Cardboard nesting cavities may promote the development of Osmia cornuta and reduce infestation of kleptoparasitic mites

Mason bees (Osmia spp.) are receiving increasing attention as they are very effective pollinators of multiple crops. However, different bee-associated kleptoparasites are known which can be detrimental to the development of the bees’ offspring. To date, clear evidence-based guidelines to control these kleptoparasites are lacking for growers. This study investigates whether different types of artificial nesting materials—cardboard tubes and wooden grooved boards—influence the development of the European orchard bee (Osmia cornuta) as well as the infestation rate of kleptoparasitic mites in the bees’ nest. This preliminary study provides insight that cardboard tubes reduce the infestation rate of mites by 81.8% and as such promote successful development of the European orchard bee by 15.5%. Using cardboard tubes over wooden grooved boards should be advised to growers as an effective management strategy to avoid infestation of kleptoparasitic mites and to enhance successful bee development.     

Can altered muscle synergies control unimpaired gait?

Recent studies have postulated that the human motor control system recruits groups of muscles through low-dimensional motor commands, or muscle synergies. This scheme simplifies the neural control problem associated with the high-dimensional structure of the neuromuscular system. Several lines of evidence have suggested that neurological injuries, such as stroke or cerebral palsy, may reduce the dimensions that are available to the motor control system, and these altered dimensions or synergies are thought to contribute to impaired walking patterns. However, no study has investigated whether impaired low-dimensional control spaces necessarily lead to impaired walking patterns. In this study, using a two-dimensional model of walking, we developed a synergy-based control framework that can simulate the dynamics of walking. The simulation analysis showed that a synergy-based control scheme can produce well-coordinated movements of walking matching unimpaired gait. However, when the dimensions available to the controller were reduced, the simplified emergent pattern deviated from unimpaired gait. A system with two synergies, similar to those seen after neurological injury, could not produce an unimpaired walking pattern. These findings provide further evidence that altered muscle synergies can contribute to impaired gait patterns and may need to be directly addressed to improve gait after neurological injury.     

An iterative learning strategy for the auto-tuning of the feedforward and feedback controller in type-1 diabetes

This paper proposes a scheme for the control of the blood glucose in subjects with type-1 diabetes mellitus based on the subcutaneous (s.c.) glucose measurement and s.c. insulin administration. The tuning of the controller is based on an iterative learning strategy that exploits the repetitiveness of the daily feeding habit of a patient. The control consists of a mixed feedback and feedforward contribution whose parameters are tuned through an iterative learning process that is based on the day-by-day automated analysis of the glucose response to the infusion of exogenous insulin. The scheme does not require any a priori information on the patient insulin/glucose response, on the meal times and on the amount of ingested carbohydrates (CHOs). Thanks to the learning mechanism the scheme is able to improve its performance over time. A specific logic is also introduced for the detection and prevention of possible hypoglycaemia events. The effectiveness of the methodology has been validated using long-term simulation studies applied to a set of nine in silico patients considering realistic uncertainties on the meal times and on the quantities of ingested CHOs.     

Incidence of natural enemies of the Colorado potato beetle,Leptinotarsa decemlineata [Coleoptera: Chrysomelidae] on a native host in Mexico

In central Mexico, the center of origin forLeptinotarsa decemlineata (Say) and its principal host plants,L. decemlineata is associated with a diverse complex of natural enemies. Observations during 2 years in Morelos, Mexico revealed 4 species of asopine pentatomids, 7 species of foliar searching carabids, and 2 coccinellids among the predators ofL. decemlineata. Parasitoids include 3 species of tachinids andEdovum puttleri Grissel, an eulophid egg parasitoid. These natural enemies include several predators that have not previously been reported attackingL. decemlineata. University of Maine Agriculture Experiment Station No. 1553     

Correlation between the parameters of contingent negative variation and characteristics of variational pulsometry in Parkinsonian patients

In patients suffering from Parkinson's disease (PD), we analyzed correlations between the parameters of contingent negative variation (CNV) and data of variational pulsometry (according to the measurements of R-R ECG intervals). Studies were carried out on 35 patients (group PD), 49 to 74 years old, with the stage of disease of 1.5 to 3.0 according to the Hoehn-Yahr international classification. In the course of CNV recording (i.e., in the state of a certain functional loading), we observed significant negative correlations between the integral magnitude (area) of this potential and indices of variational pulsometry (RMSSD, SDNN, C. var, and HF) that characterize the intensity of parasympathetic (respiratory) influences on the cardiovascular system. In the control group, such correlations were absent. We found significant correlations between the autonomic balance, CNV magnitude, and stage of PD reflecting the level of generalization of the pathological process. In the subgroup of patients with the PD stage 1.5 to 2.0, significant changes in the mean values of indices of parasympathetic influences during recording of the CNV were not observed, while in another subgroup (the PD stage 2.5 to 3.0), these values increased significantly (P < 0.05 and P < 0.01). If the estimates of the PD stage were low, the CNV area demonstrated greater values (P < 0.01). The disturbance of coordination of muscle-to-muscle interactions in the PD group is, probably, an important factor responsible for parasympathetic dysregulation and suppression of the CNV generation. We found positive correlation between the intensity of parasympathetic influences in the course of CNV recording and the level of postural disorders (r = 0.37, P < 0.05). On the contrary, the CNV magnitude demonstrated a negative correlation with the intensity of these disorders (r = −0.36, P < 0.05), as well as with the level of postural instability (r = −0.55, P < 0.001). We hypothesize that alterations of the autonomic balance and the activity of those cerebral structures, which are responsible for the motor readiness, result, to a significant extent, from weakening of the activity of the noradrenergic system due to degenerative processes developing in cells of the locus coeruleus. The impairment of the latter structure, together with degeneration of neurons of the substantia nigra and a decrease in the level of nigro-striatal dopamine, underlies the pathomorphological pattern of PD. Neirofiziologiya/Neurophysiology, Vol. 40, No. 3, pp. 242–253, May–June, 2008.     

Suitability of some Lantana camara varieties as host plants for the root-feeding flea beetle, Longitarsus bethae

Compatibility between the root-feeding agent Longitarsus bethae Savini & Escalona and the varieties of the target weed Lantana camara L. could influence the chances of successful establishment and effectiveness of this agent as a biocontrol agent of lantana in South Africa. Laboratory experiments were conducted to determine the influence of major South African lantana varieties on feeding, colonization, oviposition preference and larval survival of L. bethae. Feeding preference and the number of adults per plant varied among the varieties. The most damaged and colonized varieties were 150 Orange, 009 Light Pink and 113 Dark Pink. Variety 018 Dark Pink was the least damaged, while 021 Total Pink and 029 White Pink were the least colonized. Females laid the highest number of eggs on variety 150 Orange. The lowest number of eggs was recorded on Australian Richmond Pink and the closely related species Lippia wilmsii. Larval survival differed significantly among the varieties. The highest survival was recorded on 150 Orange. Duration of development also varied significantly among the varieties, with the slowest rate of development recorded on variety 029 Light Pink and the quickest on variety 015 White Yellow. Although variations in female body size were less significant among varieties, males emerging from variety 150 Orange were slightly smaller than those emerged from other varieties. There was a significant tendency for females to select varieties that enhanced the survival of their offspring, which met the predictions of the preference-performance hypothesis. The data suggest that the chances of establishment and successful control of the weed are expected to be much greater on those varieties that were preferred for oviposition and provided better larval performance.     

Di‐ and trinucleotide repeat microsatellites for the parasitoid wasp,Aphidius transcaspicus

The Mediterranean parasitoid Aphidius transcaspicus is currently under investigation as a potential biological control agent for the mealy plum aphid, Hyalopterus pruni, in California. To better understand the biology of this parasitoid, including the potential existence of distinct strains or geographic races, we have developed a set of nine di‐ and trinucleotide repeat microsatellite markers. These markers were examined for variability in individuals from throughout the geographic distribution of A. transcaspicus, and we found between three and 19 alleles per locus. These are the first loci developed for A. transcaspicus and they will be of value in studying the population structure of this potential biocontrol agent and for future diagnostics.     

Isolation and PCR detection of <Emphasis Type="Italic">Enterobacter sakazakii</Emphasis> in South African food products,specifically infant formula milks

Enterobacter sakazakii has recently been identified as an opportunistic pathogen. The current culture-dependent detection methods for these bacteria are time-consuming and in this study a PCR method for the detection of E. sakazakii in South African food products, including an internal amplification control (IAC) was developed. DNA was isolated and amplified from the products and they were plated on selective growth media after pre-enrichment and enrichment in Enterobacteriaceae enrichment broth. Four of the 22 products tested positive for the presence of E. sakazakii, confirmed by PCR detection and growth on selective media. The PCR method proved effective in detecting E. sakazakii in South African products after three days and could serve as an alternative for traditional microbiological techniques.