Encapsulation of Eggs and Larvae of Dacnusa dryas (Hymenoptera: Braconidae) by the Alfalfa Blotch Leafminer (Diptera: Agromyzidae) and its Importance in Host-Parasite Coexistence

1990 ◽  
Vol 19 (2) ◽  
pp. 423-427 ◽  
Author(s):  
F. Meloche ◽  
J. C. Guppy
Keyword(s):  
Host Parasite ◽  
Alfalfa Blotch Leafminer ◽  
Eggs And Larvae

Intra- and interspecific genetic diversity of New Zealand hairworms (Nematomorpha)

Parasitology ◽  
2017 ◽  
Vol 144 (8) ◽  
pp. 1026-1040 ◽  
Author(s):  
ZACHARY J. C. TOBIAS ◽  
ARUN K. YADAV ◽  
ANDREAS SCHMIDT-RHAESA ◽  
ROBERT POULIN
Keyword(s):  
Genetic Diversity ◽  
New Zealand ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Population Level ◽  
Morphological Classification ◽  
Widespread Species ◽  
Sampling Locations ◽  
Host Parasite ◽  
Eggs And Larvae

SUMMARYHairworms (Nematomorpha) are a little-known group of parasites, and despite having been represented in the taxonomic literature for over a century, the implementation of molecular genetics in studies of hairworm ecology and evolution lags behind that of other parasitic taxa. In this study, we characterize the genetic diversity of the New Zealand nematomorph fauna and test for genetic structure within the most widespread species found. We provide new mitochondrial and nuclear ribosomal sequence data for three previously described species from New Zealand:Gordius paranensis, Parachordodes diblastusandEuchordodes nigromaculatus. We also present genetic data on a previously reported but undescribedGordiussp., as well as data from specimens of a newGordionussp., a genus new for New Zealand. Phylogenetic analyses of CO1 and nuclear rDNA regions correspond with morphological classification based on scanning electron microscopy, and demonstrate paraphyly of the genusGordionusand the potential for cryptic species withinG. paranensis. Population-level analyses ofE. nigromaculatusshowed no genetic differentiation among sampling locations across the study area, in contrast to previously observed patterns in known and likely definitive hosts. Taken together, this raises the possibility that factors such as definitive host specificity, intermediate host movement, and passive dispersal of eggs and larvae may influence host–parasite population co-structure in hairworms.

SEASONAL DEVELOPMENT, BEHAVIOR, AND HOST SYNCHRONY OF DACNUSA DRYAS (NIXON) (HYMENOPTERA: BRACONIDAE) PARASITIZING THE ALFALFA BLOTCH LEAFMINER, AGROMYZA FRONTELLA (RONDANI) (DIPTERA: AGROMYZIDAE)

1988 ◽  
Vol 120 (2) ◽  
pp. 145-152 ◽  
Author(s):  
J.C. Guppy ◽  
F. Meloche ◽  
D.G. Harcourt
Keyword(s):  
Life Cycles ◽  
Host Larva ◽  
Seasonal Development ◽  
Three Generations ◽  
First Instar ◽  
Host Detection ◽  
Host Pupa ◽  
Host Parasite ◽  
Alfalfa Blotch Leafminer ◽  
Agromyza Frontella

AbstractStudies in eastern Ontario showed that the exotic parasite Dacnusa dryas (Nixon) typically has three generations a year that correspond seasonally to those of its host, the alfalfa blotch leafminer, Agromyza frontella (Rondani). The mature larvae of the third generation enter diapause in September and resume development in the spring. The egg – first instar interval, which occurs within the actively feeding leafminer, developed at rates similar to those of the host larva. The remaining two instars and the pupa, which occur within the host puparium, developed at rates similar to those of the host pupa; in the two non-diapausing generations, the durations of these stages decreased with rise in temperature from 13 to 23 °C. Coincidence of wasp flight and hatch of leafminer eggs was high in all three generations. This host–parasite synchrony results mainly from a sequence of three events during their life cycles: lack of development of the parasite beyond the first instar within the host larva, a temperature-dependent rate of development of the subsequent stages which is similar to that of the host pupa, and different overwintering strategies which result in the parasite emerging later than its host to sustain the relationship. Behavior of the parasite is described in relation to host detection, egg deposition, and reproduction.

The Pathogenesis of Experimental Mycotic Encephalitis

1969 ◽  
Vol 27 ◽  
pp. 356-357
Author(s):  
James A. Swenberg ◽  
Adalbert Koestner ◽  
R.P. Tewari
Keyword(s):  
Electron Microscopy ◽  
Pathogenetic Mechanisms ◽  
Host Parasite

Previous investigations of pathogenetic mechanisms in mycotic encephalitis have been restricted to light microscopic and mycologic approaches. In this study, electron microscopy was utilized to determine the mode of vascular penetration and the cellular and subcellular host-parasite interrelationships in brains of mice infected with Oidiodendron kalrai. This newly isolated fungus was selected because of its ability to consistently produce encephalitis with gross and microscopic lesions similar to those observed in naturally occuring mycoses.

Examination of Schistosome Cercariae and Schistosomules by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 50-51
Author(s):  
D. Johnson ◽  
P. Moriearty
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Light Microscopy ◽  
Surface Structure ◽  
Extensive Study ◽  
Scanning Microscopy ◽  
Host Parasite ◽  
Conventional Electron Microscopy ◽  
Scanning Electron

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.

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