Pathogen resistance in the moth Orgyia antiqua: direct influence of host plant dominates over the effects of individual condition

2010 ◽  
Vol 101 (1) ◽  
pp. 107-114 ◽  
Author(s):  
S.-L. Sandre ◽  
T. Tammaru ◽  
H.M.T. Hokkanen

AbstractThe role of pathogens in insect ecology is widely appreciated but remains insufficiently explored. Specifically, there is little understanding about the sources of the variation in the outcome of insect-pathogen interactions. This study addresses the extent to which immune traits of larvae and pupae of the moth Orgyia antiqua L. (Lepidoptera: Lymantriidae) depend on the host plant species and individual condition of the insects. The two host plants, Salix myrsinifolia Salisb. and S. viminalis L., were chosen because they differ in the concentration of phenolic glycosides, harmful to most polyphagous insects. Individual condition was assumed to be reflected in body weight and development time, and was manipulated by rearing larvae either singly or in groups of four. The resistance traits recorded were survival and time to death after fungal infection in the larval stage and the efficiency of encapsulating a nylon implant by the pupae. The survival of the infected larvae was mainly determined by the species of the host plant. Encapsulation response was not associated with the resistance to the pathogen, suggesting that the host plant affected the pathogen rather than the immune system of the insect. Interestingly, the host plant supporting better larval growth led to inferior resistance to the pathogen, indicating a trade-off between different aspects of host plant quality.

2007 ◽  
Vol 79 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Angelo Fontana ◽  
Giuliana d'Ippolito ◽  
Adele Cutignano ◽  
Antonio Miralto ◽  
Adrianna Ianora ◽  
...  

Oxylipins are important signal transduction molecules widely distributed in animals and plants where they regulate a variety of events associated with physiological and pathological processes. The family embraces several different metabolites that share a common origin from the oxygenase-catalyzed oxidation of polyunsaturated fatty acids. The biological role of these compounds has been especially studied in mammalians and higher plants, although a varied and very high concentration of these products has also been reported from marine macroalgae. This article gives a summary of our results concerning the oxylipin chemistry of marine diatoms, a major class of planktonic microalgae that discourage predation from their natural grazers, zooplanktonic copepods, using chemical warfare. These apparently harmless microscopic cells produce a plethora of oxylipins, including short-chain unsaturated aldehydes, hydroxyl-, keto-, and epoxyhydroxy fatty acid derivatives, that induce reproductive failure in copepods through abortions, congenital malformations, and reduced larval growth. The biochemical process involved in the production of these compounds shows a simple regulation based on decompartmentation and mixing of preexisting enzymes and requires hydrolysis of chloroplast-derived glycolipids to feed the downstream activities of C16 and C20 lipoxygenases.


2021 ◽  
pp. 1-14
Author(s):  
Valeria Manera ◽  
Guenda Galperti ◽  
Erika Rovini ◽  
Radia Zeghari ◽  
Gianmaria Mancioppi ◽  
...  

Background: Social apathy, a reduction in initiative in proposing or engaging in social activities or interactions, is common in mild neurocognitive disorders (MND). Current apathy assessment relies on self-reports or clinical scales, but growing attention is devoted to defining more objective, measurable and non-invasive apathy proxies. Objective: In the present study we investigated the interest of recording action kinematics in a social reach-to-grasp task for the assessment of social apathy. Methods: Thirty participants took part in the study: 11 healthy controls (HC; 6 females, mean age = 68.3±10.5 years) and 19 subjects with MND (13 females, mean age = 75.7±6.3 years). Based on the Diagnostic Criteria for Apathy, MND subjects were classified as socially apathetic (A-MND, N = 9) versus non-apathetic (NA-MND, N = 10). SensRing, a ring-shaped wearable sensor, was placed on their index finger, and subjects were asked to reach and grasp a can to place it into a cup (individual condition) and pass it to a partner (social condition). Results: In the reach-to-grasp phase of the action, HC and NA-MND showed different acceleration and velocity profiles in the social versus individual condition. No differences were found for A-MND. Conclusion: Previous studies showed the interest of recording patients’ level of weekly motor activity for apathy assessment. Here we showed that a 10-min reach-to-grasp task may provide information to differentiate socially apathetic and non-apathetic subjects with MND, thus providing a tool easily usable in the clinical practice. Future studies with a bigger sample are needed to better characterize these findings.


2000 ◽  
Vol 90 (4) ◽  
pp. 365-371 ◽  
Author(s):  
P.B. Tanzubil ◽  
G.W.K. Mensah ◽  
A.R. McCaffery

The role of the host plant in the development of larval diapause in the millet stem borer, Coniesta ignefusalis (Hampson) was investigated in northern Ghana in 1996 and 1997. Surveys conducted in farmers' fields in the Guinea and Sudan savannah revealed that of all the upland cereals grown, the insect survived the dry season only in stalks and stubble of pearl millet, Pennisetum glaucum and late sorghum, Sorghum bicolor. This observation was confirmed by results from field trials conducted at the Manga Research Station. In these studies, C. ignefusalis larvae entered diapause only in late millet and late sorghum, with a higher incidence in the former. The insect neither attacked nor entered diapause in maize planted during the same period as the other crops. Results from controlled experiments showed that diapause incidence in the preferred host, millet, was higher in older than in younger plants, suggesting that host plant maturation is a key factor influencing the development of larval diapause in C. ignefusalis.


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