Evolutionary history of the complex polymorphic dobsonfly genus Neoneuromus (Megaloptera: Corydalidae)

The dobsonfly genus Neoneuromus van der Weele is endemic to the Oriental region. Species possess highly variable body and wing colouration and markings, not only among species but also among conspecific individuals of certain species. This stark polymorphism hinders accurate species identification, and obscures an undocumented species diversity as well as our understanding of the evolutionary history of this genus. We used multiple methods of molecular identification combined with morphological evidence to delimitate species, circumscribing a total of 13 species in Neoneuromus . Five new species are herein described: Neoneuromus indistinctus Liu, Hayashi & Yang, sp.n. , Neoneuromus maculatus Liu, Hayashi & Yang, sp.n. , Neoneuromus niger Liu, Hayashi & Yang, sp.n. , Neoneuromus similis Liu, Hayashi & Yang, sp.n. and Neoneuromus vanderweelei Liu, Hayashi & Yang, sp.n. The dated phylogeny with reconstructed ancestral areas indicates an initial divergence of Neoneuromus during the mid‐Eocene. A broad area including northeastern India and northern Indochina could be a centre for early divergence of the genus, while complex dispersal and vicariance events dating from the late Eocene to the Pliocene probably shaped the present diversity and distribution of the genus. Our ancestral character state reconstruction suggests that the pale and dark colour forms among different species, or conspecifics, could evolve rapidly and that changes in colouration could be driven by species‐specific mate recognition.     

HARD PATERNALISM,FAIRNESS AND CLINICAL RESEARCH: WHY NOT?

Jansen and Wall suggest a new way of defending hard paternalism in clinical research. They argue that non‐therapeutic research exposing people to more than minimal risk should be banned on egalitarian grounds: in preventing poor decision‐makers from making bad decisions, we will promote equality of welfare. We argue that their proposal is flawed for four reasons. First, the idea of poor decision‐makers is much more problematic than Jansen and Wall allow. Second, pace Jansen and Wall, it may be practicable for regulators to uncover the values that a potential research participant holds when agreeing to enter a research project, so their claim that we must ban such research projects for all if we are to ban them for poor decision‐makers looks to be unmotivated. Third, there seem to be cases where the liberty to enter the sort of research project Jansen and Wall discuss is morally weighty, and arguably should outweigh concerns of egalitarian distribution. Fourth, banning certain types of research, which seem on the face of it to offer an unfavourable risk‐benefit ratio, would have unwelcome consequences for all clinical research, which Jansen and Wall do not recognize.     

The macroinvertebrate fauna of the drainage channels of the Gwent Levels, South Wales

SUMMARY. From a survey of the fauna at sixty sites in permanent drainage channels of the Gwent Levels during the spring of 1976 and at some of these sites (thirty-three) during the autumn, speeies and site associations were identified using classification and ordination techniques. Sites in some groups had identifiahly similar environmental characteristics and grouping seemed particularly related to the vegetational stage in the hydrosere, water How and the incidence of salt contamination from the Severn Estuary. Characteristics which were common within particular species groups and whieh, in part, explained their distributions were: adaptation to low oxygen concentrations, food preferences and dispersal mechanisms. Whilst there was some temporal stability in site groups between the spring and autumn surveys, such associations were not idenlical. The oxygen status of channels appeared a major factor determining faunal distribution. Twelve sites, representing a range of channel types, were sampled six times in a 12-month period. Far more species were colleeled within the water column and on plants than in the benthos. Several oligochaetes, e.g. Aulodrilus pluriseta, Dero digitata, Limnodrilus claparedeanus, were not recorded at most sites during the summer probably because of the SUStained lack of oxygen at these sites. Three contiguous reaches of channel were maintained during the period March—October 1977 with different plant cover (no Lemnu; complete Lemna cover: control with partial Lemna cover). The oxygen status of the reaches was different, that with complete Lemna cover being continuously anaerobic near the channel bed for several months, the control reach which had partial Lemna cover being anaerobic for a shorter period and that with no Lemna being only anaerobic at night. Whilst the distribution of macroinvertebrate species was prineipally related to this oxygen status, the control reach whieh was strueturally the most complex, having both submerged and floating plants, contained about twiee as many species as the other reaches during the summer (colleeted in the water column and on plants): benthic samples in this and the reach with complete Lemna cover contained only between zero and two species during the period May- September.     

Neural function in an alpine grylloblattid: a comparison with the house cricket, Acheta domesticus

ABSTRACT. The effect of temperature on evoked activity in giant interneurons was compared in Grylloblatta sp. (an alpine insect with a temperature preference close to 0°C) and Acheta domesticus. The response to sound and air-puff stimulation of the abdominal cerci was monitored with extracellular electrodes placed under the ventral nerve cord. Responses to air puffs were elicited in Grylloblatta while the animal was supercooled to -6°C. The supercooling point was reached and freezing occurred in the range -5.5 to 8.5°C. The upper extinction temperature could not be determined due to massive spontaneous giant fibre activity in the 12–15°C range masking responses to air puffs. Lethal heat coma occurred at 15–20°C, although most animals did not recover from the spontaneous CNS activity which preceded it. The extinction ranges for Acheta giant neurons were 3.5-4.0°C and 42–44°C. Spike number peaked at 33–36 C and amplitude levels diminished as heat or cold coma was approached; -7.5 C was the mean supercooling point. Both species recovered from cold coma if supercooling was avoided; in Acheta , heat coma was also reversible. Giant fibre latencies in Acheta displayed a Q₁₀ of 1.2 above 11–14°C, below which a break occurred in the curve and delays increased sharply. Latencies for the grylloblattid exhibited a Q₁₀ of 2 but no break in the curve was observed until 0° C was approached. Spike number and amplitude increased with temperature until spontaneous CNS activity obliterated responses to air puffs. The potential role of unsaturated fatty acids in low temperature adaptation in Grylloblatta is discussed.     

Sex ratio and adult behaviour of the Antarctic midge Belgica antarctica (Diptera, Chironomklae)

Abstract. 1. The sex ratio in populations of the Antarctic chironomid Belgica antarctica approximates 1:1 at eclosion.
2. Male predominance in surface populations of the short-lived adult persists throughout the summer. The mean ratio, based on data from surface aggregations (austral summer 1977–78) and from sticky traps (1978–79) is about 6:1, with a steady seasonal decline from 10–20:1 to 2–5:1.
3. Males live slightly longer than females but the difference does not account for observed ratios.
4. Samples of adult populations taken from subsurface sites have sex ratios nearer to equality than surface populations.
5. It is concluded that the male-dominated surface populations are equivalent to the male swarms typical of winged Chironomidae.
6. Capture of airborne adults shows that aerial transport as well as water-surface rafting may play a role in dispersal of adults.     

Resource discovery in ant communities: do food type and quantity matter?

1. Omnivorous woodland ant species trade off between the ability to find and behaviourally control food resources. Dominant species can limit the ability of subordinates to harvest certain food items. However, subordinate species, by being faster discoverers, could gain access to such food items by arriving at them first. 2. In this study, we tested the hypothesis that resource‐directed discovery occurs in ant communities and that good discoverers preferentially discover high value resources. We did this by measuring time to discovery and the number of discoveries of high and low levels of two resource types, crickets and honey, for species occurring in Texas and Arizona woodland ant communities. 3. Ants discovered resources roughly 10 times faster in Texas than in Arizona. They discovered crickets more rapidly than honey in both communities, but there was no difference in the discovery of different resource levels. We also found that species were not biased in their discovery of different resource types or levels. 4. These results provide indirect evidence that discovery is directed by resource stimuli but that such directedness does not impact interspecific exploitative competition.