Visual stimuli that elicit visual tracking, approaching and striking behavior from an unusual praying mantis, Euchomenella macrops (Insecta: Mantodea)

In comparison to other similarly sized mantis species examined in previous studies, Euchomenella macrops has a significantly smaller head, shorter foreleg tibia, but longer prothorax which have been interpreted as specializations for the capture of smaller, slower prey. We tested this conjecture by assessing the rates at which computer generated stimuli elicit visual tracking, approaching, and striking behaviors by adult females. When presented with black disks moving erratically against a white background, strike rate rose progressively as disks enlarged up to 44 deg (visual angle) if the disks moved rapidly (e.g., 143 deg/s); at slower speeds (113, 127 deg/s), smaller disks (<27 deg) were preferred. When black moved linearly from the visual periphery to visual field center (at 73 or 143 deg/s) and then stopped, E. macrops struck consistently at disks as small as 5 deg after movement ceased. E. macrops also struck at higher rates in response to 23 deg erratically moving (subjective) red (versus subjective blue or green) disks that were luminance matched to a grey background although they tracked all colors at equally high rates. Unlike some other species, E. macrops did not strike at higher rates in response to elongated rectangular stimuli moving parallel (versus perpendicular) to their long axis, although the former elicited higher rates of approaching. An analysis of tracking behavior revealed that virtually all tracking movements were a result of head (versus) prothorax rotation.     

Appetitive Responses to Computer-Generated Visual Stimuli by Female Rhombodera basalis, Deroplatys lobata, Hierodula membranacea, and Miomantis sp. (Insecta: Mantodea)

We used computer-generated stimuli to assess the stimulus parameters eliciting prey-directed behaviors in four mantis species: Rhombodera basalis (60 mm body length), Deroplatys lobata (70 mm), Hierodula membranacea (80 mm), Miomantis sp (38 mm). All responded appetitively to erratically moving disks subtending 10° or more. R. basalis responded more consistently to checkered (versus solid black) disks; only D. lobata displayed a size preference (14–23 deg disks); Miomantis sp. struck at disks as large as did the largest species; only Miomantis sp. displayed approaching behavior. H. membranacea and R. basalis preferred black disks on a white background (versus the reverse), and red disks (versus blue or green) on a brightness-matched grey background. All preferred elongated stimuli moving parallel (versus perpendicular) to their long axes.     

Growth and fecundity of fertile Miscanthus × giganteus (“PowerCane”) compared to feral and ornamental Miscanthus sinensis in a common garden experiment: Implications for invasion

Perennial grasses are promising candidates for bioenergy crops, but species that can escape cultivation and establish self‐sustaining naturalized populations (feral) may have the potential to become invasive. Fertile Miscanthus × giganteus, known as “PowerCane,” is a new potential biofuel crop. Its parent species are ornamental, non‐native Miscanthus species that establish feral populations and are sometimes invasive in the USA. As a first step toward assessing the potential for “PowerCane” to become invasive, we documented its growth and fecundity relative to one of its parent species (Miscanthus sinensis) in competition with native and invasive grasses in common garden experiments located in Columbus, Ohio and Ames, Iowa, within the targeted range of biofuel cultivation. We conducted a 2‐year experiment to compare growth and reproduction among three Miscanthus biotypes—”PowerCane,” ornamental M. sinensis, and feral M. sinensis—at two locations. Single Miscanthus plants were subjected to competition with a native grass (Panicum virgatum), a weedy grass (Bromus inermis), or no competition. Response variables were aboveground biomass, number of shoots, basal area, and seed set. In Iowa, all Miscanthus plants died after the first winter, which was unusually cold, so no further results are reported from the Iowa site. In Ohio, we found significant differences among biotypes in growth and fecundity, as well as significant effects of competition. Interactions between these treatments were not significant. “PowerCane” performed as well or better than ornamental or feral M. sinensis in vegetative traits, but had much lower seed production, perhaps due to pollen limitation. In general, ornamental M. sinensis performed somewhat better than feral M. sinensis. Our findings suggest that feral populations of “PowerCane” could become established adjacent to biofuel production areas. Fertile Miscanthus × giganteus should be studied further to assess its potential to spread via seed production in large, sexually compatible populations.     

Differential expression of genes involved in alternative glycolytic pathways,phosphorus scavenging and recycling in response to aluminum and phosphorus interactions in <Emphasis Type="Italic">Citrus</Emphasis> roots

The objective was to determine the possible links between the expression levels of genes involved in alternative glycolytic pathways, phosphorus (P) scavenging and recycling and Citrus tolerance to aluminum (Al) and/or P-deficiency. ‘Xuegan’ (Citrus sinensis) and ‘Sour pummelo’ (Citrus grandis) seedlings were irrigated for 18 weeks with nutrient solution containing 0 and 1.2 mM AlCl₃·6H₂O × 0, 50 and 200 μM KH₂PO₄. C. sinensis displayed more tolerant to Al and P-deficiency than C. grandis. Under Al stress, C. sinensis accumulated more Al in roots and less Al in shoots than C. grandis. P concentration was higher in C. sinensis shoots and roots than in C. grandis ones. C. sinensis roots secreted more malate and citrate than C. grandis ones when exposed to Al. Al-induced-secretion of malate and citrate by excised roots from Al-treated seedlings decreased with increasing P supply. Al-induced-secretion of malate and citrate from roots and Al precipitation by P in roots might be responsible for Al-tolerance of C. sinensis. qRT-PCR analysis showed that Al-activated malate transporter (ALMT1), ATP-dependent phosphofructokinase (ATP-PFK), pyrophosphate-dependent phosphofructokinase (PPi-PFK), tonoplast adenosine-triphosphatase subunit A (V-ATPase A), tonoplast pyrophosphatase (V-PPiase), pyruvate kinase (PK), acid phosphatase (APase), phosphoenolpyruvate carboxylase (PEPC), malic enzyme (ME) and malate dehydrogenase (MDH) genes might contribute to the tolerance of Citrus to Al and/or P-deficiency, but any single gene could not explain the differences between the two species. Citrus tolerance to Al and/or P-deficiency might be caused by the coordinated regulation of gene expression involved in alternative glycolytic pathways, P scavenging and recycling.     

Defence behaviours of the praying mantis Tenodera aridifolia in response to looming objects

Defence responses to approaching objects were observed in the mantis Tenodera aridifolia. The mantis showed three kinds of behaviour, fixation, evasion and cryptic reaction. The cryptic reaction consisted of rapid retraction of the forelegs under the prothorax or rapid extending of the forelegs in the forward direction. Obstructing the mantis’ sight decreased its response rates, suggesting that the visual stimuli generated by an approaching object elicited the cryptic reaction. The response rate of the cryptic reactions was highest for objects that approached on a direct collision course. Deviation in a horizontal direction from the direct collision course resulted in a reduced response. The response rate of the cryptic reaction increased as the approaching velocity of the object increased, and the rate decreased as the object ceased its approach at a greater distance from the mantis. These results suggest that the function of the observed cryptic reactions is defence against impending collisions. The possible role of the looming-sensitive neuron in the cryptic reaction is also discussed.     

Responses of descending neurons to looming stimuli in the praying mantis <Emphasis Type="Italic">Tenodera aridifolia</Emphasis>

Responses to visual stimuli of some neurons that descend the nerve cord from the brain were recorded extracellularly in the mantis Tenodera aridifolia. Most of the recorded neurons showed their largest responses to looming stimuli that simulated a black circle approaching towards the mantis. The neurons showed a transient excitatory response to a gradually darkening or receding circle. The neurons showed sustained excitation to the linearly expanding stimuli, but the spike frequency decreased rapidly. The responses of the neurons were affected by both the diameter and the speed of looming stimuli. Faster or smaller looming stimuli elicited a higher peak frequency. These responses were observed in both recordings from the connective between suboesophageal and prothoracic ganglia and the connective between prothoracic and mesothoracic ganglia. There was a one-to-one correspondence of spike firing between these two recordings with a fixed delay. The neurons had the receptive field on ipsilateral side to its axon at the cervical connective. These results suggest that there is a looming-sensitive descending neuron, with an axon projecting over prothoracic ganglion, in the mantis nervous system.     

Biomass yield in a genetically diverse Miscanthus sinensis germplasm panel evaluated at five locations revealed individuals with exceptional potential

To breed improved biomass cultivars of Miscanthus ×giganteus, it will be necessary to select the highest‐yielding and best‐adapted genotypes of its parental species, Miscanthus sinensis and Miscanthus sacchariflorus. We phenotyped a diverse clonally propagated panel of 569 M. sinensis and nine natural diploid M. ×giganteus at one subtropical (Zhuji, China) and five temperate locations (Sapporo, Japan; Leamington, Ontario, Canada; Fort Collins, CO; Urbana, IL; and Chuncheon, Korea) for dry biomass yield and 14 yield‐component traits, in trials grown for 3 years. Notably, dry biomass yield of four Miscanthus accessions exceeded 80 Mg/ha in Zhuji, China, approaching the highest observed for any land plant. Additionally, six M. sinensis in Sapporo, Japan and one in Leamington, Canada also yielded more than the triploid M. ×giganteus ‘1993‐1780’ control, with values exceeding 20 Mg/ha. Diploid M. ×giganteus was the best‐yielding group at the northern sites. Genotype‐by‐environment interactions were modest among the five northern trial sites but large between Zhuji, and the northern sites. M. sinensis accessions typically yielded best at trial sites with latitudes similar to collection sites, although broad adaptation was observed for accessions from southern Japan. Genotypic heritabilities for third year yields ranged from 0.71 to 0.88 within locations. Compressed circumference was the best predictor of yield. These results establish a baseline of data for initiating selection to improve biomass yield of M. sinensis and M. ×giganteus in a diverse set of relevant geographies.     

Community effects of praying mantids: a meta-analysis of the influences of species identity and experimental design

Abstract 1. Generalist arthropod predators are ubiquitous in terrestrial ecosystems but experimental studies have yielded little agreement as to their effects on prey assemblages. Drawing on results from a suite of experimental field studies, a meta‐analysis was conducted of the impact of praying mantids (Mantodea: Mantidae) on arthropod assemblages in order to identify predictable and unpredictable effects of these extremely generalised predators. 2. Results across different experiments were synthesised using the log response ratio framework, with a focus on quantifying net mantid impacts on arthropod density across taxonomic orders and trophic levels of arthropods, paying special attention to the contribution of mantid species identity and experimental design variables, such as the use of cages, length of experiment, and manipulated mantid density. 3. Calculated on a per mantid‐day basis, the net impacts of Tenodera sinensis on arthropod density were generally weaker but more predictable than the effects of Mantis religiosa. Mantids in general had weak negative effects on density for most taxa but exhibited strong negative and positive effects on some taxa. Tenodera sinensis tended to have negative effects on Homoptera, Diptera, and Hemiptera and herbivores as a group, however M. religiosa exhibited greater variation in response of different taxa that appeared to be affected more strongly by experimental design. The effects of Stagmomantis carolina tended to be negative or non‐significant. 4. Experimental cages had little influence on either the sign or magnitude of net community impacts for T. sinensis, however cage experiments reversed the sign of the mean effect for two of six taxonomic orders when the experimental predator was M. religiosa. Cages also increased the variability of effect size greatly for M. religiosa but not for T. sinensis. 5. It was concluded that it is possible to use log response ratios to determine general, predictable trends in a well‐studied system. Similar meta‐analyses of generalist predator effects in other systems should produce predictions of how these predators influence food webs, an important step towards defining more clearly the influences of generalist predators on community structure and dynamics.     

How Far Stationary Contrast Boundaries Can Be Away to Elicit Behavioral Responses in Praying Mantis

The aim of the present study was to investigate the distance at which vertical black and white stripes (contrast boundaries) elicit object-related behavioral responses in 6th instar and adults of the praying mantis Mantis religiosa. The mantids reacted when the contrast boundaries were not further away than 60 cm. However, with increasing distance (>20 cm), the contrast boundaries became progressively less significant for the mantids. Jumps/preparation of jumps could be observed between 10 and 30 cm. The results are supportive for distance measurement of up to 20–30 cm, which corresponds to distance accessible for the insect. It seems that image motion cues induced by peering movements play an important role.     

Effects of several establishment modes of Miscanthus × giganteus and Miscanthus sinensis on yields and yield trends

Miscanthus is a C4 perennial grass originating from East Asia, the yields of which progressively increase in the first years of growth. Several species for bioenergy have been studied since the mid‐1980s in Europe, in particular (Miscanthus × giganteus [M. × giganteus]), due to its high yields. M. × giganteus is mainly cultivated in France and established from rhizomes. Our study aimed to assess, in field conditions, alternative establishment methods combined with an alternative species, Miscanthus sinensis (M. sinensis). We set up a multi‐environment experimental network. On each trial, we tested two treatments with M. × giganteus, established from rhizomes (G_r‐sd) and from plantlets obtained from rhizomes (G_p‐sd), and two treatments with M. sinensis seedlings transplanted in single (S_p‐sd) and double density (S_p‐dd). ANOVA was performed to compare establishment and regrowth rates across treatments, as well as yields across treatments and site‐years. A logistic model was used to describe yield trends and to compare the maximum yield reached and the rate of yield increase of both species. Results showed that miscanthus establishment from plantlets resulted in higher establishment (between 87% and 92%) and regrowth (between 91% and 94%) rates compared to establishment from rhizomes. Treatments with M. × giganteus obtained higher average yields across site‐years than those with M. sinensis, but more variable yields across site‐years. We showed a strong species effect on yields, yield components (shoot weight, shoot density and shoot number per plant) and light interception (through leaf area index). Lastly, to use M. sinensis established from transplanted plantlets as an alternative to M. × giganteus, research would be required on the breeding of M. sinensis sterile seeds to avoid risks of invasiveness.     

Sexual Approach in the Praying Mantid Mantis Religiosa (L.)

Males of sexually cannibalistic species are thought to express behaviors that reduce the risk of being killed by the females. In several spider species the male modulates his approach to the female as a function of her feeding behavior. We tested this hypothesis in the preying mantid Mantis religiosa (L.). Males were placed behind perching females in a laboratory arena and their position was video-recorded. Females were presented with a prey item (prey-presentation period) and then either they were allowed to capture and eat the prey (“P” treatment), or the prey was removed before the female could capture it (“NP” treatment). For the next 10 min (between-prey-presentation period) the females ate the prey (P), or perched without moving (NP). Total speed of approach of males was over 6-times higher in the P treatment (2.3 cm/min) than in the NP treatment (0.4 cm/min). Speed in the prey-presentation period was higher in P than in NP (4.4 cm/min and 1.3 cm/min, respectively), which shows that seeing a female striking and/or grasping the prey in itself stimulated faster male approach. Approach speed in the between-prey presentation period was also higher in P than in NP (1.9 cm/min and 0.2 cm/min, respectively), which indicates that seeing a female feeding on the prey and/or cleaning her forelegs also stimulates male approach. We conclude that males of M. religiosa can assess the activity state of the females and respond to this information by modulating their speed of approach, probably reducing the risk of being detected and possibly cannibalized.     

Winter hardiness of Miscanthus (II): Genetic mapping for overwintering ability and adaptation traits in three interconnected Miscanthus populations

Miscanthus × giganteus (M×g) is the primary species of Miscanthus for bioenergy feedstock production. The current leading biomass cultivar, M×g ‘1993‐1780’, is insufficiently adapted in temperate regions with cold winters such as USDA hardiness zone 5 (average annual minimum temperature of ?28.9 to ?23.3°C) or lower. Three interconnected Miscanthus F₁ populations that shared a common parent were planted in a replicated field trial at Urbana, IL (hardiness zone 5b; average annual minimum temperature of ?26.1 to ?23.3°C) in spring 2011. The winter of 2013–2014 was especially cold in Urbana, with a minimum soil temperature at 10 cm of ?6.2°C and a minimum air temperature of ?25.3°C, giving us an opportunity to evaluate hardiness on established year‐3 plants. The parent in common to all three populations, M. sinensis ssp. condensatus ‘Cosmopolitan’, is native to maritime southern Japan, and in Urbana, it is winter‐damaged most years. In contrast, the three other parents, M. sacchariflorus ‘Robustus’ (MapA), M. sinensis ‘Silberturm’ (MapB), and M. sinensis ‘November Sunset’ (MapC), are typically winter hardy in Urbana. Nearly all MapA progeny plants survived and grew vigorously in spring 2014, whereas in MapB and MapC, many progeny plants did not survive the winter, and most of the survivors were severely damaged, with poor vigor. Negative correlations between overwintering ability and spring regrowth date and autumn dormancy date suggested that the genotypes most likely to survive winters were those that emerged early in spring and/or went dormant early in autumn. Using joint‐population analysis, we identified 53 quantitative trait loci (QTLs) for nine adaptation traits, including nine QTLs for overwintering ability and 11 for spring hardiness scores. Many biologically intuitive candidate genes were observed within or near the QTLs detected in this study, suggesting their validity and potential for further study.     

Genome-wide exploration reveals distinctive northern and southern variants of Clonorchis sinensis in the Far East

Clonorchis sinensis is a carcinogenic liver fluke that causes clonorchiasis—a neglected tropical disease (NTD) affecting ~35 million people worldwide. No vaccine is available, and chemotherapy relies on one anthelmintic, praziquantel. This parasite has a complex life history and is known to infect a range of species of intermediate (freshwater snails and fish) and definitive (piscivorous) hosts. Despite this biological complexity and the impact of this biocarcinogenic pathogen, there has been no previous study of molecular variation in this parasite on a genome-wide scale. Here, we conducted the first extensive nuclear genomic exploration of C. sinensis individuals (n = 152) representing five distinct populations from mainland China, and one from Far East Russia, and revealed marked genetic variation within this species between “northern” and “southern” geographical regions. The discovery of this variation indicates the existence of biologically distinct variants within C. sinensis, which may have distinct epidemiology, pathogenicity and/or chemotherapic responsiveness. The detection of high heterozygosity within C. sinensis specimens suggests that this parasite has developed mechanisms to readily adapt to changing environments and/or host species during its life history/evolution. From an applied perspective, the identification of invariable genes could assist in finding new intervention targets in this parasite, given the major clinical relevance of clonorchiasis. From a technical perspective, the genomic-informatic workflow established herein will be readily applicable to a wide range of other parasites that cause NTDs.     

Combined Effects of Food Concentration and Temperature on Competition Among Four Species of <Emphasis Type="Italic">Brachionus </Emphasis>(Rotifera)

We evaluated the effect of algal food density (1.5 × 10⁶, 3.0 × 10⁶ and 4.5 × 10⁶ cells ml⁻¹ of Chlorella) and temperature (22° and 28 °C) on competition among the rotifers Brachionus calyciflorus, Brachionus havanaensis, Brachionus patulus and Brachionus rubens, based on population growth experiments for 24 days. The growth experiments were conducted seperately for each individual rotifer species (i.e., controls), and in mixtures of all four species in equal initial proportions (i.e., under competition). The population growth of B. calyciflorus, B. havanaensis, B. patulus and B. rubens grown separately at two temperatures and at three algal food densities showed typical patterns of lag, exponential and retardation phases in the controls. This pattern differed considerably under competition. In general, we observed that in all of the test species, the highest growth rates were observed at higher food levels and in the absence of congenerics. At 22 °C, under the lowest food level, the differences in the population abundances of B. havanaensis, B. patulus and B. rubens grown alone and in the presence of competition were large. However, these differences reduced as food density was increased from 0.5 × 10⁶ to 4.5 × 10⁶ cells ml⁻¹. At 28 °C and at the lowest food level, all of the other rotifer species eliminated B. havanaensis in mixed cultures. Each brachionid species had a higher rate when grown alone than when cultured with other species. The highest r (mean ± standard error: 0.54 ± 0.01 day⁻¹) was recorded for B. havanaensis at 28 °C under 4.5 × 10⁶ cells ml⁻¹ of algal food density. At 28 °C at low algal food density, the presence of competitors resulted in negative population growth rates for three of the four rotifer species tested.     

Differences in learning between wild and laboratory Ceratitis capitata flies

Laboratory-reared and wild-collected adult female Mediterranean fruit flies, Ceratitis capitata Wiedemann, were exposed to two host fruit species, sweet orange (Citrus sinensis L.) and mock orange (Murraya paniculata Jack: Rutaceae). The effect of experience with a fruit species on acceptance of these fruit species (i.e., learning) differed between lab and wild females, but only for flies that were exposed to mock orange. Similar differences in fruit acceptance between lab and wild females were observed when individuals experienced with one fruit species were exposed to the other fruit species (i.e., switching). Finally, when each group was exposed to sweet orange, wild flies subsequently deprived of host fruit retained the effect of exposure on acceptance of mock orange 1 day longer than did lab flies subsequently deprived of host fruit. An hypothesis is presented by which selection under artificial culture gave rise to these differences.

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Résumé Des Ceratitis capitata femelles, élevées au laboratoire ou obtenues dans la nature à partir d'Eriobotrya japonica, ont été mises en présence de Citrus sinensis et de Murraya paniculata. L'effet de l'accoutumance à une espèce de fruit sur l'acceptation ultérieure des fruits d'une espèce déterminée (c'est-à-dire l'apprentissage) n'était pas le même pour les mouches sauvages et pour les mouches de laboratoire accoutumées à M. paniculata. Les mouches sauvages accoutumées à M. paniculata tentent de pondre dans C. sinensis beaucoup moins fréquemment que dans M. paniculata. Par contre, les mouches de laboratoire accoutumées à M. paniculata tentent de pondre dans M. paniculata aussi souvent que dans C. sinensis. Des différences du même type entre mouches sauvages et mouches du laboratoire ont été observées quand les individus mis en expérience avec une espèce de fruit ont été ensuite exposés à l'autre espèce, c'est-à-dire lors de réapprentissage. L'acceptation finale par les mouches de laboratoire dépend un peu plus de l'exposition à C. sinensis et un peu moins à celle de M. paniculata que lors de l'acceptation finale par des mouches sauvages. Enfin, des mouches sauvages accoutumées à C. sinensis et privées de leurs fruits, conservent un jour de plus l'effet de l'accoutumance, lors de l'acceptation de M. paniculata, que les mouches de laboratoire placées dans les mêmes conditions.Nous émettons l'hypothèse qu'une sélection due aux conditions d'élevage est à l'origine de ces différences. L'élevage dans de grandes bouteilles de polyéthylène peut sélectionner des mouches qui apprennent plus difficilement en présence de petits fruits comme M. paniculata et qui conservent l'influence de l'expérience pendant un temps plus bref.

     

The subdominant status of Echinocereus viridiflorus and Mammillaria vivipara in the shortgrass prairie: The role of temperature and water effects on gas exchange

Summary The subdominant CAM species, Echinocereus viridiflorus and Mammillaria vivipara, collected from the shortgrass prairie in northeastern Colorado were pretreated and analyzed for gas exchange under cool temperatures (20/15°C) and warm temperatures (35/15°C). Well watered plants of both species under a 35/15°C thermoperiod fixed atmospheric CO₂ during the night and early moring. Echinocereus viridiflorus grown and analyzed at 20/15°C fixed CO₂ during the night, early morning and late afternoon but total carbon gain over a 24 h period is less than when grown and analyzed under the 35/15°C thermoperiod. Mammillaria vivipara grown and analyzed at 20/15°C assimilates CO₂ at low rates during all parts of a 24 h period with the greatest CO₂ fixation rates occuring from midday to late afternoon. The total carbon gain under the 20/15°C thermoperiod is less than that for this species under the 35/15°C thermoperiod. Decreasing the night temperature of plants grown under the warm conditions to 10°C or 5°C results in a depression of the night CO₂ fixation in both species. E. viridiflorus from the cool growth conditions showed an enhancement of the CO₂ uptake during the night, early morning and late afternoon when subjected to the cooler night temperatures (10°C and 5°C). The CO₂ uptake of M. vivipara grown at 20/15°C shows an enhancement during the night and early morning while the CO₂ fixation during midday and late afternoon is slightly depressed under cool night temperatures (10° and 5°C). Under the 35/15°C thermoperiod both species exhibit depressed rates of CO₂ fixation during the night and early morning when water stressed. Plants of both species grown under the 20/15°C thermoperiod exhibit no net CO₂ fixation following five weeks of water deprivation. Upon rewatering, E. viridiflorus begins to recover its capacity for CO₂ fixation within 24 h under both the warm and cool temperature regimes. However, M. vivipara did not show recovery within 48 h following rewatering under the warm or cool temperature regime. Contrasting the patterns of gas exchange of the subdominant species, E. viridiflorus and M. vivipara, with a dominant CAM species of the shortgrass prairie, Opuntia polyacantha reveals significant differences that may well dictate the role of these species in this ecosystem. E. viridiflorus and M. vivipara have a lower capacity of carbon gain and recovery from water stress than O. polyacantha mainly due to their lack of late afternoon CO₂ uptake. This study suggests that carbon gain plays an important role in limiting E. viridiflorus and M. vivipara in the shortgrass prairie ecosystem.     

‘Collar propagation’ as an alternative propagation method for rhizomatous miscanthus

The demand for perennial nonfood crops, such as miscanthus, is increasing steadily, as fossil resources are replaced by biomass. However, as the establishment of miscanthus is very expensive, its cultivation area in Europe is still small. The most common propagation method for miscanthus is via rhizomes, the harvesting of which is very labour‐intensive. Seed propagation is promising, but not suitable for sterile genotypes. In this study, a new vegetative propagation method, ‘collar propagation’, was tested in field and controlled environment studies. Collars are built at the junction between rhizome and stem. They can be harvested in a less destructive way than rhizomes by pulling out the stems from winter‐dormant miscanthus plants. One genotype of each of the species M. sacchariflorus, M. × giganteus, M. sinensis in combination with three fragment types (collars, rhizomes, collars + rhizomes) were tested for establishment success and plant performance. The performance (e.g. dry matter yield) of collar‐propagated plants was either better than or not significantly different from rhizome‐propagated plants. Pregrown plantlets transplanted into the field showed no significant differences in establishment success between the fragments within a genotype. When directly planted into the field however, the fragment ‘rhizome+collar’ had a significantly better establishment success than the other two. The winter survival rate of the fragment ‘rhizome+collar’ was 70% for M. sacchariflorus and 75% for M. × giganteus. Emergence success from collar‐derived plants was not affected by harvest date (harvested monthly from November to February). This study showed that miscanthus propagation via collars is feasible and a promising alternative to rhizome propagation, as the multiplication rate of collars is comparable to that of rhizome propagation. Collar propagation is the more suitable method for the tested genotypes of the species M. sachariflorus and M. × giganteus, but not for M. sinensis genotypes, which may be better propagated by seeds.     

The midline metathoracic ear of the praying mantis,Mantis religiosa

Summary The praying mantis, Mantis religiosa, is unique in possessing a single, tympanal auditory organ located in the ventral midline of its body between the metathoracic coxae. The ear is in a deep groove and consists of two tympana facing each other and backed by large air sacs. Neural transduction takes place in a structure at the anterior end of the groove. This tympanal organ contains 32 chordotonal sensilla organized into three groups, two of which are 180° out of line with the one attaching directly to the tympanum. Innervation is provided by Nerve root 7 from the metathoracic ganglion. Cobalt backfills show that the auditory neuropile is a series of finger-like projections terminating ipsilaterally near the midline, primarily near DC III and SMC. The auditory neuropile thus differs from the pattern common to all other insects previously studied.     

A preliminary note on a new optomotor response in crickets: Antennal tracking of moving targets

Summary Black disks moving horizontally in the visual field of a cricket (Gryllus campestris) induce an antennal tracking response. It consists of movements of the ipsilateral antenna following the target in a saccade-like fashion.This work was supported by a grant from the Deutsche Forschungsgemeinschaft Ho 463/12.