Growth regulatory and growth inhibitory effects of Thevetia neriifolia stem extracts on Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract

Helicoverpa armigera, a serious global destructive pest of agricultural crops, is on continuous rise despite several control measures undertaken. The detrimental effects of these measures have created a dire need to explore alternate eco-safe strategies. The present study investigates the growth-regulatory and growth-arrest potential of hexane and methanol extracts of Thevetia neriifolia stems against H. armigera. Investigations revealed that larval feeding and rearing on the extract-containing diet did not result in appreciable larval mortality but delayed the larval growth and development. Both the extracts demonstrated dose-dependent effects exhibiting negative correlation between the weights gained by developmental stages and the extract concentrations. Feeding with extracts also resulted in formation of few larval–pupal and pupal–adult intermediates and significantly reduced percent adult emergence of H. armigera. Current study, however, revealed higher growth inhibitory potential of methanol extracts as compared with hexane extracts. The study attempts to provide an eco-friendly approach for H. armigera management.     

The Snf1‐related protein kinases SnRK2.4 and SnRK2.10 are involved in maintenance of root system architecture during salt stress

The sucrose non‐fermenting‐1‐related protein kinase 2 (SnRK2) family represents a unique family of plant‐specific protein kinases implicated in cellular signalling in response to osmotic stress. In our studies, we observed that two class 1 SnRK2 kinases, SnRK2.4 and SnRK2.10, are rapidly and transiently activated in Arabidopsis roots after exposure to salt. Under saline conditions, snrk2.4 knockout mutants had a reduced primary root length, while snrk2.10 mutants exhibited a reduction in the number of lateral roots. The reduced lateral root density was found to be a combinatory effect of a decrease in the number of lateral root primordia and an increase in the number of arrested lateral root primordia. The phenotypes were in agreement with the observed expression patterns of genomic yellow fluorescent protein (YFP) fusions of SnRK2.10 and ‐2.4, under control of their native promoter sequences. SnRK2.10 was found to be expressed in the vascular tissue at the base of a developing lateral root, whereas SnRK2.4 was expressed throughout the root, with higher expression in the vascular system. Salt stress triggered a rapid re‐localization of SnRK2.4–YFP from the cytosol to punctate structures in root epidermal cells. Differential centrifugation experiments of isolated Arabidopsis root proteins confirmed recruitment of endogenous SnRK2.4/2.10 to membranes upon exposure to salt, supporting their observed binding affinity for the phospholipid phosphatidic acid. Together, our results reveal a role for SnRK2.4 and ‐2.10 in root growth and architecture in saline conditions.     

Temporal patterns of emergence of the riverine dragonfly Onychogomphus uncatus (Odonata: Gomphidae)

The emergence of Onychogomphus uncatus from three stretches at two adjacent canals in Southern France was compared in 1993. Whereas 50% of annual emergence from the two stretches at one canal had occurred after 25 and 36 days, respectively, it had occurred after 5 days at the second, where emergence began 14 days earlier. At the second canal most of the larvae of one generation had overwintered in the final instar but at the first canal only half did so. These differences correlate with greater annual fluctuations of temperature at the second canal which are responsible for high temporal synchronisation. Other factors that may cause differences in seasonal regulation, such as drying up and density, are discussed. Differences exist also in sex ratio and abundance of emerging individuals, particularly between the two collection sites at the first canal.     

Self‐admission in psychiatry: The ethics

Self‐admission to inpatient treatment is a novel approach that aims to increase agency and autonomy for patients with severe psychiatric illness and a history of high utilization of inpatient care. By focusing on brief, preventive hospital admissions in times of increased risk of relapse, self‐admission seeks to reduce the need for prolonged episodes of inpatient treatment. Participants are generally satisfied with the model, which is not surprising given that self‐admission programs allocate a scarce resource—hospital beds—to a select group. However, the patients targeted by these programs are not necessarily those in most need of hospital admission, which may compromise the commonly accepted ‘principle of need’ in allocation of public healthcare resources. In light of the current lack of consistent evidence of the usefulness and cost‐effectiveness of the model, several aspects need to be further studied in order to guide any large‐scale implementation of self‐admission in psychiatry.     

Benefits of familiarity persist after prolonged isolation in guppies

The persistence of familiarity in the Trinidadian guppy Poecilia reticulata , reunited after prolonged periods of separation, was studied and benefits of this association were tested. Choice experiments following 5 weeks of isolation confirmed that the fish continued to prefer familiar group mates. Furthermore, guppies emerged more rapidly from a shelter in the presence of a familiar individual from which they had been isolated, as opposed to a completely unfamiliar individual. This experiment indicated that the benefits associated with the exploration of new surroundings in the presence of familiar fish were not transitory, and could persist over time periods that allow for shoal mixing and re‐assembly, or movement out of the home range.     

White grubs,Holotrichia rustica and Holotrichia mucida (Coleoptera: Scarabaeidae) as pests of teak (Tectona grandis L. f.) seedlings

Abstract Field observations were carried out between 2002 and 2005 on bio‐ecology of white grubs infesting teak (Tectona grandis Linn. f.) seedlings at Ramdongari Forest Nursery, Forest Development Corporation of Maharashtra, Nagpur in central India. The study collected the data required for an integrated pest management strategy against the white grubs. The species damaging teak seedlings were Holotrichia rustica (Burmeister) and H. mucida Gyllenhal. The beetles (adults) of both these species began to emerge just after the pre‐monsoon showers and when the relative humidity had risen rapidly over several days, but before the first monsoon rains. While the adults fed and mated on naturally growing bushes of Ziziphus jujuba, Z. mauritiana, Z. xylopyra, Acacia leucophloea and A. catechu immediately after the emergence from the teak beds in the nursery, the immature stages (grubs) of both species fed on roots of the teak seedling, leading to plant death. This is the first report of (i) damage caused to teak seedlings by grubs of H. rustica and H. mucida, and (ii) of Z. jujuba and Z. mauritiana being hosts for the beetles of H. mucida and H. rustica. It is also the first detailed report on the field bio‐ecology of the H. rustica and H. mucida as major pests of teak. White grubs are among the toughest‐to‐manage pests of economic importance and information presented here on the pest incidence and damage of H. rustica and H. mucida is important to researchers and nursery field managers for the management of these pests on teak.     

Location,reproduction and movement of Neoseiulus californicus (Acari: Phytoseiidae) during the autumn,winter and spring in orchards in the south of France

Field samples and experiments conducted in apple orchards in the south of France showed that Neoseiulus californicus (McGregor) searched for prey on the trees and in the ground cover as late as mid-November 1993, and at least as early in the spring as the end of February 1994. Overwintering females fed, expanded and produced viable eggs within 7.9±0.3 (SE) days given the natural light regime, adequate food and temperatures of 17.0±20.6°C. The first generation of N. californicus developed in the field during March and April 1994. N. californicus nymphs, females and males readily moved over bare ground and through a grass ground cover to trap plants located on stakes 1 m above the ground. In the laboratory, the rate of movement of adult females on 0.5 mm copper wire was a linear function of temperature above a threshold of 11.9±0.9°C. At 25°C they travelled 10 m per h. The migration rate of N. californicus to trap plants on stakes placed in an orchard 13 Apr. increased in 2 weeks from 0.07 to 0.57 predators/trap plant/degree-day, while the migration rate to plants placed directly in the ground cover was 1.45 predators/trap plant/degree-day. The largest population of N. californicus in April occurred on Barley, Hordeum murinum L. This plant produces pollen in April and May, and may be useful in biocontrol programs.     

Growth curves,dental emergence norms,and supplementary morphological observations in known-age captive orangutans

Postnatal development in known-age captive orangutans was studied by collating new data from seven orangutans at Chicago Zoological Park, Brookfield, Illinois, with published and unpublished data from 76 additional captive orangutans. Norms were tabulated for deciduous and permanent dental emergence. Growth curves for weight and linear dimensions in females and males were compared in captive-reared and wild-reared subjects. Hand-reared and mother-nursed captives were compared with respect to dental emergence and weight increase. Differential relative growth of extremity segments was investigated. Pedigree data are presented relative to genetics of hallucal nail absence. Males of various ages were compared with respect to testis size and location and cheek-pad development.     

The influence of potential predators on the habitat preferenda of emerging brown trout

Much research has focused on the developmental behaviour of fish and it has been shown that their sensory and physical capabilities evolve very quickly during their early life. Thus, ontogenesis could influence fishes preferences for particular environmental factors. Little is known about the habitat preferences of trout during the post-emergence phase and it is not known if they correspond to the preference curves established by the PHABSIM method for the' alevin phase'. Here, the downstream movement and habitat preferences of young emerging trout were studied in a flume. In the absence of predators, alevins preferred a water depth of 20 to 30 cm and pebble rather than gravel substratum. When emergence occurred in an area with 1⁺ trout and sculpin, Cottus gobio , almost all the emergent trout remained cryptic. When visible, most of them were in the shallowest area (10cm depth) where their preference for pebble substratum was less marked. The presence of 1⁺ trout and sculpin increased the movement downstream of young trout by 20% without changing the general and diel patterns of catches. Their presence also reduced the initial growth of 0⁺ trout.