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bioRxiv2015

The Moose of Isle Royale: An Unnatural Condition?

The now iconic moose of Isle Royale National Park arrived on the island sometime between 1910 and 1915 (Hickie, 1936; Murie, 1934). Prior to that period there is no evidence of moose in either naturalist reports or in the archaeological history of the island (Murie, 1934; Scarpino, 2011). Early naturalists-while observing the moose during their first 20 years on the island--noted both their dramatic expansion, and equally dramatic population crash in the 1930s, see Figure 1. Around 1950, and just as the moose were rebounding, wolves crossed a frozen Lake Superior and began what is now one of our most emblematic predator/prey systems (Peterson, 1995). Recently, the wolves on Isle Royale appear headed for local extinction (Mlot, 2015). Calls to repopulate the island have renewed the vigorous debate surrounding what is and what is not wild about Isle Royale (Scarpino, 2011; Cronon, 1996; Nelson & Callicott, 2008; Cronon, 2003; Peterson, 1999).\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC=\"FIGDIR/small/019984_fig1.gif\" ALT=\"Figure 1\">\nView larger version (12K):\norg.highwire.dtl.DTLVardef@1fd3c26org.highwire.dtl.DTLVardef@77f332org.highwire.dtl.DTLVardef@ff6d66org.highwire.dtl.DTLVardef@1675891_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO The early population dynamics of moose on Isle Royale. Estimates of moose population size were taken from early naturalist reports of Isle Royale (see map for the islands location). The points indicate the average trend and the shaded region represents the reported discrepancy. The lower bound of the shaded region represents the actual value reported in the literature and were used for model fitting.\n\nC_FIG

Zoology↗

bioRxiv2015

Phylogenetic relationships of the Helmeted Woodpecker (Dryocopus galeatus): A case of interspecific mimicry?

Examples of phenotypic convergence in plumage coloration have been reported in a wide diversity of avian taxonomic groups, yet the underlying evolutionary mechanisms driving this phenomenon have received little scientific inquiry. Herein, we document a striking new case of plumage convergence in the Helmeted Woodpecker (Dryocopus galeatus) and explore the possibility of visual mimicry among Atlantic Forest woodpeckers. Our multi-locus phylogenetic analyses unequivocally place D. galeatus within Celeus, indicating the former has subsequently converged in appearance upon the distantly related and syntopic Dryocopus lineatus, to which it bears a remarkable resemblance in plumage coloration and pattern. Although details of the Helmeted Woodpeckers ecology and natural history are only now beginning to emerge, its smaller size and submissive behavior are consistent with predictions derived from evolutionary game theory models and the interspecific social dominance mimicry hypothesis (ISDM). Moreover, estimates of avian visual acuity suggest that size-related mimetic deception is plausible at distances ecologically relevant to Celeus and Dryocopus foraging behavior. In light of our results, we recommend taxonomic transfer of D. galeatus to Celeus and emphasize the need for detailed behavioral studies that examine the social costs and benefits of plumage convergence to explicitly test for ISDM and other forms of mimicry in these Atlantic Forest woodpecker communities. Future field studies examining potential cases of competitive mimicry should also take into account the mimics acoustic behavior, particularly in the presence of putative model species and other heterospecific competitors, as any discontinuity between morphological and behavioral mimicry would likely preclude the possibility of deception.

Zoology↗

bioRxiv2015

The rediscovery of Strix butleri (Hume, 1878) in Oman and Iran, with molecular resolution of the identity of Strix omanensis Robb, van den Berg and Constantine, 2013

BackgroundMost species of owls (Strigidae) represent cryptic species and their taxonomic study is in flux. In recent years, two new species of owls of the genus Strix have been described from the Arabian peninsula by different research teams. It has been suggested that one of these species, S. omanensis, is not a valid species but taxonomic comparisons have been hampered by the lack of specimens of S. omanensis, and the poor state of the holotype of S. butleri.\n\nMethodsHere we use new DNA sequence data to clarify the taxonomy and nomenclature of the S. butleri complex. We also report the capture of a single S. butleri in Mashhad, Iran.\n\nResultsA cytochrome b sequence of S. omanensis was found to be identical to that of the holotype of S. butleri, indicating that the name S. omanensis is best regarded as a junior synonym of S. butleri. The identity of the S. butleri captured in Mashhad, Iran, was confirmed using DNA sequence data. This represents a major (1,400 km) range extension of this species.\n\nConclusionsThe population discovered in Oman in 2013 and originally named S. omanensis actually represents the rediscovery of S. butleri, which was known from a single specimen and had not been recorded since 1878. The range of S. butleri extends into northeast Iran. Our study augments the body of evidence for the recognition of S. butleri and S. hadorami as separate species and highlights the importance of using multiple evidence to study cryptic owl species.

Zoology↗

bioRxiv2015

Distribution and abundance of the West Indian manatee (Trichechus manatus) in the Panama Canal

The West Indian manatee (Trichechus manatus) is threatened throughout its distribution, and is categorized as vulnerable by IUCN (Lefebvre 2001, IUCN 2007). The number of mature individuals is currently estimated at less than 10,000 and is expected to decline at a rate of at least 10% over the next 20 years as a result of both habitat loss and anthropogenic factors (Deutsch et al. 2008). While the West Indian manatee is the most widespread of all existing sirenians, some populations are estimated at fewer than 10 individuals (Deutsch et al. 2008, Quintana-Rizzo and Reynolds 2010). In addition, in most Central American countries reliable information on manatee distribution and conservation status is missing and there is need to assess these remnant populations to guide future management strategies.

Zoology↗

bioRxiv2015

Blood circulation in the tunicate Corella inflata (Corellidae).

The ascidian tunicate Corella inflata is relatively transparent compared to other solitary tunicates and the circulatory system can be visualized by injecting high molecular weight fluorescein labeled dextran into the beating heart or the large vessels at the ends of the heart. In addition, after staining with neutral red the movement of blood cells can be followed to further define and characterize the circulatory system. The heart is a gently curved tube with a constriction in the middle and extends across the width of the animal. As in other tunicates, pumping is peristaltic and periodically reverses direction. During the abvisceral directional phase blood leaves the anterior end of the heart in two asymmetric vessels that connect to the two sides of the branchial basket (or pharynx), in contrast to the direct connection between the heart and the endostyle seen in the commonly studied tunicate Ciona intestinalis. In Corella inflata blood then flows in both transverse directions through a complex system of ducts in the branchial basket into large ventral and dorsal vessels and then to the visceral organs in the posterior of the animal. During the advisceral phase blood leaves the posterior end of the heart in vessels that repeatedly bifurcate to fan into the stomach and gonads. Blood speed, determined by following individual cells, is high and pulsatory near the heart, but decreases and becomes more constant in peripheral regions. Estimated blood flow volume during one directional phase is greater than the total volume of the animal. Circulating blood cells are confined to vessels or ducts in the visible parts of the animal and retention of high molecular weight dextran in the vessels is comparable to that seen in vertebrates. These flow patterns are consistent with a closed circulatory network.

Zoology↗

bioRxiv2015

Changes in the milk metabolome of the giant panda (Ailuropoda melanoleuca) with time after birth: Three phases in early lactation and progressive individual differences

Ursids (bears) in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1-6 (Phase 1), days 7-20 (Phase 2), and beyond day 20 (Phase 3). While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth.

Zoology↗

bioRxiv2015

Biomechanics of shear-sensitive adhesion in climbing animals: peeling, pre-tension and sliding-induced changes in interface strength

Rapid control of adhesive forces is one of the key benchmarks where footpads of climbing animals outperform conventional adhesives, promising novel bio-inspired attachment systems. All climbing animals use shear forces to switch rapidly between firm attachment and easy detachment, but the detailed mechanisms underlying shear-sensitive adhesion have remained unclear. Here, we show that attachment forces of stick insects follow classic peeling theory when shear forces are small, but strongly exceed predictions as soon as their pads start to slide due to high shear forces. Pad sliding dramatically increases the critical peel force via a combination of two distinct mechanisms. First, partial sliding will pre-stretch the pads, so that they are effectively stiffer upon detachment and peel increasingly like inextensible tape. We demonstrate how this effect can be directly related to peeling theories which account for frictional dissipation. Second, pad sliding reduces the thickness of the secretion layer in the contact zone, thereby decreasing the interfacial mobility, and increasing the stress levels required for peeling. The approximately linear increase of adhesion with friction results in a sharp increase of adhesion at peel angles less than ca. 30{degrees}, allowing rapid switching between attachment and detachment during locomotion. Our results may apply to diverse climbing animals independent of pad morphology and adhesive mechanism, and highlight that control of adhesion is not solely achieved by direction-dependence and morphological anisotropy, suggesting promising new routes for the development of bio-inspired adhesives.

Zoology↗

bioRxiv2015

Phenotypes in insect biodiversity research

Introduction Introduction Phenotype data: past and... Phenotype data: present and... Challenges and future directions References Phenotypes, here defined as the observable characteristics of organisms, including morphology, behavior, and physiological products (e.g., nests and galls)--the results of gene expression, in an environment--are the primary data for research on the evolution and taxonomy of insects (Deans et al., 2012a). The shapes, textures, colors, or simply the presence or absence of anatomical features or behaviors help us determine taxa and guide our hypotheses regarding their evolutionary history. Phenotype data are relevant to most other research on insects as well, including biomechanics (Labonte and Federle, 2015), bioinspired engineering ( ...

Zoology↗

bioRxiv2015

Evidence of adoption, monozygotic twinning, and low inbreeding rates in a large genetic pedigree of polar bears

Multigenerational pedigrees have been developed for free-ranging populations of many species, are frequently used to describe mating systems, and are used in studies of quantitative genetics. Here, we document the development of a 4449-individual pedigree for the Western Hudson Bay subpopulation of polar bears (Ursus maritimus), created from relationships inferred from field and genetic data collected over six generations of bears sampled between 1966 and 2011. Microsatellite genotypes for 22-25 loci were obtained for 2945 individuals, and parentage analysis was performed using the program FRANO_SCPLOWZC_SCPLOW, including additional offspring-dam associations known only from capture data. Parentage assignments for a subset of 859 individuals were confirmed using an independent high-density set of single nucleotide polymorphisms. To account for unsampled males in our population, we performed half-sib-full-sib analysis to reconstruct males using the program COLONY, resulting in a final pedigree containing 2957 assigned maternities and 1861 assigned paternities with only one observed case of inbreeding between close relatives. During genotyping, we identified two independently captured two-year-old males with identical genotypes at all 25 loci, showing--for the first time--a case of monozygotic twinning among polar bears. In addition, we documented six new cases of cub adoption, which we attribute to cub misidentification or misdirected maternal care by a female bereaved of her young. Importantly, none of these adoptions could be attributed to reduced female vigilance caused by immobilization to facilitate scientific handling, as has previously been suggested.

Zoology↗

bioRxiv2015

Structural specialities, curiosities and record-breaking features of crustacean reproduction

Crustaceans are a morphologically, physiologically and ecologically highly diverse animal group and correspondingly diverse are their reproductive characteristics. They have evolved structural specialities with respect to penis construction, sperm form, sperm storage, fertilization and brood care. Unique in the animal kingdom are safety lines that safeguard hatching and first molting. Further curiosities are dwarf males in parasitic and sessile taxa and bacteria-induced gigantism and infectious feminization in crustacean hosts. Record-breaking features in animals are relative penis length, clutch size, sperm size, chromosome number, viability of resting eggs, and fossil ages of penis, sperm and brooded embryos. These reproductive peculiarities are reviewed and their implication for basic and applied biology is discussed, including the early evolution and diversification of brood care in arthropods, sperm competition and assurance of paternity, posthumous paternity and sustainable male-based fishery, and ecotype changes by man-made pollution.

Zoology↗

bioRxiv2015

New records of Atlantic humpback dolphin in Guinea, Nigeria, Cameroon and Togo underscore fisheries pressure and generalised marine bushmeat demand

In northern Guinea, we sighted two groups of Sousa teuszii (n=25; n=40 dolphins) off the Tristao Islands during exploratory small-boat surveys in 2011-12. Based on these and recent (2013) observations in the contiguous Rio Nunez estuary, we propose a single Guineas stock, combining the former Rio do Jeba-Bijagos and South Guinea stocks. Significant mortality of S. teuszii from fisheries interactions is widely recognised however not quantifiable as monitoring effort is sporadic. In Guinea, catches were documented in 2002 (n=1) and in 2011-12 (n=5). Landed specimens were recorded in Cameroon (n=2) and Nigeria (n=2). All individuals were killed in small-scale coastal fisheries, presumably as accidental net entanglements, though directed takes cannot be excluded. All landed dolphins were butchered for human consumption (marine bushmeat). Nigerian fishers indicated also an alternative use as shark bait. If local markets in cetacean bushmeat and bait develop, as in Ghana, that will exacerbate pressures by encouraging directed takes. Catch records in Nigeria and sightings in Togo authenticate both nations as (long-suspected) range states for S. teuszii, a belated documenting of the primary, historical distribution. The Gulf of Guinea stock ( Cameroon dolphins) extends at least from Togo to southern Cameroon, and probably into Equatorial Guinea. However, rare sightings of small groups point to remnant, not thriving, dolphin communities. We anticipate de novo distribution gaps emerging and consolidating, following decades of fisheries interactions and creeping encroachment on once pristine coastal habitat. Developed coastlines in Ghana and Cote dIvoire devoid of records may already constitute such gaps. As the lack or scarcity of records warn about formidable challenges to the long-term survival of S. teuszii, innovative, workable protection measures are needed, soonest. We recommend the implementation of several new border-straddling marine protected areas (cf. Saloum Delta-Niumi National Park Complex) which could bring forth a major conservation effect. Binational involvement bears obvious advantages, from sharing responsibilities and allowing for larger protected areas. Suggested dolphin sanctuary examples could include MPAs straddling borders between Cameroon/Equatorial Guinea and Guinea-Bissau/Guinea-Conakry.

Zoology↗

bioRxiv2016

Physiological reason for ceasing growth of unfertilized eggs produced by unmated queens in the subterranean termite Reticulitermes chinensis

In Reticulitermes chinensis, a close relative of R. speratus with asexual queen succession, unfertilized eggs can be produced but are not incubated. To explain this phenomenon, we analysed the physiological differences between unfertilized eggs/unmated queens and fertilized eggs/mated queens. Fertilized eggs consumed significantly larger quantities of five amino acids (Cys, Met, Ile, Leu and Tyr), Ca, protein and cholesterol during incubation. The higher levels of four trace elements (Na, K, Zn and Fe) in fertilized eggs and their lower levels in mated queens indicated that mated queens might transfer these trace elements to fertilized eggs to complete incubation. The higher levels of Mn, triglycerides and serotonin in mated queens and higher levels of Mn and glucose in fertilized eggs suggested that these substances are very important for normal ovarian and embryonic growth. The different expression of three reproductive genes (vtgl, rabil and JHE1) suggested that they might be involved in the regulation of ovarian and embryonic growth. Overall, changes in these physiological indices may substantially affect ovarian and embryonic growth and prohibit the incubation of unfertilized eggs in R. chinensis.

Zoology↗

bioRxiv2016

Nuclear and mitochondrial phylogeny of Rossella (Hexactinellida: Lyssacinosida, Rossellidae): a species and a species flock in the Southern Ocean

Hexactinellida (glass sponges) are abundant and important components of Antarctic benthic communities. However, the relationships and systematics within the common genus Rossella Carter, 1872 (Lyssacinosida: Rossellidae) are unclear and in need of revision. The species content of this genus has changed dramatically over the years depending on the criteria used by the taxonomic authority consulted. Rossella was formerly regarded as a putatively monophyletic group distributed in the Southern Ocean and the North Atlantic. However, molecular phylogenetic analyses have shown that Rossella is restricted to the Southern Ocean, where it shows a circum-Antarctic and subantarctic distribution. Herein, we provide a molecular phylogenetic analysis of the genus Rossella, based on mitochondrial (16S rDNA and COI) and nuclear (28S rDNA) markers. We corroborate the monophyly of Rossella and provide evidence supporting the existence of one species, namely Rossella antarctica Carter, 1872 and a species flock including specimens determined as Rossella racovitzae Topsent, 1901, Rossella nuda Topsent, 1901, Rossella fibulata Schulze & Kirkpatrick, 1910, and Rossella levis (Kirkpatrick, 1907).

Zoology↗

bioRxiv2016

Omura’s whale (Balaenoptera omurai) stranding on Qeshm Island, Iran: further evidence for a wide (sub)tropical distribution, including the Persian Gulf

A small, juvenile rorqual live-stranded on Qeshm Island, Iran, in the northern Strait of Hormuz (Persian Gulf) in September 2007. Cause of stranding remains unknown but the whale (QE22.09.2007) showed no severe traumatic injuries nor was emaciated. Based on at least seven morphological features, considered diagnostic in combination, allowed a positive identification as Omuras whale Balaenoptera omurai. Features included diminutive body size (397 cm), a large number of ventral grooves (n=82) extending caudad of the umbilicus, a strongly falcate dorsal fin, asymmetric colouration of the head (especially lower jaws) reminiscent of fin whale, including three unilateral dark stripes, faint/incomplete lateral rostral ridges, record low number of short, broad baleen plates (204 in right jaw). The likelihood for the existence of a local B. omurai population in the eastern Persian Gulf or northern Arabian Sea seems higher than the wandering of a very young animal or mother/calf pair from any of the known distant distribution areas in the eastern Indian Ocean or SW Indian Ocean (Madagascar). This is the first record of B. omurai in the NW Indian Ocean.

Zoology↗

bioRxiv2016

A NEW SPECIES OF SEEDEATER (EMBERIZIDAE: SPOROPHILA) FROM THE IBERA GRASSLANDS, IN NORTHEAST ARGENTINA

We describe a new species of capuchino of the genus Sporophila (Emberizidae) of the Esteros del Ibera, province of Corrientes, in northeastern Argentina. This species would have remained unidentified due to lack of ornithological explorations in the central area of the Esteros del Ibera. It has been confused with immature individuals of other Sporophila species. We made observations of behavior and habitat, playback experiments, comparative analyzes of the vocalizations and plumage with other sympatric species of the same genus, and we found this species, which we have named Sporophila iberaensis, inhabiting wet grasslands from the edges of the marshes, having a unique vocal repertoire and a unique plumage. Because of its restricted geographical distribution and the threats that have their habitat, this new species should be categorized as Vulnerable on the IUCN Red List.

zoology↗

bioRxiv2016

Fate of glair glands and oocytes in unmated crayfish: a comparison between gonochoristic slough crayfish and parthenogenetic marbled crayfish

In the period before spawning, freshwater crayfish females develop glair glands on the underside of the pleon. These glands produce the mucus for a transient tent-like structure in which the eggs are fertilized and attached to the pleopods. Long-term observation of females of the bisexually reproducing slough crayfish, Procambarus fallax, kept in captivity revealed that glair glands developed in late winter and late summer of each year independent of the presence of males. However, in contrast to mated females unmated females did neither form a fertilization tent nor spawn. Their glair glands persisted for an unusually long period of time and disappeared only during the next moult. Apparently, females use information on sperm availability to either reproduce or save the resources. Marbled crayfish, Procambarus virginalis, a parthenogenetic descendant of slough crayfish, developed glair glands in approximately the same periods of the year but spawned despite of the absence of mating. These findings indicate that on their way from gonochorism to parthenogenesis regulation of glair gland activity and spawning has been decoupled from mating. Therefore, the species pair Procambarus fallax/Procambarus virginalis seems to be particularly suitable to investigate the physiological, molecular and genetic mechanisms underlying spawning in freshwater crayfish.

Zoology↗

bioRxiv2016

Physiological and biochemical changes associated with experimental dehydration in the desert adapted cactus mouse, Peromyscus eremicus

Characterizing traits critical for adaptation to a given environment is an important first step in understanding how phenotypes evolve. How animals adapt to the extreme heat and aridity commonplace to deserts represents is an exceptionally interesting example of these processes, and has been the focus of study for decades. In contrast to those studies, where experiments are conducted on either wild animals or captive animals held in non-desert conditions, the study described here leverages a unique environmental chamber that replicates desert conditions for captive Peromyscus eremicus (cactus mouse). Here we establish baseline values for daily water intake and for serum electrolytes, as well as the response of these variables to experimental dehydration. In brief, P. eremicus daily water intake is very low. Its serum electrolytes are distinct from many previously studied animals, and its response to acute dehydration is profound, though not suggestive of renal impairment, which is atypical of mammals.\n\nSummary statementThe establishment of baseline values for serum electrolytes and water intake, as well as their response to acute dehydration is critical for characterizing the physiology necessary for desert survival.\n\nConflict of Interest StatementThe authors declare no conflict of interest.

Zoology↗

bioRxiv2016

All alloparents are not equally valuable: Primary breeders and group size explain group reproductive success in cooperatively breeding primates

Prior research on cooperative breeders has considered correlations between group reproductive output (GRO) and the number of individuals in each age-sex class, but without controlling for uneven sampling efforts, the underlying effects of group size, and pseudoreplication at the group and species levels. Among callitrichids, age-sex classes do not provide meaningful categories, as individuals within an age-sex class can demonstrate varying reproductive development due to reproductive dominance of a few individuals per group. This study re-assesses the drivers of GRO in callitrichids by a) conducting a meta-analysis of published studies of callitrichid group composition; b) determining a novel method to assign developmental class based on reproductive morphology; and c) utilizing a multistep modelling approach to assess whether any sex-based developmental class predicts both the presence and the numbers of surviving offspring among free-ranging saddleback (Leontocebus weddelli) and emperor tamarins (Saguinus imperator) in Peru. The meta-analysis utilizing a historical dataset revealed that adult females and group size, but not the number of adult males is significantly correlated with GRO. Statistical models of the new dataset revealed that only mature males predicted if groups had any infants at all, but that the number of surviving infants was predicted by mature females and group size. Thus mature males appear to be necessary for groups to raise any infants, but mature females and a larger group size increase group reproductive output overall.

Zoology↗