Evolution of distribution and habitat patterns in endemic millipedes of the genus Dolichoiulus (Diplopoda: Julidae) on the Canary Islands, with notes on distribution patterns of other Ganarian species swarms

Forty-six species of the genus Dolichoiulus , all endemic, occur on the Canary Islands The highest number of species occur on the largest, highest island (Tenerife); fewest occur on Lanzarote, Fuerteventura (low, xeric), El Hierro and La Palma (small, remote). Most of the Dolichoiulus species live on one island only, as in other endemic Canarian species swarms. The scarcity of pluri-insular Dolichoiulus species, in connection with information on phylogeny, suggests that speciation has mainly taken place within individual islands. Distribution patterns are partly governed by habitat differences between species, but vicariance patterns between species living in the same kind of habitat are evident on La Gomera and Tenerife. Dolichoiulus species occur in all kinds of natural habitats. Laurisilva and cave species are generally paler than other species. In the laurisilva of eastern Tenerife, microhabitat differentiation between species is pronounced. In some, but far from all, cases, species coexisting in the same microhabitat are of different sizes. The ancestral colonizing species of Dolichoiulus is/are hypothesized to have been small and to have lived in coastal habitats. Colonization of higher altitudes was usually accompanied by an increase in body size. Invasion of the laurisilva was usually accompanied by a habitat shift from the ground layer to logs.     

Photosynthetic use of inorganic carbon among primary and secondary water plants in streams

1. We analysed photosynthetic rates and inorganic carbon use of thirty-five vascular macrophyte species collected submerged in eight nutrient- and CO₂-rich Danish lowland streams. The species were classified in four groups as mainly terrestrial, homophyllous and heterophyllous amphibious and truly submerged. These groups represent plant species differently adapted to life in water. 2. Photosynthetic rates measured in water increased in the gradual transition from mainly terrestrial, through amphibious to truly submerged species. Species normally in contact with air adapted to submergence by increasing the photosynthetic rate at limiting CO₂. Photosynthetic rates of submerged parts of heterophyllous amphibious species were close to those of submerged species. Submerged species with thin or finely dissected leaves had the highest photosynthetic rates, probably because of low diffusional resistance to uptake of nutrients and gases. 3. In contrast to submerged species, terrestrial and amphibious species were unable to use HCO₃^?. Extensive oversaturation with CO₂ in the streams allows, however, many amphibious species to photosynthesize well under water, based on CO₂-use alone. Amphibious CO₂-users, with very few structural adaptations to life under water, can therefore be as dominant in the submerged vegetation of lowland streams as HCO₃^?-using water plants. Moreover, the streams provide open space for colonization from the dense vegetation ashore. 4. Among the 1265 Danish herbaceous species no less than seventy-five terrestrial species occasionally grow submerged, forty-five species are amphibious, and fifty-one are true water plants. These numbers suggest that adaptation to permanent or temporary submergence is an ongoing process involving many species and that the land-water interface does not represent as difficult a barrier as often believed.     

Bacterial metabolism in small temperate streams under contemporary and future climates

1. We examined the detailed temperature dependence (0–40 °C) of bacterial metabolism associated with fine sediment particles from three Danish lowland streams to test if temperature dependence varied between sites, seasons and quality of organic matter and to evaluate possible consequences of global warming. 2. A modified Arrhenius model with reversible denaturation at high temperatures could account for the temperature dependence of bacterial metabolism and the beginning of saturation above 35 °C and it was superior to the unmodified Arrhenius model. Both models overestimated respiration rates at very low temperatures (<5 °C), whereas Ratkowsky's model – the square root of respiration – provided an excellent linear fit between 0 and 30 °C. 3. There were no indications of differences in temperature dependence among samples dominated by slowly or easily degradable organic substrates. Optimum temperature, apparent minimum temperature, Q₁₀‐values for 0–40 °C and activation energies of bacterial respiration were independent of season, stream site and degradability of organic matter. 4. Q₁₀‐values of bacterial respiration declined significantly with temperature (e.g. 3.31 for 5–15 °C and 1.43 for 25–35 °C) and were independent of site and season. Q₁₀‐values of bacterial production behaved similarly, but were significantly lower than Q₁₀‐values of respiration implying that bacterial growth efficiency declined with temperature. 5. A regional warming scenario for 2071–2100 (IPCC A2) predicted that mean annual temperatures will increase by 3.5 °C in the air and 2.2–4.3 °C in the streams compared with the control scenario for 1961–1990. Temperature is expected to rise more in cool groundwater‐fed forest springs than in open, summer‐warm streams. Mean annual bacterial respiration is estimated to increase by 26–63% and production by 18–41% among streams assuming that established metabolism–temperature relationships and organic substrate availability remain the same. To improve predictions of future ecosystem behaviour, we further require coupled models of temperature, hydrology, organic production and decomposition.     

Physicochemical characterization of pituitary follicle-stimulating hormone

The physiochemical characteristics of the follicle-stimulating hormone (FSH) from whole sheep pituitary glands have been studied. The hormone behaves as a single protein in electrophoresis, diffusion, and ultracentrifugation. It has an isoelectric point at pH 4.5 and a molecular weight of 67,000 and contains 1.23 per cent hexose and 1.51 per cent hexosamine. The amino acid composition has also been determined in large part. The stability of the hormone to acid and heat has been investigated.     

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.     

Genetic variation in three species of Epipactis (Orchidaceae): geographic scale and evolutionary inferences

The breeding system is expected to strongly influence the genetic structure of plant populations. In the present study, isozyme variation is documented in Danish populations of three species of Epipactis , varying in breeding system from allogamy to obligate autogamy. The allogamous and widespread E. helkborine subsp. helkborine shows high levels of polymorphism. Most of the genetic variation is found within local populations. A hierarchical analysis indicates significant among-population differentiation, but no regional differentiation in E. helkborine is apparent. This may be due to higher levels of gene flow in the past, before forest was fragmented. The ecotype from coastal dunes, E. helleborine subsp. neerlandka , does not differ from E. helkborine subsp. helkborine in any of the examined loci, but it has a significant population inbreeding coefficient that can probably be explained by higher levels of geitonogamy and the possibility of spontaneous autogamy. The entomophilous E. purpurata and the obligately autogamous E. phylhmthes are monomorphic at all loci examined. Several factors, including a founder effect at the time of colonization, high levels of geitonogamy, as well as habitat specialization combined with erratic flowering may have contributed to the lack of variation in E. purpurata. The lack of variation in the autogamous E. phyllanthes is probably due to inbreeding. It is proposed diat autogamy in Epipactis may in some cases have evolved through paedomorphosis of allogamous flowers and that the occurrence of local breeding groups may have facilitated the speciation process.     

The Effects of Breeder Loss on Wolves

Abstract Managers of recovering wolf (Canis lupus) populations require knowledge regarding the potential impacts caused by the loss of territorial, breeding wolves when devising plans that aim to balance population goals with human concerns. Although ecologists have studied wolves extensively, we lack an understanding of this phenomenon as published records are sparse. Therefore, we pooled data (n = 134 cases) on 148 territorial breeding wolves (75 M and 73 F) from our research and published accounts to assess the impacts of breeder loss on wolf pup survival, reproduction, and territorial social groups. In 58 of 71 cases (84%), ≥1 pup survived, and the number or sex of remaining breeders (including multiple breeders) did not influence pup survival. Pups survived more frequently in groups of ≥6 wolves (90%) compared with smaller groups (68%). Auxiliary nonbreeders benefited pup survival, with pups surviving in 92% of cases where auxiliaries were present and 64% where they were absent. Logistic regression analysis indicated that the number of adult-sized wolves remaining after breeder loss, along with pup age, had the greatest influence on pup survival. Territorial wolves reproduced the following season in 47% of cases, and a greater proportion reproduced where one breeder had to be replaced (56%) versus cases where both breeders had to be replaced (9%). Group size was greater for wolves that reproduced the following season compared with those that did not reproduce. Large recolonizing (>75 wolves) and saturated wolf populations had similar times to breeder replacement and next reproduction, which was about half that for small recolonizing (≤75 wolves) populations. We found inverse relationships between recolonizing population size and time to breeder replacement (r= —0.37) and time to next reproduction (r= —0.36). Time to breeder replacement correlated strongly with time to next reproduction (r=0.97). Wolf social groups dissolved and abandoned their territories subsequent to breeder loss in 38% of cases. Where groups dissolved, wolves reestablished territories in 53% of cases, and neighboring wolves usurped territories in an additional 21% of cases. Fewer groups dissolved where breeders remained (26%) versus cases where breeders were absent (85%). Group size after breeder loss was smaller where groups dissolved versus cases where groups did not dissolve. To minimize negative impacts, we recommend that managers of recolonizing wolf populations limit lethal control to solitary individuals or territorial pairs where possible, because selective removal of pack members can be difficult. When reproductive packs are to be managed, we recommend that managers only remove wolves from reproductive packs when pups are ≥6 months old and packs contain ≥6 members (including ≥3 ad-sized wolves). Ideally, such packs should be close to neighboring packs and occur within larger (≥75 wolves) recolonizing populations.     

CHARACTERISTICS OF TERRITORIAL AND MATING CALLS IN WILLOW PTARMIGAN LAGOPUS L. LAGOPUS

ABSTRACT

During territorial behaviour and pair formation willow ptarmigan cocks and hens use several different calls. Cocks use mainly a “flight call”, a “ground call” and three different “threat calls”. Hens give similar calls to cocks. It is suggested that the structure of the calls is well adapted to (1) transmit their possible information content over long distances, and (2) make localization easier for birds during the territorial display periods, which take place mainly in poor light at dusk and dawn. We also suggest that the cock and hen calls express different degrees of aggressiveness, and that hen calls, in addition to attracting cocks, function as territorial “keep out” signals to other hens.