Aggregation in the tropical millipede Alloporus uncinatus (Diplopoda: Spirostreptidae)

Millipedes tend to have a near random dispersion pattern when surface active. Only in a few species do juvenile stadia form dense swarms. This study describes the occurrence and composition of aggregations in an adult population of the tropical spirostreptid millipede Alloporus uncinatus (Attems) inhabiting riparian forest in Zimbabwe. Also presented are the results of a field experiment designed to induce aggregation behaviour in a separate population with the addition of high quality food to the habitat.
Our initial hypothesis that the natural aggregations of between six and 42 individuals observed during the period of surface activity were part of the mating system in this species was refuted. Few mature males were present in aggregates and less than 1%, of copula pairs sampled were taken from aggregates. The composition of aggregates and the results of the experiment suggest that aggregations are associated with the feeding activities of immature individuals and are not related to reproductive activity. We suggest that the aggregations observed in A. uncinatus , although related, may perform different functions to the swarming behaviours observed in other millipede species.     

The anal glands of Rhapidostreptus virgator (Diplopoda: Spirostreptidae)

Summary In Rhapidostreptus virgator exocrine gland complexes are found in the anal valves of both sexes. Every gland complex consists of about 200 secretory units, each of which is comprised of four cells: two secretory cells, an intermediary cell, and a canal cell. The amount of secretion produced by these glands varies during the intermoult cycle: it is very small in freshly moulted individuals (postmoult phase), at a medial level during the following intermoult phase, and very large in the premoult phase. The secretion may be used to form the excrement clumps and above all to build the moulting chamber.     

Behavioural thermoregulation of Orthopoms ornatus (Diplopoda: Spirostreptidae) in three desert habitats

Observations on feeding and locomotion of the desert millipede Orthopoms ornatus were made in three separate habitats during the summer feeding season. The habitats were Tornillo Flat in Big Bend National Park, Texas; the Jornada Validation Site of IBP/Desert Biome near Las Cruces, New Mexico; and the base of a volcanic escarpment near Albuquerque, New Mexico.
In each habitat diurnal or diel temperatures were monitored in a typical millipede microsite. Microsites included portions of a Larrea/Opuntia shrub complex (Tornillo Flat), an Ephedra shrub (Jornada Site), and a Salsola shrub (Albuquerque). Adjacent mammal-burrow temperatures were also monitored, as were soil-surface temperatures (two habitats) and air temperatures (one habitat).
Diurnal feeding and locomotion were greatest in early morning and late afternoon; nocturnal activity also occurred. Soil-surface activity generally ceased before surface temperatures reached 35^oC and began again when they cooled to about the same level. In the meantime, movement to burrows, to beneath rocks and vegetation, and to aerial portions of shrubs occurred. Additional behavioural thermoregulation was manifested by horizontal and vertical movements within shrubs, maximum air temperatures encountered being 35.5^oC.
Such behaviour is considered in light of recent studies of water balance and metabolism in this species.     

Thermal Preference of Juvenile Dover Sole (Solea solea) in Relation to Thermal Acclimation and Optimal Growth Temperature

Dover sole (Solea solea) is an obligate ectotherm with a natural thermal habitat ranging from approximately 5 to 27°C. Thermal optima for growth lie in the range of 20 to 25°C. More precise information on thermal optima for growth is needed for cost-effective Dover sole aquaculture. The main objective of this study was to determine the optimal growth temperature of juvenile Dover sole (Solea solea) and in addition to test the hypothesis that the final preferendum equals the optimal growth temperature. Temperature preference was measured in a circular preference chamber for Dover sole acclimated to 18, 22 and 28°C. Optimal growth temperature was measured by rearing Dover sole at 19, 22, 25 and 28°C. The optimal growth temperature resulting from this growth experiment was 22.7°C for Dover sole with a size between 30 to 50 g. The temperature preferred by juvenile Dover sole increases with acclimation temperature and exceeds the optimal temperature for growth. A final preferendum could not be detected. Although a confounding effect of behavioural fever on temperature preference could not be entirely excluded, thermal preference and thermal optima for physiological processes seem to be unrelated in Dover sole.     

Anatomy and histology of the alimentary tract of the desert millipede Orthoporus ornatus (Girard) (Diplopoda: Spirostreptidae)

The alimentary tract of the desert millipede Orthoporus ornatus is essentially a straight tube consisting of a histologically distinct foregut, midgut, pylorus, hindgut, and rectum. Common to each region, but often different in regional appearance, are an outer sheath layer, longitudinal and circular muscle layers, a basement membrane, and an inner epithelial layer. Foregut and midgut lumina are lined by a cuticular intima, while a peritrophic membrane occurs in the midgut lumen. Gut structure is considered in the context of the known feeding habits and digestive efficiency of this long-lived, seasonally restricted detritivore.     

Millipede (Diplopoda) communities in an arboretum: Influence of tree species and soil properties

The paper deals with the influence of tree species on millipede communities (Diplopoda). The research was carried out in nine sites in the Borová hora arboretum (Zvolen town, Central Slovakia). Each studied site represents a monoculture of one of nine tree species: Betula pubescens Ehrh., Pinus sylvestris L., Larix decidua Mill., Carpinus betulus L., Abies alba Mill., Picea abies (L.) Karst., Alnus incana (L.) Moench, Populus nigra L., Ulmus laevis Pall. Millipedes were collected by pitfall trapping during vegetation periods in 2008-2011. In total, 1064 individuals of 17 species and 7 families were obtained. The results of research confirmed (i) an influence of tree species on the composition of millipede communities, (ii) a significant influence of soil nitrogen on the species richness and biodiversity, and (iii) an impact of soil pH on the species composition of these terrestrial invertebrate communities. In terms of total dynamic activity and species richness of millipedes, the most favourable conditions were revealed in the forest stands of Alnus incana, Populus nigra, Ulmus laevis and Carpinus betulus. On the contrary, the least favourable biotopes were (from both points of view) the forest stands of Betula pubescens and Larix decidua.     

Haplopodous Diplopods: A New Type of Millipede Body Construction Discovered in Cambalopsid Juveniles (Diplopoda,Spirostreptida)

Abstract Early juvenile stadia are described in four species of family Cambalopsidae. Hypocambala helleri Silvestri, 1897, and H. anguinea (Attems, 1900) show normal relationships between numbers of podous and apodous rings, and numbers of leg-pairs. Glyphiulus granulatus (Gervais, 1847) and Trachyiulus tjampeanus (Attems, 1903) have a deviating stadium (probably stadium III) in which most of the podous rings (10–13 rings in G. granulatus, 19 rings in T. tjampeanus) have only one leg-pair. No trace of the anterior leg-pair, nor of its sternum, could be found in these rings. At the moult to the next stadium (?IV), the normal, diplopodous condition is restored. The term haplopodous diplopods is suggested for the deviating juveniles of G. granulatus and T. tjampeanus. The haplopodous condition creates potential problems for palaeontology and indicates a closer relationship between Glyphiulus and Trachyiulus than reflected in current classifications.     

Extensive Acclimation in Ectotherms Conceals Interspecific Variation in Thermal Tolerance Limits

Species’ tolerance limits determine their capacity to tolerate climatic extremes and limit their potential distributions. Interspecific variation in thermal tolerances is often proposed to indicate climatic vulnerability and is, therefore, the subject of many recent meta-studies on differential capacities of species from climatically different habitats to deal with climate change. Most studies on thermal tolerances do not acclimate animals or use inconsistent, and insufficient, acclimation times, limiting our knowledge of the shape, duration and extent of acclimation responses. Consequently patterns in thermal tolerances observed in meta-analyses, based on data from the literature are based on inconsistent, partial acclimation and true trends may be obscured. In this study we describe time-course of complete acclimation of critical thermal minima in the tropical ectotherm Carlia longipes and compare it to the average acclimation response of other reptiles, estimated from published data, to assess how much acclimation time may contribute to observed differences in thermal limits. Carlia longipes decreased their lower critical thermal limits by 2.4°C and completed 95% of acclimation in 17 weeks. Wild populations did not mirror this acclimation process over the winter. Other reptiles appear to decrease cold tolerance more quickly (95% in 7 weeks) and to a greater extent, with an estimated average acclimation response of 6.1°C. However, without data on tolerances after longer acclimation times available, our capacity to estimate final acclimation state is very limited. Based on the subset of data available for meta-analysis, much of the variation in cold tolerance observed in the literature can be attributed to acclimation time. Our results indicate that (i) acclimation responses can be slow and substantial, even in tropical species, and (ii) interspecific differences in acclimation speed and extent may obscure trends assessed in some meta-studies. Cold tolerances of wild animals are representative of cumulative responses to recent environments, while lengthy acclimation is necessary for controlled comparisons of physiological tolerances. Measures of inconsistent, intermediate acclimation states, as reported by many studies, represent neither the realised nor the potential tolerance in that population, are very likely underestimates of species’ physiological capacities and may consequently be of limited value.     

Thermal Acclimation of Respiration and Photosynthesis in the Marine Macroalga Gracilaria lemaneiformis (Gracilariales,Rhodophyta)

The responses of respiration and photosynthesis to temperature fluctuations in marine macroalgae have the potential to significantly affect coastal carbon fluxes and sequestration. In this study, the marine red macroalga Gracilaria lemaneiformis was cultured at three different temperatures (12, 19, and 26°C) and at high‐ and low‐nitrogen (N) availability, to investigate the acclimation potential of respiration and photosynthesis to temperature change. Measurements of respiratory and photosynthetic rates were made at five temperatures (7°C–33°C). An instantaneous change in temperature resulted in a change in the rates of respiration and photosynthesis, and the temperature sensitivities (i.e., the Q₁₀ value) for both the metabolic processes were lower in 26°C‐grown algae than 12°C‐ or 19°C‐grown algae. Both respiration and photosynthesis acclimated to long‐term changes in temperature, irrespective of the N availability under which the algae were grown; respiration displayed strong acclimation, whereas photosynthesis only exhibited a partial acclimation response to changing growth temperatures. The ratio of respiration to gross photosynthesis was higher in 12°C‐grown algae, but displayed little difference between the algae grown at 19°C and 26°C. We propose that it is unlikely that respiration in G. lemaneiformis would increase significantly with global warming, although photosynthesis would increase at moderately elevated temperatures.     

Morphology of the mandibles in the millipedes (Diplopoda, Arthropoda)

The mouthparts of seven species from five families of Diplopoda have been investigated with scanning electron microscopy. The distal segment of the mandible, the gnathal lobe, is the most complex structure. Although the biting and crushing parts among the examined genera arc always based on the same general scheme, typical modifications of these structures exist which are regarded to be taxon-specific. The density of the teeth on the pectinate lamellae appears to determine the size of the ingested food particles. A well-developed anterior fringe does not seem to be necessary for the ingestion of food.     

A revision of the Siphonocryptidae (Diplopoda, Polyzoniida)

Siphonocryptus compactus Pocock, 1894 (Sumatra), is redescribed from type and fresh material. Siphonocryptus latior sp. n. (Malaya) is described. Hirudicryptus gen. n. (monotypic) is erected, type-species Siphonocryptus canariensis Loksa, 1967 (Canary Islands, Madeira). Arguments for monophyly of Siphonocryptidae (= Siphonocryptus + Hirudicryptus ) and for a sister-group relationship between Siphonocryptidae and all other Polyzoniida arc presented. The strongly disjunct distribution area of the family is compared with other disjunct distributions involving the Canary Islands and Madeira.     

A New Dimension in Documenting New Species: High-Detail Imaging for Myriapod Taxonomy and First 3D Cybertype of a New Millipede Species (Diplopoda,Julida, Julidae)

We review the state-of-the-art approaches currently applied in myriapod taxonomy, and we describe, for the first time, a new species of millipede (Ommatoiulus avatar n. sp., family Julidae) using high-resolution X-ray microtomography (microCT) as a substantive adjunct to traditional morphological examination. We present 3D models of the holotype and paratype specimens and discuss the potential of this non-destructive technique in documenting new species of millipedes and other organisms. The microCT data have been uploaded to an open repository (Dryad) to serve as the first actual millipede cybertypes to be published.     

Ecology of Chondromorpha kelaarti (Diplopoda, Polydesmida)

Stadia 11-VII and adults of Chondromorpha kelaarti (Humbert) can be separated by segment number, length, breadth and paired legs. Sexes are distinguished from stadium IV and the sex ratio vaned around SO%, though females were prevalent in May and June.
In females, a positive and significant correlation was found between number ofeggs present and body width at the 17th Segment.
Population density and biomass of C. kelaarti varied from 0.06 to 12.94 and 1.75 mg to 811.24 mg per 0.1 mz, respectively. From May to November, populations of C. kelaartiare aggregated in distribution.
Chondronrorphu keluurti passed the dry season in late stadia (VI, VII and adult) and may complete the life cycle in one or two years.     

The ultrastructure of the midgut epithelium in millipedes (Myriapoda,Diplopoda)

The midgut epithelia of the millipedes Polyxenus lagurus, Archispirostreptus gigas and Julus scandinavius were analyzed under light and transmission electron microscopies. In order to detect the proliferation of regenerative cells, labeling with BrdU and antibodies against phosphohistone H3 were employed. A tube-shaped midgut of three millipedes examined spreads along the entire length of the middle region of the body. The epithelium is composed of digestive, secretory and regenerative cells. The digestive cells are responsible for the accumulation of metals and the reserve material as well as the synthesis of substances, which are then secreted into the midgut lumen. The secretions are of three types – merocrine, apocrine and microapocrine. The oval or pear-like shaped secretory cells do not come into contact with the midgut lumen and represent the closed type of secretory cells. They possess many electron-dense granules (J. scandinavius) or electron-dense granules and electron-lucent vesicles (A. gigas, P. lagurus), which are accompanied by cisterns of the rough endoplasmic reticulum. The regenerative cells are distributed individually among the basal regions of the digestive cells. The proliferation and differentiation of regenerative cells into the digestive cells occurred in J. scandinavius and A. gigas, while these processes were not observed in P. lagurus. As a result of the mitotic division of regenerative cells, one of the newly formed cells fulfills the role of a regenerative cell, while the second one differentiates into a digestive cell. We concluded that regenerative cells play the role of unipotent midgut stem cells.     

Thermal sensitivity of a Neotropical amphibian (Engystomops pustulosus) and its vulnerability to climate change

A species’ thermal sensitivity and its exposure to climate variation are key components in the prediction of its vulnerability to climate change. We tested the thermal sensitivity of a tropical amphibian that lives in a mild constant climate in which the thermal tolerance range is expected to closely match the experienced environmental temperature. The air temperature that this species is exposed to varies between 21.9 and 31.6°C with an annual mean of 27.2°C. We estimated the microhabitat water temperature variation under vegetation shade, which buffers the temperature by 1.8°C in relation to that of the air, and with open canopy, where the water was 1.9°C warmer than the air temperature. With broods of tadpoles split into five treatments (15°C, 21°C, 28°C, 31°C, and 33°C), we estimated the critical thermal maximum (CTMax) and critical thermal minimum (CTMin) after at least 7 days of acclimation. Both CTMax (42.3°C) and CTMin (11.8°C) were more extreme than the temperature range estimated for the field. We estimated the optimum temperature (T_o = 28.8°C) and the thermal performance breadth (range: 23.3–34.1°C) based on growth rate (g/day). The animals were able to acclimate more extensively to cold than to warm temperatures. These performance curve traits closely matched the air temperature. The estimated vulnerability varied according to the microhabitat prediction model used. The combination of tadpole data on thermal sensitivity and macro‐ and microhabitat variation provides a necessary framework to understand the effects of climate change on tropical amphibians.