range maintenance) in a non-colubrid species has been rare. In this study, we document the first example of philopatry and homing in a new world elapid snake, Micrurus apiatus. Our data come from the first multi-year mark-recapture study of this species at the open urban preserve Zoologico Regional Miguel Alvarez del Toro, in Tuxtla Gutierrez, Chiapas, Mexico. We show that on average snakes returned to within 144 m of their last capture point. By releasing snakes in one location, we noted that recaptured individuals preferentially returned to their last capture location, compared to a distribution of random locations in the park. We conclude with a preliminary discussion of the evolution of snake homing and potential mechanisms.

zoology↗

bioRxiv2016

Deploying dengue-suppressing Wolbachia: robust models predict slow but effective spatial spread in Aedes aegypti

A novel strategy for controlling the spread of arboviral diseases such as dengue, Zika and chikungunya is to transform mosquito populations with virus-suppressing Wolbaehia. In general, Wolbachia transinfected into mosquitoes induce fitness costs through lower viability or fecundity. These maternally inherited bacteria also produce a frequency-dependent advantage for infected females by inducing cytoplasmic incompatibility (CI), which kills the embryos produced by uninfected females mated to infected males. These competing effects, a frequency-dependent advantage and frequency-independent costs, produce bistable Wolbachia frequency dynamics. Above a threshold frequency, denoted p, CI drives fitness-decreasing Wolbachia transinfections through local populations; but below p, infection frequencies tend to decline to zero. If p is not too high, CI also drives spatial spread once infections become established over sufficiently large areas. We illustrate how simple models provide testable predictions concerning the spatial and temporal dynamics of Wolbachia introductions, focusing on rate of spatial spread, the shape of spreading waves, and the conditions for initiating spread from local introductions. First, we consider the robustness of diffusion-based predictions to incorporating two important features of wMel-Aedes aegypti biology that may be inconsistent with the diffusion approximations, namely fast local dynamics induced by complete CI (i.e., all embryos produced from incompatible crosses die) and long-tailed, non-Gaussian dispersal. With complete CI, our numerical analyses show that long-tailed dispersal changes wave-width predictions only slightly; but it can significantly reduce wave speed relative to the diffusion prediction; it also allows smaller local introductions to initiate spatial spread. Second, we use approximations for[p] and dispersal distances to predict the outcome of 2013 releases of wMel-infected Aedes aegypti in Cairns, Australia, Third, we describe new data from Aedes aegypti populations near Cairns, Australia that demonstrate long-distance dispersal and provide an approximate lower bound on p for wMel in northeastern Australia. Finally, we apply our analyses to produce operational guidelines for efficient transformation of vector populations over large areas. We demonstrate that even very slow spatial spread, on the order of 10-20 m/month (as predicted), can produce area-wide population transformation within a few years following initial releases covering about 20-30% of the target area.

zoology↗

bioRxiv2017

Challenges in identifying and interpreting organizational modules in morphology

Form is a rich concept that agglutinates information about the proportions and topological arrangement of body parts. Modularity is readily observable in both the variation of proportions (variational modules) and the organization of topology (organizational modules). The study of variational modularity and of organizational modularity faces similar challenges regarding the identification of meaningful modules and the validation of generative processes; however, most studies in morphology focus solely on variational modularity, while organizational modularity is much less understood. A possible cause for this bias is the successful development in the last twenty years of morphometrics, and specially geometric morphometrics, to study patters of variation. This contrasts with the lack of a similar mathematical framework to deal with patterns of organization. Recently, a new mathematical framework has been proposed to study the organization of anatomical parts using tools from Network Theory, so-called anatomical network analysis. This essay explores the potential use of this new framework - and the challenges it faces in identifying and validating biologically meaningful modules in morphological systems -, by providing an example of a complete analysis of modularity of the human skull and upper limb. Finally, we suggest further directions of research that may bridge the gap between variational and organizational modularity studies.

zoology↗

bioRxiv2017

Euthecosomata (Mollusca, Gastropoda, Thecosomata). Taxonomic review

The Euthecosomata Meisenheimer, 1905, holoplanktonic Mollusca with coiled or straight shell were respectively classified in Limacinoidea Gray, 1847 and Cavolinioidea Gray, 1850. In a biometrical analysis (Rampal 1973) a first change had occurd in this last superfamily: the conica shell genera Creseis Rang, 1828, Boasia Dall, 1889, Styliola Gray, 1850 and Hyalocylis Fol, 1875 were gathered into the Creseidae Rampal, 1973. Therefore it was necessary to carry on this study using molecular data. Our recent cladistic and molecular analyses as well as palaeontologic data led to a systematic and phylogenetic revision of the Euthecosomata: the Limacinoidea and of the Creseidae are not monophyletic, the other straight shells Euthecosomata are monophyletic (Corse et al. 2013).\n\nThe Limacinoidea are invalidated; they are split into three families: Limacinidae Gray, 1847, Heliconoididae n. fam. and Thieleidae n. fam. The Creseidae Rampal, 1973 are validated but at least there are two genera Creseis Rang, 1828 and Boasia Dall, 1889; Styliola and Hyalocylis are considered incertae sedis. In the Cavoliniidae Gray, 1850 there are four subfamily: Cuvierininae Gray, 1850, Cliinae Jeffreys, 1869, Diacriinae n. subfam., Cavoliniinae Gray, 1850. The Creseidae Rampal, 1973 and the Cavoliniidae Gray, 1850 belong to the Cavolinioidea Gray, 1850. The species rank of most taxa is confirmed. New genera are proposed or reinstated: Telodiacria n. gen., Hyalaea de Blainville, 1821, Boasia Dall, 1889. The fossil Vaginella Daudin, 1800 is included within the Cuvierininae Gray, 1847. The spiral fossil Altaspiratella Korobkov, 1966 is no longer considered part of the Limacinidae Gray, 1847.\n\nTwo phylogenetic hypotheses are analysed. According to molecular analyses in COI there is the double emergency of straight shell from two coiled shell lineages; in 28S there is monophyly; this last hypothesis we have kapt is the most parsimonious but requires some reserve and new investigations (Corse et al. 2013).

zoology↗

bioRxiv2017

Behavioral responses of household ants (Hymenoptera) to odor of different coffee species and formulations: Sustainability approach for green pest management strategies

Odor sensation is a sensory modality of considerable significance in the foraging behavior and interactional organization of ants. In the food bait technology, smell is the basis of attraction, which in turn, is the initial line of bait use and a key parameter for judging efficacy. Yet, baits that are currently available possess low attractiveness to many ant pests. Hence, strategies to produce ant bait with increased attractiveness are needed. Despite evidence that coffee has a diverse aroma complex that affects the behavior of honey bees, which share many social and genetic traits with ants, its attraction to formicine foragers have yet to be investigated. In a series of Y-tube olfactometer bioassays, we examined the behavioral responses of Tapinoma indicum (TI), Monomorium pharaonis (MP) and Solenopsis geminata (SG) to various coffee-induced odor stimuli, comprised of extracts from Arabica, Robusta and Liberica. All coffee species showed an influence on the behavior of TI, MP and SG workers, but the clearest effect was seen with Arabica. The workers of TI, MP and SG were more attracted to the odor of 0.01% Arabica extract (ONE), in comparison with 0.05% Arabica extract (TWO) or 0.05% Arabica extract (THREE). Arabica extract mixed with sugar (S) elicited significant attraction from workers of all three species when in balanced competition with either unsweetened Arabica extract or water. These results indicate that coffee, particularly Arabica is attractive to the foragers of TI, MP and SG, and can encourage the use of coffee in bait development. As coffee is already accepted in most human societies, the development of coffee-based bait may be an attractive option.

zoology↗

bioRxiv2017

No evidence for avoidance of black rat scent by the presumably less competitive Natal multimammate mouse in a choice experiment

In Africa, indigenous multimammate mice (Mastomys natalensis) only appear to live commensally in houses when invasive black rats (Rattus rattus) are absent, yet little is known about the underlying mechanism. Avoidance through smell may cause the absence of M. natalensis from areas occupied by R. rattus, but this hypothesis has not yet been tested. We conducted a Y-maze choice experiment where 15 M. natalensis were offered a choice between corridors containing conspecific scent, R. rattus scent, and a control scent. Residence time in the R. rattus corridor was greater than that in the control corridor but equal to that in the M. natalensis corridor, suggesting that multimammate mice do not actively avoid the scent of their invasive competitor.

zoology↗

bioRxiv2017

Neotrygon vali (Myliobatoidei: Dasyatidae), a new blue-spotted maskray from the Solomon archipelago described from its DNA barcode

The blue-spotted maskray from Guadalcanal Island (Solomon archipelago) is distinct by its colour patterns from Neotrygon kuhlii with which it was previously confused, and belongs to a genetic lineage clearly separate from all other known species in the genus Neotrygon. It is here described as a new species, Neotrygon vali sp. nov., on the basis of its nucleotide sequence at the cytochrome oxidase 1 (CO1) gene locus. It is diagnosed from all other known species in the genus Neotrygon by the possession of nucleotide T at nucleotide site 420 and nucleotide G at nucleotide site 522 of the CO1 gene.

zoology↗

bioRxiv2017

Oxygen consumption rate in Gasterosteus aculeatus-Schistocephalus solidus system from a non-migratory naturally infected population.

The three spine stickleback Gasterosteus aculeatus is a specific obligatory intermediate host for the cestode worm Schistocephalus solidus. This system is commonly used to investigate the host-parasite interaction in fishes. Despite the interesting attempts which have been made to quantify the impact of the parasite over the respiration rate of the host fish, none of the previous reports took in consideration that stickleback is diversified in different ecotypes according to its ability to made reproductive migration, from and to the sea. Here the oxygen consumption rate in specimens of three-spine stickleback collected from a non-migratory population was quantified with the aim to test if the S. solidus infection drives a change in the oxygen consumption level of the host fish. The results showed that the infected fishes have a higher rate of oxygen consumption compared with the uninfected one. The differences were due to a direct effect of the parasite, not merely to its contribution to the whole oxygen consumption rate. The data were compared with previous reports, showing that the non-migratory population was characterized by a different level of oxygen consumption rate. The differences were interpreted in terms of divergence in physiological adaptations which had to be appeared in different populations.

zoology↗

bioRxiv2017

Morphological Alternations of Intraepithelial and Stromal Telocytes in Response to Salinity Challenges

Summary statementThe article represent an experimental study in which we investigated the effect of the ssalinty on the communicating cells (telocytes) and their target cells including chloride, stem, Rodlet cells, myoblasts\n\nAbstractTelocyte is a communicating cell established relations to various types of cells. Few experimental studies are performed on telocytes. The current study investigated responce of telocytes to salinity stress in relations to osmoregualtory, immune and stem cells. We exposed Common carp to salinity level 0.2, 6, 10, 14 ppt. Gill samples were fixed and processed for microscopic and TEM. Two types of telocytes were identified: intraepithelial and stromal telocytes. Intraepithelial telocytes comprised the cellular lining of the lymph spaces where they shed the secretory vesicles. Stromal telocytes shed their secretory vesicles in the secondary circulatory vessels. Telocyte enlarged and exhibited high secretory activities. They exert their effect either by direct contact or by paracrine mode. In sanity treated samples, chloride cells enlarged and the mitochondria became cigar-shaped. pavement cells enlarged and micro-ridges elongated. Stromal telocytes established contact with stem cell and skeletal myoblast. Macrophages and Rodlet cells increased in number. In conclusion, intraepithelial and stromal responded to salinity stress by activation of cellular signaling. They play a major role in osmoregulation, immunity, and regeneration.

zoology↗