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Parasitoid Eggs (parasitoid + egg)

Distribution by Scientific Domains

Life Sciences	80%

Selected Abstracts

Biology of Anagrus atomus (Hymenoptera: Mymaridae), an egg parasitoid of the grape leafhopper Arboridia kermanshah (Homoptera: Cicadellidae)

ENTOMOLOGICAL SCIENCE, Issue 3 2004
Shahram HESAMI
Abstract Biology, morphology and oviposition behavior of Anagrus atomus (Linnaeus), an egg parasitoid of the grape leafhopper Arboridia kermanshah Dlabola in Isfahan, Iran, were investigated. Adults were smaller than those so far reported from other regions. Females continuously drummed on plant surfaces with their antennae to search for host eggs. Parasitoid eggs hatched 2,3 days after oviposition, and A. atomus had two larval instars. First instar larvae were sacciform and immobile. Second instar larvae appeared 4 days after oviposition and were very active, and doubled their body length. The prepupal and pupal stages lasted for 1 and 5,6 days, respectively. Adult emergence began 16 days after oviposition, and peaked on day 17. [source]

Gregarious development of the solitary endo-parasitoid, Microplitis rufiventris in its habitual host, Spodoptera littoralis

JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2005
E. M. Hegazi
Abstract:, Earlier research has shown that the koinobiont parasitoid, Microplitis rufiventris, attacks and can develop on early instars of Spodoptera littoralis larvae with preference to third instars. However, the present study was carried out using the newly moulted sixth instar larvae at two different temperatures (20 ± 1 and 27 ± 1°C) to study the developmental interaction between the parasitoid and the last instar host larvae. Parasitoid eggs laid in singly parasitized host larvae invariably died. As the number of parasitoid eggs/host larvae increased, the proportion of eggs that hatched and number of viable parasitoid larvae successfully reached to their final instar increased. The effect of superparasitization seems to be dose (no. of eggs + parasitoid factors)-temperature-dependent. The results demonstrate a kind of ,Allee effect' suggesting that superparasitized last instar S. littoralis larvae provide a better host environment than singly parasitized hosts for the parasitoid, M. rufiventris. This may be due to host's hormone and/or low dose of factors injected with parasitoid eggs. The supernumerary individuals of wasp larvae developed normally to the point of emergence but most did not successfully emerge from the host. The improvement of both hatchability and post-embryonic development of parasitoid wasp was significantly (P < 0.01) greater at 20°C than at 27°C. The results of the present study are useful in understanding the evolution of life-history strategies and host range in parasitic hymenoptera. [source]

Characterization of an I,B-like gene in Cotesia vestalis polydnavirus

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2008
Ya-Feng Chen
Abstract Cotesia vestalis (Braconidae, Hymenoptera) depends mainly on 3 regulatory factors to manipulate its host's development and immune response, including polydnavirus, venom, and teratocytes, among which polydnavirus plays a key role in suppressing the host immune system. In the present work, we cloned the full sequence of gene CvBV-ank2, encoding an I,B-like protein in C. vestalis polydnavirus (CvBV). The full sequence of CvBV-ank2 is 955 bp, encoding 162 amino acids with a calculated molecular mass of 18,355 Da. CvBV-ank2 shares high similarity with the exon I and exon II of CvBV-ank1, which is on the same segment with CvBV-ank2. This result suggests that gene duplication might occur in CvBV-ank1 and CvBV-ank2. Phylogenetic analysis indicated that CvBV-ank2 and CvBV-ank1, both on segment CvBV-S2, are, respectively, closely related with CcBV,26.3 and CcBV,26.2, both on segment Circle26 of C. congregata polydnavirus (CcBV). BLAST search using the sequence of segment CvBV-S2 as a query revealed that segment CvBV-S2 shares 90% max identity with segment Circle26 of CcBV over 67% query coverage. These results demonstrate that there is not only gene similarity, but also segment similarity between CvBV and CcBV. Transcripts of CvBV-ank2 were detected as early as 0.5 h post-parasitization and continued to be detected for 6 days, indicating that CvBV-ank2 might be involved in the early protection of the parasitoid egg. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley-Liss, Inc. [source]

Effects of parasitoid fecundity and host resistance on indirect interactions among hosts sharing a parasitoid

ECOLOGY LETTERS, Issue 6 2003
George E. Heimpel
Abstract We examine the effects of fecundity-limited attack rates and resistance of hosts to parasitism on the dynamics of two-host,one-parasitoid systems. We focus primarily on the situation where one parasitoid species attacks two host species that differ in their suitability for parasitism. While all eggs allocated to suitable hosts develop into adult parasitoids, some of the eggs allocated to marginal host do not develop. Marginal hosts can therefore act as a sink for parasitoid eggs. Three-species coexistence is favoured by low levels of parasitoid fecundity and by low levels of suitability of the marginal host. Our model also produces an indirect (+, ,) interaction in which the suitable host can benefit from the presence of the marginal host, but the marginal host suffers from the presence of the suitable host. The mechanism driving the indirect (+, ,) interaction is egg limitation of parasitoids incurred by allocating eggs to marginal hosts. [source]