Mitopus Morio Research Articles

Epigeic harvestmen (Arachnida: Opiliones) of reforested Norway spruce forest stands in Slovakia: A case study

We evaluated the effect of different ecological factors on epigeic harvestmen (Opiliones) in stands of Norway spruce of different ages planted on former agricultural land in the Western Carpathians (Slovakia). In total, 15 species of harvestmen were recorded, which is 42.9% of the 35 species of harvestmen currently recorded in Slovakia. The most abundant species were Nelima sempronii, Lacinius ephippiatus, Mitopus morio, Oligolophus tridens, Leiobunum gracile and Platybunus bucephalus. Species richness and diversity was not associated with any forest characteristic. There was a negative association between the percentage of Norway spruce and abundance of harvestmen and positive association between the chemical element Ca2+ and harvestmen abundance. Beta diversity of harvestmen assemblages was low. Composition of harvestmen assemblages was significantly related to percentage of spruce, humus content, Ca2+, C/N and soil pH. Lacinius ephippiatus was most abundant in pitfall traps with a low percentage of spruce, Oligolophus tridens plots where there was low humus content and Leiobunum gracile tended to be more abundant in plots with more alkaline soils.

Macronutrient niches and field limitation in a woodland assemblage of harvestmen.

Description of animals' trophic niches helps us understand interactions between species in biological communities that are not easily observed. Analyses of macronutrient niches, that is, the range of macronutrient (protein:lipid:carbohydrate) ratios selected by generalist feeders, may be a useful alternative approach to inter-species comparisons of diets, especially within taxonomic assemblages of predators where species with similar nutritional requirements are likely to accept similar types of prey. Here we analysed the macronutritional niches of a woodland assemblage of seven harvestman species, all supposed to be predators with omnivorous tendencies. Five species (Mitopus morio, Leiobunum gracile, Oligolophus tridens, O. hanseni and Paroligolophus agrestis) were native and two species (Opilio canestrinii and Dicranopalpus ramosus) were recent invaders into the community. We compare the fundamental (FMN) and realized (RMN) macronutritional niche positions of the species using a 'double-test procedure', which provides information on whether the species were food limited in their natural habitat, and whether they were limited by specific macronutrients. All seven species were food limited and six species were non-protein limited in the field; of these, four species were carbohydrate limited, and in one species females were lipid limited and males were carbohydrate limited. These findings add to the notion that predators are mainly non-protein limited in the field. The FMN positions of the assemblage fell within 46%-50% protein, 29%-38% lipid and 16%-22% carbohydrate. The amount of carbohydrate in the self-selected diet combined with carbohydrate limitation confirms that the species are zoophytophagous. Two morphological clusters of species (large long-legged vs. small short-legged species) differed not only in microhabitat (upper vs. lower forest strata) but also in macronutrient selection, where large long-legged species selected higher proportion of carbohydrate than small short-legged species. Thus, morphologically similar species occupy the same habitat stratum and have similar macronutritional niches. We discuss the hypothesis that the invasive O. canestrinii might have an impact on native species as it allegedly had in urban environments previously. Two basic assumptions about interspecific resource competition were fulfilled, that is, high overlap of nutritional requirements and limitation by food and macronutrients.

Early summer aspect of the population of ground–dwelling spiders (aranei), harvestmen (opiliones) and ground beetles (coleoptera, carabidae) in pinus sibirica forests of Shorsky national park

The early summer structure of the communities of ground-dwelling spiders, harvestmen and carabids in Pinus sibirica forests of the Shorsky National Park has been studied for five years. The community was found to consist of 39 spider, 5 harvestman and 12 carabid species. Among spiders,small-sized litter-dwelling web-producing spiders (Linyphiidae) predominated, accounting for over 70 % of collected specimens. The community of wolfspiders (Lycosidae) was small and taxonomically poor, their dynamic density in the study area being rather low and unstable. Although spider species outnumbered the other studied groups, their population was generally scant and unstable. The composition of spider dominants varied among years, their dynamic densities and shares were unstable even in regularly collected species. Pairwise comparisons of the early summer structure of spider communities in different years did not always show statistically significant differences. Early summer communities of harvestmen in Pinus sibirica forests were predominated by juveniles of Mitopus morio (Fabricius, 1779), with first emergences of newly hatched Oligolophus tridens nymphs (C. L. Koch, 1836). The most abundant among eurychronic species was Sabacon sergeidedicatum Martens, 1989. In the early summer beetle community, the family Carabidae was the dominant group of ground-dwelling arthropods. The dominants complex was stable, and included Carabus aeruginosus Fischer von Waldheim, 1822, Pterostichus monticoloides Shilenkov, 1995, P. oblongopunctatus (Fabricius, 1787), and P. virescens (Gebler, 1833). Their population structure did not vary significantly among years. The Sorensen similarity indexes for the species composition of carabid communities in among-year pairwise comparisons were oftener higher than those for spiders.

Ups and Downs among Danish Urban Harvestmen

The opilionid fauna of Northern Europe, including Denmark, has become enriched by range expansion of several species originating from southern Europe, and this process is expected to continue into the future. I present data that describe the changing occurrence (relative abundance, locality representation) of invasive as well as native harvestman species from the urban habitat in Denmark during the 30 year period 1987 to 2017. Three invasive species and three native species have increased both in relative abundance and in the proportion of towns from which they occurred during standardized searches. Another three species showed consistently decreasing trends. Of these, Leiobunum gracile decreased dramatically from being one of the most dominant species to near extinction. Opilio parietinus and Mitopus morio were consistently but less seriously reduced. The abundance of species in the standardized searches varied idiosyncratically in relation to geography (latitude, longitude) and season. Harvestman numbers were negatively correlated with town size (number of inhabitants).

No regulatory role for adult predation in cyclic population dynamics of the autumnal moth,Epirrita autumnata

1. Multiannual population cycles of geometrid moths are thought to be driven by trophic-level interactions involving a delayed density-dependent component. Predation on adult moths has been a little-studied mechanism of this phenomenon. 2. Using 29 daytime and 61 night-time predation trials in the field, we exposed living autumnal moth (Epirrita autumnata Borkhausen, Lepidoptera: Geometridae) females to their natural predators during each autumn throughout the 10-year population cycle. 3. In our northern study location (70°N), insectivorous passerines had already migrated, and harvestman Mitopus morio Fabricius (Opiliones: Phalangiidae) was found to be the main predator of the adult moths. The predation mortality occurred mainly at night and was positively correlated with the minimum temperature measured during the predation trial. 4. Despite high annual variability in the degree of adult predation, both direct and delayed density-dependent effects were weak and indicate that predation on adult moths in the autumn does not have any regulatory role in cyclic population dynamics of the autumnal moth in northern Fennoscandia.

New Canadian records of Nemastoma bimaculatum (Fabricius), and a brief summary of introduced Eurasian harvestmen in North America(Arachnida, Opiliones).

Eurasian harvestmen have been introduced to, and have established themselves in North America. Species known to have been introduced include Trogulus tricarinatus (L.) 1767, Paroligolophus agrestis (Meade) 1855, Rilaena triangularis (Herbst) 1799, Oligolophus tridens (C. L. Koch) 1836, and Nemastoma bimaculatum (Fabricius) 1775, for the last of which new Canadian records (Ontario) are given below. It is not entirely determined if the species Phalangium opilio (L.) 1758, Opilio parietinus (DeGeer) 1778 and Mitopus morio (Fabricius) 1779 are introduced to North America, or are naturally of Holarctic distribution. The former seems the more likely hypothesis for the first two, but M. morio in North America may be native or may not be that species. Detailed descriptions and illustrations of all these species may be found in Martens (1978).

New biogeographical records of spiders and harvestmen (Arachnida: Araneae & Opiliones) from West Siberia, including an annotated list of species

Fifty-three species of spiders and one species of harvestmen were found in the previously unstudied Gydansky Peninsula, northwestern Siberia. Distribution for each species is given. Records of certain species are of a special interest: Xysticus viduus (the northernmost locality in its range), Crosbylonia borealis (the westernmost), Oreoneta eskovi (the northernmost and the westernmost), Clubiona norvegica (the easternmost in Asia), Pachygnatha listeri , Helophora insignis and Mitopus morio (the northernmost in Asia) and Oreoneta leviceps (the southernmost in the Palaearctic). Three species, Oreoneta eskovi, Pardosa oljunae and Thaleria orientalis, are endemics of West Siberia. About two-thirds of the species are either circum-Holarctic or trans-Palaearctic.

Pioneer zone geo-ecological change: Observations from a chronosequence on the Storbreen glacier foreland, Jotunheimen, southern Norway

The first 33years of primary geo-ecological succession is investigated in the pioneer zone of the Storbreen glacier foreland using the chronosequence approach. Pitfall trapping of invertebrates and the sampling of higher and lower plants and habitat factors from quadrats were used on three replicate transects across a till plain accurately dated by annually monitored glacier front variations combined with the mapping of annual moraine ridges. Unstable, saturated sediments deglacierized for <1year are colonized first by very large numbers of Collembola and a small number of epigeal beetles and spiders. Improved drainage, loss of fine matrix by pervection and frost sorting lead to the development of an active stone pavement after 6–21years, which is colonized by sparse herbaceous perennials, a slowly-developing cryptogamic crust dominated by mosses, and moderately abundant epigeal beetles, spiders and the glacier harvestman (Mitopus morio). Further soil development and stabilization of the stone pavement lead, via a transition phase (21–26years), to a fast developing ecosystem (26–33years) in which the cover of most of the plants and pitfall catches of invertebrate groups are increasing rapidly (including a resurgence in Collembola catches and the spread of Racomitrium moss, terrestrial lichens and shrubs). Spatial heterogeneity reflects gradual successional trajectories related to small variations in physical habitat conditions. The sequence of changes is summarized in a conceptual geo-ecological model in which abiotic and biotic processes combine to drive the pioneer stages of both invertebrate and plant succession with little evidence of highly integrated biotic communities.

Food Choice of Invertebrates During Early Glacier Foreland Succession

Bryophytes from seven different genera colonized 3- to 6-year-old ground near a receding glacier in central South Norway. Microscopic studies of the gut content in pioneer invertebrates revealed that mosses were grazed upon by four species: an abundant and large Collembola (Bourletiella hortensis), a moss-eating Byrrhidae beetle (Simplocaria metallica), and two omnivorous Carabidae beetles (Amara alpina and A. quenseli). The three most abundant moss species were preferred by the moss-eaters: Pohlia filum, Ceratodon purpureus, and Bryum arcticum. Special parts of the moss plant could be selected. Three other Collembola species present were classified as herbivores because they had diatom algae in their gut, indicating that they grazed on terrestrial biofilm. Chironomidae midges hatching from young ponds represented an important element in the gut content of three common predators: the Opiliones Mitopus morio, and two Carabidae beetles Nebria nivalis and Bembidion hastii. The present data show that chlorophyll-based food chains start almost immediately on bare ground, but in a rather invisible way by tiny pioneer mosses and terrestrial biofilm with diatom algae. Pioneer mosses may be regarded as “drivers” in early animal succession, before higher plants establish. Since several of the pioneer invertebrates were herbivores or omnivores, the present community did not fit with the “predator first” hypothesis.

Alpine activity patterns of Mitopus morio (Fabricius, 1779) are induced by variations in temperature and humidity at different scales in central Norway

Our research addresses questions about how micro-climate affects activity abundance of a common and widespread harvestman in an alpine ecosystem. Activity patterns of the Harvestman Mitopus morio (Fabricius, 1779) were studied along different alpine gradients in the central Norwegian Scandes. Within a nested design, we surveyed 18 alpine habitats with pitfall traps and micro-climatological equipment along oceanic-continental, two elevational, and (fine-scaled) microtopographic gradients. Sites in the oceanic region of the Scandes showed generally higher abundance of M. morio than sites in the continental region. Furthermore, along the elevational gradient, middle-alpine sites showed higher abundances than low-alpine sites. These general patterns are best explained by higher humidity in the oceanic region and in the middle-alpine belt. Focusing at a finer scale, i.e. one elevational level within each region, revealed partly opposing activity patterns within relatively short distances. While in the western middle-alpine belt these patterns were best explained by humidity-related measures but now with higher activity abundance during drier conditions, in the drier eastern middle-alpine belt heat sums rather than humidity were found to be the best explanatory variables for the observed patterns. Hence, our results imply a pronounced different reaction of the two populations towards climatic variables that partly even contradict the previously described general pattern. Regardless whether these differences in activity abundance in M. morio are a form of phenotypic plasticity or adaptation, our findings stress the importance of detailed autecological knowledge combined with fine-scaled climatic measurements when aiming at predictions about possible future ecosystem structures and spatio-temporal phenomena. M. morio proves to be an ideal biogeographic model organism for understanding spatio-temporal responses of alpine ecosystems under modified climatic conditions.

How diverse is Mitopus morio? Integrative taxonomy detects cryptic species in a small‐scale sample of a widespread harvestman

Mitopus morio is a widespread harvestman species occurring in most of Europe and in moderate and cold-moderate zones of Asia and North America. The species is characterized by extreme variability in body size and leg length. As leg length is correlated with habitat temperature, M.morio has been considered as an example of Allen's rule. Recently, observations for a single location in Tyrol, Austria, indicated the absence of mating between short- and long-legged individuals. This study examines for signs of putative cryptic species in M.morio using an integrative approach that combines mating trials, amplified fragment length polymorphism whole-genome scans, mitochondrial sequences and morphometrics. The mating trials did not corroborate the initial hypothesis of a reproductive barrier associated with leg size. Both types of genetic data revealed the existence of three distinct groups, in line with the mating results but largely unrelated to leg morphology and geographical origin of specimens. Morphometric characters supporting the findings of the other disciplines were identified using a supervised approach. We infer from all data together the existence of strongly diverged cryptic lineages among the analysed individuals, cautiously interpret them as three sympatric species and conclude that in these harvestmen Allen's rule applies at different levels. Due to the unexpected amount of differentiation found within a geographical scale very small compared with the distribution of M.morio, we suggest a thorough revision of the genus prior to formal taxonomic changes. Our case study underlines the general applicability of the integrative taxonomic protocol used and highlights the relevance of several rationales implemented in the protocol.

Testing the ‘addition and persistence model’ of invertebrate succession in a subalpine glacier-foreland chronosequence: Fåbergstølsbreen, southern Norway

Invertebrate primary succession is investigated across a chronosequence in the subalpine (birch woodland) zone at Fåbergstølsbreen using pitfall traps. Presence and abundance of taxa, functional groups and communities are examined using a geo-ecological approach including mapping, graphical analysis, two-way indicator species analysis (TWINSPAN) and non-metric multidimensional scaling (NMS). Twenty-nine of the 67 recorded taxa, and 14 of the 37 epigeal (surface active) taxa colonize terrain deglacierized for &lt;20 years and catches of most of these pioneer taxa attain an early peak on terrain deglacierized for &lt;40 years. Catches of most later colonizers peak in the mature (‘climax’) stage where 86% of the pioneer taxa and 79% of the epigeal pioneers are also recorded. The number of taxa increases across the chronosequence as new taxa, predominantly predators, appear but relatively few taxa drop out of the succession, and as the dominant species in the traps changes from the harvestman, Mitopus morio, to the wood ant, Formica lugubris. The invertebrate communities are interpreted as loosely organized groupings of individualistic species, the distributions of which are strongly related to terrain age. Changes during succession are interpreted as driven primarily by competition between the carnivorous taxa, though herbivores and omnivores comprise up to 24% and 11% of the taxa, respectively, in both pioneer and mature zones. Hence the ‘addition and persistence model’ of invertebrate succession, previously proposed for the alpine zone, is largely substantiated but partially modified for the subalpine zone, where succession is generally more rapid, overall changes during succession are greater, communities are better organized, food webs appear better developed, and there is an element of replacement change in the later stages.

Cold hardiness and development rate as elements of adaptive strategies of phalangiid harvestmen (Opiliones, Phalangiidae) in northeastern Asia

Three species of phalangiid harvestmen (Mitopus morio, Homolophus arcticus, and Oligolophus tienmushanensis) were studied. These species overwinter at the egg stage and have embryonic diapause, suppressing hatching in autumn and preventing death from low temperatures. The eggs do not survive freezing, but can be supercool. The comparison of the growth rate under natural conditions and in containers with controlled temperature indicates that in the seasons with unfavorable climatic conditions, not all individuals have time to lay eggs before cold weather sets in; however, in favorable seasons, oviposition occurs approximately 30–45 days before the death of the adults. The high cold hardiness of M. morio and H. arcticus eggs suggests that the northward distribution of these species cannot be limited by low winter temperatures. The cold hardiness of O. tienmushanensis also does not appear to prevent their colonization of most biotopes of the region, except for those having a thin snow cover or no cover at all. However, this colonization does not happen. The northward distribution of O. tienmushanensis appears to be restricted by some other factors.

Detoxification of pyrrolizidine alkaloids by the harvestman Mitopus morio (Phalangidae) a predator of alkaloid defended leaf beetles

The harvestman Mitopus morio (Phalangidae) is a generalist predator. It is known to prey on larvae of the chrysomelid leaf beetle Oreina cacaliae defended by plant acquired pyrrolizidine alkaloids (PAs). Tracer feeding experiments were performed to determine how harvestmen tolerate protoxic PAs. Minced meat containing either [14C]senecionine or [14C]senecionine N-oxide was fed to M. morio and subsequently feces and bodies were analyzed. Labeled alkaloid N-oxide remained stable and was eliminated almost unaltered with the feces; only 10% was recovered as tertiary PA. In contrast, approximately 80% of labeled tertiary alkaloid (senecionine) ingested with the diet was N-oxidized and eliminated; the remaining 20% consisted of unchanged senecionine and a polar metabolite of unknown structure. Harvestmen process their diet by excreting digestive juice, indicated by bleaching of the meat color. Analysis of the processed diet revealed some N-oxidation of [14C]senecionine, suggesting the gut as the site of Noxidation. Analysis of the bodies of harvestmen 80 hours after the tracer feeding pulse revealed only trace amounts of the polar metabolite. Neither senecionine nor its N-oxide could be detected in the body extracts. The results are discussed in relation to the strategies of PA adapted insects to avoid accumulation of tertiary PAs in living tissues.

Harvestmen abundance and diversity within lodgepole and Scots pine plantations of Scotland and their impact on pine beauty moth populations

Natural enemies are important contributors to the differences in Panolis flammea abundance observed in Scots pine and lodgepole pine plantations in Scotland. This study compared the diversity and abundance of harvestmen species in Scots pine sites and lodgepole pine sites within forests of Northern Scotland. While the native Scots pine sites have never been affected by high numbers of P. flammea, the chosen lodgepole pine sites have had extensive P. flammea outbreaks in the past. Three harvestmen species, Mitopus morio, Oligolophus palpinalis and Oligolophus tridens had markedly different abundances between the forest habitats over the sampling period. Peaks in harvestmen abundance within the Scots pine habitat occurred at a time when P. flammea larvae were most vulnerable to attack (as early instar larvae). In contrast, the abundance of harvestmen within the lodgepole pine habitat was low at this vulnerable time but peaked later in the summer at a time when P. flammea were least affected by predation.

Observations on larval mites (Acari) parasitic on Opiliones from the French Pyrenees

Larval mites (Acari) parasitic on Opiliones from the French Pyrenees were studied. Three species of the genus Leptus (Erythraeidae) were collected two of which were already described: Leptus ignotus (Oudemans) collected from Phalangium opilio and Leptus beroni Fain (syn. Leptus holmiae Southcott) from Mitopus morio, Megabunus diadema and Oligolophus hansenii. The third species, Leptus gyas sp.n., was collected from Gyas titanus.. In addition, a second new species, Tetrathrombium gabasense sp.n. (Johnstonianidae), was collected from moss, covering a beech which also harboured Megabunus diadema, infested with Leptus beroni. These new species are described.

GROUND-LIVING SPIDERS, OPILIONIDS, AND PSEUDOSCORPIONS OF PEATLANDS IN QUEBEC

AbstractPeatlands were studied in temperate, boreal, subarctic, and arctic wetland regions of Quebec, mainly using pitfall traps. Altogether, 169 species of spiders, belonging to 14 families, were collected; 73 species were found only in the temperate-boreal region, 58 only in the subarctic-arctic region, and 38 in both regions. The most species-rich spider families were Linyphiidae (58.3% of all species), Lycosidae (12.4%), and Gnaphosidae (7.1%). Families occurring only, or mainly, in the temperate (and boreal) region were Hahniidae, Dictynidae, Salticidae, Liocranidae, and Theridiidae. Linyphiidae, especially Erigoninae, were typical of the subarctic region. Alopecosa aculeata (Clerck) and Pardosa hyperborea (Thorell) (Lycosidae), Theonoe stridula Crosby (Theridiidae), and Ceratinella brunnea Emerton (Linyphiidae) were found in six of the seven study areas. Seven of the eight opilionid species were found in the temperate region, but Mitopus morio (Fabricius) occurred only in the subarctic bogs. The only pseudoscorpion, Microbisium brunneum (Hagen), was caught in the temperate, boreal, and subarctic regions. The percentage of spiders collected in bogs of both Quebec and southern Ontario was 64% in the temperate region and only 27% in the subarctic region. Almost 50% of species from bogs in the Manitoba taiga were found also in Quebec. About a third of the Quebec bog spiders are Holarctic.

Two new larvae of the genusLeptuslatreille, 1796 (Acari, Erythraeidae) from Belgium

ABSTRACT Two new parasitic larval mites of the genus Leptus Latreille, 1796 (Acari, Erythraeidae) are described from Belgium: Leptus cooremani n.sp. from an unidentified butterfly and L. beroni n.sp. from a phalangiid, Mitopus morio (F.)

Hemocytes of Leiobunum limbatum and two other species of harvestmen (Arachnida, Opiliones): Morphological classification and functional aspects.

The hemocytes of Leiobunum limbatum, Mitopus morio, and Opilio ravennae number from about 8,000 (juveniles) to 41,000 (pregnant females) per microliter of hemolymph. Five different types of hemocytes occur in all three species and both sexes. According to their ultrastructural appearance and their similarities to other arthropod hemocytes these five types are designated as prohemocyte, plasmatocyte, granulocyte, coagulocyte, and spherulocyte. From the ultrastructural point of view the prohemocytes are interpreted as stem cells for plasmatocytes which on their part differentiate into granulocytes. Transitional stages which would indicate the origin of coagulocytes and spherulocytes could not be found. Granulocytes and spherulocytes are interpreted as being storage cells; coagulocytes burst when hemolymph is transferred to a microscopic slide. Plasmatocytes are involved in the removal of dead cells or cell fragments. Plasmatocytes are demonstrated as being able to phagocytize and digest bacteria.

Ultrastructure and function of the circulatory organs of Leiobunum limbatum and two other species of harvestmen (arachnida: Opiliones).

The ultrastructure of the circulatory organs of Leiobunum limbatum, Mitopus morio, and Rilaena triangularis (Arachnida: Opiliones) has been investigated. We studied the organization of the heart, the myocardial contractile elements, its tubular system, organelles, and cell-junctions. The epicardium exhibits a large number of longitudinally arranged microtubules and is attached to the myocardium by special membrane complexes. Because of these structures, the epicardium is interpreted as the elastic antagonist to the heart muscle. At both ends of the heart the epicardium continues into a nonbranching aorta. Consequently the ultrastructure of the aortal wall, containing numerous microtubules, is similar to the ultrastructure of the epicardium. At the posterior end of the heart is a muscular slit-valve, while at the anterior end is a lobe-valve that lacks contractile elements. The heart is innervated by a dorsal ganglion. It covers the entire length of the heart and contains neural and glial cells. Two different types of neurosecretory granules and both electron-dense and electron-lucent synaptic vesicles are described.