The Ontogeny of Neonesidea oligodentata (Bairdioidea, Ostracoda, Crustacea)

This is the first detailed ontogenetic study of the appendages and carapace of a bairdioidean ostracod. This paper uses the development of the appendages and changes in the pore systems of the carapace through ontogeny to help determine the relationship between the Bairdioidea and other podocope groups. Neonesidea oligodentata has eight post-embryonic stages: one fewer than the Cypridoidea, Cytheroidea and Darwinuloidea. The first instar of N. oligodentata resembles that of the second instar of the Cypridoidea and Cytheroidea in terms of appendages, and it is postulated that there is an additional instar stage of N. oligodentata that molts within the egg. The general sequence of appearance of the limbs from instar A-7 onwards is similar to that of the Cypridoidea and Cytheroidea, but different from that of the Darwinuloidea. Like the Cypridoidea and Cytheroidea, N. oligodentata has a gap in its ontogenetic development during instar A-6, where no new Anlage is added. Pore system analysis of A-7 instars suggests that the Bairdioidea may be more closely related to the Cypridoidea than to the Cytheroidea.     

A new commensal ostracod <Emphasis Type="Italic">Asterositus ohtsukai</Emphasis> n. g., n. sp. (Paradoxostomatidae) on the sea star <Emphasis Type="Italic">Sclerasterias euplecta</Emphasis> (Fisher) (Asteriidae) and its feeding habits

A new commensal ostracod Asterositus ohtsukai n. g., n. sp. (Podocopida: Cytheroidea: Paradoxostomatidae) is described. This new taxon occurs on the ambulacral grooves and wreath of pedicellariae around superomarginal spines of the sea star Sclerasterias euplecta (Fisher) (Asteroidea: Forcipulatida: Asteriidae). Although the family Paradoxostomatidae Brady & Norman, 1889 contains four ectoparasitic or commensal genera, the association with asteroideans has never hitherto been reported. Morphological observations suggested that A. ohtsukai n. g., n. sp. is closely associated with the host sea star as it typically has distal hooks on the antenna and fifth to seventh limbs, and specialised mandibula and maxillula structures that are considered adaptations to a commensal life-style. In addition, this study discussed the feeding habits of A. ohtsukai n. g., n. sp. based on comparison with previous works. The extremely reduced palp and endites of maxillula of A. ohtsukai n. g., n. sp. imply that they have unique feeding habits that are not based on the feeding function of maxillula. From morphological comparisons with siphonostomatoid copepods, we suggest that A. ohtsukai n. g., n. sp. may feed on the body of host sea star by injuring them with styliform needle-like mandibular coxa and sucking the tissues, body fluid, or mucus with the suctorial disc on the oral cone.     

The ontogeny of Loxoconcha japonica Ishizaki, 1968 (Cytheroidea, Ostracoda, Crustacea)

The ontogeny of the cytheroidean species Loxoconcha japonica is documented from the earliest instar to the adult. The first instar (instar A-8) of L. japonica is different from that of cypridoidean species in that it has an additional appendage, the furca, present. From instar A-7 onwards, the appearance of the appendages is similar to that of cypridoidean and bairdioidean species. The furca is well developed in instars A-8 to A-5, and is probably an important appendage in these early instars, despite its reduced form in the adults. Some appendages of L. japonica (e.g. the antennae) gain very few setae and claws through ontogeny, compared with species from other superfamilies. This possibly reflects paedomorphic evolution of this species.     

Invasion biology in non‐free‐living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda,Entocytheridae)

In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement‐related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non‐free‐living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum‐Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum‐Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This approach can also be implemented in other systems where the target species is closely interacting with other taxa.     

Comparison of Two Chemicals for Removing an Entocytherid (Ostracoda: Crustacea) Species from Its Host Crayfish (Cambaridae: Crustacea)

Entocytherids are epifauna on larger crustaceans. We assessed the effectiveness of chlorobutanol and carbonated water for removing entocytherid, Ankylocythere sinuosa, from crayfish, Procambarus clarkii. This was done using different exposure times and by assessing entocytherid and crayfish survival, together with the number of entocytherids removed. According to our results, chlorobutanol submersion of crayfishes in shorter time periods is more effective for removing entocytherids without killing the crayfish host. However, carbonated water submersion is better to extract larger amounts of living entocytherids. Finally, both chemicals are appropriate tools to establish standardised protocols for removing entocytherids from crayfish for ecological studies because the proportions of removed entocytherids per crayfish become constant whatever the entocytherid load of the crayfish. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The ontogeny of two species of Darwinuloidea (Ostracoda, Crustacea)

The ontogeny of two species of the ostracod superfamily Darwinuloidea, Darwinula stevensoni (Brady and Robertson, 1870) and Vestalenula sp., is documented. The development of the appendages of the two species is very similar, with the exception of the antennule, which shows some variation. The general appearance of appendages during ontogeny of the two species is very similar to that of species of other podocopid superfamilies, such as the Cytheroidea, Terrestricytheroidea, Bairdioidea and Cypridoidea, and different from that of the Platycopida. Using the development of the antenna and the appearance of antennal features, a revised model of darwinulid antennal terminology is presented that homologizes these features with those of the Cypridoidea.     

The ontogeny of appendages of Heterocypris salina (Brady, 1868) Ostracoda (Crustacea)

The post-embryonic development of the appendages of the Cyprididae ostracod Heterocypris salina (Brady, 1868) are described in detail and compared with those of other podocope species documented in previous studies. Generally, the appearence of limbs during onotgeny of H. salina is similar to that of other species, but small differences in limb morphologies were identified between H. salina and other Cyprididae species, including other Heterocypris species. Some features appear either earlier or later in the development of H. salina compared with other species, even species of the same genus. These features may be useful characters for phylogenetic analyses at the genus and family levels.     

Heterochronic mechanisms of morphological diversification and evolutionary change in the neotropical salamander,Bolitoglossa occidentalis (Amphibia: Plethodontidae)

Bolitoglossa occidentalis, a lowland salamander of Mexico and Guatemala, has a highly derived morphology. The features that are derived with respect to the condition in generalized members of the genus include the following: (1) small body size; (2) short tail; (3) fully webbed hands and feet; (4) reduction and loss of certain phalangeal elements; (5) fusion of carpals and tarsals; (6) absence of prefrontal bones; and (7) reduced skull ossification. The ontogeny of this species was analyzed quantitatively and compared with the patterns of growth and differentiation encountered in two morphologically generalized members of the genus, B. rostrata and B. subpalmata. Most of the derived features can be explained by invoking a single heterochronic process: truncation of development at a small size (most likely the product of early maturation). Therefore, B. occidentalis is a paedomorphic species whose morphology has been attained through the process of progenesis. This result supports Alberch's ('80a) prediction, based on functional analysis, that the principle adaptation to arboreality in B. occidentalis is small size; other derived morphological features are associated with the organism's truncated development and may have no adaptive significance. However, patterns of dissociation are found within this overall progenetic process. Some of these include the following: (1) accelerated growth rates of the metatarsals and first phalanges, and retarded growth rates of the second and third phalangeal elements; (2) dissociation between rates of ossification of the skull and the autopodial elements; and (3) dissociation between the timing of termination of the process of shape change during the ontogeny of the foot (the product of differential growth between digital and interdigital areas) and termination of growth in overall foot size (foot surface area). This later result illustrates the independence of morphogenetic phenomena (shape change) from processes of growth (size increase).     

Evaluation of a new character for the phylogenetic analysis of Ostracoda (Crustacea): the podocopan maxillular branchial plate

A data set of the number of setae on the maxillular branchial plate of podocopan ostracods was compiled from published drawings and our own dissections. A total of 168 species in six superfamilies were covered, with the Cytheroidea, Cypridoidea and Bairdioidea being best represented. The number of setae is shown to be independent of the size of the ostracod and the environment in which the species lives, but to have phylogenetic significance at superfamily level. Ontogenetic data suggest that the low number of branchial plate setae in many cytheroidean families is a paedomorphic phenomenon.     

Rogerella isp. Infesting the Pore Pairs of Hemipneustes striatoradiatus (Leske) (Echinoidea: Upper Cretaceous,Belgium)

An otherwise well-preserved test of the holasteroid echinoid Hemipneustes striatoradiatus (Leske) from the Emael Member, Maastricht Formation (Maastrichtian, Upper Cretaceous) of Belgium, is infested by encrusting bivalves and foraminiferans and the boring Rogerella isp. In this specimen, Rogerella preferentially infested and modified the ambulacral pore pairs of the echinoid close to the apex. This was not a commensal association. The echinoid test shows no growth deformations in response to this invasion; pore pairs are locally strongly infested; and encrusting invertebrates testify to the long post-mortem residence time of the test on the sea floor. Rather, the pore pairs of the dead echinoid were crannies attractive to settling larvae of acrothoracian barnacles, the producers of Rogerella.     

Ontogeny of head and caudal fin shape of an apex marine predator: The tiger shark (Galeocerdo cuvier)

How morphology changes with size can have profound effects on the life history and ecology of an animal. For apex predators that can impact higher level ecosystem processes, such changes may have consequences for other species. Tiger sharks (Galeocerdo cuvier) are an apex predator in tropical seas, and, as adults, are highly migratory. However, little is known about ontogenetic changes in their body form, especially in relation to two aspects of shape that influence locomotion (caudal fin) and feeding (head shape). We captured digital images of the heads and caudal fins of live tiger sharks from Southern Florida and the Bahamas ranging in body size (hence age), and quantified shape of each using elliptical Fourier analysis. This revealed changes in the shape of the head and caudal fin of tiger sharks across ontogeny. Smaller juvenile tiger sharks show an asymmetrical tail with the dorsal (upper) lobe being substantially larger than the ventral (lower) lobe, and transition to more symmetrical tail in larger adults, although the upper lobe remains relatively larger in adults. The heads of juvenile tiger sharks are more conical, which transition to relatively broader heads over ontogeny. We interpret these changes as a result of two ecological transitions. First, adult tiger sharks can undertake extensive migrations and a more symmetrical tail could be more efficient for swimming longer distances, although we did not test this possibility. Second, adult tiger sharks expand their diet to consume larger and more diverse prey with age (turtles, mammals, and elasmobranchs), which requires substantially greater bite area and force to process. In contrast, juvenile tiger sharks consume smaller prey, such as fishes, crustaceans, and invertebrates. Our data reveal significant morphological shifts in an apex predator, which could have effects for other species that tiger sharks consume and interact with. J. Morphol. 277:556–564, 2016. © 2016 Wiley Periodicals, Inc.     

Light spectra blocking films reduce numbers of western flower thrips,Frankliniella occidentalis (Thysanoptera: Thripidae) in strawberry,Fragaria x ananassa

1. Frankliniella occidentalis is a pest of horticultural crops, including commercial strawberry (Fragaria x ananassa). Control is challenging because certain populations are resistant to insecticides and, in strawberry, now relies on the application of biocontrols. However, this approach is not always successful if F. occidentalis populations overwhelm biocontrols. We investigated whether targeted spectral modifications to cladding materials could reduce numbers of F. occidentalis, in strawberry flowers.
2. Five UV-attenuating plastic-film materials were tested in three, 6-week, semi-field tunnel experiments containing strawberry plants. F. occidentalis were introduced into tunnels from a laboratory culture and subsequent numbers that developed in strawberry flowers were recorded.
3. Limiting UV-A radiation to the crop significantly reduced the numbers of adult and larval F. occidentalis in strawberry flowers. The numbers of adult (and larvae) in flowers were reduced by 42 (47)%, 54 (41)%, 70 (73)%, and 82 (73)% in UV350, UV370, UV400, and UV430-attenuating films, respectively, compared with the UVopen (control) film. However, no damage to strawberry fruits was observed regardless of the film treatment.
4. Incorporating UV-attenuating films as tunnel cladding can suppress F. occidentalis numbers in strawberry. Reducing populations of F. occidentalis in crops is likely to enable the more successful use of other non-chemical control strategies.

     

Effects of foliar apple trichomes on Galendromus occidentalis (Nesbitt) (Acari: Phytoseiidae): preferences,fecundity and prey consumption

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Evolution of antennules of cytheroidean ostracods (Crustacea)

Phylogenetic analysis and fossil records indicate that antennules with whip-like setae are the most plesiomorphic state in cytheroidean ostracods and that antennulae with claw-like setae are derived from antennulae with whip-like setae. Character distributions on the 18S rDNA molecular phylogenetic tree suggest that two phenotypic features of cytheroidean antennules (W/L ratio and claw-like/whip-like setae) have morphological plasticity. These features have evolved as an ethological adaptation rather than due to phylogenetic constraints such as the evolution of shell outline in cytheroideans. However, the species of the Leptocytheridae–Trachyleberididae clade generally have stout, robust antennules, indicating a phylogenetic constraint. The character state of setae (claw/whip) in cytheroidean ostracods is reflected more through their ethology than the W/L ratio of the antennules. On the basis of the present analysis and the fossil record, diversification in the morphology of the antennules seems to have occurred during the early Mesozoic.     

Cranial and mandibular morphology of Middle Pleistocene cave bears (Ursus deningeri): implications for diet and evolution

ABSTRACT

Deninger’s bears (Ursus deningeri) have been studied less frequently than Ursus spelaeus s.l. Our objective is to present, for the first time, an analysis of the skull shape of U. deningeri.

Bear crania and mandibles were digitised with a Microscribe or CT-scanned and the surface models subsequently landmarked. The landmarks were chosen based on a compromise between functional morphology and sample size.

Results show that U. deningeri and U. spelaeus mandibles display very similar morphologies and allometric trajectories, both to each other and to Ailuropoda melanoleuca. It is inferred that masticatory adaptations to a herbivorous diet were already present in the Middle Pleistocene. U. deningeri displays a cranial morphology that is similar to that of U. spelaeus when comparing all species, but U. deningeri has a relatively narrower and dorsoventrally lower zygomatic arch than U. spelaeus, although the masticatory signal is less strong in the skull.

We observe intraspecific differences between different populations of U. deningeri, which could parallel the genetic diversity found in U. spelaeus. The intraspecific differences found within U. deningeri may be temporal and/or geographical in nature and could be related to the evolution of the Late Pleistocene cave bear, but this hypothesis remains to be tested.     

Effect of different diets on reproduction,longevity and predation capacity of Orius insidiosus (Say) (Hemiptera: Anthocoridae)

Orius insidiosus is a generalist predator for which diet influences important biological traits like reproduction and predation. We tested the effects of different diets alone or in combination on reproduction, longevity and predation capacity of this predator. The diets tested were: no food (control); pollen; Frankliniella occidentalis (Pergande) nymphs and adults; F. occidentalis nymphs and adults and pollen; Anagasta kuehniella (Zeller) eggs; A. kuehniella eggs and pollen; A. kuehniella eggs; F. occidentalis nymphs and adults and A. kuehniella eggs, F. occidentalis nymphs and adults and pollen. The pre-oviposition period was shortest when the diet consisted of pollen and prey (A. kuehniella and/or F. occidentalis), of the two prey species together or of only A. kuehniella eggs. The highest values for the length of the oviposition period (50.1, 48.0, 46.3 and 46.1 days), daily fecundity (3.8, 3.9, 4.0 and 4.2 eggs/female/day), total fecundity (190.3, 187.7 185.2 and 193.6 eggs/female) and longevity (52.1, 49.9, 48.7 and 48.0 days) were found with diets consisting of only A. kuehniella eggs. Pollen did not improve any of the performance parameters of the predator when offered exclusively or as a complementary food. The results show that selection of a proper diet can strongly improve reproduction, longevity and predation capacity of O. insidiosus. An important finding is that A. kuehniella eggs, which can easily be produced in large quantities, are an excellent factitious prey for mass production of O. insidiosus.     

Demographic effects of pesticides on biological control of Pacific spider mite (Tetranychus pacificus) by the western predatory mite (Galendromus occidentalis)

The western predatory mite, Galendromus occidentalis (Nesbitt) (Acari: Phytoseiidae), is a predator of Pacific spider mite, Tetranychus pacificus McGregor (Acari: Tetranychidae), in California vineyards. We evaluated the effects of six pesticides on biological control of T. pacificus on grape plant microcosms in a two-way design: presence and absence of G. occidentalis crossed with presence and absence of pesticide. The insecticide imidacloprid did not affect T. pacificus population growth rate, but it led G. occidentalis populations close to extinction. As a result, T. pacificus populations grew significantly higher in microcosms with release of G. occidentalis and treated with imidacloprid than with G. occidentalis alone. The fungicide wettable sulfur significantly decreased T. pacificus population growth rate but it did not affect G. occidentalis. Consequently, T. pacificus populations were significantly lower in microcosms with release of G. occidentalis and treated with wettable sulfur than with G. occidentalis alone. The insecticide buprofezin had no effect on T. pacificus population growth rate. Although buprofezin did not impact the ability of G. occidentalis to suppress T. pacificus, it negatively affected G. occidentalis population growth rate. The fungicides trifloxystrobin and tebuconazole and the insecticide methoxyfenozide had no influence on T. pacificus or G. occidentalis population growth rates. Furthermore, none of the pesticides affected the sex ratio of G. occidentalis, but buprofezin, methoxyfenozide and trifloxystrobin affected its stage structure. Our study demonstrates that simultaneous testing of the demographic effects of pesticides on pests and natural enemies is essential for a full assessment of pesticide impacts on biological control.     

Postnatal ontogenetic scaling of Nesodontine (Notoungulata,Toxodontidae) cranial morphology

Cassini G.H., Flores D.A. and Vizcaíno S.F. 2012. Postnatal ontogenetic scaling of Nesodontine (Notoungulata, Toxodontidae) cranial morphology. —Acta Zoologica (Stockholm) 93 : 249–259. Toxodontidae is a clade of endemic South American ungulates that comprises medium to very large animals, including strict megammamals, i.e., 1000 kg or more. Adinotherium at approximately 120 kg and Nesodon at 550 kg are, respectively, the smallest and the largest Nesodontinae of Santacrucian age (early Miocene). The large number of specimens recorded and the quality of preservation (including very young animals) permit a morphometric study of cranial ontogeny. We measured 17 cranial variables on an ontogenetic series of 23 specimens of Adinotherium ovinum and 11 of Nesodon imbricatus. Bivariate analysis (standardized major axis) was performed to obtain the coefficients of allometry using skull length as the independent variable. Results indicate that eight of 16 variables show an isometric trend, seven exhibit positive allometry, and only the height of the orbit in N. imbricatus exhibits negative allometry. Contrary to expectation, neurocranial variables are positively allometric or isometric. With respect to the splanchnocranium, most variables related to the rostrum, palate, and masticatory muscles show positive allometry, suggesting a strengthening of masticatory system in adults of both taxa. The splanchnocranial allometric trends fail to support previous inferences of specialized herbivory, suggesting generalized herbivory in nesodontines.     

Microbial diversity in the predatory mite Metaseiulus occidentalis (Acari: Phytoseiidae) and its prey, Tetranychus urticae (Acari: Tetranychidae)

Microorganisms associated with the predatory mite Metaseiulus (=Typhlodromus or Galendromus) occidentalis (Nesbitt) and its prey, the two-spotted spider mite Tetranychus urticae (Koch), were assessed using a high-fidelity polymerase chain reaction (PCR) protocol and primers designed to identify Eubacteria, Archaeabacteria, iridoviruses, Helicosporidia, Cytophaga-like microorganisms, Wolbachia and its bacteriophage WO, fungi and yeast-like organisms. Sequences from four bacterial species related to Wolbachia (α-Proteobacteria), Cardinium, Bacteroidetes, and Enterobacter (γ-Proteobacteria) were obtained from M. occidentalis, and three sequences related to Wolbachia, Rickettsia, and Caulobacter (α-Proteobacteria) were obtained from T. urticae. No nucleotide differences were detected between the 16S rRNA, wspA or wspB Wolbachia sequences obtained from M. occidentalis and T. urticae, which suggest that horizontal transfer of Wolbachia could have occurred. Southern blot analyses of genomic DNA from both M. occidentalis and T. urticae using wspA probes were negative, indicating that this Wolbachia sequence is not integrated into the nuclear genome of either species. Two of the T. urticae colonies tested contained the WO bacteriophage, but none of the six M. occidentalis populations were infected. New M. occidentalis-specific forward and reverse 16S rRNA primers based on the Wolbachia, Cardinium, Bacteroidetes, and Enterobacter sequences obtained were designed and used to amplify PCR products from each of two laboratory and four field-collected samples of M. occidentalis females and eggs, indicating that these infections are widespread. Likewise, species-specific primers for T. urticae were designed for the Wolbachia, Rickettsia, and Caulobacter sequences obtained and used to evaluate T. urticae from strawberries, wine grapes, hops, almonds, and cherries from California, Washington, and Florida; all were positive for Wolbachia and Caulobacter but two of the six were negative for Rickettsia. None of the M. occidentalis colonies tested were positive for the microsporidium Oligosporidium occidentalis, which previously had been associated with a pathogenic condition in some of our laboratory colonies. The Gainesville colonies of M. occidentalis and T. urticae were negative for iridovirus, Archaeabacteria, fungi, Helicosporidia, and yeast-like organisms. So far, Wolbachia is the only symbiont that is shared by this predator and its prey.