Live or let live: life-history decisions of the breeding female Monteiro's Hornbill Tockus monteiri

Life-history theory maintains that long-lived species such as hornbills (Bucerotiformes) maximize lifetime fecundity by ensuring adult survival, rather than investing in current reproductive output. Unusually, female Tockus hornbills are sealed into the nest cavity during breeding, placing a large burden on the male who feeds her and the nestlings for up to 9 weeks. Early departure to help feed young may improve nestling survival, but could reduce female survival if moult is incomplete. We investigated whether departure time of the female Monteiro's Hornbill Tockus monteiri is more strongly related to measures of female fitness or juvenile condition. Departure was independent of nestling development and growth, instead depending on female state. At departure, variability in condition between females was smaller than at any other stage, implying a strong stabilizing selection on optimal female departure condition. Similarly, moult showed signs of being completed, and variability in the state of moult between females was lowest at departure. Both predictions were met in favour of the hypothesis that Monteiro's Hornbills would base the timing of their departure from the nest on maximizing their own survival. Thus, as predicted, future reproductive potential takes precedence over current reproductive output in a trade-off decision in this species.     

Di‐ and tri‐nucleotide repeat microsatellites for the mealy plum aphid,Hyalopterus pruni

Hyalopterus pruni is an invasive aphid pest in California. To study the population biology of this pest both in California and its native Mediterranean region, we have developed 11 di‐ and tri‐nucleotide repeat microsatellite markers. Each locus amplified in individuals representing the full range of geographical regions and host plants where Hyalopterus is found. Polymorphism was high, ranging from six to 22 alleles per locus in the individuals screened. These loci represent the first microsatellites developed for Hyalopterus and they should be of great value in studying the invasion biology and population structure of this insect pest.     

Mechanisms of the antinociceptive action of (?) Epicatechin obtained from the hydroalcoholic fraction of Combretum leprosum Mart & Eic in rodents

ABSTRACT: BACKGROUND: The mechanisms of the antinociceptive activity of () epicatechin (EPI), a compound isolated from the hydroalcoholic fraction of Combreum leprosum Mart & Eicher. METHODS: were assessed in the model of chemical nociception induced by glutamate (20 mumol/paw). To evaluate the mechanisms involved, the animals , male Swiss mice (25-30 g), received EPI (50 mg/kg p.o.) after pretreatment with naloxone (2 mg/kg s.c. opioid antagonist), glibenclamide (2 mg/kg s.c. antagonist K + channels sensitive to ATP), ketanserin (0.3 mg/kg s.c. antagonist of receptor 5-HT2A), yoimbine (0.15 mg/kg s.c. alpha2 adrenergic receptor antagonist), pindolol (1 mg/kg s.c. 5-HT1a/1b receptor antagonist), atropine (0.1 mg/kg s.c. muscarinic antagonist) and caffeine (3 mg/kg s.c. adenosine receptor antagonist), ondansetron (0.5 mg/kg s.c. for 5-HT3 receptor) and L-arginine (600 mg/kg i.p.). RESULTS: The antinociceptive effect of EPI was reversed by pretreatment with naloxone and glibenclamide, ketanserin, yoimbine, atropine and pindolol, which demonstrates the involvement of opioid receptors and potassium channels sensitive to ATP, the serotoninergic (receptor 5HT1A and 5HT2A), adrenergic (receptor alpha 2) and cholinergic (muscarinic receptor) systems in the activities that were observed. The effects of EPI, however, were not reversed by pretreatment with caffeine, L-arginine or ondansetron, which shows that there is no involvement of 5HT3 receptors or the purinergic and nitrergic systems in the antinociceptive effect of EPI. In the Open Field and Rotarod test, EPI had no significant effect, which shows that there was no central nervous system depressant or muscle relaxant effect on the results. CONCLUSIONS: This study demonstrates that the antinociceptive activity of EPI in the glutamate model involves the participation of the opioid system, serotonin, adrenergic and cholinergic.     

Endogenous chloride channels of insect sf9 cells. Evidence for coordinated activity of small elementary channel units

The endogenous Cl- conductance of Spodoptera frugiperda (Sf9) cells was studied 20-35 h after plating out of either uninfected cells or cells infected by a baculovirus vector carrying the cloned beta-galactosidase gene (beta-Gal cells). With the cation Tris+ in the pipette and Na+ in the bath, the reversal potential of whole-cell currents was governed by the prevailing Cl- equilibrium potential and could be fitted by the Goldman-Hodgkin-Katz equation with similar permeabilities for uninfected and beta-Gal cells. In the frequency range 0.12 < f < 300 Hz, the power density spectrum of whole-cell Cl- currents could be fitted by three Lorentzians. Independent of membrane potential, >50% of the total variance of whole-cell current fluctuations was accounted for by the low frequency Lorentzian (fc = 0.40 +/- 0.03 Hz, n = 6). Single-Cl- channels showed complex gating kinetics with long lasting (seconds) openings interrupted by similar long closures. In the open state, channels exhibited fast burst-like closures. Since the patches normally contained more than a single channel, it was not possible to measure open and closed dwell-time distributions for comparing single-Cl- channel activity with the kinetic features of whole-cell currents. However, the power density spectrum of Cl- currents of cell-attached and excised outside-out patches contained both high and low frequency Lorentzian components, with the corner frequency of the slow component (fc = 0.40 +/- 0.02 Hz, n = 4) similar to that of whole-cell current fluctuations. Chloride channels exhibited multiple conductance states with similar Goldman-Hodgkin-Katz-type rectification. Single-channel permeabilities covered the range from approximately 0.6.10(-14) cm5/s to approximately 6.10(-14) cm3/s, corresponding to a limiting conductance (gamma 150/150) of approximately 3.5 pS and approximately 35 pS, respectively. All states reversed near the same membrane potential, and they exhibited similar halide ion selectivity, P1 > PCl approximately PBr. Accordingly, Cl- current amplitudes larger than current flow through the smallest channel unit resolved seem to result from simultaneous open/shut events of two or more channel units.     

The age, growth and reproduction of the stone loach Noemacheilus barbatulus (L.) in a Dorset chalk stream

SUMMARY.

• 1 In this highly productive chalk stream the stone loach, sampled by electrofishing over a 30 month period, had a high growth rate reaching a mean length of 65 mm in 1 year and 93 mm in 2 years. The fish were short-lived in contrast to most slow-growing populations in the U.K. and Finland with 11 group fish comprising 8.8% and III group fish only 1.1% of the total number.
• 2 The loach were fractional spawners: a 75 mm female produced an estimated 10,620 eggs between late April and early August totalling 46% of the loach's initial weight.
• 3 In March and April some small 0 group females contained only poorly developed eggs and up to 10% of 0 group fish may have failed to spawn.
• 4 Amongst loach >52 mm in length in March and April there was an exponential relationship between absolute fecundity and fish length but no relationship between relative fecundity and length. There was. however, a relationship between fish length and both gonadosomatic index and maximum egg size, which may indicate that large fish began to spawn first.

     

The Effect of Root and Shoot Temperatures on Growth of Ceanothus greggii Seedlings

The effect of varying independently nutrient solution temperature(5, 15, 25 C) and air temperature (10, 20, 30 C) on hydroponicallygrown Ceanothus greggii (Rhamnaceae) seedlings was studied.Increasing both air and solution temperatures caused higherroot and shoot biomass and larger root and leaf areas. Root/shootbiomass ratio increased with increasing solution temperatureand decreased with increasing air temperature. The surface areaof individual leaves decreased with higher air temperaturesbut did not change with solution temperatures. These resultsare opposite to what is predicted from Davidson's balanced rootand shoot activity model. We suggest that nutrient solutiontemperature directly affected root growth and that air temperaturedirectly affected shoot growth. Ceanothus greggii (Trel.) Jeps., root temperatures, soot temperature, plant growth, biomass allocation     

Searching strategies and attack rates of parasitoids of the ash bark beetle (Leperisinus varius) and its relevance to biological control

Abstract.

• 1 Point estimates of parasitoid behaviour indicated that braconid parasitoids of the bark beetle, Leperisinus varius, spend 70% of their host searching time stationary on the bark surface, in sharp contrast to the chalcidoid parasitoids which spend 60–70% of their host searching time moving across the bark surface.
• 2 Aggressive encounters between searching parasitoids are common and the data suggest that they do not occur at random.
• 3 The chalcidoid parasitoids, Cheiropachus quadrum and Eurytoma morio, are more frequently involved in aggressive encounters than expected and can displace ovipositing individuals of other species.
• 4 Attack rates for the parasitoids were estimated to vary from two hosts per day for the braconid Coeloides filiformis to four hosts per day for E.morio, and net reproductive rates vaned from 6.3 for C.filiformis to 0.8 for Coeloides melanotus.
• 5 These data suggest that while all parasitoids of the scolytid can act as primary parasitoids, at least some of the chalcidoid parasitoids are facultative cleptoparasitoids and should be avoided in classical biological control introductions.

     

Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.